ACUS01 KWNS 101950
SWODY1
SPC AC 101948

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0248 PM CDT Mon Jul 10 2023

Valid 102000Z - 111200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST
NEBRASKA INTO WESTERN AND CENTRAL KANSAS...WITHIN A BROADER-SCALE
SLIGHT RISK AREA EXTENDING FROM NORTHWEST TEXAS INTO WISCONSIN...

...SUMMARY...
Scattered strong to severe thunderstorms and a couple of organizing
storm clusters may pose a risk for large to very large hail and
severe wind gusts across parts of the Upper Midwest into Great
Plains this afternoon into tonight.

Main change at 20Z was to expand severe probabilities westward
across Colorado as storms have formed near the Front Range. A very
moist air mass remains over the eastern CO counties with mid to
upper 60s dewpoints. For more information see mesoscale discussion
1483.

..Jewell.. 07/10/2023

.PREV DISCUSSION... /ISSUED 1129 AM CDT Mon Jul 10 2023/

...Upper Midwest into Central Plains...
Morning satellite imagery show several low-amplitude shortwave
troughs moving through the northern periphery of the upper ridging
extending from the southern High Plains into the northern Rockies.
One of these shortwaves is moving into central SD, with continued
southeastward motion towards the Mid MO Valley anticipated. In
addition to this approaching shortwave trough, a cold front
stretches from western SD eastward through southern MN and northern
WI and then back northeastward across Upper MI. This boundary is
expected to push gradually southward throughout the day, moving
across much of SD, southern MN, and northern/central WI.

Convergence along this boundary is expected to result in
thunderstorm development during the late afternoon across southern
MN and northern/central WI. Low 60s dewpoints are already in place
in this area, with additional moisture advection helping to offset
mixing throughout the day. As such, low 60s will likely still be in
place later this afternoon, helping to support moderate buoyancy
amid late afternoon temperatures in the upper 80s/low 90s. This
region will also be on the southern edge of the stronger
northwesterly flow aloft around the cyclone centered over northern
Ontario. These environmental conditions should support robust
updrafts along the front. Hail is possible with the initial
development, but low-level lapse rates will likely support
outflow-dominant storm structures, with upscale growth into one or
more linear segment anticipated quickly. These convective lines are
then expected to shift southward into more of central WI northern IA
during the evening before dissipating amid nocturnal stabilization.

Farther west (from the Mid MO Valley into NE), thunderstorms are
expected to develop ahead of the primary frontal zone along a
sharpening pre-frontal trough, with low-level convergence along the
trough augmented by ascent attendant the approaching shortwave.
Afternoon dewpoints along this trough will likely be in the mid 60s,
supporting strong buoyancy amid steep mid-level lapse rates and
surface temperatures in the low 90s. Robust shear will be in place
as well, as strong southerly surface winds veer to northwesterly
aloft. This environment should support supercells capable of large
to very large hail and strong outflow. Some upscale growth is
possible, with the resulting convective line moving south into
southern NE.

Another shortwave trough is moving into western CO, which is
expected to aid in the development of thunderstorms along the lee
trough in eastern CO, where the environment will be similar to that
over NE. Initial supercells capable of large to very large hail and
strong downdrafts are anticipated, before potential upscale growth
in this area as well. Interaction between these more
eastward-progressing storms and then more southward-progressing
storms in NE is likely. The latest guidance suggests this
interaction will lead to the development of a robust MCS capable of
significant wind gusts.

...Southern High Plains...
Afternoon thunderstorm development is anticipated across the higher
terrain before then moving into the moderately unstable airmass
downstream across eastern NM and west TX. The airmass across west TX
will be characterized by greater low-level moisture/instability,
supporting more robust updrafts and an increasing risk of a few
severe storms. Large hail and damaging winds will be possible.
These storms may persist for a few hours and spread into southwest
OK before weakening.

...Central MT...
A few strong to severe storms are possible across the region where
modest destabilization and shear will be in place ahead of a lead
short wave trough progressing into the northern Rockies. Initial
development is anticipated across the higher terrain before then
spreading into more of south-central Montana later this afternoon
into tonight.

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 122002
SWODY1
SPC AC 122000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Wed Jul 12 2023

Valid 122000Z - 131200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTHERN ILLINOIS/FAR NORTHWESTERN INDIANA...AND PARTS OF EASTERN
KANSAS INTO MISSOURI...

...SUMMARY...
Severe thunderstorms remain possible across much of Missouri,
Illinois, and adjacent portions of the central Plains and Midwest
this afternoon through tonight. A few tornadoes should occur this
afternoon and evening across parts of northern Illinois into far
northwestern Indiana, with a strong tornado possible. Otherwise,
damaging winds and large hail should occur with intense
thunderstorms that develop, with some potential for significant (75+
mph) severe winds and very large hail across parts of Missouri and
Kansas.

...20Z Update...
Primary change with this update was to introduce higher tornado
probabilities in a narrow corridor across northern IL and far
northwestern IN, including Chicago. Recent VWPs from KLOT show
impressive low-level shear (0-1 km 35-40+ kt) and enlarged/curved
low-level hodographs associated with a focused low-level jet. In the
wake of a remnant MCS and lessening precipitation shield, it appears increasingly likely based on recent visible satellite imagery and
surface observations that sufficient destabilization to support
surface-based convection will occur across this region over the next
few hours. Given the very favorable low-level and deep-layer shear
available, concern has increased that any supercell which forms in
this environment will be capable of producing a tornado. Some
potential will exist for a strong tornado as effective SRH
strengthens to around 250-350 m2/s2 along/near the developing warm
front. The Slight Risk has also been expanded northward in southern
Lower MI to account for a small bowing cluster which may develop.

No changes have been made to the Enhanced Risk across parts of
eastern KS into MO. 18Z sounding from TOP showed warm low/mid-level temperatures and a cap which should continue to inhibit robust
convection for at least a couple more hours. Still, intense
thunderstorm development is expected later this evening in tandem
with a modestly strengthening low-level jet.

..Gleason.. 07/12/2023

.PREV DISCUSSION... /ISSUED 1140 AM CDT Wed Jul 12 2023/

...Northern IL/southern WI east to northwest OH/southern lower MI...

Current MCS continues a general weakening trend based on IR cloud
tops, radar trends and recent reports. Air mass recovery in the wake
of the morning convection currently appears plausible, aided by a
modestly enhanced low-level jet later this afternoon and evening.
Steepening mid-level lapse rates will contribute to moderate/pockets
of strong MLCAPE this afternoon, and coupled with 40-50 kts of
deep-layer shear would result in a favorable parameter space for
supercell development by late afternoon/early evening with all
severe hazards possible. Will introduce a small 5 percent tornado
probability area across this region, where forecast sounding
hodograph structure appears most favorable for low-level
rotation/tornado potential east of a weak surface low.

...KS/MO/OK this evening...
Redevelopment of severe storms appears probable late this
afternoon/early evening in the vicinity of an outflow boundary that
continues to slow its southward motion across northern portions of
KS/MO. Strong/locally extreme MLCAPE is anticipated near/south of
this boundary with substantial shear in the cloud-bearing layer.
Storms that develop will likely initially possess supercell
characteristics with severe hail (possibly significant) and wind,
with eventual upscale growth into one or two MCSs capable of
potentially significant severe gusts. The Enhanced Risk area has
been reoriented based on expected outflow boundary location later
this afternoon and a consensus of 12z CAM guidance/HREF ensemble max probabilities.

...IN/OH into New England...
A surface quasistationary front currently extends from northern IN
into NY and New England. Substantial heating is underway east of
the front, which should allow for destabilization and scattered
afternoon thunderstorm development. This area lies along the
southern fringe of stronger west/southwesterly flow aloft, with
25-35 knots of deep-layer shear. This may be sufficient for a few
strong storms later today capable of gusty/damaging winds.

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 131955
SWODY1
SPC AC 131953

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Thu Jul 13 2023

Valid 132000Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
NORTHERN NEW YORK AND WESTERN VERMONT...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE PLAINS...PARTS OF THE OHIO VALLEY...AND NORTHEAST...

...SUMMARY...
Numerous severe thunderstorms are likely today across eastern New
York and western Vermont, with scattered severe thunderstorms
possible across parts of the Ohio Valley and portions of the
southern/central Plains. Damaging winds, large hail, and perhaps a
couple of tornadoes are possible in these areas. Isolated very
large hail may occur across parts of the central Plains.

...Northeast...
A line of storms continues to push rapidly east across NY, with
strong wind gusts measured recently. Instability remains favorable
ahead of the line, and heating continues as well. While the primary
threat is for damaging winds, effective SRH over 150 m2/s2 and
deep-layer shear over 30 kt will also favor a few supercells with
hail or brief/weak tornado risk. For more information see mesoscale
discussion 1523.

Farther south, a relative minimum in thunderstorm coverage is
expected over southern PA into MD, and the Slight Risk has been
modified in these areas as the severe risk should remain isolated.
The primary risk farther south is expected to remain over the OH
Valley, WV and western VA.

...Plains...
Extreme moisture and instability is noted into eastern CO where
dewpoints are in the 68-72 F range. The backed/easterly low-level
flow beneath moderate high level flow is resulting in long
hodographs with around 50 kt effective shear. The result should be
very large hail, as well as developing damaging wind threat as
storms increase in coverage and blend outflows through the OK/TX
Panhandles and into western OK. For more information see mesoscale
discussion 1519.

..Jewell.. 07/13/2023

.PREV DISCUSSION... /ISSUED 1119 AM CDT Thu Jul 13 2023/

...NY into New England...
Water vapor loop shows a strong mid-level shortwave trough
moving across southern Ontario, with a surface cold extending
extending from Lake Erie into central/eastern OH. A warm front
extends east from a surface low over southeast Ontario Province to
the coast near Portland, ME. The cold front will move steadily east
this afternoon into NY where thunderstorm development is underway,
with an increase in coverage likely over the next few hours.
Surface dewpoints in the mid 60s and substantial heating will yield
pockets of MLCAPE over 2000 J/kg, along with moderately steep low
and mid-level lapse rates. Shear profiles are also rather strong,
conducive for organized/supercell structures. Thunderstorms are
expected to intensify over eastern NY in the Hudson Valley vicinity
before spreading into western New England. A mixture of discrete
supercell storms and bowing structures is expected, capable of large
hail and damaging wind gusts, and perhaps a tornado or two. Storms
should weaken during the evening while moving into a more stable
environment with time.

See recently issued Mesoscale Discussion 1517 for additional details
on short-term thinking in this area.

...KY/WV/OH...
As the cold front sags southward into the upper OH Valley by
mid-afternoon, scattered thunderstorms are expected to develop.
Sufficient westerly flow aloft and MLCAPE of 1500 to locally 2000
J/kg will promote supercells and organized clusters capable of
damaging winds and severe hail.

...High Plains from SD to TX...
A broad upper-level ridge is present today over the southwest
states, with the southern fringe of stronger westerlies extending
across CO/KS. A surface dryline will become established by late
afternoon extending from the Black Hills vicinity across eastern CO.
Forcing will be subtle, however minimal CINH and ample
moisture/instability will result in widely scattered intense storms
along the dryline, spreading southeastward through the evening.
Supercells capable of very large hail appear possible. Storms over
western SD/NE, and also over southwest KS and adjacent TX/OK
panhandles may persist well into the night and spread eastward
across those states.

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 141632
SWODY1
SPC AC 141630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Fri Jul 14 2023

Valid 141630Z - 151200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER CENTRAL
AND EASTERN KANSAS...WESTERN MISSOURI...AND NORTHERN OKLAHOMA...

...SUMMARY...
Severe thunderstorms producing damaging winds, with gusts over 75
mph likely, and large hail are forecast today over portions of the
central and southern Plains. Isolated damaging gusts or marginal
hail will also be possible over parts of the Mid Atlantic and
southern New England, the Great Lakes, and the Mid-Mississippi
Valley.

...Central and southern Plains...
An ongoing cluster of severe storms was located over
southwest/south-central NE at 16z, with a history of large hail and,
more recently, severe gusts. This small complex is within a zone of
warm advection in the 850 to 700-mb layer, and will likely continue
moving southeastward along an instability gradient this afternoon
and evening. Aided by steep lapse rates in the midlevels and
strong-locally extreme MLCAPE across central KS/central and eastern
OK this afternoon, an expected evolution into a fast-moving MCS with significant severe wind gust potential is anticipated. The Enhanced
Risk was expanded west over KS based on morning CAM guidance, and
also adjusted slightly southward over OK. The Slight and Marginal
Risk areas were also expanded south as well-organized and
fast-moving MCSs often persist longer than reflected in some
operational guidance. Given the CAPE-shear parameter space,
supercell potential will also exist with this MCS and an attendant
risk for large hail.

Farther west, isolated supercell development appears possible across
southeast WY/northeast CO late today, along the southern fringe of
stronger WNW mid-level flow. Large hail will be possible.

...MO/IA/IL/WI...
A cold front will move into parts of southern IA, northern MO,
northwest IL, and southern WI by afternoon, and scattered
thunderstorm development is expected in the vicinity of the front.
Moderately strong westerly mid-level winds and ample CAPE will
promote a few organized clusters capable of hail and damaging wind
gusts for a few hours through this evening.

...East Coast from NC to New England...
Diurnal heating of a moist air mass (dew points averaging upper
60s-mid 70s) will lead to moderate CAPE across a rather large area
this afternoon. A weak shortwave trough will approach the
mid-Atlantic states this afternoon, contributing to the development
of widely scattered thunderstorms from NC across the Mid-Atlantic
into southern New England. Winds aloft will be relatively weak
(25-30 knots), but the potential will exist for a few slow-moving
multicell clusters capable of gusty/damaging winds this afternoon
and early evening.

..Bunting/Weinman.. 07/14/2023

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 182002
SWODY1
SPC AC 182000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Tue Jul 18 2023

Valid 182000Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE TENNESSEE VALLEY...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Scattered to numerous damaging winds are expected to continue this
afternoon and early evening into the Tennessee and lower Ohio
Valleys. Other strong to severe storms should occur across parts of
the Northeast and northern/central Plains.

...20Z Update...
Severe probabilities have been adjusted from the eastern portions of
the central Plains into the mid MS Valley and lower OH Valley in the
wake of the ongoing MCS across KY/TN. Scattered to numerous
severe/damaging winds remain likely with this MCS as it continues
eastward across the TN and lower OH Valleys this afternoon and early
evening. See Mesoscale Discussion 1618 for more details on the
near-term severe threat across this area.

Some potential for redevelopment later this evening and overnight
remains across parts of MO and vicinity in a strengthening low-level
warm advection regime. Large hail may occur with any supercell that
can form in this environment, and severe/damaging winds appears
possible with any convection that can grow upscale into a cluster.
Have therefore maintained the Slight Risk across portions of this
area.

A Slight Risk has also been introduced over the Black Hills of
western SD into parts of northern NE. While overall thunderstorm
coverage may remain fairly isolated across this region, any
convection that can be sustained will likely be supecellular given
2000-2500+ J/kg of MLCAPE and 40-50 kt of deep-layer shear. Isolated
very large (2+ inch) hail and severe wind gusts should be the main
threats.

..Gleason.. 07/18/2023

.PREV DISCUSSION... /ISSUED 1134 AM CDT Tue Jul 18 2023/

...Middle/Lower Missouri Valley to Tennessee Valley...
Ongoing bowing complex of strong/severe storms continues moving
southeast at 40-45 kt across southeast MO. Downstream heating of a
very moist environment (dew points 75-80 Deg F) and seasonably
strong mid-level northwesterly flow averaging 40-45 kts is expected
to result in a continued southeast movement into an increasingly
favorable environment for a forward-propagating MCS/potential for
significant severe gusts. Please refer to recently-issued MCD 1613
for the latest short-term thinking in this area.

Additionally, another round of elevated thunderstorms is expected
to develop later today along the convectively influenced northwest/southeast-oriented boundary across Missouri. This may
include elevated supercells with a threat for large (isolated very
large) hail given strong elevated instability and substantial deep
layer shear. With time, upscale growth will be possible and a severe
wind threat could materialize.

...Northern Plains...
Low-level moisture advection and surface heating will lead to
moderate-strong instability across central North Dakota and South
Dakota by this afternoon. This instability, combined with
convergence from an approaching/sharpening cold front and ascent
with a mid-level shortwave trough, should be sufficient for
strong/severe thunderstorm development near the front this
afternoon. Mid-level winds of 45-55 kt will contribute to
favorable wind profiles for supercells and related risk for large
hail, some potentially 2+ inches in diameter.

...Northeast/Mid-Atlantic States and New England...
Modest height falls will continue to overspread the region,
influenced by moderately strong cyclonic mid-level flow with an
upper-level trough over northern Ontario/Quebec. Relatively long
hodographs during peak heating/maximized instability will support
some potential for sustained/organized storms capable of wet
microbursts and isolated wind damage. Some hail will also be
possible. Refer to MCD 1614 for short-term thinking in this area.

...Central High Plains...
A few thunderstorms are possible late this afternoon as low-level
upslope flow evolves, with increasing low-level moisture to the
north of a surface low. The favorable environment may be
relatively short-lived given the late-day increase in moisture, but
a favorable environment will exist for a few severe thunderstorms in
an environment with 2000+ J/kg MLCAPE and supercell wind profiles.

...Great Basin...
A deeply mixed boundary layer is expected today across the Great
Basin with ample instability for scattered thunderstorms across much
of the region. A belt of stronger mid-level winds of 25-30 kt will
exist from east-central Nevada into north-central Utah. This may
support some storm organization with the potential for isolated
strong/severe wind gusts given the well-mixed sub-cloud layer/steep
low-level lapse rates.

...Southern Arizona...
Thunderstorms should develop over the Rim/White Mountains
and higher terrain of southeast Arizona this afternoon. The region
will be nearly coincident with the upper high. While mid-level
steering flow will be weak, a westerly component of near-surface
winds will likely support propagation into the desert floor,
particularly across southeast Arizona within a relatively moist but
hot/deeply mixed boundary layer. Some strong, potentially
severe outflow winds may occur late this afternoon/early
evening.

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 271957
SWODY1
SPC AC 271955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Thu Jul 27 2023

Valid 272000Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
EASTERN MINNESOTA...WISCONSIN NORTHWOODS...WESTERN UPPER MICHIGAN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN THE
SOUTHERN NEW ENGLAND INTO THE MID-ATLANTIC...

...SUMMARY...
Severe gusts and hail (some potentially significant) are possible
the remainder of this afternoon and evening in parts of Minnesota
and Wisconsin. Damaging to severe gusts also may occur today with thunderstorms in parts of the Mid-Atlantic/New England regions, and
the central High Plains and Rockies.

...20Z Update...
A few minor changes to wind probabilities from the Ohio Valley into
the Northeast as well as modifications to the general thunder area
based on the latest observational trends. The prior forecast
reasoning otherwise remains valid.

..Wendt.. 07/27/2023

.PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jul 27 2023/

...Northeast...
A well-defined shortwave trough is moving across central NY today.
Forcing for ascent ahead of this trough will aid in the development
of scattered thunderstorms by mid-afternoon from parts of PA and
southeast NY into southern and eastern New England. Rich low-level
moisture and pockets of strong daytime heating will yield MLCAPE
values around 2000 J/kg. Rather strong wind fields will promote
relatively fast-moving storms capable of wind damage. Parts of
southern New England may also have sufficient low-level vertical
shear to pose a risk of a tornado or two. Please refer to MCDs
#1736 and #1737 for further details.

...Western Great Lakes/Upper Midwest...
Fast zonal flow is present today across the northern Plains, with
50-70 knot westerly winds above 6km noted on forecast soundings. A
surface boundary is sagging southward across MN, and should provide
the focus for rapid thunderstorm development later this afternoon.
A very unstable air mass will develop from central MN into northern
WI, along with sufficient deep-layer shear for supercells capable of
very large hail. Storms are expected to persist well into the
evening as they spread eastward into parts of Upper MI and much of northern/central WI. The risk of rather widespread damaging winds
will increase across this area. Given the favorable environment and
consistent 12z model signals, have upgraded portions of this area to
ENH.

...Rockies and High Plains...
Similar to yesterday, scattered high-based showers and thunderstorms
are expected to develop over the high terrain of CO northward into
much of WY and MT. Fast westerly flow and steep low-level lapse
rates will promote a risk of damaging wind gusts in some of these
storms. As activity spreads eastward into the Plains, a few more
robust updrafts may also produce large hail.

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 281257
SWODY1
SPC AC 281255

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 AM CDT Fri Jul 28 2023

Valid 281300Z - 291200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
SOUTHEASTERN SOUTH DAKOTA TO THE SOUTHERN LAKE MICHIGAN VICINITY...

...SUMMARY...
Severe storms are most probable from southeast South Dakota across
Iowa, northern Illinois and southern Wisconsin this afternoon and
evening, with corridors of damaging wind and large hail. Other
scattered strong to severe storms are expected from Ohio into
Virginia, and across the northern High Plains.

...Synopsis...
In mid/upper levels, a persistent, strong anticyclone will remain
centered over the southern Rockies, with ridging eastward across the
Mid-South and southwestward over northern Baja. The northern-stream
belt will start the period mostly zonal, but start to buckle some
through the period as a series of mostly low-amplitude shortwaves
traverses a re-amplifying eastern CONUS mean trough. Ridging also
will amplify from the 500-mb high north-northwestward over the
northern Rockies. These processes will yield a belt of difluent,
northwesterly to west-northwesterly flow over the northern Plains,
Upper Midwest, Upper Great Lakes, and lower Ohio Valley.

At the surface, 11Z analysis showed a cold front across northeastern
ON to Lower MI, where it was broken up by an area of convective
outflow. A warm front became apparent farther southwest over parts
of northern IA, and southern MN, to a low in the SUX area, with the
cold front extending westward over northern NE to northern WY. The
low should migrate eastward across the WI/IL border region to near
TOL by the end of the period, along the aggregate baroclinic zone
from synoptic and convective influences.

...North-central Plains to central Appalachians...
Scattered to locally numerous thunderstorms are possible through the
period in this corridor. The main concern remains upscale growth of
one or more organized thunderstorm clusters into MCSs with organized rear-inflow jet(s), cold pool(s) and attendant severe wind. Early-
stage, relatively discrete thunderstorms also should produce large
hail -- perhaps significant/2+ inch diameter in western parts of the
outlook area, where deep-layer lapse rates and low-level hodographs
will best favor hail-producing supercells.

In the area from central/southeastern SD to northern IL, strong
diurnal heating will steepen low-level lapse rates amid 60s and low
60s F surface dewpoints, combining with steep midlevel lapse rates
to yield MLCAPE in the 3000-4500 J/kg range. This will support
rapid development and upscale growth of convection once the cap is
broken, likely preferentially near the baroclinic zone and surface
low where low-level convergence should be maximized. Deep shear
will be favorable for early-evolution supercells as well as bowing
structures during upscale aggregation, with effective-shear
magnitudes in the 45-55-kt range.

Current unconditional probabilities don't depict a substantially
denser, greater-magnitude wind threat that *could* develop somewhere
within the broad swath of the "slight" and "enhanced" lines. The
"enhanced" area simply represents what still appears to be the best
apparent environment for such an event, but still may shift around
in position and shape today, as mesoscale/convective trends and
shorter-fused progs warrant. This uncertainty is partly because of
mesoscale questions regarding the influence (and possible downshear intensification of) ongoing activity and its boundaries, as well as
substantial differences among both CAM and synoptic-scale guidance
on convective coverage/organization later today, in that more-ideal
environment from the Plains to the Corn Belt.

...Northern High Plains...
Widely scattered to scattered thunderstorms should form this
afternoon over the higher terrain of southwestern MT and northern
WY, moving eastward the east-southeastward. Isolated severe gusts
and marginal hail will be possible. This projected path conforms
both to:
1. The gradual anticyclonic curvature of ambient/mean flow near the
mid/upper ridge, and also
2. The orientation of a supportive, boundary-layer moist plume
whose axis should remain across southern MT into western SD.

Near that moist axis, which should feature 50s F surface dewpoints,
diurnally steepened low/middle-level lapse rates will contribute to
500-1000 J/kg MLCAPE, a well-mixed boundary layer, and minimal
MLCINH ahead of the orographic initiation regime by mid/late
afternoon. Surface flow should veer with time from northerly to
easterly and southeasterly, maximizing storm-relative winds in the
inflow layer, though absolute speeds may be weak. Still, strong
veering with height will contribute to 45-55-kt effective-shear
magnitudes. Some of this activity may persist well into tonight
and portions of the Dakotas with a sporadic wind threat, as it
encounters increasing moisture and continued favorable storm-
relative winds above a nocturnally stabilizing near-surface profile.


...Northern ME...
Widely scattered to scattered thunderstorms are expected to develop
along/ahead of a cold front over southern QC, upshear from this
region, during the afternoon. Some of this activity may cross
northern ME before weakening, with the potential for isolated,
marginally severe gusts and/or hail. Forecast soundings suggest a
combination of diurnal heating and sufficient moisture (e.g.,
mid-60s F surface dewpoints) will offset modest mid/upper-level
lapse rates and yield around 1000 J/kg MLCAPE. Nearly
unidirectional deep-layer wind profiles will limit low-level shear,
but with strong flow in mid/upper levels, effective-shear magnitudes
around 35-45 kt reasonably appear in modeled wind profiles, prior to
convective influences. As such, organized multicells and isolated
supercells may occur.

...AZ...
Isolated severe gusts are possible again this afternoon from
thunderstorms propagating westward to northwestward over portions of
southern AZ -- mainly developing over orographically favored areas
early, then perhaps on a couple of subsequent outflow boundaries.
IR satellite imagery indicates extensive cloud cover from earlier
convection over MX is breaking up, and substantial diurnal heating
once again is expected across the region. MLCAPE up to about 500
J/kg should develop as enough moisture is maintained in a deep, hot,
well-mixed boundary layer that supports locally intense downdrafts.

..Edwards/Broyles.. 07/28/2023

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 281953
SWODY1
SPC AC 281951

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Fri Jul 28 2023

Valid 282000Z - 291200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON INTO EARLY TONIGHT FROM NORTHERN IA TO NORTHERN IN AND
VICINITY...

...SUMMARY...
Severe storms are most probable from Iowa and southern Minnesota
eastward to northern Illinois/southern Wisconsin late this
afternoon/evening, and continuing into southwest Lower Michigan and
northern Indiana tonight. Damaging winds and large hail are the
main threats.

...20Z Update...
Minor changes were made to the wind probabilities in the upper
Midwest and upper Ohio Valley vicinity. The remainder of the outlook
is unchanged as the previous forecast reasoning remains valid.

..Wendt.. 07/28/2023

.PREV DISCUSSION... /ISSUED 1120 AM CDT Fri Jul 28 2023/

...SD/NE to the Upper Midwest through tonight...
Within a largely zonal flow regime, embedded speed maxima will move
eastward over the central/northern Plains and the upper MS Valley -
the most pronounced of which is now over ND. Convection and an
outflow/frontal surge with this ND speed max will eventually
interact with the north edge of the more moist/unstable air mass
from southeast SD/southern MN into northern IA/southern WI later
this afternoon/evening. The timing of convective initiation and
details of subsequent storm evolution are both somewhat in question,
but effective bulk shear near 50 kt and MLCAPE of 2500-4000 J/kg
will conditionally favor splitting supercells initially with very
large hail. Convection could then grow upscale into an MCS this
evening into tonight, with an attendant threat for damaging winds.

...Upper OH Valley into the Mid-Atlantic this afternoon/evening...
A remnant MCV over northern IN will move eastward over OH today, and
additional convection expected today along the associated outflow boundary/differential heating zone across central/eastern OH. The
stronger flow with the MCV will tend to trail the lead outflow, so
multicell storms with occasional downburst winds will be the primary
threat this afternoon. Farther east, vertical shear will be weak,
but surface heating over the higher terrain and weak convergence
along a diffuse baroclinic zone will support scattered thunderstorm
development this afternoon from the central Appalachians into parts
of the Mid-Atlantic. Isolated strong downburst winds for a few
hours this afternoon/evening will be the main concern this area.

...Northern ME this evening...
A northern stream shortwave trough and associated surface cold front
will cross Quebec and northern ME later this afternoon into this
evening. Midlevel lapse rates will not be steep, but MLCAPE near
1000 J/kg and relatively long hodographs will support the potential
for wind damage with a band of storms along and just ahead of the
cold front.

...Southern MT to northeast CO and vicinity through tonight...
Subtle speed maxima will move around the northern periphery of the
southern Rockies midlevel high, interacting with terrain
circulations and a deepening mixed layer later this afternoon.
High-based storm development is expected around mid afternoon from
southern MT to southeast WY/northeast CO, where storm clusters will
move off the high terrain in response to mid-upper westerlies, and
inverted-V profiles will favor isolated strong-severe outflow gusts
as the main concerns.

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 291300
SWODY1
SPC AC 291259

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 AM CDT Sat Jul 29 2023

Valid 291300Z - 301200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
SOUTHEASTERN NEBRASKA TO NORTHWESTERN MISSOURI...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK...EXTENDING SOUTHEASTWARD TOWARD THE EASTERN
OZARKS/SOUTHERN IL REGION...AS WELL AS FROM PORTIONS OF THE CENTRAL APPALACHIANS AND MID-ATLANTIC TO NEW ENGLAND...AND IN TWO SEPARATE
AREAS OVER PORTIONS OF THE CENTRAL AND NORTHERN GREAT PLAINS...

...SUMMARY...
Widely scattered to scattered strong to severe thunderstorms are
possible over southern New England into the Mid Atlantic states on
Saturday. A few strong/severe storms may also be noted across the
central High Plains. Damaging gusts are the primary hazard, though
hail is possible across the Plains.

...Synopsis...
In mid/upper levels, a persistent, strong anticyclone will persist
over the southern Rockies, with prominent ridging across the
southern Plains to the lower Mississippi Valley region. Another
ridge -- extending northwestward through the Central/northern
Rockies -- will amplify through most of the period. Downstream, a
belt of northwest to west-northwest flow aloft will persist from
much of MT to the Upper Great Lakes and much of the Ohio Valley,
where the flow aloft becomes more difluent.

The mean trough and associated cyclonic flow will continue to cover
much of the eastern CONUS, with the strongest flow over the Lower
Great Lakes to New England, and northern Appalachians. An embedded, convectively reinforced shortwave trough -- apparent in
moisture-channel imagery from southwestern ON to northern KY -- will
pivot eastward across the northern Mid-Atlantic region to western
New England through 00Z, with some weakening possible.

At the surface, 11Z analysis showed a low near the northern shore of
Lake Erie in southern ON, with cold front southwestward to another
low over north-central MO, then westward over northern KS. An
extensive outflow boundary south of the front -- from western PA
across western WV and much of KY -- will decelerate with the cold
front catching up, and the combined baroclinic zone becoming more
prominent through the day. The eastern low should move/redevelop
eastward along the frontal zone, crossing the inland northern
Mid-Atlantic today and southern New England this evening, followed
by the cold front.

...Central Plains to lower Missouri Valley/lower Ohio Valley...
A well-organized MCS is crossing parts of central/southern NE with well-developed cold pool apparent in surface obs, rear-inflow jet in radar-velocity imagery, and history of several measured-severe
gusts. Refer to the remainder of SPC Severe Thunderstorm Watches
565, 566 and related mesoscale discussions for near-term coverage of
the threat. Guidance has been inconsistent -- including most CAMs,
which have not been particularly reliable on this MCS outside
perhaps the 00Z NSSL WRF, which depicted this, but was too slow.
This includes some forecasts of a potential temporary weakening over
northern MO, which is possible, but for which uncertainty is too
great to attempt an unconditional break in spatial probabilistic
continuity.

In either event, the associated pressure/UVV perturbation may lead
to a continuation or invigoration of severe potential over eastern
MO into parts of the lower Ohio Valley, perhaps as far as the
Tennessee Valley, near both the outflow-reinforced baroclinic zone
and low-level moist axis. Rich low-level moisture, with surface
dewpoints in the upper 60s to low 70s F, will continue to be
available in the projected track, as well as a diurnally
heated/destabilizing airmass from midday into afternoon.
Accordingly, severe-wind probabilities have been introduced, and
isolated significant-severe gusts cannot be ruled out.

...Central/Northern High Plains...
Previous outlook reasoning still appears valid at this time for the
central High Plains part of the outlook, which should be well west
of the stabilizing influence of the MCS now crossing parts of the
lower central Plains. However, farther north across the northern
High Plains, concern has increased for the threat of supercells to
develop this afternoon across the eastern MT/western Dakotas
corridor, near and just east of a surface boundary and near a
low-level moist axis. This activity should move southward to
southeastward, offering severe hail (some potentially above two
inches in diameter where inflow-layer buoyancy/moisture should be
greatest), and isolated severe gusts. Strong veering of winds with
height will lead to a long, somewhat hook-shaped low-level hodograph
with small near-surface SRH, but strong total shear and deep shear (effective-shear magnitudes 50-60 kt over western SD decreasing to
40-50 kt farther north). Buoyancy also will be favorable in this
corridor, but decreasing northward, with MLCAPE ranging from the
2000-3000 J/kg range near the moist axis just north of the Black
Hills, to less than 1000 J/kg near the international border.
Convection should diminish this evening as inflow-layer instability
weakens.

...Northeastern CONUS...
The remnants of an MCS, that produced several measured severe gusts
and numerous damage reports in the southern Upper Great Lakes region
overnight, appear to be weakening while moving into a more-stable
environment in western/central PA.

Rejuvenation of this activity -- or additional development in the
associated plume of relatively maximized deep-layer ascent preceding
the shortwave trough -- will lead to a ramping up of severe
potential from midday into this afternoon across much of the
Northeast. A favorably moist and diurnally destabilizing airmass
will support thunderstorm development from this regime southward
over the eastern parts of the higher terrain, and the Piedmont, with
occasional damaging gusts as the main threat.

...AZ...
Widely scattered thunderstorms may develop this afternoon over
higher terrain north through southwest of TUS, shifting westward to southwestward across lower deserts of southern AZ. Isolated severe
gusts will be the main concern. A deep layer of easterlies from
about 700 mb to the max parcel level will encourage this activity
out of the mountains and over hot, deeply mixed, lower-elevation
boundary layers. Just enough moisture may remain through the mixing
process to support 200-800 J/kg MLCAPE above, and 2-3 times that
much DCAPE. With modest buoyancy, the longevity and organization of
the potential is in question, so the severe threat remains at an
unconditional marginal level.

..Edwards/Broyles.. 07/29/2023

$$
--- SBBSecho 3.14-Linux
* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 031250
SWODY1
SPC AC 031248

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Thu Aug 03 2023

Valid 031300Z - 041200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL GREAT PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK...AS WELL AS OVER PORTIONS OF THE TENNESSEE VALLEY
REGION...

...SUMMARY...
The most concentrated and intense severe threat, today into this
evening, will be for thunderstorm gusts across parts of the central
Great Plains.

...Synopsis...
The dominant synoptic- to large-scale upper-air feature for this
period will remain a persistent high over central/east TX, which is
forecast to drift southward over that region through this period. A
mean ridge will continue to extend from there northwestward across
the central/northern High Plains to portions of SK, but will be
penetrated by a few shortwave troughs of varying amplitudes. The
most prominent of those perturbations is apparent in moisture-
channel imagery over UT, and forecast to pivot northeastward then
eastward across WY toward the Black Hills through 12Z tomorrow. A
weaker, but at least as influential shortwave trough is evident over
the San Juan Mountains, and should move slowly northeastward over CO
today. This trough's midlevel vorticity field should be
convectively reinforced tonight across KS -- perhaps in the form of
a distinct MCV.

Farther north and east, a mean trough will persist from QC southward
across or just east of the U.S. East Coast. In the trailing
northwest flow, a shortwave trough now over northwestern ON -- near
Lake Superior -- will move over the Lower Great Lakes during the
03-09Z time frame, then pivot northeastward and weaken somewhat.

At the surface, 11Z analysis showed a low near STL, with warm front southeastward across central KY and mid/eastern TN to northeastern
GA. A stationary front was drawn from the STL low west-
southwestward across central KS to another low near DDC, with a weak
cold front southwestward over northern NM. The eastern low should
move eastward across KY today, while the trailing frontal segment
sags southward over western KY/southern MO, largely behind an area
of convective outflow over parts of the Tennessee Valley region.
The front should move slowly southward over KS, then into northern
OK overnight, with a parallel low-level moisture axis/plume to its
immediate north across KS.

...Central Plains...
Widely scattered to scattered thunderstorms are expected to form
this afternoon on the eastern slopes of the Front and Laramie Ranges
and move eastward across the adjoining High Plains. Large hail and
damaging gusts each will be threats in the first few hours. With
time, activity should consolidate into a quasi-linear band of
outflow-dominant thunderstorms, producing swaths of severe wind.
The greatest potential concentration and intensity of the wind
threat appears to be either side of the I-70 corridor from eastern
Co into western KS, perhaps as far north as I-80 in portions of
southwestern NE, with the southern part encountering greater
buoyancy and lasting longer. The 30%/enhanced wind area has been
expanded eastward somewhat to account for forward-propagational,
cold-pool driven potential for severe gusts this evening.

Activity should develop as large-scale ascent aloft -- immediately
preceding the ridge-penetrating shortwave trough(s) -- times well to
move atop a diurnally heated/destabilizing and favorably moist
boundary layer from the foothills eastward. A deep, well-mixed
boundary layer across eastern CO should foster strong-severe gusts
relatively early in the convective cycle, in addition to supporting
survival of hailstones to the ground. A moist axis and easterly
surface-wind component will be present across eastern CO and much of
KS, with favorable storm-relative winds for an accelerating MCS this
evening. Preconvective MLCAPE should range from around 1500-2000
J/kg over eastern CO to 2500-3500 J/kg over central KS, though
MLCINH also will increase with eastward extent and time, requiring
more forced/cold-pool-driven ascent to maintain the convection at
severe levels. Additional, isolated to widely scattered
thunderstorms also may develop ahead of the MCS and north of the
front this evening, near the surface moist axis, posing a threat for
isolated severe hail and/or gusts from eastern KS into parts of MO.

...Parts of the TN Valley/Southeast...
Scattered thunderstorms are expected to cross this region today from northwest-southeast -- generally following the ambient flow west of
the mean mid/upper trough, as well as a net baroclinic zone
southwest of the synoptic warm front related to successive
convective outflows. While some timing uncertainty remains, the
activity over this region will have the potential to produce
damaging to severe gusts. The tornado threat is very conditional,
tied mainly to storm-boundary interactions on or near the main
baroclinic corridor.

An ongoing band of strong thunderstorms across northwestern TN may
be an early manifestation of the day's severe threat farther
southeast, if it can last long enough for the foregoing air mass to
diurnally destabilize favorable. See SPC mesoscale discussion 1819
for near-term/nowcast details. Whether ahead of this or later
activity developing on its outflow-reinforced boundary, the severe
threat will be supported by rich low-level moisture, with surface
dewpoints in the upper 60s to mid 70s F being widespread from the
boundary southward to the Gulf Coast. That, along with strong
heating and a deep troposphere, should offset modest midlevel lapse
rates to drive MLCAPE into the 2500-4000 J/kg range on the warm
(southwest) side of the boundary. Low-midlevel winds and shear will
be weak, suggesting multicellular clusters will be the predominant
mode, with some upscale/cold-pool growth possible.

...Parts of lower MI into NY...
The extent of destabilization later today over NY is uncertain --
behind ongoing cloud/precip. Still, sufficient boundary-layer
heating and large-scale lift should occur ahead of the Canadian
shortwave trough to support additional development with a primary
damaging-wind concern. Although most progs reasonably indicate
greater buoyancy over Canada, a plume of minimally inhibited,
1000-1500 J/kg MLCAPE may develop across eastern Lower MI and
northern NY, supporting convective potential along/ahead of a cold
front preceding the trough aloft. The greatest unconditional threat
across the U.S. part of the region appears to be over parts of
northern NY, where relatively concentrated/focused activity at
severe levels may move across from southern QC this evening. Modest
and nearly unidirectional low/middle-level wind profiles will keep
effective shear weak, though strong upper-level flow will aid in
convective organization. Potential becomes more isolated and
conditional farther south in upstate NY, as well as over Lower MI.

..Edwards/Broyles.. 08/03/2023

$$
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* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 091251
SWODY1
SPC AC 091249

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Wed Aug 09 2023

Valid 091300Z - 101200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OZARKS TO THE
TN VALLEY...

...SUMMARY...
Multiple rounds of significant severe thunderstorms with tornadoes,
and damaging winds/hail are possible from the Ozarks to the
Tennessee Valley this afternoon into tonight.

...Ozarks to the TN Valley...
A complex severe weather scenario is anticipated through tonight
with multiple rounds of intense severe thunderstorms possible.
Within a high ceiling but low floor setup, the middle risk level (3
of 5) remains appropriate given the degree of uncertainty/failure
modes at this outlook cycle. Primary adjustments are to add
significant severe areas across the hazards to indicate the
potential of a higher-end outcome.

Extensive elevated convection is ongoing across parts of the Ozarks
to an MCV evident in east KS. This activity may decay somewhat but
will likely persist through midday amid a robust low-level warm
theta-e advection regime downstream of the primary shortwave trough
over the central High Plains. Along the southern extent of this
regime, convection may transition to becoming surface-based over
parts of the Mid-South towards midday as the leading edge of mid 70s
surface dew points advects northeast from the Ark-La-Miss. CAM
guidance consensus suggests potential for relatively pronounced 2-5
km UH within a favorable wind profile for mid-level updraft
rotation. Significant severe hail should be the primary initial
threat with discrete supercells along the leading edge of steep
mid-level lapse rates. Damaging winds and a couple tornadoes will
also be possible as activity congeals into clusters across the TN
Valley through the afternoon.

A second round of severe thunderstorms should develop near/ahead of
the surface cold front/inverted trough across parts of central to
southern MO into eastern OK during the late afternoon. Guidance
depicts wide variation in the northern extent of air mass recovery
today along the trailing outflow/differential heating corridor. The
gradient across the baroclinic zone will be quite pronounced owing
to hot temperatures across TX into southern OK exceeding 100 F
versus low 70s holding in parts of MO. Deep-layer shear vectors will
be at least semi-orthogonal to the initiating front and should
support initially discrete supercells amid 45-60 kt effective bulk
shear. Strengthening low-level southwesterlies during the evening
will further enlarge hodograph curvature across southern MO and
northern AR. This could foster potential for a couple strong
tornadoes, but will likely be highly dependent on the evolution of
the low-level thermodynamic fields in the wake of earlier
convection.

ARW-based CAMs and the 06Z RRFS are insistent on prominent upscale
growth occurring tonight as low to mid-level flow fields strengthen
ahead of the aforementioned shortwave trough tracking towards the
Mid-MS Valley. This should result in an MCS tracking southeast along
the baroclinic zone trailing northwest in the wake of the early-day
storms. The spatial extent and amplitude of severe wind gusts will
be modulated by cold pools from prior convection and background
nocturnal stabilization to some degree. But given 65-80 kt
rear-inflow low-level winds depicted in forecast soundings, there is conditional potential for a more widespread damaging wind threat
with embedded significant severe surface gusts and QLCS tornadoes
amid bowing structures/mesovortices.

...U.P. of MI to the eastern Dakotas...
Isolated thunderstorms developing along a diffuse cold front will
mature in an environment with only modest buoyancy (MLCAPE between
500-1000 J/kg), but effective shear values between 30-35 knots.
Given storm motions and deep-layer shear vectors largely off the
front, discrete to semi-discrete storms appear probable. A similar
environment yesterday supported isolated severe storms, and this
should be the case again today farther south and in a bit wider
corridor over the Upper Midwest.

..Grams/Dean.. 08/09/2023

$$
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ACUS01 KWNS 301628
SWODY1
SPC AC 301626

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1126 AM CDT Wed Aug 30 2023

Valid 301630Z - 311200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
FOR COASTAL SC AND SOUTHERN COASTAL NC...

...SUMMARY...
A few tornadoes are expected through tonight from southeast Georgia
into the coastal Carolinas in association with Hurricane Idalia.

...Southeast Atlantic coast through tonight...
The weakening remnants of Hurricane Idalia are forecast to continue
moving northeastward near the southeast Atlantic coast through
tonight (see latest NHC advisories for additional information).
Flow will continue to veer and weaken across central/north FL and
the tornado threat will likewise diminish through the afternoon.
Farther north, more backed low-level flow and larger, curved
hodographs (effective SRH 300-400 m2/s2) are expected in advance of
Idalia's core across some of southeast GA and coastal SC this
afternoon. Inland rainfall will reinforce a coastal baroclinic zone
which will help focus the tornado threat near and just inland from
the coast where surface-based buoyancy will be largest, as outer
rain band supercells move inland. A similar environment and
attendant tornado threat will spread northeastward across coastal NC
late this afternoon through tonight.

...New England this afternoon...
A pronounced midlevel trough will move over New England this
afternoon along with an associated surface cold front. There will
be a narrow zone of destabilization along the front, where weak
bands of convection will be possible with a very low chance of wind
damage given the moderately strong midlevel flow. However, will not
add an outlook area since the window of opportunity will be small
and confidence in storm development is relatively low.

...Eastern MT/western ND this afternoon/evening...
A midlevel shortwave trough will progress eastward from the northern
Rockies to the northern High Plains, and this midlevel trough will
be preceded by a surface trough/cold front. Some high-based
convection could occur along the front in the limited-moisture
environment, and this convection could produce gusty outflow winds.
The chance for severe outflow winds appears relatively low,
precluding the need for an outlook area.

..Thompson/Lyons.. 08/30/2023

$$
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* Origin: Ilink: CCO - capitolcityonline.net (454:1/105)

ACUS01 KWNS 031237
SWODY1
SPC AC 031236

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0736 AM CDT Tue Oct 03 2023

Valid 031300Z - 041200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
INTO EARLY TONIGHT FROM WESTERN/CENTRAL KS INTO SOUTH CENTRAL NE...

...SUMMARY...
Isolated very large hail, occasional severe gusts and a few
tornadoes will be possible this afternoon through early tonight
across parts of the Great Plains.

...Synopsis...
A surface cyclone in ND will develop northeastward today toward
southeast SK/western ON as an associated/lead shortwave trough
ejects northeastward over the northern Plains. A trailing shortwave
trough near the Four Corners will progress east-northeastward over
the central Plains later this afternoon through early tonight, with
weak lee cyclogenesis is expected near the CO/KS border today. A
surface cold front will move eastward/southeastward across the
Dakotas, western NE and northeast CO this afternoon, in the wake of
the ND cyclone (and north of the weak lee cyclone). South of the
weak lee cyclone, a dryline will mix eastward into southwest KS and
the western TX Panhandle by mid afternoon. The front and the
dryline will help focus severe thunderstorm development, primarily
this afternoon/evening from NE/KS into west TX.

...Central/southern Plains through tonight...
A narrow corridor of low-mid 60s boundary-layer dewpoints will
spread northward today to the east of a sharpening dryline, and in
the wake of scattered morning convection that is ongoing from
western KS to the TX South Plains. Surface heating along the moist
axis, beneath midlevel lapse rates greater than 7 C/km, will result
in afternoon MLCAPE values of 1500-2500 J/kg with weakening
convective inhibition. Initial severe storm development may occur
by about 20z across KS/NE, with subsequent expansion of the storms northeastward across NE toward southeast SD, with more scattered
development southward along the dryline toward TX. Long hodographs
(effective bulk shear ranging from 45 kt across west TX to 65 kt
closer to the KS/NE border) with the moderate buoyancy will favor
supercells initially, with the potential to produce isolated very
large hail up to 2.5 inches in diameter. Some upscale growth into
line segments is anticipated from northern KS into NE as storms
align along the cold front. The tornado threat will be modulated by
rather modest hodograph curvature/SRH through much of the afternoon
where the more discrete supercells are expected, and any evening
increase in low-level shear will be somewhat countered by the
tendency for more linear convective modes with northward extent.

Farther south into west TX, weaker forcing for ascent suggests that
storm coverage will be widely scattered along the dryline. Still,
there will be sufficient vertical shear/buoyancy for splitting
supercells capable of producing large hail/isolated wind damage late
this afternoon through late evening.

..Thompson.. 10/03/2023

$$
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ACUS01 KWNS 041631
SWODY1
SPC AC 041630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Wed Oct 04 2023

Valid 041630Z - 051200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PARTS OF
NORTHWEST/NORTH TX AND SOUTHWEST/SOUTH-CENTRAL OK...

...SUMMARY...
Scattered to numerous severe thunderstorms are expected through
early morning across parts of the southern Great Plains.
Destructive, very large hail and significant severe wind gusts will
be the main threats, along with possibly a couple tornadoes.

...Southern Great Plains...
Confidence continues to increase with potential for a significant
severe weather episode across north/west TX and south OK this
afternoon into tonight, yielding expansion of the cat 3 severe risk.

The northern extent of a rather rich western Gulf air mass has
spread across much of north TX and southwest to east OK,
characterized by upper 60s to low 70s surface dew points. Moderate boundary-layer heating coupled with the rich moisture will yield a
broad plume of 2000-3000 J/kg MLCAPE by late afternoon. Elevated
thunderstorms may continue to shift east into northeast OK while
renewed development across the TX Panhandle will probably intensify
by early afternoon as it transitions to surface-based development
along the southward-sagging composite cold front/large-scale
outflow. Scattered thunderstorm development is also anticipated
southward into the Trans-Pecos as low-level convergence/upslope
increases near the dryline.

A lack of surface cyclogenesis will result in relatively weak
low-level mass response and correspondingly small low-level
hodographs this afternoon in the warm sector. However, substantial
speed shear above 700 mb will yield relatively straight and highly
elongated mid to upper-level hodographs favoring splitting
supercells with initial storm development. These initial supercells
will be capable of producing very large to giant hail from 2-3.5
inches, mainly across west TX where steeper mid-level lapse rates
and discrete supercell mode will persist longer.

Farther north and east, consolidating outflow interactions and
minimal convective inhibition will likely result in quicker upscale
growth into clusters and bowing line segments by late
afternoon/early evening as storm coverage becomes widespread. Still,
given the favorable hodographs for strong mid-level rotation,
longer-track embedded supercells will be possible, especially along
the composite front/outflow across south OK initially, and over
western north TX later. These may yield destructive wind-driven hail
swaths with localized gusts reaching 75-85 mph. A large MCS is
anticipated this evening, moving east-southeast over north/northeast
TX with a decreasing severe wind risk overnight.

..Grams/Bentley.. 10/04/2023

$$
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