ACUS01 KWNS 261251
SWODY1
SPC AC 261250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0650 AM CST Mon Feb 26 2024

Valid 261300Z - 271200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF LOWER MICHIGAN...INDIANA...AND OHIO...

...SUMMARY...
Isolated late-night hail is possible across portions of the central
Great Lakes region.

...Synopsis...
A primarily zonal mid-level flow field in place across much of the
U.S. today will gradually amplify through tonight, as a trough digs southeastward across the northwestern quarter of the country.

As this occurs, a cold front oriented east-northeast to
west-southwest is forecast to advance southeastward across the
northern half of the Intermountain West and, later, the northern
Plains through Tuesday morning. Elsewhere, a rather nondescript
surface pattern will prevail.

...Parts of Indiana/Ohio/Lower Michigan...
As a lead/subtle mid-level short-wave trough shifts across the
Midwest tonight, some strengthening of a southwesterly low-level jet
is expected across this region. Resulting quasi-geostrophic ascent
may support development of showers and isolated thunderstorms, atop
a stable lower troposphere where steep mid-level lapse rates may
support upwards of 1000 to 1500 J/kg CAPE through the cloud-bearing
layer.

With moderately strong mid-level west-southwesterly flow
accompanying the short-wave trough, shear sufficient for mid-level
updraft rotation is evident. With that said, model guidance -- both parameterized and convection-allowing -- in general indicates
minimal overall convective development, in part due to questions
regarding potential for ample moist advection/saturation above the
inversion so as to support deep convective development. Still,
presuming a few deeper convective cells can become
organized/sustained tonight, severe-caliber hail would be possible.

..Goss/Broyles.. 02/26/2024

$$
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ACUS01 KWNS 041307
SWODY1
SPC AC 041306

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0706 AM CST Mon Mar 04 2024

Valid 041300Z - 051200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN UPPER GREAT LAKES REGION SOUTHWESTWARD TO TEXAS...AND INTO
THE LOWER MISSISSIPPI VALLEY AREA...

...SUMMARY...
Isolated strong to severe thunderstorms will be possible this
afternoon into tonight from parts of central Texas into the lower
Mississippi Valley, as well as from the Ozarks into the Midwest.
Large hail is expected to be the main threat, but strong/gusty winds
and even a tornado may also occur.

...Synopsis...
A broad area of cyclonic flow aloft will remain in place over the
western two-thirds of the country, and is expected to gradually
expand eastward with time.

As the upper troughing expands, a surface baroclinic zone extending
from the Texas Panhandle to the Upper Great Lakes will gradually
shift southeastward as a cold front, particularly during the second
half of the period. Along and ahead of this boundary, convection --
and isolated severe weather -- is expected to evolve.

...Southern Upper Great Lakes vicinity southwestward to Texas...
While weak capping should prevail across the southern Plains today,
mixing in the vicinity of a weak dryline over central Texas could
allow an isolated storm or two to develop, and possibly persist into
the evening. Given steep lapse rates aloft and deep mixed layer,
hail and/or wind exceeding severe levels could occur, in this highly conditional scenario.

More likely development of showers and thunderstorms is expected
along the surface baroclinic zone that extends northward into the
Upper Great Lakes region, perhaps beginning late this afternoon
across northern portions of the risk area and then expanding
southward along the cold front with time. With moderately strong
flow aloft atop the frontal zone across northern portions of the
risk area, a couple of stronger/rotating storms may evolve. Though
hail is expected to be the main risk given steep mid-level lapse
rates, a locally strong gust or two, or brief tornado, would also be
possible if a sustained, rotating storm can develop.

As storms develop south-southwestward into the evening and
overnight, into a region of weaker shear but steep lapse rates,
potential for hail with a few of the strongest storms is expected.
At this time, any focused areas for greater severe potential remain
difficult to discern, and thus will maintain the broad MRGL risk
area this forecast.

...Lower Mississippi Valley vicinity...
Weak QG ascent is forecast to spread into Louisiana and adjacent
Mississippi this afternoon and into this evening, as somewhat
ill-defined/weak cyclonic disturbances in the southern-stream flow
move across northern Mexico and Texas this morning, and begin
affecting the Lower Mississippi Valley area. A gradual increase in
convection through the afternoon is expected, as weak
destabilization of the moist boundary layer occurs. Some increase
in mid-level west-southwesterly flow with time will occur across
this area, as the upper disturbance(s) approach, providing ample
shear for a few stronger storms to potentially evolve. Hail would
likely remain the primary severe risk with one or two of the
strongest storms, though a stronger wind gust or even a brief
tornado cannot be ruled out given weakly veering flow with height,
and the moist boundary layer supporting surface-based updrafts.

..Goss/Broyles.. 03/04/2024

$$
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ACUS01 KWNS 121232
SWODY1
SPC AC 121231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Tue Mar 12 2024

Valid 121300Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE WESTERN OZARKS/EASTERN KANSAS REGION TO NORTHERN MISSOURI...

...SUMMARY...
Isolated severe thunderstorms are possible this afternoon and
evening from the western Ozarks/eastern Kansas region to northern
Missouri.

...Synopsis...
The period begins with a progressive, fairly low-amplitude mid/
upper-level pattern over most of the CONUS. However, a trough now
over the West Coast vicinity will strengthen as it moves inland and
reaches ID, NV and the lower Colorado River Valley by 12Z tomorrow.
This will spread a large field of height falls and generally
difluent mid/upper flow across the Great Basin, Intermountain West
and Rockies tonight, reaching the High Plains by the end of the
period. A broad area of low-end, isolated thunderstorm potential
exists ahead of the trough in the West.

Ahead of these developments, a preceding shortwave trough --
apparent in moisture-channel imagery over eastern parts of WY/CO/NM
-- will move eastward over the central Plains today. This
perturbation should reach southeasternmost NE, extreme eastern KS
and northeasternmost OK by 00Z, then cross the lower Ohio Valley
around 12Z.

At the surface, 11Z analysis showed a weak frontal-wave low over
west-central KS, south of the associated cyclonic circulation center
nearer the KS/NE border. The cyclone center and pressure low should consolidate better today as the frontal wave shifts eastward. By
00Z, the surface low should reach northwestern MO, with trailing
trough/weak cold front to northwestern OK, the northern TX
Panhandle, and southeastern CO. The low should drift eastward over
northern MO through tonight, as the trailing front/trough stall over
western OK and the eastern TX Panhandle, then begin shifting north
again in a regime of lee cyclogenesis preceding the main western
CONUS trough. A dryline -- now analyzed over Coahuila and parts of
west TX from about MAF southward, should become better defined today
from west-central TX to northeastern OK and extreme eastern KS (near
the cold front) as moist advection continues across central TX,
eastern OK, and the western Ozark Plateau.

...Ozarks/eastern KS to western/northern MO...
Isolated to widely scattered thunderstorms are possible over the
outlook area late this afternoon and/or this evening, with a
marginal large-hail and damaging-wind threat. The western part of
the outlook area is intended more for any late-afternoon development (conditional), with evening activity somewhat more certain over
eastern parts.

Moisture return will be quite immature across the region, but still
potentially sufficient for thunderstorm development, with surface
dewpoints generally reaching the mid 40s to low 50s F, east of the
dryline and south of the warm front. Cooling aloft and steepening
of low/middle-level lapse rates will occur this afternoon as DCVA
increases and low-level warm advection continues ahead of the
favorably timed shortwave trough. Boundary-layer theta-e advection
and diabatic surface heating should boost buoyancy and reduce MLCINH
throughout the afternoon, resulting in a narrow plume of about
800-1300 J/kg MLCAPE, atop a well-mixed boundary layer. Daytime
initiation, should it occur, would be between the surface moist
axis, warm front, and dryline/cold front.

Though low-level shear is expected to be favorable for supercells,
midlevel winds (generally 400-700 mb) are expected to weaken with
northward extent, closer to where low-level forcing is strongest,
near the low and frontal triple point. This will reduce effective-
shear magnitudes from around 40-50 kt in southern areas (Ozarks
vicinity) to less than 30 kt near and north of I-70. Though
convection may persist longer in that corridor this evening due to
greater instability aloft, and support from the LLJ, its
increasingly elevated inflow layer, messier mode and lack of greater
moisture will temper severe potential.

..Edwards/Dean.. 03/12/2024

$$
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