ACUS01 KWNS 171948
SWODY1
SPC AC 171946

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0146 PM CST Sun Dec 17 2023

Valid 172000Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
NORTH CAROLINA AND THE OUTER BANKS...

CORRECTED FOR TYPO

...SUMMARY...
Isolated damaging gusts and a couple of tornadoes will be possible
through tonight across coastal North Carolina and the Outer Banks.

...20z Update...

A damaging wind and tornado risk will continue into the evening
across the North Carolina coast and Outer Banks. A few stronger
cells interacting with the baroclinic zone along the coast have
shown rotation, with a possible tornado observed via radar earlier
this afternoon near the SC/NC border. While cloud cover, widespread precipitation and poor lapse rates will limit instability, strong
low-level vertical wind profiles will remain favorable for damaging
gusts and a couple of tornadoes. The only change with the 20z update
was to trim severe probabilities from most of South Carolina in the
wake of the surface low and primary surface trough. General thunder
was also removed on the western periphery of the outlook area,
mainly from GA and upstate SC.

..Leitman.. 12/17/2023

.PREV DISCUSSION... /ISSUED 1028 AM CST Sun Dec 17 2023/

...Discussion...
Recent surface analysis shows a low just off the northeastern Florida/southeastern Georgia coast at this time, which is progged to
steadily deepen while shifting north-northeastward through tonight.
At this time, what appears to be the most likely track for the low
will be to remain just off the South Carolina coast through the
daytime hours, and then possibly move just inland across coastal
North Carolina or the Outer Banks overnight.

North of the low track, widespread/steady precipitation is ongoing,
which should reinforce a persistent cool/stable boundary layer
inland through the daytime hours. With that said, the favorably
strong/veering wind field observed within the northeast quadrant of
the low continues to support occasionally rotating cells just
offshore. This will continue, along with gradually increasing
potential that a couple of these cells will begin moving inland
across South Carolina coastal counties northeast of Charleston.
While any storms would become increasingly elevated along their
inland advance, storms may remain rooted near enough to the surface
across immediate coastal counties of northeastern South Carolina --
and then later over eastern North Carolina and in particular the
Outer Banks -- to yield risk for a couple of tornadoes, and possibly
locally damaging wind gusts. As such, will maintain current
delineation of the SLGT risk area just inland across South Carolina
for today, and then across eastern North Carolina and the Outer
Banks area for this evening and overnight.

$$

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ACUS01 KWNS 130056
SWODY1
SPC AC 130055

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0655 PM CST Mon Feb 12 2024

Valid 130100Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
TN/NORTHEAST GA THROUGH THE CAROLINAS...

CORRECTED FOR INCORRECT DAY REFERENCE IN TEXT

...SUMMARY...
Isolated wind damage and a tornado or two will be possible,
primarily across the coastal Carolinas overnight.

...01Z Update...

...Eastern TN/Northeast GA through the Carolinas...
A strongly forced, shallow convective line continues to push
eastward across eastern TN and western GA, forced by strong ascent
attendant to the eastward-moving shortwave currently over the
Mid-South. This line is forecast to continue eastward this evening
and overnight, moving across Carolinas and offshore by early
Tuesday. Buoyancy ahead of the line will remain limited, but a few
convectively augmented gusts are still possible across this region
this evening and overnight

Current surface observation place the 60 deg F dewpoints over
southern GA. There is some potential for this better low-level
moisture to advect northward into the coastal portions of the
Carolinas, augmented by some advection off the Atlantic as well.
This could help foster modest buoyancy ahead of the approaching
convective line, contributing to a greater chance for deeper
updrafts and near-surface-based storms capable of a few damaging
gusts and maybe even a brief tornado.

..Mosier.. 02/13/2024

$$

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ACUS01 KWNS 221419
SWODY1
SPC AC 221418

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0818 AM CST Thu Feb 22 2024

Valid 221300Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE MID-SOUTH REGION...

CORRECTED FOR TYPO

...SUMMARY...
Thunderstorms may produce marginally severe gusts or hail this
afternoon and evening over parts of the Mid-South region.

...Synopsis...
In the mean, mid/upper-level pattern amplification should begin
again during this period, as ridging builds over NV, the Pacific
Coast States and interior Northwest. Downstream, a series of
shortwaves will contribute to substantial synoptic-scale height
falls over much of the Mississippi and Ohio Valleys to the central
Gulf Coast. None of those perturbations -- including some apparent
in moisture-channel imagery over OK, northern KS/NE, and western CO
-- are (or will become) particularly intense, but should contribute
to at least weak large-scale destabilization aloft and maintenance
or strengthening of cyclonic flow.

At the surface, 11Z analysis showed a cold front extending from a
low over southeastern ON across northern IN, through weak lows over
central MO and near TUL, then across northwest TX to southern NM.
The front should move eastward and southeastward today, to a 00Z
position over eastern/southern OH, the lowest Ohio Valley, eastern/
southern AR, and northeast to south-central TX. By 12Z, the front
should reach central NY, eastern PA, the southern Appalachians,
central parts of MS/LA, and shelf waters of the northwestern Gulf.

...Mid-South region...
Isolated to widely scattered thunderstorms are expected to develop
by late this afternoon along/ahead of the cold front, over central/
eastern AR and perhaps western TN. Activity should strengthen and
increase in coverage through evening as it encounters greater
moisture across the Mississippi Valley and into northern portions of
MS tonight. Some upscale organization into a short QLCS is possible
from early multicell to supercell modes. Marginally severe hail and
damaging gusts will be the main concerns.

The outlook area will reside on the southwestern rim of a far larger
swath of general thunderstorm potential, but with access to
sustained, effectively surface-based and at least marginally moist
inflow parcels beginning mid/late afternoon in AR and shifting east- southeastward with time. Progs that generate little substantial
convection generally are too cool at the surface. Forecast max
surface temperatures in the mid/upper 60s F over much of the area
will support favorable low-level lapse rates, as well as some
boundary-layer mixing, amidst potential for localized downward
momentum transfer from stronger flow aloft, for gust support.

Midlevel lapse rates are not expected to be very strong, limiting
MLCAPE to around 250-750 J/kg, and likely keeping the hail potential
isolated, marginal and conditional to supercell maturation.
Sufficient deep shear will exist for that, however, with modified
forecast soundings indicating around 40-45-kt effective-shear
magnitudes and 150-250 J/kg effective SRH -- despite prefrontal
veering with time of surface winds toward southwesterly. Greater
diurnal boundary-layer mixing/drying, EML-related CINH and weaker
CAPE will likely restrict severe potential around western parts of
the outlook, while instability decreases northward, moisture
decreases eastward, and lift weakens southward.

..Edwards.. 02/22/2024

$$

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ACUS01 KWNS 030557
SWODY1
SPC AC 030555

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1155 PM CST Sat Mar 02 2024

Valid 031200Z - 041200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
FLORIDA PENINSULA...

CORRECTED FOR THUNDER LINES

...SUMMARY...
A few strong thunderstorms will be possible across parts of Florida
during the afternoon and early evening. Isolated hail is expected to
be the primary threat, though locally gusty winds may also occur.

...Synopsis...
A deep upper-level trough will persist over the western CONUS
through the period, as a strong embedded shortwave moves from the
central High Plains toward the upper Great Lakes region. A surface
low attendant to this shortwave will move northward across the
Dakotas and Minnesota, with secondary cyclogenesis expected over the
central High Plains during the afternoon/evening. Farther east, a
weak upper-level trough will move slowly eastward across parts of
the Southeast, to the south of a building upper ridge across the Mid Atlantic/Northeast.

...Florida...
Moderate buoyancy (MLCAPE of 1000-1500 J/kg) will likely develop
during the afternoon across much of the FL Peninsula, resulting from
seasonably strong diurnal heating of a relatively moist low-level
environment. Diminishing MLCINH will support scattered thunderstorm development, especially in association with sea-breeze circulations
and possibly near any other boundaries left over from
overnight/early-morning convection.

Very weak low-level flow and only modest deep-layer flow/shear will
tend to limit storm organization and longevity, but storm
interactions and locally enhanced shear near the sea breezes could
yield a couple stronger multicells and perhaps a marginal supercell.
With relatively cold temperatures aloft (-13C to -16C at 500 mb)
associated with the upper trough, the strongest storms could pose an
isolated hail threat. Locally gusty winds will also be possible,
though the severe-wind threat appears relatively limited due to very
weak low-level flow and limited potential for organized upscale
growth.

..Dean/Weinman.. 03/03/2024

$$

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ACUS01 KWNS 042204
SWODY1
SPC AC 042203

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0403 PM CST Mon Mar 04 2024

Valid 042000Z - 051200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A LARGE
AREA FROM CENTRAL/EAST TEXAS INTO MOST OF THE MISSISSIPPI VALLEY...

CORRECTED FOR TYPO

...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.

...20Z Update...

...Eastern IA/Northern MO/Northern IL...
Recent surface analysis places a low just south of the IL/WI/IA
border intersection. A cold front extends southwestward from this
low across northern MO and eastern KS, while a warm front extends
eastward across northern IL and then arcs sharply northeastward over
southern Lake Michigan. A few elevated storms have been noted near
the surface low, with some deepening warm sector cumulus also
ongoing from central MO into northern/central IL. As mentioned in
MCD #0189, additional thunderstorm development is still expected
along and just ahead of cold front from far eastern IA into
northwest Illinois and northeast Missouri in the next 1-3 hours.
Front-parallel orientation to the deep-layer vertical shear will
likely lead to an undercutting of these storms, with a predominantly
elevated storm mode anticipated. Even so, steep lapse rates will
support some stronger updrafts capable of hail. Some damaging gusts
are possible as well, particularly as cells interact with the cold
front.

...East TX/LA/Western MS this afternoon and evening...
Scattered thunderstorms are currently ongoing from East TX across
much of LA, supported by southwesterly flow aloft and resultant
warm-air advection. General expectation is for these storms to
gradually shift northeastward into more of western MS over time, in
tandem with the zone of most favorable warm-air advection. Modest
vertical shear remains favorable for transient supercell structures
and the threat for hail and damaging gusts.

...Eastern OK into Mid MS Valley this evening and overnight...
Thunderstorm development along the front later this evening along
the from southern MO into eastern OK remains uncertain, given the
potential for warm mid-level temperatures and resulting capping.
Additionally, vertical shear will be modest, with a resultant
potential for the front to undercutting development. Even so, the
warm and moist low-levels combined with steep mid-level lapse rates
will support a conditional risk for severe hail.

..Mosier.. 03/04/2024

.PREV DISCUSSION... /ISSUED 1000 AM CST Mon Mar 04 2024/

...East TX/LA/Western MS Today...
Moderately strong southern-stream mid-level flow is present today
across the southern states, with several weak perturbations
affecting the area. A warm and moist surface air mass is in place
across east TX into LA, where dewpoints in the upper 60s and 70s
will yield afternoon MLCAPE of 1500-2000 J/kg. Weak low-level warm
advection is expected to result in increasing thunderstorm
development this morning through the afternoon as storms spread
eastward toward southwest MS. Deep-layer shear is sufficient for at
least transient supercell structures, but relatively weak low-level
winds suggest the main threats will be hail and gusty winds with the
strongest cells.

...Eastern IA/Northern MO/Northern IL...
A strong surface cold front is sagging southeastward across IA this
morning into a marginally moist and unstable air mass. All 12z
model guidance agrees on the development of showers and
thunderstorms along the front by early afternoon, although many
solutions suggest most of the activity will be behind the front and
slightly elevated. Nevertheless, cool temperatures aloft and steep
mid-level lapse rates will promote hail in the stronger cores.
Storms that can form and persist ahead of the front would have some
marginal concern for gusty winds and perhaps a brief tornado as
well.

...Eastern OK into Mid MS Valley...
Morning model guidance is quite diverse in the development of
thunderstorms across this region, with low confidence in any
particular area. Will maintain the ongoing MRGL area as a
conditional risk if storms can form - mainly due to unseasonably
warm and moist conditions and sufficient CAPE for some risk of hail.
However, considerably uncertainty exists.

$$

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ACUS01 KWNS 071721
SWODY1
SPC AC 071720

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1120 AM CST Thu Mar 07 2024

Valid 071630Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS...

CORRECTED FOR WEB GRAPHICS ERRORS

...SUMMARY...
Severe thunderstorms are possible over parts of the southern Plains
this afternoon into tonight.

...Synopsis...
An upper trough is deepening across the Four Corners region today,
with fast mid/high level flow extending across northern Mexico into
TX. Beneath this fast zonal flow regime, southerly low-level winds
are helping to advect/maintain upper 50s and 60s dewpoints over much
of TX and southern OK. Widespread cloud cover this morning will
continue to suppress strong heating except across western OK and
west-central TX where a dryline will develop. This will lead to
multiple mesoscale areas of concern for strong/severe thunderstorm
development this afternoon and evening.

...Central TX...
An area of residual precipitation is affecting north-central TX.
The outflow boundary along the southern edge of this convection will
likely become the focus for intensifying storms later today. Strong
flow aloft will promote supercell structures, with very large hail
possible in the initial activity. Storms that can maintain discrete
nature may also pose some tornado risk this evening as southerly
low-level winds and shear increase. By late evening, remaining
storms may track eastward across the SLGT risk area with a threat of
damaging wind gusts.

...Western/Central OK...
Isolated supercell storms are expected to form along the diffuse
dryline over western OK and western north TX. This activity may
produce very large hail initially, but an evolution to more linear
structures is expected during the early evening, with hail and
damaging winds possible.

...Southeast KS/Southwest MO...
Dense cloud cover over this region is expected to erode by mid
afternoon, allowing some daytime heating and destabilization along a
surface boundary extending across eastern KS into western MO. This
zone will likely be the focus for scattered afternoon thunderstorms.
Despite rather weak instability, shear profiles would support
supercell structures capable of all severe hazards for several hours
through early evening.

..Hart.. 03/07/2024

$$

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ACUS01 KWNS 121645
SWODY1
SPC AC 121643

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1143 AM CDT Fri Apr 12 2024

Valid 121630Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF EASTERN NEW YORK/WESTERN NEW ENGLAND...AND FROM NORTHERN NEVADA
TO WESTERN MONTANA...

CORRECTED TO REMOVE LESS THAN 2% TORNADO TEXT FROM THE PROBABILITY
GRAPHIC

...SUMMARY...
Isolated severe wind gusts and hail may occur with thunderstorms
over northern Nevada, eastern Oregon, Idaho, and far western Montana
late this afternoon and early evening.

...Champlain/Hudson Valleys of New York into western New England...
Showers appear to be increasing at this time across the
Hudson/Champlain Valleys, ahead of an occluded front moving eastward
across eastern portions of Upstate New York early this afternoon. A
lobe of vorticity will continue rotating northeastward across the
region this afternoon, on the eastern fringe of the upper low
crossing the Great Lakes. Cold air aloft combined with weak
insolation through breaks in the cloud cover evident in visible
satellite imagery will permit additional/modest destabilization. As
a result, low-topped thunderstorms are expected to develop across
this area.

With deep-layer flow somewhat unidirectional/meridional, but
strengthening with height, shear will support organized storms and
potentially a few rotating updrafts. As a result, a brief/weak
tornado or two will be possible, along with gusty winds that may
approach severe levels locally, with a few stronger cells and/or
line segments. As such, a MRGL risk is being introduced across a
portion of eastern New York and into parts of western New England.
For additional short-term information, please refer to SWOMCD #429.

...Parts of northern Nevada to western Montana...
Ahead of the advancing upper low, daytime heating beneath steep
mid-level lapse rates will result in modest destabilization, with
degree of CAPE hindered due to scant moisture availability across
this region. Still, with a few hundred J/kg mixed-layer CAPE likely
by late afternoon, widely scattered thunderstorms are expected to
develop.

With favorably strong flow aloft across this area, a few
stronger/sustained updrafts appear likely. With a very deep
well-mixed boundary layer expected across the region, gusty
downdraft winds -- enhanced due to evaporative cooling in the
sub-cloud layer -- may reach severe levels in a few instances. This
warrants continuation of the MRGL risk across into early evening.

...Ohio Valley to the Mid-Atlantic region...
Scattered showers should diurnally increase from parts of the OH
Valley across the central Appalachians to the Virginia/North
Carolina area, with eventual/embedded low-topped thunderstorms
expected to develop within the broader area of precipitation this
afternoon.

The convection will be associated with cold mid-level temperatures
accompanying a shortwave trough, that is embedded within the broader
cyclonic circulation across the eastern CONUS. With generally west-northwesterly flow behind the cold front, instability should
remain very weak. Still, enhanced low-level winds may reach the
surface given the anticipated well-mixed boundary layer, resulting
in occasional strong/gusty winds with a few of the stronger
convective elements.

..Goss/Bentley.. 04/12/2024

$$

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ACUS01 KWNS 261644
SWODY1
SPC AC 261642

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1142 AM CDT Fri Apr 26 2024

Valid 261630Z - 271200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING FROM EASTERN NEBRASKA/WESTERN IOWA SOUTHWARD TO EASTERN
OKLAHOMA AND NORTHEAST TEXAS...

CORRECTED FOR WEB GRAPHICS ERROR

...SUMMARY...
A few tornadoes, including a couple of strong tornadoes, isolated
very large hail (greater than 2 inch diameter) and isolated wind
damage will be possible, mainly this afternoon/evening from
northeast Kansas/southeast Nebraska into western Missouri, eastern
Oklahoma, western Arkansas, and northeast Texas.

...NE/IA/MO/KS...
Water vapor loop shows a strong shortwave trough rotating across
KS/NE. A deep surface low is analyzed ahead of this trough over
central NE, with a dryline extending southward into central KS. A
corridor of ample low-level moisture is present ahead of the dryline
over southeast NE/northeast KS, where daytime heating will lead to
moderate MLCAPE values and rapid thunderstorm development by
mid-afternoon. Backed low-level winds and favorable shear profiles
will promote supercells in the bent-back region of the low, with
very large hail and tornadoes possible. These storms will progress
eastward into western IA and northwest MO through the early evening.
A strong tornado or two is possible in this region.

...OK/MO/AR...
A large nocturnal MCS that affected much of OK has quickly weakened
and departed, with rapid northward return of low-level moisture
occurring in the wake of the system. By mid-afternoon, mid-upper
60s dewpoints are expected along the dryline over east-central OK.
Forecast soundings show very steep mid-level lapse rates and
favorable shear profiles to promote discrete supercells capable of
all severe hazards, including very large hail and strong tornadoes.
Storms will track northeastward into southwest MO and northwest AR
this evening. CAM guidance varies on coverage of storms, but
parameters appear quite strong and warrant an upgrade to ENH given
the conditional risk of significant severe weather.

...Northeast TX...
A third area of significant risk of severe storms lies across parts
of northeast and east-central TX today. A cluster of
severe/supercell storms has formed this morning to the west of Waco,
TX. These storms are expected to increase in coverage through the
afternoon and develop eastward across much of northeast TX.
Forecast soundings show a very moist and unstable environment, with
sufficient low-level and deep-layer shear for persistent supercell
structures and risks of a few tornadoes and very large hail. Given
the number of storms and the favorable environment, have also
upgraded this narrow corridor to ENH.

..Hart.. 04/26/2024

$$

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ACUS01 KWNS 270754
SWODY1
SPC AC 270753

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0253 AM CDT Sat Apr 27 2024

Valid 271200Z - 281200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH TEXAS...OKLAHOMA...SOUTHEAST KANSAS AND FAR SOUTHWEST
MISSOURI...

CORRECTED FOR GEOGRAPHIC REFERENCE IN MISSOURI

...SUMMARY...
Numerous severe thunderstorms are likely today and tonight across
the southern and central Plains into the lower to mid Missouri
Valley. The greatest potential for severe storms will be from north
Texas into Oklahoma and southeast Kansas, where strong tornadoes,
very large hail over 2 inches in diameter and widespread damaging
winds (some over 70 mph), are expected to occur. A broader area of
severe threat will extend from south-central Texas
north-northeastward to the Great Lakes.

...Tornado Outbreak Expected Today From North Texas into
Oklahoma...Southeast Kansas and Far Southwest Missouri...

...Southern Plains...
An upper-level trough will move through the Desert Southwest today
as an 80 to 90 knot mid-level jet translates quickly eastward
through the base of the system. Ahead of the trough, a moist and
unstable airmass will be in place across much of the southern and
central Plains. At the surface, a low will move eastward across
southwest Kansas with a dryline extending southward through far
western Oklahoma and west Texas. Surface dewpoints to the east of
the dryline will be in the mid to upper 60s F. In response to warm
advection this morning, a cluster of thunderstorms is expected to
develop to the east of the dryline across northwest Texas. This
cluster is forecast to spread north-northeastward into western
Oklahoma by late morning. Large hail and wind damage will be likely
with the stronger cells within this cluster. An outflow boundary
with this convection should setup across west-central Oklahoma by
early afternoon, with a moist and unstable airmass extending
eastward from the boundary across much of central and eastern
Oklahoma northward into southeast Kansas. This undisturbed airmass
is expected to be favored for the greatest severe threat this
afternoon and evening.

The mid-level jet is forecast to eject quickly northeastward across
the southern Plains this afternoon. This will result in strong
deep-layer shear across most of the southern Plains, and will create
a large-scale mass response that will be very favorable for severe
storms, including supercells and bowing line segments. As the core
of the mid-level jet moves into the southern Plains during the mid
to late afternoon, a 50 to 60 knot low-level jet will rapidly
strengthen. RAP forecast sounding along and near the low-level jet
during the late afternoon look very favorable for tornadoes, with
backed surface flow, and long looping hodographs. As the low-level
jet strengthens, 0-3 km storm-relative helicity is forecast to
increase to around 400 m2/s2 across much of central and eastern
Oklahoma into southwest Missouri. The more dominant and supercells
that interact with the western and northern edge of the low-level
jet are expected to become tornadic. Several strong tornadoes will
be likely, and a few long-track EF3+ tornadoes will be possible.

In addition to the tornado threat, forecast soundings have 700-500
mb lapse rates near 8 C/km across much of the warm sector this
afternoon from north Texas to southeast Kansas. This will be
favorable for very large hail, with hailstones over 2 inches in
diameter likely with the more intense storms. Later in the evening,
a line of severe storms is expected to form, moving eastward across
eastern Oklahoma and north Texas. Wind gusts over 70 mph will be
possible with the more intense parts of the line. QLCS tornadoes
will also be possible with rotating cells embedded in the line late
this evening into the overnight period.

...Central Plains/Lower to Mid Missouri Valley...
An upper-level low will move through the southern Rockies today, as
the exit region of a mid-level jet overspreads the central Plains.
At the surface, a warm front will be located from near a surface low
in southwest Kansas east-northeastward into the mid Missouri Valley.
This front will be a focus for convective development this
afternoon. A band of severe storms is expected to form near the
front and move northward across northern Kansas into southern
Nebraska during the early to mid afternoon. RAP forecast soundings
in northeast Kansas near the front from 18Z to 21Z have MLCAPE near
3000 J/kg, 0-6 km shear around 60 knots, and steep low to mid-level
lapse rates. This environment will be very favorable for supercells
with large hail. Hailstones greater than 2 inches in diameter will
be possible with the more intense storms. In addition, forecast
soundings have 0-3 km storm-relative helicity in the 250 to 300
m2/s2 range, suggesting that tornadoes will be likely with the more
discrete supercells. A few strong tornadoes will be possible.

Further west into northwest Kansas and eastern Colorado, cold
temperatures aloft, strong large-scale ascent associated with an
upper-level low, and strong deep-layer shear will likely support
lower-topped supercells with large hail and strong wind gusts this
afternoon.

...Mid to Upper Mississippi Valley/Great Lakes...
An upper-level trough will move northeastward across the Great Lakes
region today. From near the trough, and southwestward into the mid
to upper Mississippi Valley, a wide corridor of moderate instability
will be in place by afternoon. A warm front will be in located along
the northern edge of the instability, from Iowa northeastward into south-central Wisconsin and north-central lower Michigan. As surface
heating takes place and low-level convergence increases along the
front, thunderstorms will likely form in the vicinity of the
boundary. Forecast soundings near the front at 21Z have MLCAPE
around 3000 J/kg, along with 40 knots of deep-layer shear. This
should support supercells with potential for large hail and wind
damage. The severe threat should be greatest during the late
afternoon and early evening.

..Broyles/Thornton.. 04/27/2024

$$

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