RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Mon May 4 17:56:02 UTC 2026.
No Mesoscale Discussions are in effect as of Mon May 4 17:56:02 UTC 2026.
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon May 04 2026
Valid 041630Z - 051200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
MISSOURI VALLEY INTO THE SOUTHERN GREAT LAKES...
...SUMMARY...
Scattered severe thunderstorms capable of large hail and damaging
wind gusts are possible across portions of the Midwest this
afternoon into tonight. A conditional threat for severe storms with
large to very large hail extends into portions of the
central/southern Plains.
...IL into the southern Great Lakes...
A mid-level vorticity maximum over the lower MO Valley is forecast
to move east across IL through the late afternoon and into IN-OH
tonight. An associated speed maximum at 700 mb will intensify and
overspread IL (40-50 kt) east into the southern Great Lakes while a
pronounced strengthening of 850-mb flow (50 kt) occurs during the
21-03z period. Cold mid-level temperatures (-18 deg C at 500 mb)
will act to offset initially meager moisture. Model guidance varies
considerably regarding moisture quality with ample spread amongst
different model cores/PBL schemes. However, it seems a narrow
corridor of lower to mid 50s surface dewpoints will extend
east-northeast from the lower MO Valley into the southern Great
Lakes by mid to late afternoon. Forecast soundings show weak to
moderate buoyancy (500-1250 J/kg MLCAPE). Morning model guidance
shows widely scattered to scattered storms developing within the
warm conveyor during peak heating as convective inhibition erodes.
Have expanded the Slight Risk farther east into this region to
account for a hail/wind risk with the stronger storms. Uncertainty
remains regarding quality of boundary-layer moisture across the
northern third of IN into northwest OH where hodographs become
enlarged later this afternoon into the early evening. Will
re-evaluate the tornado risk for the 20 UTC outlook if in fact
moisture quality seems sufficient for a focused, short-duration
tornado risk across the aforementioned corridor.
...Eastern KS into the Mid MS Valley...
Thunderstorm development is anticipated during the afternoon along a
cold forecast to extend through southern WI and
eastern/southern IA. Thunderstorms along the front will initially be
displaced north of the better shear and buoyancy, so somewhat
transient updraft structures and/or frontal undercutting will likely
limit storm severity. Even so, high cloud bases and a deeply mixed
boundary layer could result in a few strong gusts. Later in the
evening, more storm development appears likely on the front as it
moves into eastern KS and northern/central MO. Here, stronger shear
and buoyancy should support more robust updrafts and a relatively
higher probability for severe storms. Large to very large hail is
the primary risk.
...Central Kansas into Oklahoma and northern Texas...
A dryline will extend from central KS south-southwestward into
northwest TX by mid afternoon as a surface low evolves near the TX
Panhandle/OK/KS border region. Strong diurnal heating will likely
erode most convective inhibition by the early evening, while steep
lapse rates contribute to moderate buoyancy along the dryline.
Isolated thunderstorms are possible on the dryline from central KS
into northwest TX during the 22-02 UTC period. Veering and
strengthening flow with height beneath 100-kt westerly 200-mb flow
will support supercells. Isolated large to very large hail will be
the primary risk with the stronger storms, although severe gusts are
also possible.
..Smith/Chalmers.. 05/04/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1241 PM CDT Mon May 04 2026
Valid 051200Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTERED OVER
ARKANSAS AND EXTENDING FROM NORTHEAST TEXAS INTO WESTERN
TENNESSEE...
...SUMMARY...
Scattered strong to severe storms are possible Tuesday afternoon and
evening from northeast Texas into western Tennessee, with the main
threat centered over Arkansas. Some storms may produce large hail,
damaging gusts or a couple tornadoes. Additional strong storms are
possible across parts of the Northeast.
...Synopsis...
A weakening upper low will move from Ontario into Quebec with a
leading speed max moving quickly out of the Great Lakes region.
Behind this system, high pressure will move southward into the
northern Rockies and Plains. The associated cold front will move
across the lower Great Lakes during the day, extending southwestward
across the Ozarks and into eastern OK where a surface low is
forecast.
Meanwhile, a positive-tilt upper trough will exist over the
southwestern states, with moderate to strong west/southwest flow
aloft expanding across the southern Plains to the Lower MS Valley.
Minimal height rises are forecast across this region, with the warm
advection regime aiding northward transport of low-level moisture
toward the Ozarks.
...Northeast TX into western TN...
A low pressure trough is forecast to develop generally from northern
TX into eastern OK and western AR during the afternoon, with the
main synoptic boundary slowing over northern AR. Models indicate
early day storms are likely over southeast MO, northeast AR and into
western KY and TN, dissipating by midday. This activity may
reinforce the effective frontal position into AR, where air mass
recovery will occur.
By late afternoon, scattered supercells are expected to form near
the surface trough from AR into northeast TX. Given robust moisture
with upper 60s F dewpoints, 60+ kt deep layer shear and effective
SRH maximized over AR, tornadoes will also be possible. The
combination of a capping inversion over much of the area, forced
cells timed with peak heating, and a potential downstream
outflow/enhanced zone of SRH, a strong tornado is conditionally
possible.
...NY into ME...
Strong heating ahead of the cold front and a plume of 50s F
dewpoints will lead to 500-1000 J/kg MUCAPE during the day, beneath
midlevel southwesterlies over 50 kt. Storms are forecast to develop
after 18Z from western into northern NY, with storms moving rapidly
northeastward across VT/NH and into ME. Forecast soundings indicate
40-50 kt deep-layer mean winds, which in combination with a mixed
boundary layer should support cells as well as bowing structures
capable of damaging gusts. The strongest cells may contain hail as
well. A brief tornado cannot be ruled out given 150-200+ m2/s2
effective SRH depicted across northern areas, though veering
low-level flow and/or deepening mixed layers may mitigate that
potential somewhat.
..Jewell.. 05/04/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1140 AM CDT Mon May 04 2026
Valid 041700Z - 051200Z
...Morning Update...
No changes were made to the Elevated risk area. Current satellite
imagery portrays high cloud cover overspreading much of the southern
Plains and portions of the northern Plains into the Upper Midwest.
Increasing cloud cover throughout the day is expected to deter
deeper mixing, maintaining marginal RH across the uppermost High
Plains. However, RH is still anticipated to remain elevated to near
critical this afternoon across portions of the TX Panhandle into
western OK where current surface observations depict 15-30 percent
values steadily decreasing.
Presently, a cold front is progressing across northern NE with
trailing northerly sustained winds of 20-25 mph and gusts up to 35
mph. Model soundings depict a dry sub-cloud layer and elevated
instability ahead of the approaching cold front, enhancing the
possibility for scattered showers and isolated thunderstorms across
southern NE, western KS and eastern CO. Recent rainfall, a slight
transition to green up, and expected precipitation overnight may
alleviate broader fire concerns should any ignitions occur. However,
areas where fuels remain dry, a west-northerly wind shift with
sustained 15-20 mph winds through the overnight hours could
temporarily exacerbate fire weather conditions before appreciable
rainfall arrives.
See the previous discussion for more information.
..Elizalde-Garcia.. 05/04/2026
.PREV DISCUSSION... /ISSUED 0136 AM CDT Mon May 04 2026/
...Synopsis...
A cut off low over the Southwest is expected to move eastward as it
merges with a strengthening subtropical jet stream south of a second
upper trough over the northern US and southern Canada. Enhanced
westerly flow aloft will move out of the southern Rockies and over
the Plains deepening a lee cyclone. This will promote dry and breezy
conditions over parts of the southern Plains with elevated
fire-weather conditions likely.
...Southern Plains...
Beneath the southern stream upper low, a lee cyclone will deepen
over the southern High Plains this afternoon. Trailing the low, a
developing dryline will serve as the eastern terminus of dry
westerly flow across parts of eastern NM and the TX/OK Panhandles.
Warm temperatures with westerly winds of 15-25 mph and 15-20 percent
RH will overlap a confined region of dry fuels across TX/OK. This
should support several hours of elevated to locally critical
fire-weather conditions. Some uncertainty remains on the exact
dryline positioning later this afternoon. Isolated convection is
also possible suggesting some precipitation may occur on the eastern
edge of the Elevated probabilities.
...Northern Plains/Midwest...
Gusty post-frontal winds are likely today across the northern Plains
and upper Midwest. However, cooler surface temperatures and cloud
cover will likely keep RH minimums above 35%. Still, some pockets of
drier air could support brief localized fire-weather concerns in
pockets of supportive fuels given stronger northwest wind gusts of
20-30 mph.
...Mid Atlantic...
Gusty southerly winds and a drier than normal air mass are likely to
develop this afternoon over parts of the Mid Atlantic and Piedmont.
A strengthening pressure gradient ahead of the deepening upper low
over southern Canada could support gusts of 10-15 mph. While RH will
be below 40%, area fuels remains rather limited owing to recent
precipitation. This should preclude broader fire-weather concerns,
though some localized risk remains possible.
...Please see www.spc.noaa.gov/fire for graphic product...
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