ACUS01 KWNS 140550
SWODY1
SPC AC 140549

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1249 AM CDT Wed May 14 2025

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
NEBRASKA...THE EASTERN DAKOTAS...FAR NORTHWEST IOWA...AND FAR
SOUTHWEST MINNESOTA...

...SUMMARY...
Scattered strong to severe thunderstorms are possible mainly over
parts of the Dakotas and Nebraska Wednesday afternoon and evening,
and perhaps into far western Iowa and southwest Minnesota overnight.
A few strong to severe storms may occur from parts of the southern
Appalachians to the Carolinas and Mid-Atlantic Wednesday afternoon.

...Synopsis...
A broad mid-level jet will eject into the central Plains on
Wednesday with a deepening surface low moving north through the
central Plains and into the northern Plains. Farther east, a
mid-level shortwave trough will advance east from the southern
Appalachians to the western Atlantic by the end of the period.

...Northern/Central Plains...
Low-level moisture is in place across the Plains this morning with
upper 50/low 60s dewpoints in Kansas and mid 60s dewpoints across
Oklahoma. However, this moisture is very shallow with a mean mixing
ratio around 11 g/kg from the OUN, LMN, and FWD 00Z RAOBs.
Therefore, expect this moisture to advect northward through the day
given the strengthening southerly flow associated with the deepening
cyclone. However, dewpoints across Nebraska and into the Dakotas
will likely remain in the upper 50s to low 60s given the upstream
moisture quality. Nonetheless, this will be sufficient for MLCAPE
around 2000-3000 J/kg near the NE/KS border with weaker instability
farther north.

Expect storm development in the vicinity of the surface low
Wednesday afternoon where surface convergence will be maximized.
Storms may quickly develop along the frontal zone from north-central
Nebraska and into the Dakotas. These storms will pose a threat for
large hail and damaging wind gusts. Farther south, additional
development is possible along the dryline/triple point across
southwest Nebraska. These storms may have the best potential to be
discrete longer and should be supercellular given 30 to 35 knots of
shear in the region. This will also be the region with the greatest
2+ inch hail potential given the strong instability, moderate shear,
and steep lapse rates.

Low-level shear will increase after 00Z as the low-level jet
strengthens. However, by this time, expect inhibition to increase
substantially across the central Plains with storm mode becoming
more linear across northern Nebraska and into eastern South Dakota
which should limit the overall tornado threat.

...Southern Appalachians into the Carolinas and the Mid-Atlantic...
Weak to moderate instability will develop from the southern
Appalachians to the Carolinas on Wednesday. As a mid-level shortwave
trough overspreads the region, expect scattered thunderstorm
development. 25 to 30 knots of shear will support some storm
organization including potential for transient supercell structures.
In addition, modestly steep mid-level lapse rates are apparent. This
should support the potential for large hail and perhaps isolated
damaging wind gusts. Hail is expected to be the primary threat
across the region, but coverage is not expected to be high enough to
support a Slight (Level 2 out of 5) risk.

..Bentley.. 05/14/2025

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