SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1239 AM CDT Fri May 02 2025
Valid 021200Z - 031200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TODAY INTO THIS
EVENING ACROSS PARTS OF CNTRL/ERN KY...MIDDLE AND ERN TN...NWRN
GA...NRN AL...NRN AND CNTRL MS...SERN AR...NRN AND CNTRL LA...CNTRL
AND ERN TX...
...SUMMARY...
Widespread strong thunderstorm development, potentially including
several organizing clusters, appears likely in a corridor across
parts of central and eastern Texas, through the lower Mississippi
and Tennessee Valleys, into the Cumberland Plateau by this evening.
These may be accompanied by a risk for large hail, initially, before
widespread strong to severe gusts becomes more common.
...Discussion...
Although a mid/upper high may be attempting to form east of the
Cascades, within large-scale riding shifting inland of the Pacific
coast, models suggest that this will be short-lived. And it appears
that the ridging will slowly continue eastward across the
Intermountain West and Rockies through this period, as one upstream
short wave trough pivots northward across British Columbia, and
another digs toward the northern Pacific coast. Downstream, a
significant short wave trough, currently digging to the lee of the
northern Rockies, is forecast to continue across the central Great
Plains through lower Missouri Valley and Ozark Plateau vicinity by
12Z Saturday.
It still appears that the trough over the Great Plains will be
preceded by a convectively augmented short wave perturbation, just
now beginning to evolve across the Texas Panhandle into Red River
vicinity, and forecast to accelerate north-northeastward through the
Ohio Valley later today and tonight. Trailing this feature, a
front, probably reinforced by considerable outflow from overnight
convection, is forecast to advance south/southeast of the Red River
and Ozark Plateau vicinity by 12Z this morning. Ahead of this
front, models indicate that a seasonably moist boundary layer will
become characterized by sizable CAPE, with insolation beneath
initially steep mid-level lapse rates, across much of central and
southern Texas through the lower Mississippi Valley. By late
afternoon, low-level moisture advection may contribute to similar
destabilization in a corridor across the Tennessee Valley into the
western slopes of the Appalachians.
...Southern Great Plains into western slopes of Appalachians...
While it is possible that one more prominent surface frontal wave
may eventually form across parts of the Mid South into lower Ohio
Valley late today into tonight, it appears that this may remain
relatively weak, and the surface front may tend to advance south of
the stronger mid-level westerlies. However, models indicate that
the environment within the developing instability axis will become
at least modestly sheared, as broadly difluent mid/upper flow
downstream of the digging trough supports increasing and
intensifying thunderstorm development by midday.
This may include re-intensification of overnight storms across the
Mid South into Ohio Valley, and the initiation of additional storms
southwestward across central Texas. There is a considerable signal
in model output that convection will become widespread, with
potential for the evolution of at least a couple of notable
organizing storm clusters.
Initial thunderstorm development may be accompanied by the risk for
large hail, particularly across central Texas, but perhaps also
across and northeast of the lower Mississippi Valley. Thereafter,
precipitation loading, evaporative cooling and melting may
contribute to strong downbursts, before convectively generated
surface cold pools consolidate and strengthen, accompanied by
increasingly widespread strong to severe gusts as convection spreads
eastward and southeastward into this evening.
..Kerr/Moore.. 05/02/2025
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