SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Sun May 04 2025
Valid 041200Z - 051200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR EAST-CENTRAL
INTO SOUTHEAST NM AND A SMALL PART OF ADJACENT WEST TX...
...SUMMARY...
Strong to potentially severe storms are forecast across east-central
and southeast New Mexico this afternoon and evening, with a threat
for large hail, isolated severe gusts, and possibly a tornado. Other
strong to locally severe storms are possible from Florida northward
into the Mid Atlantic and Allegheny Plateau.
...Synopsis...
An amplified upper-level pattern will remain in place today across
the CONUS. A deep trough will cover much of the West, as an embedded
mid/upper-level cyclone moves slowly eastward across the Southwest.
Farther east, a deep mid/upper-level cyclone is forecast to remain
nearly stationary over parts of the OH/TN Valleys.
At the surface, a cold front will continue moving across parts of
the Southeast, while the Mid-Atlantic portion of the front is
expected to move little through the day. A weak surface low will may
persist across OH/WV/southwest PA, with other weak waves potentially
developing along the front. Farther west, lee troughing will result
in strengthening southeasterly low-level flow into parts of NM and
west TX, accompanied by modest moisture return.
...NM into west TX...
While low-level moisture will remain rather limited, dewpoints
increasing through the 40s to near 50 F beneath steep midlevel lapse
rates will result in MLCAPE of 500-1000 J/kg by late afternoon into
the evening. Large-scale ascent downstream of the midlevel cyclone
over the Southwest will aid in development of scattered to numerous
thunderstorms from northern into east-central NM, with more isolated
storms possible into far southeast NM and west TX. Veering wind
profiles and increasing midlevel flow will provide sufficient
deep-layer shear for storm organization, and development of a few
supercells will be possible. Large hail and localized severe gusts
will be possible. In addition, enlarging low-level hodographs and
gradually improving moisture could support a tornado or two if any
mature supercells can persist through late afternoon into the
evening.
...Florida...
A few stronger storms will be possible across parts of north FL
during the morning, in the vicinity of the cold front. Depending on
the evolution of any morning convection and related cloudiness,
relatively cold temperatures aloft and diurnal heating will allow
for moderate destabilization during the afternoon. Scattered diurnal
storm development is expected, especially in the vicinity of the
Atlantic sea breeze. MLCAPE of around 2000 J/kg and effective shear
of 25-30 kt will support potentially organized storms capable of
hail and damaging gusts. Some tornado threat could also materialize
in the vicinity of the sea breeze or any other boundaries.
Some uncertainty remains regarding how any morning convection and
its possible persistence will affect sea-breeze-related storm
development, especially with northward extent up the coast.
...Allegheny Plateau into the Carolinas...
Cold temperatures aloft may support modest diurnal destabilization
across parts of OH/WV/western PA. Storm development may be aided
during the afternoon by one or more low-amplitude vorticity maxima
rotating around the midlevel cyclone. Low-level flow is expected to
remain rather weak, but modestly veering wind profiles and moderate
midlevel flow could support some storm organization, if sufficient
buoyancy can be realized. Hail and locally gusty winds could
accompany the strongest storms. A mesoscale corridor of somewhat
greater threat could evolve, depending on the magnitude of
heating/destabilization.
Farther south into the Carolinas and parts of the Mid Atlantic,
somewhat stronger diurnal heating is expected, and MLCAPE may
increase to near/above 1000 J/kg. However, storm coverage is more
uncertain, with a notable midlevel dry slot and only weak to modest
large-scale ascent expected with southward extent. Any storms that
can mature within this environment could become modestly organized
with a threat of isolated hail and damaging gusts.
...Eastern ID into southwest MT...
Scattered storm development is possible this afternoon and evening
from eastern ID into southwest MT, within an environment
characterized by cold temperatures aloft and steep lapse rates.
Deep-layer shear will be relatively modest, but a couple stronger
storms with small hail and gusty winds will be possible. If trends
end up supporting the more aggressive guidance regarding
destabilization in this area, then severe probabilities may
eventually be needed.
..Dean/Moore.. 05/04/2025
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