ACUS01 KWNS 031954
SWODY1
SPC AC 031952

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0252 PM CDT Sat May 03 2025

Valid 032000Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CAROLINAS INTO THE MID-ATLANTIC AND NEW ENGLAND...

...SUMMARY...
Scattered strong to severe thunderstorms are possible this afternoon
and evening from parts of the Carolinas into the Mid-Atlantic and
Northeast. A more isolated severe threat may develop across the
Southeast, and also across parts of the Great Basin and far west Texas.

...20z update...
Minimal changes were made to the current forecast, mostly trimming
probabilities from the west. A broad corridor of severe potential
continues from southern New England to the Gulf Coast. Partial
diurnal heating east of the frontal zone is supporting a few
clusters of stronger storms from southern NY/New England and the Mid
Atlantic to the western Carolinas. 30-40 kt of bulk shear, in
combination with 500-1000 J/kg of MLCAPE will favor damaging winds
as the main threat with the multicell clusters or transient
supercells that develop as they spread northeastward through the
evening. Some sporadic hail and a brief tornado will also be
possible with any stronger rotating storms.

...AL and western GA...
Another corridor of locally stronger clusters may evolve across the
Gulf Coast, to central AL and into western GA later this afternoon
into the evening. Here, stronger diurnal heating (temps in the mid
to upper 70s F) amid enhanced mid-level flow from the sub tropical
jet may pose a locally greater severe risk for a few hours. A mix of
line segments and some supercell structures could pose a locally
greater severe risk. Some consideration was given to higher wind
probabilities here, but confidence in more robust convective
organization remains low, with lingering cloud cover, modest forcing
and limited buoyancy. Otherwise, the outlook remains unchanged, see
the previous discussion for more info.

..Lyons.. 05/03/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Sat May 03 2025/

...Carolinas into the Mid-Atlantic and New England...
Generally upper 50s to low 60s surface dewpoints are present
along/east of the higher terrain of the Blue Ridge/Appalachians from
parts of the Carolinas northeastward into the Mid-Atlantic and
southern New England. Even with mid-level lapse rates remaining
fairly modest, around 500-1000 J/kg of MLCAPE is forecast to develop
this afternoon in a narrow corridor across these regions with
additional filtered daytime heating. Large-scale ascent associated
with a slow-moving upper trough over the mid MS Valley will
gradually overspread the destabilizing warm sector in the next few
hours. This ascent, along with orographic lift over the higher
terrain, should aid in the development of scattered strong to severe
thunderstorms this afternoon and evening.

Around 30-40 kt of deep-layer shear should be present, which will
support a mix of multicells and marginal supercells. Scattered
damaging winds should be the main threat with the multiple clusters
that develop as they spread northeastward through the evening, but
some hail may also occur with any sustained supercell. Greater
confidence exists in overall thunderstorm coverage and intensity
across parts of the Mid-Atlantic into southern New England, where
the Slight Risk has been maintained with minimal changes. The
tornado threat remains less clear across these regions, but some
modest enhancement to the southwesterly low-level flow could aid in
occasional low-level updraft rotation.

...Southeast...
12Z soundings across the central Gulf Coast states show that
convection that occurred yesterday into the overnight/early morning
hours generally stabilized the environment this morning. Widespread
cloudiness evident in visible satellite imagery late this morning
should tend to delay/hinder robust destabilization this afternoon
along/ahead of the southeastward-advancing synoptic cold front,
which lends considerable uncertainty to the overall intensity of
renewed convection along/ahead of the front later today. Still,
mid-level winds and related deep-layer shear are forecast to
gradually strengthen through the afternoon/evening as the upper
trough over the mid MS/lower OH Valley develops slowly eastward.
This should support some threat for organized convection, and
isolated damaging winds may occur with any clusters that can form.
With continued concerns regarding the degree of instability
developing this afternoon, confidence remains too low to include
greater severe wind probabilities at this time.

...Great Basin...
Modestly enhanced southerly mid-level flow will overspread parts of
the western and northern Great Basin as an upper trough moves
eastward over the western CONUS through the afternoon/evening. While
boundary-layer moisture is expected to remain very limited,
increasing mid-level moisture and diurnal destabilization should aid
in weak MLCAPE developing by this afternoon. Scattered thunderstorms
are forecast to develop and spread northward, with an isolated
threat for severe winds given steepened low-level lapse rates and a
very well mixed boundary layer. Small hail may also occur with the
strongest cores.

...Far West Texas...
Even though large-scale ascent should remain weak/nebulous across
far west TX and vicinity today, isolated supercell development still
appears possible in a modest post-frontal/low-level upslope flow
regime. Both low-level winds and MLCAPE are expected to remain
modest, but strengthening westerly winds with height in mid/upper
levels should support around 30-40 kt of deep-layer shear and some
updraft organization. Based on latest guidance trends showing a
supercell or two developing this afternoon/evening, have introduced
a Marginal Risk for hail across parts of far west TX and vicinity.

$$
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