ACUS01 KWNS 050549
SWODY1
SPC AC 050548

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1248 AM CDT Mon May 05 2025

Valid 051200Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR
SOUTHEAST NEW MEXICO INTO SOUTHWEST TEXAS...

...SUMMARY...
Severe thunderstorms are expected from the southern High Plains into
parts of central Texas this afternoon and evening. Scattered large
to very large hail and severe winds are the primary threats, though
a couple of tornadoes also are possible. Additional strong to severe
storms are possible along the eastern Florida coast and from eastern
North Carolina into the central Appalachians and upper Ohio River
Valley.

...Synopsis...
An omega blocking pattern continues to develop over the CONUS per
recent water-vapor imagery and 00 UTC upper-air analysis, with two
meandering upper lows over the Ohio River Valley and Southwest
respectively. Northward moisture advection and ascent on the eastern
periphery of both upper lows will promote another day of scattered
thunderstorms (including strong to severe storms) across the central
Appalachians/Mid-Atlantic and southern High Plains into the
Intermountain West.

...Southern High Plains...
Upper-level diffluence over the southern High Plains will continue
to promote gradual surface pressure falls and a southeasterly return
flow regime across far eastern NM and western TX through much of the
day. Although moisture return will initially be somewhat modest,
persistent broad-scale ascent over the region will result in cooling
temperatures aloft/steepening mid-level lapse rates that should
compensate for the poor moisture quality. Thunderstorm development
is expected initially within a warm advection regime across
south-central TX by early afternoon with additional storm
development by late afternoon across the Permian basin in closer
proximity to a deepening lee trough/sharpening dryline. Across both
regions, deep-layer wind shear on the order of 50 knots should
promote supercells with an attendant threat for large hail. Across
south-central TX, higher-quality moisture and stronger veering in
the lowest 1-2 km AGL may support a tornado threat.

By early evening, a shortwave trough embedded within the mean flow
(observable in water-vapor imagery off the southern CA coast as of
06 UTC) is forecast to overspread southwest TX. Stronger surface
pressure falls associated with this shortwave will induce
strengthening low-level winds, which will not only enlarge low-level
hodographs, but will augment moisture return into the region. Ascent
within the strengthening warm advection regime should result in
scattered supercell development between 00-06 UTC across the
southern Permian Basin and adjacent areas of southeast NM. Given the
increasingly favorable convective environment, a few long-lived
supercells appear possible and will be capable of producing large to
very large (2+ inch) hail and perhaps a couple of tornadoes. Upscale
growth into one or more clusters appears likely heading into the
overnight hours as lift spreads northeast into northwest and central
TX. There remains some uncertainty among guidance regarding the
development of a more organized MCS into TX through early Tuesday
morning, but cells developing within the warm advection regime ahead
of the upper wave may be capable of severe hail/wind.

...Central Appalachians and Mid-Atlantic...
Recent surface observations reveal a residual front/marine boundary
draped from eastern VA into the eastern Carolinas. East of this
boundary, richer low-level moisture in the form of low to mid-60s
dewpoints is noted extending northward into southeast PA. Aloft, an
embedded shortwave orbiting around the primary upper low is noted
over the mid-MS River Valley in recent water-vapor imagery. This
feature is expected to pivot into the Mid-Atlantic and central
Appalachians through the afternoon/evening and will be favorably
timed with the diurnal heating cycle. The combination of cold
temperatures aloft in proximity to the upper low and rich low-level
moisture will limit capping and promote thunderstorm initiation
along the boundary by early afternoon from the DelMarVa region into
NC. Further to the northwest, lift ahead of the embedded shortwave
combined with cold mid-level temperatures should promote
thunderstorm development across WV and OH by late afternoon. Across
both regions, 1000-1500 J/kg MLCAPE and elongated, nearly straight
hodographs should promote organized cells capable of large hail and
damaging winds. Similar thermodynamic and kinematic environments
were observed yesterday across the region, and yielded isolated to
scattered strong to severe thunderstorms, including a couple of
supercells.

...Eastern Florida Coast...
Regional 00 UTC soundings sampled somewhat steep mid-level lapse
rates atop a seasonally moist boundary layer (characterized by upper
60s to low 70s dewpoints) with limited inhibition. Heating of this
air mass should eliminate any residual capping by late morning and
early afternoon as temperatures climb into the 80s. Convective
initiation will become more probable by mid/late afternoon as
confluence along sea-breeze boundaries increases. Isolated to
scattered thunderstorms are expected, and 30-40 knot mid-level flow
should promote a few organized cells capable of producing large hail
and damaging gusts.

..Moore.. 05/05/2025

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