726
ACUS01 KWNS 030603
SWODY1
SPC AC 030601

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Sun Aug 03 2025

Valid 031200Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN HIGH PLAINS...

...SUMMARY...
Large to very large hail and damaging winds will be possible this
afternoon and evening over parts of the central/southern High
Plains. Additional strong to severe storms are probable in the
Northwest during the afternoon.

...Central High Plains...
Low-level upslope flow overspread by continued northwesterly flow
aloft will support scattered storm development across the central
High Plains by early afternoon. Near a weak surface low/lee trough,
storms moving east off the higher terrain across WY and SD, will
gradually encounter dewpoints in the upper 50s to low 60s F. This
will allow for moderate instability and intensification of storms as
they move into the deeper moisture, though shear will be weaker to
the east. Steep low/mid-level lapse rates could support isolated
damaging gusts and occasional hail with the strongest storms as
semi-organized cluster gradually evolve.

...Parts of the Southern Plains...
Any early morning MCS/cluster of storms is likely to be ongoing at
the start of the period from western OK into the eastern TX
Panhandle. This feature casts significant uncertainty on the
convective evolution throughout the day across parts of TX, KS and
OK. While these initial storms should slowly weaken through the
morning, a convectively enhanced shortwave trough, embedded within
the northwesterly flow aloft, will continue southeastward
overspreading the prior cold pool. Lift from the upper trough, in
combination with strong heating and low-level moist advection, could
support storm regeneration over parts of central OK and north TX by
early afternoon. A conditional risk for supercells capable of hail
and damaging winds is possible given moderate instability and 35-40
kt of deep-layer shear.

Across the southern High Plains, the trailing outflow from the
morning convective complex should gradually modify over parts of
southeastern CO and the TX/OK Panhandles. The left exit region of a
90+ kt upper-level jet will overspread the lee trough and modifying
outflow around peak heating. This should support isolated supercell
development across southeastern CO into the TX/OK Panhandles. The
parameter space for large to very large hail will be quite favorable
owing to elongated hodographs with deep-layer shear of 40-50 kt
overlapping with MLCAPE of 2500-3500 J/kg, and mid-level lapse rates
of 8-9 C/km. Backed low-level flow and stronger shear near the
outflow boundary could also support a tornado or two given the
expected supercell storm mode.

With time, some upscale growth into a linear cluster or MCS is
possible into the TX South Plains and western Red River Valley
tonight. While uncertainty on the storm coverage remains given the
overall modest forcing for ascent, this scenario, supported by
several CAM solutions, seems reasonable. Should this occur, an
increased risk for damaging gusts could accompany a linear cluster
overnight into portions of west TX.

...Northwest...
Modest surface moisture beneath a fairly pronounced shortwave trough
over the eastern Pacific will move inland today supporting scatted
to numerous thunderstorms across portions of the Northwest. A belt
of stronger mid-level flow ahead of the trough will help to increase
deep-layer shear to 30-40 kt, supporting some storm organization
despite limited instability (SBCAPE generally less than 1000 J/kg).
Steep lapse rates with inverted-v thermodynamic profiles and the
potential for high-based semi-organized clusters will favor strong
downdrafts capable of occasional severe gusts with the stronger
storms. Small hail will also be possible with any more persistent
clusters or weak supercell structures despite the limited buoyancy.

..Lyons.. 08/03/2025

$$