231
ACUS01 KWNS 010601
SWODY1
SPC AC 010600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Wed May 01 2024

Valid 011200Z - 021200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WEST AND CENTRAL TEXAS NORTHWARD INTO WESTERN OKLAHOMA...THE EASTERN
TEXAS PANHANDLE AND SOUTH-CENTRAL KANSAS...

...SUMMARY...
Severe storms with large hail up to 3 inches in diameter, wind
damage, and a few tornadoes will be possible this afternoon and
evening across parts of the southern and central Plains. The
greatest severe threat is expected from north-central Kansas
southward across western Oklahoma, the eastern Texas Panhandle into
northwest and west-central Texas.

...Southern and Central Plains...
An upper-level trough will move across the Intermountain West and
Desert Southwest today, as mid-level flow remains southwesterly
across the southern and central Plains. At the surface, a low is
forecast to deepen across southeast Colorado, with a warm front
moving northward across central and north-central Kansas. A dryline
will be located from southwest Kansas southward into west Texas. A
moist airmass, with surface dewpoints in the mid to upper 60s F,
will be located from the dryline eastward across much of the
southern Plains. As surface heating takes place during the day,
isolated convective initiation is expected across the moist airmass.
More vigorous convective development will develop during the mid to
late afternoon from the vicinity of the warm front in central
Kansas, southward along the dryline into the southern Plains.

Current model runs suggest that the storms will develop in the
eastern Texas Panhandle and move into western Oklahoma. These storms
are forecast to remain semi-discrete. RAP forecast soundings in
western Oklahoma at 00Z/Thursday have MLCAPE of 3000 to 4000 J/kg,
with 0-6 km shear in the 25 to 30 knot range, and 700-500 mb lapse
rates near 8 C/km. This should support storms with some supercell
structure, and a potential for large to very large hail up to 3
inches in diameter. 0-3 km storm-relative helicity is forecast to be
in the 200 to 250 m2/s2 range to the east of the dryline from
southwest Kansas into northwest Texas, suggesting tornadoes will be
possible.

Further north into central and north-central Kansas, model forecasts
suggest that initiation will remain isolated due to a lack of
large-scale ascent. By 00Z/Thursday, RAP forecast soundings near
Salina have 0-6 km shear around 50 knots, with 0-3 km storm-relative
helicity in the 300 to 400 m2/s2 range. This would be favorable for
a tornado threat, if cells can initiate along the warm front. The
current thinking is that the models may be underdone with convection
along the warm front. If convergence is strong enough, a discrete
supercell could initiate during the late afternoon or early evening.
The strengthening low-level jet would make low-level shear favorable
for a tornado or two in central or north-central Kansas. Large to
very large hail would also be possible with any cell that can
develop on the warm front. These threats appear conditional.

Further south across northwest and west-central Texas, a linear MCS
is expected to develop. MLCAPE to the east of the dryline is
forecast to be in the 3000 to 4000 J/kg range, with 700-500 mb lapse
rates near 8 C/km. This, combined with 0-6 km shear in the 25 to 30
knot range may support storm rotation early in the event. Cells that
rotate can be expected to have large to very large hail. However, a
rather quick transition to linear mode is forecast in the late
afternoon. This linear MCS may be associated with severe wind gusts
along the leading edge. The isolated wind-damage threat should
affect areas in central Texas by mid to late evening.

..Broyles/Thornton.. 05/01/2024

$$