Day 1 Severe Weather Outlook

Valid 232000Z – 241200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
SOUTHERN KANSAS/NORTHEASTERN OKLAHOMA AND INTO SOUTHWESTERN
MISSOURI/NORTHWESTERN ARKANSAS…

…SUMMARY…
Storms capable of large hail are expected over parts of Kansas,
Oklahoma, southern Missouri, and Arkansas tonight along with a few
strong wind gusts.

…Discussion…
Aside from generally minor thunder line adjustments, the ongoing
forecast areas and reasoning appear to remain well-reflective of the
expected convective evolution this afternoon and tonight. The
primary changes this outlook will be to remove the thunder area over
the western PA/West Virginia area as convection has moved east of
the region and weakened, and to shrink the thunder area over the
coastal Pacific Northwest where appreciable lightning coverage looks
increasingly unlikely.

Otherwise, no substantive changes appear necessary at this time,
with a primarily elevated convective/potential severe event still
appearing likely to evolve in the Oklahoma/Kansas vicinity tonight.

..Goss.. 03/23/2020

.PREV DISCUSSION… /ISSUED 1120 AM CDT Mon Mar 23 2020/

…KS/OK/MO/AR tonight…
A midlevel shortwave trough over southern CA this morning will
progress eastward over AZ/NM by this evening, and will reach OK/KS
overnight. An associated lee cyclone will form by this evening in
southeast CO and likewise move eastward near the OK/KS border in
advance of the shortwave trough. Within the warm sector of the
developing lee cyclone, low-level moisture will spread northward
from TX toward OK during the day. However, the moistening will
occur beneath a relatively warm/capping layer between 850-700mb, and
stratus is likely to persist through the day and slow warming
beneath the cap.

There will be some threat for thunderstorm development rooted near
the surface this evening close to the CO/KS border, along the
surface trough/front north of the lee cyclone The more probable
scenario will be for elevated thunderstorm development 03-06z in the
zone of low-level warm advection and ascent within the left-exit
region of the midlevel jet from western into central KS. Steep
midlevel lapse rates and increasing low-level moisture will
contribute to MUCAPE near 1000 J/kg, which will support a threat for
large hail with the stronger storms overnight. Persistent capping
will likely limit the southern extent of storm development in OK,
though the elevated convection will expand eastward overnight across
KS toward northeast OK, southwest MO, AR and northern MS from
06-12z, with some continued threat for isolated large hail.

…AL/GA this afternoon…
A midlevel trough will continue eastward from the OH Valley to the
Mid-Atlantic by this evening. An associated segment of the
low-level jet will also develop eastward and away from the AL/GA
area, with low-level shear expected to weaken gradually through the
afternoon. Given that buoyancy and midlevel lapse rates will remain
rather modest, and forcing for ascent will be largely confined to
weak lift along the residual differential heating zone from
central/southern AL into GA, the threat for severe storms appears
too marginal to warrant an outlook area.

$$

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