Day 1 Severe Weather Outlook

Valid 252000Z – 261200Z

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION
OF THE CENTRAL AND SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY
AS WELL AS SOUTHERN ARIZONA…

…SUMMARY…
Isolated strong wind gusts and hail remain possible this afternoon
into the evening from the Ozarks westward over parts of Oklahoma and
Kansas, as well as parts of Arizona and southeastern California.

…Discussion…

No changes have been made to this outlook. It still appears likely
that a few strong storms capable of gusty winds and some hail will
develop this afternoon and evening from the dryline/cold front
intersection in northwest OK, eastward along and north of the
southward-advancing cold front through northern OK, southern KS into
southern MO and northern AR. A few strong storms are also possible
over southern AZ into southeast CA.

..Dial.. 09/25/2019

.PREV DISCUSSION… /ISSUED 1056 AM CDT Wed Sep 25 2019/

…AZ/CA…
A cut-off upper low over northwest Mexico is expected to move slowly
northward into the Lower Colorado Valley later today. This area
should see strong heating this afternoon as temperatures climb into
the 80s and lower 90s. A pocket of cooler midlevel temperatures
will accompany the low, resulting in steepening lapse rates and
increasing CAPE this afternoon. 12z CAM solutions agree on the
development of scattered thunderstorms in this region, with hail and
gusty winds possible in the strongest cells. The main period of
risk will be between 20-04z.

…OK/KS/MO/AR…
Scattered pockets of remnant precipitation and mid clouds persist
today over this region, where dewpoints are in the 70s. Relatively
strong heating will occur this afternoon, yielding afternoon MLCAPE
values over 3000 J/kg. Strong instability and steep midlevel lapse
rates would support vigorous up/downdrafts in a few storms – with a
risk of hail and gusty winds. Forcing is weak and confidence in
significant coverage of thunderstorms before 00z is not particularly
high. However, the combination of isolated strong storms this
afternoon and more widespread convection after dark are sufficient
to maintain the ongoing MRGL risk with no changes.

$$

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