SPC MD 2339

[NorthGeorgiaWX]

MD 2339 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST AZ AND FAR SOUTHEAST CA

Mesoscale Discussion 2339
NWS Storm Prediction Center Norman OK
0231 PM CST Fri Dec 22 2023

Areas affected...Southwest AZ and far southeast CA

Concerning...Severe potential...Watch unlikely 

Valid 222031Z - 222230Z

Probability of Watch Issuance...5 percent

SUMMARY...Small to marginally severe hail will be possible in the
more robust storms this afternoon. Severe thunderstorm watch
issuance is not expected.

DISCUSSION...A trio of convective swaths persist downstream of a
slow-moving mid/upper low just offshore of the CA/Baja CA border.
The intermediate of these three swaths should largely impact the
lower portions of the CO/Gila Rivers over the next few hours near
the international border. Here, surface dew points from 54-58 F are
common, with progressively lower values farther north along the CO
River. Surface temperatures have largely struggled to warm beyond
the 50s east of southeast CA owing to the pervasive cloudiness, but
have popped into the low to mid 60s where cloud breaks have
occurred. Still, MLCAPE has struggled to exceed 500 J/kg. The
gradual eastward progression of the offshore low should yield
slightly cooler mid-level temperatures into early evening, fostering
a bit greater instability aloft. 

Although low-level shear is weak, VWP data from YUX highlights
favorable speed shear between 3-6 km. This will conditionally
support mid-level updraft rotation, especially in any cells that can
remain semi-discrete. This potential alignment with the modest
mid-level instability/buoyancy should support occasional hail growth
with magnitudes likely peaking from 0.75-1.25 inch.

..Grams/Hart.. 12/22/2023

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...TWC...PSR...

LAT...LON   32541495 32761532 33061534 33441513 33601466 33471355
            32981273 32651218 32201226 31831267 32541495 

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