571
ACUS11 KWNS 132046
SWOMCD
SPC MCD 132046
CAZ000-132245-
MESOSCALE DISCUSSION 0096
NWS STORM PREDICTION CENTER NORMAN OK
0246 PM CST THU FEB 13 2025
AREAS AFFECTED...THE SACRAMENTO AND SAN JOAQUIN VALLEYS IN CENTRAL
CALIFORNIA
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 132046Z - 132245Z
PROBABILITY OF WATCH ISSUANCE...5 PERCENT
SUMMARY...SPORADIC THUNDERSTORMS ARE EXPECTED TO DEVELOP THROUGH THE
AFTERNOON HOURS WITHIN THE SACRAMENTO AND SAN JOAQUIN VALLEYS IN
CENTRAL CALIFORNIA. STRONGER/DEEPER STORMS WILL BE CAPABLE OF
ISOLATED SEVERE GUSTS, AND PERHAPS A TORNADO GIVEN SUFFICIENT
LOW-LEVEL WIND SHEAR.
DISCUSSION...ISOLATED DEEP CONVECTION HAS BEEN GRADUALLY DEVELOPING
WITHIN THE SOUTHERN SACRAMENTO/NORTHERN SAN JOAQUIN VALLEY OVER THE
PAST HOUR OR SO. THESE STORMS HAVE DEVELOPED WITHIN A SMALL POCKET
WHERE CLOUD BREAKS HAVE ALLOWED SURFACE TEMPERATURES TO WARM INTO
THE UPPER 50S AND LOW 60S, WHICH ARE REQUIRED TO SUPPORT DEEP,
SURFACE-BASED CONVECTION. OVERALL, POOR MID-LEVEL LAPSE RATES ARE
LIMITING (AND WILL CONTINUE TO LIMIT) BUOYANCY WITH MAXIMUM MUCAPE
VALUES OF AROUND 250-500 J/KG NOTED IN RECENT MESOANALYSIS
ESTIMATES. HOWEVER, STRONG DEEP-LAYER WIND SHEAR (EFFECTIVE BULK
SHEAR OF AROUND 40-45 KNOTS) IS IN PLACE ACROSS THE REGION AS A
MID-LEVEL JET ASSOCIATED WITH AN APPROACHING UPPER WAVE OVERSPREADS
THE REGION. ADDITIONALLY, BACKED LOW-LEVEL FLOW WITHIN THE VALLEY IS
SUPPORTING 0-1 KM SRH VALUES ON THE ORDER OF ABOUT 100 M2/S2. AS A
RESULT, ORGANIZATION OF DEEPER, LONGER LIVED CELLS APPEARS POSSIBLE
WITH AN ATTENDANT THREAT OF SEVERE WINDS AND PERHAPS A BRIEF TORNADO
(SMALL HAIL IS ALSO POSSIBLE, BUT THE LIMITED BUOYANCY AND DURATION
OF INDIVIDUAL CELLS CASTS UNCERTAINTY ON THE SEVERE HAIL POTENTIAL).
THIS THREAT WILL LIKELY BE CONFINED TO THE VALLEYS AND IS EXPECTED
TO BE TOO SPORADIC/ISOLATED TO WARRANT WATCH ISSUANCE.
..MOORE/THOMPSON.. 02/13/2025
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...HNX...STO...MTR...
LAT...LON 36402012 36322034 36302060 36462090 36762115 37322139
37972161 38772186 39132192 39352182 39442168 39542152
39542122 39392111 38672074 38092038 37612006 37321985
37021975 36751975 36511997 36402012
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