MESO: Mesoscale Discussion 1296

ACUS11 KWNS 272219
SWOMCD
SPC MCD 272219
AZZ000-272345-

MESOSCALE DISCUSSION 1296
NWS STORM PREDICTION CENTER NORMAN OK
0519 PM CDT WED JUN 27 2012

AREAS AFFECTED...SERN AZ

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 272219Z - 272345Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...THUNDERSTORMS MAY POSE AN ISOLATED THREAT FOR STRONG WIND
GUSTS INTO THE EARLY EVENING...AND A WW WILL NOT BE NEEDED.

DISCUSSION...ISOLATED CONVECTION PERSISTS WITHIN A PLUME OF
1.00-1.25 INCH PW VALUES PER GPS PW DATA WHERE MODEST BOUNDARY-LAYER
MOISTURE -- CHARACTERIZED BY SFC DEWPOINTS IN THE MIDDLE 40S TO
AROUND 50F -- IS YIELDING MLCAPE VALUES AROUND 500 J/KG. WEAK
TROPOSPHERIC FLOW PER TUSCON VWP DATA WILL SUPPORT A PRIMARILY PULSE
CONVECTIVE MODE...WITH OUTFLOW BOUNDARIES SURGING WNWWD TO NNWWD
OWING TO AOB 20 KT OF ESELY TO SSELY FLOW BELOW 3 KFT AGL.
ADDITIONAL CONVECTIVE DEVELOPMENT ALONG THESE BOUNDARIES WILL
PROMOTE PROPAGATION INTO AREAS WHERE OVERTURNING HAS NOT STABILIZED
THE BOUNDARY LAYER...PERHAPS INCLUDING THE TUCSON AREA DURING THE
NEXT HOUR OR TWO. DEEP/WELL-MIXED SUB-CLOUD LAYERS IN ASSOCIATION
WITH SFC TEMPS FROM THE UPPER 90S TO AROUND 105 DEGREES WILL PROMOTE
A THREAT FOR LOCALLY STRONG WIND GUSTS...POTENTIALLY NEARING
MARGINALLY SVR LEVELS ON A VERY ISOLATED BASIS...WITH DCAPE VALUES
IN EXCESS OF 1500 J/KG. STORMS WILL WEAKEN BY MID-EVENING WITH
NOCTURNAL COOLING/STABILIZATION.

..COHEN/HART.. 06/27/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON 31301095 31391136 31801184 32831164 33481126 33921072
33940999 33750954 33290927 32370914 31570935 31290993
31301095

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