DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 131725
SWODY2
SPC AC 131723

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT MON MAY 13 2013

VALID 141200Z - 151200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
AN UPPER TROUGH WILL EJECT NEWD ALONG THE NERN ATLANTIC COAST...WITH
GENERALLY WEAK DEEP-LAYER FLOW ENCOMPASSING MUCH OF THE SRN
TWO-THIRDS OF THE CONUS. A BELT OF STRONG WLYS ALOFT WILL BE
CONFINED TO THE NRN TIER...WITH AN EMBEDDED LOW-AMPLITUDE SHORTWAVE
UPPER TROUGH MOVING ACROSS THE NRN PLAINS AND UPPER MIDWEST. AN
ASSOCIATED COLD FRONT WILL PROGRESS E-SEWD ACROSS THE UPPER MS
VALLEY AND NRN/CNTRL PLAINS. FARTHER S...AN INITIALLY CLOSED UPPER
LOW OVER NRN MEX WILL WEAKEN AND PROGRESS NEWD INTO THE SRN PLAINS
AND PHASE WITH THE SRN PERIPHERY OF WLY FLOW ALOFT.

...UPPER GREAT LAKES/UPPER MS VALLEY...
AN EML PLUME EMANATING OUT OF THE NRN ROCKIES WILL SPREAD EWD IN
CONJUNCTION WITH A SHORTWAVE UPPER TROUGH SKIRTING THE U.S./CANADIAN
BORDER. MODEST MOISTURE ADVECTION NWD WILL OCCUR WITHIN THE
WARM-SECTOR PRECEDING AN ASSOCIATED COLD FRONT...WHICH IS FORECAST
TO EXTEND FROM ERN MN SWWD INTO NWRN IA AND NERN NEB BY LATE
AFTERNOON. AS HAS BEEN FREQUENTLY BEEN THE CASE RECENTLY...LOW-LEVEL
MOISTURE FIELDS IN SUITE OF 12Z MODEL GUIDANCE APPEAR TO BE
SUBSTANTIALLY OVERDONE. MORE REALISTICALLY...SFC DEW POINTS IN THE
50S F AT BEST APPEAR LIKELY GIVEN A LACK OF A SUBSTANTIAL UPSTREAM
MOISTURE SOURCE ON LATEST SFC OBSERVATIONS. HOWEVER...WITH STRONG
HEATING FORECAST TO OCCUR WITH DAYTIME TEMPERATURES REACHING THE 90S
F...COMBINED WITH STEEP MIDLEVEL LAPSE RATES...THE ATMOSPHERE WILL
BECOME UNSTABLE WITH ESTIMATED MLCAPE VALUES OF 1000-1500 J/KG
DURING THE AFTERNOON.

ALTHOUGH THE COMBINATION OF INSTABILITY AND STRENGTHENING DEEP-LAYER
SHEAR WILL LEAD TO INCREASING SVR POTENTIAL ACROSS THE UPPER MS
VALLEY...THE RISK APPEARS HIGHLY CONDITIONAL GIVEN THE PRESENCE OF
CONVECTIVE INHIBITION...AND THE DISPLACEMENT OF THE STRONGEST
FORCING FOR ASCENT ACCOMPANYING THE SHORTWAVE WELL N OF THE MOST
UNSTABLE AIR. HOWEVER...IF ISOLATED HIGH-BASED THUNDERSTORMS CAN
DEVELOP ALONG THE COLD FRONT DURING THE AFTERNOON...AN ACCOMPANYING
THREAT FOR HAIL AND DMGG WIND GUSTS COULD EXIST. A RISK FOR HAIL MAY
ALSO ACCOMPANY ELEVATED CONVECTION N OF A WARM FRONT...DRAPED ACROSS
FAR NERN MN...NRN WI...AND SEWD INTO CNTRL MI...AND COULD EXTEND
INTO EARLY WED AS LOW-LEVEL WAA STRENGTHENS.

..ROGERS/BUNTING.. 05/13/2013

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.