DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 191644
SWODY2
SPC AC 191644

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1044 AM CST WED DEC 19 2012

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS MUCH OF THE SERN U.S....

...SERN U.S...

SRN EXTENT OF INTENSE HEIGHT FALLS CENTERED OVER THE OH VALLEY WILL
SPREAD ACROSS THE GULF COAST INTO THE CAROLINAS DURING THE OVERNIGHT
PERIOD. WHILE THE STRONGEST FORCING WILL BE CENTERED WELL NORTH OF
THE LOWER LATITUDINAL STATES A PROGRESSIVE COLD FRONT SHOULD
ENCOURAGE CONVECTIVE DEVELOPMENT AS IT ADVANCES FROM THE LOWER MS
VALLEY EARLY IN THE PERIOD INTO THE CAROLINAS AFTER DARK.

DESPITE THE STRONG SHEAR IN PLACE...OF PARTICULAR CONCERN THIS
PERIOD WILL BE THE LACK OF MEANINGFUL BUOYANCY ACROSS THE WARM
SECTOR. LATEST MODEL GUIDANCE SUGGEST PSEUDO ADIABATIC LAPSE RATES
WILL ENCOMPASS THE CURRENT SLGT RISK OUTLOOK AND CONVECTIVE
INTENSITY SHOULD BE MINIMIZED AND LIKELY SHALLOW IN NATURE. IN
FACT...FORECAST SOUNDINGS SUGGEST MANY UPDRAFTS SHOULD NOT ATTAIN
LEVELS SUFFICIENT FOR LIGHTNING DISCHARGE AS TOPS STRUGGLE TO REACH
7 KM WHERE TEMPERATURES WILL BE SIGNIFICANTLY WARMER THAN MINUS 20C.


DURING THE OVERNIGHT HOURS SOMEWHAT HIGHER MOISTURE MAY ADVANCE INTO
COASTAL CAROLINAS WHICH SHOULD LEAD TO A BIT MORE INSTABILITY ACROSS
THIS REGION. MODEL SOUNDINGS REFLECT THIS BUOYANCY WITH SBCAPE
APPROACHING 400 J/KG AFTER MIDNIGHT. GIVEN THE LLJ WILL STRENGTHEN
ACROSS THE MIDDLE ATLANTIC THE GREATEST RISK FOR TORNADIC SUPERCELLS
SHOULD BE ACROSS THIS REGION LATE.

WILL MAINTAIN 15 PERCENT SEVERE PROBS ACROSS THE SLGT RISK TO
ACCOUNT FOR STRONGLY SHEARED LOW TOPPED CONVECTION THAT COULD
PRODUCE DAMAGING WIND GUSTS...AND PERHAPS EVEN AN ISOLATED TORNADO.
HOWEVER...GIVEN THAT THE STRONGEST FORCING WILL BE LOCATED WELL
NORTH OF THE REGION IT APPEARS A VERY POOR LAPSE RATE/INSTABILITY
WARM SECTOR WILL IMPEDE POTENTIALLY MORE ROBUST DEVELOPMENT.

..DARROW.. 12/19/2012

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.