DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 280658
SWODY2
SPC AC 280657

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CST FRI FEB 28 2014

VALID 011200Z - 021200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A MID-LEVEL SHORTWAVE TROUGH EMBEDDED IN THE SRN COMPONENT OF A
MULTI-STREAM FLOW PATTERN COVERING THE CONUS WILL ADVANCE FROM THE
PACIFIC WATERS OFF THE SRN CA COAST TO THE SRN ROCKIES. IN
RESPONSE...A LLJ WILL STRENGTHEN OVER THE SRN PLAINS. THIS WILL
ENCOURAGE THE POLEWARD FLUX OF RICHER GULF MOISTURE CURRENTLY
RESIDING OVER THE SW GULF. AT THE SAME TIME...SHALLOW ARCTIC AIR
WILL SPREAD SWD TO THE E OF THE ROCKIES. THIS WILL OCCUR AS
CNTRL-PLAINS SFC RIDGING IS REINFORCED BENEATH UPPER-LEVEL
CONFLUENCE BETWEEN THE SHORTWAVE TROUGH AND DEEP...PHASING CYCLONIC
PERTURBATIONS OVER SRN CANADA. BY LATE SAT NIGHT...THE LEADING EDGE
OF THE ARCTIC AIR -- DELINEATED BY A STRONG COLD FRONT -- IS
FORECAST TO EXTEND FROM THE GREAT LAKES TO NRN TX.

...PORTIONS OF CENTRAL TEXAS NORTHEASTWARD TO SOUTHERN MISSOURI...
ISENTROPIC ASCENT ALONG A 30-40-KT LLJ WILL COMBINE WITH INCREASING
PW AND ELEVATED BUOYANCY TO POTENTIALLY SUPPORT THE DEVELOPMENT OF
ISOLATED THUNDERSTORMS SAT NIGHT. ALSO...FRONTAL ASCENT WILL
INTERCEPT RICHER RETURN MOISTURE ADVECTED INTO PARTS OF CNTRL/NRN TX
TO ENHANCE CONVECTIVE DEVELOPMENT IN THOSE AREAS LATE SAT NIGHT.

CONVECTION WOULD LIKELY BE ROOTED ATOP A STABLE NOCTURNAL BOUNDARY
LAYER AND/OR UNDERCUTTING BOUNDARY...WHILE STEEP MID-LEVEL LAPSE
RATES ACCOMPANYING AN OVERLYING EML PLUME CONTRIBUTE TO AROUND
500-1500 J/KG OF MUCAPE. AND...WITH MID-LEVEL WSWLY/S INCREASING TO
AROUND 50-60 KT IN ADVANCE OF THE SRN-STREAM SHORTWAVE TROUGH...DEEP
SHEAR WILL BE SUFFICIENTLY STRONG FOR A CONDITIONAL SVR-HAIL RISK.

HOWEVER...GIVEN THAT LOW-LEVEL ASCENT WILL INTERACT WITH ONLY THE
INITIAL STAGES OF RICHER MOISTURE RETURN...AND GIVEN THE LACK OF
STRONGER DEEP-LAYER ASCENT...SVR-STORM COVERAGE IS FORECAST TO BE
SUFFICIENTLY LIMITED TO PRECLUDE SLIGHT-RISK DESIGNATION.

...PORTIONS OF SOUTHEASTERN ARIZONA AND SOUTHWESTERN NEW MEXICO...
DCVA PRECEDING THE SRN-STREAM IMPULSE WILL COMBINE WITH MARGINAL
BUOYANCY EMBEDDED WITHIN A CORRIDOR OF MODESTLY ENHANCED PACIFIC
MOISTURE TO SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS DURING SAT
AFTERNOON/EVENING. STRONG DEEP-LAYER SWLY/S COULD SUPPORT A FEW
STRONG WIND GUSTS...AND AN ISOLATED SVR WIND GUST CANNOT BE RULED
OUT. HOWEVER...THE SVR POTENTIAL WILL BE LIMITED BY THE LACK OF
RICHER LOW-LEVEL MOISTURE AND ABUNDANT MID/HIGH-LEVEL CLOUDS
STUNTING DIURNAL HEATING/DESTABILIZATION.

...SOUTHERN CALIFORNIA...
COLD MID-LEVEL TEMPERATURES ACCOMPANYING THE SHORTWAVE TROUGH WILL
CONTRIBUTE TO CONVECTIVE BUOYANCY AND THE POTENTIAL FOR STORMS
THROUGH SAT EVENING. HOWEVER...WITH THE AXIS OF RICHER LOW-LEVEL
MOISTURE MOVING S OF THE REGION -- WELL REMOVED TO THE S OF A
FILLING SFC CYCLONE ADVANCING ONSHORE OVER THE CENTRAL CA COAST --
THE POTENTIAL FOR SVR STORMS WILL BE LIMITED.

..COHEN.. 02/28/2014

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