Friday, February 18, 2011

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 181727
SWODY2
SPC AC 181726

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1126 AM CST FRI FEB 18 2011

VALID 191200Z - 201200Z

...NO SVR TSTM AREAS FORECAST...

...SRN AND CNTRL PLAINS...
AN UPPER-LEVEL RIDGE IN THE GREAT PLAINS TONIGHT WILL MOVE SLOWLY
EWD SATURDAY AS SOUTHWEST FLOW BECOMES ESTABLISHED OVER THE HIGH
PLAINS. IN RESPONSE...LOW-LEVEL FLOW WILL STRENGTHEN OVER THE SRN
AND CNTRL PLAINS AS MOISTURE RETURNS NWD INTO OK AND KS. ALTHOUGH
MODEL FORECASTS DEVELOP A POCKET OF MODERATE INSTABILITY ACROSS OK
SATURDAY AFTERNOON...FORECAST SOUNDINGS SHOW A STRONG CAP IN PLACE
WHICH WOULD PREVENT CONVECTIVE DEVELOPMENT DURING THE DAY. FURTHER
TO THE NORTH ACROSS KS AND NEB...THE CAP IS FORECAST TO BE WEAKER
AND LARGE-SCALE ASCENT SHOULD INCREASE SATURDAY EVENING AS THE EXIT
REGION OF A MID-LEVEL JET MOVES INTO THE CNTRL PLAINS. THIS SHOULD
RESULT IN SCATTERED THUNDERSTORM DEVELOPMENT SATURDAY EVENING ON THE
NOSE OF A WELL-DEFINED LOW-LEVEL JET WITH CONVECTIVE COVERAGE
INCREASING DURING THE OVERNIGHT PERIOD. CONFIDENCE IS RELATIVELY
STRONG THAT A LARGE CLUSTER OF ELEVATED THUNDERSTORMS WILL DEVELOP
IN THE CNTRL PLAINS SATURDAY NIGHT. THIS IS SUPPORTED BY MOST OF THE
MODELS INCLUDING THE GFS AND NAM. IN SPITE OF A COOL BOUNDARY
LAYER...NAM FORECAST SOUNDINGS SATURDAY NIGHT ACROSS NCNTRL KS SHOW
MUCAPE INCREASING TO THE 1500 TO 2000 J/KG RANGE. IN ADDITION TO THE
INSTABILITY...STRONG CLOUD LAYER SHEAR DUE TO THE APPROACHING
MID-LEVEL JET AND STEEP MID-LEVEL LAPSE RATES SHOULD BE SUPPORTIVE
OF AN ISOLATED HAIL THREAT. THIS THREAT FOR HAIL MAY PERSIST THROUGH
DAYBREAK SUNDAY AS LOW-LEVEL MOISTURE INCREASES FROM THE SOUTH AND
CONVECTION MOVES EWD INTO THE MID-MO VALLEY.

..BROYLES.. 02/18/2011

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

No comments: