DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 281724
SWODY2
SPC AC 281722

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1122 AM CST THU FEB 28 2013

VALID 011200Z - 021200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MODELS SUGGEST THAT UPPER RIDGING WILL BEGIN TO BUILD NORTHWARD FROM
THE SUBTROPICAL EASTERN PACIFIC...TOWARD CALIFORNIA...LATER TODAY
AND TONIGHT. THIS APPEARS LIKELY TO OCCUR IN PHASE WITH AMPLIFIED
LARGE-SCALE MID-LATITUDE RIDGING...WHICH IS EXPECTED TO CONTINUE
DEVELOPING INLAND ACROSS MUCH OF THE PACIFIC COAST STATES ...AND
THROUGH MUCH OF THE INTERMOUNTAIN WEST AND ROCKIES BY 12Z SATURDAY.
AS THIS OCCURS...UPPER TROUGHING DOWNSTREAM IS EXPECTED TO GRADUALLY
CONSOLIDATE AND SHARPEN IN POSITIVELY TILTED FASHION EAST OF THE
ROCKIES...SUPPORTING GENERALLY COOL AND DRY SURFACE RIDGING ACROSS
THE PLAINS/MISSISSIPPI VALLEY...SOUTHWARD THROUGH MUCH OF THE GULF
OF MEXICO. AT THE SAME TIME...CYCLONIC OFFSHORE LOW-LEVEL FLOW
PROBABLY WILL LINGER ACROSS MUCH OF THE ATLANTIC SEABOARD. AS A
RESULT OF THIS EVOLVING PATTERN...GENERALLY STABLE CONDITIONS APPEAR
LIKELY TO PERSIST ACROSS MUCH OF THE NATION WITH LOW TO NEGLIGIBLE
CONVECTIVE POTENTIAL.

...TEXAS...
MODELS DO INDICATE THAT A -30C 500 MB COLD CORE WILL DEVELOP
SOUTHWARD ACROSS THE SOUTHERN PLAINS DURING THE DAY FRIDAY...WITH AT
LEAST A COUPLE OF SIGNIFICANT SHORT WAVE IMPULSES DIGGING WITHIN
NORTHWESTERLY MID/UPPER FLOW. BENEATH THE SOUTHERN PERIPHERY OF
THIS REGIME...THE EAST SOUTHEASTWARD ADVECTION OF ELEVATED MIXED
LAYER AIR...AND SURFACE HEATING LIKELY WILL CONTRIBUTE TO VERY STEEP
LOWER/MID TROPOSPHERIC LAPSE RATES ACROSS THE EDWARDS PLATEAU INTO
THE HILL COUNTRY. AND MODELS SUGGEST THAT THIS WILL OCCUR IN
ADVANCE OF A STRENGTHENING UPWARD VERTICAL MOTION FIELD FORECAST TO
OVERSPREAD THE REGION DURING THE PEAK AFTERNOON HEATING. DESPITE
THE VERY LIMITED MOISTURE...FORCING AND INSTABILITY MAY BECOME
SUFFICIENT TO SUPPORT A CONSOLIDATING LOW-TOPPED...BUT RELATIVELY
HIGH-BASED...CLUSTER OF CONVECTION. WHILE PRECIPITATION PROBABLY
WILL BE MEAGER...VARIOUS MEMBERS OF THE NCEP SREF DO SUGGEST ENOUGH
CAPE EXTENDING THROUGH THE FAVORABLE MIXED PHASE LAYER FOR CHARGE
SEPARATION...AND THE PRODUCTION OF LIGHTNING...SUPPORTING AT LEAST
MINIMUM THRESHOLD /10 PERCENT/ PROBABILITIES FOR THUNDERSTORMS
FRIDAY AFTERNOON.

..KERR.. 02/28/2013

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