SPC AC 101238
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0638 AM CST THU MAR 10 2011
VALID 101300Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF NC AND VA...
...NC/VA...
WATER VAPOR LOOPS SHOW A HIGHLY-AMPLIFIED UPPER TROUGH OVER THE
CENTRAL GULF COAST STATES. THIS FEATURE IS FORECAST TO ROTATE
NORTHEASTWARD TODAY ACROSS THE SOUTHEASTERN UNITED STATES AND MID
ATLANTIC REGION. THE PRIMARY SURFACE COLD FRONT ASSOCIATED WITH
THIS TROUGH EXTENDS FROM A LOW OVER SOUTHWEST VA INTO CENTRAL GA.
THE FRONT IS EXPECTED TO PROGRESS EASTWARD INTO THE CAROLINAS/VA BY
MID AFTERNOON WHERE SCATTERED THUNDERSTORMS ARE LIKELY TO FORM.
STRONG SOUTHERLY LOW LEVEL WINDS AHEAD OF THE FRONT WILL HELP TO
TRANSPORT MOISTURE NORTHWARD...WITH MID-UPPER 50S DEWPOINTS EXPECTED
FROM CENTRAL VA SOUTHWARD. FORECAST SOUNDINGS SHOW VERY MOIST
THERMODYNAMIC PROFILES WITH WEAK LAPSE RATES. THIS WILL TEND TO
LIMIT OVERALL UPDRAFT STRENGTH AND COVERAGE OF STRONG/SEVERE STORMS.
HOWEVER...THE STRENGTH OF THE LOW/MID LEVEL WIND FIELDS AND THE
PROGRESSIVE NATURE OF THE SYSTEM SUGGEST THE RISK OF AN ORGANIZED
LINE OF CONVECTION CAPABLE OF DAMAGING WINDS. VERTICAL SHEAR
PROFILES WILL ALSO BE FAVORABLE FOR ISOLATED TORNADOES. THE THREAT
SHOULD DIMINISH RAPIDLY BY LATE AFTERNOON AS THE STORMS APPROACH THE
COAST WHERE A COOLER/MORE STABLE AIR MASS WILL BE PRESENT.
...WESTERN WA...
A STRONG SHORTWAVE TROUGH WILL MOVE INLAND ACROSS WA TODAY...
SPREADING COLD MID LEVEL TEMPERATURES AND LARGE SCALE FORCING INTO
THE PACIFIC NORTHWEST REGION. SCATTERED SHOWERS AND A FEW
THUNDERSTORMS WILL BE POSSIBLE TODAY INTO TONIGHT AS FAR EAST AS
WESTERN ID. MODELS SHOW VERY STRONG LOW LEVEL WINDS AND 500MB
TEMPERATURES AOB -30C ALONG THE WA COAST THIS AFTERNOON AS THE
PRIMARY TROUGH AXIS MOVES ASHORE. ANY DEEP CONVECTION IN THIS
ENVIRONMENT WILL POSE A RISK OF ENHANCING AMBIENT WINDS TO SEVERE
LEVELS...AND/OR PRODUCING SMALL HAIL.
...SOUTH FL...
A FEW STRONG THUNDERSTORMS CANNOT BE RULED OUT THIS AFTERNOON AS THE
SURFACE COLD FRONT SAGS SOUTHWARD INTO SOUTH FL. AMPLE LOW LEVEL
MOISTURE AND DAYTIME HEATING MAY PROVIDE SUFFICIENT INSTABILITY FOR
HAIL IN THE STRONGEST CORES...DESPITE RATHER WEAK SHEAR PROFILES AND
DECREASING UPPER FORCING WITH TIME.
..HART/COHEN.. 03/10/2011
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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