Friday, June 1, 2012

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 011221
SWODY1
SPC AC 011219

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0719 AM CDT FRI JUN 01 2012

VALID 011300Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE
CAROLINAS...MID ATLANTIC STATES...INTO PA/NY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL HIGH
PLAINS...

...CAROLINAS/MID ATLANTIC INTO NY/PA...
MORNING WATER VAPOR LOOPS SHOW A LARGE UPPER TROUGH MOVING ACROSS
THE MID MS VALLEY. THIS TROUGH WILL ROTATE EASTWARD INTO THE
CENTRAL APPALACHIANS BY LATE AFTERNOON...WHILE THE ASSOCIATED COLD
FRONT CROSSES THE MOUNTAINS AND INTO THE MID ATLANTIC REGION.
RELATIVELY STRONG SOUTHERLY LOW LEVEL WINDS AHEAD OF THE FRONT WILL
HELP TO TRANSPORT INCREASINGLY RICH MOISTURE NORTHWARD INTO PARTS OF
VA/MD/PA AND RESULT IN POCKETS OF MODERATE AFTERNOON CAPE. DEEP
LAYER SHEAR WILL BE SUFFICIENT FOR SUPERCELL STORM STRUCTURES AND
BOWING LINE SEGMENTS...WHILE LOW LEVEL SHEAR ALSO PROMOTES A RISK OF
A FEW TORNADOES THIS AFTERNOON AND EVENING.

OVERALL...ONGOING FORECAST APPEARS ON TRACK WITH VERY FEW CHANGES
MADE. STORMS MAY INTENSIFY BY EARLY AFTERNOON ALONG THE COLD FRONT
OVER WESTERN PA INTO CENTRAL WV...BUT THE PRIMARY SEVERE THREAT WILL
BE MID-LATE AFTERNOON AS PRE-FRONTAL STORMS FORM OVER CENTRAL VA AND
SPREAD NORTHEASTWARD INTO MD. WHILE IT DOES APPEAR THAT AN ACTIVE
SEVERE WEATHER DAY IS ON TAP FROM NC NORTHWARD INTO PARTS OF
PA...SEVERAL MITIGATING FACTORS CONTINUE TO WARRANT MAINTENANCE OF
SLIGHT RISK OUTLOOK. EARLY MORNING VISIBLE IMAGERY SHOWS WIDESPREAD
CLOUDS AND SCATTERED SHOWERS ACROSS THE REGION. THIS COMBINED WITH
FORECAST MARGINAL MID LEVEL LAPSE RATES WILL LIMIT UPDRAFT
ACCELERATIONS. ALSO...WHILE LOW LEVEL WINDS ARE SUFFICIENT FOR
ISOLATED SUPERCELL STORMS AND A FEW TORNADOES...THEY DO NOT APPEAR
AT THIS TIME TO INCREASE CONCERN FOR SIGNIFICANT DAMAGING WINDS
/GREATER THAN 65KT GUSTS/ OR STRONG TORNADOES. LARGE HAIL THREAT IS
ALSO UNCERTAIN DUE TO THE WEAK LAPSE RATES ALOFT. ALL OF THESE
FACTORS HAVE LED TO THE DECISION TO MAINTAIN THE ONGOING PROBABILITY
AND CATEGORICAL OUTLOOK. AN UPGRADE TO MODERATE RISK WILL ONCE
AGAIN BE CONSIDERED AT 1630 UTC.

...TX/OK...
NORTHWEST FLOW ALOFT WILL PERSIST OVER THE CENTRAL HIGH PLAINS THIS
AFTERNOON...WHILE INCREASINGLY STRONG SOUTHERLY LOW LEVEL WINDS
TRANSPORT MOISTURE BACK INTO PARTS OF THE TX/OK PANHANDLES.
FORECAST SOUNDINGS FOR LATE AFTERNOON SUGGEST A DEEP-MIXED BOUNDARY
LAYER AND MLCAPE VALUES AROUND 1500 J/KG. PRESENT INDICATIONS ARE
THAT A FEW HIGH-BASED SUPERCELL STORMS WILL BE POSSIBLE THIS EVENING
ACROSS THE SLIGHT RISK AREA. LARGE HAIL AND DAMAGING WINDS WILL BE
THE MAIN THREAT.

..HART/BOTHWELL.. 06/01/2012

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