Wednesday, December 7, 2011

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 071238
SWODY1
SPC AC 071237

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0637 AM CST WED DEC 07 2011

VALID 071300Z - 081200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

AN INTENSE VORTICITY MAXIMUM AND ASSOCIATED 100+ KT MIDLEVEL JET
STREAK OVER THE LOWER MS VALLEY WILL EJECT NEWD TO OFF THE MID
ATLANTIC COAST THIS PERIOD WITH A CORRIDOR OF 12-HR HEIGHT FALLS AT
500 MB OF 150-200 M FORECAST ALONG SYSTEM TRACK. IN THE LOW
LEVELS...ELONGATED LOW PRESSURE ALONG THE BLUE RIDGE WILL
CONSOLIDATE INTO A DEEPENING SURFACE LOW WHICH WILL DEVELOP THROUGH
THE DELMARVA LATER THIS AFTERNOON AND EVENING...BEFORE UNDERGOING
SUBSTANTIAL DEEPENING OFF THE NEW ENGLAND COAST OVERNIGHT. THIS LOW
PRESSURE CENTER WILL MOVE IN TANDEM WITH A COLD FRONT WHICH WILL
ADVANCE THROUGH THE PIEDMONT AND COASTAL PLAINS BY TONIGHT.

...PORTIONS OF VA/NC INTO SRN PARTS OF MD/DE ...

AS MENTIONED ABOVE...LARGE-SCALE FORCING FOR ASCENT WILL INCREASE
MARKEDLY TODAY IN ADVANCE OF THE POTENT MIDLEVEL TROUGH AND
ASSOCIATED JET STREAK. AND GIVEN THE MOIST..PRE-FRONTAL AIR MASS IN
PLACE /I.E. PW VALUES APPROACHING 1.3-1.5 INCHES/...EXPECT AN
INCREASE IN SHOWERS WITH EMBEDDED TSTMS THIS AFTERNOON AND
EVENING...PRIMARILY ALONG SURFACE LOW TRACK. WIDESPREAD CLOUDS AND
POOR LAPSE RATES WILL LIMIT THE AMOUNT OF AIR MASS DESTABILIZATION
LATER TODAY WITH FORECAST SOUNDINGS SUGGESTING MLCAPE VALUES
GENERALLY LESS THAN 200-400 J/KG. WHILE THE WEAK INSTABILITY WILL
LIMIT THE POTENTIAL FOR AN ORGANIZED SEVERE WEATHER EPISODE...LOW
TORNADO AND WIND PROBABILITIES ARE WARRANTED GIVEN THE STRONG
FORCING FOR ASCENT AND VERTICAL SHEAR.

..MEAD/SMITH.. 12/07/2011

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