SPC AC 121240
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0640 AM CST WED JAN 12 2011
VALID 121300Z - 131200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A DEEP CYCLONE WILL CROSS SE MA THIS MORNING AND CONTINUE NEWD TO
THE GULF OF MAINE THIS AFTERNOON. STRONG ASCENT IN THE EXIT REGION
OF THE UPPER JET AND ON THE NOSE OF THE MIDLEVEL DRY SLOT HAS
CONTRIBUTED TO WEAK MIDLEVEL INSTABILITY...PER THE 150 J/KG MUCAPE
BASED AT 700 MB IN THE 12Z CHH SOUNDING. A FEW MORE LIGHTNING
STRIKES WILL BE POSSIBLE THIS MORNING ACROSS THE ERN MA AREA PRIOR
TO THE CYCLONE PROGRESSING OFFSHORE THIS AFTERNOON.
OTHERWISE...A COLD/DRY CONTINENTAL AIR MASS COVERS THE MAJORITY OF
THE CONUS AND WILL PRECLUDE DEEP CONVECTION. A SHORTWAVE TROUGH
WILL APPROACH THE COASTS OF WA/ORE/NRN CA NEAR THE END OF THE
PERIOD. NAM AND GFS FORECAST SOUNDINGS SHOW SOME POTENTIAL FOR WEAK
ELEVATED INSTABILITY NEAR THE COAST BY ABOUT 12Z.
HOWEVER...MIDLEVEL TEMPERATURES WILL NOT BE PARTICULARLY COLD AND
THE SHORTWAVE TROUGH IS MOVING INTO THE MEAN RIDGE POSITION NEAR THE
PAC COAST...THUS THE THUNDERSTORM THREAT APPEARS TOO MARGINAL TO
WARRANT AN OUTLOOK AREA.
..THOMPSON/HURLBUT.. 01/12/2011
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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