SPC AC 151704
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1204 PM CDT SUN MAR 15 2009
VALID 161200Z - 171200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
WEAK POSITIVELY TILTED MID-LEVEL TROUGH WILL SHIFT EWD FROM THE
LOWER/MID MS VALLEY REGION EWD TO THE ATLANTIC COASTAL STATES
DURING THIS FORECAST PERIOD. ZONAL FLOW WILL COVER THE CONUS BEHIND
THIS SYSTEM...WHILE A SERIES OF SHORTWAVE IMPULSES...LOCATED WITHIN
A LARGE TROUGH LOCATED OVER THE NERN PACIFIC/WRN CANADA...WILL EJECT
NEWD ACROSS THE PACIFIC NW/NRN ROCKIES. AT THE SURFACE...A WEAK
FRONT WILL MOVE SLOWLY SEWD ACROSS THE FL PENINSULA...WITH
HIGH PRESSURE COVERING THE CENTRAL AND ERN PORTIONS OF THE CONUS
BEHIND THE FRONT.
...SERN STATES...
LARGE SCALE FORCING ASSOCIATED WITH WEAK UPPER TROUGH AND ISENTROPIC
LIFT ABOVE SURFACE FRONT IS EXPECTED TO EXPAND AND SPREAD
CONVECTION...CURRENTLY OVER PORTIONS OF THE NWRN GULF...NEWD INTO
THE CENTRAL GULF STATES TONIGHT...AND THEN SHIFT EWD ACROSS THE
REGION ON MON. DEEP SWLY FLOW ALOFT WILL RESULT IN CONTINUED WEAK
LAPSE RATES. ALSO...SINCE THE UPDRAFT ROOTS ARE EXPECTED TO BE
SITUATED ABOVE THE COOLER BOUNDARY LAYER...THREAT FOR ANY SEVERE
THREAT APPEARS MINIMAL.
...PAC NW COAST...
STRONGLY WLY ONSHORE FLOW WILL RESULT IN WIDESPREAD PRECIPITATION
ACROSS THE NORTHWEST QUARTER PORTIONS OF THE COUNTRY ON MONDAY.
WHILE INSTABILITY IS EXPECTED TO BE EXTREMELY WEAK...THE COMBINATION
OF VERY STEEP LAPSE RATES FROM THE SURFACE TO 550 MB AND OROGRAPHIC
LIFT MAY BE SUFFICIENT FOR A FEW LIGHTNING STRIKES. THE PRIMARY
THREAT WILL BE LOCATED NEAR THE HIGHER TERRAIN OF COASTAL WA...WHERE
500 MB TEMPERATURES WILL RANGE FROM -30C TO -35C.
..IMY.. 03/15/2009
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z