SPC AC 260544
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1144 PM CST MON FEB 25 2008
VALID 271200Z - 281200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
PROGRESSIVE MID/UPPER LEVEL PATTERN FCST ACROSS CONUS THROUGH
PERIOD. POSITIVELY TILTED SHORTWAVE TROUGH -- NOW EXTENDING FROM IL
SWWD ACROSS SRN PLAINS -- IS EXPECTED TO MOVE OFFSHORE BEFORE
BEGINNING OF PERIOD. UPSTREAM PERTURBATIONS -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER SRN WY/ERN UT...AND OVER MN/SD...ARE
FCST TO DIG SEWD AND REINFORCE SYNOPTIC TROUGHING ACROSS ERN CONUS.
AT SFC...CYCLONE INITIALLY OVER LOWER OH VALLEY WILL LIFT NEWD
TOWARD MAINE COAST BY BEGINNING OF PERIOD...THEN EJECT RAPIDLY
ACROSS CANADIAN MARITIME PROVINCES. TRAILING COLD FRONT SHOULD BE
SWEEPING SEWD ACROSS S FL BY 27/12Z...AND SHOULD EXIT FL KEYS BEFORE
17/18Z.
...S FL AND KEYS...
SWD EXTENSION OF REGIME DESCRIBED IN DAY-1 OUTLOOK MAY AFFECT
PORTIONS EXTREME SRN FL AND KEYS DURING FIRST FEW HOURS OF
PERIOD...BEFORE COLD FROPA AND SUBSEQUENT CAA REMOVE FAVORABLY
UNSTABLE AIR MASS. UPPER 60S/LOW 70S F SFC DEW POINTS AND LACK OF
CINH EACH WILL OFFSET WEAK LAPSE RATES ALOFT...ENOUGH TO YIELD
500-1000 J/KG MLCAPE ROOTED IN MOIST/MARINE BOUNDARY LAYER. LOW
LEVEL WINDS WILL BE VEERING...AND NEARLY PARALLEL TO FLOW THROUGH
DEEP TROPOSPHERIC LAYER ALOFT. THIS INDICATES BOTH LIMITED
CONVERGENCE IN FRONTAL ZONE...AND LINEAR MODE TO ANY ONGOING
CONVECTION ALONG/AHEAD OF FRONT. SUFFICIENT SPEED SHEAR AND BULK
SHEAR MAY LINGER TO SUPPORT SOME CONCERN FOR STG-SVR CONVECTIVE
GUSTS.
..EDWARDS.. 02/26/2008
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
|
