SPC AC 250535
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1135 PM CST TUE NOV 24 2009
VALID 261200Z - 271200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
THANKSGIVING WEATHER INTEREST WILL BE ON THE EVOLUTION OF A
DEEP/COLD TROUGH OVER THE ERN PARTS OF THE COUNTRY. THIS TROUGH
WILL BECOME NEGATIVELY-TILTED OVER THE UPR OH VLY THURSDAY AFTN AND
THEN TRANSLATE ENE INTO THE MID-ATLC REGION...ACCOMPANIED BY
180-METER/12-HR HEIGHT FALLS. NWLY FLOW IN WAKE OF THE SYSTEM WILL
FORCE A CDFNT WELL S INTO THE GULF OF MEXICO AND FL STRAITS BY
THURSDAY NIGHT.
UPSTREAM...A NEW UPR TROUGH WILL ARRIVE ONSHORE THE PAC NW WHILE A
SUB-TROPICAL DISTURBANCE MIGRATES OVER NRN MEXICO.
...MID-ATLC REGION...
STRONG PV-ANOMALY AND MID-LVL LAPSE RATES APCHG 7 DEG C PER KM WILL
ACCOMPANY THE TROUGH TRANSITION TO NEGATIVE-TILT ACROSS PARTS OF THE
REGION THURSDAY AFTN/NIGHT. FCST SOUNDINGS EXHIBIT A FEW HOURS OF
SMALL ELEVATED CAPE...AND GIVEN SUCH STRONG UVV EXPECTED...SPORADIC
BURSTS OF LIGHTNING WILL LIKELY OCCUR.
...CSTL PAC NW...
STEEPENING LAPSE RATES IN THE MOIST...POST-FRONTAL REGIME WILL BE
FAVORABLE FOR SHOWERS THURSDAY NIGHT ACROSS THE REGION. MID-LVL
TEMPERATURES ACCOMPANYING THE UPR TROUGH APPROACH MINUS 30 DEG C AND
CLOUD-TOPS WILL PROBABLY BE SUFFICIENTLY HIGH TO PRODUCE LIGHTNING.
..RACY.. 11/25/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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