Day-3 Outlook from SPC has slight risk along Gulf Coast
Posted: Mon Dec 20, 2004 10:10 am
As expected, the SPC has placed a slight risk along many of the Gulf states, as warm moist air from the Gulf makes it's way back to the north behind the retreating cold high in the SE. The powerful upper system digging east-northeast from the SW, in addition to a favorably coupled upper jet system, may lead to strong and severe storms on Wednesday (and perhaps even Tuesday). Shear will be high, low-level temps and moisture will be setup, although instability won't be great. The baroclinic zone will also be strengthening throughout the day given increasingly cold air behind the front and warmer air to the SE. Here is their discussion:
HERE IS A SLGT RISK OF SVR TSTMS FROM E TX EWD TO PARTS OF GA /
NRN FL...
...SYNOPSIS...
SHORT-WAVE TROUGH INITIALLY EXPECTED OVER THE SRN ROCKIES / SRN
PLAINS IS FORECAST TO MOVE CYCLONICALLY EWD AROUND THE BASE OF THE
LARGER-SCALE TROUGH...REACHING THE TN VALLEY REGION BY LATE IN THE
PERIOD. THIS FEATURE IS FORECAST TO BE ACCOMPANIED BY AN 80-PLUS KT
JET STREAK...WHICH WILL CONTRIBUTE TO DEEP-LAYER SHEAR ACROSS THE
SERN U.S. SUPPORTIVE OF SEVERE STORMS.
AT THE SURFACE...FRONT INITIALLY FORECAST FROM NERN TX NEWD INTO THE
TN VALLEY SHOULD SHARPEN AS TROUGH APPROACHES. LOW IS FORECAST TO
DEEPEN / SHIFT NEWD ALONG THE BAROCLINIC ZONE...WITH BOTH THE ETA
AND GFS FORECASTING LOW OVER THE UPPER OH VALLEY AND SHARP FRONT
EXTENDING SWD ALONG THE APPALACHIAN REGION AND INTO THE ERN GULF BY
THE END OF THE PERIOD.
...UPPER TX COAST EWD ACROSS THE GULF COAST STATES...
SLY FLOW IN WARM SECTOR AHEAD OF COLD FRONT WILL CONTINUE TO ADVECT
INCREASINGLY-MOIST GULF AIR NWD INTO THE SERN CONUS. WITH FRONT
LIKELY SERVING AS A FOCUS FOR CONVECTIVE DEVELOPMENT...COMBINATION
OF MOIST / MARGINALLY-UNSTABLE AIRMASS AND INCREASINGLY-STRONG
DEEP-LAYER WIND FIELD SHOULD SUPPORT AT LEAST SOME THREAT FOR SEVERE
STORMS THROUGH THE PERIOD. INITIAL THREAT APPEARS TO EXIST ACROSS E
TX / LA DURING THE FIRST HALF OF THE PERIOD...BUT SHOULD SHIFT EWD
ACROSS THE LOWER MS VALLEY THROUGH THE EVENING. THOUGH DETAILS
REGARDING STORM INITIATION AND POSSIBLE MODE REMAIN
UNCLEAR...OVERALL ENVIRONMENT AT THIS POINT APPEARS SUPPORTIVE OF
BOTH LINEAR / DAMAGING WIND THREAT AS WELL AS A POTENTIAL FOR
SUPERCELLS / ISOLATED TORNADOES.
..GOSS.. 12/20/2004
