SWODY2
SPC AC 101726
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1126 AM CST MON NOV 10 2008
VALID 111200Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS TUE/TUE NIGHT ACROSS PARTS OF
TX/WRN GULF COASTAL AREAS....
...SYNOPSIS...
AS A STRONG ZONAL PACIFIC JET NOSES INTO THE SOUTHERN CANADIAN
ROCKIES LATER TODAY THROUGH TUESDAY...MODELS INDICATE THAT A
MID-LEVEL CLOSED LOW...EMBEDDED WITHIN THE SOUTHERN BRANCH OF
DOWNSTREAM SPLIT POLAR WESTERLIES...WILL LIFT NORTHEAST OF THE
CENTRAL PLAINS. AT THE SAME TIME...A MUCH LARGER MID/UPPER CLOSED
LOW/TROUGH...WITHIN THE NORTHERN BRANCH...IS PROGGED TO CONTINUE
GRADUALLY LIFTING OUT OF QUEBEC AND THE NORTHEASTERN STATES THROUGH
THE CANADIAN MARITIMES.
IN THE WAKE OF THE LATTER FEATURE...A LARGE COLD/STABLE SURFACE
RIDGE IS FORECAST TO BE SLOW TO RETREAT EAST OF THE MISSISSIPPI
VALLEY. AND...SURFACE CYCLOGENESIS ASSOCIATED WITH THE SOUTHERN
BRANCH SYSTEM IS EXPECTED TO REMAIN WEAK. AN ASSOCIATED SURFACE
COLD FRONT MAY BEGIN TO SURGE SOUTHWARD TOWARD THE TEXAS COAST AND
RIO GRANDE VALLEY. BUT...IT APPEARS THAT SOUTHERLY PRE-FRONTAL
WINDS WILL MAINTAIN A MOIST INFLOW OF MOISTURE OFF THE WESTERN GULF
OF MEXICO THROUGH EASTERN TEXAS AND PARTS OF THE LOWER MISSISSIPPI
VALLEY/OZARK PLATEAU REGION.
...SOUTH CENTRAL STATES...
A RETURN FLOW OF MOISTURE CHARACTERIZED BY 65F+ SURFACE DEW POINTS
IS ONGOING ACROSS THE WESTERN GULF COAST. BUT...MODELS SUGGEST THAT
BOUNDARY LAYER MOISTENING/DESTABILIZATION WILL GENERALLY BE CONFINED
TO PARTS OF CENTRAL/EASTERN TEXAS THROUGH THIS PERIOD... DUE TO THE
CONTINUING STABILIZING INFLUENCE OF THE EASTERN STATES RIDGE. ABOVE
THE STABLE LAYER...SUBSTANTIVE MOISTENING IS POSSIBLE AS FAR NORTH
AS THE WARM SECTOR OF THE WEAKENING SURFACE LOW MIGRATING FROM THE
EAST CENTRAL PLAINS INTO THE LOWER MISSOURI VALLEY. AND...IT IS
POSSIBLE THAT ZONES OF STEEPER ISENTROPIC ASCENT MAY BE ACCOMPANIED
BY SCATTERED THUNDERSTORM ACTIVITY CAPABLE OF PRODUCING SOME SMALL
HAIL. HOWEVER...ANY APPRECIABLE SEVERE POTENTIAL IS EXPECTED TO BE
LIMITED TO AREAS CLOSER TO THE GULF COAST...WHERE MIXED LAYER CAPE
MAY REACH 1000-2000 J/KG.
VIGOROUS CONVECTIVE DEVELOPMENT MAY BE ONGOING EARLY TUESDAY ACROSS
PARTS OF CENTRAL INTO NORTHEAST TEXAS...SUPPORTED BY FORCING
ASSOCIATED WITH AN IMPULSE ROTATING AROUND THE SOUTHERN BRANCH
CLOSED LOW. THIS FORCING IS PROGGED TO SHIFT NORTHEASTWARD
INTO/THROUGH THE MIDDLE MISSISSIPPI VALLEY BY MIDDAY...AND POTENTIAL
CONVECTIVE TRENDS THEREAFTER ARE UNCLEAR. IF MID-LEVEL
SUBSIDENCE/WARMING IS NOT SUFFICIENT TO SUPPRESS STORM DEVELOPMENT
...DEEP LAYER SHEAR IS EXPECTED TO REMAIN FAVORABLE FOR ORGANIZED
SEVERE CONVECTION AND SUPERCELLS IN THE PRESENCE OF MODERATE
INSTABILITY THROUGH THE REMAINDER OF THE DAY.
INTO TUESDAY NIGHT...VARIABILITY INCREASES AMONG MODEL DATA
CONCERNING THE NEXT IMPULSE DIGGING INTO AND PROGRESSING THROUGH THE
BASE OF THE SOUTHERN BRANCH TROUGH. BUT...IT APPEARS POSSIBLE THAT
ASSOCIATED FORCING COULD SUPPORT A RENEWED INCREASE IN STRONG/SEVERE
THUNDERSTORM ACTIVITY...PARTICULARLY ACROSS PARTS OF THE MID/UPPER
TEXAS COASTAL PLAIN.
..KERR.. 11/10/2008
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