SPC AC 231636
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1036 AM CST SAT DEC 23 2006
VALID 231630Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTH TEXAS THROUGH
EARLY TONIGHT....
...SYNOPSIS...
MID/UPPER LEVEL LOW OVER N CENTRAL MEXICO IS FORECAST TO MOVE SEWD
AND EWD TO JUST SOUTH AND SOUTHWEST OF THE MIDDLE RIO GRANDE VALLEY
THROUGH THE PERIOD. MEANWHILE...STRONG BAND OF WESTERLIES WILL
EXTEND OVER THE NRN THIRD OF THE U.S. AS LAST MID/UPPER LEVEL TROUGH
SKIRTS NEWD FROM THE GREAT LAKES INTO QUEBEC...AND NEXT MID/UPPER
LEVEL TROUGH MOVES FROM WRN CANADA AND THE PACIFIC NORTHWEST AND
ACROSS THE NRN PLATEAU. SURFACE RIDGING EXTENDS FROM OVER THE
CENTRAL INTERMOUNTAIN REGION SEWD INTO THE CENTRAL GULF STATES.
THUS...SFC LOW ASSOCIATED WITH MEXICO MID/UPPER LEVEL LOW IS
EXPECTED TO MOVE SEWD ACROSS NERN MEXICO WITH AN INVERTED SFC TROUGH
MOVING THRU EXTREME S TX TODAY AND EARLY TONIGHT.
...EXTREME SOUTH TEXAS...
A FEW STRONG ELEVATED THUNDERSTORMS ARE OCCURRING ALREADY ACROSS S
TX THIS MORNING WITHIN WEAK H85 THERMAL AXIS. MORNING RAOB DATA
NOTES DEEP LAYER SHEAR PROFILES IN THE HODOGRAPHS WITH VALUES AROUND
60 KT. THIS HAS PROVED TO BE SUFFICIENT FOR ROTATING STORMS ABOVE
COOL BOUNDARY LAYER. PROBLEM EXISTS THAT LAPSE RATES HAVE BEEN VERY
MARGINAL RUNNING AROUND 6.5 C/KM AT KBRO AND AROUND 7 C/KM AT KCRP.
AIR MASS IS MARGINALLY UNSTABLE ACROSS THE SRN TIP OF TX WITH MUCAPE
AROUND 500 J/KG AND WITH THE CONSIDERABLE CLOUD COVER...IT LOOKS
LIKE THAT MAY BE THE BEST IN THE WAY OF THERMODYNAMICS FOR THE
PERIOD.
THUS...WITH ELEVATED ACTIVITY EXPECTED THROUGH EARLY TONIGHT...IT
LOOKS LIKE THE MAIN THREAT WITH THUNDERSTORM ACTIVITY DURING THE
PERIOD WILL BE FOR HAIL AND SOME STRONG WINDS.
..MCCARTHY.. 12/23/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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