SPC AC 010823
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0223 AM CST THU JAN 01 2009
VALID 031200Z - 041200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A LARGE UPPER TROUGH MOVING ACROSS THE WRN U.S. IS FORECAST TO
AMPLIFY FURTHER THIS PERIOD...WITH TROUGHING EXPANDING ACROSS THE
ENTIRE WRN HALF OF NOAM BY THE END OF THE PERIOD.
MODEL DIFFERENCES IN HANDLING THIS FEATURE AND THE ASSOCIATED
SURFACE REFLECTION INCREASE THIS PERIOD...BUT EXPECT A LOW OVER THE
CENTRAL HIGH PLAINS EARLY IN THE PERIOD TO SHIFT ESEWD INTO OK
THROUGH THE AFTERNOON...BEFORE REDEVELOPING NEWD INTO THE MIDWEST/OH
VALLEY REGION LATE. AS THIS OCCURS...A SURFACE COLD FRONT WILL
SWEEP SEWD ACROSS THE S CENTRAL CONUS...POSSIBLY PROVIDING A FOCUS
FOR DEEP CONVECTION THROUGH THE END OF THE PERIOD.
...WRN AND CENTRAL GULF COAST REGION NWD INTO THE ARKLATEX...
MODEL DIFFERENCES THIS PERIOD COMPLICATE ASSESSMENT OF THE
CONVECTIVE POTENTIAL OVER THE S CENTRAL CONUS. THE NAMKF SUGGESTS A
CAPPED BOUNDARY LAYER AND ASSOCIATED LACK OF CONVECTION THROUGH THE
PERIOD...WHILE THE GFS AND NAM -- TO VARYING DEGREES -- DEPICT
CONVECTIVE DEVELOPMENT/EXPANSION FROM E TX EWD AND NEWD THROUGH THE
PERIOD. THE GFS -- WITH A CONSISTENTLY STRONGER DEPICTION OF THE
UPPER TROUGH AND ASSOCIATED SURFACE LOW -- REMAINS THE MORE BULLISH
MODEL IN TERMS OF CONVECTIVE POTENTIAL. MEANWHILE...THE NAM STRIKES
SOMEWHAT OF A MIDDLE GROUND BETWEEN THE GFS AND NAMKF AS IT
MAINTAINS SOME CAPPING THROUGH AT LEAST THE FIRST HALF OF THE
PERIOD...AND ALSO SUGGESTS THAT ANY EVENTUAL DEVELOPMENT SHOULD TEND
TO REMAIN ELEVATED.
ATTM...WILL INTRODUCE A RATHER LARGE/LOW-PROBABILITY THREAT
AREA...CENTERED OVER E TX/LA. IT APPEARS THAT THE PRIMARY THREAT
WOULD EXIST LATER IN THE PERIOD...MAINLY FROM THE SABINE RIVER
VALLEY EWD. HOWEVER...WITH THE GFS CONSISTENT FOR SEVERAL RUNS IN
IMPLYING THE POTENTIAL FOR DAYTIME SURFACE-BASED STORMS OVER E
TX...WILL INCLUDE THIS REGION IN THE THREAT AREA AS WELL. WHILE
POTENTIAL FOR HAIL SHOULD REMAIN QUITE LOW GIVEN AN OVERALL LACK OF
INSTABILITY...THREAT FOR LOCALLY-DAMAGING WINDS OR AN ISOLATED
TORNADO APPEARS JUST HIGH ENOUGH ATTM TO WARRANT THE INCLUSION OF A
SEE TEXT/5% PROBABILITY AREA.
..GOSS.. 01/01/2009
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0830Z
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