SPC AC 270628
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 AM CST WED DEC 27 2006
VALID 281200Z - 291200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A VIGOROUS SHORT WAVE IMPULSE NOW MOVING FROM CA TOWARD THE GREAT
BASIN IS FORECAST TO PRODUCE SUBSTANTIAL MID LEVEL HEIGHT FALLS OF
OVER 200 METERS PER 12 HOURS ACROSS THE SOUTHWEST THROUGH THE DAY 1
PERIOD. THE RESULTING LARGE SCALE FLOW AMPLIFICATION OVER THE WRN
U.S. WILL BRING ABOUT DEEP-LAYER CYCLOGENESIS NEAR THE FOUR CORNERS
REGION BY EARLY THURSDAY WITH ANOTHER MAJOR SNOWSTORM ON TAP FOR THE
CNTRL/SRN ROCKIES.
LEE-SIDE CYCLONE IS FORECAST TO DEEPEN ACROSS NERN NM AND MOVE EAST
TO THE TX/OK PNHDLS THROUGH THURSDAY EVENING. AT THE SAME...LATEST
GUIDANCE SUGGESTS STRONG LARGE SCALE FORCING ON THE CYCLONIC SHEAR
SIDE OF 50-75KT MID LEVEL JET WILL SPREAD EWD/NEWD ACROSS WEST TX
AND TOWARD THE RED RIVER. STRONG DYNAMIC FORCING ACTING ON
MARGINALLY UNSTABLE AIR MASS SHOULD RESULT IN INCREASING CONVECTION
FROM LATE THURSDAY THROUGH EARLY FRIDAY OVER THE SRN PLAINS.
...TX/OK..
MODEL RUNS THIS EVENING ARE CONTINUING A TREND NOTED LAST NIGHT IN
DEPICTING A SLIGHTLY DEEPER EVOLUTION TO THE LARGE SCALE TROUGH/LOW
OVER THE NEXT 48 HOURS. THE EWD PROGRESSION OF STRONGER LARGE SCALE
FORCING ASSOCIATED WITH DPVA AND SUBSEQUENT LEE-SIDE LOW DEVELOPMENT
WILL ALSO BE SLOWER TO OCCUR ONCE THE MID LEVEL SYSTEM CLOSES OFF
OVER AZ/NM. NONETHELESS...LOW LEVEL SLY FLOW IS FORECAST TO
STRENGTHEN CONSIDERABLY FROM THE WRN GULF ACROSS SRN PLAINS THROUGH
LATE DAY 1 IN RESPONSE TO LARGE SCALE FLOW AMPLIFICATION AND
ISALLOBARIC FORCING. LOW LEVEL JET IS FORECAST TO INCREASE TO OVER
50KT DURING THE DAY THURSDAY WITH MODELS INDICATING A STEADY
INCREASE IN LOW LEVEL MOISTURE AS GULF AIR MASS UNDERGOES
MODIFICATION.
SREF GUIDANCE INDICATES MEAN 850MB DEWPOINTS OF 4-8C EXTENDING FROM
THE TX GULF COAST TO NCNTRL TX BY LATE EVENING WITH A NARROW AXIS OF
WEAK MUCAPE RANGING FROM 200-500 J/KG. EXPECT A FEW STRONG BUT
ELEVATED STORMS TO ERUPT AS STRONG FORCING AND SHEAR DEVELOP EAST
WITH THE LARGE SCALE SYSTEM THROUGH LATE IN THE PERIOD. WITH LIMITED
INSTABILITY AND UPDRAFTS LIKELY ROOTED ABOVE THE BOUNDARY
LAYER...HAIL APPEARS TO BE THE PRIMARY CONCERN AT THIS TIME.
THE TREND TOWARD A SLOWER EMERGENCE OF STRONG FORCING ACROSS THE SRN
PLAINS SUGGESTS THAT ANY SEVERE HAIL THREAT WILL BE LIMITED TO THE
LATER HALF OF THE FORECAST PERIOD. FURTHERMORE...QUESTIONS REGARDING
THE QUALITY OF AVAILABLE MOISTURE AND RESULTANT INSTABILITY RESULT
IN GREATER UNCERTAINTY REGARDING THE DEVELOPMENT AND EXTENT OF
SEVERE STORMS. THUS...A LOWER PROBABILITY OUTLOOK APPEARS SUFFICIENT
AT THIS TIME.
..CARBIN.. 12/27/2006
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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