SPC AC 180552
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1152 PM CST SUN DEC 17 2006
VALID 191200Z - 201200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
IN MID-UPPER LEVELS...HIGHLY AMPLIFIED AND POSITIVELY TILTED TROUGH
IS EVIDENT IN MOISTURE CHANNEL IMAGERY FROM WY SWWD ACROSS SRN CA
AND OVER PACIFIC WATERS WELL OFFSHORE NRN BAJA. AS OFFSHORE SPEED
MAX DIGS INTO BASE OF TROUGH...THROUGH DAY-1...CLOSED AND
TEMPORARILY CUT-OFF LOW WILL DEVELOP INVOF CA/MEX BORDER. LAST
SEVERAL RUNS OF MOST OPERATIONAL MODELS AND SREF MEMBERS HAVE BEEN
CONSISTENT IN EJECTING THIS FEATURE NEWD ACROSS 4-CORNERS REGION
DURING WHAT IS NOW DAY-2 PERIOD...AND CONFIDENCE IN THIS SCENARIO IS
INCREASING WITH TIME.
AT SFC...COLD FRONT NOW ANALYZED FROM ERN IL SWWD ACROSS SERN
OK...NWRN TX AND SERN NM...IS FCST TO MOVE SWD INTO S-CENTRAL AND SW
TX THROUGH DAY-2. AMIDST INCREASING LOW LEVEL PRESSURE/HEIGHT FALLS
AND KINEMATIC RESPONSE...ASSOCIATED WITH EJECTING SWRN LOW -- WRN
PORTION OF FRONT MAY STALL AND RETREAT SLIGHTLY NWD ACROSS BIG BEND
AND TRANS-PECOS REGIONS OF W TX. DURING LATTER HALF OF
PERIOD...STRONG LOW LEVEL FRONTOGENESIS IS FCST OVER NM...WITH
RESULTING COLD FRONT SWEEPING EWD OVER MUCH OF SRN HIGH PLAINS BY
20/12Z.
...S-CENTRAL/SWRN CONUS TO CENTRAL HIGH PLAINS...
WIDELY SCATTERED TSTMS MAY BE ONGOING AT BEGINNING OF PERIOD OVER
PORTIONS W TX AND NM...AMIDST STRONG LOW LEVEL WAA REGIME AND
MOISTENING AIR MASS ABOVE SFC. THIS REGIME WILL CONTINUE THROUGH
MUCH OF DAYLIGHT AND EVENING HOURS...SHIFTING/SPREADING NWD AND EWD
AS AIR MASS CONTINUES TO MOISTEN. LIMITED BUOYANCY ALOFT AND
RELATIVELY STABLE AIR NEAR SFC SHOULD PRECLUDE ORGANIZED SVR
POTENTIAL DESPITE STRENGTHENING DEEP-LAYER SHEAR.
BRIEF VERTICAL JUXTAPOSITION OF SFC-BASED WARM SECTOR WITH FAVORABLE
VERTICAL SHEAR MAY OCCUR OVER PORTIONS SRN HILL COUNTRY AND
LOWER-MIDDLE RIO GRANDE VALLEY REGION OF S TX. HOWEVER...LIKELY
NEGATIVE FACTORS FOR SVR INCLUDE WEAK LOW LEVEL FORCING...AND
UNFAVORABLE MIDLEVEL LAPSE RATES THAT MAY DRASTICALLY LIMIT
BUOYANCY.
CONVECTIVE COVERAGE SHOULD INCREASE AFTER DARK ACROSS W TX -- MAINLY
ATOP RELATIVELY STABLE BOUNDARY LAYER AND IN ZONE OF STRONGEST LOW
LEVEL FRONTOGENETIC FORCING. THIS ACTIVITY MAY DEVELOP/BUILD EWD
AND NWD OVER PORTIONS WRN OK AND CENTRAL HIGH PLAINS BY END OF
PERIOD. SOME TSTMS OVER CENTRAL/SRN HIGH PLAINS MAY YIELD WINTER
PRECIP WHERE LOW LEVEL THERMAL STRATIFICATIONS ARE SUITABLE BENEATH
ELEVATED BUOYANT LAYER.
...4-CORNERS REGION...
ISOLATED TO WIDELY SCATTERED THUNDER IS POSSIBLE IN ZONE OF MOST
INTENSE LARGE SCALE ASCENT/COOLING...BENEATH AND IMMEDIATELY AHEAD
OF MID/UPPER LEVEL CYCLONE. ALTHOUGH LOW LEVEL THETAE WILL BE VERY
LIMITED...LOW-MIDLEVEL LAPSE RATES MAY BECOME STEEP ENOUGH TO
COMBINE WITH MRGL MOISTURE IN SUPPORT OF SHALLOW TSTMS -- SOME OF
WHICH MAY BE ACCOMPANIED BY GRAUPEL AND SNOW.
..EDWARDS.. 12/18/2006
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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