SPC AC 080546
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1146 PM CST WED JAN 07 2009
VALID 081200Z - 091200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
UPPER AIR PATTERN -- DOMINATED INITIALLY BY PRONOUNCED RIDGING OVER
WRN STATES AND ERN CONUS TROUGH -- IS FCST TO DEAMPLIFY SOMEWHAT
ACROSS CONUS DURING THIS PERIOD. STG SHORTWAVE TROUGH -- EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER NE PACIFIC WATERS BETWEEN 135W-140W AS
OF 8/05Z -- IS FCST TO MOVE INLAND WA/ORE/NRN CA DURING FIRST FEW
HOURS OF PERIOD...THEN EWD OVER NRN ROCKIES AND GREAT BASIN REGIONS.
BY 9/12Z...TROUGH SHOULD EXTEND FROM ANCHORING VORTICITY MAX -- AND
POSSIBLY NEARLY CLOSED 500 MB LOW OVER ND -- SWWD ACROSS UT. BROAD
AREA OF LOW LEVEL CYCLOGENESIS WILL OCCUR IN RESPONSE OVER CENTRAL
PLAINS...BY END OF PERIOD. ASSOCIATED LOW LEVEL WAA/ISENTROPIC LIFT
REGIME SHOULD BE QUITE STG...BUT TOO DRY TO SUPPORT GEN THUNDER
POTENTIAL DURING THIS PERIOD.
TSTMS AHEAD OF ATLANTIC SEABOARD TROUGH SHOULD DEVELOP/REMAIN
OFFSHORE WHERE RELATIVELY WARM GULF STREAM WATERS ENHANCE
POSTFRONTAL BOUNDARY LAYER THETAE AND STEEPEN LAPSE RATES ENOUGH TO
SUPPORT DEEP CONVECTION.
...INLAND PACIFIC NW TOWARD NRN ROCKIES...
AS HEIGHT FALLS AND DPVA ALOFT SPREAD EWD ACROSS REGION IN ADVANCE
OF SHORTWAVE TROUGH...COLLOCATED POCKETS OF AT LEAST MRGL
LOW-MIDLEVEL MOISTURE WILL SUPPORT ISOLATED TO WIDELY SCATTERED
THUNDER...MAINLY AFTERNOON INTO EARLY EVENING. BUOYANCY WILL BE
LIMITED BY COOLNESS OF SFC TEMPS...HOWEVER COMPENSATING COLD AIR
ALOFT IN FCST SOUNDINGS SHIFTS ENTIRE THERMODYNAMIC PROFILE LEFTWARD
ENOUGH TO MAINTAIN STEEP LOW LEVEL LAPSE RATES AND POCKETS OF MLCAPE
TO NEAR 200 J/KG. ONLY SLGT ADJUSTMENTS TO NEAR-SFC THETAE ARE
NEEDED TO MOVE BUOYANT PROFILE UP AND DOWN ON SOUNDINGS...AND INTO
OR OUT OF IDEAL THERMAL ICING ZONES FOR LIGHTNING PRODUCTION. WHILE
THUNDER POTENTIAL APPEARS MRGL ATTM...PRIND PROBABILITIES REMAIN
VERY NEAR 10 PERCENT OVER OUTLOOKED AREA.
..EDWARDS.. 01/08/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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