SPC AC 070448
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1048 PM CST THU DEC 06 2007
VALID 071200Z - 081200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
LONG-ADVERTISED EVOLUTION OF MAJOR SYNOPTIC TROUGH ACROSS WRN CONUS
-- PROGGED FOR UPCOMING WEEKEND -- WILL COMMENCE WITH STRENGTHENING
SHORTWAVE TROUGH NOW APCHG CA COAST. THIS FEATURE IS FCST TO MOVE
SEWD THEN EWD ACROSS CENTRAL/SRN CA AND NV THROUGH 8/00Z. UPSTREAM
SPEED MAX THEN SHOULD DIG SSEWD AND MAINTAIN STRONG TROUGHING ACROSS
GREAT BASIN...AS LEAD SHORTWAVE EJECTS NEWD OVER CENTRAL ROCKIES.
AT SFC...COLD FRONT -- NOW EVIDENT FROM SRN MN TO CENTRAL HIGH
PLAINS -- IS FCST TO MOVE SEWD AND MERGE WITH OLDER BAROCLINIC ZONE
NOW ANALYZED ACROSS EXTREME NRN GULF OF MEXICO AND S TX. BY
8/12Z...THIS WILL YIELD WAVY FRONTAL ZONE FROM VICINITY LOWER OH
VALLEY SWWD OVER RED RIVER REGION OF TX/OK...THEN NWWD INTO
STRENGTHENING LEE CYCLONE OVER SERN CO. PRIND GULF MOISTURE RETURN
AND INSTABILITY EACH WILL BE TOO WEAK TO SUPPORT TSTM POTENTIAL
INVOF THIS FRONT DAY-1.
...SRN GREAT BASIN REGION...
PRIND MRGL GEN THUNDER OUTLOOK EXISTS WHERE ZONE OF STRONGEST LARGE
SCALE ASCENT ALOFT...JUST PRECEDING EJECTING CA/NV
PERTURBATION...MAY SUPPORT ENVIRONMENT CONDUCIVE TO
ISOLATED/SPORADIC LIGHTNING. OPERATIONAL SPECTRAL AND NAM EACH
INDICATE SMALL/TRANSIENT POCKETS OF SUFFICIENTLY STEEP LOW-MIDLEVEL
LAPSE RATES TO SUPPORT MUCAPES 100-250 J/KG ACROSS SRN PORTIONS
NV/UT AND PERHAPS NWRN AZ -- PRIMARILY IN 7/18Z-8/03Z TIME FRAME.
MODIFIED NAM-KF SOUNDINGS BEAR THIS OUT...WITH VERY SLENDER CAPE
PROFILES JUST REACHING INTO AMBIENT LAYERS COLDER THAN ABOUT -20 DEG
C...AND SREF GUIDANCE ALSO INDICATES SOME THUNDER POTENTIAL OVER
PARTS OF THIS REGION.
..EDWARDS.. 12/07/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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