ACUS02 KWNS 101705
SWODY2
SPC AC 101703
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1103 AM CST SAT NOV 10 2007
VALID 111200Z - 121200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
A PROGRESSIVE...SPLIT FLOW REGIME WILL BE PRESENT OVER THE CONUS
DURING THE DAY TWO PERIOD. NRN BRANCH OF POLAR WESTERLIES WILL
FEATURE AN ACTIVE WAVE TRAIN FROM THE NERN PACIFIC EWD INTO CNTRL
CANADA...WHILE LOWER LATITUDE IMPULSES TRANSLATE ACROSS NRN MEXICO
INTO TX...AND FROM THE ERN PACIFIC INTO THE LOWER CO VALLEY. IN THE
LOW LEVELS...WARM FRONT /MOST NOTABLE ABOVE THE BOUNDARY LAYER/ WILL
PROGRESS EWD FROM THE MS RIVER VALLEY THROUGH OH VALLEY AND UPPER
MIDWEST IN ADVANCE OF COLD FRONT PUSHING SEWD THROUGH THE NRN AND
CNTRL PLAINS STATES.
..MID MS VALLEY INTO OH VALLEY...
CLUSTERS OF ELEVATED TSTMS ARE EXPECTED TO BE ONGOING SUNDAY MORNING
INVOF AND TO THE E OF SFC-850 MB WARM FRONT...DRIVEN LARGELY BY WAA
AND ISENTROPIC ASCENT ALONG NOSE OF 30-35 KT SWLY LLJ. THIS
ACTIVITY WILL LIKELY CONTINUE THROUGH THE DAY EWD INTO THE OH VALLEY
IN CONJUNCTION WITH EWD MIGRATION OF WARM FRONT AND LLJ AXIS.
FORECAST SOUNDINGS INDICATE THE PRESENCE OF MUCAPES OF 500-1000 J/KG
ABOVE BOUNDARY LAYER AND SOME STORMS WILL BE CAPABLE OF SMALL HAIL.
HOWEVER...RATHER WEAK MID LEVEL LAPSE RATES AND MARGINAL CLOUD
BEARING SHEAR SHOULD LIMIT ANY SEVERE THREAT.
..TX/OK...
MORNING OBSERVATIONAL DATA INDICATE THAT AT LEAST MODEST BOUNDARY
LAYER MOISTURE HAS RETURNED NWD THROUGH CNTRL/ERN TX INTO CNTRL OK
WITH SURFACE DEWPOINTS RANGING FROM LOW/MID 50S OVER CNTRL OK TO
65-70F FROM CNTRL TX TO THE TX COAST. WHILE LOW-LEVEL TRAJECTORIES
ARE FORECAST TO REMAIN SLY/SELY...LATEST MODEL GUIDANCE SUGGESTS
THAT CONSIDERABLE BOUNDARY LAYER MIXING WILL RESULT IN LITTLE
INCREASE IN MOISTURE CONTENT THROUGH SUNDAY NIGHT. MOREOVER...
FORECAST SOUNDINGS INDICATE THAT A PRONOUNCED CAP WILL LIKELY
INHIBIT ANY DIURNAL STORM DEVELOPMENT...EXCEPT PERHAPS INVOF COMPLEX
TERRAIN OVER SWRN TX SUNDAY AFTERNOON/EVENING WHERE ISOLATED STORM
DEVELOPMENT WILL BE POSSIBLE.
TSTMS /LIKELY ELEVATED/ ARE EXPECTED TO BECOME MORE LIKELY SUNDAY
NIGHT FROM PARTS OF W-CNTRL TX INTO S-CNTRL/SERN OK AS LARGE-SCALE
FORCING FOR ASCENT INCREASES AHEAD OF APPROACHING SHORT WAVE TROUGH.
FORECAST SOUNDINGS SUGGEST THAT ANY DEVELOPING STORMS WILL BE ROOTED
ABOVE 850-700 MB CAP WITHIN MARGINALLY UNSTABLE ENVIRONMENT WITH
MUCAPES OF 500-900 J/KG. NO SEVERE WEATHER IS ANTICIPATED.
..SIERRA NEVADAS INTO LOWER CO VALLEY...
CONSIDERABLE HEIGHT FALLS/MID-LEVEL COOLING WILL SUPPORT STEEPENING
LAPSE RATES AND THE DEVELOPMENT OF WEAK CONVECTIVE INSTABILITY IN
ASSOCIATION WITH SHORT WAVE TROUGH DIGGING SEWD THROUGH THE REGION.
A FEW TSTMS WILL BE POSSIBLE SUNDAY AFTERNOON AND NIGHT WHERE
STRONGER LARGE-SCALE FORCING FOR ASCENT ACTS ON WEAKLY UNSTABLE
ENVIRONMENT.
.MEAD.. 11/10/2007
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