SWODY2
SPC AC 061643
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1143 AM CDT SAT OCT 06 2007
VALID 071200Z - 081200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
LATEST MODEL GUIDANCE CONTINUES TO INDICATE DIFFERENCES IN THE
EVOLUTION OF UPPER TROUGH AS IT PROGRESSES EWD INTO THE PLAINS
STATES. THE NAM/WRF MAINTAINS A POSITIVE TO NEUTRAL TILT TO THIS
SYSTEM WITH PRIMARY FEATURE BEING DEVELOPING UPPER LOW OVER ND/SRN
MANITOBA. IN CONTRAST...THE GFS SUGGESTS SYSTEM WILL BECOME
INCREASINGLY NEGATIVELY-TILTED...ALSO SHOWING UPPER LOW OVER
ND...BUT ALSO INDICATING THAT A STRONGER VORTICITY MAXIMUM WILL LIFT
NEWD INTO THE MID MO VALLEY. IN THE LOW LEVELS...PRIMARY SURFACE
LOW WILL PERSIST OVER THE UPPER MIDWEST/UPPER GREAT LAKES WITH
TRAILING COLD FRONT PUSHING SEWD THROUGH THE UPPER MS VALLEY...MID
MO VALLEY AND PARTS OF THE CNTRL AND SRN PLAINS.
..UPPER GREAT LAKES SWWD INTO THE SRN HIGH PLAINS...
BOUNDARY LAYER IS FORECAST TO REMAIN RELATIVELY MOIST AHEAD OF COLD
FRONT WITH DEWPOINTS COMMONLY IN THE 60S. HOWEVER...LAPSE RATES
WILL REMAIN RELATIVELY WEAK /NEAR MOIST ADIABATIC IN THE MID-LEVELS/
AND CONSIDERABLE CLOUDINESS IS EXPECTED IN WARM SECTOR. THESE
FACTORS SHOULD EFFECTIVELY LIMIT MLCAPES TO 1000-1500 J/KG.
TSTMS MAY BE ONGOING SUNDAY MORNING ALONG PORTIONS OF COLD FRONT
FROM THE UPPER MS VALLEY SWWD INTO THE CNTRL PLAINS. A GRADUAL
INCREASE IN STORM COVERAGE AND INTENSITY IS EXPECTED OVER THE COURSE
OF THE DAY AS FORCING FOR ASCENT ASSOCIATED WITH UPPER TROUGH BEGINS
TO OVERSPREAD DESTABILIZING AIR MASS. DESPITE THE MODEL VARIANCE
DISCUSSED IN SYNOPSIS...ALL DATA SETS SUGGEST THAT THE STRONGER DEEP
LAYER VERTICAL SHEAR WILL LAG SYSTEM WARM SECTOR TO THE W...WITH
MULTICELLS AND LINE SEGMENTS BEING THE PRIMARY CONVECTIVE MODES.
LOCALLY DAMAGING WIND GUSTS AND ISOLATED...SEVERE HAIL WILL
ACCOMPANY THE STRONGER STORMS...THOUGH THESE THREATS APPEARS TOO
MARGINAL TOO WARRANT INCLUSION OF HIGHER PROBABILITIES AND A
CATEGORICAL SLIGHT RISK.
.MEAD.. 10/06/2007
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