SWODY2
SPC AC 101738
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1238 PM CDT MON MAY 10 2010
VALID 111200Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE OH RIVER VALLEY...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTH-CENTRAL
PLAINS...
...SYNOPSIS...
WITHIN AN INCREASINGLY AMPLIFIED LARGE SCALE UPPER FLOW REGIME...THE
CURRENT PLAINS SHORTWAVE TROUGH IS EXPECTED TO DEAMPLIFY AS IT
CROSSES THE MIDWEST/GREAT LAKES REGION ON TUESDAY. MEANWHILE...A
SUBSEQUENT/STRONGER UPPER TROUGH WILL DIG INTO THE FOUR CORNERS
REGION THROUGH TUESDAY NIGHT.
IN ASSOCIATION WITH THE MIDWEST SHORTWAVE TROUGH...A SURFACE LOW
WILL GRADUALLY WEAKEN/TRANSITION EAST-NORTHEASTWARD ACROSS THE
MIDWEST/LOWER GREAT LAKES...WITH THE ASSOCIATED/TRAILING COLD FRONT
DECELERATING ACROSS THE OH RIVER VALLEY. THE WESTERN EXTENT OF THIS
FRONT WILL RETREAT NORTHWARD ACROSS THE SOUTH CENTRAL PLAINS/OZARKS
TUESDAY AFTERNOON/NIGHT AS LEE CYCLOGENESIS OCCURS ACROSS THE SOUTH
CENTRAL HIGH PLAINS.
...OH VALLEY...
STRONG WARM ADVECTION REGIME SHOULD BE DRIVING PLENTIFUL EARLY DAY
SHOWERS/TSTMS EARLY TUESDAY...WITH THIS ACTIVITY CONTINUING ACROSS
THE LOWER GREAT LAKES/UPPER OH VALLEY/CENTRAL APPALACHIANS DURING
THE AFTERNOON. IN THE WAKE OF THIS ACTIVITY...THE EXTENT/VIGOR OF
SURFACE BASED TSTM DEVELOPMENT ALONG/AHEAD OF THE COLD FRONT IS
SOMEWHAT QUESTIONABLE GIVEN THE WEAKENING NATURE OF THE PARENT
SHORTWAVE TROUGH AND A PRE-PEAK HEATING TREND TOWARD RISING UPPER
HEIGHTS ACROSS MUCH OF THE PRE-COLD FRONTAL WARM SECTOR.
NONETHELESS...A MODERATELY STRONG INSTABILITY FEED FROM THE
SOUTHWEST /1000-2000 J PER KG MLCAPE/ AND STRONG BUT LARGELY
UNIDIRECTIONAL WIND PROFILES WOULD SUPPORT SURFACE BASED STORMS
INCLUDING SOME SUPERCELLS/BOWING SEGMENTS. IN ALL...A CATEGORICAL
SLIGHT RISK APPEARS WARRANTED FOR THE POSSIBILITY OF DAMAGING
WINDS...AS WELL AS SEVERE HAIL AND PERHAPS A BRIEF TORNADO.
...CENTRAL/SOUTHERN PLAINS TO MO RIVER VALLEY/OZARKS...
STALLING FRONTAL BOUNDARY /PERHAPS AUGMENTED BY CONVECTIVE OUTFLOW/
SHOULD BEGIN TO RETREAT NORTH-NORTHWEST MAINLY ACROSS OK TUESDAY
AFTERNOON. WHILE AMPLE HEATING AND STEEP MID LEVEL LAPSE RATES
7.5-8.0 C/KM WILL CONTRIBUTE TO STRONG INSTABILITY EAST OF THE
DRYLINE/SOUTH OF THE RETREATING FRONTAL BOUNDARY...MODEST LARGE
SCALE SUPPORT/BOUNDARY LAYER CONVERGENCE IMPLY UNCERTAIN/LIMITED
TSTM COVERAGE. WITH THAT SAID...STRONG HEATING/MIXING ALONG THE
DRYLINE MAY BE SUFFICIENT TO HELP DEVELOP AT LEAST A FEW
STRONG/SEVERE TSTMS TUESDAY AFTERNOON/EARLY EVENING ACROSS
OK/PERHAPS ADJACENT NORTH TX. FURTHERMORE...THIS COULD BE AIDED BY
12Z GFS AND 00Z ECMWF IMPLICATIONS OF A SUBTLE SPEED
MAX/PERTURBATION CROSSING WEST/NORTHWEST TX TUESDAY AFTERNOON/EARLY
EVENING. GIVEN A RELATIVELY VOLATILE THERMODYNAMIC ENVIRONMENT AND
AMPLE VERTICAL SHEAR...AT LEAST A CONDITIONAL-TYPE SLIGHT RISK
ACROSS OK/ADJACENT NORTH TX APPEARS WARRANTED...AS LARGE
HAIL/ISOLATED TORNADOES WILL BE POSSIBLE PROVIDED SURFACE BASED TSTM
DEVELOPMENT TUESDAY LATE AFTERNOON/EVENING.
THE MORE LIKELY SCENARIO...HOWEVER...IS FOR A NOCTURNAL INCREASE IN
ELEVATED STORMS ACROSS FAR NORTHERN OK AND ESPECIALLY KS/MO TUESDAY
NIGHT OWING TO GRADUAL UPPER LEVEL HEIGHT FALLS AND A STRENGTHENING
LOW LEVEL JET. A SOURCE REGION RESERVOIR OF AMPLE
MOISTURE/INSTABILITY AND A FAVORABLY SHEARED ENVIRONMENT WILL
SUPPORT ELEVATED SUPERCELLS CAPABLE OF LARGE HAIL.
..GUYER.. 05/10/2010
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