SWODY3
SPC AC 080822
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0222 AM CST MON NOV 08 2010
VALID 101200Z - 111200Z
...SYNOPSIS...
MODELS INDICATE THAT SHORT WAVE RIDGING WILL SHIFT EASTWARD INTO THE
PACIFIC COAST AND CANADIAN ROCKIES DURING THIS FORECAST
PERIOD...AHEAD OF A PROGRESSIVE SPLITTING SHORT WAVE TROUGH ACROSS
THE NORTHEAST PACIFIC. AS THIS OCCURS...AND DOWNSTREAM BLOCKING
PERSISTS...A SIGNIFICANT IMPULSE WITHIN BROADER SCALE TROUGHING OVER
THE REMAINDER OF THE WESTERN AND CENTRAL U.S. IS PROGGED TO LIFT
NORTHWARD FROM THE PLAINS THROUGH THE CENTRAL CANADIAN/U.S. BORDER
AREA...AS ANOTHER IMPULSE DIGS ACROSS THE GREAT BASIN AND FOUR
CORNERS STATES. IN CONJUNCTION WITH THESE DEVELOPMENTS...A MODEST
SURFACE CYCLONE APPEARS LIKELY TO MIGRATE NORTH OF THE INTERNATIONAL
BORDER...WITH A TRAILING COLD FRONT ADVANCING EASTWARD THROUGH THE
UPPER MISSISSIPPI VALLEY...WHILE STALLING...THEN PERHAPS
RETREATING...WITH THE FORMATION OF A ANOTHER SURFACE WAVE ACROSS THE
SOUTH CENTRAL HIGH PLAINS BY LATE WEDNESDAY NIGHT.
IN ASSOCIATION WITH THIS REGIME...LARGE-SCALE FORCING FOR UPWARD
VERTICAL MOTION WILL PROBABLY SUPPORT A RELATIVE INCREASE IN
CONVECTIVE POTENTIAL ACROSS PARTS OF THE PLAINS AND MISSISSIPPI
VALLEY WEDNESDAY AND WEDNESDAY NIGHT. THE EVOLUTION OF ONE OR TWO
MARGINAL SEVERE EVENTS DOES NOT APPEAR INCONCEIVABLE.
HOWEVER...MOISTURE INFLUX OFF THE GULF OF MEXICO IS LIKELY TO REMAIN
RATHER WEAK...WHICH WILL CONTINUE TO MINIMIZE POTENTIAL FOR
DESTABILIZATION.
...UPPER MISSISSIPPI VALLEY...
NAM FORECAST SOUNDINGS SUGGEST SUFFICIENT MOISTENING IN A NARROW
PRE-FRONTAL TONGUE ACROSS PARTS OF EASTERN IOWA/MINNESOTA AND
WESTERN WISCONSIN BY WEDNESDAY AFTERNOON FOR THE DEVELOPMENT OF
MIXED LAYER CAPE AROUND 100 TO 250 J/KG. THIS MAY BE SUFFICIENT TO
SUPPORT SCATTERED THUNDERSTORMS...PERHAPS A NARROW BROKEN LINE
...NEAR OR JUST AHEAD OF THE FRONT DURING THE LATE AFTERNOON OR
EVENING HOURS. WHILE VERTICAL SHEAR IS PROGGED TO BE STRONG...
INCLUDING FAIRLY SIZABLE LOW-LEVEL HODOGRAPHS...THE MAGNITUDE OF THE
WIND FIELDS AND SHEAR ARE NOT LIKELY TO BE PARTICULARLY STRONG FOR
THE TIME OF YEAR. GIVEN THE THERMODYNAMIC PROFILES...ISOLATED
TORNADOES OR LOCALIZED STRONG GUSTS APPEAR MORE PROBABLE THAN
WIDESPREAD DAMAGING WINDS. AND THIS POTENTIAL APPEARS TOO LOW FOR
EVEN 5 PERCENT PROBABILITIES AT THE PRESENT TIME.
...SOUTH CENTRAL PLAINS INTO OZARKS/LWR MO VALLEY...
STRENGTHENING LOWER/MID TROPOSPHERIC WARM ADVECTION MAY CONTRIBUTE
TO SUFFICIENT LIFT AND DESTABILIZATION FOR INCREASING THUNDERSTORM
ACTIVITY FROM PARTS OF WESTERN/NORTHERN OKLAHOMA THROUGH SOUTHERN
KANSAS AND PARTS OF SOUTHERN/CENTRAL MISSOURI. THE THREAT FOR HAIL
MAY NOT BE COMPLETELY NEGLIGIBLE...BUT APPEARS TOO LOW FOR 5 PERCENT
PROBABILITIES AT THE PRESENT TIME.
..KERR.. 11/08/2010
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