Monday, November 9, 2009

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 091728
SWODY2
SPC AC 091727

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1127 AM CST MON NOV 09 2009

VALID 101200Z - 111200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A COUPLE OF PERTURBATIONS...NOW EMBEDDED WITHIN A LARGER SCALE
TROUGH OFF THE BRITISH COLUMBIA/PACIFIC NORTHWEST COAST...ARE
FORECAST TO PROGRESS INLAND ACROSS THE CANADIAN ROCKIES/NORTHERN
U.S. INTERMOUNTAIN REGION LATER TODAY AND TONIGHT. MODELS SUGGEST
THAT THESE FEATURES WILL CONTINUE EASTWARD ACROSS THE CANADIAN
PRAIRIES TUESDAY...AS UPSTREAM IMPULSES CONTRIBUTE TO SHARPENING
TROUGHING WEST OF THE PACIFIC COAST. IN RESPONSE....DOWNSTREAM
RIDGING APPEARS LIKELY TO SHIFT EASTWARD THROUGH THE UPPER
MISSISSIPPI VALLEY/GREAT LAKES REGION...AND ACROSS THE
CENTRAL/SOUTHERN PLAINS. SOME AMPLIFICATION OF THIS RIDGING MAY
OCCUR...WITH A SIGNIFICANT SHORT WAVE TROUGH DIGGING DOWNSTREAM
ACROSS THE GREAT LAKES AND OHIO VALLEY. GUIDANCE IS SUGGESTIVE THAT
THIS LATTER FEATURE MAY GRADUALLY CONSOLIDATE WITH TROUGHING IN A
WEAKER BRANCH OF WESTERLIES ALONG THE GULF COAST...AND THE REMNANTS
OF IDA...AS CURRENT PROMINENT UPPER RIDGE OVER PARTS OF THE
SOUTHEAST AND WESTERN ATLANTIC SLOWLY BREAKS DOWN.

...EASTERN GULF COAST...
WHILE MID-LEVEL REMNANTS OF THE INCREASINGLY SHEARED IDA APPEAR
LIKELY TO MIGRATE INLAND OF GULF COASTAL AREAS...UNCERTAINTY REMAINS
HIGHER CONCERNING THE TRACK OF THE SURFACE LOW. GUIDANCE GENERALLY
INDICATES THAT THIS FEATURE WILL APPROACH THE MOBILE BAY AREA BY 12Z
TUESDAY...BEFORE TURNING EASTWARD ALONG A WEAK LOW-LEVEL BAROCLINIC
ZONE NOW PRESENT NEAR THE COAST. WHILE THIS WILL PROBABLY BE
ACCOMPANIED BY STRENGTHENING LOW-LEVEL FLOW FIELDS AND THE EVOLUTION
OF LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS SUPPORTIVE OF TORNADO
OR DAMAGING WIND POTENTIAL IN CONVECTION...WEAK TO NEGLIGIBLE
BOUNDARY LAYER BASED INSTABILITY STILL SEEMS LIKELY TO BE A LIMITING
FACTOR WITH REGARD TO THE SEVERE THREAT. INLAND ADVECTION OF
LOWER/MID 70S SURFACE DEW POINTS CURRENTLY APPEARS A VERY LOW
PROBABILITY...AND...UNLESS THIS OCCURS...EVEN THUNDERSTORM
PROBABILITIES SEEM NEGLIGIBLE. HOWEVER...IT IS POSSIBLE THAT WEAK
MID-LEVEL COOLING ASSOCIATED WITH THE WEAK SOUTHERN BRANCH TROUGH
COULD BE ACCOMPANIED BY SUFFICIENT DESTABILIZATION FOR ISOLATED OR
WIDELY SCATTERED THUNDERSTORM ACTIVITY WEST OF THE REMNANT
CIRCULATION CENTER TUESDAY/TUESDAY NIGHT.

...PACIFIC NORTHWEST...
WEAK DESTABILIZATION ASSOCIATED WITH MODEST ONSHORE FLOW BENEATH A
COLD MID-LEVEL ENVIRONMENT MAY SUPPORT A FEW THUNDERSTORMS
TUESDAY...ESPECIALLY NEAR COASTAL AREAS.

..KERR.. 11/09/2009

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