Monday, August 19, 2013

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 190555
SWODY2
SPC AC 190553

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT MON AUG 19 2013

VALID 201200Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
PROGRESSIVE WLY FLOW REGIME WILL RESIDE OVER FAR NRN PORTIONS OF THE
CONUS INTO CANADA ON TUESDAY. S OF THESE AREAS...AN UPPER TROUGH
WILL MOVE VERY LITTLE OVER THE MIDWEST...A RIDGE WILL BE CENTERED
OVER THE SRN ROCKIES...AND AN UPPER LOW WILL LINGER OFFSHORE FROM
CNTRL CA. AT THE SURFACE...A LEE TROUGH WILL INITIALLY BE POSITIONED
FROM ND SWWD INTO THE CNTRL HIGH PLAINS. HOWEVER...AS A SHORTWAVE
TROUGH MOVES E ACROSS THE CANADIAN PRAIRIE PROVINCES DURING THE
NIGHT...A COLD FRONT WILL ADVANCE SWD INTO THE DAKOTAS AND NRN MN.

...NRN HIGH PLAINS INTO NRN MN...
SURFACE TROUGH IS FORECAST TO RESIDE FROM NRN ND SWWD INTO THE CNTRL
HIGH PLAINS DURING TUESDAY AFTERNOON. LOW-LEVEL SLYS E OF THIS
FEATURE WILL ESTABLISH SURFACE DEWPOINTS IN THE 60S...WHILE ALONG
AND TO ITS W...DEWPOINTS WILL BE IN THE 40S AND 50S. PLUME OF STEEP
MIDLEVEL LAPSE RATES LOCATED ABOVE THE MOIST LAYER COMBINED WITH
STRONG DAYTIME HEATING WILL YIELD MLCAPE VALUES FROM 1000-2000
J/KG...WHICH WILL SUPPORT ISOLATED THUNDERSTORM DEVELOPMENT INVOF
THE SURFACE TROUGH DURING THE AFTERNOON. COVERAGE MAY INCREASE
FURTHER DURING THE EVENING/NIGHT AS A COLD FRONT MOVES SWD INTO THE
NRN PLAINS AND ENCOUNTERS A STRENGTHENING SSWLY LOW-LEVEL JET.
DEEP-LAYER VERTICAL WIND SHEAR WILL NOT BE PARTICULARLY STRONG
ACROSS THE REGION /AOB 35 KT/...BUT THE STEEP LAPSE RATE/MODERATE
CAPE ENVIRONMENT WILL FAVOR A FEW INSTANCES OF LARGE HAIL AND
DAMAGING WIND GUSTS.

...NRN/CNTRL SIERRA NEVADA MOUNTAINS...
DEVELOPMENT OF STEEP LAPSE RATES DURING THE AFTERNOON COMBINED WITH
MODEST LOW-LEVEL MOISTURE /DEWPOINTS POSSIBLY IN THE 40S/ WILL AID
IN MUCAPE VALUES RANGING FROM 500-1000 J/KG OVER PORTIONS OF THE
NRN/CNTRL SIERRA NEVADA MOUNTAINS. LARGE-SCALE ASCENT ASSOCIATED
WITH A CLOSED LOW NEAR THE CNTRL CA COAST WILL SPREAD ACROSS THE
AREA AND AID IN ISOLATED TO SCATTERED THUNDERSTORMS DURING THE
AFTERNOON/EVENING. IN ADDITION...SSELY WINDS IN THE MID/UPPER-LEVELS
OF THE ATMOSPHERE ARE FORECAST TO STRENGTHEN TO 30-50 KT...WHICH MAY
BE SUFFICIENT FOR MARGINAL STORM ORGANIZATION. THIS ENVIRONMENT
COULD SUPPORT A COUPLE OF STRONG STORMS POSING A RISK FOR HAIL/WIND
GUSTS NEAR SEVERE LEVELS.

..GARNER.. 08/19/2013

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