SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1220 PM CDT TUE AUG 06 2013 VALID 071200Z - 081200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF SRN KS...NRN OK...AND THE NRN TX PANHANDLE... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE OH VALLEY AND SRN GREAT LAKES... ...SYNOPSIS... LITTLE MOVEMENT OF AN UPPER LOW OVER MANITOBA/ONTARIO IS EXPECTED ON WEDNESDAY AS A SERIES OF DISTURBANCES ROTATE THROUGH THE BASE OF THE LARGER SCALE TROUGH OVER THE UPPER MIDWEST/GREAT LAKES REGIONS. TO THE WEST AND NORTH OF A SUPPRESSED UPPER RIDGE CENTERED OVER THE SERN U.S....A MID-LEVEL LOW INITIALLY OVER NWRN MEXICO ON TUESDAY WILL SLOWLY MOVE NEWD FROM THE FOUR CORNERS TO THE CNTRL HIGH PLAINS AND WEAKEN DURING THE PERIOD. A COLD FRONT WILL MOVE SEWD THROUGH THE GREAT LAKES WITH THE TRAILING WRN PORTION OF THE FRONT DECELERATING INTO NRN OK/NRN TX PANHANDLE AS A SURFACE LOW DEVELOPS OVER THE WRN OK/TX PANHANDLE VICINITY BY TUESDAY EVENING. A LEE TROUGH SHOULD PERSIST ACROSS WRN TX. ...PORTIONS OF THE CNTRL-SRN PLAINS STATES... WIDESPREAD CLOUD COVER AND A WEAKENING STORM CLUSTER OR TWO IS EXPECTED TO BE ONGOING WEDNESDAY MORNING NEAR/NORTH OF THE FRONT OVER SRN KS INTO SWRN MO. DIFFERENTIAL HEATING OWING TO STRONG INSOLATION AND TEMPS RISING AOA 100 DEG F S OF THE BOUNDARY OVER OK/TX WILL STRENGTHEN THE THERMAL GRADIENT DURING THE DAY. ENELY POST-FRONTAL WINDS AND MOIST LOW LEVELS /CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S TO LOWER 70S/ BENEATH MODESTLY STEEP H7-H5 LAPSE RATES /7-7.5 DEG C PER KM/...WILL CONTRIBUTE TO A MODERATE TO VERY UNSTABLE AIRMASS WITH 2000-3000 J/KG MLCAPE NORTH OF THE FRONT BY MID AFTERNOON. A CAP SHOULD INHIBIT SFC-BASED DEVELOPMENT UNTIL THE MID-LATE AFTERNOON WITH STORMS PREFERENTIALLY INITIATING IN VICINITY OF THE STALLED FRONT AS WELL AS NEAR THE HIGHER TERRAIN OF SERN CO/NERN NM WITHIN THE MOIST UPSLOPE REGIME. DESPITE ONLY MODEST WSWLY MID-LEVEL FLOW /20-30 KT/...STRONGLY VEERING WIND PROFILES N OF THE FRONT WILL YIELD 25-40 KT EFFECTIVE SHEAR --SUFFICIENT FOR STORM ORGANIZATION. THE THREAT FOR ISOLD LARGE HAIL/SEVERE WIND GUSTS WILL ACCOMPANY THE STRONGER STORMS AS STORM COVERAGE INCREASES DURING THE EARLY EVENING. INCREASED ASCENT PROVIDED BY THE NOCTURNALLY-AIDED STRENGTHENING OF THE LLJ OVER OK/TX DURING THE MID-LATE EVENING WILL LIKELY SERVE TO PROMOTE UPSCALE GROWTH OVER KS/OK AFTER DARK...WITH ISOLD SEVERE WIND GUSTS BECOMING THE MAIN THREAT. ...LOWER GREAT LAKES THRU THE OH VALLEY AND MID MS RIVER VALLEY... A RESERVOIR OF MID 60S TO LOWER 70S DEWPOINTS OVER THE LOWER OH VALLEY TUESDAY WILL BE DRAWN NEWD INTO THE SRN GREAT LAKES AHEAD OF THE APPROACHING FRONT ON WEDNESDAY. ALTHOUGH IT IS UNCERTAIN AT THIS TIME WHERE THE GREATEST HEATING WILL OCCUR DUE TO EXPECTED STORMS AND THEIR OUTFLOWS MODULATING SURFACE CONDITIONS PRIOR TO WEDNESDAY AFTERNOON...IT APPEARS MODERATE INSTABILITY WILL DEVELOP WITHIN A CORRIDOR FROM LAKE ERIE SWWD INTO THE MID MS RIVER VALLEY. THE BELT OF STRONGER H5 FLOW IS FORECAST REMAIN GENERALLY OVER THE SRN GREAT LAKES AND AREAS NORTHWARD...IN CLOSER PROXIMITY TO THE EMBEDDED FEATURES MOVING THROUGH THE FLOW OVER THE UPPER GREAT LAKES...FAVORING A MULTICELLULAR MODE. THE MORE INTENSE STORMS WILL POTENTIALLY BE CAPABLE OF SPORADIC POCKETS OF WIND DAMAGE AND MARGINALLY SEVERE HAIL DURING THE AFTERNOON WITH THE STORMS SUBSEQUENTLY WEAKENING DURING THE EVENING. ...TN VALLEY... DAYTIME HEATING WITHIN A MOISTURE RICH/WEAKLY CAPPED BOUNDARY LAYER WILL LIKELY PROMOTE SCATTERED STORMS DEVELOPING BY THE EARLY AFTERNOON ACROSS THE TN VALLEY. PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES AND GENERALLY WEAK VEERING FLOW WILL SUPPORT MULTICELLS CAPABLE OF ISOLD WET MICROBURSTS AND THE POSSIBILITY OF LOCALIZED WIND DAMAGE. ..SMITH/KERR.. 08/06/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_1730.html
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