SPC 1300Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0740 AM CDT THU JUN 27 2013 VALID 271300Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CENTRAL PLAINS INTO AR.... ...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE EASTERN UNITED STATES... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE WESTERN GREAT LAKES... A BROAD RIDGE IS PRESENT THIS MORNING OVER THE SOUTHWEST STATES...WHILE NORTHWEST FLOW ALOFT BECOMES DOMINANT OVER THE PLAINS/MS VALLEY/OH VALLEY/SOUTHEAST. SEVERAL AREAS ARE FORECAST TO SEE THE POTENTIAL FOR STRONG TO SEVERE STORMS LATER THIS AFTERNOON AND EVENING. ...NEB/KS/WRN MO/OK/AR... A CLUSTER OF DISCRETE THUNDERSTORMS IS ONGOING THIS MORNING OVER EASTERN NEB. THESE STORMS FORMED A FEW HOURS AGO AHEAD OF A WEAK SHORTWAVE TROUGH TOPPING THE RIDGE...AND IN A REGIME OF RATHER STRONG LOW LEVEL WARM ADVECTION. THESE STORMS WILL LIKELY PERSIST THROUGH MUCH OF THE MORNING AND SPREAD INTO PARTS OF MO/KS. FORECAST SOUNDINGS AT DDC/TOP/SGF SHOW STEEP MID LEVEL LAPSE RATES AND SUFFICIENT DEEP LAYER SHEAR CAPABLE OF ISOLATED SEVERE WEATHER. BY LATE AFTERNOON...TEMPERATURES ACROSS MUCH OF KS WILL EXCEED 100F...WHICH SHOULD BE SUFFICIENT TO REACH CONVECTIVE TEMPERATURE AND YIELD ADDITIONAL SCATTERED THUNDERSTORMS. A DEEPLY MIXED BOUNDARY LAYER AND INCREASING NORTHERLY FLOW ALOFT SUGGEST THAT STORMS WILL POSE A RISK OF DAMAGING WIND GUSTS AND HAIL. SEVERE THREAT IS EXPECTED TO SAG INTO AT LEAST NORTHERN OK/NORTHWEST AR BEFORE WEAKENING THIS EVENING. ...EASTERN STATES... HAVE OPTED TO EXPAND SLGT RISK AREA OVER THE EASTERN U.S. FOR TODAY. AREAS OF STRONG HEATING WILL EXIST FROM SOUTHEAST NY INTO MUCH OF SC/GA/AL TODAY. THIS HEATING WILL HELP TO INITIATE ISOLATED STRONG/SEVERE STORMS. MODERATE CAPE WILL BE PERVASIVE IN THIS REGION...ALONG WITH CYCLONIC FLOW ALOFT AND VARIOUS REMNANT OUTFLOW BOUNDARIES. WHILE THE SPECIFIC DETAILS OF WHERE/WHEN STORMS WILL FORM IS UNCERTAIN...IT APPEARS LIKELY THAT AT LEAST ISOLATED THUNDERSTORMS WILL FORM ALONG THIS CORRIDOR. DAMAGING WINDS ARE PROBABLY THE MAIN THREAT...BUT LARGE HAIL WILL ALSO BE POSSIBLE IN THE STRONGEST CORES. ...WI INTO IL/IND... A BELT OF NWLY FLOW ALOFT AND MID-LEVEL HEIGHT FALLS ASSOCIATED WITHIN AN AMPLIFYING UPPER TROUGH ARE EXPECTED TO AFFECT THE WESTERN GREAT LAKES REGION TODAY. THE ATMOSPHERE WILL LIKELY BECOME MODERATELY UNSTABLE AND WEAKLY CAPPED AS DIABATIC WARMING COMMENCES. WIDELY SCATTERED STORMS SHOULD DEVELOP BY AFTERNOON WITH UNIDIRECTIONAL NWLY SHEAR SUPPORTIVE OF A FEW SUPERCELLS AND STORM SPLITS WITH ISOLATED LARGE HAIL AND A FEW STRONG WIND GUSTS THE MAIN THREATS. ..HART/ROGERS.. 06/27/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1300.html
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