Aug 30, 2014 1300 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   0750 AM CDT SAT AUG 30 2014

   VALID 301300Z - 311200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON/EVENING
   ACROSS THE NRN HIGH PLAINS...

   ...SUMMARY...
   A FEW SEVERE STORMS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING
   ACROSS PARTS OF THE NORTHERN HIGH PLAINS.  OTHER STRONG STORMS ARE
   POSSIBLE TODAY IN A CORRIDOR ARCING FROM THE CENTRAL GULF COAST INTO
   THE TENNESSEE VALLEY...AND ACROSS LOWER MICHIGAN AND ADJACENT
   PORTIONS OF THE GREAT LAKES REGION.

   ...NRN ROCKIES TO NRN HIGH PLAINS THIS AFTERNOON INTO TONIGHT...
   A MIDLEVEL TROUGH AND ASSOCIATED BELT OF 35-50 KT FLOW WILL PROGRESS
   EWD OVER THE NRN GREAT BASIN/ROCKIES TO THE NRN HIGH PLAINS BY
   TONIGHT.  AN ACCOMPANYING COLD FRONT WILL MOVE ACROSS WY/MT THIS
   AFTERNOON/EVENING...AS LEE CYCLOGENESIS IN NE WY DRAWS A NARROW
   CORRIDOR OF RESIDUAL BOUNDARY LAYER MOISTURE NWWD INTO THE NRN HIGH
   PLAINS.  INITIAL CONVECTION WILL FORM WITHIN THE BAND OF ASCENT
   PRECEDING THE MIDLEVEL WAVE...AND STORMS SHOULD STRENGTHEN LATE THIS
   AFTERNOON/EVENING WHILE ENCOUNTERING THE RICHER MOISTURE ON THE HIGH
   PLAINS E/NE OF THE BIG HORNS.

   SURFACE HEATING/MIXING NEAR THE LEE CYCLONE AND ALONG THE COLD FRONT
   WILL REDUCE CONVECTIVE INHIBITION...WHILE MIDLEVEL LAPSE RATES
   GREATER THAN 7 C/KM AND BOUNDARY LAYER DEWPOINTS IN THE 50S RESULT
   IN MLCAPE UP TO 1500 J/KG.  IN COMBINATION WITH INCREASING VERTICAL
   SHEAR...THE THERMODYNAMIC PROFILES WILL SUPPORT ORGANIZED
   CLUSTERS/SUPERCELLS WITH AN ATTENDANT RISK FOR DAMAGING WINDS AND
   LARGE HAIL BEFORE CONVECTION WEAKENS TONIGHT IN THE CENTRAL DAKOTAS
   WHERE BUOYANCY WILL BE WEAKER.  

   ...LOWER MI/NRN INDIANA THIS AFTERNOON...
   A MIDLEVEL TROUGH OVER NW IL/SW WI...AND AN ASSOCIATED SURFACE LOW
   IN CENTRAL WI...WILL MOVE ENEWD TO NRN LOWER MI BY THIS EVENING. 
   LOW-LEVEL CONVERGENCE/ASCENT WILL BE FOCUSED NEAR THE LOW AND A
   TRAILING WEAK COLD FRONT AS DAYTIME HEATING REMOVES CONVECTIVE
   INHIBITION AND 68-70 F DEWPOINTS SPREAD NEWD INTO LOWER MI. 
   SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG THE WIND SHIFT
   THIS AFTERNOON...WHEN ORGANIZED CLUSTERS/MARGINAL SUPERCELLS COULD
   PRODUCE ISOLATED DAMAGING GUSTS GIVEN MODERATE BUOYANCY...EFFECTIVE
   BULK SHEAR NEAR 35 KT...AND A BELT OF 40 KT FLOW IN THE 850-500 MB
   LAYER FOR POTENTIAL DOWNWARD MOMENTUM TRANSFER IN HEAVY
   PRECIPITATION CORES.  POOR MIDLEVEL LAPSE RATES WILL TEND TO LIMIT
   UPDRAFT STRENGTH AND ANY HAIL RISK...THOUGH LOWER MI WILL BE
   MONITORED CLOSELY FOR THE POSSIBILITY OF A LOW-END SLIGHT RISK IN
   LATER OUTLOOK UPDATES.

   ...LA AREA TODAY...
   A PLUME OF TROPICAL MOISTURE /PW VALUES AOA 2.25 INCHES AND LOW-MID
   70S DEWPOINTS/ HAS SPREAD INLAND FROM THE NW GULF TO LA IN
   ASSOCIATION WITH A WEAK MIDLEVEL TROUGH NEAR THE SABINE RIVER. THE
   MOIST ENVIRONMENT IS SUPPORTING SCATTERED THUNDERSTORMS THIS
   MORNING...WHILE A BELT OF 30-35 KT SLY FLOW NEAR 850 MB IS
   CONTRIBUTING TO SOME ENHANCEMENT OF LOW-LEVEL SHEAR /EFFECTIVE SRH
   OF 150-250 M2 PER S2/.  THIS ENVIRONMENT IS SUPPORTIVE OF SOME
   WEAKLY ROTATING STORMS AND THE RISK FOR A BRIEF TORNADO AND/OR
   DAMAGING GUST FROM THIS MORNING INTO EARLY AFTERNOON AS THE SYSTEM
   MOVES NNEWD.

   ..THOMPSON/MOSIER.. 08/30/2014