Sep 9, 2014 0600 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   1249 AM CDT TUE SEP 09 2014

   VALID 091200Z - 101200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL
   PLAINS...MID MO VALLEY AND MID TO UPPER MS VALLEY...

   ...SUMMARY...
   SEVERE STORMS ARE EXPECTED LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT
   ACROSS PARTS OF THE CENTRAL PLAINS AND MID MISSOURI VALLEY
   NORTHEASTWARD INTO THE UPPER MIDWEST.  THESE STORMS WILL BE
   ACCOMPANIED BY DAMAGING WIND GUSTS...A FEW TORNADOES...AND PERHAPS
   LARGE HAIL.

   ...CNTRL PLAINS/MID MO VALLEY/UPPER MIDWEST...
   AN UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE INTERMOUNTAIN WEST
   TODAY AS A SUBTLE LEAD SHORTWAVE TROUGH MOVES INTO THE MID MO
   VALLEY. AT THE SFC...A LOW WILL DEEPEN ACROSS WRN KS TODAY AS A COLD
   FRONT ADVANCES SWD INTO THE CNTRL PLAINS. AHEAD OF THE FRONT...SFC
   DEWPOINTS SHOULD BE IN THE UPPER 60S TO NEAR 70 F FROM KS AND ERN
   NEB EWD ACROSS IA AND MO. THIS WILL ALLOW MODERATE INSTABILITY TO
   DEVELOP BY AFTERNOON ACROSS A LARGE AREA OF THE CNTRL PLAINS AND
   UPPER MIDWEST. BY EARLY TO MID AFTERNOON...THUNDERSTORM INITIATION
   APPEARS LIKELY TO TAKE PLACE ACROSS SRN NEB AND NRN KS WHERE THE SFC
   LOW AND APPROACHING COLD FRONT SHOULD RESULT IN ENHANCED LOW-LEVEL
   CONVERGENCE. STORM COVERAGE SHOULD GRADUALLY INCREASE ACROSS THE ERN
   HALF OF NEB AND NRN KS DURING THE LATE AFTERNOON AS A 35 TO 45 KT
   LOW-LEVEL JET STRENGTHENS ACROSS THE CNTRL PLAINS. OTHER STORMS MAY
   INITIATE IN THE MID MO VALLEY AS THE NOSE OF THE LOW-LEVEL JET MOVES
   ACROSS THAT AREA. A MARKETED INCREASE IN STORM COVERAGE DURING THE
   LATE AFTERNOON AND EARLY EVENING SHOULD AID MCS DEVELOPMENT WITH A
   LARGE CLUSTER OF STORMS MOVING EWD INTO IA AND NWRN MO BY EARLY
   EVENING.

   FORECAST SOUNDINGS AT 00Z/WEDNESDAY FOR LINCOLN AND OMAHA NEB SHOW A
   VERY MOIST BOUNDARY LAYER WITH MLCAPE IN THE 1500 TO 2000 J/KG
   RANGE. IN ADDITION...WINDS VEER WITH HEIGHT IN THE 850 TO 500 MB
   LAYER WITH 0-6 KM SHEAR AROUND 40 KT. THIS SHOULD BE FAVORABLE FOR
   SUPERCELL DEVELOPMENT DURING THE FIRST FEW HOURS OF THE EVENT. A FEW
   TORNADOES AND ISOLATED LARGE HAIL WILL BE POSSIBLE WITH THE MORE
   DOMINANT SUPERCELLS. THE CURRENT THINKING IS THAT INCREASING STORM
   COVERAGE AND CELL MERGERS WILL FAVOR THE DEVELOPMENT OF A LINEAR MCS
   BY EARLY THIS EVENING. THIS SCENARIO WOULD INCREASE THE POTENTIAL
   FOR WIND DAMAGE ESPECIALLY IF A COLD POOL CAN ORGANIZE. AN ENHANCED
   WIND-DAMAGE THREAT MAY OCCUR ACROSS THE OMAHA AND DES MOINES
   VICINITIES. THE SEVERE THREAT COULD PERSIST INTO THE OVERNIGHT
   PERIOD AS FAR EAST AS IL DEPENDING UPON HOW LONG THE MCS CAN
   PERSIST.

   ...UPPER MS VALLEY/WRN GREAT LAKES REGION...
   AN UPPER-LEVEL TROUGH WILL MOVE ACROSS THE INTERMOUNTAIN WEST TODAY
   AS A LEAD SHORTWAVE TROUGH MOVES NEWD ACROSS THE MID MO VALLEY. AT
   THE SFC...A COLD FRONT WILL MOVE SWD ACROSS ERN PARTS OF THE NRN
   PLAINS AND INTO UPPER MS VALLEY THIS AFTERNOON. SOUTH OF THE
   FRONT...SFC DEWPOINTS WILL BE IN THE 60S F FROM SE SD AND IA NEWD
   INTO SRN MN AND WI. THIS SHOULD ALLOW FOR THE DEVELOPMENT OF
   MODERATE INSTABILITY BY AFTERNOON ACROSS MUCH OF THE MULTI-STATE
   REGION. THUNDERSTORMS SHOULD FIRST DEVELOP IN THE MID MO VALLEY WITH
   CONVECTION INCREASING IN COVERAGE AND MOVING NEWD INTO THE MID TO
   UPPER MS VALLEY DURING THE EARLY TO MID EVENING.

   FORECAST SOUNDINGS AT 03Z/WEDNESDAY FOR MINNEAPOLIS MN AND MADISON
   WI SHOW MODERATE INSTABILITY WITH MLCAPE IN THE 1500 TO 2000 J/KG
   RANGE. IN ADDITION...DIRECTIONAL AND SPEED SHEAR FROM THE LOW TO MID
   LEVELS WILL BE ENOUGH TO CREATE MODERATE DEEP-LAYER SHEAR. THIS
   SHOULD SUPPORT OF AN ISOLATED SEVERE THREAT BY EARLY EVENING AS
   CELLS INCREASE IN COVERAGE. DAMAGING WIND GUSTS AND HAIL WILL BE THE
   PRIMARY THREATS. HOWEVER...A MORE SUBSTANTIAL WIND-DAMAGE THREAT
   COULD DEVELOP IN ERN IA DURING THE MID TO LATE EVENING IF A COLD
   POOL CAN MOVE INTO THE REGION FROM THE SOUTHWEST.