SPC AC 041942

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   ISSUED BY 15TH OWS SCOTT AIR FORCE BASE IL
   0242 PM CDT THU JUN 04 2015

   VALID 042000Z - 051200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS OVER PARTS OF NERN CO...SRN
   NEB...NRN KS...SWRN IA...AND WRN MO...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE N CNTRL HIGH PLNS ESE
   INTO THE LWR MO VLY...

   ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE HIGH PLNS E INTO PARTS
   OF THE MID MS VLY...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF NV AND ID...

   ...SUMMARY...
   SCATTERED SEVERE THUNDERSTORMS WILL OCCUR FROM PARTS OF THE CENTRAL
   AND NORTHERN HIGH PLAINS...EAST-SOUTHEAST ACROSS THE CENTRAL PLAINS
   INTO THE LOWER MISSOURI VALLEY THIS AFTERNOON THROUGH TONIGHT.

   ...SYNOPTIC SETUP...
   MINIMAL CHANGE IN THE LARGE-SCALE PATTERN EXPECTED OVER THE LWR 48
   THROUGH FRI. CA LOW/TROUGH WILL BECOME INCREASINGLY REMOVED FROM THE
   MAIN BELT OF THE WLYS AS IT SETTLES FARTHER SSE ACROSS THAT
   STATE...WHILE RIDGE PERSISTS OVER THE SRN/CNTRL PLNS AND WEAK TROUGH
   PROGRESSES SLOWLY E ACROSS THE CAROLINAS. SEVERAL WEAK DISTURBANCES
   WILL ADVANCE ENE ACROSS THE CNTRL PLNS IN THE BAND OF FLOW TOPPING
   THE RIDGE...BUT HEIGHTS OVERALL WILL RISE ACROSS THAT REGION AS THE
   RIDGE AMPLIFIES AHEAD OF CA TROUGH.

   AT LWR LVLS...WEAK COLD FRONT ADVANCING SE ACROSS THE N CNTRL
   PLNS/UPR MS VLY WILL REINFORCE EXISTING FRONTAL ZONE/COMPOSITE
   OUTFLOW BOUNDARY EXTENDING FROM THE NRN/CNTRL HIGH PLNS ESE INTO NRN
   KS. THE REINFORCED BAROCLINIC ZONE WILL BE THE MAIN FOCUS FOR STRONG
   TO SVR STORMS THROUGH TNGT.

   ...CNTRL/NRN HIGH PLNS ESE INTO MID/LWR MO VLY TODAY/TNGT...
   ONGOING SLIGHTLY ELEVATED WAA TSTMS OVER ERN KS AND WRN MO SHOULD
   PERSIST THROUGH THE EVENING...WITH A DIMINISHING RISK FOR ISOLATED
   HAIL AND PERHAPS LOCALLY DMGG WIND. RESIDUAL OUTFLOW BOUNDARIES OVER
   THE LWR PLNS...AND LIGHT ELY UPSLOPE FLOW OVER THE HIGH
   PLNS...SHOULD SUPPORT NEW STORM DEVELOPMENT OVER THE CNTRL PLNS
   REGION WITH SFC HEATING LATE THIS AFTN.

   MOISTURE OVER THE REGION HAS SOMEWHAT INCREASED RELATIVE TO RECENT
   DAYS...ESPECIALLY OVER ERN TWO-THIRDS OF SLIGHT RISK AREA WHERE PW
   WILL REMAIN AOA 1.50 INCHES OVER NE KS/ERN NEB. COUPLED WITH
   CONTINUING PRESENCE OF DEEP EML...THIS SHOULD YIELD VERY STRONG
   INSTABILITY BY MID-LATE AFTN...WITH DEW POINTS IN THE UPPER 60S TO
   LOW 70S...MLCAPE AOA 3000 J/KG...AND SBCAPE AOA 3500 J/KG OVER N
   CNTRL KS AND MUCH OF SRN NEB AWAY FROM CONVECTIVE DEBRIS. MLCAPE
   ABOVE 2000 J/KG SHOULD EXTEND W INTO PARTS OF THE NEB PANHANDLE AND
   NE CO.

   WHILE DEEP WLY SHEAR WILL BE COMPARATIVELY MODEST /AROUND 30
   KTS/...IT WILL BE SUFFICIENT FOR SUSTAINED STORMS/SUPERCELLS GIVEN
   DEGREE OF BUOYANCY. THESE WILL BE CAPABLE OF VERY LARGE
   HAIL...LOCALLY DMGG WIND...AND A COUPLE OF TORNADOES. THE LATTER
   THREAT SHOULD BE GREATEST INVOF ENHANCED LOW-LVL MOIST/BACKED FLOW
   INVOF MESOSCALE BOUNDARY SEGMENTS...AND IN UPSLOPE REGION OVER NE
   CO/SW NEB/NW KS. FARTHER SW...ISOLD LATE DAY TSTMS WITH LARGE HAIL
   AND POSSIBLY A TORNADO ARE EXPECTED ALONG LEE TROUGH/DRY LINE
   EXTENDING SSW FROM WRN KS INTO W TX/FAR ERN NM. WITH THIS OUTLOOK...
   SLIGHT RISK HAS BEEN EXPANDED SWWD INTO THE NRN TX PANHANDLE FOR
   THESE THREATS. 

   BY EVE...EXPECT THE NRN KS/SRN NEB STORMS TO MERGE INTO ONE OR TWO
   SIZABLE CONVECTIVE SYSTEMS. THESE SHOULD MOVE/DEVELOP ESE INTO SW IA
   AND NRN MO LATER TNGT...WITH EMBEDDED FORWARD-PROPAGATING/POSSIBLE
   BOWING SEGMENTS POSING A RISK FOR LOCALLY DMGG WIND AND HAIL THROUGH
   EARLY FRI. AN ADDITIONAL AREA OR TWO OF MORE ELEVATED STORMS COULD
   ARISE OVER NE NEB THIS EVE AND MOVE/DEVELOP ESE INTO NW AND CNTRL IA
   WITH A RISK FOR SVR WIND/HAIL GIVEN EXPECTED INSTABILITY IN THE
   REGION. FOR THIS REASON THE SLIGHT AND ENHANCED RISK AREAS WERE
   EXPANDED NWD SOME. 

   ...CNTRL/NRN NV THIS AFTN/EVE...
   WDLY SCTD RELATIVELY HIGH-BASED DIURNAL STORMS WITH A RISK FOR
   LOCALLY DMGG WIND AND MARGINALLY SVR HAIL COULD ARISE IN
   STRENGTHENING/DEEPENING SSW FLOW DOWNSTREAM FROM CA UPR LOW.

   ..15_OWS.. 06/04/2015

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