Jul 23, 2014 0600 UTC Day 1 Convective Outlook

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1247 AM CDT WED JUL 23 2014

   VALID 231200Z - 241200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF MT...NRN
   ID...AND ERN WA...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN WY INTO WRN SD AND
   NWRN NEB...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN NY INTO ME...

   ...SUMMARY...
   SEVERE STORMS WITH MAINLY LARGE HAIL ARE LIKELY ACROSS NORTHERN
   MONTANA...IDAHO...AND EASTERN WASHINGTON WEDNESDAY AFTERNOON AND
   EVENING. LARGE HAIL IS ALSO LIKELY ACROSS THE BLACK HILLS
   REGION...WITH MARGINALLY SEVERE WINDS LIKELY FROM EASTERN NEW YORK
   INTO NEW ENGLAND DURING THE AFTERNOON.

   ...SYNOPSIS...
   A LARGE UPPER HIGH WILL REMAIN CENTERED OVER THE CNTRL ROCKIES...BUT
   WILL BEGIN TO FLATTEN AS A STRONG UPPER TROUGH MOVES FROM THE
   PACIFIC NW ACROSS MT. INCREASING COOLING AND WINDS ALOFT WILL RESULT
   IN SCATTERED THUNDERSTORMS FROM WA INTO MT AS LOW PRESSURE FORMS
   ACROSS THE NRN ROCKIES. ELY LOW-LEVEL WINDS WILL ALSO BRING MOISTURE
   WWD ACROSS ERN AND CNTRL MT...CREATING STRONG INSTABILITY FOR LARGE
   HAIL. 

   TO THE E...A LEE TROUGH WILL EXTEND SWD ACROSS THE NRN HIGH
   PLAINS...WITH ELY UPSLOPE FLOW ALSO RESULTING IN A FAVORED LARGE
   HAIL ZONE FROM ERN WY INTO WRN SD.

   TO THE E...A LOW PRESSURE TROUGH WILL DRIFT EWD ACROSS NEW
   ENGLAND...WITH MODEST SWLY FLOW ALOFT HELPING TO CREATE MARGINAL
   SHEAR FOR SCATTERED DAYTIME STORMS...SOME WITH STRONG WIND GUSTS. 

   ...NRN MT...NRN ID...ERN WA...
   A COLD FRONT WILL SURGE EWD ACROSS WA AND OREGON WITH LOW PRESSURE
   OVER ERN WA AT 21Z. DAYTIME HEATING AND STRONG COOLING ALOFT/FORCING
   FOR ASCENT WILL AID IN THE DEVELOPMENT OF SCATTERED STORMS. THESE
   STORMS WILL POSE A HAIL AND WIND THREAT...AND WILL SPREAD EWD ACROSS
   NRN ID AND INTO WRN MT.

   TO THE E...A SECONDARY AREA OF LOW PRESSURE IS EXPECTED OVER CNTRL
   MT...WITH DEEP ELY LOW-LEVEL FLOW BRINGING MID TO UPPER 50S F
   DEWPOINTS WELL WWD ACROSS MT. HEATING BENEATH COOLING PROFILES ALOFT
   WILL RESULT IN VERY STEEP LAPSE RATES...AND STRONG INSTABILITY. ELY
   FLOW VEERING TO WLY WITH HEIGHT WILL ALSO RESULT IN LONG HODOGRAPHS
   FAVORABLE FOR SUPERCELLS CAPABLE OF LARGE HAIL...PERHAPS VERY
   LARGE...ALONG WITH DAMAGING WINDS. A BRIEF TORNADO CANNOT BE RULED
   OUT ANYWHERE FROM ERN WA INTO MT AS WELL GIVEN EXPECTED STORM MODE.

   ...BLACK HILLS REGION...
   SELY UPSLOPE FLOW AS WELL AS HEATING WILL AGAIN INITIATE ISOLATED
   SEVERE STORMS BY LATE AFTERNOON. WINDS CHANGING DIRECTION WITH
   HEIGHT WILL MAXIMIZE HODOGRAPH LENGTH WITH COLD TEMPERATURES ALOFT
   FAVORING LARGE HAIL.

   OVERNIGHT...THE LOW-LEVEL JET WILL VEER TO SWLY...AND WILL ALLOW FOR
   A NEWD SURGE IN INSTABILITY. THIS MAY RESULT IN ISOLATED ELEVATED
   HAIL ACROSS THE DAKOTAS AND NERN NEB

   ...ERN NY INTO NEW ENGLAND...
   WLY FLOW ALOFT WILL INCREASE COINCIDENT WITH THE APPROACHING COLD
   FRONT...WITH DEEP-LAYER SHEAR UP TO AROUND 30 KTS AND PARALLEL TO
   THE BOUNDARY. HEATING AND MOISTURE ADVECTION WILL LEAD TO SUFFICIENT
   INSTABILITY FOR SCATTERED STRONG STORMS...WITH THE PRIMARY THREAT
   LOCALIZED SEVERE WIND GUSTS. SMALL HAIL IS LIKELY WITH SOME OF THE
   STORMS AS WELL. 

   ...AR...ERN OK...KY AND TN...
   SEVERAL MODELS INSIST THAT THERE WILL BE A CLUSTER OF THUNDERSTORMS
   DEVELOPING SWD ACROSS THE MID MS VALLEY WED MORNING THEN WILL SHIFT
   SWWD ACROSS AR AND INTO ERN OK DURING THE DAY. CURRENT RADAR TRENDS
   AS OF THIS WRITING DO NOT SUPPORT THIS SOLUTION...BUT IT CANNOT BE
   RULED OUT. OTHERWISE...EXPECT STRONG INSTABILITY TO DEVELOP AHEAD OF
   A WEAK SWD-MOVING BOUNDARY WITH LOW PRESSURE TROUGH FROM AR INTO WRN
   TN BY LATE AFTERNOON. NLY FLOW ALOFT WILL ALSO STRENGTHEN ON THE ERN
   PERIPHERY OF THE UPPER RIDGE...AND COULD SUPPORT SOME LONGER-LIVED
   CELLS CAPABLE OF LOCALIZED WIND OR HAIL...POSSIBLY AS FAR W AS AR
   AND ERN OK.