[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 191739
SWODY2
SPC AC 191738

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1238 PM CDT MON JUN 19 2006

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MS VALLEY INTO
CO...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NEW ENGLAND...

...MID MS VALLEY...

NRN ROCKIES SHORTWAVE TROUGH WILL FLATTEN UPPER RIDGE FROM THE
NRN/CNTRL PLAINS INTO THE MID MS VALLEY REGION TUESDAY.  WLY FLOW IN
ASSOCIATION WITH THIS FEATURE WILL MAINTAIN A STOUT CAP ACROSS THE
CNTRL PLAINS MOST OF THE PERIOD.

LATEST THINKING IS DAY1 CONVECTION ACROSS THE NRN HIGH PLAINS WILL
PROGRESS INTO THE DAKOTAS EARLY IN THE PERIOD AIDED BY LOW LEVEL
WARM ADVECTION THAT WILL BECOME FOCUSED OVER THE MID/UPPER MS VALLEY
LATER IN THE DAY.  ELEVATED CONVECTION SHOULD SPREAD/DEVELOP SEWD
INTO PORTIONS OF MN/IA ALONG THE ERN EDGE OF THE STRONG PLAINS CAP. 
THIS ACTIVITY MAY GENERATE HAIL WHILE ROOTED ABOVE THE BOUNDARY
LAYER...BUT WITHIN STEEP MID LEVEL LAPSE RATE PLUME.  OF MORE
CONCERN IS THE POTENTIAL FOR BOUNDARY LAYER THUNDERSTORM DEVELOPMENT
LATER IN THE DAY AHEAD OF COLD FRONT.  IT APPEARS STRONG LOW LEVEL
HEATING WILL OCCUR ACROSS WRN IA/ERN NEB...WHICH WILL BE NECESSARY
FOR THE REMOVAL OF INHIBITION...AND CONVECTION SHOULD EVOLVE BY LATE
AFTERNOON WITHIN A POTENTIALLY VERY UNSTABLE AIRMASS.  FORECAST
SOUNDINGS FOR THIS REGION SUGGEST SUPERCELL STRUCTURES ARE LIKELY
WITH VERY LARGE HAIL POSSIBLE. WITH TIME...STORM MERGERS MAY RESULT
IN MCS EVOLUTION WHICH COULD LEAD TO A MORE ORGANIZED DAMAGING WIND
THREAT AS ACTIVITY SPREADS SEWD TOWARD NRN IL DURING THE OVERNIGHT
HOURS.

...ERN CO/KS...

UPSLOPE FLOW IN THE WAKE OF SWD SAGGING FRONTAL BOUNDARY WILL ALLOW
HIGHER RH BOUNDARY LAYER TO SPREAD WWD INTO NERN CO TUESDAY
AFTERNOON.  TAIL END OF PLAINS UPPER TROUGH WILL BRUSH THIS REGION
ENHANCING LARGE SCALE ASCENT AND AIDING UPSLOPE COMPONENT INTO EAST
SLOPES.  THUNDERSTORMS WILL DEVELOP BY MID-LATE AFTERNOON AND SPREAD
SEWD TOWARD WRN KS WITH MORE THAN ENOUGH SHEAR FOR SUPERCELLS. 
LARGE HAIL SHOULD BE THE PRIMARY SEVERE THREAT WITH
COVERAGE/INTENSITY OF STORMS EXPECTED TO BE MODULATED BY THE DEGREE
OF BOUNDARY LAYER MOISTURE THAT CAN RETURN TO THIS REGION BEFORE
INITIATION.  IF SUFFICIENT MOISTURE DOES RETURN...AN MCS COULD
EASILY EVOLVE OVER THE CNTRL HIGH PLAINS TUESDAY NIGHT.

...NEW ENGLAND/MIDDLE ATLANTIC...

TIMING OF UPPER TROUGH AND THE PROGRESSION OF ASSOCIATED LOW LEVEL
WIND SHIFT WILL PLAY AN IMPORTANT ROLE IN DEEP CONVECTION ACROSS NEW
ENGLAND DURING THE DAY2 PERIOD.  LATEST NAM GUIDANCE SUGGEST LOW
LEVEL CONFLUENCE ZONE WILL HAVE SHIFTED INTO CNTRL ME...STRETCHING
SWWD INTO CNTRL MA BY 18Z..AND THIS IS SUPPORTED BY 12Z GFS.  A
NARROW AXIS OF MODEST INSTABILITY WILL EVOLVE ALONG THIS WIND SHIFT
WHICH SHOULD SUPPORT ORGANIZED DEEP CONVECTIVE DEVELOPMENT BY MID
DAY.  RAPID BOUNDARY LAYER HEATING WILL STEEPEN LOW LEVEL LAPSE
RATES AND FORECAST SHEAR PROFILES SUGGEST SUFFICIENT WLY FLOW TO
ALLOW STORMS TO PROGRESS TOWARD COASTAL AREAS DURING THE AFTERNOON. 
LARGE HAIL/DAMAGING WINDS MAY OCCUR WITH THIS ACTIVITY.

..DARROW.. 06/19/2006