[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 160525
SWODY2
SPC AC 160523

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1223 AM CDT SUN APR 16 2006

VALID 171200Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE CAROLINAS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER WRN PARTS OF SD AND NEB...

...SYNOPSIS...

AMPLIFIED LONG WAVE PATTERN IS FORECAST THROUGH THE DAY TWO
PERIOD...CHARACTERIZED BY UPPER LOWS OVER THE GULF OF AK AND OVER
THE CANADIAN MARITIMES...AND EVOLVING UPPER LOW OVER THE NRN HIGH
PLAINS.  BETWEEN THESE FEATURES...HIGH AMPLITUDE RIDGE WILL EXIST
FROM HUDSON BAY/WRN QUEBEC SWWD INTO THE GREAT LAKES...AND A WEAKER
UPSTREAM RIDGE FROM THE CANADIAN ROCKIES INTO THE PACIFIC NW.

IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH A WEAKENING
MID-LEVEL VORTICITY MAXIMUM WILL DEVELOP SEWD FROM ERN KY INTO SC BY
AFTERNOON WITH ASSOCIATED COLD FRONT PUSHING SWD THROUGH THE
PIEDMONT AND COASTAL PLAIN.  OVER THE PLAINS...SURFACE PATTERN
BECOMES MORE COMPLEX.  PACIFIC COLD FRONT WILL PUSH EWD OUT OF THE
NRN AND CNTRL ROCKIES INTO THE HIGH PLAINS WITH LEE CYCLONE EVOLVING
ALONG THIS BOUNDARY OVER SERN WY MONDAY AFTERNOON.  A DRY LINE OR
LEE TROUGH WILL EXTEND SWD FROM THIS LOW INTO WRN PORTIONS OF KS AND
TX...WITH ATTENDANT WARM FRONT SLOWLY LIFTING NWD THROUGH KS AND
NEB.

...CAROLINAS...

CLUSTERS OF TSTMS ARE EXPECTED TO BE ONGOING AT THE ONSET OF THE
FORECAST MONDAY MORNING INVOF SURFACE LOW AND MID-LEVEL DISTURBANCE
OVER PORTIONS OF THE OH VALLEY INTO CNTRL APPALACHIANS.  THIS
ACTIVITY WILL LIKELY INTENSIFY BY AFTERNOON AS IT CRESTS HIGHER
TERRAIN AND MOVES INTO AN ENVIRONMENT CHARACTERIZED BY STEEP
LOW-LEVEL LAPSE RATES...MOIST BOUNDARY-LAYER CONDITIONS AND
RESULTANT WEAK TO MODERATE INSTABILITY.

FORECAST SOUNDINGS WITHIN PRE-FRONTAL AIR MASS OVER THE PIEDMONT AND
COASTAL PLAIN INDICATE LARGELY UNIDIRECTIONAL WLY OR WSWLY WINDS
THROUGH THE DEPTH OF THE BUOYANCY LAYER WITH SUFFICIENT DEEP-LAYER
SPEED SHEAR /40-45 KTS/ TO SUPPORT ORGANIZED SEVERE STORMS.  THE
MODEST MID-LEVEL LAPSE RATES WILL LIMIT A MORE SUBSTANTIAL HAIL
THREAT WITH DAMAGING WINDS LIKELY WITH THE MOST INTENSE STORMS.

...SD / NEB...

BOUNDARY-LAYER IS EXPECTED TO REMAIN RELATIVELY DRY AHEAD OF PACIFIC
COLD FRONT EMERGING FROM THE ROCKIES WITH DEWPOINTS REMAINING
LARGELY IN THE 30S AND 40S.  MODEL GUIDANCE SUGGESTS THAT PRIMARY
LOW-LEVEL MOISTURE AXIS WILL BE FOCUSED ALONG RETREATING WARM FRONT
WITH 50-55 F DEWPOINTS ADVECTING NWWD INTO CNTRL NEB BY MONDAY
NIGHT.

FRONTAL CONVERGENCE COUPLED WITH INCREASED LARGE-SCALE FORCING AHEAD
OF APPROACHING MID-LEVEL TROUGH ARE EXPECTED TO CONTRIBUTE TO TSTM
DEVELOPMENT BY AFTERNOON INTO EVENING ALONG COLD FRONT FROM THE WRN
DAKOTAS INTO SERN WY AND NWRN NEB WITHIN WEAKLY UNSTABLE
ENVIRONMENT.  DESPITE THE MARGINAL INSTABILITY...THE STEEP LAPSE
RATES AND RELATIVELY STRONG VERTICAL SHEAR PROFILES SUGGEST THE
POTENTIAL FOR A FEW ORGANIZED/ROTATING STORMS CAPABLE OF DAMAGING
WINDS AND LARGE HAIL.

THIS ACTIVITY WILL LIKELY MOVE/DEVELOP EWD ACROSS WRN SD AND
NWRN/N-CNTRL NEB MONDAY NIGHT /PERHAPS BECOMING MORE ELEVATED WITH
EWD EXTENT/ WITH A CONTINUING THREAT OF MAINLY SEVERE HAIL.

..MEAD.. 04/16/2006