[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 210057
SWODY1
SPC AC 210056

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0756 PM CDT TUE JUN 20 2006

VALID 210100Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT FROM THE CNTRL HIGH
PLAINS INTO THE MIDWEST AND WRN GREAT LAKES...

...WRN SD INTO ERN CO/WRN KS...

CLUSTERS OF TSTMS WITH EMBEDDED SUPERCELLS ARE IN PROGRESS FROM SWRN
SD INTO NERN CO WITHIN POST-FRONTAL ENVIRONMENT CHARACTERIZED BY
STEEP LOW TO MID-LEVEL LAPSE RATES AND MODEST BOUNDARY LAYER
MOISTURE WHICH IS CONTRIBUTING TO MLCAPES AS HIGH AS 3000-3500 J/KG
PER LBF SOUNDING.  ELY TO NELY LOW-LEVEL WINDS COUPLED WITH 40-50 KT
WLY MID-LEVEL FLOW IS RESULTING IN MORE THAN SUFFICIENT DEEP-LAYER
SHEAR FOR SPLITTING SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING
WINDS. A TORNADO OR TWO ALSO REMAINS POSSIBLE WITH ANY RIGHT-MOVING
SUPERCELL MEMBERS...PARTICULARLY OVER FAR NERN CO INTO SWRN NEB.

STORMS MAY EVOLVE INTO A MCS WITH A DAMAGING WIND AND SEVERE HAIL
THREAT SPREADING EWD ACROSS NEB AND NRN KS TONIGHT.  OTHER SEVERE
STORMS CAPABLE OF HIGH WINDS AND SEVERE HAIL MAY DEVELOP ALONG
SURFACE FRONT OVER W-CNTRL INTO N-CNTRL KS...ESPECIALLY AS LLJ
INCREASES THIS EVENING AND EFFECTIVELY ENHANCES CONVERGENCE WITHIN
FRONTAL ZONE.

...CNTRL/ERN NEB EWD/NEWD INTO THE UPPER MIDWEST/WRN GREAT LAKES...

COMPLEX SURFACE PATTERN EXISTS EWD INTO THE MIDWEST THIS EVENING AS
A RESULT OF OUTFLOW FROM EARLIER MCS WHICH HAS SINCE DECAYED.  ERN
EXTENSION OF NWRN KS COLD FRONT STRETCHES NEWD THROUGH S-CNTRL NEB
TO NWRN IA...WHERE IT BECOMES MORE QUASI-STATIONARY INTO SRN MN. 
EFFECTIVE WARM FRONT STRETCHES FROM INTERSECTION WITH
COLD/STATIONARY FRONT OVER NWRN IA SEWD TO NEAR DSM AND INTO N-CNTRL
MO.  A SECONDARY NW-SE BOUNDARY ALSO EXTENDS FROM NEAR DSM SEWD
THROUGH SERN IA THROUGH CNTRL IL INTO SWRN IND.

00Z OMA SOUNDING SUGGESTS THAT AIR MASS HAS BECOME WEAKLY CAPPED
WITH MLCAPES OF AROUND 3000 J/KG.  DIURNAL TSTM DEVELOPMENT REMAINS
POSSIBLE ALONG ANY OF THESE ABOVE-MENTIONED BOUNDARIES...THOUGH
STORM INITIATION APPEARS MORE LIKELY THIS EVENING ACROSS ERN IA SERN
MN INTO WI AND IL AS SWLY LLJ INCREASES...ENHANCING ISENTROPIC
ASCENT NE/E OF FRONTAL ZONE.  MUCH OF THIS ACTIVITY WILL BE ELEVATED
ABOVE STABLE SURFACE LAYER E OF SURFACE BOUNDARIES...THOUGH A FEW
SURFACE-BASED STORMS MAY ANCHOR WHERE POTENTIAL FOR A COUPLE
TORNADOES STILL EXISTS GIVEN THE RELATIVELY STRONG LOW AND
DEEP-LAYER SHEAR.

OTHERWISE...EXPECT THE PRIMARY SEVERE WEATHER THREAT TO BE LARGE
HAIL AND ISOLATED DAMAGING WINDS WITH THIS THREAT SPREADING E OF
LAKE MI LATE TONIGHT IN ASSOCIATION WITH THE EXPANDING WAA PATTERN.

FARTHER TO THE W OVER CNTRL/ERN NEB INTO WRN IA...STORMS MAY EITHER
DEVELOP ALONG SURFACE BOUNDARY THIS EVENING AS LLJ INCREASES...OR
MOVE INTO THE AREA FROM THE W LATER TONIGHT.  GIVEN THE MODERATE
INSTABILITY AND 45-55 KTS OF DEEP-LAYER...POTENTIAL WILL EXIST FOR
SUPERCELLS AND BOWING CLUSTERS CAPABLE OF LARGE HAIL AND DAMAGING
WINDS...PERHAPS EVEN A TORNADO OR TWO.

...NEW ENGLAND INTO THE LOWER HUDSON VALLEY...

CLUSTERS OF STRONG STORMS CONTINUE THIS EVENING OVER PORTIONS OVER
ERN NH INTO SWRN ME...AS WELL AS OVER PORTIONS OF MA/CT/RI.  WATER
VAPOR IMAGERY SUGGESTS THAT THIS CONVECTION IS WITHIN ZONE OF
RELATIVELY STRONG LARGE-SCALE FORCING FOR ASCENT AHEAD OF SHORT WAVE
TROUGH MOVING THROUGH THE ST. LAWRENCE AND HUDSON VALLEYS.  THE
STRONGEST STORMS WILL REMAIN CAPABLE OF ISOLATED DAMAGING WINDS
THROUGH 02Z WITH STORMS WEAKENING THEREAFTER.

..MEAD.. 06/21/2006