[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 210600
SWODY1
SPC AC 210558

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT WED JUN 21 2006

VALID 211200Z - 221200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER CNTRL/SRN LOWER MI...MUCH
OF NRN IL...NRN IND AND NWRN OH...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL/SRN HIGH PLAINS
EWD THROUGH THE GREAT LAKES...

...SYNOPSIS...

BELT OF 40-60KT...CYCLONIC MID-LEVEL FLOW WILL PERSIST THROUGH THE
DAY ONE PERIOD FROM THE NRN PLAINS EWD INTO THE GREAT LAKES WITH A 
REGION OF HEIGHT FALLS SPREADING EWD ACROSS THIS SAME GENERAL AREA
IN ASSOCIATION WITH SHORT WAVE TROUGH CURRENTLY OVER SRN
SASKATCHEWAN/MANITOBA. A LOWER LATITUDE IMPULSE NOW OVER NEB WILL
TRANSLATE EWD TODAY...REACHING THE SWRN GREAT LAKES BY MID/LATE
AFTERNOON...PRIOR TO MOVING RAPIDLY TOWARD THE HUDSON VALLEY BY
THURSDAY MORNING.

IN THE LOW-LEVELS...WEAK WARM FRONT FROM N-CNTRL IA INTO SWRN IND
WILL LIFT NWD THROUGH THE CNTRL GREAT LAKES TODAY WITH TRAILING COLD
FRONT BECOMING PROGRESSIVELY MORE QUASI-STATIONARY AND W-E ORIENTED
FROM NRN IL THROUGH SRN IA/NRN MO AND NERN INTO W-CNTRL KS. 
MEANWHILE...A SECONDARY...STRONGER COLD FRONT WILL PUSH SEWD FROM
THE UPPER MS VALLEY SEWD INTO THE WRN GREAT LAKES BY THIS EVENING.

...GREAT LAKES WWD INTO THE LOWER MO VALLEY...

AN ACTIVE SEVERE WEATHER DAY IS ANTICIPATED...PARTICULARLY ACROSS
THE SRN GREAT LAKES WHERE THE THREAT OF WIDESPREAD DAMAGING WINDS
WILL EXIST.

MCS CURRENTLY EVOLVING OVER NEB WILL CONTINUE TO MOVE/DEVELOP EWD
THROUGH IA PRIOR TO 21/12Z...DRIVEN LARGELY BY LOW-LEVEL WAA ALONG
40-45 KT SWLY LLJ.  THOUGH SOME DIURNAL WEAKENING MAY OCCUR...
RE-INTENSIFICATION OF CONVECTIVE ELEMENTS COMPRISING MCS WILL LIKELY
OCCUR BY AFTERNOON OVER PORTIONS OF ERN IA/SRN WI/NRN IL. 
THEREAFTER...INTENSIFYING MCS SHOULD RAPIDLY MOVE EWD THROUGH NRN
IND...CNTRL AND SRN LOWER MI AND NRN OH THIS AFTERNOON AND
EVENING...PERHAPS AS FAR E AS WRN AND CNTRL PA/NY OVERNIGHT.

A MOIST BOUNDARY-LAYER CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S
TO LOWER 70S COUPLED WITH STEEP LOW TO MID-LEVEL LAPSE RATES WILL
CONTRIBUTE TO MLCAPES OF 2000-3000 J/KG WITHIN INFLOW AIR MASS OVER
CNTRL IL INTO NRN AND CNTRL PART OF IND/OH.  THIS INSTABILITY IN
CONJUNCTION WITH 40-50 KT DEEP WLY SHEAR WILL BE SUPPORTIVE OF
EMBEDDED SUPERCELLS AND BOW ECHOES CAPABLE OF CORRIDORS OF DAMAGING
WINDS AND LARGE HAIL /SOME SIGNIFICANT/.  A TORNADO OR TWO WILL BE
POSSIBLE...ESPECIALLY WITH ANY MORE DISCRETE CELLS DEVELOPING ALONG
SRN FLANK OF LARGER CONVECTIVE SYSTEM.

ADDITIONAL BACKBUILDING STORM DEVELOPMENT WILL BE POSSIBLE THIS
AFTERNOON INTO TONIGHT FROM SRN IA/NRN MO WWD INTO NRN KS ALONG
QUASI-STATIONARY BOUNDARY OR COMPOSITE BOUNDARY MODULATED BY MCS
OUTFLOW.  GIVEN MODERATE TO STRONG INSTABILITY /MLCAPES OF 2000-3000
J/KG/ AND 30-40 KTS OF DEEP LAYER SHEAR...POTENTIAL WILL EXIST FOR
ORGANIZED SEVERE STORMS INCLUDING SUPERCELLS CAPABLE OF LARGE HAIL
AND DAMAGING WINDS.

OTHER SEVERE STORMS WITH HIGH WINDS/HAIL MAY DEVELOP THIS AFTERNOON
OVER PORTIONS OF WI...PERHAPS WWD INTO MN ALONG COLD FRONT PUSHING
SEWD THROUGH AREA.  THERE IS SOME UNCERTAINTY AS TO THE DEGREE OF
INSTABILITY ACROSS PRE-FRONTAL AIR MASS OWING TO RESIDUAL
CONVECTIVELY-PROCESSED FROM EARLIER MCS.

...CNTRL/SRN HIGH PLAINS...

MODEST BOUNDARY-LAYER MOISTURE /DEWPOINTS IN THE MID 40S TO MID
50S/...COMBINED WITH STEEP LAPSE RATES WILL SUPPORT MODERATE
AFTERNOON INSTABILITY /MLCAPES OF 1000-1500 J/KG/ FROM VICINITY OF
FRONTAL BOUNDARY NWD INTO POST-FRONTAL AIR MASS.  OROGRAPHIC FORCING
WILL LARGELY DRIVE DIURNAL TSTM DEVELOPMENT BY MID TO LATE
AFTERNOON...GIVEN THE ABSENCE OF ANY DISCERNIBLE IMPULSES IN WATER
VAPOR IMAGERY. MID-LEVEL WIND FIELDS ARE NOT FORECAST TO BE
PARTICULARLY STRONG /20-25 KTS/...THOUGH ELY LOW-LEVEL WINDS WILL
RESULT IN 30-35 KTS OF DEEP-LAYER SHEAR...SUPPORTIVE OF ROTATING
UPDRAFTS.  LARGE HAIL AND LOCALLY DAMAGING WINDS WILL BE THE MAIN
SEVERE WEATHER HAZARDS...WITH THE POTENTIAL FOR MCS DEVELOPMENT OVER
WRN KS TONIGHT.

THE DAMAGING WIND/HAIL THREAT WILL EXIST SWD TO THE RATON MESA AREA
AND SECONDARY SURFACE LOW OVER THE NWRN TX PNHDL WITHIN HOTTER AND
DEEPER MIXED BOUNDARY-LAYER ENVIRONMENT.

..MEAD.. 06/21/2006