[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 271250
SWODY1
SPC AC 271249

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0749 AM CDT WED SEP 27 2006

VALID 271300Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE MIDWEST...LWR
OH VLY AND OZARKS...

...SYNOPSIS...
HIGHLY AMPLIFIED RIDGE-TROUGH PATTERN WILL PREVAIL ACROSS NOAM THIS
PERIOD.  LEAD IMPULSE NOW CROSSING WI SHOULD CONTINUE E ACROSS MI
AND SW ONTARIO AS STRONGER UPSTREAM DISTURBANCE NOW OVER ND DRIVES
SEWD INTO SRN MO/IL BY 12Z THURSDAY.

COLD FRONT NOW EXTENDING FROM THE UPR GRT LKS INTO KS WILL BE
STRONGLY REINFORCED LATER TODAY/TONIGHT AS ND IMPULSE SWEEPS SEWD.
THE FRONT SHOULD OVERTAKE LEAD WINDSHIFT/LEE TROUGH OVER THE
OZARKS/SRN PLNS LATE THIS AFTERNOON...AND REACH THE LWR GRTLKS...LWR
TN VLY AND CNTRL TX BY THURSDAY MORNING.

...MIDWEST SW INTO THE LWR OH VLY/OZARKS...
A BAND OF SHOWERS/STORMS SHOULD CONTINUE TO PRECEDE LEAD IMPULSE
CROSSING LWR MI...NRN IL AND NRN IND TODAY.  MODERATE UNIDIRECTIONAL
WLY FLOW AND MODEST INSTABILITY SUGGEST THAT THIS ACTIVITY SHOULD
REMAIN MOSTLY SUB-SEVERE...BUT GUSTY WINDS AND SMALL HAIL MAY
ACCOMPANY THE STRONGER STORMS.

A BIT LATER...MORE VIGOROUS STORMS EXPECTED TO FORM FROM MID TO LATE
AFTN THROUGH TONIGHT ALONG STRENGTHENING COLD FRONT FROM SE LWR
MI...NW OH...CNTRL/ERN IND AND ERN/SRN IL SW INTO THE OZARKS. 
MOISTURE WILL BE LIMITED BY LATE SEPTEMBER STANDARDS...WITH AVERAGE
SURFACE DEWPOINTS LIKELY TO REMAIN IN THE LOW-MID 50S. BUT LOW TO
MID LEVEL LAPSE RATES SHOULD STEEPEN GIVEN MODERATE TO STRONG
SURFACE HEATING AND DIFFERENTIAL THERMAL ADVECTION.  MLCAPE MAY
REACH 500 J/KG IN NRN IND/NRN OH...AND 1500 J/KG IN THE LWR OH
VLY/OZARKS.

LARGELY UNIDIRECTIONAL W OR WSWLY FLOW WILL PREVAIL ACROSS THE
SLIGHT RISK REGION...WITH 500 MB SPEEDS AROUND 40 KTS. THIS SETUP
SHOULD SUPPORT ORGANIZED LINE SEGMENTS/CLUSTERS OF STORMS...
INCLUDING POSSIBLE SUPERCELLS. BOWING SEGMENTS AND SUSTAINED
UPDRAFTS MAY YIELD HIGH WIND AND HAIL...ESPECIALLY FROM THE LWR OH
VLY INTO SRN MO/NRN AR...WHERE INSTABILITY/SHEAR COMBINATION SHOULD
BE GREATEST.  A LIMITED SEVERE THREAT MAY CONTINUE INTO LATE EVENING
OVER NRN/CNTRL AR...W TN AND WRN/CNTRL KY AS FORCING FOR ASCENT
INTENSIFIES IMMEDIATELY DOWNSTREAM FROM AMPLIFYING UPR TROUGH.

...MID/LWR MO VLY...
AREA OF STRONG UVV ASSOCIATED WITH ND IMPULSE HAS SUPPORTED
OVERNIGHT SHOWERS/TSTMS OVER ERN MT AND THE WRN DAKS.  AS THIS UVV
MAX CONTINUES SEWD...A SECONDARY REGION OF POSSIBLE SEVERE
CONVECTION MAY EVOLVE WITH SURFACE HEATING OVER SE SD AND NRN/ERN
NEB SE INTO WRN IA/NW MO.  SATELLITE SUGGESTS THAT CLOUDS WILL COVER
PARTS OF THE MID/LWR MO VLY THROUGH MIDDAY.  BUT WITH CORE OF
STRONGEST DCVA/MID LEVEL COOLING TRACKING OVER REGION FOLLOWING MAX
HEATING...AND WITH DEWPOINTS REMAINING IN THE UPR 40S DESPITE LOW
LEVEL CAA...SETUP MAY FOSTER DEVELOPMENT OF SCATTERED FAST-MOVING/
LOW-TOPPED TSTMS.  GIVEN PROXIMITY OF 50+ KT MID LEVEL JET CORE AND
COOL MID LEVEL TEMPS...THESE COULD YIELD A FEW SPOTS OF DAMAGING
WIND/HAIL.

..CORFIDI/GUYER.. 09/27/2006