[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 270545
SWODY1
SPC AC 270544

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1244 AM CDT WED SEP 27 2006

VALID 271200Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDWEST SWWD ACROSS
THE LWR OH VLY TO THE OZARKS...

...SYNOPSIS...
A POTENT NRN STREAM WILL CONTINUE TO DIG SEWD AND BEGIN TO CARVE OUT
A COLD LONGWAVE TROUGH ACROSS THE ERN TWO-THIRDS OF THE COUNTRY WED.
 THE LEAD IMPULSE MOVING ACROSS THE UPPER MS VLY EARLY WED WILL
QUICKLY TRANSLATE NEWD INTO SERN CANADA AS A MORE POTENT DISTURBANCE
DIGS SEWD FROM SRN ALBERTA INTO THE DAKS AND MID-MS VLY WED AND WED
NIGHT. 

IN THE LWR LVLS...WEAK COLD FRONT ASSOCD WITH THE FIRST WAVE WILL
SETTLE ACROSS THE GRTLKS...MIDWEST AND SRN PLAINS BY WED NOON. AS
THE STRONG IMPULSE DIGS SEWD...A POLAR FRONT WILL SURGE
SEWD...REACHING THE WEAKER FRONT LATE WED AFTN...THEN SWEEP SEWD
ACROSS THE GRTLKS...OH VLY...OZARKS AND SRN PLAINS BY 12Z THU.

...MIDWEST SWWD INTO THE LWR OH VLY AND OZARKS...
AS THE LEAD WAVE SWINGS E THEN NEWD THROUGH THE CNTRL GRTLKS...A
BAND OF CONVECTION WILL ACCOMPANY THE ASSOCD FRONT ACROSS THE CNTRL
GRTLKS FROM WED MORNING INTO THE EARLY AFTN.  THIS ACTIVITY SHOULD
MOSTLY BE SUB-SEVERE...BUT GUSTY WINDS AND PERHAPS SMALL HAIL MAY
ACCOMPANY THE STRONGER STORMS.

MAIN SEVERE THREAT WILL OCCUR FROM MID-LATE WED AFTN INTO THE NIGHT
FROM THE MIDWEST SWWD TO THE OZARKS.  SWLY LOW-LVL FLOW WILL
TRANSPORT/MAINTAIN LOW-MID 50S SFC DEW POINTS NEWD ALONG/AHEAD OF
THE WEAKER FRONT THROUGH WED AFTN.  BOUNDARY LAYER SHOULD HEAT
RAPIDLY AND CONTRIBUTE TO MLCAPES RANGING FROM 500 J/KG ACROSS SERN
LWR MI TO 1500 J/KG IN THE LWR OH VLY AND OZARKS.  

HEIGHTS WILL GRADUALLY FALL THROUGHOUT THE DAYTIME...BUT STRONGEST
FALLS WILL OCCUR BY LATE WED AFTN.  STRONG LARGE SCALE
ASCENT...COOLING TEMPERATURES ALOFT AND INCREASING FRONTAL FORCING
SHOULD BE FAVORABLE FOR TSTM INITIATION FROM SERN LWR MI ACROSS
IND...SRN IL...SERN MO AND NRN AR NEAR/AFTER PEAK HEATING.  

VERTICAL SHEAR WILL BE MORE THAN SUFFICIENT FOR ORGANIZED
STORMS...PROBABLY IN THE FORM OF LINE SEGMENTS.  SUPERCELLS WILL BE
POSSIBLE...PRIMARILY ACROSS THE LWR OH VLY WHERE MORE INSTABILITY
WILL BE AVAILABLE FOR SUSTAINED UPDRAFTS.  OTHERWISE...GIVEN THE
INCREASING UNIDIRECTIONALITY TO THE WIND FIELDS WITH TIME...ANY LINE
SEGMENT COULD CONTAIN BOWS/LEWPS.  DAMAGING WINDS AND LARGE HAIL
WILL BE THE PRIMARY THREATS.  SOME SEVERE THREAT WILL LIKELY
CONTINUE INTO THE EVE HOURS EWD INTO PARTS OF OH...NWRN/WRN KY AND
NWRN TN.

...MID/LWR MO VLY...
A SECONDARY REGION OF POSSIBLE SEVERE TSTMS WILL EVOLVE WED AFTN
FROM PARTS OF ERN NEB SEWD INTO NWRN MO.  CORE OF STRONGEST DCVA
ASSOCD WITH THE STRONGER IMPULSE WILL TRACK SEWD ACROSS THIS REGION
BETWEEN 18-00Z.  LAPSE RATES WILL STRONGLY STEEPEN AS H5
TEMPERATURES AOB MINUS 20 DEG C SURGE SEWD ATOP RESIDUAL 50S DEW
POINTS.  IF BOUNDARY LAYER CAN HEAT...A BAND OF LOW-TOPPED AND
FAST-MOVING TSTMS WILL DEVELOP GIVING POSSIBLE DAMAGING WINDS/HAIL. 
LOW-PROBABILITIES OF SEVERE WILL BE INTRODUCED...BUT IF
THERMODYNAMICS APPEAR TO BE MORE FAVORABLE...A HIGHER RISK COULD BE
ADDED IN LATER FCSTS.

..RACY.. 09/27/2006