[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 100555
SWODY1
SPC AC 100553

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT SUN SEP 10 2006

VALID 101200Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE TX PANHANDLE/NWRN OK
INTO A PART OF SWRN KS...

...SYNOPSIS...
00Z NAM/GFS ARE IN BETTER AGREEMENT THAN THE LAST FEW RUNS OF THESE
MODELS WITH RESPECT TO TIMING/AMPLIFICATION...AND INDICATE A BROAD
UPPER TROUGH MOVING SLOWLY EWD ACROSS THE CENTRAL U.S. TODAY.  A
SURFACE LOW ACCOMPANYING THIS SYSTEM SHOULD TRACK FROM NORTH CENTRAL
KS AT 12Z THIS MORNING TO NRN MO BY 12Z MONDAY.  MEANWHILE...SURFACE
FRONTS ARE NOT WELL DEFINED IN THE MODELS.  THE MEAN COLD FRONT
POSITION SHOULD EXTEND FROM NERN KS SWWD THROUGH NWRN OK INTO THE TX
PANHANDLE AT THE TIME OF PEAK HEATING.

...OK AND TX PANHANDLES/NWRN OK/PART OF SW KS...
SLIGHTLY STRONGER WLY MID LEVEL FLOW /UP TO 25 KT/ AND RESULTANT
EFFECTIVE BULK SHEAR VALUES AROUND 30 KT ARE EXPECTED ALONG THE SRN
PERIPHERY OF THE UPPER TROUGH ACROSS THIS REGION OF THE SRN PLAINS
THIS AFTERNOON.  MODEST MID LEVEL LAPSE RATES AROUND 6.5 C/KM
EXTENDING EWD ACROSS THE SLIGHT RISK AREA AND SURFACE DEWPOINTS IN
THE LOWER 60S WILL LIKELY SUPPORT AN AXIS OF MODERATE INSTABILITY
/MLCAPE 1000-1500 J/KG/ BY PEAK HEATING.  THUNDERSTORMS ARE EXPECTED
TO DEVELOP THIS AFTERNOON ALONG THE EXTENT OF THE COLD FRONT AND ANY
OUTFLOW BOUNDARIES LEFT OVER FROM CURRENT ACTIVITY OVER THE
CENTRAL/SRN PLAINS.  GREATEST SEVERE THREAT IS EXPECTED ACROSS THE
SLIGHT RISK AREA WHERE MODERATE INSTABILITY WILL BE COLOCATED WITH
STRONGER EFFECTIVE BULK SHEAR VALUES.  SEVERE THREAT SHOULD CONTINUE
INTO THE EARLY EVENING PRIOR TO BOUNDARY LAYER STABILIZATION.

...ELSEWHERE ACROSS THE SRN PLAINS TO NRN MO...
MID LEVEL LAPSE RATES ARE EXPECTED TO BE WEAKER WITH EWD EXTEND INTO
THE PLAINS...RESULTING IN LESS AVAILABLE INSTABILITY ALONG THE COLD
FRONT...ESPECIALLY FROM NERN KS INTO MO.  DESPITE THE WEAKER
INSTABILITY...MODELS SUGGEST EFFECTIVE SHEAR VALUES EXCEEDING 30 KT
ACROSS NERN KS/NRN MO MAY SUPPORT A GREATER SEVERE THREAT ACROSS
THESE AREAS THAN POINTS FARTHER S ACROSS KS.  HOWEVER...MODEL
UNCERTAINTIES AND LOW CONFIDENCE IN THE POSITION OF THE COLD FRONT
AT PEAK HEATING HAVE LED TO THE ISSUANCE OF BROAD 5% SEVERE
PROBABILITIES FOR HAIL AND WIND EXTENDING FROM THE TX S PLAINS
ACROSS CENTRAL/ERN KS TO NRN MO.

..PETERS/GUYER.. 09/10/2006