[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 220049
SWODY1
SPC AC 220048

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0748 PM CDT THU SEP 21 2006

VALID 220100Z - 221200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF SERN OK...NERN TX
AND SWRN AR...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL/SRN
PLAINS INTO MO AND AR...

...ERN PORTION OF CENTRAL/SRN PLAINS...
WATER VAPOR IMAGERY SHOWS A VIGOROUS UPPER LOW OVER NRN KS LIFTING
NNEWD INTO NEB IN RESPONSE TO UPSTREAM VORTICITY MAX DIGGING SEWD
ACROSS THE NRN INTERMOUNTAIN REGION.  OCCLUDED SURFACE LOW NORTH OF
CNK IS EXPECTED TO CONTINUE MOVING NEWD INTO ERN NEB TONIGHT.  NRN
PART OF SURFACE DRY LINE ARCING SWD FROM THE LOW ACROSS KS WILL MOVE
INTO ERN KS...WHILE SRN PART OF DRYLINE ACROSS CENTRAL OK AND NORTH
CENTRAL TX IS EXPECTED TO BECOME QUASI-STATIONARY AS STRONGEST
DYNAMIC FORCING LIFTS NWD WITH TIME.

A RELATIVELY NARROW WARM SECTOR HAS BECOME ESTABLISHED FROM
CENTRAL/ERN TX NWD INTO ERN PARTS OF OK AND KS WITH SURFACE DEW
POINTS IN THE LOW/MID 60S EXTENDING AS FAR NORTH AS NERN
OK...DROPPING INTO THE 50S IN ERN KS.  COLD AIR ALOFT AND STEEPER
LAPSE RATES ARE LOCATED IN THE IMMEDIATE PROXIMITY OF THE NRN KS
UPPER LOW...WITH PROGRESSIVELY WARMER MID LEVEL TEMPERATURES/WEAKER
LAPSE RATES SWD INTO THE LOW LEVEL MOIST AXIS ACROSS ERN OK AND
CENTRAL/ERN TX.  THIS IS RESULTING IN MLCAPE OF AROUND 1000 J/KG
OVER ERN PARTS OF OK AND TX.

EARLIER TORNADIC THUNDERSTORMS OVER CENTRAL KS HAVE MOVED NWD AND
WEAKENED...WHILE NEW STORMS ARE DEVELOPING FROM SERN KS ACROSS ERN
OK.  VAD AND PROFILERS EXHIBIT WINDS THAT VEER AND INCREASE IN SPEED
WITH HEIGHT...RESULTING IN STRONG DEEP LAYER VERTICAL SHEAR OF 50-60
KT...AND SRH OF 200-400 MS/S2 IN THE LOWEST 1-3 KM AGL.  THE WIND
PROFILES ARE STRONGLY SUPPORTIVE OF SUPERCELL DEVELOPMENT FOR STORMS
THAT CAN REMAIN DISCRETE...AND THE THREAT FOR TORNADOES WILL BE
ENHANCED BY RELATIVELY LOW LCL HEIGHTS AND FAVORABLE SHEAR/SRH IN
THE LOWEST 1 KM.  MODEL GUIDANCE FROM RUC...NAM AND SREF AGREE WITH
OBSERVATIONAL DATA SHOWING FOCUS ON THE SERN OK/NERN TX/SWRN AR
REGION FOR AN INCREASED SEVERE POTENTIAL THROUGH THE EVENING HOURS
AND THE HIGHEST SEVERE PROBABILITIES/MODERATE RISK REGION WILL BE
MAINTAINED OVER THIS AREA.

STORMS ARE LIKELY TO SPREAD NEWD INTO MO AND AR DURING THE OVERNIGHT
HOURS...CONSOLIDATING INTO ONE OF MORE MCS/S ARE THEY MOVE INTO A
REGION OF INCREASINGLY ELEVATED INSTABILITY.  ALTHOUGH THREAT FOR
TORNADOES AND DAMAGING WIND GUSTS IS EXPECTED TO DIMINISH LATER
TONIGHT...POTENTIAL FOR ISOLATED LARGE HAIL WILL LIKELY CONTINUE
THROUGH THE NIGHT ACROSS MO AND PARTS OF CENTRAL/ERN AR.

..WEISS.. 09/22/2006