[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 241231
SWODY1
SPC AC 241229

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT MON APR 24 2006

VALID 241300Z - 251200Z

...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT ACROSS PARTS OF NRN OK AND SRN KS....

...THERE IS A SLGT RISK OF SVR TSTMS THROUGH TONIGHT ELSEWHERE FROM
NRN KS SWD TO CENTRAL TX...AND EWD TO NW AR/MO/SRN IL....

...SYNOPSIS...
THE CLOSED MID LEVEL LOW OVER THE SRN GREAT BASIN IS EVOLVING INTO
AN OPEN WAVE...AND THIS SYSTEM WILL EJECT EWD TO THE HIGH PLAINS BY
TONIGHT.  A SEPARATE NRN STREAM WAVE WILL MOVE FROM MANITOBA TO THE
UPPER GREAT LAKES.  IN THE WAKE OF THIS NRN STREAM TROUGH...A
SURFACE RIDGE WILL BUILD SEWD ACROSS THE PLAINS...DRIVING A COLD
FRONT SEWD ACROSS OK/NW TX AND THE MID MS VALLEY BY THE END OF THE
PERIOD.  AN INITIAL LEE CYCLONE OVER SW KS THIS MORNING IS EXPECTED
TO DEVELOP EWD ALONG AN E-W BAROCLINIC ZONE ACROSS KS/MO...OR
PERHAPS ALONG A COMPOSITE OUTFLOW BOUNDARY LINGERING ACROSS NRN
OK...IN ADVANCE OF THE GREAT BASIN TROUGH.  THE SURFACE LOW AND
THESE SURFACE BOUNDARIES WILL FOCUS THE SEVERE STORM THREAT THROUGH
EARLY TONIGHT ACROSS KS AND NRN OK.

...KS/OK/MO AREA THROUGH TONIGHT...
THE FIRST MCS IN THE SEQUENCE HAS DISSIPATED OVER SE MO...LEAVING AN
OUTFLOW BOUNDARY FROM NRN AR INTO NRN OK.  A SECOND SMALL MCS IS
WEAKENING OVER NE OK/NW AR...AND THIS CONVECTION IS REINFORCING THE
EARLIER OUTFLOW ACROSS NRN OK. OTHER ELEVATED STORMS PERSIST ACROSS
CENTRAL/NE KS AND SE NEB IN ASSOCIATION WITH WAA AND LIFT ALONG THE
SURFACE COLD FRONT.  GIVEN THE RELATIVELY WIDESPREAD CONVECTION
ACROSS KS...THE EFFECTIVE SURFACE BOUNDARY MAY END UP BEING THE
RESIDUAL OUTFLOW NEAR THE KS/OK BORDER BY AFTERNOON.  A FEED OF
UNDISTURBED WARM SECTOR AIR /WITH BOUNDARY LAYER DEWPOINTS OF 62-64
F/ WILL PERSIST TODAY ACROSS CENTRAL AND WRN OK INTO THE OUTFLOW
BOUNDARY NEAR THE KS/OK BORDER. STRONG SURFACE HEATING BENEATH STEEP
MID LEVEL LAPSE RATES WILL CONTRIBUTE TO MLCAPE VALUES OF 2000-3000
J/KG IN THE WARM SECTOR...AND PERHAPS 1000-2000 J/KG IN THE ZONE
BETWEEN THE OUTFLOW BOUNDARY AND RESIDUAL E-W BAROCLINIC ZONE IN KS.


THERE IS SOME UNCERTAINTY REGARDING THE EVOLUTION OF THE ONGOING
STORMS IN KS.  HOWEVER...IT APPEARS LIKELY THAT ADDITIONAL STORMS
WILL FORM BY MID AFTERNOON NEAR THE SURFACE TRIPLE POINT...CLOSE TO
A LINE FROM P28-END.  INCREASING MID-UPPER WSWLY FLOW...ALONG WITH
BACKED LOW-LEVEL WINDS NEAR THE OUTFLOW BOUNDARY AND E OF THE
SURFACE LOW...WILL PROVIDE SUFFICIENT VERTICAL SHEAR FOR SUPERCELLS.
 VERY LARGE HAIL AND A FEW TORNADOES WILL BE POSSIBLE DURING THE
LATE AFTERNOON/EVENING...ESPECIALLY IF THE OUTFLOW BOUNDARY CAN
MAINTAIN ITS IDENTITY WITH A BELT OF BACKED LOW-LEVEL FLOW AND MID
60 DEWPOINTS.  LATER DURING THE EVENING...CONVECTION SHOULD GROW
UPSCALE INTO ANOTHER MCS WITH LARGE HAIL AND DAMAGING WINDS ACROSS
SRN KS AND NRN OK...POSSIBLY REACHING SW MO AND NW AR LATE TONIGHT. 
OTHER MORE ISOLATED STORMS MAY FORM ALONG THE COLD FRONT OVERNIGHT
INTO CENTRAL TX...WHILE THE ERN EXTENT OF THE SEVERE THREAT WILL BE
LIMITED BY GRADUALLY WEAKENING INSTABILITY OVERNIGHT ACROSS MO/AR.

..THOMPSON/TAYLOR.. 04/24/2006