[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 091237
SWODY1
SPC AC 091235

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0735 AM CDT TUE MAY 09 2006

VALID 091300Z - 101200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PORTIONS OF ERN OK AND NWRN
AR...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OK/TX PANHANDLE REGION
TO THE CENTRAL GULF COAST...

...SYNOPSIS...
A SERIES OF FAST MOVING SHORTWAVE TROUGHS ARE EVIDENT ON WV IMAGERY
THIS MORNING EJECTING AWAY FROM BROADER MID/UPPER LEVEL TROUGH OVER
THE ROCKIES.  ONE SYSTEM IS NOW MOVING ACROSS CENTRAL TX AND WILL
OVERSPREAD THE LOWER MS RIVER VALLEY/CENTRAL GULF COAST REGION
TODAY. ANOTHER APPEARS TO BE MOVING INTO THE CENTRAL ROCKIES WHICH
IS FORECAST TO BECOME BETTER DEFINED AS IT SHIFTS ACROSS THE SRN
HIGH PLAINS AND OVER OK/KS LATER TONIGHT.  AT THE SURFACE...PRIMARY
COLD FRONT NOW EXTENDS FROM CENTRAL IA INTO W-CENTRAL TX WHICH HAS
BEEN CONVECTIVELY-REINFORCED ACROSS NERN/CENTRAL OK FROM ONGOING MCS
NOW MOVING INTO THE OZARK REGION.  IN ADDITION...WEAK LOW CENTER WAS
ANALYZED OVER SWRN OK ALONG COLD FRONT/DRY LINE TRIPLE POINT...WITH
WARM FRONT DELINEATING VERY MOIST/MARINE AIR EXTENDING FROM SRN LA
INTO CENTRAL OK.

...SRN HIGH PLAINS INTO THE LOWER MS RIVER VALLEY/MID SOUTH...
FORECAST REMAINS COMPLEX THIS MORNING DUE TO UNCERTAINTY ABOUT
EFFECTS OF ONGOING MCS.  09Z RUC MAINTAINS SSWLY LLJ INTO NRN AR
THROUGH THE MORNING AND SHOULD SUPPORT CONTINUED STRONG/SEVERE
THUNDERSTORMS ACROSS THE OZARK PLATEAU AND NRN AR WITH THREATS OF
LARGE HAIL AND DAMAGING WINDS. ACTIVITY MAY INTENSIFY INTO THE
BOOTHEEL REGION OF MO/MID SOUTH LATER THIS MORNING/EARLY THIS
AFTERNOON ALONG NOSE OF THIS JET AS MODERATE INSTABILITY DEVELOPS. 
VERTICAL MOTION SHOULD BECOME QUITE WEAK ACROSS THE REGION FOR MUCH
OF THE DAY...THOUGH ABUNDANT MOISTURE WITH SURFACE DEW POINTS IN THE
LOWER TO MID 70S AND VERY STEEP LAPSE RATES WILL SUPPORT EXTREMELY
UNSTABLE AIR MASS.  HOWEVER...AREA WILL BE STRONGLY CAPPED UNDER
10-12C H7 TEMPERATURES.  ISOLATED DIURNAL THUNDERSTORMS MAY DEVELOP
IF CAP CAN BE BREACHED LATER TODAY ALONG THE NUMEROUS SURFACE
BOUNDARIES WHERE HEATING/CONVERGENCE WILL BECOME MAXIMIZED.  MORE
LIKELY REGION FOR DIURNAL DEVELOPMENT MAY BE ALONG DRY LINE INTO
CENTRAL TX WHERE CLEAR SKIES WILL SUPPORT UNSEASONABLY WARM
TEMPERATURES APPROACHING 100F AND ELIMINATE CAP BY 22Z.  GIVEN VERY
STRONG INSTABILITY AND 40-50 KT EFFECTIVE SHEAR...ANY STORM/S WHICH
CAN ERUPT THIS AFTERNOON WILL BECOME SUPERCELLS QUICKLY WITH
ENHANCED THREAT OF VERY LARGE HAIL AND ISOLATED TORNADOES. 
HOWEVER...LACK OF A LOW LEVEL JET OVER THE REGION MAY LIMIT ANY
SUSTAINED TORNADO THREAT FOR MUCH OF THE DAY.

APPEARS MOST LIKELY SCENARIO FOR WIDESPREAD SEVERE THUNDERSTORMS MAY
EVOLVE OUT OF THE HIGH PLAINS AHEAD OF SHORTWAVE TROUGH NOW MOVING
INTO THE CENTRAL ROCKIES.  BOTH RUC AND GFS INDUCE WEAK PRESSURE
FALLS AND SUBSEQUENT VEERING RESPONSE TO THE SURFACE WINDS OVER THE
OK/TX PANHANDLES AND FAR SWRN KS.  FORECAST SOUNDINGS INDICATE
MODEST SURFACE-BASED INSTABILITY BY 00Z ACROSS THIS REGION ALONG WRN
EDGE OF H7 THERMAL RIDGE...EVEN BEHIND CURRENT COLD FRONT...WITH 40+
KT EFFECTIVE SHEAR SUPPORTING HIGH-BASED SUPERCELLS.  THIS ACTIVITY
WILL LIKELY BECOME MORE INTENSE AS IT SPREADS INTO RICHER MOISTURE
ACROSS WRN OK/ERN TX PANHANDLE WRAPPING AROUND LOW CENTER ALONG THE
RED RIVER.  STORMS SHOULD EVOLVE INTO A LARGE COMPLEX WITH VERY
LARGE HAIL AND DAMAGING WINDS EWD ACROSS MUCH OF OK THROUGH THE
EVENING.  SHOULD ERN OK REMAIN CONVECTIVE-FREE...A VERY MOIST AIR
MASS WILL SUPPORT EXTREME INSTABILITY THROUGH THE NIGHT INTO WRN AR.
 GFS DEEPENS A LOW CENTER FROM SOUTH OF ADM BY 03Z AND LIFTS IT NEWD
INTO NWRN AR OVERNIGHT WITH SUBSEQUENT INCREASE IN SLY LLJ INTO ERN
OK.  THIS MAY SUPPORT A WIDESPREAD SEVERE THREAT FROM S-CENTRAL/SERN
OK INTO THE OZARK REGION LATER TONIGHT INCLUDING AN INCREASED
TORNADO THREAT SHOULD PRESSURE FALLS/CONVERGENCE TAP INTO RICH
MARINE AIR.

...LA ACROSS THE CENTRAL GULF COAST STATES...
INCREASING SLY LOW LEVEL WINDS ACROSS THE CENTRAL GULF COAST ARE
EXPECTED TO LIFT WARM FRONT SLOWLY NWD TODAY AHEAD OF SHORTWAVE
TROUGH NOW MOVING ACROSS TX.  IN ADDITION...MODELS MAINTAIN 40-50 KT
WLY MID LEVEL FLOW ATOP A VERY MOIST BOUNDARY LAYER WITH SURFACE DEW
POINTS IN THE LOWER TO MID 70S.  THIS SHOULD SUPPORT INCREASE IN
CONVECTION THROUGH THE LATE MORNING/AFTERNOON AS HEATING PRODUCES A
VERY UNSTABLE AIR MASS.  RUC FORECAST SOUNDINGS BECOME VERY
FAVORABLE FOR INTENSE SUPERCELLS BY LATE THIS AFTERNOON...THOUGH NAM
AND GFS PRODUCE WEAKER H85 WINDS AND LESS SHEAR TODAY.
REGARDLESS...EXPECT THREATS FOR SUPERCELLS AND MULTICELL CLUSTERS
WILL INCREASE ACROSS THE LOWER MS RIVER VALLEY AND SPREAD/DEVELOP
EWD ALONG AND NORTH OF WARM FRONT ACROSS SRN/CENTRAL MS AND SRN/WRN
AL TODAY.  LARGE HAIL AND DAMAGING WINDS WILL BE PRIMARY SEVERE
THREATS...WITH TORNADO POTENTIAL BEING STRONGER SHOULD RUC FORECASTS
VERIFY.

..EVANS/JEWELL.. 05/09/2006