[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 181622
SWODY1
SPC AC 181620

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1120 AM CDT TUE APR 18 2006

VALID 181630Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF MO...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO RIVER VALLEY
INTO CENTRAL TX AND ERN AL/WRN GA....

...MID MO RIVER VALLEY INTO THE LOWER OH RIVER VALLEY...
SURFACE LOW WAS LOCATED OVER NEB NEAR BIE AT 16Z WITH SEWD EXTENDING
WARM FRONT STILL TAKING SHAPE ALONG THE LOWER MO RIVER VALLEY. COLD
FRONT TRAILING THE LOW CENTER WAS ADVANCING QUICKLY SEWD ACROSS
CENTRAL KS/NWRN OK...AND WILL CONTINUE INTO THE OZARKS/WRN MO BY THE
LATE AFTERNOON.  MODELS ARE FAIRLY CONSISTENT WITH SURFACE FEATURES
TODAY...DEVELOPING A LOW CENTER SEWD ALONG THE TRIPLE POINT INTO
NWRN/CENTRAL MO BY 00Z AND INTO FAR WRN KY BY THE END OF THE PERIOD.
 LOW LEVEL MOISTURE FIELDS ARE MUCH HIGHER TODAY THAN WITH THE PAST
SEVERAL SYSTEMS /I.E. H85 DEW POINTS AOA 10C AND SURFACE DEW POINTS
IN THE MID 60S F OVER ERN OK/AR /.  EXPECT MID/UPPER 60F SURFACE DEW
POINTS WILL SURVIVE MIXING WITH AN AXIS EXTENDING INTO NWRN/CENTRAL
MO BY THE LATE AFTERNOON.  UNLIKE THE PREVIOUS SEVERE WEATHER EVENTS
OVER THE PAST FEW WEEKS...LARGE SCALE ASCENT WILL NOT BECOME
MAXIMIZED INTO THE WARM SECTOR TODAY AS OF NOSE STRONG MID/UPPER
LEVEL JET LAGS WWD BEHIND THE SURFACE COLD FRONT.  HOWEVER...VERY
STEEP LAPSE RATES AND UNSEASONABLY WARM/MOIST BOUNDARY LAYER WILL
SUPPORT A STRONGLY UNSTABLE WARM SECTOR BY THE MID AFTERNOON.  IN
ADDITION...SURFACE CONVERGENCE WILL BECOME MAXIMIZED INTO THE LOWER
MO RIVER VALLEY AS TRIPLE POINT DEVELOPS SEWD. GIVEN THE MORE
LIMITED LARGE SCALE ASCENT TODAY...EXPECT HEATING AND CONVERGENCE
WILL BE NEEDED TO BREAK STRONG CAP WITH THUNDERSTORM DEVELOPMENT
POSSIBLY DELAYED UNTIL LATE IN THE DAY.  EXCEPTION WILL BE INTO IA
WHERE STRONGER FORCING WILL OVERSPREAD MARGINAL...ELEVATED
INSTABILITY NORTH OF THE WARM FRONT TODAY.  HERE...THUNDERSTORMS
SHOULD INCREASE AND SPREAD A THREAT OF LARGE HAIL NNEWD INTO THE
EVENING.

MODELS ARE MOST CONSISTENT WITH DEVELOPING PRIMARY SEVERE THREAT
BETWEEN 21Z-00Z NEAR THE LOW CENTER OVER NWRN MO AND ALONG COLD
FRONT INTO PORTIONS OF SWRN/S-CENTRAL MO.  ACTIVITY WILL INCREASE IN
SEVERITY AND COVERAGE AS STRONGEST ASCENT FINALLY CATCHES UP WITH
THE WARM SECTOR INTO THE MID MS/LOWER OH RIVER VALLEYS THROUGH THE
EVENING.  DEEP LAYER SHEAR IS NOT FORECAST TO BE OVERLY IMPRESSIVE
/35-45 KT OF SFC-6 KM SHEAR/ THOUGH WILL STILL BE ADEQUATE FOR
SUPERCELLS GIVEN AMOUNT OF INSTABILITY AND STRONG PRESSURE FALLS
AHEAD OF APPROACHING UPPER LOW/WARM FRONT.  BACKED SURFACE WINDS
SHOULD SUPPORT 0-1 KM SRH IN EXCESS OF 150 M2/S2 WITH AN INCREASED
THREAT OF TORNADOES THROUGH THE EVENING OVER CENTRAL AND SERN MO. 
EXPECT DEVELOPMENT WILL BUILD/ORGANIZE INTO A MCS WHICH MAY
CONSOLIDATE SUFFICIENTLY INTO A BOW ECHO/QUASI-LINEAR SYSTEM RACING
SEWD ALONG THE WARM FRONT INTO THE MID SOUTH/LOWER OH RIVER VALLEY
AFTER DARK. WIND DAMAGE MIGHT BECOME PREVALENT WITH THIS
ACTIVITY...THOUGH A TORNADO THREAT WILL ALSO REMAIN AS STRONG
PRESSURE FALLS PRECEDE THIS ACTIVITY.  MCS MAY CONTINUE ESEWD ACROSS
THE TN VALLEY LATER TODAY. 

...FAR ERN OK/AR INTO CENTRAL TX...
THUNDERSTORM DEVELOPMENT WILL BE MORE ISOLATED ALONG THE COLD FRONT
GIVEN STRENGTH OF CAPPING TODAY.  HOWEVER...AIR MASS WILL BECOME
MODERATELY UNSTABLE AND REMAIN UNDER MODEST WLY MID LEVEL FLOW FOR
35-45 KT OF EFFECTIVE BULK-SHEAR.  CINH WILL WEAKEN  LATER THIS
AFTERNOON AS HIGH TEMPERATURES REACH WELL INTO 90S F.
THUS...CONVERGENCE ALONG COLD FRONT AND AMOUNT OF SHEAR WILL BE
CAPABLE OF SUPPORTING ISOLATED SEVERE THUNDERSTORMS INTO THE
EARLY/MID EVENING FROM CENTRAL TX INTO WRN/CENTRAL AR.

...TN RIVER VALLEY INTO SERN AL/SWRN GA...
SURFACE FRONT WILL STALL IN A NNW-SSE ORIENTATION FROM THE ERN FL
PANHANDLE INTO MIDDLE TN.  STRONG AFTERNOON HEATING AND PRESENCE OF
UPPER 60F SURFACE DEW POINTS SHOULD SUPPORT A VERY UNSTABLE AIR MASS
WEST OF THIS FRONT.  IN ADDITION...NWLY FLOW ALOFT WILL REMAIN
SUFFICIENT FOR 30-40 KT OF DEEP LAYER SHEAR PARALLELING THE STALLED
SURFACE FRONT. REGION WILL REMAIN UNDER/AHEAD OF SHORTWAVE RIDGING
ALOFT AND LIMIT THUNDERSTORM POTENTIAL/COVERAGE ALONG THE FRONT. 
HOWEVER...FORECAST SOUNDINGS REMAIN MORE THAN SUFFICIENT FOR
ORGANIZED MULTICELLS AND ISOLATED SUPERCELLS SHOULD 
HEATING/CONVERGENCE INITIATE STORMS.  ANY SEVERE THREAT EXPECTED TO
BE DIURNALLY-DRIVEN AND DIMINISH BY THE MID EVENING.

..EVANS/CROSBIE.. 04/18/2006