ZCZC MKCSWODY1 000
ACUS1 KMKC 231858
MKC AC 231858

CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O.

VALID 231900Z - 241200Z

REF WW NUMBER 0755...VALID TIL 0200Z

THERE IS A MDT RISK OF SVR TSTMS OVER EAST CENTRAL AND SOUTHEAST
TEXAS..MUCH OF CENTRAL AND SOUTHERN LOUISIANA...AND A SMALL PART OF
SOUTHWEST MISSISSIPPI.  THE AREA IS TO THE RIGHT OF A LINE FROM PSX
AUS TPL GGG HEZ MCB BVE.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
45 S VCT 15 SSE SAT BWD 20 S FTW 20 SSE PRX GWO TCL TOI PFN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 SE CRP DRT MAF
LBB AMA 15 SE GLD 10 SE SUX 20 WNW DBQ SPI 15 N DYR HSV AUO AQQ.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM PGA U24 OWY PDT EPH
3TH COD CPR CYS COS RTN ABQ GUP PGA.

...SEVERE THUNDERSTORM FORECAST DISCUSSION...

...SYNOPSIS...

AN UPPER LOW OVER NORTHWEST TEXAS WILL OPEN UP AND EJECT EAST-
NORTHEAST AS A SHORT WAVE TROUGH...REACHING THE LOWER MISSISSIPPI
RIVER VALLEY LATE IN THE PERIOD.  MEANWHILE...A STRONG UPPER JET
WILL DIG SOUTH FROM OREGON TO WESTERN NEVADA...WITH A CLOSED LOW
FORMING BY EARLY FRIDAY OVER UTAH.  LEE CYCLOGENESIS IS EXPECTED TO
OCCUR LATE TONIGHT ALONG THE COLORADO/KANSAS BORDER.   

...EAST TEXAS TO THE FLORIDA PANHANDLE...

STILL APPEARS THAT MANY OF THE INGREDIENTS ARE COMING TOGETHER FOR
A SIGNIFICANT SEVERE WEATHER EPISODE...ESPECIALLY FROM SOUTHEAST
TEXAS INTO CENTRAL/SOUTHERN LOUISIANA.

12Z ETA CONTINUES TO SHOW STRONG 500 MB WIND MAX SPREADING FROM
SOUTH TEXAS INTO THE LOUISIANA COASTAL WATERS DURING THE PERIOD. 
A 75 KNOT SPEED MAX AT 00Z IS FORECAST TO GRADUALLY WEAKEN
OVERNIGHT...BUT 50+ KNOT 500 MB FLOW IS EXPECTED TO EXTEND FROM
SOUTHEAST TEXAS TO SOUTHERN MISSISSIPPI THROUGH 06Z.  THE LOW/MID
LEVEL JETS CROSS AT NEARLY A 90 DEGREE ANGLE NEAR SOUTHERN
LOUISIANA FOR MUCH OF THE PERIOD...CREATING STRONG VERTICAL WIND
SHEAR.  FORECAST STORM RELATIVE HELICITY VALUES OF 400-700 M2/S2 IN
THE MODERATE RISK AREA SUGGEST STRONG POTENTIAL FOR SUPERCELLS
INCLUDING TORNADOES.    

STRONG PRESSURE FALLS INDICATIVE OF PERSISTENT LOW LEVEL THETA-E
ADVECTION HAVE ALLOWED DESTABILIZATION OVER THE AREA...WITH SURFACE
BASED CAPES OF 1000-2000 J/KG ALREADY IN PLACE.  SLIGHTLY HIGHER
VALUES OF INSTABILITY ARE LIKELY ALONG THE COASTAL SECTIONS DURING
THE NIGHT.  

STRONG UPPER DIVERGENCE IN THE LEFT EXIT REGION OF THE SUBTROPICAL
JET SHOULD HELP CREATE STRONG UPWARD MOTION JUST AHEAD OF THE SHORT
WAVE TROUGH AS IT MOVES EAST-NORTHEAST.  ISOLATED TORNADIC
SUPERCELLS ARE EXPECTED THROUGH THE EARLY EVENING HOURS OVER PARTS
OF EAST TEXAS...WITH ACTIVITY EVOLVING INTO A FAST MOVING SQUALL
LINE DURING THE NIGHT AS IT PUSHES ACROSS LOUISIANA INTO
MISSISSIPPI.  WIND DAMAGE WILL BECOME THE PRIMARY THREAT DURING THE
NIGHT...BUT ISOLATED EMBEDDED HP SUPERCELLS AND BOW ECHO COMMA HEAD
CIRCULATIONS COULD DEVELOP TORNADOES GIVEN HIGH HELICITY VALUES. 

..CRAVEN.. 10/23/97