Severe Thunderstorm Warning 150, NWS Shreveport, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
255 AM CDT SUN APR 23 2000

MID/UPPER LEVEL SYSTEM MOVING ACROSS OK TODAY LOOKS AS IF IT WILL
RESULT IN AN ACTIVE DAY CONVECTION-WISE ACROSS THE AREA TODAY. SFC
LOW ACCOMPANYING THE SYSTEM IS CURRENTLY NEAR LBL...AND IS FORECAST
TO MOVE SEWD TODAY...REACHING TXK BY 24/00Z AND THEN EJECTING
QUICKLY NE OVERNIGHT TONIGHT. THE COMBINATION OF SFC HEATING...WHICH
SHOULD BE STRONG AFTER MORNING CLOUDINESS BREAKS UP...AND CONVERGENCE
INTO THE APPROACHING SFC LOW SHOULD INITIATE CONVECTION THIS
AFTERNOON IN NE TX/SE OK. THE WARM SECTOR SHOULD BECOME
MODERATELY TO VERY UNSTABLE TODAY WITH SBCAPES OF 2500 TO 3000 J/KG
AND LIS OF -6 TO -8C. ALSO...WIND PROFILES ARE FORECAST TO BE
FAVORABLE FOR ORGANIZED ROTATING UPDRAFTS. FORECAST HODOGRAPHS FOR
THIS AFTERNOON ARE LONG AND EXHIBIT LITTLE WEAKNESS IN SR WINDS...
SO THE POTENTIAL FOR TORNADIC SUPERCELLS EXISTS /SEE SPC DAY1 SEVERE
OUTLOOK/. WILL DEFINITELY INCLUDE SVR WORDING ALL ZONES. WILL
PROBABLY GO WITH 50 OR 60 POPS ACROSS THE NORTH...TO 30 OR 40 PCT IN
THE SOUTH FOR TODAY. FRONT IS SUPPOSED TO BE NEAR SHV BY AROUND
06Z...SO WILL HAVE TO CONTINUE POPS INTO TONIGHT...BUT WILL INDICATE
RAIN ENDING LATE. MONDAY LOOKS LIKE IT WILL BE MAINLY DRY ACROSS THE
AREA.

WILL GO WITH MAXES TODAY NEAR OR JUST A BIT BELOW FWC GUIDANCE. FWC
LOOKS A BIT WARM ON MONDAY. 850 TEMPS ARE FORECAST BY THE ETA TO COOL
TO ABOUT 11C AT SHV MONDAY...SO HAVING A MAX HIGHER ON MONDAY THAN
TODAY SEEMS UNREASONABLE. WILL GO CLOSER TO FAN NUMBERS ON MONDAY.
05

PRELIMS...
SHV 81/60/80/53 5300
MLU 80/61/80/53 5500
TXK 80/60/77/53 6300
TYR 81/55/79/54 3100
LFK 83/57/83/54 3200

.SHV...NONE.

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-231500-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
650 AM CDT SUN APR 23 2000

...RISK OF SEVERE THUNDERSTORMS ACROSS THE FOUR STATES REGION
TODAY...

A STRONG UPPER LEVEL SYSTEM MOVING ACROSS OKLAHOMA TODAY WILL
ACT ON WARM...MOIST AND UNSTABLE AIR THIS AFTERNOON...TRIGGERING
STRONG TO SEVERE THUNDERSTORMS ACROSS THE AREA.

SURFACE LOW PRESSURE WAS LOCATED IN NORTHWEST OKLAHOMA THIS MORNING.
THIS FEATURE WILL BE MOVING SOUTHEAST TODAY...REACHING NEAR
TEXARKANA BY EARLY EVENING. AS THE FRONT ACCOMPANYING THIS SYSTEM
MOVES INTO SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS LATE THIS
AFTERNOON...THUNDERSTORMS ARE EXPECTED TO DEVELOP RAPIDLY. GIVEN
THE INSTABILITY IN THE ATMOSPHERE...AND THE PRESENCE OF FAVORABLE
WIND SHEAR...ANY STORMS THAT DEVELOP WILL LIKELY BECOME SEVERE
QUICKLY.

THE PRESENCE OF WARM...MOIST AIR NEAR THE SURFACE AND RELATIVELY
COLD TEMPERATURES ALOFT INDICATE THAT LARGE HAIL WILL BE POSSIBLE
WITH THESE THUNDERSTORMS. DAMAGING WINDS MAY ALSO OCCUR GIVEN THE
STRENGTH OF THE WINDS JUST ABOVE THE GROUND. FURTHER...THE VEERING
OF WIND DIRECTION WITH HEIGHT...COMBINED WITH INCREASING WIND
SPEEDS INDICATE A POTENTIAL FOR STORMS TO ROTATE...AND PERHAPS
PRODUCE TORNADOES.

THE GREATEST THREAT FOR SEVERE THUNDERSTORMS APPEARS AT THIS TIME
TO BE GENERALLY ALONG AND NORTH OF INTERSTATE 20. HOWEVER...SEVERE
WEATHER IS POSSIBLE ACROSS THE ENTIRE REGION FROM SOUTHEAST OKLAHOMA
AND EAST TEXAS...EASTWARD ACROSS NORTH LOUISIANA AND SOUTH ARKANSAS.

ALL PERSONS ACROSS THE FOUR STATES REGION SHOULD STAY ABREAST OF
WEATHER CONDITIONS TODAY...AND BE PREPARED TO TAKE ACTION SHOULD
SEVERE WEATHER THREATEN. EMERGENCY MANAGERS AND STORM SPOTTERS
SHOULD BE PREPARED FOR ACTIVATION LATER THIS AFTERNOON.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
730 AM CDT SUN APR 23 2000

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....PARISH/COUNTY LOCATION....

0130 AM    5 NW MAGNOLIA             AR   WIND DAMAGE
04/23/00   COLUMBIA                       2 TREES DOWNED ON HWY 344
                                          ACROSS POWERLINES. REPORTED
                                          BY LAW ENFORCEMENT.

13

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-231630-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
930 AM CDT SUN APR 23 2000

...RISK OF SEVERE THUNDERSTORMS...AND POSSIBLY TORNADOES...ACROSS
   THE FOUR STATE REGION TODAY AND TONIGHT...

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST
OKLAHOMA...SOUTHERN ARKANSAS...AND THOSE PORTIONS OF NORTHEAST TEXAS
AND NORTHERN LOUISIANA ALONG AND NORTH OF INTERSTATE 20. THERE IS A
SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTH OF INTERSTATE 20.

A STRONG UPPER LEVEL SYSTEM AND AN ASSOCIATED SURFACE FRONT WILL
MOVE INTO SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS LATER THIS
AFTERNOON...AND INTO ARKANSAS AND LOUISIANA TONIGHT. THESE FEATURES
WILL ACT UPON WARM...MOIST AND UNSTABLE GULF AIR WHICH IS FLOWING
INTO THE REGION AHEAD OF THE FRONT...TRIGGERING STRONG TO SEVERE
THUNDERSTORMS ACROSS THE AREA. LARGE HAIL AND STRONG WINDS ARE
LIKELY WITH THE STRONGEST STORMS. FURTHERMORE...WIND SHEAR PATTERNS
IN THE LOWER TO MIDDLE TROPOSPHERE WILL PROMOTE THE DEVELOPMENT OF
LONG LIVED SUPERCELLS WHICH COULD PRODUCE TORNADOES.

ISOLATED THUNDERSTORMS WILL ALSO BE POSSIBLE DURING THE DAY AND
EVENING WELL TO THE EAST OF THE PRIMARY ACTIVITY.

ALL PERSONS ACROSS THE FOUR STATE REGION SHOULD STAY ABREAST OF
WEATHER CONDITIONS TODAY...AND BE PREPARED TO TAKE ACTION SHOULD
SEVERE WEATHER THREATEN.

THE ACTIVATION OF SEVERE THUNDERSTORM SPOTTERS...EMERGENCY MANAGEMENT
PERSONNEL...HAM RADIO OPERATORS...AND SKYWARN NETWORKS WILL LIKELY BE
REQUIRED TODAY AND TONIGHT.