Severe Thunderstorm Warning 288, NWS Fort Worth, TX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
930 AM CDT THU AUG 4 2005

.UPDATE...
MORNING UPPER AIR DATA REVEALS SOME INTERESTING FEATURES IN PLACE
ACROSS THE REGION.  FIRST...A WEAK ELEVATED SYNOPTIC BOUNDARY WHICH
EXTENDS FROM OFF THE COAST OF LOUISIANA NW TOWARD ABILENE IS
ENHANCING MOISTURE POOLING AND THIS IS WHERE AN AXIS OF NEARLY 2
INCH PRECIPITABLE WATER IS LOCATED.  SECONDLY...200 AND 250 MB
ANALYSIS SUGGEST THAT NORTH TEXAS IS CURRENTLY LOCATED IN A WEAK
DEFORMATION ZONE WHICH WILL ENHANCE UPPER LEVEL DIVERGENCE TODAY.
12Z FWD SOUNDING IS DEPICTING A SATURATED COLUMN AND VERY WEAK WINDS
THROUGH THE LOWER TROPOSPHERIC COLUMN.  ALL OF THESE PARAMETERS
CREATE AN ENVIRONMENT CONDUCIVE FOR THE DEVELOPMENT OF SCATTERED
AIRMASS CONVECTION ONCE CONVECTIVE TEMPS IN THE LOWER 90S ARE
REACHED.  HAVE INCREASED POPS TO CHANCE FOR THE SW 2/3RDS OF CWA
WHERE BEST MOISTURE IS LOCATED PER GOES SOUNDER.  WATER VAPOR LOOP
SUGGESTS THE NE CWA WILL BE IN AN AREA OF IMPINGING SUBSIDENCE AND
LEFT SLIGHT CHANCE POPS IN PLACE.  HAVE ALSO AMENDED SKY GRIDS AND
LOWERED TEMPS A COUPLE DEGREES IN THE SOUTH.   TR/92

&&

.AVIATION...
WE WILL PRIMARILY USE PERSISTENCE FOR THIS FORECAST...WITH NO
SIGNIFICANT CHANGES FROM THE PREVIOUS SET OF TAFS.  ISOLATED AND
HIGH-BASED LIGHT SHOWERS HAVE ALREADY DEVELOPED IN THE VERY MOIST
ENVIRONMENT ACROSS NORTH TEXAS...AND DECIDED TO USE VSCH THROUGH
04/16Z.  HOWEVER...CHANCES FOR A THUNDERSTORM AT ANY ONE OF THE
AIRPORTS LOOKS TOO SLIM TO MENTION...AND WILL MAINTAIN MENTION OF CB
INSTEAD.  OTHERWISE...EXPECT ANY REMAINING ACTIVITY TO DIMINISH
AROUND 05/03-04Z.  LIGHT SOUTHEAST SURFACE FLOW CAN BE EXPECTED
THROUGH THE PERIOD.

65/DD

&&

.DISCUSSION...
NOT A LOT OF CHANGES TAKING PLACE IN THE ATMOSPHERE ACROSS N TEXAS
TODAY...AS ETA FORECAST CAPE AGAIN 800-1500 J/KG WITH VIRTUALLY NO
CIN. DIFFERENCE TODAY IS ETA DOES NOT INDICATE ANY SHORT WAVE TO
WORK ACROSS THE ATMOSPHERE. THIS SUGGESTS THERE SHOULD BE A BIT
LESS CONVECTION TODAY...BUT STILL ENOUGH TO WARRANT 20 POPS ACROSS
THE CWA. ONCE AGAIN...AN ISOLATED SEVERE STORM CAN NOT BE RULED
OUT WITH INVERTED-V SOUNDING SUGGESTING WIND GUSTS FROM 50 TO 60
MPH POSSIBLE. STORMS THAT FORM SHOULD DISSIPATE IN THE EVENING
HOURS.

THINGS GET A BIT MORE INTERESTING FRIDAY INTO SATURDAY AS ETA AND
GFS NOW BRING THE COLD FRONT...OR AT LEAST SOME OUTFLOW...FURTHER
SOUTH INTO AT LEAST THE HALF OF N TEXAS. CONVERGENCE STILL LOOKS
WEAK WITH THE BOUNDARY...SO IT IS REASONABLE...AS INDICATED BY ETA
AND NAM...THAT MOST OF THE PRECIP WILL BE POST FRONTAL ACROSS OK.
WE WILL INCREASE THE POPS AND LOWER MAX TEMPS A FEW
DEGREES...ESPECIALLY ACROSS THE NRN HALF OF N TEXAS ON FRIDAY.
COULD SEE SOME LINGERING STORMS ON SAT AS FRONT WASHES OUT/RETURNS
NE...BUT MOST OF THE CONVECTION WILL LIKELY END BY LATE AFTERNOON.

STILL LOOKS LIKE SOME CHANCE OF MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH MID WEEK AS NW
FLOW AND UNSTABLE AIRMASS REMAINS IN PLACE. GFS CONTINUES TO
ADVERTISE HIGH ACROSS THE SE STATES TO BUILD NW INTO N TEXAS LATE
IN THE WEEK AND THIS SHOULD KEEP THE HEAT ON THROUGH THE MIDDLE OF
AUGUST. THE NORMAL DAILY HIGH TEMPERATURE FOR DFW BEGINS TO DROP
FROM 96 TO 95 ON THE 14TH OF AUGUST. WACO DROPS FROM 98 TO 97 ON
THE 14TH.

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  99  76  94  76 /  20  20  50  30
WACO, TX              98  74  98  74 /  20  20  40  30
PARIS, TX             97  72  92  72 /  20  20  50  30
DENTON, TX            99  74  92  74 /  20  20  50  30
MCKINNEY, TX          99  74  93  74 /  20  20  50  30
DALLAS, TX            99  79  94  77 /  20  20  50  30
TERRELL, TX           98  73  96  74 /  20  20  40  30
CORSICANA, TX         97  73  98  74 /  20  20  40  30
TEMPLE, TX            97  73  99  74 /  20  20  40  30

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
TX...NONE.

&&

/

HAZARDOUS WEATHER OUTLOOK FOR NORTH TEXAS
NATIONAL WEATHER SERVICE FORT WORTH TX
1150 AM CDT THU AUG 4 2005

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-042045-
ANDERSON-BELL-BOSQUE-COLLIN-COMANCHE-COOKE-CORYELL-DALLAS-DELTA-
DENTON-EASTLAND-ELLIS-ERATH-FALLS-FANNIN-FREESTONE-GRAYSON-HAMILTON-
HENDERSON-HILL-HOOD-HOPKINS-HUNT-JACK-JOHNSON-KAUFMAN-LAMAR-LAMPASAS-
LEON-LIMESTONE-MCLENNAN-MILAM-MILLS-MONTAGUE-NAVARRO-PALO PINTO-
PARKER-RAINS-ROBERTSON-ROCKWALL-SOMERVELL-STEPHENS-TARRANT-VAN ZANDT-
WISE-YOUNG-
1150 AM CDT THU AUG 4 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...
ISOLATED SEVERE STORMS ARE POSSIBLE THROUGH SUNSET...MAINLY
ALONG AND SOUTH OF THE INTERSTATE 20 CORRIDOR. MAIN THREATS WILL
BE WIND GUSTS TO 60 MPH...DIME SIZE HAIL...FREQUENT LIGHTNING
AND LOCALIZED...TORRENTIAL RAINFALL IN EXCESS OF 2 INCHES OR MORE.

OTHERWISE...SCATTERED SHOWERS AND STORMS WILL OCCUR JUST ABOUT
ANYWHERE OVER NORTH TEXAS THROUGH MID EVENING...WITH WIND GUSTS TO 45
MPH...LOCALLY HEAVY RAINFALL IN EXCESS OF 1 INCH...CLOUD TO GROUND
LIGHTNING...AND POSSIBLY PEA SIZED HAIL BEING THE MAIN HAZARDS.

.DAYS TWO THROUGH SEVEN...
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY AND WEDNESDAY
EVENING ACROSS ALL OF NORTH TEXAS. ON THURSDAY AFTERNOON AND
EVENING...THERE IS A SLIGHT CHANCE OF THUNDERSTORMS...SOUTH OF AN
EASTLAND...CLEBURNE...ATHENS LINE. FINALLY...THERE IS A SLIGHT
CHANCE OF THUNDERSTORMS ACROSS ALL OF NORTH TEXAS FRIDAY AND
SATURDAY...AS A WEAK COOL FRONT MOVES INTO THE AREA.

.SPOTTER INFORMATION STATEMENT...
LIMITED SPOTTER ACTIVATION MAY BE REQUESTED THROUGH 7 PM...GENERALLY
SOUTH OF THE INTERSTATE 20 CORRIDOR.