Severe Thunderstorm Warning 342, NWS Fort Worth, TX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
655 PM CDT TUE SEP 18 2007

.AVIATION...
655 PM CDT

MID-LEVEL RIDGING HAS SHIFTED EAST DURING THE PAST 24 HOURS...
SETTING UP CONVEYOR BELT OVER TEXAS. INCREASED MOISTURE EVIDENT WITH
CU DEVELOPMENT TODAY. CONVECTION ON WESTERN PERIPHERY OF MOISTURE
TONGUE WILL REMAIN WELL WEST OF METROPLEX SITES.

SHRA/TSRA NOT FAR FROM WACO...MEAGER OUTFLOW HEADING TOWARD KACT BUT
SHOULD BE OF LITTLE CONSEQUENCE.

CU DEVELOPMENT SHOULD BE CONSIDERABLE AGAIN ON WEDNESDAY. WILL
MORNING MOISTURE ABOVE NOCTURNAL INVERSION...WILL CARRY PREVAILING
BKN VFR DECK FOR METRO SITES FOR BULK OF DAY. SHOULD BE ABOVE 4KFT
THRESHOLD FOR DFW ARRIVALS. 25

&&

.PREV DISCUSSION...
326 PM CDT

SHORT TERM FORECAST FOCUS WILL BE ON A LINE OF SHOWERS AND
THUNDERSTORMS TO THE WEST AND NORTHWEST OF THE CWA. AFTERNOON
00HR RUC ANALYSIS INDICATES THE LINE OF CONVECTION DEVELOPING ALONG
AN ELONGATED MID AND UPPER LEVEL SHEAR AXIS DRAPED FROM NEAR THE
KANSAS CITY AREA...TO WESTERN NORTH TEXAS...TO NEAR THE TX BIG BEND
REGION. WATER VAPOR AND REGIONAL WIND PROFILERS DEPICT A MID LEVEL
SHORTWAVE TROF AXIS EJECTING INTO THE CENTRAL PLAINS /FROM WESTERN
NEBRASKA INTO THE TEXAS PANHANDLE/.

A FEW SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN OUR WESTERN
COUNTIES THIS AFTERNOON AND EVENING. STRONGEST STORMS AND GREATEST
COVERAGE WILL BE NORTH OF THE CWA /ACROSS KANSAS/ WHERE STRONGER
DYNAMIC FORCING IS PRESENT. ACTIVITY ACROSS NORTH TEXAS IS
EXPECTED TO GENERALLY WEAKEN AFTER SUNSET...BUT WITH THE ELONGATED
SHEAR AXIS REMAINING IN THE VICINITY AND A VORT LOBE MOVING
NORTHEAST FROM THE BIG BEND AREA...A FEW SHOWERS/STORMS MAY BE
POSSIBLE OVERNIGHT. THEREFORE...HAVE INTRODUCED SLT CHC POPS FOR
OUR WESTERN AND NORTHWESTERN COUNTIES TONIGHT.

A NARROW RIBBON OF MOISTURE IS FEEDING THE CONVECTION TODAY...AND
THIS STREAM /ALONG WITH THE MID AND UPPER LEVEL SHEAR AXIS/ IS
EXPECTED TO SHIFT SLIGHTLY EAST TOMORROW. SHOWERS AND STORMS WILL
BE POSSIBLE WED AFTERNOON...GENERALLY ALONG AND WEST OF THE I-35
CORRIDOR. HOWEVER...THE FAVORABLE AREA FOR TOMORROWS CONVECTION
WILL LARGELY BE DEPENDENT ON HOW FAR EAST THE AFOREMENTIONED SHEAR
ZONE ALIGNS ITSELF. SURFACE HIGH PRESSURE AND DRIER AIR WILL BUILD
INTO THE AREA FROM THE EAST AND SHOULD PERMIT THE SHEAR ZONE FROM
DRIFTING TOO FAR EAST...AND IS EXPECTED TO EVENTUALLY HELP TO PUSH
THE AXIS NORTHWEST OF OUR FORECAST AREA.

A QUIESCENT PERIOD IS IN STORE FOR THE AREA LATE IN THE WORK WEEK
THROUGH THE EARLY PART OF THE WEEKEND. NEXT FORECAST CHALLENGE
/AND CHANCE OF PRECIP/ WILL BE TIMING AND LOCATION OF A TROPICAL
SYSTEM SET TO ORGANIZE OFF THE COAST OF FLORIDA BY THURS. TODAYS
MODEL RUNS ARE SHIFTING THE EFFECTS OF THIS SYSTEM FURTHER EAST
THAN PREVIOUSLY FORECAST. ECMWF/GFS ARE IN FAIRLY GOOD AGREEMENT
/WITH SUPPORT FROM THE CANADIAN/ OF THE TROPICAL SYSTEM IMPACTING
EAST TEXAS AND WESTERN LOUISIANA MONDAY AND TUESDAY. UNDOUBTEDLY
LOCATION AND TIMING WILL NEED TO BE REFINED...BUT FOR NOW WE HAVE
CONFINED POPS TO GENERALLY THE SOUTHEAST ONE THIRD OF THE AREA.

FOR TEMPERATURES...GENERALLY NEAR TO SLIGHTLY ABOVE NORMAL HIGHS
/LOW 90S/ AND SEASONABLE LOWS /60S AND 70S/.

SCHULTZ

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  73  92  72  91  70 /  10  10  10   0   0
WACO, TX              73  92  71  92  69 /  20  10  10   0   0
PARIS, TX             69  91  66  90  64 /  10  10  10   0   0
DENTON, TX            71  91  70  91  67 /  10  20  10   0   0
MCKINNEY, TX          69  91  69  91  66 /  10  10  10   0   0
DALLAS, TX            74  91  73  91  72 /  10  10  10   0   0
TERRELL, TX           71  91  69  91  66 /  10  10  10   0   0
CORSICANA, TX         72  92  70  91  68 /  10  10  10   0   0
TEMPLE, TX            71  92  70  92  67 /  20  10  10   0   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

58/25/82/77

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
600 PM CDT TUE SEP 18 2007

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-191100-
MONTAGUE-COOKE-GRAYSON-FANNIN-LAMAR-YOUNG-JACK-WISE-DENTON-COLLIN-
HUNT-DELTA-HOPKINS-STEPHENS-PALO PINTO-PARKER-TARRANT-DALLAS-
ROCKWALL-KAUFMAN-VAN ZANDT-RAINS-EASTLAND-ERATH-HOOD-SOMERVELL-
JOHNSON-ELLIS-HENDERSON-COMANCHE-MILLS-HAMILTON-BOSQUE-HILL-
NAVARRO-FREESTONE-ANDERSON-LAMPASAS-CORYELL-BELL-MCLENNAN-FALLS-
LIMESTONE-LEON-MILAM-ROBERTSON-
600 PM CDT TUE SEP 18 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...
ISOLATED THUNDERSTORMS ARE POSSIBLE WEST OF THE I-35 CORRIDOR
THROUGH THE EVENING HOURS. THE STRONGER STORMS WILL BE CAPABLE OF
PRODUCING HAIL AND WIND GUSTS IN EXCESS OF 50 MPH. THE STRONGEST
STORMS MAY BECOME SEVERE...WITH HAIL TO THE SIZE OF NICKELS AND
DAMAGING WINDS IN EXCESS OF 60 MPH.

.DAYS TWO THROUGH SEVEN...
ISOLATED THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE WEDNESDAY WEST
OF INTERSTATE 35. NO SEVERE WEATHER IS ANTICIPATED.

THE NEXT CHANCE FOR THUNDERSTORMS WILL BE LATE THIS WEEKEND OVER
AREAS EAST OF INTERSTATE 35...AS A TROPICAL WAVE MOVES NORTH INTO
THE UPPER TEXAS...BEFORE LIFTING NORTH ACROSS EAST TEXAS. SEVERE
THUNDERSTORMS ARE NOT EXPECTED...THOUGH LOCALLY HEAVY RAINFALL WILL
BE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUESTED THIS EVENING IN AREAS WEST OF
I-35 CORRIDOR.

05/25