Severe Thunderstorm Warning 41, NWS Fort Worth, TX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
736 PM CST THU FEB 26 2009

.UPDATE...
DRYLINE HAS BEGUN RETREATING. WINDS AT GAINESVILLE AND DECATUR
SHIFTED FROM WEST TO SOUTH WITH DRAMATIC CHANGE IN DEW POINTS.
GLE 90/18 TO 81/59...LUD 86/23 TO 80/55. COLD FRONT IS NOW THROUGH
GAINESVILLE AND GRAHAM. CONVECTION ALONG FRONT IS CURRENTLY
CONFINED TO OKLAHOMA...BUT TOWERS ARE GOING UP IN GRAYSON COUNTY.
NEAR SUNSET...A FEW CELLS (WITH A BIT OF IN-CLOUD LIGHTNING)...
DEVELOPED ACROSS TARRANT COUNTY...WHERE MIXED-LAYER CAPE VALUES
WERE OVER 1500 J/KG. FWD 00Z RAOB SHOWED CAP HAD COOLED SLIGHTLY
SINCE 12Z AND WAS NEGLIGIBLE NEAR PEAK HEATING. MOISTURE REMAINS
RATHER SHALLOW...AND WINDOW FOR THERMODYNAMIC CONQUERING OF
INHIBITION APPEARS TO BE CLOSED. NONETHELESS...NEAR-BOUNDARY
MECHANICAL LIFTING MAY AID IN UPDRAFT INITIATION THIS EVENING AND
OVERNIGHT AS BOUNDARY ENCOUNTERS DEEPER MOISTURE TO THE EAST.
AREA OF CONCERN FOR STRONG/SEVERE CONVECTION REMAINS...AND SEVERE
THREAT WILL CONTINUE TO BE MONITORED AS THE EVENING PROGRESSES.

25

&&

.AVIATION...
/00Z UPDATE/

VFR CONDITIONS PREVAILING ACROSS NORTH TEXAS ATTM...BUT AWAITING
PASSAGE OF COLD FRONT ALONG WITH INCREASED LOW CLOUDINESS AND SOME
SCATTERED SHOWER AND TSTM ACTIVITY. COLD FRONT IS CURRENTLY
LOCATED ACROSS SOUTH CENTRAL OKLAHOMA AND WILL BE SLOW TO SLIDE
SOUTHWARD OVERNIGHT. WILL SEE A GRADUAL POOLING OF MOISTURE AHEAD
OF THE FRONT WHICH WILL RESULT IN MVFR CIGS DEVELOPING SOMETIME
AFTER MIDNIGHT AT THE MAJOR AIRPORTS. THUNDERSTORM ACTIVITY SHOULD
REMAIN TO THE NORTHEAST OF THE AIRPORTS BUT MAY HAVE TO CONTEND
WITH SOME SHOWERS IN THE VICINITY. OTHERWISE...WILL PREVAIL MVFR
CIGS AFTER 9Z IN THE METROPLEX AND THESE LOW CLOUDS SHOULD STICK
AROUND FOR THE BETTER PART OF FRIDAY. WILL SHOW WINDS SHIFTING TO
THE NORTH DURING THE EARLY MORNING HOURS FRIDAY. IMPROVING
CONDITIONS EXPECTED LATE IN THE PERIOD WITH VFR CONDS LATE FRIDAY
NIGHT INTO SATURDAY.

91/DUNN

&&

.PREV DISCUSSION... /ISSUED 236 PM CST THU FEB 26 2009/
SURFACE COLD FRONT IS NOW LOCATED FROM ROUGHLY MANHATTAN KANSAS TO
LAWTON OKLAHOMA AND INTO OUR NORTHWESTERN COUNTIES. DRY LINE IS LOCATED
ACROSS OUR WESTERN COUNTIES...WHERE DEWPOINTS HAVE DROPPED INTO
THE 20S AND TEMPS HAVE SOARED INTO THE LOWER 90S.

OUR NORTHEASTERN COUNTIES REMAIN UNDER A SLIGHT RISK OF SEVERE
STORMS TONIGHT AS COLD FRONT TRANSLATES ACROSS THE REGION.
ENVIRONMENT SHOULD REMAIN CAPPED UNTIL LATE THIS EVENING OR EVEN
AFTER MIDNIGHT. WINDOW FOR A MARGINAL SEVERE STORM OR TWO WILL BE
BRIEF. BULK SHEAR AROUND 30KTS...MID LEVEL LAPSE RATES OF 7-8C/KM
AND 1000J/KG OR MORE OF INSTABILITY WILL BE SUFFICIENT TO ALLOW
FOR ANY ROGUE STORM TO BRIEFLY BECOME SEVERE. NICKEL TO QUARTER
SIZE HAIL AND GUSTY WINDS WILL BE THE MAIN HAZARDS ASSOCIATED WITH
ANY STORMS.

HIGH TEMPERATURES TOMORROW BEHIND THE COLD FRONT WILL BE 20 TO 30
DEGREES COLDER THAN TODAY. TEMPS SHOULD TOP OUT IN THE 50S AND 60S
OVER THE NORTHERN HALF OF THE AREA...WITH MID TO UPPER 70S FOR
CENTRAL TEXAS.

UPPER CYCLONE NOW OVER WASHINGTON/IDAHO WILL RIDE INTO THE MIDWEST
ON SATURDAY...BRINGING ANOTHER FRONT INTO NORTH TEXAS AND A
REINFORCING SHOT OF COOLER AND DRIER AIR. HIGHS ON SATURDAY WILL
RANGE FROM THE LOWER 50S ALONG THE RED RIVER TO THE LOWER 60S IN
OUR SOUTHERN ZONES.

DEWPOINTS ON SATURDAY WILL DROP INTO THE TEENS AND 20S...YIELDING
AFTERNOON RELATIVE HUMIDITY VALUES OF 20 TO 25 PERCENT FOR MUCH OF
THE AREA. 850MB WINDS OF 30 TO 40 KTS SHOULD EASILY MIX TO THE
SURFACE...RESULTING IN SUSTAINED NORTH WINDS FROM 15 TO 25 MPH AND
GUSTS UP TO 35. GIVEN THIS...WE HAVE ISSUED A FIRE WEATHER WATCH
FOR AREAS ALONG AND WEST OF INTERSTATE 35 ON SATURDAY. SEE THE
FIRE WEATHER WATCH AND FIRE WEATHER FORECAST FOR MORE DETAILS.

RIDGING ALOFT AND SOUTH WINDS WILL RETURN FOR THE START OF NEXT
WEEK...ALLOWING FOR A GRADUAL WARM UP IN THE EXTENDED FORECAST.

SCHULTZ

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  58  62  38  57  28 /  10  10  10   5   0
WACO, TX              63  71  45  62  31 /   5  10   5   5   0
PARIS, TX             57  61  39  55  27 /  30  30  10   5   0
DENTON, TX            54  59  38  56  27 /  10  10  10   5   0
MCKINNEY, TX          56  58  39  55  26 /  20  10  10   5   0
DALLAS, TX            59  62  42  57  30 /  10  10  10   5   0
TERRELL, TX           62  64  41  57  29 /  10  10  10   5   0
CORSICANA, TX         64  69  42  59  30 /  10  10  10   5   0
TEMPLE, TX            62  74  47  61  29 /   5   5   5   0   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR TXZ091-092-100>103-115>119-129>134-141>145-156>160-
174.

&&

91/25

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
709 PM CST THU FEB 26 2009

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-271100-
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-
709 PM CST THU FEB 26 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...TONIGHT.

WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP SOUTHWEST
ALONG A SLOW-MOVING COLD FRONT AND WILL AFFECT AREAS MAINLY NORTH
AND EAST OF A GAINESVILLE TO GRANBURY TO PALESTINE LINE TONIGHT.
A FEW OF THESE STORMS COULD BECOME MARGINALLY SEVERE WITH LARGE
HAIL AND STRONG WINDS. FREQUENT CLOUD TO GROUND LIGHTNING IS ALSO
LIKELY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A FIRE WEATHER WATCH IS IN EFFECT FOR SATURDAY AFTERNOON AND EARLY
EVENING ACROSS AREAS ALONG WEST OF INTERSTATE 35...WHILE AN
ELEVATED TO HIGH GRASS FIRE DANGER MAY OCCUR FURTHER ACROSS
EASTERN NORTH TEXAS.

AN ELEVATED GRASS FIRE DANGER RISK MAY RETURN TO WESTERN SECTIONS OF
NORTH TEXAS AGAIN ON MONDAY...AS WARMING TEMPERATURES COMBINE WITH
DRY CONDITIONS AND THE RETURN OF BRISK SOUTHERLY WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUESTED MAINLY ACROSS THE NORTHEAST
QUADRANT OF NORTH TEXAS THROUGH THE OVERNIGHT HOURS.

05/91