FXUS64 KFWD 232039
AFDFWD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
239 PM CST WED DEC 23 2009
.AVIATION UPDATE...
FOR THE 21Z TAF UPDATE...SENT OUT THE 21Z TAFS A BIT EARLY WITH
INTERMEDIATE THOUGHTS IN PLACE. BASICALLY CHANGED THE FIRST 6 HRS
TO ACCOUNT FOR EXPECTED APPROACH OF SFC LOW. EXPECT WINDS OVER TAF
SITES TO BEGIN TO BACK WITH TIME AS THE SFC LOW MOVES INTO THE
AREA FROM THE SOUTHWEST. AS THIS OCCURS EXPECT THAT SHRA AND TSRA
CHANCES WILL CREEP BACK WEST TOWARDS TAF SITES. THERE IS SOME
CHANCE FOR SVR WX TO AFFECT TAF SITES FOR THE REMAINDER OF THIS
AFTERNOON/INTO THE EVENING HRS. RUC HAS PREFRONTAL TROUGH CREEPING
SOUTHEAST BRINGING WINDS AROUND TO THE NORTHEAST FOR TARRANT
COUNTY TAF SITES AND BRINGING LIGHT AND VARIABLE CONDITIONS EAST.
THE SFC LOW LOOKS TO MOVE NORTHEAST AFT 06Z SENDING THE LEADING
EDGE OF THE COLD FRONT SOUTH AND BRINGING WINDS AROUND TO THE
NORTHWEST. STILL EXPECT RAIN TO AFFECT TAF SITES AFTER COLD FRONT
MOVES THRU AND SHOULD ALSO SEE LOWERING OF CIGS AS THE FRONT MOVES
THRU. COLDER AIR LOOKS TO MOVE INTO TAF SITES SHORTLY AFTER
SUNRISE IMPROVING CIGS BUT BRINGING STRONG NORTHWEST WINDS INTO
NORTH TX. THESE WINDS LOOK TO BECOME VERY STRONG BY THE AFTERNOON
HRS PROVIDING DANGEROUS CROSSWIND CONDITIONS FOR ANY NORTH/SOUTH
RUNWAY CONFIGS. NAM HAS WINDS VEERED A BIT MORE AROUND TO THE
NORTH THAN GFS/LAMP. FOR NOW HAVE GONE IN BETWEEN AND KEPT THINGS
AT A DIRECTION OF 300...ALTHO REALIZE THERE MAY BE A BIG
DIFFERENCE IN IMPACTS OF 290 VS 320 WIND DIRECTION...300 LOOKS TO
BE THE MOST CONSISTENT DIRECTION FROM GUIDANCE AT THIS TIME.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 229 PM CST WED DEC 23 2009/
LOTS GOING ON TODAY. THE SEVERE THREAT CONTINUES...INITIALLY EAST
OF THE INTERSTATE 35 CORRIDOR. AS A SURFACE LOW DEVELOPS IN SOUTH
TEXAS AND TRANSITIONS NORTHEAST...LOW LEVEL WINDS CAN BACK
FARTHER WEST AND THE SEVERE THREAT MAY EXPAND BACK INTO THE
INTERSTATE 35 AREA. AGAIN...HAIL IS THE MAIN THREAT BUT BACKED
LOW LEVEL WINDS MAY PROVIDE ENOUGH SHEAR FOR A TORNADO.
THE COLD FRONT SHOULD TRANSITION ACROSS NORTH TEXAS BEGINNING
LATE THIS EVENING IN THE NORTHWEST...REACHING SOUTHEAST ZONES BY
LATE MORNING. THE NORTHWEST WINDS BEHIND THIS COLD FRONT ARE
EXPECTED TO BE QUITE STRONG...AND WE HAVE ALREADY ISSUED A WIND
ADVISORY FOR THURSDAY. SUSTAINED WINDS ABOVE 30 MPH ARE
POSSIBLE...WITH GUSTS NEAR 45 MPH DURING THE AFTERNOON. THERE
WILL BE SOME SNOW IN NORTHWEST COUNTIES THURSDAY MORNING...BUT
WITH WARM GROUND TEMPERATURES WE DO NOT SEE MUCH ACCUMULATION.
AGAIN...SHOULD THE UPPER LOW TRACK END UP FARTHER SOUTH...THE
SNOW PATTERN WILL CHANGE ALONG WITH IT. ALL PRECIPITATION SHOULD
END ON THURSDAY AS THE UPPER LOW FINALLY PULLS OUT INTO THE MID
MISSISSIPPI VALLEY.
PER THE 12Z GFS...THIS SYSTEM HAS 500MB HEIGHTS...STANDARDIZED
ANOMALIES...MORE THAN 3 STANDARD DEVIATIONS BELOW THE AVERAGES.
THESE STRONG SYSTEMS ARE RARE...AND THUS THE ESTIMATES OF A
COUPLE OF FEET OF SNOW IN THE NORTHERN PLAINS...THE STRONG WINDS
IN TEXAS...AND THE UNSEASONABLY WARM TEMPERATURES TODAY FOLLOWED
BY UNSEASONABLY COLD TEMPERATURES TOMORROW. WIND CHILLS IN THE
TEENS ARE EXPECTED THURSDAY AND FRIDAY MORNINGS.
IN THE EXTENDED...NORTH TEXAS REMAINS COOL AND DRY UNTIL THE NEXT
SYSTEM MOVES INTO THE AREA AROUND TUESDAY. HAVE KEPT THE LOW POPS
MONDAY AFTERNOON THROUGH DAY 7 UNTIL WE GET A BETTER HANDLE ON
THE TIMING. 84
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 41 44 25 43 28 / 90 50 5 5 5
WACO, TX 44 50 26 47 27 / 80 20 5 5 5
PARIS, TX 43 45 23 38 25 / 90 80 20 5 5
DENTON, TX 38 41 22 41 25 / 90 60 10 5 5
MCKINNEY, TX 38 44 22 41 24 / 90 60 10 5 5
DALLAS, TX 41 45 25 42 28 / 90 50 10 5 5
TERRELL, TX 46 46 26 43 27 / 90 50 10 5 5
CORSICANA, TX 47 50 27 44 27 / 90 40 5 5 5
TEMPLE, TX 47 51 28 47 29 / 80 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 8 AM TO 9 PM CST THURSDAY FOR TXZ091>095-
100>107-115>123-129>135-141>148-156>162-174-175.
&&
$$
