FXUS64 KFWD 240524
AFDFWD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
1124 PM CST WED DEC 23 2009
.AVIATION...
COLD FRONT HAS PUSHED THROUGH MOST OF THE TAF SITES AND WILL BE
THROUGH WACO IN THE NEXT COUPLE OF HOURS. FOG HAS DEVELOPED WACO
AS THE SURFACE LOW IS MOVING THROUGH THE AREA. ONCE THE FRONT
PUSHES THROUGH...THE FOG SHOULD CLEAR OUT.
AREA OF PRECIP IS APPROACHING THE METRO TAFS FROM THE WEST AND
WILL START THE TAFS PREVAILING WITH RAIN. OCCASIONAL STROKES OF
LIGHTNING ARE EMBEDDED IN THE INITIAL BAND OF PRECIP AND WILL
TEMPO TSRA THROUGH 9Z. CIGS HAVE BEGUN TO DROP AND EXPECT THEM TO
BE AROUND 1-2KFT THROUGH THE NIGHT AND TOMORROW AS STRONG WINDS ON
THE SURFACE KEEPS THE BOUNDARY LAYER MIXED.
MODELS ARE STILL INDICATING THE ATMOSPHERIC THERMAL PROFILE WILL
BE CAPABLE OF SUPPORTING SNOW FOR THE METROPLEX BEGINNING AT 15Z
THURSDAY. SNOW WILL LINGER ON THE BACKSIDE OF THE UPPER LOW
PRESSURE SYSTEM THROUGH AROUND 22Z.
WIND SPEEDS WILL BE PROBLEMATIC TOMORROW BEHIND THE FRONT. WIND
SPEEDS IN THE AFTERNOON WILL BE SUSTAINED AROUND 27 KNOTS WITH
GUST UP TO 40 KNOTS. NEW MODEL GUIDANCE SUGGEST A MORE NW
COMPONENT THAN WNW AND THAT WILL HELP ALLEVIATE CROSSWIND
PROBLEMS...BUT GIVEN THE SNOWFALL...VISIBILITIES MAY BE GREATLY
REDUCED.
85/NH
&&
.UPDATE...
00Z MODEL GUIDANCE FOLLOWS THE TRENDS OF VERY AGGRESSIVE 18Z RUNS
SO HAVE MADE SOME SIGNIFICANT CHANGES TO CURRENT FORECAST. HAVE
ISSUED A WINTER STORM WARNING FOR NORTHWEST PORTIONS OF N TX WITH
A WINTER WX ADVISORY A LITTLE FARTHER SOUTH. SEE WSWFWD FOR LATEST
INFORMATION.
POWERFUL UPPER LEVEL STORM SYSTEM CONTINUES TO BE A LITTLE SLOWER
THAN PREVIOUS MODEL GUIDANCE INDICATIONS WITH COLDER AIR NOW MORE
LIKELY TO MAKE IT INTO NORTH TEXAS BEFORE MOISTURE PULLS OFF TO
THE EAST. ALL OF THE GUIDANCE INDICATES SIGNIFICANT WRAP AROUND
MOISTURE COINCIDING WITH MODERATE LIFT IN THE 700-400MB LAYER...
WITH SATURATION IN THE FAVORABLE AREA FOR SNOW PRODUCTION.
ALTHOUGH INDICATIONS ARE THAT INSTABILITY IS NOT QUITE AS
IMPRESSIVE ABOVE THE STRONGEST FRONTOGENETIC FORCING AS WE WOULD
LIKE IT TO BE...SNOW IS STILL LIKELY. THE COMBINATION OF SNOW AND
STRONG WINDS WILL CREATE NEAR BLIZZARD CONDITIONS AT TIMES...THEREFORE
WARRANTING A WARNING. WITH AIR TEMPS JUST ABOVE FREEZING AND SOIL
TEMPS QUITE WARM...ACCUMULATIONS ARE LIKELY TO BE LIMITED TO AREAS
WHERE SNOW BANDS SET UP.
ALSO...BUMPED UP START TIME OF WIND ADVISORY TO 12Z TO COINCIDE
WITH WINTER STORM WARNING.
91/DUNN
&&
.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 40 40 25 43 28 / 80 80 5 5 5
WACO, TX 45 45 26 47 27 / 80 30 5 5 5
PARIS, TX 41 41 23 38 25 / 80 90 20 5 5
DENTON, TX 38 38 22 41 25 / 80 90 10 5 5
MCKINNEY, TX 39 39 22 41 24 / 80 90 10 5 5
DALLAS, TX 41 41 25 42 28 / 80 80 10 5 5
TERRELL, TX 45 45 26 43 27 / 80 80 10 5 5
CORSICANA, TX 48 48 27 44 27 / 80 60 5 5 5
TEMPLE, TX 46 46 28 47 29 / 80 20 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 9 AM TO 4 PM CST THURSDAY FOR
TXZ094-095-104>107-118>123-130>134-141.
WIND ADVISORY FROM 6 AM TO 9 PM CST THURSDAY FOR TXZ091>095-
100>107-115>123-129>135-141>148-156>162-174-175.
WINTER STORM WARNING FROM 6 AM TO 4 PM CST THURSDAY FOR
TXZ091>093-100>103-115>117-129.
&&
$$
85/82
