Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX

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000
FXUS64 KFWD 301806
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
106 PM CDT THU OCT 30 2014

.AVIATION...
THE MAIN CONCERNS FOR THE 18 UTC TAF ISSUANCE WILL BE THE APPROACH OF
A PRE-FRONTAL TROUGH AND COLD FRONT...AS WELL AS POTENTIAL FROM
PRECIPITATION AT BOTH METROPLEX AND WACO TERMINALS.

CONCERNING THE METROPLEX TAF SITES...A FEW CLOUDS AROUND 5KFT WILL BE
POSSIBLE THIS AFTERNOON IN CONJUNCTION WITH MIXING AND THE APPROACH
OF A WEAK PRE-FRONTAL TROUGH. SHORTLY AFTER THE PASSAGE OF THE
TROUGH...WINDS WILL GRADUALLY VEER TOWARDS THE WSW. HAVE RETAINED
VCSH BASED ON SLIGHTLY AGITATED CU FIELD ALONG THE RED RIVER AND
TRENDS IN HI-RES MODEL OUTPUT. DATA FROM THE MORNING WEATHER
BALLOON...RECENT AIRCRAFT SOUNDINGS...AND IN-HOUSE THUNDERSTORM
PARAMETERS ARE NOT VERY CONDUCIVE FOR THUNDERSTORM ACTIVITY AT THIS
TIME...BUT CANNOT RULE IT OUT COMPLETELY. MORE NORTHERLY
WINDS...COMPLEMENTS OF THE TRUE COLD FRONT/WIND SHIFT...SHOULD ARRIVE
ACROSS THE MEXTROPLEX AROUND THE 23-00 UTC TIME FRAME THIS EVENING. A FEW
CLOUDS AROUND 6KFT WILL REMAIN THROUGH THE OVERNIGHT HOURS. WITH THE
COLDER AIR FILTERING IN...THINK THAT WE MAY BE TOO STABLE TO MIX
OVERNIGHT....BUT THE STIFF PRESSURE GRADIENT WILL HELP TO KEEP WINDS
UP TO 10 KNOTS. STRONGER BREEZES WILL BE POSSIBLE FRIDAY AFTER
SUNRISE AND MIXING COMMENCES. WIND GUSTS TO 25 KNOTS WILL BE POSSIBLE
THROUGH SUNDOWN FRIDAY.

CONCERNING THE WACO TAF SITE...SCT TO BKN VFR CLOUDS WILL CONTINUE
THIS AFTERNOON AS LOW LEVEL MOISTURE LIFTS AHEAD OF THE
APPROACHING FRONT. A WEAK SURFACE LOW WILL DEVELOP OVER THE HILL
COUNTRY AND A SUBTLE HIGH OVER THE PINEY WOODS SHOULD HELP TO BACK
SURFACE WINDS AHEAD OF THE FRONT. A FEW SHOWERS WILL DEVELOP AHEAD OF
THE FRONT. WITH THE RECENT ACTIVITY SHOWING NO SIGNS OF PRODUCING
LIGHTNING...HAVE KEPT WITH VCSH. A LOW LEVEL INSTABILITY AXIS TRIES
TO BUILD...BUT IT APPEARS THAT THE MORE CONDUCIVE ENVIRONMENT FOR
THUNDER WILL BE WEST OF THE WACO TAF SITE. 5-10 KNOT WINDS WILL
CONTINUE TO BACK TOWARDS THE NORTH WITH THE PASSAGE OF THE FRONT
AROUND 02-03 UTC. WINDS SHOULD REMAIN LIGHT OVERNIGHT BEFORE
INCREASING AFTER SUNRISE ON FRIDAY WHEN DEEP MIXING WILL OCCUR.

15-BAIN/30

&&

.UPDATE...
NO UPDATES WERE NECESSARY TO THE SHORT TERM FORECAST. STILL
LOOKING AT THE POSSIBILITY OF SOME ISOLATED THUNDERSTORM
DEVELOPMENT LATE AFTERNOON AND EARLY EVENING WITH THE MOST FAVORED
AREA FROM MCKINNEY SOUTHWESTWARD TO MINERAL WELLS AND INCLUDING
MUCH OF THE METROPLEX. LEFT POPS IN THE 20 TO 30 PERCENT RANGE.
THIS EVENING THE FOCUS FOR ISOLATED SHOWER AND THUNDERSTORM
DEVELOPMENT WILL SHIFT TO THE WEST AND SOUTHWEST AND THE MOST
FAVORED AREA WILL BE OVER THE WACO AND KILLEEN AREAS AND AREAS
WEST TO OUR SOUTHWEST ZONES TOWARDS COMANCHE. HAVE LEFT POPS OVER
THESE AREAS AT 40 PERCENT. MUCH OF THIS AREA IS BEING HIGHLIGHTED
BY THE STORM PREDICTION CENTER AS HAVING A MARGINAL SEVERE
THUNDERSTORM RISK AND WE ARE IN GENERAL AGREEMENT WITH THE
THINKING THAT A STORM OR TWO COULD BE STRONG TO SEVERE WITH GUSTY
WINDS AND SMALL HAIL. TORNADOES ARE NOT EXPECTED.

HOETH

&&

.PREV DISCUSSION... /ISSUED 419 AM CDT THU OCT 30 2014/
OUR FIRST WEATHER CONCERN WILL BE WITH THE NORTHERN PLAINS COLD
FRONT SURGING SOUTH INTO THE SOUTHERN PLAINS THIS AFTERNOON...AS
A NORTHWEST FLOW SHORTWAVE MOVES QUICKLY SOUTHEAST. A SURFACE LOW
OVER EASTERN SOUTH DAKOTA WILL MOVE INTO CENTRAL MISSOURI BY
MIDDAY. THE COLD FRONT CROSS THE RED RIVER BY LATE AFTERNOON...THEN
THROUGH THE REMAINDER OF NORTH AND CENTRAL TEXAS TONIGHT. MODELS
CONTINUE TO SHOW MOISTURE INCREASING AHEAD OF THE FRONT...PARTICULARLY
ACROSS THE SOUTHWEST HALF OF OUR COUNTY WARNING AREA THROUGH THE
DAY WITH PWAT VALUES APPROACHING 1.15-1.3 INCHES. HIGH RESOLUTION
MODELS ARE SIGNALING HIGHER RAIN CHANCES THAN IN PREVIOUS RUNS
FROM THE DFW METRO SOUTHWEST INTO THE NORTHERN HILL COUNTRY. THE
GFS AND HRRR ARE THE DRIEST SOLUTIONS AND KEEP CONVECTIVE ACTIVITY
ISOLATED...WHILE THE ECMWF/VARIOUS WRF MODELS INDICATE SCATTERED
COVERAGE...WHILE THE SREF/NAM12 MODELS THE WETTEST. ALL THESE
VARIABLE SOLUTIONS CREATED QUITE A QUANDARY FOR FORECASTING RAIN
CHANCES LATER TODAY AND HOW MUCH TO RAMP THEM UP.

AFTER COLLABORATING WITH SEVERAL NEIGHBORING OFFICES...THE DECISION
AGREED UPON WAS TO RAISE POPS...BUT STAY CONSERVATIVE AND LEAN
TOWARD THE MIDDLE OF THE ROAD ECMWF/WRF PROJECTIONS. MOISTURE DOES
INCREASE...BUT IS NOT OVERLY RICH WITH BEST VALUES ACROSS OUR
SOUTHWEST COUNTIES. THE GENERAL FEELING WAS THAT THERE WOULD BE
ENOUGH FORCING TRAILING FROM THE SHORTWAVE MOVING THROUGH THE
OZARKS AND INTO THE LOWER MISSISSIPPI VALLEY TONIGHT IN ADDITION
TO THE SURFACE FORCING ALONG THE COLD FRONT TO RAISE AREAS SOUTH
OF I-20 AND WEST OF I-35 INTO THE CHANCE CATEGORY. INSTABILITY BOTH
SURFACE AND ALOFT APPEARS MARGINAL...BUT STRONG NORTHWEST BULK
SHEAR ON THE ORDER OF 40 KTS MAY LEND TO A STRONG STORM OR TWO
FROM LATE AFTERNOON INTO THIS EVENING. HOWEVER...THE MAJORITY OF
CONVECTIVE ACTIVITY SHOULD REMAIN OF THE GENERAL VARIETY.

COOL AND BRISK CONDITIONS ARE EXPECTED BEHIND THE COLD FRONT BY
FRIDAY MORNING. THE ORIGIN OF THIS NEXT AIRMASS IS OUT OF NORTH-
CENTRAL CANADA WHERE TEMPERATURES ARE PRETTY CHILLY. HIGHS ARE
ONLY EXPECTED TO BE IN THE 60S NORTH TO THE LOWER 70S ACROSS
CENTRAL TEXAS FRIDAY WITH BRISK NORTH WINDS. THE GUSTY WINDS WILL
SETTLE DOWN DURING THE EVENING HOURS FRIDAY FOR TRICK OR TREATERS
OR THOSE HEADING TO AREA HIGH SCHOOL FOOTBALL GAMES. NEVERTHELESS...
TEMPERATURES BY NIGHTFALL WILL BE IN THE 50S AND WILL FALL READILY
INTO THE MID- UPPER 40S BY LATE EVENING ACROSS MOST AREAS...SO
BRINGING A LIGHT COAT OR JACKET IS HIGHLY RECOMMENDED FOR ANY
OUTDOOR ACTIVITIES FRIDAY EVENING. THE WINDS WILL BECOME LIGHT
NORTHEAST BY SATURDAY MORNING WITH POSSIBLE FROST ON THE PUMPKINS
ACROSS RURAL AREAS NORTH OF I-20...AS LOW TEMPERATURES FALL WELL
INTO THE 30S. ANY EXTENT OF FROST WILL REALLY DEPEND ON ANY NEAR-
SURFACE MOISTURE THAT MAY BE PRESENT. MIGHT NOT BE A BAD IDEA TO
PROTECT SENSITIVE OUTDOOR PLANTS AND VEGETATION FRIDAY NIGHT/SATURDAY
MORNING AND MAKE SURE OUTDOOR PETS ARE PREPARED FOR THIS ROUND OF
COLDER AIR. A SURFACE HIGH SETTLES ACROSS THE OZARKS DURING THE
DAY SATURDAY WITH HIGHS WARMING ONLY INTO THE 60S...DESPITE
SOUTHEAST WINDS RETURNING AND ABUNDANT SUNSHINE. LEE SURFACE
CYCLOGENESIS OVER THE HIGH PLAINS ALONG WITH AN UPPER RIDGE SETTLING
OVER THE AREA SATURDAY NIGHT INTO SUNDAY WILL RESULT IN BREEZY
SOUTH WINDS AND TEMPERATURES SLOWLY MODERATING BACK UP TO NEAR 70
DEGREES FOR HIGHS SUNDAY.

THE LONGWAVE UPPER TROUGH CURRENTLY ENTERING THE U.S. WEST COAST
WILL BE OUR NEXT SYSTEM OF INTEREST FOR THE EARLY HALF OF NEXT
WEEK. THIS SYSTEM WILL TRACK EAST OVER THE ROCKIES OVER THE
WEEKEND AND BEGIN AFFECTING THE WESTERN HIGH PLAINS BY MONDAY.
WE EXPECT MONDAY TO BE MOSTLY DRY AS THE INCREASING SOUTHWEST
FLOW ALOFT WILL LIKELY ENHANCE THE CAPPING INVERSION OVER MUCH OF
THE AREA WITH PLENTY OF STRATUS UNDERNEATH THE INVERSION. MODELS
NOW HAVE THIS SYSTEM MORE OF AN OPEN AND DEEP WAVE THIS RUN VERSUS
BEING CUT OFF ON RUNS 24 HOURS AGO. THOUGH MOVEMENT WILL BE SLOW...
WE DO EXPECT THE SYSTEM TO EJECT OVER THE AREA TUESDAY INTO TUESDAY
NIGHT...AS MID LEVEL TROPICAL MOISTURE GETS PICKED UP FROM AN OLD
PACIFIC TROPICAL SYSTEM. WE PLAN TO CARRY HIGH RAIN CHANCES
TUESDAY AND TUESDAY NIGHT...AS THE SURFACE COLD FRONT MOVES INTO
THE AREA.

BY WEDNESDAY AND BEYOND...THE ECMWF AND GFS BEGIN TO WIDELY DIVERGE
ON HOW THE SOUTHERN PIECE OF ENERGY ALOFT IS HANDLED. THE GFS
REMAINS PROGRESSIVE THE SYSTEM AND COLD FRONT...WHILE THE ECMWF
CUTS IT OFF AND DROPS IT EVEN FURTHER SOUTH OVER NORTHERN MEXICO
BY WEDNESDAY WITH THE FRONT STALLING ACROSS THE AREA. THE ECMWF
SOLUTION WOULD KEEP THE AREA WET INTO THE LATE WEEK PERIOD...BUT THE
GFS DRIES THINGS OUT. FOR NOW...WILL GO WITH LOWER POPS THAN
GUIDANCE AND AWAIT LATER MODEL RUNS TO BETTER RESOLVE THINGS.

05/



&&

.SYNOPSIS...
QUIET WEATHER WAS OCCURRING ACROSS THE REGION THIS MORNING...AS
A SURFACE RIDGE OF HIGH PRESSURE EXTENDED FROM THE GREAT LAKES
SOUTHWEST INTO TEXAS. A COLD FRONT WAS PROGRESSING SOUTH ACROSS
THE HIGH PLAINS OF THE DAKOTAS AND EASTERN MONTANA WITH A SURFACE
TROUGH EXTENDING FROM EASTERN SOUTH DAKOTA SOUTH INTO SOUTHEAST
COLORADO AND NORTHEAST NEW MEXICO. A SHORTWAVE WAS SEEN ON WATER
VAPOR SATELLITE IMAGERY MOVING SOUTHEAST ACROSS THE UPPER MIDWEST
AND NORTHERN PLAINS THIS MORNING...WHILE ANOTHER STRONG UPPER
SYSTEM WAS APPROACHING THE U.S. WEST COAST.

&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  80  53  66  40  62 /  30  20   0   0   0
WACO, TX              79  53  70  40  64 /   5  30   0   0   0
PARIS, TX             73  46  63  34  59 /  10  10   0   0   0
DENTON, TX            78  48  65  36  61 /  30  10   0   0   0
MCKINNEY, TX          76  50  65  34  61 /  30  10   0   0   0
DALLAS, TX            79  55  67  40  62 /  20  20   0   0   0
TERRELL, TX           77  52  67  38  62 /  10  20   0   0   0
CORSICANA, TX         77  54  69  40  62 /   5  20   0   0   0
TEMPLE, TX            78  54  71  41  64 /   5  40   0   0   0
MINERAL WELLS, TX     80  48  67  36  63 /  30  20   0   0   0

&&

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

&&

$$

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