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

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FXUS64 KFWD 040623 AAD
AFDFWD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1223 AM CST WED MAR 4 2015

.UPDATE...
WITH DENSE FOG BEING REPORTED AT JACKSBORO AND ATHENS...HAVE
EXPANDED THE DENSE FOG ADVISORY TO INCLUDE THE ENTIRE FORECAST
AREA UNTIL 6 AM. ADJUSTMENTS TO THE EXPIRATION WILL LIKELY NEED
TO BE MADE FOR THE MAIN PACKAGE AS THE FOG MAY BE A PROBLEM PAST
6 AM TO THE SOUTH OF THE FRONT.

58

&&

.AVIATION...
/ISSUED 1142 PM CST TUE MAR 3 2015/
CIGS/VIS CONTINUE TO BOUNCE AROUND TONIGHT BUT GENERALLY IFR
CONDITIONS PREVAIL ACROSS NORTH TEXAS WITH VISIBILITIES AROUND 1SM
AND CIGS AROUND 500FT. THERE HAVE BEEN SOME TEMPORARY IMPROVEMENTS
BUT THESE SHOULD BECOME FEWER THROUGH THE NIGHT.

FORCING FROM AN APPROACHING UPPER LEVEL STORM SYSTEM WILL BEGIN
TO INCREASE OVERNIGHT RESULTING IN SOME LIGHT RAIN THAT DEVELOPS
DURING THE EARLY MORNING HOURS. THIS RAIN WILL BE AHEAD OF A COLD
FRONT THAT WILL MOVE THROUGH THE REGION. THE FRONT IS CURRENTLY
MOVING THROUGH OKLAHOMA AND WILL PUSH INTO THE AREA DURING THE
EARLY MORNING HOURS. IFR CONDITIONS ARE STILL EXPECTED TO PREVAIL
WITH RAIN COVERAGE INCREASING THROUGH THE DAY. THERE COULD BE AN
ISOLATED THUNDERSTORM BUT RAIN WILL PRIMARILY DOMINATE.

AS COLDER AIR FILTERS IN THROUGH LATE AFTERNOON...SOME LIGHT
FREEZING RAIN WILL START TO DEVELOP. THIS SHOULD OCCUR AT THE
MAJOR METROPLEX AIRPORTS BY 6PM OR SO ON WEDNESDAY EVENING.
INITIAL FREEZING RAIN SHOULD BE LIGHT AND WILL LIKELY RESULT IN
LITTLE TO NO INITIAL ICE ACCUMULATION. AS THE EVENING GOES
ON...MUCH COLDER AIR WILL MOVE IN AND WE WILL SEE A TRANSITION
OVER TO SLEET. IT APPEARS THAT AT LEAST ONE SIGNIFICANT BAND OF
MODERATE TO HEAVY SLEET WILL SET UP VERY NEAR THE METROPLEX DURING
THE LATE EVENING HOURS ON WEDNESDAY. THIS SHOULD PERSIST FOR A FEW
HOURS BEFORE THE BAND SLIDES TO THE EAST. SOME LIGHT SNOW WILL BE
POSSIBLE ON THE BACK SIDE OF THE BAND CLOSER TO MIDNIGHT
WEDNESDAY NIGHT. CONDITIONS WILL IMPROVE AFTER THE PRECIPITATION
ENDS INTO EARLY THURSDAY MORNING.

FARTHER SOUTH...AREAS OF RAIN WILL AFFECT WACO WITH IFR CONDITIONS
GENERALLY PREVAILING. SOME LIGHT FREEZING RAIN IS EXPECTED LATE
WEDNESDAY EVENING.

DUNN


&&


.PREV UPDATE...
.UPDATE...

CORRECTED THURSDAY TO WEDNESDAY

IN REFERENCE TO THE WINTER WEATHER EVENT...WE HAVE LOOKED AT THE
INCOMING 0Z MODEL GUIDANCE AS WELL AS THE 21Z SREF AND ALL
INDICATIONS ARE THAT THERE IS AN EXCELLENT SETUP FOR POST FRONTAL
PRECIPITATION. STRONG LIFT AHEAD OF THE UPPER LEVEL LOW THAT IS
CURRENTLY LOCATED NEAR BAJA WILL SPREAD OVER THE REGION AND WORK
IN CONJUNCTION WITH STRONG FRONTOGENESIS TO PRODUCE AN INTENSE SW
TO NE ORIENTED BAND ACROSS NORTH TEXAS WEDNESDAY NIGHT. THE
PRIMARY FORECAST CHALLENGE IS PRECIPITATION TYPES AND AMOUNTS
WHICH HINGE ON THE TEMPERATURES...NOT ONLY AT THE SURFACE BUT
THROUGH THE ATMOSPHERIC COLUMN. THE PREVIOUS FORECAST LOOKS GOOD
FOR TIMING OF THE CHANGEOVER AND WE SEE NO NEW DATA THAT SUGGESTS
WE NEED TO BUMP THE TIMING UP. ALTHOUGH THE COLD AIR DOES OFTEN
GET HERE FASTER THAN THE MODELS INDICATE...OUR TIMING IS AHEAD OF
THE USUALLY RELIABLE RAP/NAM FORECASTS.

INDICATIONS FROM THE 0Z GUIDANCE CONTINUE TO POINT TOWARD
CONVECTIVE INSTABILITY BEING AVAILABLE FOR ISOLATED THUNDERSTORMS
WITH HEAVY SLEET WEDNESDAY EVENING. THE STRONG LIFT WILL KEEP
COOLING THE MID-UPPER LEVELS DURING THE EVENING HOURS AND RESULT
IN A CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST...AND WE ARE
MORE CONCERNED ABOUT SOME HIGHER AMOUNTS OF SNOW ESPECIALLY NORTH
AND WEST OF THE DFW METROPLEX WHERE 1-2 INCHES MAY FALL. THE
PRIMARY AXIS OF PRECIPITATION LOOKS LIKE IT WILL OCCUR ROUGHLY
FROM COMANCHE TO DFW TO PARIS...BUT IT IS TOUGH TO SAY JUST HOW
MUCH OF THIS WILL BE SPENT AS RAIN AND HOW MUCH WOULD BE
ACCUMULATING SLEET OR SNOW. THE 21Z SREF RAISES CONCERNS THAT MORE
THAN 1 INCH OF SLEET WILL OCCUR WITHIN THIS BAND...AND THE 0Z NAM
AND HI-RES WRF MODELS ALSO SHOW THIS WILL BE THE FAVORED LOCATION
FOR OVER A HALF INCH OF SLEET. A TRANSITION TO SNOW WOULD OCCUR A
LITTLE LATER IN THE EVENING THAT MAY DROP AN ADDITIONAL INCH OF
SNOW WITHIN THIS PRECIPITATION AXIS BEFORE IT BEGINS TO END FROM
NORTHWEST TO SOUTHEAST AFTER MIDNIGHT.

ALSO WORTH NOTING ARE THE WIND SPEEDS TOMORROW EVENING. NORTHWEST
WINDS OF 20-25 MPH WITH HIGHER GUSTS WILL WORK TO REDUCE
VISIBILITIES BELOW A HALF MILE IN REGIONS WHERE A CHANGE OVER TO
MODERATE SNOW OCCURS.

FOR THE FORECAST...THE MAIN CHANGE WAS TO BUMP UP POPS WEDNESDAY
EVENING AREAWIDE. THERE WERE NO MAJOR CHANGES TO PRECIPITATION
TYPE OR THE TIMING OF THE CHANGE-OVER. HOWEVER GIVEN THE GOOD
SETUP...WE HAVE BUMPED UP SNOW/SLEET AMOUNTS ALONG AND NW OF A
LINE FROM COMANCHE TO DFW TO PARIS. WE ARE NOW EXPECTING 1/4 TO
1/2 INCH OF SLEET AND 1-2 INCHES OF SNOW NW OF A EASTLAND TO
DENTON TO BONHAM LINE. FOR THE LINE FROM COMANCHE TO THE METROPLEX
TO PARIS...WE ARE UP TO A HALF INCH OF SLEET AND AN INCH OF SNOW.
AMOUNTS TAPER OFF AS ONE HEADS FARTHER SOUTH...BUT DID BUMP THE
ZONE FROM WACO TO ATHENS UP TO A 1/4 TO 1/2 INCH OF SLEET.

WE ARE ON THE CUSP OF UPGRADING A PORTION OF THE WINTER WEATHER
ADVISORY TO A WINTER STORM WARNING AND IF THE 0Z GFS HAD NOT COME
IN WITH A FARTHER SOUTHWARD DISPLACEMENT OF THE MAIN QPF AXIS IN
COMPARISON TO THE OTHER MODELS...WE PROBABLY WOULD HAVE HAD THE
CONFIDENCE TO UPGRADE NOW. WE WILL DEFFER ANY DECISIONS TO THE
NEXT SHIFT WHO WILL HAVE THE BENEFIT OF THE ECMWF...ECMWF
ENSEMBLE...GFS ENSEMBLE...AND 3Z SREF. WARNING OR NOT...THIS
CERTAINLY LOOKS LIKE IT SHOULD BE A HIGH IMPACT WINTER WEATHER
EVENT FOR A GOOD PORTION OF THE CWA.

TR.92

&&



.SHORT TERM...

TEMPERATURES TODAY DID NOT WARM AS MUCH AS WE THOUGHT AND THE
DENSE FOG PERSISTED SOMEWHAT LONGER. STILL HAVE A FEW LOCATIONS
WITH VISIBILITY BELOW ONE MILE...BUT WEAK SHOWERS AND DRIZZLE
SHOULD HELP IMPROVE THEM A LITTLE BEFORE EVENING. BUT DO NOT
EXPECT TEMPERATURES TO COOL MUCH OVERNIGHT AND WILL KEEP AREAS OF
FOG MOST OF THE NIGHT.

THE COLD FRONT WAS JUST MOVING INTO THE TEXAS PANHANDLE AND
NORTHERN OKLAHOMA AT 2 PM. TEMPERATURES WERE IN THE TEENS AND 20S
BEHIND THE FRONT OVER KANSAS. WE EXPECT THE FRONT TO CROSS THE
RED RIVER JUST AFTER MIDNIGHT...INTO THE I-20/30 CORRIDOR AROUND
DAYBREAK AND THROUGH THE FAR SOUTHEAST COUNTIES 4-5 PM. IT WILL
TURN NOTICEABLY COLDER AND WINDY BEHIND THE FRONT. MAY NEED A WIND
ADVISORY FOR WEDNESDAY NIGHT IF MOS GUIDANCE NUMBERS ARE RIGHT.
THE FREEZING LINE WILL LAG MANY HOURS BEHIND THE FRONT...THUS A
PRECIPITATION TRANSITIONING TO A WINTRY MIX MAY NOT TAKE TAKE
PLACE IN THE NORTHWEST UNTIL MID AFTERNOON AND ACROSS THE DFW
METROPLEX UNTIL 5 PM. ALTHOUGH THIS IS OUR BEST GUESS ON THE
TRANSITION...AN HOUR OR TWO EARLIER WOULD RESULT IN MORE SERIOUS
TRAVEL IMPACTS FOR THE AFTERNOON COMMUTE. WE HAVE ISSUED A WINTER
WEATHER ADVISORY IN THREE SEGMENTS. ONE FOR THE EARLIER NORTHWEST
TIMING...ONE FOR THE CENTRAL AREAS INCLUDING THE METROPLEX TO
COVER THE LATE AFTERNOON COMMUTER IMPACT POTENTIAL AND ONE IN THE
SOUTHEAST WHERE THE TRANSITION OCCURS LATER WEDNESDAY NIGHT.
CURRENTLY...WE FEEL SLEET AMOUNTS UP TO 1/2 INCH AND FREEZING RAIN
AMOUNTS UP TO 1/10 INCH ARE THE MOST LOGICAL FOR THIS EVENT.

NEARLY ALL OF THE MODELS HAVE COME INTO BETTER AGREEMENT ON
TIMING...TRANSITION AND AMOUNTS OF PRECIPITATION. THE HI-RES
MODELS ARE ALSO INDICATING A POTENTIAL FOR CONVECTIVE ELEMENTS
MOVING OVER THE POST-FRONTAL COLD AIR WEDNESDAY EVENING. SLEET
SHOWERS WOULD RESULT IN ROADS BECOMING COVERED IN A SHORTER PERIOD
OF TIME. OTHER FACTORS AIDING THIS EVENT ARE: STRONG FRONTOGENETIC
FORCING...SIGNIFICANT LIFT ASSOCIATED WITH THE RIGHT-REAR ENTRANCE
REGION OF THE 250 MB JET ALOFT AND A PIECE OF SHORTWAVE ENERGY
MOVING OVER THE CWA.

WE WILL BE WATCHING NEW DATA AS IT ARRIVES TO RE-EVALUATE THE
POTENTIAL OF THIS SYSTEM AS A FEW MINOR DEVIATIONS HERE AND THERE
COULD CAUSE SIGNIFICANT CHANGES TO LATER FORECASTS.

THE PRECIPITATION WILL SHIFT TO THE SOUTHEAST COUNTIES ON
THURSDAY MORNING AND SHOULD END BEFORE MIDDAY. WIND CHILLS WILL BE
IN THE MID TEENS TO LOWER 20S DAYBREAK THURSDAY. HIGHS ON
THURSDAY WILL BE IN THE MID TO UPPER 30S WITH AROUND 40 FROM
CAMERON TO CENTERVILLE. EXPECT SUNSHINE TO RETURN TO THE ENTIRE
CWA BY THURSDAY AFTERNOON!

&&

.LONG TERM...
AN UPPER LEVEL SPLIT-PATTERN WILL BE DEVELOPING BY LATE WEEK WITH
A SHORT WAVE TROUGH ARRIVING FROM THE WEST ON SATURDAY.  TEMPERATURES
WILL SLOWLY MODERATE THROUGH THE PERIOD...AND THERE COULD BE SOME
LIGHT SHOWERS OVER THE SOUTHEAST COUNTIES ON SATURDAY. HIGHS WILL
START OUT IN THE MID 40S ON FRIDAY AND WARM INTO THE 60S FOR
MONDAY AND TUESDAY. LOWS WILL BE IN THE 20S ON FRIDAY MORNING...IN
THE UPPER 20S AND 30S ON SATURDAY THEN WARMING INTO THE 40S BY TUESDAY
MORNING. 75

&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  48  26  39  24  47 / 100  90  10   5   5
WACO, TX              61  30  39  24  47 /  90  90  20   5   5
PARIS, TX             50  25  39  23  45 / 100  90  10   5   5
DENTON, TX            48  24  39  23  46 / 100  90  10   5   5
MCKINNEY, TX          47  25  39  24  46 / 100  90  10   5   5
DALLAS, TX            48  26  40  25  47 / 100  90  10   5   5
TERRELL, TX           52  27  40  23  46 / 100  90  10   5   5
CORSICANA, TX         59  31  39  25  47 / 100  90  20   5   5
TEMPLE, TX            64  30  39  25  47 /  90  80  30   5   5
MINERAL WELLS, TX     50  24  38  22  47 / 100  90  10   5   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST
THURSDAY FOR TXZ093>095-103>107-116>123-129>134-141>145.

DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175.

WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST
THURSDAY FOR TXZ135-146>148-156>162-174-175.

WINTER WEATHER ADVISORY FROM NOON TODAY TO NOON CST THURSDAY FOR
TXZ091-092-100>102-115.


&&

$$

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