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

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS64 KFWD 231747 AAA
AFDFWD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1247 PM CDT SAT MAY 23 2015

.AVIATION...

CONCERNS...CONVECTION...HEAVY RAIN...MVFR TO LIFR CONDITIONS.

DESIGNING THE 18Z TAFS IS DIFFICULT DUE TO THE EXTENT OF
CONVECTIVE DEVELOPMENT AND MOVEMENT OVER THE NEXT 24 HOURS. BEST
GUESS IS A SLOW TRANSITION TO MVFR CIGS EARLY AFTERNOON AND A
RETURN TO IFR CIGS THIS EVENING AS THE MAIN CONVECTIVE SYSTEM
MOVES INTO THE REGION. SOME PERIODS OF LIFR CIGS POSSIBLE DURING
HEAVY RAINFALL. WITH VERY MOIST AIR IN PLACE...VFR VIS WILL BE
PRESENT BUT CONVECTIVE ELEMENTS SHOULD PRODUCE MVFR VIS FOR A
WHILE AND DECIDED TO KEEP 5SM BR AS PREVAILING. CONDITIONS WILL
BEGIN TO IMPROVE BY LATE SUNDAY MORNING AS THE CONVECTIVE SYSTEM
MOVES FARTHER EAST...BUT THE TRANSITION WILL BE SLOW.

SCATTERED CONVECTION IS EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THIS AFTERNOON AND PERSIST INTO THE EVENING HOURS. SOME
MARGINALLY SEVERE CELLS ARE POSSIBLE AT ANY ONE TAF SITE.
LATER THIS EVENING...A LARGE CONVECTIVE COMPLEX TO THE
WEST-NORTHWEST WILL SPREAD OVER THE REGION TONIGHT AND LAST THROUGH
AT LEAST MIDDAY SUNDAY...PROVIDING FOR LONG DURATION OF
PRECIPITATION /1 TO 3+ INCHES/... PERIODS OF MODERATE TO HEAVY
RAINFALL AND CONSIDERABLE LIGHTNING...WHICH WILL ALL AFFECT DFW
GROUND OPERATIONS...AND OVERNIGHT ARRIVALS AND DEPARTURES.  75


&&

.UPDATE...
IN THE WAKE OF THE PASSING WARM FRONT EARLY THIS MORNING THE
ATMOSPHERE IS BECOMING MORE UNSTABLE AND CONTINUES TO MOISTEN UP.
AS THE UPPER TROUGH CONTINUES TO MOVE EASTWARD...UPPER LEVEL
FORCING WILL INCREASE ACROSS THE STATE FROM WEST TO EAST. SOME
SCATTERED SHOWERS AND STORMS WILL STREAM NORTHWARD ACROSS THE
AREA THIS AFTERNOON. HOWEVER...THE PRIMARY ACTIVITY WE WILL BE
WATCHING SHOULD DEVELOP MID-LATE AFTERNOON JUST WEST OF THE CWA
AND TRACK INTO THE NORTHWESTERN ZONES. MODEL SOUNDINGS SHOW ENOUGH
LOW LEVEL INSTABILITY AND WIND SHEAR TO BE CONCERNED ABOUT AN
ISOLATED TORNADO THREAT...ESPECIALLY ACROSS THE NORTHWEST CWA...SO
WE WILL WATCH THIS CLOSELY. OVERALL THE INSTABILITY VALUES ARE
NOT TOO IMPRESSIVE...SO THE HAIL THREAT MAY END UP BEING MORE
MARGINAL.

OTHERWISE STILL EXPECT A NORTH-SOUTH BAND OF RAIN AND STORMS TO
ORGANIZE THIS EVENING AND MAKE A SLOW EASTWARD TREK ACROSS THE
REGION TONIGHT AND SUNDAY. THE HEAVIEST RAIN SHOULD FALL ACROSS
THE NORTHWEST ZONES TONIGHT...AND THE SYSTEM SHOULD START TO GAIN
MORE EASTWARD MOTION LATE TONIGHT AND INTO SUNDAY. OF
NOTE...BECAUSE IT APPEARS A LARGE CONVECTIVE SYSTEM WILL ALSO
DEVELOP AND TRACK ACROSS SOUTH CENTRAL AND SOUTH TEXAS
TONIGHT...THIS MAY HAVE THE EFFECT OF USING UP SOME OF THE HIGH
MOISTURE AND INSTABILITY FOR AREAS JUST NORTH OF THIS SYSTEM.
ESSENTIALLY THERE IS A POSSIBILITY THAT THE SOUTHERN HALF OF THE
CWA WILL BE IN A RELATIVE RAINFALL MINIMUM AND ONLY RECEIVE 1-2
INCHES OF RAINFALL. THESE TYPES OF FORECASTS ARE
DIFFICULT...BECAUSE THE MESOSCALE FEATURES CAN AND USUALLY HAVE A
GREATER AFFECT ON WHAT HAPPENS. THE SCALE OF THESE FEATURES ARE
JUST BEYOND THE CAPABILITY OF MOST MODEL COMPUTER GUIDANCE TO
CAPTURE...SO WE WILL WATCH THE CURRENT TRENDS CLOSELY AND MAKE
ADJUSTMENTS TO THE FORECAST AS THEY BECOME MORE APPARENT.

FOR THE UPDATE HAVE RE-WORKED POPS OVER THE NEXT FEW DAYS BASED ON
A QUICK LOOK AT THE 12Z GUIDANCE. OBVIOUSLY BEST CHANCES OF RAIN
ARE TONIGHT AND SUNDAY...BUT IT IS BECOMING MORE LIKELY A ROUND OF
SEVERE WEATHER AND HEAVY RAINFALL WILL AFFECT THE SOUTHEAST HALF
OF THE CWA MONDAY AFTERNOON AND EVENING.

TR.92

&&

.PREV DISCUSSION... /ISSUED 337 AM CDT SAT MAY 23 2015/
DEWPOINTS ARE CREEPING UP ACROSS NORTH TEXAS EARLY THIS MORNING AS
A WARM FRONT MOVE SLOWLY NORTH ACROSS THE AREA. THE BOUNDARY
STRETCHES ROUGHLY ALONG OR JUST NORTH OF THE I-20 CORRIDOR AND IS
EXPECTED TO REACH THE RED RIVER BY MIDDAY. THIS IS ALL IN RESPONSE
TO A STRENGTHENING LEE ROCKIES SURFACE CYCLONE...WHICH ITSELF HAS
DEVELOPED IN RESPONSE TO A DEEP UPPER LOW OVER THE 4-CORNERS
REGION. WATER VAPOR IMAGERY INDICATES A POTENT SHORTWAVE NOW
ROTATING AROUND THE UPPER LOW ACROSS THE DESERT SOUTHWEST.

STRONG FORCING FROM THIS SHORTWAVE HAS ALREADY BEGUN TO GENERATE
CONVECTION ACROSS EASTERN NEW MEXICO AND PARTS OF SOUTHWEST TEXAS.
SHOWERS AND THUNDERSTORMS WILL LIKELY SPREAD EAST ACROSS WEST-
CENTRAL TEXAS THIS MORNING AND BEGIN TO AFFECT WESTERN COUNTIES OF
NORTH TEXAS BY MIDDAY. BY THAT TIME...PWATS WILL HAVE JUMPED TO
JUST SHY OF TWO INCHES. INSTABILITY WILL BE MARGINAL TODAY...BUT
GOOD LIFT ASSOCIATED WITH THE INITIAL SHORTWAVE COMBINED WITH
IMPRESSIVE MOISTURE PROFILES SHOULD LEAD TO SCATTERED CONVECTION
/CONTAINING MANY EFFICIENT RAIN-PRODUCING CELLS/ THIS AFTERNOON.
THE FLASH FLOOD WATCH WILL BEGIN AREA-WIDE TODAY...THOUGH THE BEST
POTENTIAL FOR CONVECTION WILL LIKELY BEGIN IN THE NORTHWEST WHERE
THE STRONGEST FORCING RESIDES. CAPE OF 1000-1500 J/KG DURING PEAK
HEATING WILL RESULT IN A FEW SEVERE STORMS WITH LARGE HAIL AND
DAMAGING WINDS.

THE UPPER LOW WILL REMAIN NEARLY STATIONARY THIS EVENING AS A
SECOND SHORTWAVE MOVES EAST ACROSS MEXICO INTO WEST TEXAS. THIS
SHOULD GENERATE ANOTHER ROUND OF CONVECTION DURING THE EVENING AND
OVERNIGHT HOURS ON TOP OF AREAS WHICH ARE ALREADY SATURATED...AND
WILL LIKELY HAVE RECEIVED CONVECTION BY THIS AFTERNOON. SOME
HIGH-RES GUIDANCE SUGGESTS THUNDERSTORMS ORGANIZING INTO A LINE
AND PROGRESSING SLOWLY EAST ACROSS THE REGION OVERNIGHT TONIGHT.
THE SLOW EASTWARD PROGRESSION IMPLIES THAT THUNDERSTORM CELLS WILL
HAVE THE OPPORTUNITY TO TRAIN OVER SATURATED AREAS FOR PROLONGED
PERIODS OF TIME...FURTHER SUPPORTING HEAVY RAIN POTENTIAL AND
CONTINUED OPPORTUNITIES FOR FLASH FLOODING. PRECIPITATION WILL
EVENTUALLY SHIFT EAST OF THE REGION DURING THE DAY SUNDAY AS THE
UPPER LOW SHIFTS NORTHEAST INTO THE NORTHERN PLAINS AND THE
SHORTWAVE HEADS FOR THE OHIO VALLEY.

WHATEVER BREAK WE RECEIVE WILL BE SHORT LIVED...BECAUSE ANOTHER
ROUND OF CONVECTION WILL TRANSPIRE ON MONDAY AS ANOTHER SHORTWAVE
/WHICH APPEARS TO CURRENTLY RESIDE IN THE PAC NORTHWEST/ SWINGS
EAST ACROSS THE SOUTHERN PLAINS. HIGHER LEVELS OF SHEAR AND
INSTABILITY WILL LEAD TO A BETTER CHANCE OF SEVERE THUNDERSTORMS
WITH THIS SYSTEM. THE SYSTEM WILL MOVE RELATIVELY FAST...BUT
LOCALIZED HEAVY RAIN WILL STILL CREATE ADDITIONAL FLOODING
CONCERNS FOR MEMORIAL DAY. STORMS WILL LIKELY ORGANIZE UPSCALE
INTO A SQUALL LINE AND PUSH EAST OF THE REGION MONDAY NIGHT OR
EARLY TUESDAY.

SHORTWAVE RIDGING SHOULD BRING QUIETER WEATHER TO THE AREA TUESDAY
AND WEDNESDAY...THOUGH WE WILL CONTINUE TO KEEP LOW POPS IN PLACE
FOR WIDELY SCATTERED DIURNAL CONVECTION. THIS TYPE OF ACTIVITY IS
USUALLY DISORGANIZED AND DRIVEN BY DAYTIME HEATING...BUT TENDS TO
BE FAIRLY EASY TO COME BY DURING A WET WEATHER PATTERN. SHOWERS
AND THUNDERSTORMS WILL BECOME MORE NUMEROUS THURSDAY AND FRIDAY AS
YET ANOTHER UPPER TROUGH APPROACHES THE PLAINS.    30



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  79  68  77  69  83 /  50  90  80  30  50
WACO, TX              81  70  79  69  82 /  50  80  80  30  60
PARIS, TX             80  69  75  67  79 /  40  60  90  50  40
DENTON, TX            78  68  76  66  82 /  60  90  80  30  40
MCKINNEY, TX          80  68  76  67  81 /  50  80  90  40  40
DALLAS, TX            80  69  78  69  83 /  50  90  80  30  50
TERRELL, TX           81  70  77  68  82 /  40  70  80  40  50
CORSICANA, TX         81  70  77  69  82 /  40  70  80  40  70
TEMPLE, TX            81  68  80  69  81 /  40  80  70  30  60
MINERAL WELLS, TX     77  67  79  67  82 /  60 100  70  20  40

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.


&&

$$

75


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.