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

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000
FXUS64 KFWD 230837
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
337 AM CDT SAT MAY 23 2015

.DISCUSSION...
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

&&

.AVIATION...


FOR THE 06Z TAFS...NO SIGNIFICANT CHANGES MADE FROM THE 00Z
TAFS.

WATCHING THE POSITION OF THE WARM FRONT WILL BE CRITICAL DURING
THE EARLY MORNING HOURS. IFR CEILINGS ARE LIKELY TO REMAIN CLOSELY
TIED TO THE WARM FRONT...SO IF IT LIFTS NORTH FASTER OR REMAINS IN
PLACE LONGER THAN EXPECTED...THE DURATION OF IFR CIGS WILL BE
AFFECTED APPROPRIATELY. REMOVED IFR CIGS FROM KACT AS THE WARM
FRONT IS NORTH OF THE AIRPORT AT THIS TIME...ANY IFR CIGS ARE
EXPECTED TO BE TEMPORARY AS A RESULT.

WIDESPREAD PRECIPITATION IS STILL EXPECTED TO BUILD OVER THE
REGION FROM WEST TO EAST BEGINNING TOMORROW LATE AFTERNOON.

CAVANAUGH

.../PREVIOUS AVIATION DISCUSSION/...
/ISSUED 727 PM CDT FRI MAY 22 2015/

FOR THE 00Z TAFS...TIMING THE ONSET OF LOW MVFR AND IFR STRATUS
RETURNING TO THE REGION AND THEN RAIN SHOWER AND THUNDERSTORM
CHANCES OVER THE NEXT 24-36 HOURS ARE THE PRIMARY FORECAST
CHALLENGES.

23Z SURFACE ANALYSIS INDICATED LOW-LEVEL MOISTURE RETURNING
RAPIDLY TO THE REGION FROM THE TEXAS GULF COAST NORTHWEST OVER
WEST CENTRAL TEXAS. THIS DEEP MOISTURE RETURN WILL RESULT IN CLOUD
HEIGHTS LOWERING FROM THE 2 TO 3 THOUSAND FOOT RANGE TO
APPROXIMATELY 800 FEET AGL TONIGHT. THESE CLOUDS ARE EXPECTED TO
MOVE OVER AREA AIRPORTS FROM THE WEST OR SOUTHWEST TO THE EAST.
HAVE LOW MVFR CIGS BUILDING IN AFTER 04Z...THEN IFR CIGS 4 HOURS
LATER. WILL MONITOR UPSTREAM TRENDS AND AMEND THE TAFS IF THIS
TIMING LOOKS LIKE IT WILL CHANGE. IFR CIGS ARE LIKELY TO HOLD
UNTIL THE LATE MORNING HOURS OF SATURDAY.

AFTER NOON ON SATURDAY...LARGE SCALE LIFT BEGINS TO INCREASE OVER
TEXAS FROM WEST TO EAST...RESULTING IN AN INCREASE IN RAIN CHANCES
FROM SATURDAY AFTERNOON THROUGH SATURDAY NIGHT. SCATTERED RAIN
SHOWERS ARE POSSIBLY ANYTIME ON SATURDAY...WITH THUNDERSTORMS
BECOMING MORE LIKELY LATE SATURDAY AFTERNOON. WIDESPREAD RAIN
SHOWER ACTIVITY WITH EMBEDDED THUNDERSTORMS IS LIKELY AT ALL AREA
AIRPORTS SATURDAY NIGHT. DID NOT PLACE THUNDER IN THE FORECAST AT
THIS TIME BECAUSE IT LOOKS LIKE WE WILL HAVE MANY HOURS OF
PRECIPITATION WITH EMBEDDED THUNDERSTORMS POSSIBLE.

DID NOT WANT TO ADVERTISE 10 TO 12 HOURS OF THUNDERSTORMS AT THIS
TIME...ALTHOUGH THIS IS A RARE SITUATION WHERE THIS IS ACTUALLY
POSSIBLE. ANY RAIN SHOWER OR THUNDERSTORM ACTIVITY SATURDAY NIGHT
IS EXPECTED TO RESULT IN HEAVY RAINFALL AND LIKELY IFR
VISIBILITIES. WENT AHEAD WITH A MENTION OF HEAVY RAIN IN AT THE
END OF THE DFW TAF. BEST WINDOW FOR WIDESPREAD HEAVY RAINFALL AT
AREA TAF SITES APPEARS TO BE JUST BEFORE MIDNIGHT TO 15Z SUNDAY AT
THIS TIME.

A WIDESPREAD HEAVY RAINFALL EVENT IS LIKELY ACROSS THE REGION THIS
WEEKEND...SO THE TAFS WILL LIKELY BE BUSY AND AMENDED FREQUENTLY
AS WE MOVE INTO SATURDAY AFTERNOON AND EVENING.

CAVANAUGH


&&

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

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 1 PM CDT THIS AFTERNOON THROUGH SUNDAY
EVENING FOR TXZ091>095-100>107-115>123-129>135-141>148-156>162-
174-175.


&&

$$



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