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

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000
FXUS64 KFWD 282042
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
342 PM CDT MON JUL 28 2014

.DISCUSSION...
A WEAK COLD FRONT ENTERED CENTRAL TEXAS THIS AFTERNOON BUT HAS
BECOME NEARLY STATIONARY...DESPITE INCREASING SURFACE WINDS BEHIND
THE BOUNDARY. THUNDERSTORMS HAVE DEVELOPED ALONG AND BEHIND THE
SURFACE BOUNDARY AS MEAGER MECHANICAL FORCING ABOVE THE FRONTAL
SLOPE IS HELPING VERY UNSTABLE AIR OVERCOME DEEP SUBSIDENCE. JULY
SUNSHINE AND STRONG SURFACE HEATING NORTH OF THE BOUNDARY HAS
ALLOWED POSTFRONTAL AIR TO MIX WITH THE AIR ABOVE THE FRONTAL
INVERSION...RESULTING IN THE UNUSUAL SITUATION OF SURFACE-BASED
CONVECTION BEHIND A FRONTAL BOUNDARY.

WITH CAPE VALUES EXCEEDING 2000J/KG WHERE CONVECTION IS ONGOING...
AND PW VALUES TOPPING 2 INCHES...STRONG UPDRAFTS WILL ALLOW FOR
SIGNIFICANT PRECIP LOADING. THE WEAK SHEAR IS RESULTING IN SLOW-
MOVING STORMS CAPABLE OF VERY HEAVY RAIN...BUT INDIVIDUAL UPDRAFTS
WILL GENERALLY BE TOO SHORT-LIVED FOR ANY FLOODING CONCERNS. RAIN-
COOLED AIR AND ASSOCIATED CLOUD COVER HAVE BEGUN TO NARROW DEW
POINT DEPRESSIONS AT THE SURFACE...BUT SOME CELLS WILL STILL BE
CAPABLE OF PRODUCING DOWNBURST WINDS IN EXCESS OF 50 MPH...
PARTICULARLY WITH COLLAPSING STORMS.

ALTHOUGH COOL/DRY ADVECTION BEHIND THE BOUNDARY HAS SO FAR BEEN
MODEST...THE 60-DEGREE ISODROSOTHERM IS EXPECTED TO SLIP SOUTH OF
THE RED RIVER TONIGHT. THE NORTHERN EXTENT OF THE ONGOING
CONVECTION...WHICH IS NOW FROM SHERMAN/DENISON TO NEAR LAKE
TAWAKONI...WILL DRIFT SOUTHWESTWARD AS DRIER AIR INVADES FROM THE
NORTHEAST. THE AXIS OF ELEVATED INSTABILITY...AND THE PRIMARY
FOCUS FOR ACTIVITY TONIGHT...WILL SET UP ACROSS THE SOUTHWESTERN
ZONES. THIS CONVECTION MAY PERSIST INTO THE LATE MORNING ON
TUESDAY. AN UNUSUAL GRADIENT BETWEEN DRY CONDITIONS IN EAST TEXAS
AND MARITIME TROPICAL AIR IN WESTERN NORTH TEXAS WILL KEEP THE
TUESDAY AFTERNOON ACTIVITY PRIMARILY WEST OF I-35.

THE FIRST OF A PAIR OF SHORTWAVES EMBEDDED IN NORTHWEST FLOW ALOFT
WILL SWING INTO OKLAHOMA ON WEDNESDAY...WITH ITS TRAILING FRIEND
EVENTUALLY GLIDING THROUGH NORTH TEXAS ON THURSDAY WITH AN
ASSOCIATED COLD FRONT. THE BEST CHANCES FOR PRECIPITATION
THROUGHOUT THE PERIOD WILL BE IN AREAS NORTH OF THE I-20 CORRIDOR
AND IN NORTHEAST TEXAS...BUT AREAS FARTHER SOUTH COULD SEE SOME
ACTIVITY THURSDAY AFTERNOON AS THE FRONT MOVES THROUGH THE REGION.
PORTIONS OF CENTRAL TEXAS COULD REACH THE CENTURY MARK WEDNESDAY
IF THE CLOUD COVER AND PRECIPITATION FAIL TO MAKE AN IMPACT
THERE...PARTICULARLY IN AREAS THAT MISS THE RAINFALL MONDAY AND
TUESDAY. THURSDAY TEMPERATURES ARE LARGELY DEPENDENT ON THE
EXTENT OF RAINFALL AND LINGERING CLOUD COVER...BUT EVEN CENTRAL
TEXAS WILL SEE MILDER AIR ARRIVE ON THURSDAY AND FRIDAY.

MID-SUMMER COLD FRONTS ARE ALWAYS DIFFICULT FOR GUIDANCE TO
HANDLE...BUT THE UPPER PATTERN SUGGESTS THAT THE BOUNDARY SHOULD
BE ABLE TO CLEAR THE CWA...BRINGING AN END TO RAIN CHANCES
THURSDAY NIGHT. HOWEVER...CHOSE TO LEAVE SOME LINGERING POPS IN
THE SOUTHEAST ON FRIDAY IN CASE THE FRONT IS NOT SO INCLINED.

NORTHWEST FLOW WILL CONTINUE INTO THE UPCOMING WEEKEND...AND NORTH
WINDS SHOULD PREVAIL AT THE SURFACE. ABUNDANT SUNSHINE WILL STILL
ALLOW TEMPERATURES TO REACH THE 90S...BUT THE HUMIDITY MAY BE A
BIT MORE TOLERABLE THAN IT USUALLY IS IN EARLY AUGUST.

25

&&

.AVIATION...
/ISSUED 1246 PM CDT MON JUL 28 2014/
CONCERNS...POSSIBLE ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS
THIS AFTERNOON.

MOSTLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH 00Z
WEDNESDAY. A COLD FRONT THAT EXTENDED SOUTH OF A BROWNWOOD /KBWD/
TO WACO /KACT/ TO PALESTINE /KPSN/ LINE WILL SINK FARTHER SOUTH
THIS AFTERNOON BEFORE BECOMING STATIONARY ACROSS CENTRAL TEXAS
THIS EVENING. WINDS TO THE NORTH OF THE FRONT THROUGH THIS
EVENING WILL BE NORTH TO NORTHEAST AROUND 10 KNOTS AND TO THE
SOUTH WINDS WILL BE SOUTH TO SOUTHEAST AROUND 10 KNOTS. A COMPLEX
OF SHOWERS AND THUNDERSTORMS BETWEEN CHILDRESS /KCDS/...GAINESVILLE
/KGLE/ AND WOODWARD OKLAHOMA /KWWR/ SHOULD WEAKEN THOUGH 20Z.
ISOLATED SHOWERS BETWEEN GAINESVILLE /KGLE/ AND GILMER /KJXI/
SHOULD ALSO WEAKEN LATER THIS AFTERNOON AS THE BEST CHANCES OF
CONVECTION SHIFT SOUTHWARD.

FOR THE METROPLEX TAF SITES...HAVE PLACED VCSH FOR THE 18-22Z
PERIOD TO ACCOUNT FOR ANY ISOLATED SHOWERS THAT MAY DEVELOP.
AFTERWARD...A SLIGHT CHANCE WILL REMAIN THIS EVENING THROUGH
TUESDAY BUT THE CHANCES ARE NOT HIGH ENOUGH TO INCLUDE IN THE TAFS
AT THIS TIME. NORTH TO NORTHEAST WINDS AROUND 10 KNOTS WILL BECOME
EASTERLY BY MIDDAY TUESDAY...AND SHOULD BECOME SOUTHEAST TUESDAY
AFTERNOON.

FOR WACO...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP LATE AFTERNOON...FOR NOW HAVE PLACED VCTS IN
THE WACO TAF FOR THE 20Z-00Z PERIOD. A SLIGHT CHANCE WILL
CONTINUE TONIGHT AND FRIDAY...BUT ONCE AGAIN THE CHANCES ARE NOT
HIGH ENOUGH TO MENTION IN THE TAF.

58


&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  74  95  74  95  74 /  30  20  10  20  40
WACO, TX              74  96  73  98  74 /  40  30  10  10  20
PARIS, TX             69  90  69  81  67 /  20  10  30  50  60
DENTON, TX            71  94  73  94  71 /  30  20  20  30  40
MCKINNEY, TX          70  92  71  93  72 /  30  20  20  40  50
DALLAS, TX            75  94  75  95  74 /  30  20  10  20  40
TERRELL, TX           71  94  71  94  73 /  30  20  10  30  40
CORSICANA, TX         73  94  72  96  72 /  40  20  10  10  30
TEMPLE, TX            73  96  72  98  74 /  40  30  20  10  20
MINERAL WELLS, TX     70  94  71  97  73 /  30  30  20  20  30

&&

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

&&

$$

14/25





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