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

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FXUS64 KFWD 261726 AAC
AFDFWD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1226 PM CDT TUE AUG 26 2014

.AVIATION...
/18Z TAFS/

WE CONTINUE TO MONITOR A DISTURBANCE OVER THE NORTHWEST GULF OF
MEXICO. WATER VAPOR SATELLITE AND GOES SOUNDER DATA INDICATE THAT
THE RICHEST MOISTURE EXISTS FROM WACO INTO SOUTHEAST TEXAS.
CHALLENGES THE FIRST 12 HOURS WILL BE FROM ISOLATED SHOWERS AND
STORMS FROM MID AFTERNOON TO SUNSET.

A THICKENING CU FIELD AND ISOLATED CONVECTION HAS DEVELOPED
ACROSS CENTRAL TEXAS BETWEEN WACO AND MARLIN. MORE SUBSIDENT AIR
APPEARED EVIDENT WITH LESS CU DEVELOPMENT OVER DFW. A DEEPER EAST
FLOW COMPONENT WAS NOTED BY GOES DENSITY WINDS ACROSS CENTRAL AND
SOUTHEAST TEXAS CLOSER TO THE GULF DISTURBANCE. HAVE RETAINED VCTS
MENTION FOR WACO...BUT MAY NEED TO SPEED IT UP AN HOUR OR TWO.
THOUGH A ROGUE SHOWER OR STORM COULD DEVELOP ACROSS THE EASTERN
DFW METRO...CONFIDENCE IS NOT NEAR AS HIGH AS IT IS AT WACO AND
WILL NOT CARRY ANY MENTION OF VCTS. A BRIEF AMENDMENT CAN BE MADE
ON AN AIRPORT TO AIRPORT BASIS IF A STORM WAS TO DEVELOP UP HERE.

THERE APPEARS TO BE A SUBTLE BOUNDARY ACROSS CENTRAL TEXAS WITH
NORTH-NORTH EAST WINDS UP TO 10 KTS THAT MAY HELP DRIVE ADDITIONAL
DEVELOPMENT AT WACO THROUGH EARLY EVENING...THEN BECOMING EAST AT
5 KTS THROUGH TONIGHT. MVFR CIGS ARE EXPECTED TO REMAIN SOUTHEAST
OF WACO AFTER SUNRISE WEDNESDAY...AS STRONG BOUNDARY LAYER FLOW
HANGS CLOSE TO THE DISTURBANCE AND THE IMMEDIATE UPPER TEXAS
COAST.

05/

&&

.UPDATE...
THE INHERITED FORECAST IS ON TRACK AND NO SIGNIFICANT CHANGES ARE
NEEDED FOR THE MORNING UPDATE. THE CURRENT MAIN FEATURE OF
INTEREST IS A LOW PRESSURE SYSTEM MOVING WEST ACROSS THE NORTHERN
GULF OF MEXICO. SATELLITE OBSERVATIONS CONFIRM THIS FEATURE IS NOW
SOUTH OF THE SOUTHWEST LOUISIANA COAST BUT A CLOSED SURFACE LOW
CANNOT BE FOUND IN THE SURFACE OBS/ANALYSIS. HOWEVER...THIS LOW
PRESSURE SYSTEM IS INCREASING THE MOISTURE CONTENT ACROSS THE
REGION...AND THE 12Z FWD RAOB ALREADY SHOWS AN INCREASE IN PWATS
FROM 1.27" LAST NIGHT TO 1.51" THIS MORNING. HI-RESOLUTION MODEL
GUIDANCE INDICATES THE MOISTURE WILL INCREASE SLIGHTLY MORE
THROUGHOUT THE AFTERNOON BUT NOT AS MUCH AS PREVIOUSLY THOUGHT.
PREVIOUS MODEL RUNS BROUGHT A BROAD SWATH OF 2" PWATS ACROSS THE
REGION THIS AFTERNOON BUT THE 2" PWATS /WELL ABOVE NORMAL FOR THIS
TIME OF YEAR/ ARE BEING HELD TO OUR SOUTHEAST UNTIL LATER IN THE
WEEK.

REGARDLESS... WITH THE INCREASE IN MOISTURE CONTENT...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON AND DID NOT CHANGE THE POPS FOR THIS AFTERNOON. THIS KEEPS
20 POPS ACROSS THE EAST AND SOUTHEAST WITH A 10 POP/ISOLATED
THUNDERSTORM MENTION ELSEWHERE. RAINFALL TOTALS TODAY WILL RANGE
UP TO HALF AN INCH. ANY THUNDERSTORMS WILL BE CAPABLE OF GUSTY
WINDS AND PERIODS OF HEAVY RAINFALL.

82/JLD

&&

.PREV DISCUSSION... /ISSUED 342 AM CDT TUE AUG 26 2014/
A WEAK TUTT LOW IS CURRENTLY LOCATED OFF OF THE LOUISIANA COAST
AND WILL CONTINUE TO TRACK WESTWARD TODAY. PRECIPITABLE WATER IS
FORECAST TO INCREASE FROM THE RATHER DRY 1.25 INCH READING
RECORDED ON LAST NIGHT/S SOUNDING TO NEAR 2 INCHES BY THIS
AFTERNOON. IN ADDITION...CYCLONIC VORTICITY ADVECTION FROM THE
TUTT LOW/AXIS WILL PROVIDE FORCING FOR ASCENT OVER THE REGION. ALL
MODEL FORECAST SOUNDINGS INDICATE AN AIRMASS THAT IS UNCAPPED AND
CONTAINS WEAK TO MODERATE INSTABILITY THIS AFTERNOON. THE BEST
MOISTURE AND FORCING WILL OCCUR ACROSS THE EASTERN AND
SOUTHEASTERN ZONES WHERE POPS OF 20 PERCENT ARE FORECAST.
HOWEVER WILL CONTINUE TO MENTION ISOLATED CONVECTION WITH A 10 POP
FOR THE REMAINDER OF THE CWA AS HIGH RESOLUTION AND SHORT TERM
GUIDANCE STILL SHOW A FEW SHOWERS/STORMS AFFECTING CENTRAL AND
WESTERN ZONES AS WELL. HIGHS TODAY WILL BE SLIGHTLY COOLER THAN
YESTERDAY DUE TO THE INCREASE IN COLUMN MOISTURE AND WEAK COLD
ADVECTION FROM LOW LEVEL EASTERLY FLOW.

WHILE THE TUTT LOW...WHICH IS AN UPPER LEVEL FEATURE...WILL MOVE
INLAND INTO CENTRAL TEXAS WEDNESDAY...A SURFACE TO MID LEVEL
CYCLONE WILL REMAIN OFF OF THE TEXAS COASTLINE IN THE NW GULF.
MOST MODEL GUIDANCE DOES INDICATE THE SURFACE CYCLONE WILL BECOME
BETTER DEFINED BY WEDNESDAY MORNING. ALTHOUGH A TRANSITION TO A
WARM-CORE OR TROPICAL CYCLONE IS NOT EXPECTED...IT WILL TEND TO
CONSOLIDATE THE BEST MOISTURE NEAR ITS CENTER OVER THE NW GULF
WHICH WILL DIMINISH THE MOISTURE OVER NORTH TEXAS ON WEDNESDAY.
PRECIPITABLE WATER OVER OUR CWA WILL DROP BACK BELOW 1.5 INCHES.
IN ADDITION...MODEL SOUNDINGS INDICATE A WARMING OF TEMPS FROM
600-700MB WHICH SHOULD CAP OFF ANY CONVECTION THAT TRIES TO
DEVELOP. WILL SHOW JUST ISOLATED AFTERNOON SHOWERS/STORMS OVER THE
WESTERN AND SOUTHERN ZONES...WHERE MOISTURE IS HIGHEST AND CIN
WEAKEST...AND A DRY FORECAST ELSEWHERE. OTHERWISE...HIGH TEMPS
WILL MAINTAIN A SLIGHT COOLING TREND DUE TO CONTINUING WEAK COLD
ADVECTION IN EASTERLY LOW LEVEL FLOW.

THE UPPER TROUGH THAT IS NOW DROPPING THROUGH NEVADA WILL BE OUR
PRIMARY RAIN MAKER. THIS FEATURE WILL ARRIVE INTO THE PLAINS ON
THURSDAY WITH THE TROUGH AXIS CROSSING OUR REGION SATURDAY. THIS
UPPER LEVEL SYSTEM WILL DRAW THE RICH GULF MOISTURE ASSOCIATED
WITH THE LOW LEVEL CYCLONE INTO NORTH TEXAS THURSDAY NIGHT WITH
PRECIPITABLE WATER INCREASING TO OVER 2 INCHES. RAIN WILL SPREAD
IN FROM THE SOUTHEAST THURSDAY AFTERNOON ASSOCIATED WITH THE
INFLUX OF HIGH TROPICAL MOISTURE...AND FROM THE WEST THURSDAY
NIGHT FROM CONVECTION BEING FORCED BY THE LEADING EDGE OF THE
UPPER TROUGH. OUR BEST RAIN CHANCES WILL OCCUR FRIDAY AND SATURDAY
WHEN LIFT FROM THE UPPER TROUGH IS CENTERED OVER THE REGION AND
MOISTURE AND INSTABILITY ARE MORE THAN ADEQUATE FOR CONVECTION.
SOME LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH THUNDERSTORMS
BUT OVERALL RAIN AMOUNTS WILL BE HIGHLY VARIABLE FROM LOCATION TO
LOCATION DUE TO THE EXPECTED SCATTERED NATURE OF CONVECTION. HIGH
TEMPERATURES WILL CONTINUE TO COOL INTO THE LOW 90S FOR MOST AREAS
FRIDAY AND SATURDAY DUE TO THE INCREASED CLOUD COVER AND RAINFALL.

THE UPPER TROUGH WILL EXIT THE REGION SUNDAY AND SUBSIDENCE AND
DRYING ALOFT WILL OCCUR FROM WEST TO EAST. WILL KEEP JUST A SLIGHT
CHANCE OF RAIN GOING OVER THE EAST. TEMPERATURES WILL BEGIN TO
WARM UP SUNDAY AND INTO EARLY NEXT WEEK DUE TO INCREASING
SUNSHINE. HOWEVER UPPER LEVEL RIDGING DOES NOT BUILD IN OVER THE
AREA EARLY NEXT WEEK...SO THESE TEMPS WILL JUST BE SLIGHTLY ABOVE
NORMAL FOR EARLY SEPTEMBER.

TR.92



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  99  78  98  76  97 /  10  10   5   5  10
WACO, TX              99  75  98  74  97 /  10  10   5   5  20
PARIS, TX             96  73  94  70  94 /  20  20   5   5  10
DENTON, TX            99  75  97  72  96 /  10  10   5   5  10
MCKINNEY, TX          97  74  96  71  95 /  10  10   5   5  10
DALLAS, TX            99  79  98  77  96 /  10  10   5   5  10
TERRELL, TX           99  75  98  74  96 /  20  20   5   5  10
CORSICANA, TX         99  75  98  74  96 /  20  20   5   5  20
TEMPLE, TX            99  73  98  72  97 /  10  10  10  10  20
MINERAL WELLS, TX    100  72  98  72  96 /  10  10  10   5  10

&&

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

&&

$$

05/82





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