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

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FXUS64 KFWD 042020
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
320 PM CDT SAT JUL 4 2015

.DISCUSSION...

EARLY AFTERNOON REGIONAL RADARS OBSERVED SOME ISOLATED RAIN
SHOWERS DEVELOPING ALONG THE RED RIVER...AND SOUTH NEAR A LINE
FROM COPPERAS COVE TO CENTERVILLE ACROSS CENTRAL TEXAS. THE GOOD
NEWS FOR THIS EVENING`S INDEPENDENCE DAY FESTIVITIES IS THAT
SATELLITE...SURFACE...AND RADAR DATA DO NOT INDICATE ANY SOURCE OF
ORGANIZED LIFT TO SUPPORT THESE ISOLATED SHOWERS. WITHOUT AN
OBVIOUS SOURCE OF LIFT...ASSUME BUOYANCY IS PROVIDING THE PRIMARY
MEANS OF CONVECTION INITIATION...AND BUOYANCY WILL DIMINISH
QUICKLY JUST BEFORE SUNSET AS THE SURFACE HEATING BUDGET TURNS
OVER TO COOLING VERSUS WARMING.

THROUGH THIS AFTERNOON...EXTENDED THE COVERAGE OF 20 POPS TO
INCLUDE COUNTIES RIGHT ALONG THE RED RIVER TO ACCOUNT FOR THE
ISOLATED SHOWERS AND POSSIBLE STORMS DEVELOPING AT 230 PM CDT.
LEFT IN THE 20 POPS ACROSS THE FAR SOUTHERN CWA IN CENTRAL TEXAS
AS ISOLATED SHOWERS AND THUNDERSTORMS WERE DEVELOPING SOUTH AND
SOUTHEAST OF THE CWA TO THE GULF COAST. LEFT THE HIGHEST POPS IN
THE FAR NORTHEASTERN CWA FROM PARIS TO SULPHUR SPRINGS AS OUTFLOW
FROM THE PERSISTENT MULTI-CELLULAR CONVECTION NEAR ARKLATEX HAS
LEFT AN OUTFLOW BOUNDARY RIGHT AT THE LAMAR/RED RIVER COUNTY LINE.
SOUTHWESTERLY FLOW IMPINGING UPON THIS OUTFLOW BOUNDARY HAS BEEN
CAUSING A REGENERATION OF STORMS FOR A COUPLE OF HOURS NOW...AND
THIS ACTIVITY MAY CONTINUE TO BACK BUILD OVER LAMAR...DELTA...AND
HOPKINS COUNTIES THROUGH THIS EVENING. LEFT 10 POPS IN PLACE FOR
MOST OTHER AREAS AS A "POP-UP" SHOWER OR THUNDERSTORM DRIVEN BY
THE HEATING OF THE DAY/BUOYANCY IS HARD TO RULE OUT JUST ABOUT
ANYWHERE ACROSS NORTH AND CENTRAL TEXAS THROUGH 7 PM.

FOR THIS EVENING...THINK THAT ANY BUOYANCY DRIVEN ISOLATED SHOWERS
AND STORMS WILL TEND TO DISSIPATE QUICKLY AS WE APPROACH
SUNSET...BEFORE 9 PM. THE MAIN AREA OF CONCERN FOR WHERE
THUNDERSTORMS COULD INTERRUPT EVENING INDEPENDENCE DAY ACTIVITIES
IS IN THE FAR NORTHEASTERN CWA...EAST OF A BONHAM TO GREENVILLE TO
EMORY LINE. IF CONVECTION CONTINUES TO BACK BUILD FROM RED RIVER
COUNTY...IT MAY CONTINUE FOR A COUPLE OF HOURS PAST SUNSET. THINK
THAT WITH SUBSIDENCE WORKING ITS WAY OVER THE REGION IN
GENERAL...THAT A LOT OF THIS ONGOING ACTIVITY WILL WEAKEN AND
DISSIPATE WITH THE LOSS OF DAYTIME HEATING. WILL ONLY CARRY 20
POPS THIS EVENING AS A RESULT. THINK MOST LOCATIONS WILL REMAIN
DRY THIS EVENING...AND MOST INDEPENDENCE DAY CELEBRATIONS SHOULD
BE ABLE TO COMMENCE WITHOUT DELAY OR INTERRUPTION FROM
THUNDERSTORM ACTIVITY.

SUNDAY...MANY OF THE CONVECTION PARAMETERIZING MODELS CONTINUE TO
ADVERTISE QPF OVER LARGE PORTIONS OF THE CWA ON SUNDAY. AT THIS
TIME...SIMPLY WENT AHEAD WITH 10 POPS IN THE FORECAST FOR MOST OF
THE CWA AS AN ORGANIZED LIFTING MECHANISM WAS DIFFICULT TO PIN
POINT IN ANY OF THE MODEL DATA. WATER VAPOR SATELLITE IMAGERY DOES
SHOW A SERIES OF WEAK SHORTWAVE TROUGHS EMBEDDED IN NORTHWEST FLOW
IN PLACE OVER THE NORTHERN AND CENTRAL PLAINS...HOWEVER THE UPPER
LEVEL RIDGE IN PLACE OVER FAR WEST TEXAS AND NEW MEXICO APPEARS TO
BE LARGE ENOUGH TO KEEP THIS ENERGY EAST OF NORTH TEXAS. THINK
THAT MOST AREAS WILL REMAIN DRY ON SUNDAY WITH WEAK UPPER LEVEL
RIDGING IN PLACE.

IF THE ONGOING MULTI-CELLULAR CONVECTION SIMPLY CONTINUES TO
REGENERATE STORMS THROUGH THIS EVENING...IT MAY LEAVE A STRONG
ENOUGH COLD POOL IN PLACE TO MAINTAIN A BOUNDARY OVER THE FAR
EASTERN CWA FOR SUNDAY. IF A COHERENT BOUNDARY IS IN PLACE OVER
THE EASTERN CWA TOMORROW...THE LIFT WOULD TEND TO BE ON THE
WESTERN SIDE OF THIS BOUNDARY AS OUR CWA WOULD REPRESENT THE
WARMER SIDE OF THIS WEAK FRONT. LEFT SOME 20 POPS IN PLACE ALONG A
LINE FROM BONHAM TO EMORY TO HEARNE TO ACCOUNT FOR THIS
POSSIBILITY. HOWEVER...IF NO BOUNDARY IS IN PLACE...MAY BE ABLE TO
LOWER THESE POPS TOMORROW. ONCE AGAIN IT WILL BE DIFFICULT TO RULE
OUT THE POSSIBILITY OF ISOLATED AIR MASS THUNDERSTORMS DEVELOPING
DURING THE PEAK HEATING HOURS OF THE DAY JUST ABOUT ANYWHERE
ACROSS THE CWA...SO LEFT 10 POPS IN PLACE AS MENTIONED ABOVE.

A STRONG UPPER TROUGH IS EXPECTED TO MOVE EAST ACROSS THE NORTHERN
PLAINS ON MONDAY...SENDING A COLD FRONT SOUTH ACROSS THE CENTRAL
PLAINS. DURING THE DAY ON MONDAY...THIS TROUGH IS ONLY EXPECTED TO
SEND A SHORTWAVE RIDGE OVER NORTH AND CENTRAL TEXAS. THIS FORCING
FOR SUBSIDENCE SHOULD KEEP THE CWA DRY ON MONDAY. BY MONDAY
NIGHT...MOST MODEL GUIDANCE INDICATES THAT THE COLD FRONT WILL BE
LINED UP WITH NUMEROUS SHOWERS AND THUNDERSTORMS. THESE STORMS
SHOULD ONLY ADD RAIN COOLED AIR TO THE COLD FRONT...WHICH SHOULD
HELP SEND THE FRONT FARTHER SOUTH INTO THE SOUTHERN PLAINS MONDAY
NIGHT INTO TUESDAY MORNING. DEPENDING ON HOW STRONG THE STORMS ARE
ALONG THIS FRONT...THIS FRONT MAY BRING SOME SHOWERS AND
THUNDERSTORMS OVER THE NORTHWESTERN PORTIONS OF THE CWA MONDAY
NIGHT. IF THE FRONT DOES MAKE IT INTO NORTH TEXAS ON TUESDAY...IT
WILL PROBABLY STALL OUT AND PROVIDE A FOCUS FOR SCATTERED
THUNDERSTORM REDEVELOPMENT FROM TUESDAY AFTERNOON THROUGH
WEDNESDAY AFTERNOON.

AT THIS TIME KEPT POPS IN THE 30 TO 40 PERCENT RANGE...SLIGHTLY
BELOW GUIDANCE...BECAUSE CONFIDENCE IN THE FRONT MAKING IT INTO
THE CWA IS NOT OVERLY HIGH. MODELS INDICATE THAT THE UPPER LEVEL
SUPPORT THAT DRIVES THE FRONT SOUTH MOVES OFF TO THE EAST BY
MONDAY NIGHT. IT SEEMS LIKE MODELS ARE BASICALLY RELYING ON THE
STRENGTH AND COVERAGE OF CONVECTION ALONG THE FRONT TO DRAG IT
SOUTH ACROSS NORTH TEXAS. THIS IS CERTAINLY A VALID
SOLUTION...STRONG CONSOLIDATED COLD POOLS OFTEN TIMES ACT JUST
LIKE SYNOPTIC COLD FRONTS. THE MAIN REASON CONFIDENCE IN THIS
SOLUTION IS NOT OVERLY HIGH IS BECAUSE THE MODELS THAT ARE
ADVERTISING THIS SOLUTION DO NOT EXPLICITLY FORECAST
CONVECTION...BUT RATHER PARAMETERIZE CONVECTION TO SAVE
COMPUTATION TIME.

CONVECTION IS COMPLEX...AND IF THE FRONT DOES NOT HAVE AS MANY
STORMS ALONG IT AS MODELS ARE INDICATING AT THIS TIME...IT MAY
STALL OUT NORTHWEST OF THE CWA. IF THAT OCCURS...OUR RAIN CHANCES
WOULD BE MUCH LOWER THAN ADVERTISED. CAN NOT IGNORE THE FACT THAT
THE GFS/ECMWF/CANADIAN ALL BRING THIS FRONT INTO NORTH TEXAS...SO
WILL CONTINUE TO SIDE WITH THIS CONSENSUS UNLESS OBSERVATION
DATA...I.E. A SPARSE COVERAGE OF STORMS ALONG THE FRONT
UPSTREAM...INDICATES OTHERWISE. ASSUMING THE FRONT MAKES IT TO
NORTH TEXAS...ASIDE FROM SCATTERED THUNDERSTORMS TUESDAY AND
WEDNESDAY...TEMPERATURES SHOULD REMAIN IN THE UPPER 80S TO LOWER
90S FOR MOST LOCATIONS.

THURSDAY THROUGH SUNDAY...THE CONSENSUS OF GUIDANCE INDICATES THAT
UPPER LEVEL RIDGING WILL BUILD UP OVER THE SOUTHERN PLAINS.
ASSUMING UPPER LEVEL RIDGING STRENGTHENS OVER THE REGION DURING
THIS PERIOD AS ADVERTISED...WE SHOULD REMAIN DRY WHILE HEAT BUILDS
UP THROUGH THE WEEKEND. WILL LIKELY SEE SOME 100 DEGREE READINGS
WEST OF INTERSTATE 35 NEXT WEEKEND WHERE LOW-LEVEL MOISTURE IS
EXPECTED TO MIX OUT THE MOST. THE REMAINDER OF THE CWA SHOULD SEE
HIGHS START OUT IN THE MID 90S...CLIMBING INTO THE UPPER 90S.

CAVANAUGH

&&

.AVIATION...
/ISSUED 1235 PM CDT SAT JUL 4 2015/

CONCERNS...AFTERNOON CONVECTION NEAR/EAST OF THE METROPLEX AND
MVFR CIGS.

MVFR CIGS CURRENTLY AT KACT SHOULD LIFT AND GIVE WAY TO VFR
CONDITIONS SOON...BUT ANOTHER BRIEF ROUND IS POSSIBLE SUNDAY
MORNING AT KACT AND ACROSS THE CENTRAL AND EASTERN PORTIONS OF THE
METROPLEX.

ISOLATED TO WIDELY SCATTERED AFTERNOON CONVECTION SHOULD DEVELOP
MAINLY EAST OF THE I-35/35E CORRIDOR THIS AFTERNOON.
HOWEVER...MORNING CONVECTION REVEALED AN AREA OF CONVERGENCE ALONG
AND JUST NORTH OF I-30...EAST OF KDFW...THAT MAY DEVELOP A FEW
CELLS AROUND THE METROPLEX MID TO LATE AFTERNOON. THUS HAVE
RETAINED THE VCTS FOR THE 21-00Z TIME PERIOD.

SOUTHERLY WINDS AT 10-15 KNOTS SHOULD CONTINUE THROUGH THE
FORECAST.   75


&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  76  93  77  93  77 /  10  10   5   5  10
WACO, TX              75  92  75  93  76 /  10  10   5   5   5
PARIS, TX             73  89  74  90  75 /  20  20  10  10  10
DENTON, TX            75  92  75  93  76 /  10  10   5   5  10
MCKINNEY, TX          75  91  75  91  76 /  10  10   5   5  10
DALLAS, TX            77  94  77  94  77 /  10  10   5   5  10
TERRELL, TX           75  90  75  92  76 /  10  10   5   5  10
CORSICANA, TX         75  92  75  92  76 /  10  10   5   5   5
TEMPLE, TX            74  91  74  92  76 /  10  10   5   5   5
MINERAL WELLS, TX     74  92  74  93  75 /  10  10   5   5  10

&&

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

&&

$$



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