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

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FXUS64 KFWD 010903
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
403 AM CDT WED OCT 1 2014

.DISCUSSION...
WATER VAPOR LOOP EARLY THIS MORNING SHOWS A WELL DEFINED SHORTWAVE
TROUGH MOVING OUT OF THE FRONT RANGE OF THE ROCKIES INTO KANSAS AND
NEBRASKA. UPPER LEVEL FORCING AHEAD OF THIS FEATURE IS RESULTING IN
LIFT ACROSS THE SOUTHERN PLAINS...AND WITH A SMALL AMOUNT OF
INSTABILITY ALOFT...SOME ELEVATED CONVECTION HAS DEVELOPED. THE TAIL
END OF THIS ACTIVITY STRETCHES INTO OUR FAR NORTH TEXAS...AND THE NW
ZONES MAY RECEIVE A BRIEF SHOWER EARLY THIS MORNING.

OTHERWISE STRATUS ACROSS CENTRAL TEXAS IS SURGING NORTHWARD INTO THE
THE CWA. THIS STRATUS SHOULD REACH THE I-20 CORRIDOR THIS MORNING
BEFORE IT BEGINS TO MIX OUT. A MOSTLY SUNNY AFTERNOON WILL ALLOW
TEMPERATURES TO ONCE AGAIN WARM INTO THE LOWER 90S FOR MOST OF THE
CWA TODAY...WITH SOME MID 90S IN WESTERN ZONES. THE DRY LINE IN WEST
TEXAS WILL BE ILL-DEFINED TODAY...BUT STILL SOME ISOLATED HIGH-BASED
CONVECTION MAY FORM WEST OF THE CWA IN THE HEAT OF THE AFTERNOON. IF
THIS ACTIVITY DEVELOPS IT COULD IMPACT FAR NORTHWEST ZONES THIS
EVENING. SLIGHTLY BETTER CHANCES OF RAIN WILL OCCUR OVERNIGHT AND
TOWARD MORNING FOR THE NW ZONES AS STRONGER FORCING BEGINS TO ARRIVE
INTO THE REGION...WHICH MAY SPARK SOME ELEVATED STORMS. LOWS TONIGHT
WILL BE UNSEASONABLY WARM AND IN THE 70S COMPLEMENTS OF MODERATE
SOUTHERLY WINDS AND A ROBUST STRATUS INVASION BEFORE DAYBREAK.

THERE IS A BIT OF GOOD NEWS IN THE FORECAST REGARDING THE BADLY
NEEDED RAINFALL CHANCES WITH THE THURSDAY SYSTEM. ALL OF THE MODEL
GUIDANCE HAS SLOWED THE PROGRESSION OF THE SHORTWAVE TROUGH BY ABOUT
6 TO 9 HOURS...AND THEREFORE NOW SHOW THE BEST UPPER LEVEL FORCING
FOR LIFT COINCIDING WITH FRONTAL PASSAGE. YESTERDAY THERE WAS
CONCERN THAT THE LIFT WOULD BE EXITING THE REGION BY THE TIME THE
FRONT ARRIVED. THIS MORE FAVORABLE SETUP WARRANTS INCREASING POPS A
LITTLE MORE...ESPECIALLY FOR THE EASTERN ZONES THURSDAY EVENING.
BEST CHANCES OF RAIN WITH THIS EVENT WILL BE OVER THE EASTERN AREAS.
ONE NOTE REGARDING THE POP FORECAST...THE BEST CHANCES OF CONVECTION
ALONG THE I-35 CORRIDOR LOOK LIKE THEY WILL OCCUR IN THE 4PM TO 9PM
TIME FRAME...AND THEREFORE IT IS BEING SPLIT INTO 2 VERIFICATION
PERIODS. QUITE SIMPLY THIS MEANS THAT IF WE WERE TO FORECAST A
CHANCE OF RAIN FOR THIS ENTIRE EVENT...POPS FOR THE I-35 CORRIDOR
WOULD BE HIGHER THAN BOTH OF THE VALUES FOR THURSDAY AND THURSDAY
NIGHT INDICATE.  THEY ARE ARTIFICIALLY LOWER BECAUSE THERE IS
UNCERTAINTY ON WHICH VERIFICATION WINDOW THE RAIN FALLS IN BECAUSE
IT SO CLOSE TO THE END OF ONE AND THE START OF THE NEXT.

THE FRONT WILL ENTER THE NW ZONES DRY EARLY IN THE AFTERNOON...BUT
CONVECTION WILL BEGIN TO DEVELOP ALONG IT BY 3 PM. THE FRONTAL
PASSAGE AND UPPER FORCING WILL ALSO COINCIDE WITH PEAK HEATING...AND
THEREFORE WILL WORK TO WEAKEN A MODEST CAP OVER THE REGION. TEMPS
WILL BE HOT AGAIN THURSDAY WITH HIGHS IN THE LOW TO MID 90S OVER THE
REGION...AND WITH DEWPOINTS NEAR 70...THIS WILL RESULT IN SURFACE
CAPE OF 1500-2500J/KG. DEEP LAYER SHEAR LOOKS MORE THAN SUFFICIENT
FOR ORGANIZED CONVECTIVE MODES...AND THEREFORE A SEVERE WEATHER
THREAT WILL EXIST THURSDAY AFTERNOON AND EVENING. STORM MODES WILL
LIKELY BE MORE LINEAR ACROSS THE NORTHEAST ZONES...BUT A FEW
DISCRETE SUPERCELLS WILL BE POSSIBLE OVER THE WESTERN AND CENTRAL
ZONES WHERE THE CAP IS STRONGER AND WILL INHIBIT A SOLID LINE FROM
DEVELOPING. THE PRIMARY SEVERE WEATHER THREAT WILL BE HAIL AND
DAMAGING WINDS. LOW LEVEL WINDS APPEAR TOO VEERED AND UNIDIRECTIONAL
TO SUPPORT A TORNADO POTENTIAL WORTH MENTIONING...BUT OF COURSE THIS
IS A NON-ZERO THREAT WHEN SURFACE BASED SUPERCELLS ARE ANTICIPATED.
AGAIN NOT ALL OF THE AREA WILL SEE RAIN AS ACTIVITY WILL BE MORE
ISOLATED IN WESTERN ZONES AND SCATTERED ACROSS CENTRAL ZONES. THOSE
THAT DO SEE THUNDERSTORMS MAY PICK UP AN INCH OF RAINFALL.

COOLER AND MUCH DRIER AIR WILL INVADE THE REGION THURSDAY NIGHT AND
INTO THE DAY ON FRIDAY.  HIGHS WILL BE ABOUT 10 DEGREES COOLER ON
FRIDAY WITH SUNNY SKIES AND VERY LOW HUMIDITY.  THE SURFACE HIGH
WILL SETTLE IN OVER NORTH TEXAS FRIDAY NIGHT...AND WITH CLEAR SKIES
AND DEWPOINTS NEAR 40...THIS WILL ALLOW TEMPS TO PLUMMET INTO THE
40S AND 50S OVER THE AREA. SATURDAY LOOKS VERY NICE WITH LIGHT
WINDS...SUNNY SKIES AND HIGHS AROUND 80. SOUTH WINDS WILL RETURN BY
SATURDAY NIGHT AND THEREFORE IT WILL NOT BE AS COOL. HIGHER MOISTURE
WITH DEWPOINTS IN THE 50S WILL ARRIVE SUNDAY. TEMPERATURES WILL
MODERATE QUICKLY EARLY NEXT WEEK DUE TO THE SOUTHERLY WINDS AND
HIGHER MOISTURE. SOME UPPER 80S AND LOW 90S FOR HIGHS ARE EXPECTED
BY TUESDAY...WITH LOWS AGAIN WARMING INTO THE 60S AND 70S.

THE GFS INDICATES LIGHT QPF OVER THE AREA SUNDAY AND MONDAY...BUT
MODEL SOUNDING SHOW THIS IS JUST A SHALLOW LAYER OF MOISTURE BENEATH
A STRONG INVERSION. RAINFALL LOOKS UNLIKELY...BUT IT IS POSSIBLE
SOME DRIZZLE OR ADVECTION FOG MAY OCCUR. EITHER WAY THE FORECAST
REMAINS DRY AS NORTH TEXAS WILL BE IN STRONG NORTHWEST FLOW ALOFT
WITH THE UPPER ENERGY FOR LIFT REMAINING TO OUR NORTHEAST.

TR.92

&&

.AVIATION...
/ISSUED 1138 PM CDT TUE SEP 30 2014/
THE NAM CONTINUES TO BE MOST AGGRESSIVE WITH THE RETURN OF STRATUS
OVERNIGHT...BUT BEING A BIT OF AN OUTLIER LEADS TO THE BELIEF THAT
IT MAY BE OVERDOING IT. AT THIS TIME...WE ARE LEANING MORE
TOWARDS THE RAP AND GFS SOLUTIONS WHICH INDICATE GOOD NORTHWARD
MOISTURE SURGE WITHIN THE 25KT SOUTHERLY LOW LEVEL JET...BUT
GENERALLY EAST OF THE I-35 CORRIDOR. THIS PLACES THE DALLAS AREA
ON THE WESTERN EDGE OF THE CLOUD DECK FIRST THING IN THE
MORNING...SO WE WILL MAINTAIN THE MVFR CIGS AT KDAL AND KDFW 13Z
UNTIL 16Z. STRATUS SHOULD ARRIVE A FEW HOURS EARLIER AT KACT.

THE REST OF THE TAF PERIOD SHOULD REMAIN VFR. STRATUS WILL LIKELY
RETURN WEDNESDAY NIGHT/THURSDAY MORNING...WITH CONVECTION STILL A
POSSIBILITY THURSDAY AFTERNOON AND EVENING BEYOND THIS TAF SET.

30


&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  93  76  93  63  83 /   5  10  40  20   0
WACO, TX              93  75  95  62  85 /   5   5  30  40   5
PARIS, TX             88  71  90  58  78 /  10  10  50  60   0
DENTON, TX            93  73  92  57  81 /   5  10  40  10   0
MCKINNEY, TX          92  73  92  59  82 /   5  10  50  30   0
DALLAS, TX            93  76  93  63  83 /   5   5  40  30   0
TERRELL, TX           93  75  93  62  83 /   5   5  40  50   0
CORSICANA, TX         93  75  93  64  83 /  10   5  30  60   5
TEMPLE, TX            92  74  94  63  85 /   5   5  20  40   5
MINERAL WELLS, TX     94  73  92  56  83 /   5  10  30   5   0

&&

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

&&

$$




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