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

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000
FXUS64 KFWD 232106
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
406 PM CDT SAT APR 23 2016

.DISCUSSION...

.SYNOPSIS...
THE PAST COUPLE OF DAYS HAVE BEEN QUIET ACROSS NORTH AND CENTRAL
TEXAS COURTESY OF SURFACE HIGH PRESSURE. THIS IS EXPECTED TO
CHANGE EARLY NEXT WEEK AS THE WEATHER PATTERN BECOMES MORE
CONDUCIVE FOR PRECIPITATION...INCLUDING THE THREAT FOR SEVERE
WEATHER.

&&

.SHORT TERM (TONIGHT THROUGH MONDAY)...
TONIGHT SHOULD BE A RELATIVELY QUIET NIGHT ACROSS MUCH OF NORTH
AND CENTRAL TEXAS AS SHORTWAVE RIDGING AND THE SUBSEQUENT SURFACE
HIGH BOTH SLIDE TOWARDS THE EAST. THE RESULTANT SOUTHERLY FLOW
SHOULD HELP TO ALLOW SOME MOISTURE TO LIFT NORTHWARD...ESPECIALLY
ACROSS SOUTHERN AND WESTERN ZONES. IN GENERAL THIS WILL PROMOTE
NOCTURNAL MIXING AND INCREASE THE CLOUD COVER WHICH SHOULD HELP TO
KEEP OVERNIGHT LOW TEMPERATURES A FEW DEGREES WARMER THAN PREVIOUS
NIGHTS. TONIGHT SHOULD BE DRY...BUT I WOULD NOT BE SURPRISED TO
SEE SOME PATCHY FOG/DRIZZLE...ESPECIALLY ACROSS FAR SOUTHEASTERN
ZONES...BUT BELIEVE THAT THE WINDS MAY REMAIN A BIT TOO STRONG FOR
WIDESPREAD DEVELOPMENT.

FOR SUNDAY AND SUNDAY NIGHT...THE STRENGTHENING SURFACE PRESSURE
GRADIENT IN RESPONSE TO LEE-SIDE CYCLOGENESIS SHOULD RESULT IN
INCREASING SOUTH WINDS WHICH WILL TRANSPORT ADDITIONAL LOW LEVEL
MOISTURE NORTHWARD. THERE APPEARS TO BE A SUBTLE TROUGH THAT
SWINGS THROUGH MUCH OF NORTH AND CENTRAL TEXAS MAINLY DURING THE
FIRST HALF OF THE DAY WHICH MAY RESULT IN ENOUGH LIFT FOR SOME
ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS. RIGHT NOW...WILL
HAVE THE HIGHEST POPS DOWN ALONG AND SOUTH OF THE HIGHWAY 84
CORRIDOR WHERE THE BETTER MOISTURE IS JUXTAPOSED WITH SOME LIFT.
AFTERNOON HIGH TEMPERATURES ON SUNDAY WILL CONTINUE TO MODERATE
WITH THE PERSISTENT SOUTHERLY FLOW AHEAD OF THE SHARPENING
DRYLINE. WHILE INSTABILITY DOES BUILD A BIT AHEAD OF THIS FEATURE
ACROSS OUR NORTHWESTERN ZONES IN THE AFTERNOON...MASS FIELDS
INDICATE THAT A BULK OF THE FORCING FOR ASCENT WILL HAVE DEPARTED
THE REGION. STILL...LOW LEVEL CONVERGENCE ALONG THE DRYLINE MAY BE
ENOUGH TO RESULT IN SOME ATTEMPTS AT CONVECTIVE INITIATION ACROSS
NORTHWESTERN ZONES LATE SUNDAY AFTERNOON.

FOR MONDAY...LOW PRECIPITATION CHANCES WILL CONTINUE AS THE UPPER
AIR PATTERN TRANSITIONS TO MORE OF A ZONAL FLOW ACROSS THE CENTRAL
PLAINS WITH A POTENT UPPER LEVEL TROUGH ACROSS THE FOUR CORNERS
REGION. LOW LEVEL MOISTURE WILL LIFT TOWARDS THE NORTH AND A
DRYLINE WILL GRADUALLY MIX TOWARDS THE EAST MONDAY AFTERNOON.
THERE ARE SOME SLIGHT DISCREPANCIES WITH THE POSITION OF THE
DRYLINE ON MONDAY AFTERNOON HOWEVER. THE ECMWF...NAM AND CANADIAN
ALL KEEP THE DRYLINE OUT WEST ACROSS THE BIG COUNTRY WHILE THE GFS
RAPIDLY MIXES THE BOUNDARY TOWARDS THE HIGHWAY 281 CORRIDOR. GIVEN
THE MODELS BIAS TO TEND TO OVER MIX AND PROGRESS THE DRYLINE
FASTER THUS FAR THIS YEAR...I HAVE SIDED WITH THE
ECMWF/NAM/CANADIAN CAMP ON THE POSITION OF THIS BOUNDARY. WHILE
MUCH OF THE AREA WILL BE BENEATH THE WARM SECTOR...IT APPEARS THAT
A VERY STOUT CAP WILL BE IN PLACE WHICH SHOULD SQUELCH
CONVECTION...ESPECIALLY SINCE THERE APPEARS TO BE NO SOURCE OF
APPRECIABLE SYNOPTIC SCALE LIFT. STILL...ANY MESOSCALE LIFT /I.E.
LOW LEVEL DRYLINE CIRCULATIONS/ MAY BE ENOUGH TO ERODE THE CAP IN
ISOLATED SPOTS. IF STORMS DO DEVELOP...THEY WILL LIKELY BECOME
SEVERE GIVEN THE SHEAR-INSTABILITY SPACE WITH A THREAT MAINLY FOR
LARGE HAIL AND DAMAGING WINDS. AGAIN...THIS RISK IS HIGHLY
CONDITIONAL AND ONLY WARRANTS A 10 POP AT THIS TIME. IT SHOULD BE
NOTED THAT FORECAST SOUNDINGS...MAINLY ACROSS SOUTHEASTERN ZONES
DO REVEAL THAT CONVECTIVE TEMPERATURES ARE REACHED. IF THIS IS THE
CASE AND PARCELS CAN ASCEND FREELY PAST THEIR LFC...THERE WILL BE
A SLIGHTLY HIGHER POTENTIAL FOR SEVERE WEATHER HERE MAINLY IN THE
LATE AFTERNOON HOURS.

&&

.LONG TERM (TUESDAY THROUGH FRIDAY)...
FOR TUESDAY...THE CHANCE FOR PRECIPITATION WILL INCREASE AS THE
UPPER LEVEL LOW GRADUALLY NUDGES TOWARDS THE EAST. CONTINUED
SHARPENING OF THE DRYLINE IS EXPECTED AND THERE WILL BE A SLIGHT
CHANCE FOR SHOWERS AND THUNDERSTORMS LATE IN THE AFTERNOON ALONG
AND NORTHWEST OF A COMANCHE TO FORT WORTH TO SHERMAN LINE.
COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE ISOLATED
TO PERHAPS WIDELY SCATTERED DUE TO 1)...THE VERY STOUT CAP IN
PLACE AND 2)...THE LOCATION OF THE LARGE SCALE ASCENT (LOCATED
FURTHER NORTH INTO OKLAHOMA). IT SHOULD BE NOTED THAT THE LATEST
ECMWF DOES BRING THE LOCATION OF THE TROUGH A BIT FURTHER SOUTH
DOWN TOWARDS OUR NORTHWEST COUNTIES WHICH WOULD CERTAINLY HELP TO
ERODE THE CAP QUICKER AND RESULT IN A MORE FAVORABLE ENVIRONMENT
FOR EARLIER CONVECTIVE INITIATION DURING THE DAY ON TUESDAY.
REGARDLESS...ANY STORM THAT DOES DEVELOP WILL LIKELY BECOME SEVERE
VERY QUICKLY AS FORECAST CAPE VALUES IN EXCESS OF 3500 J/KG AND
DEEP LAYER SHEAR VALUES NEAR 35 KNOTS WILL SUPPORT AN ISOLATED
SUPERCELL THREAT. LIKE MONDAY...THE COVERAGE OF STORMS IS EXPECTED
TO REMAIN LOW DURING THE AFTERNOON HOURS ON TUESDAY.

INTO TUESDAY EVENING AND NIGHT...IT APPEARS THAT MORE ROBUST
FORCING WILL OVERSPREAD NORTH AND CENTRAL TEXAS (30 TO 40 METER
HEIGHT FALLS). THIS MAY FOSTER THE DEVELOPMENT OF ADDITIONAL
THUNDERSTORMS. GIVEN THE AMOUNT OF FORECAST SHEAR...STEEP LAPSE
RATES AND DRY MID-LEVEL AIR...IT APPEARS THAT A COLD POOL MAY
DRIVE A COMPLEX OF STORMS (LIKELY ONE OR TWO BOWING SEGMENTS)
ACROSS THE BIG COUNTRY AND INTO NORTH AND CENTRAL TEXAS. THIS WILL
CERTAINLY SUPPORT A WIDESPREAD DAMAGING WIND THREAT...BUT HAIL
WILL BE POSSIBLE GIVEN THE STEEP LAPSE RATES. BY WEDNESDAY
MORNING...THE ONGOING COMPLEX OF STORMS SHOULD BE PUSHING TOWARDS
OUR EASTERN COUNTIES.

FOR WEDNESDAY...WHAT OCCURS ON WEDNESDAY IS HIGHLY DEPENDENT ON
ACTIVITY THAT GOES ON DURING THE DAY AND EVENING ON TUESDAY. IN
ADDITION...MODELS DIFFER ON THE LOCATION OF THE SYNOPTIC SCALE
FEATURES AS WELL. WHILE MORE PROGRESSIVE WITH THE SURFACE
FEATURES ON MONDAY...THE GFS IS THE LONE MODEL THAT MIXES THE
DRYLINE BACK TOWARDS THE WEST IN THE WAKE OF TUESDAY`S
AFTERNOON/EVENING CONVECTION. THE ECMWF...CANADIAN AND NAM ALL
BLAST THE DRYLINE/FRONTAL BOUNDARY THROUGH A LARGE MAJORITY OF THE
FORECAST AREA. I BELIEVE THAT THIS IS TIED TO THE SPEED/LOCATION
OF THE UPPER LEVEL FORCING TO THE NORTH. THE GFS REMAINS A BIT
SLOWER WITH THE UPPER TROUGH AND LIFTS IT FURTHER TOWARDS THE
NORTH INTO THE HIGH PLAINS...WHILE THE CANADIAN AND THE ECMWF ARE
A BIT QUICKER AND PUSH THE UPPER TROUGH A BIT FURTHER TOWARDS THE
EAST. REGARDLESS OF THE LARGER SYNOPTIC SCALE BACKGROUND...IF A
MORNING COMPLEX OF STORMS DOES DEVELOP...IT SHOULD PRODUCE ENOUGH
MESOSCALE SUBSIDENCE TO KEEP ANY AREAS WEST OF ONGOING PRECIP
STABLE DURING THE LATE MORNING HOURS ON WEDNESDAY.

FOR THE WEDNESDAY AFTERNOON....IF THE ECMWF...CANADIAN...AND NAM
SOLUTIONS ARE CORRECT...THERE WILL NOT BE MUCH IN THE WAY OF
SYNOPTIC SCALE LIFT FOR ANY ADDITIONAL PRECIPITATION. HOWEVER...IF
THE GFS IS CORRECT...THERE MAY BE ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ON WEDNESDAY AFTERNOON AS IT ADVERTISES NEARLY
3000 J/KG OF CAPE WITH 30-35 KNOTS OF DEEP LAYER SHEAR.
UNFORTUNATELY...WILL HAVE TO RELY ON A BLENDED SOLUTION AS THERE
REMAINS TOO MUCH UNCERTAINTY TO SWING EITHER WAY AND WILL KEEP
HIGHEST POPS CONFINED TO FAR EASTERN SECTIONS OF THE FORECAST
AREA.

FOR THURSDAY...THE FORECAST (PRECIP AND TEMPERATURES) REMAINS
QUITE UNCERTAIN AS THE MORE PROGRESSIVE MODEL SOLUTIONS KEEP THE
AREA COOL WITH NORTH FLOW. THE GFS KEEPS THE AREA VERY WARM WITH
CONTINUED SOUTH WINDS. REGARDLESS ALL MODELS DO AGREE THAT
SUBSIDENCE (CHARACTERIZED BY 20 TO 30 M HEIGHT RISES) SHOULD BE
ENOUGH TO KEEP PRECIPITATION CHANCES VERY LOW THURSDAY AFTERNOON.

FOR FRIDAY AND BEYOND...THERE DOES APPEAR TO BE ANOTHER THREAT FOR
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY AS THE NEXT UPPER
TROUGH LIFTS NORTHWARD. THE RESULTANT LEE-SIDE CYCLOGENESIS SHOULD
RESULT IN AN INCREASE IN LOW LEVEL MOISTURE. MODELS DO REMAIN
SPLIT ON THE LOCATION OF THE UPPER TROUGH WITH THE ECMWF BEING
MORE PROGRESSIVE WHILE THE GFS LAGS BEHIND. EITHER WAY...IT DOES
APPEAR THAT THE WEATHER WILL REMAIN ACTIVE TOWARDS FRIDAY AND
SATURDAY.

&&

BAIN

&&

.AVIATION...
/ISSUED 1230 PM CDT SAT APR 23 2016/
/18Z TAFS/

VFR CONDITIONS WILL PREVAIL WITH WINDS LESS THAN 10 KTS TODAY BUT
WIND SPEEDS WILL INCREASE ON SUNDAY.

SOUTH TO SOUTHEAST WINDS WILL OCCUR TODAY AT SPEEDS LESS THAN 10
KTS. A CUMULUS FIELD WITH BASES AROUND 6 KFT WILL CONTINUE TO
INCREASE IN COVERAGE THIS AFTERNOON. AN UPPER LEVEL LOW CURRENTLY
IN UTAH WILL MOVE EAST INTO THE PLAINS ON SUNDAY. THIS WILL RESULT
IN A STRENGTHENING SURFACE PRESSURE GRADIENT AND STRONGER WINDS
ACROSS THE SOUTHERN PLAINS. THE LOW LEVEL JET WILL INCREASE
OVERNIGHT TO AROUND 30 KTS FROM THE SOUTH WHICH MAY RESULT IN SOME
LLWS PROBLEMS SUNDAY MORNING. SURFACE WIND SPEEDS BY MID MORNING
ARE EXPECTED TO BE SUSTAINED AT 15-20 KTS WITH GUSTS NEAR 25 KTS.
A BKN CLOUD DECK WITH CIGS BETWEEN 4-6 KFT CAN BE EXPECTED ON
SUNDAY.

JLDUNN


&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH    60  83  66  83  69 /   5   5  10  10  10
WACO                59  80  65  82  69 /   5  10  10  10  10
PARIS               58  81  62  77  68 /   5   5  10  10  10
DENTON              59  81  64  81  68 /   5   5  10  10  10
MCKINNEY            58  81  64  79  68 /   5   5  10  10  10
DALLAS              62  82  66  83  70 /   5   5  10  10  10
TERRELL             59  82  64  81  69 /   5   5  10  10  10
CORSICANA           59  82  65  81  69 /   5   5  10  10  10
TEMPLE              59  79  65  83  69 /   5  20  20  10  10
MINERAL WELLS       58  86  64  87  68 /   5   5  10  10  10

&&

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

$$

82/15



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