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

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000
FXUS64 KFWD 311736
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
1236 PM CDT TUE MAR 31 2015

.AVIATION...
VFR WITH SOUTH FLOW NEAR 15KT WILL PREVAIL THROUGH THE EVENING.
MAIN REGION OF CONVECTIVE ACTIVITY IS EXPECTED TO OCCUR NEAR THE
RED RIVER VALLEY LATER THIS AFTERNOON AND EVENING...WITH GENERAL
MOTION OF STORM CLUSTERS EAST-SOUTHEAST. THIS ACTIVITY SHOULD STAY
JUST NORTH OF METROPLEX TAF SITES AND WILL LEAVE VCTS OUT OF
TAFS. ANY CONVECTION THAT FIRES WEST OF THE METROPLEX SHOULD BE
FAIRLY ISOLATED AND LIKELY DISSIPATE BEFORE MAKING THE JOURNEY FAR
ENOUGH EAST INTO THE METROPLEX.

OTHERWISE MVFR CIGS ARE EXPECTED TO RETURN TONIGHT BUT RAP
FORECASTS SHOW A MORE SOUTHWESTERLY LOW LEVEL FLOW THAN THE OTHER
MODELS. THIS WOULD KEEP BULK OF STRATUS EAST OF METROPLEX TAF
SITES. WILL SIDE MORE WITH THE OTHER GUIDANCE...BUT GIVEN THE SW
FLOW ABOVE THE SURFACE AND THE DRY AIR IN THIS LAYER...WILL SHOW A
SMALLER WINDOW OF MVFR FOR FTW/AFW LATE TONIGHT AND INTO THE
MORNING WITH ACT/DAL SEEING SEVERAL MORE HOURS OF MVFR CONDITIONS.

CAP LOOKS WEAK ENOUGH TOMORROW AFTERNOON FOR SCATTERED CONVECTION
IN THE VICINITY OF DFW FOR THE EXTENDED TAF.

TR.92

&&



.PREV DISCUSSION... /ISSUED 353 AM CDT TUE MAR 31 2015/

00Z UPPER AIR ANALYSIS SHOWED A PLUME OF STEEP MID-LEVEL LAPSE
RATES IN PLACE OVER MUCH OF THE SOUTHERN PLAINS...LIKELY
ASSOCIATED WITH AN ELEVATED MIXED LAYER (EML). ASIDE FROM STEEP
MID-LEVEL LAPSE RATES...THIS EML ALSO REPRESENTS A FAIRLY STOUT
CAPPING INVERSION IN PLACE OVER THE REGION WITH REGARDS TO SURFACE
BASED CONVECTIVE POTENTIAL INSTABILITY. EARLY MORNING SURFACE
ANALYSIS SHOWED THAT THERE WAS AT LEAST SOME MODEST MOISTURE IN
PLACE BELOW THIS EML CAP...WITH DEW POINTS IN MID 60S ALONG THE
GULF COAST TO THE LOWER 60S ACROSS MOST OF NORTH AND CENTRAL
TEXAS. WATER VAPOR SATELLITE IMAGERY SHOWED A COMPACT UPPER LEVEL
LOW PRESSURE SYSTEM OVER THE BAJA PENINSULA...WITH UPPER LEVEL
RIDGING LOCATED DUE NORTH OF THIS FEATURE...OVER THE NORTHERN
CONUS AND CANADIAN ROCKIES. UPPER LEVEL TROUGHING WAS LOCATED OVER
THE NORTHEASTERN CONUS AND JUST OFF THE COAST OF THE PACIFIC
NORTHWEST. THIS LEFT THE SOUTHERN PLAINS IN WEAK WEST TO NORTHWEST
FLOW ALOFT EARLY THIS MORNING.

TODAY...WITH A STOUT CAP IN PLACE...EXPECT THAT WHEREVER EARLY
MORNING STRATUS WINDS UP...IT WILL BE SLOW TO MIX OUT THIS
MORNING. EXPECT CLOUDS TO EVENTUALLY SCATTER OUT THIS
AFTERNOON...LEAVING PARTLY CLOUDY SKIES IN PLACE FOR MOST
LOCATIONS. THE CAP SHOULD ALSO ENSURE A DRY FORECAST FOR MOST OF
THE CWA TODAY...WITH ATTENTION FOCUSING JUST WEST OF THE CWA AS A
DRYLINE ORGANIZES FROM WICHITA FALLS TO NEAR ABILENE AROUND 21Z.
31/00Z MODEL GUIDANCE CONSISTENTLY ADVERTISES CONVECTION
INITIATION ALONG THE DRYLINE AT OR AROUND 00Z/7PM THIS EVENING.
THE FLOW ALOFT IS GENERALLY OUT OF THE WEST-NORTHWEST AS MENTIONED
ABOVE...SO ANY CONVECTION THAT INITIATES ALONG THE DRYLINE SHOULD
TEND TO MOVE EAST INTO BETTER LOW-LEVEL MOISTURE...BUT ALSO INTO
STRONGER CAPPING ASSOCIATED WITH THE EML. HIGH RESOLUTION
CONVECTION ALLOWING MODELS ALSO INDICATE CONVECTION INITIATION
ALONG THE DRYLINE...BUT GENERALLY FAVOR STORMS DEVELOPING NEAR
ABILENE RATHER THAN NEAR WICHITA FALLS WHICH IS WHAT
GLOBAL/COARSER RESOLUTION MODELS FAVOR. EITHER WAY...THERE
APPEARS TO BE A DECENT CHANCE FOR ISOLATED THUNDERSTORMS TO
DEVELOP ALONG THE DRYLINE WEST OF THE CWA BY LATE THIS
AFTERNOON...MOVING EAST ACROSS WESTERN PORTIONS OF THE CWA THIS
EVENING.

IF STORMS ARE ABLE TO DEVELOP ALONG THE DRYLINE...THEY WILL LIKELY
BE STRONG TO SEVERE WITH MODELS ADVERTISING 1500 TO 2000 J/KG OF
SURFACE BASED CAPE JUST EAST OF THE DRYLINE LATE THIS AFTERNOON.
THE FLOW ALOFT IS NOT OVERLY STRONG HOWEVER...AND DEEP LAYER SHEAR
IS EXPECTED TO BE ON THE ORDER OF 25 TO 30 KTS...WHICH IS MARGINAL
FOR A SUPERCELLULAR STORM MODE. WITH THE DEEP LAYER SHEAR VECTOR
AND FLOW ALOFT ORIENTED PERPENDICULAR TO THE DRYLINE...THE
INITIAL STORM MODE WOULD LIKELY BE DISCRETE...POSSIBLY GROWING
UPSCALE INTO A MULTI-CELL CLUSTER OR LINE A COUPLE OF HOURS AFTER
INITIATION. THINK THAT THE LACK OF STRONGER UPPER LEVEL FORCING
WILL LIMIT THE COVERAGE OF STORMS...SO ONLY WENT WITH A 20 POP
WEST OF INTERSTATE 35 THIS AFTERNOON...AND A 30 POP AFTER SUNSET
TAKING INTO ACCOUNT THE POTENTIAL FOR UPSCALE GROWTH. IT IS
ENTIRELY POSSIBLE THAT THERE WILL NOT BE ENOUGH FORCING ALONG THE
DRYLINE TO GET CONVECTION INITIATED IN THE WARM/MOIST SECTOR TO
THE EAST...SO ALSO KEPT POPS LOW TO ACCOUNT FOR UNCERTAINTY
REGARDING STORMS BEING ABLE TO DEVELOP AND MOVE INTO THE CWA. IF
ORGANIZED STORMS MOVE INTO THE CWA...ANTICIPATE THAT LARGE HAIL
AND LOCALLY DAMAGING WIND GUSTS WILL BE THE PRIMARY HAZARDS. LOW-
LEVEL SHEAR IS EXPECTED TO REMAIN SOMEWHAT WEAK...SO UNLESS A
STRONG DISCRETE SUPERCELL DEVELOPS...THINK THAT THE OVERALL
TORNADO THREAT WILL BE LOW THIS AFTERNOON AND THIS EVENING.

WEDNESDAY...THE BAJA UPPER TROUGH/LOW IS EXPECTED TO MOVE EAST OFF
THE MEXICAN HIGH TERRAIN AND OVER CENTRAL TEXAS TOMORROW
AFTERNOON. MODEL GUIDANCE HAS BEEN TRENDING WEAKER AND WEAKER WITH
THIS SYSTEM AS IT MOVES OVER TEXAS ON WEDNESDAY...SO OVERALL
CONFIDENCE IN SUFFICIENT LIFT TO SUPPORT WIDESPREAD RAIN SHOWERS
AND THUNDERSTORMS OVER THE REGION HAS DIMINISHED. THE BEST FORCING
FOR ASCENT ASSOCIATED WITH THIS UPPER TROUGH IS EXPECTED TO MOVE
OVER THE FAR SOUTHEASTER CWA WEDNESDAY AFTERNOON. WENT AHEAD AND
KEPT POPS IN THE 30 TO 40 PERCENT RANGE EAST OF I-35 AND SOUTH OF
I-20 AS A RESULT...BUT DROPPED POPS INTO THE 20 TO 30 PERCENT
RANGE ELSEWHERE. OVERALL THE ADDITIONAL UPPER LEVEL CLOUD COVER
OUT AHEAD OF THIS SYSTEM APPEARS TO DIMINISH THE POTENTIAL FOR
STRONG SURFACE HEATING...SO CHANCES ARE THAT THE EML CAP WILL
SIMPLY PREVENT THUNDERSTORMS FOR DEVELOPING ACROSS MOST OF THE
CWA. MAY SEE SOME ELEVATED RAIN SHOWERS ACCOMPANY THE PLUME OF
MID-UPPER LEVEL MOISTURE ASSOCIATED WITH THE UPPER TROUGH...BUT
DO NOT THINK ANY ORGANIZED THUNDERSTORM ACTIVITY IS LIKELY NEAR
THE UPPER TROUGH. THE FOCUS FOR THUNDERSTORM ACTIVITY ON WEDNESDAY
WILL LIKELY BE WELL NORTH OF THE CWA...CENTERED OVER THE CENTRAL
PLAINS WHERE A COLD FRONT AND STRONGER UPPER LEVEL FORCING ARE
EXPECTED.

THURSDAY...FOR THE MOST PART ON THURSDAY...UPPER LEVEL FLOW WILL
REMAIN WESTERLY WITH NO OBVIOUS SHORTWAVE TROUGHS UPSTREAM TO
PROVIDE LIFT. THIS GENERALLY FAVORS DRY CONDITIONS ACROSS THE
CWA...AND THAT MAY PAN OUT. HOWEVER...THE COLD FRONT THAT MOVES
SOUTH THROUGH THE CENTRAL PLAINS IS EXPECTED TO MOVE ACROSS
OKLAHOMA THURSDAY...APPROACHING THE RED RIVER BY 00Z/7PM THURSDAY
EVENING. TO THE SOUTH OF THIS FRONT...MODEL GUIDANCE CONSISTENTLY
SHOWS THAT A STRONG DRYLINE WILL MOVE EAST TOWARDS THE INTERSTATE
35 CORRIDOR. WITH PERSISTENT SOUTHERLY FLOW FROM THE PRECEDING 48
HOURS...LOW-LEVEL MOISTURE WILL BE IN PLACE...ALBEIT TRAPPED UNDER
A FAIRLY STRONG INVERSION NEAR THE 825 MB LEVEL. THIS INVERSION IS
THE BASE OF ANOTHER EML THAT MODELS INDICATE WILL ADVECT OVER THE
REGION THURSDAY AFTERNOON. THE COMBINATION OF STEEP MID-LEVEL
LAPSE RATES AND LOW-LEVEL MOISTURE HAS MODELS ADVERTISING ANYWHERE
FROM 2-3000 J/KG OF SURFACE BASED CAPE NEAR THE INTERSTATE 35
CORRIDOR THURSDAY AFTERNOON. THE FLOW ALOFT IS ALSO EXPECTED TO BE
STRONG ON THURSDAY...0-6 KM BULK SHEAR VECTORS FORECAST TO BE
ANYWHERE FROM 40 TO 50 KTS OUT OF THE WEST...ORIENTED
PERPENDICULAR TO THE DRYLINE. WHILE THIS COMBINATION OF PARAMETERS
IS HIGHLY FAVORABLE FOR SUPERCELL THUNDERSTORMS...THE MAIN
FORECAST CHALLENGE IS DETERMINING WHETHER STORMS ARE EVEN POSSIBLE
GIVEN THE LACK OF UPPER LEVEL LIFT/SUPPORT.

CONVECTION ALLOWING GUIDANCE DOES NOT EXTEND OUT FAR ENOUGH TO
RESOLVE CONVECTION INITIATION CHANCES ALONG THE DRYLINE AT THIS
TIME. STANDARD MODEL/CONVECTION PARAMETERIZED GUIDANCE ALL SHOW
THE DRYLINE NEAR THE INTERSTATE 35 CORRIDOR...AND ALL FAIL TO
GENERATE PRECIPITATION THURSDAY AFTERNOON/EVENING ALONG THE
DRYLINE. WHILE THIS SEEMS LIKE A FAIRLY CLEAR CUT MESSAGE...THE
CAP WILL BE TOO STRONG FOR STORMS...THESE MODELS ARE ALSO
ADVERTISING A QUICK INCREASE IN MID-LEVEL RELATIVE HUMIDITY ALONG
THE DRYLINE THURSDAY AFTERNOON. THIS IS LIKELY DUE TO PERSISTENT
LIFT...AND POSSIBLY THE MODELS ACTIVATING THEIR SHALLOW CONVECTION
SCHEMES AHEAD OF THE DRYLINE. THOUGHT THAT THE POTENTIAL FOR
MESOSCALE LIFT ALONG THE DRYLINE WAS SUFFICIENT TO ADVERTISE AT
LEAST A SMALL CHANCE OF THUNDERSTORMS ALONG THE INTERSTATE 35
CORRIDOR THURSDAY AFTERNOON AND EVENING. IF THE CAP IS TOO
STRONG...WE WILL LIKELY JUST SEE SOME SIMPLE CONVECTION
ATTEMPTS/ORPHANED ANVIL CLOUDS ALONG THE DRYLINE THURSDAY
AFTERNOON. HOWEVER WANTED TO AT LEAST ADVERTISE THE CHANCE FOR
STORMS ALONG THE DRYLINE BECAUSE IF ANYTHING DEVELOPS...IT IS VERY
LIKELY TO BECOME SEVERE QUICKLY AND BE CAPABLE OF PRODUCING VERY
LARGE HAIL AND DAMAGING WIND GUSTS. WILL CONTINUE TO KEEP A CLOSE
EYE ON THURSDAY`S DRYLINE. REGARDLESS OF WHAT HAPPENS WITH
THUNDERSTORMS ON THURSDAY...CRITICAL FIRE WEATHER CONDITIONS ARE
POSSIBLE WEST OF THE DRYLINE. THESE CONDITIONS ARE DISCUSSED IN
MORE DETAIL IN THE FIRE WEATHER FORECAST.

THIS WEEKEND...THE CENTRAL PLAINS COLD FRONT IS EXPECTED TO MOVE
SOUTH ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY MORNING. BECAUSE
THIS IS THE MOST STABLE TIME OF DAY...CHANCES ARE THAT THE FRONT
WILL MOVE ACROSS THE CWA WITHOUT ANY THUNDERSTORM ACTIVITY. IF THE
FRONT WERE TO SPEED UP AND MEET THE DRYLINE THURSDAY EVENING...THE
TRIPLE POINT OF DRYLINE/COLD FRONT/WARM SECTOR WOULD BE A VERY
FAVORABLE INITIATION POINT FOR THUNDERSTORM ACTIVITY. AT THIS TIME
IT LOOKS LIKE THE FRONT WILL REMAIN IN OKLAHOMA UNTIL LATE
THURSDAY NIGHT/EARLY FRIDAY MORNING...AFTER THE NEAR SURFACE
ENVIRONMENT IS TOO STABLE FOR THUNDERSTORM INITIATION.

TEMPERATURES ARE EXPECTED TO BE MUCH COOLER BEHIND THE
FRONT...WITH HIGHS TOPPING OUT IN THE MID TO UPPER 60S SATURDAY
AND SUNDAY ACROSS NORTH TEXAS. PRECIPITATION CHANCES INCREASE
QUITE A BIT ON SUNDAY AS GULF MOISTURE SURGES NORTH OVER THE
FRONT. EXPECT MOSTLY RAIN SHOWER ACTIVITY WITH SOME EMBEDDED
THUNDERSTORMS AS LAPSE RATES ALOFT ARE EXPECTED TO BE NEAR MOIST
ADIABATIC...OR JUST BARELY UNSTABLE ENOUGH TO SUPPORT CONVECTIVE
UPDRAFTS.

EARLY NEXT WEEK...A WARM FRONT WILL MOVE NORTH ACROSS THE REGION
SUNDAY EVENING...BRINGING US BACK INTO THE WARM SECTOR BY MONDAY
AFTERNOON. WE ARE EXPECTED TO HAVE STEEPER MID-LEVEL LAPSE RATES
AGAIN WITH GOOD QUALITY LOW-LEVEL MOISTURE IN PLACE. THIS GENERAL
COMBINATION YIELDS A CONDITIONAL THUNDERSTORM THREAT ACROSS THE
CWA DURING THE PEAK HEATING HOURS OF THE DAY FOR MONDAY THROUGH
WEDNESDAY. IT IS TOO EARLY TO DETERMINE THE LIKELIHOOD OF ANY
SEVERE THUNDERSTORM CHANCES...HOWEVER IF THERE IS SUFFICIENT LIFT
EARLY NEXT WEEK...THERE WILL LIKELY BE AN ATTENDANT RISK OF SOME
STRONG/ORGANIZED THUNDERSTORM ACTIVITY. TEMPERATURES WILL LIKELY
BE AT OR ABOVE NORMAL MONDAY THROUGH WEDNESDAY.

CAVANAUGH




&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  82  65  78  65  87 /  10  20  30  10  20
WACO, TX              81  64  78  64  86 /  10  20  30  10  20
PARIS, TX             77  60  76  63  79 /  10  30  30  20  20
DENTON, TX            82  64  78  64  88 /  10  30  20  10  20
MCKINNEY, TX          80  62  78  64  83 /  10  30  30  10  20
DALLAS, TX            82  65  78  65  87 /  10  20  30  10  20
TERRELL, TX           79  62  78  64  83 /  10  20  30  20  20
CORSICANA, TX         79  63  77  64  82 /  10  20  40  20  10
TEMPLE, TX            81  64  78  64  85 /  10  20  40  10  10
MINERAL WELLS, TX     85  62  80  63  93 /  20  30  20  10  10

&&

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

&&

$$

 /


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