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

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FXUS64 KFWD 261137
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
637 AM CDT SUN APR 26 2015

....POTENTIALLY SIGNIFICANT SEVERE WEATHER POSSIBLE FOR PORTIONS
OF NORTH AND CENTRAL TEXAS TODAY...

.AVIATION...
FIRST CHALLENGE IS IFR STRATUS THAT IS MOVING NORTHWARD FROM
CENTRAL AND SOUTHEAST TEXAS. THIS CLOUD DECK SHOULD AFFECT DAL
AFTER 13Z...AND MAY CLIP GKY/DFW AS WELL. THIS MOISTURE LAYER IS
THIN AND STRATUS SHOULD ERODE BY 15Z OR 16Z.

VERY STEEP LAPSE RATES MOVE INTO THE AREA BY MIDDAY AND THERE IS
ACTUALLY REALLY GOOD MODEL AGREEMENT IN BRINGING A PLUME OF MID
LEVEL MOISTURE AND LIFT INTO THE AREA EARLY-MID AFTERNOON. THIS
SHOULD BE SUFFICIENT FOR HIGH BASED OR ELEVATED THUNDERSTORMS AS
THERE IS ABOUT 400-700 J/KG OF INSTABILITY FROM PARCELS LIFTED
NEAR 12000FT. DRY AIR BELOW THIS ACTIVITY WILL EXIST AND WOULD
ENHANCE TURBULENCE AND SURFACE WIND GUSTS...EVEN IF THERE IS
LITTLE RAINFALL. WILL SHOW A 2 HOUR WINDOW OF VCTS FOR THIS WAVE
OF ACTIVITY FROM 20-22Z...BUT TIMING IS NOT CERTAIN AT THIS POINT.

THE SURFACE AIRMASS WILL CONTINUE TO DESTABILIZE DURING THE LATE
AFTERNOON AND EVENING HOURS AS MOISTURE INCREASES. THIS WILL OPEN
THE DOOR FOR SURFACE BASED CONVECTION MOVING IN FROM THE WEST
AFTER IT FIRES ON THE DRY LINE. CONFIDENCE IS NOT ESPECIALLY HIGH
THAT THIS ROUND OF ACTIVITY WILL IMPACT TAF SITES...BUT SINCE
THERE IS THE POTENTIAL FOR SEVERE STORM WILL SHOW VCTS FROM 00Z TO
04Z. RAIN AND THUNDERSTORM CHANCES INCREASE IN THE LATE EVENING
AND OVERNIGHT HOURS WHEN A MORE SOLID LINE OF STORMS SHOULD
DEVELOP AND MOVE IN FROM THE WEST. THIS IS WHEN UPPER FORCING WILL
BE STRONGEST. WILL SHOW TSRA FROM 4Z-9Z.

AFTER THAT WILL LEAVE THUNDER OUT OF TAFS DUE TO LOW
CONFIDENCE...BUT KEEP SHOWERS MENTIONED WITH MVFR CIGS PREVAILING
BEHIND THE FRONT.

TR.92

&&

.SYNOPSIS...
THE FIRST PORTION OF TODAY WILL BE QUITE SIMILAR TO
SATURDAY...WITH VERY WARM AND PLEASANT CONDITIONS. ONE DIFFERENCE
WILL BE THE INCREASE IN LOW LEVEL MOISTURE IN RESPONSE TO THE
APPROACH OF AN UPPER LEVEL LOW. THIS WILL SET THE STAGE FOR ACTIVE
WEATHER THIS AFTERNOON THROUGH MONDAY...THEREAFTER...A MORE
TRANQUIL PATTERN IS IN STORE FOR NORTH/CENTRAL TEXAS.

&&

.SHORT TERM...
THE MAIN CHALLENGE FOR THE SHORT TERM FORECAST WILL
BE THE POTENTIAL FOR MULTIPLE ROUNDS OF CONVECTION /SOME STRONG TO
SEVERE/ ACROSS THE WESTERN TWO THIRDS OF NORTH/CENTRAL TEXAS. WATER
VAPOR IMAGERY AT THIS HOUR REVEALED THAT THE MAIN UPPER LOW THAT
WILL BE RESPONSIBLE FOR TODAY/S SEVERE WEATHER CHANCES WAS LOCATED
ACROSS SOUTHERN ARIZONA. THIS VERY DYNAMIC TROUGH WILL CONTINUE
TO MOVE EASTWARD BEFORE CLOSING OFF LATER TODAY. LOW LEVEL
MOISTURE WILL CONTINUE TO STREAM NORTHWARD INTO THE AREA BENEATH A
STOUT EML THAT IS SIMULTANEOUSLY ADVECTING EASTWARD OFF OF THE
HIGHER TERRAIN. THE STEEP LAPSE RATES ASSOCIATED WITH THE EML IN
CONJUNCTION WITH THE ASCENT PRODUCED BY THE APPROACHING UPPER
LOW /AS EVIDENCED BY 30 TO 40 METER HEIGHT FALLS/ SHOULD SUPPORT
THE DEVELOPMENT OF ELEVATED CONVECTION MID TO LATE MORNING MAINLY
ALONG AND WEST OF A BOWIE TO GLEN ROSE TO KILLEEN LINE. THE STEEP
LAPSE RATES COMBINED WITH SUFFICIENT EFFECTIVE LAYER SHEAR MAY
SUPPORT A MARGINALLY SEVERE HAIL THREAT IN THE MORNING...SHOULD
STORMS DEVELOP.

DURING THE AFTERNOON HOURS...ADDITIONAL CONVECTION IS EXPECTED TO
DEVELOP AS A 100 KT UPPER LEVEL JET NOSES INTO THE SOUTHERN TX
PANHANDLE AND A VORTICITY LOBE ROTATES AROUND THE BASE OF THE MAIN
TROUGH OUT INTO WESTERN NORTH TEXAS. DURING THIS TIME...THE DRYLINE
WILL CONTINUE TO SHARPEN NEAR THE BIG COUNTRY. THE STRONG
LIFT...DIURNAL HEATING...AND INCREASING MOISTURE SHOULD ERODE
SURFACE BASED CONVECTIVE INHIBITION. VERY HIGH CAPE VALUES ON THE
ORDER OF 2500-3000 J/KG....MID LEVEL LAPSE RATES APPROACHING 8
C/KM AND 0-6 KM BULK SHEAR VALUES ON THE ORDER OF 45 TO 50 KNOTS
WILL EASILY SUPPORT A LARGE AND DAMAGING HAIL THREAT. AS THE
STORMS MOVE EAST AND NORTHEAST...GENERALLY BEYOND A BOWIE TO
MINERAL WELLS TO WACO LINE THIS AFTERNOON...THE LOW LEVEL AIRMASS
WILL BECOME INCREASINGLY DRIER WHICH INCREASES THE POTENTIAL FOR
DESTRUCTIVE STRAIGHT LINE WINDS.

WHILE TORNADOES WILL BE POSSIBLE WITH STORMS NEAR AND JUST EAST OF
THE DRYLINE THIS AFTERNOON...THIS THREAT ACTUALLY INCREASES DURING
THE EARLY EVENING HOURS AS LOW LEVEL WINDS INCREASE AND BACK IN
RESPONSE TO THE UPPER LOW MOVING INTO WEST TEXAS. THIS SHOULD
RESULT IN LARGE HODOGRAPHS WHILE CINH IS STILL LOW. AN ENHANCED
TORNADO RISK MAY DEVELOP ACROSS OUR SOUTHWESTERN ZONES THAT WOULD
INCLUDE THE WACO/TEMPLE/KILLEEN AREAS.

UNLIKE MOST SEVERE EVENTS...WE EXPECT CONVECTION TO CONTINUE TO
FIRE THROUGH THE OVERNIGHT HOURS AS THE UPPER LEVEL LOW REMAINS
SITUATED ACROSS THE REGION. THIS WILL ALSO FOSTER AN INCREASING
HEAVY RAIN THREAT AS CONTINUED ADVECTION OF WARM MOIST AIR INTO
THE REGION IS EXPECTED.

THE BOTTOM LINE IS THAT ALL INTERESTS ACROSS NORTH AND CENTRAL TEXAS
NEED TO PAY PARTICULARLY CLOSE ATTENTION TO WEATHER CONDITIONS TODAY
AS THE POTENTIAL EXISTS FOR HIGH IMPACT SIGNIFICANT SEVERE WEATHER
IN THE FORM OF LARGE HAIL...DESTRUCTIVE WINDS...AND A FEW TORNADOES.

&&

.LONG TERM...
ADDITIONAL CHANCES FOR PRECIPITATION WILL REMAIN ON MONDAY AS THE
CLOSED LOW MEANDERS ACROSS THE REGION. A FRONTAL BOUNDARY WILL
STALL OUT NEAR THE RED RIVER AND MAY EVEN DRIFT SOUTHWARD. STRONG
LOW LEVEL THETA-E ADVECTION WILL CONTINUE TO TRANSPORT WARM MOIST
AIR NORTHWARD INTO PORTIONS OF NORTH/CENTRAL TEXAS. WITH THE LACK
OF A STRONG CAP...EXPECT WIDESPREAD TO NUMEROUS SHOWER AND
THUNDERSTORM ACTIVITY. THE WIDESPREAD NATURE OF SHOWERS AND STORMS
MAY MITIGATE THE LARGER SEVERE WEATHER POTENTIAL ON
MONDAY...EXCEPT ACROSS FAR SOUTHERN ZONES WHERE SOME HEATING WILL
BE POSSIBLE. PERHAPS THE LARGER THREAT WILL BE THE POTENTIAL FOR
HEAVY RAIN ON MONDAY AS PWAT VALUES ARE EXPECTED TO CLIMB TOWARDS
THE 1.15-1.25 INCH RANGE. FOR NOW WILL HOLD OFF ON ANY FLOOD
WATCHES PARTICULARLY FOR THE NORTHERN ZONES UNTIL WE GET CLOSER
TO THE EVENT. RAIN CHANCES SHOULD TAPER OFF BY TUESDAY MORNING AS
THE COLD FRONT PUSHES TOWARDS THE SOUTH AND THE UPPER FORCING
DEPARTS THE REGION. COOLER CONDITIONS CAN BE EXPECTED ON TUESDAY
AND WEDNESDAY WITH LITTLE TO NO CHANCES OF PRECIPITATION AS THE
OMEGA PATTERN ESTABLISHES ITSELF. THE NEXT CHANCE FOR RAIN MAY BE
TOWARDS THE BEGINNING OF MAY.

15-BAIN/TR.92

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  85  61  71  54  64 /  30  70  70  60  20
WACO, TX              86  65  76  54  67 /  30  40  50  40  10
PARIS, TX             85  57  67  53  62 /  30  60  70  70  30
DENTON, TX            84  60  67  52  64 /  30  70  70  60  20
MCKINNEY, TX          84  59  68  53  64 /  30  70  70  70  20
DALLAS, TX            86  61  70  54  64 /  30  60  70  60  20
TERRELL, TX           87  61  71  55  64 /  20  50  70  70  20
CORSICANA, TX         87  65  73  54  65 /  10  30  60  60  20
TEMPLE, TX            86  65  80  54  67 /  30  30  40  40  10
MINERAL WELLS, TX     85  62  74  55  65 /  40  70  60  40  10

&&

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

&&

$$



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