National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS64 KFWD 181727 AAB
AFDFWD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1227 PM CDT SAT MAY 18 2013

.AVIATION...
THE NORTH/CENTRAL TEXAS TAF SITES WILL BE BREEZY AND
VFR THIS AFTERNOON THROUGH LATE TONIGHT. THEN...MVFR CIGS ARE
EXPECTED TO ADVECT ACROSS THE SITES...AROUND 09Z AT KACT AND BY 11Z
ACROSS THE METROPLEX. THIS IS DUE TO A STRENGTHENING LLJ TONIGHT
THAT WILL BE IN THE 40-45 KNOT RANGE LATE TONIGHT THROUGH SUNDAY MORNING.

WINDS ARE EXPECTED TO BE AROUND 18KTS WITH HIGHER GUSTS THIS
AFTERNOON...SLIGHTLY WEAKER THIS EVENING THEN INCREASING BY 06Z TO
17G27KT. WINDS ON SUNDAY SHOULD BE 20G30KTS OR JUST A BIT HIGHER
MIDDAY THROUGH LATE AFTERNOON.

A SHORTWAVE MAY DEVELOP SOME ELEVATED CONVECTION NORTH OF I-20
LATE TONIGHT. DUE TO FORECAST SOUNDING PROFILES...WE HAVE A
CONCERN ABOUT THE POTENTIAL OF HEAT BURSTS RESULTING FROM ANY
ACTIVITY THAT PASSES FAIRLY CLOSE TO THE NORTHERN MOST TAF
SITES...KAFW/KDFW/KDAL.    75

&&

.UPDATE...
12Z FWD SOUNDING SHOWS MOISTURE DEPTH HAS BEEN REDUCED AS COMPARED
TO YESTERDAY...WHICH SHOULD CAUSE DEWPOINTS TO MIX OUT INTO THE
LOW 60S WEST TO MID 60S CENTRAL AND EAST. IN ADDITION...THE LOW
LEVEL THERMAL PROFILE HAS WARMED A FEW DEGREES OVER YESTERDAY
WHICH MEANS HIGH TEMPS WILL BE A COUPLE DEGREES WARMER TODAY FOR
MOST AREAS. LIGHT ECHOES IN THE SOUTHWEST CWA THIS MORNING ARE
ASSOCIATED WITH WEAK MID LEVEL CONVECTION AND PRECIP IS LIKELY NOT
REACHING THE GROUND. PREVIOUS FORECAST WAS GENERALLY ON TRACK AND
A JUST A FEW CHANGES TO HOURLY GRIDS WERE MADE FOR TRENDS.

CONCERNING THE CONVECTIVE POTENTIAL FOR THIS AFTERNOON AND
EVENING...IT STILL APPEARS THE WESTERN AND NORTHWESTERN COUNTIES
HAVE SOME THREAT OF SEVERE STORMS BUT THERE ARE SOME MIXED
SIGNALS IN THE DATA TODAY. THE STRONG CAP WILL CONTINUE TO BE THE
PRIMARY IMPEDANCE FOR CONVECTIVE ACTIVITY. A LOWER MOISTURE DEPTH
MAY RESULT IN DEWPOINTS MIXING OUT MORE THAN FORECAST WHICH WOULD
KEEP CIN VALUES TOO HIGH. THE DRYLINE WILL ALSO BE POSITIONED
FARTHER WEST TODAY AND ALONG A LINE FROM VERNON TO SAN ANGELO.
HOWEVER...THE MODEL DATA IS IN AGREEMENT THAT A WEAK SHORTWAVE
WILL MOVE ACROSS THE NORTHWEST ZONES THIS EVENING AND RESULT IN
HEIGHT FALLS. THIS BIT OF FORCING WOULD HELP TO ERODE THE CAP AND
WOULD FAVOR CONVECTIVE INITIATION OCCURRING TO THE WEST OF THE CWA
LATE THIS AFTERNOON. MID LEVEL WESTERLY WIND FIELDS ARE SLIGHTLY
STRONGER TODAY AND STORMS WOULD HAVE THE POTENTIAL TO MOVE MORE
EASTERLY AND INTO THE WESTERN CWA BY EARLY THIS EVENING. THE RUC
KEEPS ALL ACTIVITY TO OUR WEST...BUT THE HRRR AND 12Z NAM ARE
BRINGING IT INTO THE WESTERN ZONES. SOME OF THE OTHER HI-RES
MODELS ARE NOT EVEN INITIATING...SO AGAIN POPS WILL BE GENERALLY
JUST 20 PERCENT WEST OF A GAINESVILLE TO MINERAL WELLS TO
GOLDTHWAITE DUE TO INITIATION AND STORM MOTION UNCERTAINTIES. DUE
TO STEEP LAPSE RATES...INSTABILITY WILL BE HIGH WITH CAPES LIKELY
OVER 3000 J/KG AT PEAK HEATING...AND THE MAIN SEVERE THREAT IN OUR
CWA WILL BE LARGE HAIL. ACROSS THE CENTRAL AND EASTERN ZONES THE
CAP WILL REMAIN TOO STRONG FOR SURFACE BASED CONVECTION...BUT
THESE AREAS MAY EXPERIENCE SPRINKLES AND GUSTY WINDS FROM STORM
ANVILS LATER THIS EVENING.

TR.92


&&


.SHORT TERM...
A SHORTWAVE DISTURBANCE WAS SEEN VIA WATER VAPOR SATELLITE IMAGERY
EARLY THIS MORNING ROTATING THROUGH CENTRAL/EASTERN NEW MEXICO.
THIS FEATURE WILL EJECT WITHIN INCREASING SOUTHWEST FLOW ALOFT
ACROSS WEST TX/OK BY AFTERNOON. THIS WILL DEEPEN AND MOVE THE
SURFACE DRYLINE INTO THE SOUTH PLAINS BY EARLY EVENING. LIFT FROM
BOTH OF THESE FEATURES WILL COMBINE WITH HIGH TEMPERATURES AROUND
100 DEGREES AND THE RESULTING VERY HIGH INSTABILITY FOR THE
DEVELOPMENT OF A FEW SUPERCELLS LATE IN THE DAY. THIS IS TYPICALLY
THE TIME OF THE YEAR/MID MAY-LATE JUNE/ THAT THE DRYLINE OUT WEST IS
THE MOST ACTIVE...USUALLY PRODUCING DIURNAL SEVERE WEATHER IN THE
LATE AFTERNOONS AND EARLY EVENINGS. EXPECT MORE DISCRETE SUPERCELLS
LATE TODAY AND THIS EVENING IN AND NEAR OUR FAR WESTERN COUNTIES.
CURRENT SHEAR AND BUNKERS METHOD INDICATE THERE WILL BE MORE
STEERING CURRENTS TO THE NORTHEAST VERSUS YESTERDAY WITH UPPER
TROUGH APPROACHING. HOWEVER...AS WITH ANY SUPERCELL DEVIANT
MOTIONS CANNOT BE RULED OUT ONCE ANY MESOCYCLONES DEVELOP WITHIN
THE STORMS THEMSELVES. DESPITE RELATIVELY HIGH LCLS WITH THE HOT
AND UNSTABLE AIRMASS...JUST ABOUT ALL TYPES OF SEVERE WEATHER WILL
BE POSSIBLE WITH THIS ACTIVITY. EXPECT ABOUT 20-30 PERCENT COVERAGE
OF SEVERE STORMS ACROSS THE NORTHWEST COUNTIES. THE INVERSION
STRENGTHENS ONCE AGAIN BY LATE EVENING AND EXPECT THE MAJORITY OF
ACTIVITY TO DIMINISH QUICKLY.

THE NEXT ROUND OF SEVERE WEATHER LATE SUNDAY WILL LIKELY BE MORE
ACROSS THE NORTHERN TIER COUNTIES VERSUS JUST THE WEST...AS A
NEGATIVE TILT SHORTWAVE DISTURBANCE ROTATES ACROSS THE TX/OK
PANHANDLES INTO WESTERN OK/KS. THE SURFACE DRYLINE WILL HAVE A
BETTER PUSH TO EAST ACROSS THOSE AREAS NORTH OF I-20 IN RESPONSE
TO THIS SHORTWAVE. THE HIGHER COVERAGE OF SEVERE WEATHER AND RISK
WILL BE OVER EASTERN OK INTO THE OZARKS...BUT SHOULD ZIPPER A FEW
STORMS SOUTH-SOUTHWEST ACROSS THE RED RIVER BY EVENING. ALL THREATS
WILL BE POSSIBLE ONCE AGAIN.

&&

.CLIMATE...
YESTERDAY (MAY 17) WAS THE FIRST 90-DEGREE DAY AT DFW AIRPORT THIS
YEAR. IT WAS ALSO THE FIRST TIME NORTH TEXAS HAS SEEN 100 DEGREES
IN 2013. GRAHAM HIT 101...AND BRECKENRIDGE PEAKED AT 104.

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  93  73  92  72  91 /   5   5  10  20  10
WACO, TX              92  71  91  73  90 /   5   5  10  10  10
PARIS, TX             88  70  87  68  87 /   5   5   5  20  10
DENTON, TX            93  72  90  72  90 /   5  10  10  20  10
MCKINNEY, TX          90  72  89  71  88 /   5   5   5  20  10
DALLAS, TX            93  73  91  74  91 /   5   5  10  20  10
TERRELL, TX           90  71  90  71  89 /   5   5   5  10  10
CORSICANA, TX         91  71  89  73  90 /   5   5   5  10  10
TEMPLE, TX            92  71  91  72  90 /   5   5  10  10  10
MINERAL WELLS, TX     96  70  94  69  95 /   5  20  20  20  20

&&

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

&&

$$

75/