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

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FXUS64 KFWD 240438
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
1138 PM CDT WED APR 23 2014

.AVIATION...
THUNDERSTORMS HAVE WEAKENED AS EXPECTED THIS EVENING WITH THE
NEAREST ACTIVITY OCCURRING NEAR BOWIE...AND MOVING NORTHEAST.
THERE STILL IS POTENTIAL FOR ELEVATED CONVECTION DURING THE
OVERNIGHT HOURS AS THE LOW LEVEL JET STRENGTHENS TO NEAR 50KT AND
THE UPPER TROUGH AXIS APPROACHES FROM THE WEST. WE WILL MAINTAIN A
VCTS IN METRO-AREA TAFS DURING THE 8-11Z TIMEFRAME WITH ACTIVITY
SHIFTING EAST OF THE AREA THEREAFTER. MVFR CIGS REMAIN IN THE
FORECAST AFTER 11Z...BEFORE SURFACE HEATING AND VEERING WINDS
ALLOW CONDITIONS TO IMPROVE TO VFR BY MIDDAY. OTHERWISE...THE
COLD FRONT IS STILL SLATED TO ADVANCE SOUTHEAST THROUGH THE
METROPLEX 18-19Z THEN WACO 20-21Z THURSDAY.

30

&&

.UPDATE...
FORECAST IS ON TRACK AND NO UPDATE REQUIRED AT THIS TIME.

BASED ON SPOTTER REPORTS AND OBJECTIVE THERMODYNAMIC PARAMETER
ANALYSIS...THE SEVERE THUNDERSTORM IN YOUNG COUNTY IS ELEVATED
ABOVE THE CAP AND THUS WILL CONTINUE TO SUSTAIN ITSELF FOR SOME
TIME. CAPE ABOVE THE CAP IS FAIRLY LIMITED...LIKELY LESS THAN 1000
J/KG. THEREFORE THIS SUPERCELL STORM IS STRUGGLING TO PRODUCE
REALLY LARGE HAIL AS MOST STONES ARE FALLING OUT BEFORE THEY GROW
TOO LARGE...DESPITE THE VERY IMPRESSIVE REFLECTIVITY STRUCTURE IT
HAS DISPLAYED THIS EVENING WHICH IS FOOLING MANY OF THE ALGORITHMS
INTO SUGGESTING IT HAS BASEBALL OR LARGER HAIL. SO FAR REPORTS ARE
MOSTLY NICKEL AND QUARTER SIZE...WITH THE LARGEST REPORT IN ITS
LIFETIME BEING GOLFBALL SIZE. ELEVATED CAPE WILL GET WEAKER THE
FARTHER EAST THIS STORM GETS AND THEREFORE INTENSITY SHOULD
GRADUALLY DIMINISH BELOW SEVERE LEVELS...LIKELY BY THE TIME IT
REACHES WISE COUNTY BUT WE SHALL SEE HOW IT GOES.

WITH SUCH STRONG FORCING APPROACHING THE REGION AHEAD OF THE
SHORTWAVE TROUGH...WE DO EXPECT ADDITIONAL ISOLATED TO SCATTERED
ELEVATED CONVECTION TO DEVELOP AND TRACK THROUGH THE CWA FROM WEST
TO EAST DURING THE LATE EVENING AND OVERNIGHT HOURS. AGAIN...CAPE
ACCESSED BY ANY NEW CONVECTION WILL BE FAIRLY LIMITED...AND THIS
NEW CONVECTION WILL LIKELY NOT DEVELOP INTO SUPERCELLS SO THERE IS
JUST A SMALL HAIL POTENTIAL WITH THIS ACTIVITY. CURRENT POP
CONFIGURATION WITH HIGHEST CHANCES IN THE NORTHWEST AND NORTHERN
ZONES OVERNIGHT LOOKS GOOD.

TR.92

&&

.PREV DISCUSSION... /ISSUED 325 PM CDT WED APR 23 2014/
AN APPROACHING SHORTWAVE IS STILL IN THE FOUR CORNERS AREA AT THIS
TIME...BUT ASCENT IS OCCURRING WELL IN ADVANCE OF THIS FEATURE. A
TROPICAL PLUME OF MOISTURE HAS BEEN STREAMING INTO WEST TEXAS...
WITH PERSISTENT MID CLOUDS...AND HIGH-BASED SHOWERS/STORMS HAVE
BEEN ONGOING SINCE THE MORNING HOURS IN EASTERN PORTIONS OF THE
TEXAS PANHANDLE. LEE SURFACE TROUGHING BELOW HAS QUICKLY
INTENSIFIED THE LOW-LEVEL MOISTURE GRADIENT...AND THIS DRYLINE
WILL BE THE FOCUS FOR MORE WIDESPREAD CONVECTIVE INITIATION LATER
THIS AFTERNOON AS THE MID-LEVEL CLOUDS MOVE AWAY FROM THE UNSTABLE
AREA TO THE EAST OF THE BOUNDARY. OUR AREA OF INTEREST FOR
INITIATION WILL BE GENERALLY FROM VERNON TO ABILENE...WHERE
TEMPERATURES ARE ALREADY IN THE MID 80S WITH DEW POINTS NEAR
60F...WHICH EQUATES TO MLCAPE VALUES NEAR OR IN EXCESS OF
2000J/KG. A CUMULUS FIELD CONTINUES TO INCREASE IN THIS AREA...BUT
ONLY MINIMAL VERTICAL EXTENT IS EVIDENT AT THIS TIME. EXPECT
INITIATION IN WESTERN PORTIONS OF NORTH TEXAS WILL BEGIN BETWEEN 4
AND 6 PM CDT.

INDIVIDUAL CELLS WILL MOVE QUICKLY NORTHEAST...BUT THE ACTIVITY
WILL HAVE A TENDENCY TO GRADUALLY PROPAGATE TO THE EAST...INVADING
THE FWD CWA THIS EVENING. WITH DEEP LAYER SHEAR EXCEEDING 40KTS
AND STEEP MID-LEVEL LAPSE RATES...UPDRAFTS ROOTED IN A VERY
UNSTABLE BOUNDARY LAYER WILL BE ABLE TO QUICKLY PRODUCE LARGE
HAIL. LCL VALUES WILL LIKELY BE TOO HIGH FOR A SIGNIFICANT TORNADO
THREAT. AS THE STORMS MOVE INTO NORTH TEXAS...THEY WILL ENCOUNTER
A STABILIZING BOUNDARY LAYER AND GENERALLY INCREASING CAP
STRENGTH (AND DECREASING HELICITY). THE RESULT WILL BE EITHER:
(1) STEADILY DISSIPATING STORMS... OR (2) STORMS THAT GRADUALLY
SEPARATE FROM THE BOUNDARY LAYER. THE LATTER DOES NOT NECESSARILY
IMPLY A SIGNIFICANT DECREASE IN INTENSITY...WITH STEEP LAPSE RATES
ALOFT MAINTAINING THE POTENTIAL FOR HAIL. THE BULK OF ANY
REMAINING ACTIVITY WILL LIKELY BE ALONG AND NORTH OF THE I-20
CORRIDOR LATE TONIGHT.

THE SHORTWAVE TROUGH AXIS WILL PASS THROUGH THE AREA THURSDAY
WITH ASSOCIATED FRONTAL PASSAGE. SHOWER/STORM CHANCES WILL SHIFT
EAST OF THE I-35 CORRIDOR...THE BACK EDGE GENERALLY COINCIDENT
WITH THE TWO AFOREMENTIONED FEATURES. THE SHORTWAVE WILL BE
POTENT...BUT IT APPEARS THE MAIN FORCING FOR ASCENT BE NORTH OF
THE RED RIVER. THERE WILL REMAIN THE POTENTIAL FOR SMALL HAIL IN
EASTERN ZONES MIDDAY INTO THURSDAY AFTERNOON...BUT THE SEVERE
THREAT APPEARS LOW.

SOUTHERLY FLOW WILL QUICKLY RETURN FRIDAY AS A DRYLINE QUICKLY
DEVELOPS ACROSS WEST TEXAS. THIS WILL BEAR WATCHING FOR
DEVELOPMENT...BUT ANY STORMS SHOULD DISSIPATE LONG BEFORE THEY
COULD REACH NORTH TEXAS. ANOTHER POTENTIAL AREA OF INTEREST WILL
BE THE RETREATING 850MB FRONT...WHICH WILL BE DRAPED WEST-TO-EAST
ACROSS CENTRAL TEXAS...ABOVE A SIGNIFICANT MOISTURE DISCONTINUITY
AT THE SURFACE. WITH MINIMAL CONVERGENCE ALONG THE BOUNDARIES AND
NO UPPER SUPPORT...DID NOT INTRODUCE ANY POPS/WX AT THIS TIME.

A FAR MORE POTENT SYSTEM WILL SWING THROUGH THE INTERMOUNTAIN WEST
ON SATURDAY. A DRYLINE WILL SET UP ACROSS WEST TEXAS ONCE AGAIN.
THE AREA AND TIMING OF CONVECTIVE INITIATION MAY BE SIMILAR TO
TODAY (WEDNESDAY)...WITH ANY POTENTIAL ACTIVITY INVADING NORTH
TEXAS DURING THE EVENING HOURS. THE STORM MODE WILL FAVOR DISCRETE
(POTENTIALLY TORNADIC) SUPERCELLS...BUT THE STORM MOTION MAY KEEP
THE BULK OF THE ACTIVITY WITHIN OKLAHOMA SATURDAY NIGHT. BUT WITH
A VIGOROUS LLJ...THE ACTIVITY MAY HAVE A TENDENCY TO TURN RIGHT
TOWARD NORTH TEXAS. THE LLJ WILL ALSO SERVE TO MAINTAIN A TORNADO
THREAT INTO THE EVENING HOURS. A TRANSITION TO AN MCS WITH AN
ENHANCED WIND THREAT MAY OCCUR AFTER MIDNIGHT.

THE EXTENT OF PRECIPITATION THAT LINGERS SUNDAY MORNING WILL HAVE
A CONSIDERABLE BEARING ON THE EXTENT OF ANY ADDITIONAL SEVERE
WEATHER SUNDAY. A POWERFUL MID-LEVEL JET SWINGING AROUND THE BASE
OF THE MAIN UPPER TROUGH WILL FORCE THE DRYLINE EASTWARD...PERHAPS
AS FAR EAST AS THE I-35 CORRIDOR BY MIDDAY. ADDITIONAL DEVELOPMENT
OF THUNDERSTORMS COULD OCCUR ALONG THE I-35 CORRIDOR SUNDAY
MORNING BUT WOULD MORE LIKELY OCCUR IN EASTERN ZONES DURING THE
AFTERNOON. THE BOUNDARY MAY HANG UP...MAINTAINING THE POTENTIAL
FOR STRONG/SEVERE STORMS THROUGHOUT THE EVENING HOURS SUNDAY.

THE ASSOCIATED FRONT WILL BLOW THROUGH NORTH TEXAS ON MONDAY.
REINFORCING SHOTS OF COOL AIR WILL FOLLOW NEXT WEEK AS THE UPPER
LOW LINGERS IN THE EASTERN CONUS. THIS WILL MEAN LITTLE CHANCE FOR
ADDITIONAL RAINFALL AND PERSISTENT BELOW NORMAL TEMPERATURES.

25



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  67  82  61  85  68 /  30  20   0   0   5
WACO, TX              66  83  60  85  68 /  20  20   5   0  10
PARIS, TX             63  78  55  82  62 /  20  30   5   5   5
DENTON, TX            67  82  55  84  66 /  30  20   0   0   5
MCKINNEY, TX          66  81  52  84  63 /  20  20   0   0   5
DALLAS, TX            67  82  63  84  68 /  20  20   0   0   5
TERRELL, TX           65  81  58  84  65 /  20  20   5   0   5
CORSICANA, TX         65  82  62  84  66 /  20  20   5   0  10
TEMPLE, TX            65  83  61  85  68 /  20  20   5   0  10
MINERAL WELLS, TX     64  83  55  87  66 /  30  10   0   0   5

&&

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

&&

$$

30/92





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