000
FXUS64 KFWD 132316 AAA
AFDFWD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
616 PM CDT MON MAY 13 2013

.AVIATION...

CONCERNS...NONE.

ALL TAF SITES WILL HAVE SOUTHERLY WINDS GENERALLY 7-16KTS AND VFR
CONDITIONS THROUGH THIS FORECAST.

LOW LEVEL MOISTURE WILL BE INCREASING WITH TIME ACROSS THE REGION
AND DO NOT EXPECT MVFR CIGS AT KACT OR ACROSS THE METROPLEX UNTIL
AFTER 15/06Z (LATE TUESDAY NIGHT/WEDNESDAY MORNING).

NEXT CHANCE FOR CONVECTION IMPACTS WILL BE ON WEDNESDAY LATE
AFTERNOON AND OVERNIGHT. 75

&&

.PREV DISCUSSION... /ISSUED 358 PM CDT MON MAY 13 2013/
SOUTHERLY WINDS ARE RETURNING GULF MOISTURE TO THE REGION. DESPITE
TEMPERATURES WELL INTO THE 80S...DEW POINTS ALONG THE I-35
CORRIDOR HAVE MANAGED TO CLIMB TO NEAR 50 DEGREES. IN WESTERN
ZONES...WHERE MIXING DEPTHS HAVE APPROACHED 10KFT...SURFACE
MOISTURE REMAINS SCANT. IN THE FAR WEST...WHERE THE DROUGHT
REMAINS THE MOST INTENSE...A BIT OF A WESTERLY COMPONENT TO THE
SURFACE WINDS HAS ALLOWED TEMPERATURES TO REACH THE 90S AT
BRECKENRIDGE AND GRAHAM.

MOISTURE WILL CONTINUE TO INCREASE OVERNIGHT AND INTO TUESDAY AS
THE CUT-OFF LOW TO OUR WEST BEGINS TO EJECT. CURRENT WATER VAPOR
SHOWS THAT THE BLOCKING RIDGE ACROSS THE WESTERN STATES IS LOSING
AMPLITUDE...WHICH WILL ALLOW THE CUT-OFF TO RE-JOIN THE POLAR
FLOW. ALTHOUGH THERE IS TYPICALLY CONSIDERABLE DISPARITY AMONG
GUIDANCE WITH THE EVOLUTION OF AN EJECTING CUT-OFF...OPERATIONAL
SOLUTIONS (AND THEIR ENSEMBLE MEMBERS) HAVE MINIMAL SPREAD.
HOWEVER...THE SUBTLE DIFFERENCES WITH ITS FINAL EXIT OUT OF TEXAS
HAVE LED TO A STRIKING SPREAD AMONG GUIDANCE QPF. INTER-OFFICE
CONSENSUS FAVORS A MORE PROGRESSIVE EVOLUTION...WHICH SHOULD
RESULT IN A SHORTER DURATION RAIN EVENT AND LOWER RAINFALL TOTALS
OVERALL. OUR FORECAST MEDIAN STORM TOTALS ARE UNDER 1/2 INCH...
BUT AS WITH CONVECTIVE ACTIVITY...AMOUNTS WILL VARY CONSIDERABLY.

THE MAIN EVENT WILL BE DURING THE DAY WEDNESDAY. THE INCREASED
CLOUD COVER AND ANY ONGOING NOCTURNAL CONVECTION EARLY WEDNESDAY
MAY LIMIT SURFACE-BASED INSTABILITY...BUT STILL ANTICIPATE SOME
AREAS WILL SEE MLCAPE VALUES REACH 2000 J/KG...PRIMARILY WEST.
CONVECTIVE CELLS WILL ENCOUNTER FAVORABLE MID-LEVEL LAPSE RATES
WITH SYNOPTIC-SCALE FORCING...BUT EXPECT WEAK FLOW ALOFT WILL
LIMIT THE DURATION (AND THUS INTENSITY) OF INDIVIDUAL UPDRAFTS.
NONETHELESS...A FEW STORMS MAY BECOME BRIEFLY SEVERE...PRODUCING
LARGE HAIL AND DAMAGING WINDS. WITHOUT ANY SURFACE FOCUS...THE
EVOLUTION OF DEVELOPMENT WILL BE GOVERNED BY THE UPPER FORCING AS
IT SPREADS FROM SOUTHWEST TO NORTHEAST LATE TUESDAY INTO
WEDNESDAY.

A BRIEF PERIOD OF RIDGING ALOFT WILL DOMINATE LATE IN THE WEEK...
BUT THE NEXT TROUGH WILL QUICKLY SWING THROUGH THE INTERMOUNTAIN
WEST. IN RESPONSE TO THE INCREASING FLOW ABOVE THE HIGH PLAINS...
LEE TROUGHING IN THE LOW-LEVELS WILL HELP DEVELOP A DRYLINE ACROSS
WEST TEXAS AS EARLY AS SATURDAY. THE ECMWF CONTINUES TO BE BULLISH
WITH THE DRYLINE CONVECTION SATURDAY AFTERNOON...IMPACTING OUR
WESTERN ZONES. CONSIDERING THE FLOW ALOFT...THINK THE ECMWF
PLACEMENT OF THE DRYLINE IS A BIT TOO FAR EAST BUT WILL MAINTAIN
SOME SLIGHT CHANCE POPS ACROSS FAR WESTERN ZONES FOR ANY STORMS
THAT MIGHT MOVE NORTHEAST INTO OUR CWA.

A COLD FRONT MAY IMPINGE ON THE CWA SUNDAY...AS ITS ASSOCIATED
TROUGH SWINGS PAST TO OUR NORTH. HAVE MAINTAINED SOME LOW END POPS
FOR THIS EVENT. DOWNGLIDE IN NORTHWEST FLOW WILL ENSUE SUNDAY
NIGHT. THE GFS IS INCLINED TO SURGE THE FRONT DEEP INTO THE CWA
AT THAT POINT. BUT EVEN WITH NORTHWEST FLOW ALOFT...WEAK LATE
SEASON COLD FRONTS CAN HAVE A DIFFICULT TIME GETTING INTO NORTH
TEXAS. WITH A WELL MODIFIED AIR MASS BEHIND IT...EXPECT THE
BOUNDARY WILL HANG UP NORTHWEST OF THE CWA. REGARDLESS...THE
PREVAILING NORTHWEST FLOW COULD YIELD MULTIPLE DAYS WITH
NOCTURNAL MCS ACTIVITY CLIPPING OUR NORTHEAST COUNTIES AROUND
DAYBREAK.    25

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  61  86  66  80  66 /   0   5  40  50  30
WACO, TX              59  85  65  80  67 /   5  10  40  50  20
PARIS, TX             58  84  60  75  61 /   0   5  20  50  40
DENTON, TX            60  85  66  80  66 /   0   5  30  50  40
MCKINNEY, TX          57  84  64  78  64 /   0   5  30  50  40
DALLAS, TX            63  86  66  79  66 /   0   5  40  50  30
TERRELL, TX           58  83  63  77  63 /   0   5  30  50  40
CORSICANA, TX         59  83  63  78  64 /   0   5  30  50  30
TEMPLE, TX            58  83  65  79  66 /   5  20  40  50  20
MINERAL WELLS, TX     58  85  64  82  66 /   0   5  40  40  20

&&

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

&&

$$

75/