Severe Thunderstorm Warning 233, NWS Fort Worth, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
1229 PM CDT THU OCT 2 2014

.AVIATION...
HI RES MODELS STILL FORECAST THE POSSIBILITY OF ISOLATED STORMS
BEFORE THE MAIN FEATURE...SO WILL LEAVE THE VCTS IN FOR EARLY
AFTERNOON. BEST TIMING STILL APPEARS TO BE 20Z-22Z IN METROPLEX
AND AN HOUR LATER IN WACO. STORMS WILL PUSH ON OUT QUICKLY AND
THEN NORTH WINDS AND CLEAR SKIES ARE EXPECTED FOR REST OF TAF
PERIOD. 84

&&

.UPDATE...
A STRONG SHORTWAVE TROUGH CONTINUES TO ROTATING EAST-SOUTHEAST
ACROSS THE TX/OK PANHANDLES LATE THIS MORNING...WITH A PRE-FRONTAL
SURFACE TROUGH NOW SWEEPING THROUGH AREAS FROM WICHITA FALLS TO
NEAR ABILENE. THE TRUE COLD FRONT REMAINS FURTHER WEST FROM VERNON
TO SWEETWATER/SNYDER AREAS PER CAA NOTED AND TEMPERATURES FALLING
THROUGH THE 60S INTO THE 50S ACROSS THE TX PANHANDLE. THERMODYNAMICALLY
THE 12Z FWD SOUNDING HAD A MODEST CAP WITH STEEP LAPSE RATES NOTED
BETWEEN 650-800MB. THE CAP SHOULD CONTINUE TO LIFT...MOISTEN AND
WEAKEN WITH THE APPROACH OF THE STRONG LARGE-SCALE ASCENT FROM THE
NORTHWEST BY EARLY-MID AFTERNOON.

UNTIL THEN...A FEW SHOWERS AND NON-SEVERE STORMS WILL CONTINUE
UNDERNEATH THE LIFTING CAPPING INVERSION FROM JUST WEST THROUGH
NORTHEAST OF THE IMMEDIATE DFW METRO AREA. THE ACTION AREA
THROUGH 19Z OR SO WILL BE ACROSS OUR OUR NORTHWEST COUNTIES
THROUGH EARLY AFTERNOON...AS THIS WILL BE WHERE THE STRONGEST
ASCENT AND BREAKING OF THE CAPPING INVERSION OCCURS WITH THE
ARRIVAL OF THE PRE-FRONTAL SURFACE TROUGH. A FEW DISCRETE STRONG
TO SEVERE STORM WILL LIKELY FORM ON THIS FEATURE. THE COLD FRONT
WILL LIKELY SPEED UP AND TAKE OVER THIS SURFACE TROUGH FROM NEAR
HAMILTON UP THROUGH DALLAS-FORT WORTH...AND TOWARD GAINESVILLE AND
SHERMAN BY MID AFTERNOON. AS THIS OCCURS SIMULTANEOUSLY WITH THE
ARRIVE OF THE VIGOROUS SHORTWAVE DISTURBANCE...EXPECT A RAPID
INCREASE OF STORMS TO ZIPPER SOUTHWEST AS FAR SOUTH AS HAMILTON TO
WACO AND POSSIBLY BELL COUNTY. WITH THESE TRENDS IN MIND...HAVE
DRUG THE HIGHER CHANCE TO LIKELY POPS DOWN INTO PARTS OF CENTRAL
TEXAS AS WELL FOR THE LATER AFTERNOON HOURS.

THE MAIN SEVERE THREATS STILL APPEAR TO BE HAIL...DAMAGING WINDS
TO 70 MPH AND FREQUENT LIGHTNING...THOUGH EARLY ON THE EVENT WHEN
STORMS ARE MORE DISCRETE YOU CANNOT RULE OUT A BRIEF TORNADO WITH
ANY OUTFLOW BOUNDARY INTERACTIONS. HAVE HELD ONTO TRENDS FOR THE
EVENING INTO THE OVERNIGHT HOURS WITH NO CHANGES...AS THE FRONT
AND SYSTEM MOVE PROGRESSIVELY ACROSS THE REGION. WITH MORE CLOUD
COVER THAN EXPECTED IN THE WARM SECTOR AND A SLIGHTLY FASTER
ARRIVAL OF THE COLD FRONT...I LOWERED HIGH TEMPS ACROSS THE FAR
WEST AND NORTHWEST AREAS TO HIGHS IN THE MID-UPPER 80S VERSUS
LOWER 90S.

05/

&&

.PREV DISCUSSION... /ISSUED 331 AM CDT THU OCT 2 2014/
WATER VAPOR LOOP SHOWS A PRONOUNCED SHORTWAVE TROUGH OVER NEW MEXICO
RAPIDLY MOVING EASTWARD TOWARD THE REGION. FORCING FOR ASCENT AHEAD
OF THIS FEATURE IS ALREADY REACHING THE REGION...AS AIRCRAFT DATA
INDICATES LIFTING AND DYNAMIC COOLING OF THE MID LEVEL TEMPERATURE
PROFILE. WHERE ENOUGH MOISTURE EXISTS ALOFT...ACROSS THE NW ZONES
AND OKLAHOMA...THIS LIFT IS ALLOWING ELEVATED PARCELS TO REACH THEIR
LFC AND CONVECT. THIS SCATTERED ELEVATED CONVECTION WILL REMAIN
PRIMARILY NORTH OF THE REGION THIS MORNING...BUT THE NORTHWEST AND
NORTHERN ZONES WILL HAVE A CHANCE OF MORNING SHOWERS OR STORMS.

THE COLD FRONT IS NOW ENTERING THE TEXAS PANHANDLE AND IS FORECAST
TO REACH THE NW ZONES BY MIDDAY.  MODEL GUIDANCE IS AN HOUR OR TWO
FASTER WITH THE FRONT...BUT OVERALL THERE IS LITTLE CHANGE TO THE
FORECAST THINKING OF THE LAST FEW DAYS. AHEAD OF THE FRONT...SOUTH
TO SOUTHWEST WINDS OF 10 TO 20 MPH WILL ENSURE A WARM MORNING AND
ONCE THE LOW STRATUS SCATTERS OUT BY MIDDAY...SUNSHINE WILL BOOST
TEMPS INTO THE LOW TO MID 90S OVER THE REGION.  THESE HOT TEMPS AND
DEWPOINTS NEAR 70 OCCURRING IN CONJUNCTION WITH DYNAMIC COOLING
ALOFT WILL RESULT IN A MODERATELY UNSTABLE AIRMASS DEVELOPING THIS
AFTERNOON WITH CAPE REACHING 2000-2500 J/KG. WHILE A FAIRLY STRONG
INVERSION NEAR 850MB WILL CAP OFF CONVECTIVE POTENTIAL EARLY IN THE
DAY...THE COMBINATION OF DYNAMIC LIFT AHEAD OF THE SHORTWAVE
TROUGH...CONVERGENCE ALONG THE FRONT...AND AFTERNOON HEATING WILL
ALL WORK TO ERODE CONVECTIVE INHIBITION OVER THE AREA.

SURFACE BASED CONVECTION IS EXPECTED TO FORM ALONG THE FRONT OVER
THE NW ZONES AROUND 1 PM AS THE CAP BEGINS TO BREAK. CONVECTION WILL
CONTINUE TO DEVELOP SOUTHWARD ALONG THE FRONT THROUGH THE MID-LATE
AFTERNOON HOURS AS IT MARCHES SOUTHEAST INTO THE CENTRAL ZONES. WE
EXPECT FROPA AROUND 3 PM NEAR GAINESVILLE...5 PM NEAR DFW...AND 7PM
NEAR WACO.  WHEN THE FRONT CROSSES THE I-35 CORRIDOR A SQUALL LINE
WILL BEGIN TO TAKE SHAPE...WHICH MEANS THERE MAY STILL BE A FEW GAPS
IN THE LINE AT THIS TIME. A FULLY DEVELOPED AND MATURE SQUALL LINE
WILL EXIST AS THE FRONT MOVES EAST OF THE I-35 CORRIDOR EARLY THIS
EVENING...AND IT APPEARS THE THREAT FOR DAMAGING WINDS IS HIGHEST IN
THIS REGION. THE CAP WILL BE A LITTLE STRONGER OVER THE WESTERN AND
SOUTHWESTERN ZONES...AND ACTIVITY WILL LIKELY BE MORE ISOLATED
THERE. WHERE CONVECTION IS MORE ISOLATED...SUPER-CELLULAR STORM MODE
IS FAVORED...WHICH MEANS THERE IS AN ENHANCED LARGE HAIL THREAT IN
ADDITION TO A WIND THREAT. WHILE LOW LEVEL WIND PROFILES DO NOT
APPEAR FAVORABLE FOR LOW LEVEL ROTATION...SURFACE BASED SUPERCELLS
CAN STILL PRODUCE ISOLATED TORNADOES GIVEN THE RIGHT MESOSCALE
CONDITIONS...BUT THIS CANNOT BE FORECAST RELIABLY AT THIS TIME RANGE.

THE FRONT AND LINE OF STORMS WILL RAPIDLY CLEAR THE REGION FROM
NORTHWEST TO SOUTHEAST THIS EVENING. DRIER AND SLIGHTLY COOLER AIR
WILL MOVE INTO THE REGION OVERNIGHT...BUT NORTHERLY WINDS WILL NOT
REALLY INCREASE UNTIL FRIDAY WHEN A STRONGER HIGH PRESSURE SURGE
ARRIVES. HIGHS FRIDAY WILL BE COOLER AND GENERALLY TOP OUT NEAR 80
IN THE NORTH AND THE MID 80S SOUTH. THE SURFACE HIGH WILL SETTLE IN
RIGHT OVER THE CWA BY SUNRISE SATURDAY AND WINDS WILL GO CALM. WITH
DEWPOINTS BY THIS TIME IN THE 30S AND 40S...LOWS SATURDAY MORNING
SHOULD REACH THE 40S FOR A LARGE PORTION OF THE CWA...WITH LOW 50S
FOR THE DFW AREA AND THE SOUTHEAST CWA.  SATURDAY WILL BE SUNNY AND
PLEASANT WITH HIGHS TOPPING OUT NEAR 80...BUT WINDS WILL SWITCH TO
THE SOUTH BY SATURDAY EVENING.

INCREASING MOISTURE AND A MODERATION OF TEMPS BACK ABOVE NORMAL WILL
OCCUR SUNDAY INTO EARLY NEXT WEEK. THE 00Z ECMWF HAS AN OUTLIER
SOLUTION OF A STRONG SHORTWAVE ROTATING THROUGH IN NORTHWEST FLOW
ALOFT ON MONDAY WHICH BRINGS ANOTHER WEAK FRONT AND A CHANCE OF RAIN
TO THE AREA. THE GFS/CANADIAN/UKMET ARE MUCH WEAKER WITH THIS ENERGY
AND THEREFORE SHOW DRY WEATHER WITH HIGH TEMPS WARMING INTO THE 90S
WITH LOWS IN THE 60S AND 70S.  WILL KEEP FORECAST THE DRY BUT AS A
NOD TO THE ECMWF POTENTIAL WILL NUDGE HIGH TEMPS DOWNWARD INTO THE
MID TO UPPER 80S FOR NEXT WEEK INSTEAD OF THE CLIMATOLOGICALLY BOLD
FORECAST OF LOWER 90S.

TR.92

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  91  59  82  50  80 /  70  20   0   0   0
WACO, TX              94  58  84  49  81 /  60  40   5   0   0
PARIS, TX             90  57  78  45  76 /  80  60   0   0   0
DENTON, TX            90  54  81  43  80 /  70  10   0   0   0
MCKINNEY, TX          91  56  81  43  78 /  80  30   0   0   0
DALLAS, TX            92  60  82  51  80 /  80  30   0   0   0
TERRELL, TX           93  59  82  48  79 /  80  50   0   0   0
CORSICANA, TX         93  61  83  49  79 /  60  60   5   0   0
TEMPLE, TX            94  60  85  50  81 /  50  50   5   0   0
MINERAL WELLS, TX     90  54  82  44  81 /  40  10   0   0   0

&&

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

&&

 /

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1242 PM CDT THU OCT 2 2014

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-031100-
MONTAGUE-COOKE-GRAYSON-FANNIN-LAMAR-YOUNG-JACK-WISE-DENTON-COLLIN-
HUNT-DELTA-HOPKINS-STEPHENS-PALO PINTO-PARKER-TARRANT-DALLAS-
ROCKWALL-KAUFMAN-VAN ZANDT-RAINS-EASTLAND-ERATH-HOOD-SOMERVELL-
JOHNSON-ELLIS-HENDERSON-COMANCHE-MILLS-HAMILTON-BOSQUE-HILL-NAVARRO-
FREESTONE-ANDERSON-LAMPASAS-CORYELL-BELL-MCLENNAN-FALLS-LIMESTONE-
LEON-MILAM-ROBERTSON-
1242 PM CDT THU OCT 2 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.
THUNDERSTORMS WILL DEVELOP ALONG A COLD FRONT AS IT MOVES ACROSS
THE REGION THIS AFTERNOON AND EVENING. THE BEST CHANCES FOR
THUNDERSTORMS WILL BE ALONG AND EAST OF INTERSTATE 35/35W LATE
THIS AFTERNOON AND EVENING. THERE IS A SLIGHT RISK FOR SEVERE
STORMS ACROSS ALL OF NORTH AND CENTRAL TEXAS. LARGE HAIL AND
DAMAGING WINDS WILL BE THE MAIN THREATS BUT AN ISOLATED TORNADO
CANNOT BE RULED OUT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS LIKELY THIS AFTERNOON AND EVENING ACROSS
THE REGION.