Flash Flood Warning 170, NWS Fort Worth, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
656 AM CDT FRI OCT 23 2015

.AVIATION...

FOR THE 12Z TAFS...COMPLEX SCENARIO INVOLVING THE TIMING OF THE
ONSET OF HEAVY PRECIPITATION ACROSS THE REGION IS THE PRIMARY
FORECAST CONCERN.

EARLY THIS MORNING...RAIN SHOWER AND THUNDERSTORM ACTIVITY HAS
BECOME ISOLATED IN NATURE IN THE IMMEDIATE DFW AREA. WENT AHEAD
WITH VCSH IN ALL OF THE DFW AREA TAFS TO ACCOUNT FOR CURRENT RADAR
TRENDS. OF GREATER IMMEDIATE CONCERN...IFR CEILINGS ARE IN PLACE
OVER KFTW AND KAFW...SEEMINGLY ASSOCIATED WITH A RETREATING
FRONTAL BOUNDARY OR COLD POOL FROM YESTERDAY'S THUNDERSTORM
ACTIVITY. WITH SOUTHERLY WINDS OBSERVED JUST SOUTH OF THESE
AIRPORTS...ANTICIPATE THAT THE IFR CEILINGS WILL BE SHORT LIVED...
SO ONLY HAVE THEM TEMPOED IN THROUGH 13Z. WILL HAVE TO WATCH THIS
CLOSELY THIS MORNING AND AMEND IF IT LOOKS LIKE CIGS WILL NOT
IMPROVE AS QUICKLY AS EXPECTED.

REMAINDER OF TODAY...MOST MODEL GUIDANCE INDICATES THAT RAIN
SHOWER AND THUNDERSTORM ACTIVITY WILL MOVE BACK TOWARDS THE DFW
AREA AFTER NOON. EVERY MODEL OFFERS A SLIGHTLY DIFFERENT
SOLUTION...SO SIMPLY WENT WITH A GENERIC VCTS IN THE TAFS AT THIS
TIME. AFTER THE FIRST 6 HOURS OF THE TAFS...THE FORECAST IS
EXPECTED TO BE HIGHLY DEPENDENT UPON SHORT TERM FORECASTING AND
THE RESULTANT AMENDMENTS.

VERY STRONG LIFT IS EXPECTED OVER THE REGION STARTING THIS
EVENING AND LASTING THROUGH THE OVERNIGHT HOURS. WIDESPREAD
CONVECTION IS EXPECTED OVER THE REGION AFTER MIDNIGHT...CONTINUING
THROUGH SATURDAY MORNING. WE MAY NOT SEE AN APPRECIABLE BREAK IN
THE CONVECTION/PRECIPITATION UNTIL A COLD FRONT PUSHES ACROSS THE
DFW AREA AROUND NOON TOMORROW. CONVECTION WILL LIKELY NOT WEAKEN
IMMEDIATELY BEHIND THE FRONT...BUT 3-4 HOURS BEHIND THE COLD FRONT
WE MAY SEE AN END TO THE WIDESPREAD PRECIPITATION ACROSS THE
REGION.

CAVANAUGH

&&

.PREV DISCUSSION... /ISSUED 441 AM CDT FRI OCT 23 2015/

.....QUICK OVERVIEW...PRECIPITATION EVENT.....

FLASH FLOOD WATCH...  NOW INCLUDES ALL OF NORTH TEXAS THROUGH 7AM
SUNDAY.

HEAVIEST RAINFALL AREAS...  WIDESPREAD TODAY ACROSS ALL OF THE
AREA WITH HEAVIEST LIKELY JUST SOUTHEAST OF THE METROPLEX.
HEAVIEST RAIN SHIFTS BACK TO THE NORTHWEST LATE TONIGHT AS COLD
FRONT APPROACHES. ON SATURDAY...HEAVIEST RAINFALL WILL BE ACROSS
THE SOUTHEAST COUNTIES AS WELL DEFINED SURFACE LOW DEVELOPS ALONG
THE TEXAS COAST.

RAINFALL AMOUNTS...  ADDITIONAL 3 TO 6 INCHES OF RAIN THROUGH
SUNDAY ACROSS MOST OF NORTH TEXAS. ISOLATED 8 TO 10 INCH AMOUNTS.

SEVERE WEATHER THREAT...  LOW THROUGH SUNDAY. WIND SHEAR REMAINS
STRONG SO AN ISOLATED STRONG TO SEVERE STORM POSSIBLE.

FLASH FLOODING THREAT...  HIGH. WILL INCREASE THROUGH SATURDAY AS
MORE RAIN FALLS ON WET GROUNDS. URBAN AREAS WILL BE MOST
SUSCEPTIBLE AS RAINS CONTINUE.

RIVER FLOODING THREAT...  MODERATE. RIVERS ARE NOW STARTING TO
RESPOND UPWARD WITH CONTINUED RAIN. SHOULD SEE MORE RUNOFF MAKING
IT INTO STREAMS AND CREEKS THROUGH TONIGHT.

.....DISCUSSION.....

MAIN CONCERNS OVER THE NEXT 24 HOURS WILL BE THE LOCATION OF
HEAVIEST RAINFALL ACROSS NORTH TEXAS. WATER VAPOR IMAGERY SHOWS A
DEPARTING TROUGH OVER THE NORTHERN PLAINS WITH ANOTHER TROUGH
APPROACHING THE AREA FROM THE WEST. TO THE SOUTH...MAJOR HURRICANE
PATRICIA NOW HAS SUSTAINED WINDS OF 200 MPH AND WILL MAKE LANDFALL
LATER THIS EVENING IN SOUTHWEST MEXICO. A HURRICANE THIS STRONG
HAS A WELL DEFINED MATURE ANTICYCLONE ABOVE THE CENTER OF LOW
PRESSURE WHICH EFFICIENTLY EVACUATES AIR OUT OF THE TOP OF THE
HURRICANE. THIS IS EVIDENT IN THE WATER VAPOR IMAGERY AS CLOCKWISE
ROTATING BANDS WHICH ALREADY EXTENDS INTO DEEP SOUTH TEXAS. THIS
FEATURE WILL BECOME IMPORTANT LATER TONIGHT TO HELP ENHANCE SHOWER
AND THUNDERSTORM DEVELOPMENT ACROSS CENTRAL AND NORTH TEXAS.

THOUGHTS FOR TODAY...ONGOING SHOWERS AND STORMS HAVE SHOWED SIGNS
OF WEAKENING IN INTENSITY OVER THE LAST HOUR AND THE WELL DEFINED
OUTFLOW BOUNDARY THAT WAS ASSOCIATED WITH THIS CONVECTION IS NOW
RETREATING TO THE NORTHWEST. WINDS IN THE METROPLEX HAVE NOW
BECOME SOUTHEAST AND TEMPERATURES HAVE WARMED A FEW DEGREES. THIS
SUGGESTS THAT THE BOUNDARY ITSELF MAY NOT BE AS IMPORTANT IN
FOCUSING NEW CONVECTION THROUGH THE MORNING HOURS.
INSTEAD...NUMEROUS SHOWERS AND STORMS HAVE DEVELOPED ON THE NOSE
OF A 35KT LLJ ACROSS CENTRAL AND SOUTHEAST TEXAS AND ARE SPREADING
NORTH-NORTHEAST. ADDITIONAL SHOWERS AND STORMS HAVE DEVELOPED TO
THE WEST OF THE METROPLEX IN AN AREA OF MODERATE WARM ADVECTION
AND WILL LIKELY CONTINUE THROUGH MORNING. ITS TOUGH TO SAY EXACTLY
WHERE THE HEAVIEST RAIN WILL BE TODAY...BUT MOST OF NORTH TEXAS
SHOULD SEE ON AND OFF SHOWERS AND STORMS. THE ONLY EXCEPTION MIGHT
BE THE FAR NORTHWEST COUNTIES WHERE CONVECTION MAY BE MORE
SCATTERED. HIGHEST QPF AMOUNTS ARE LIKELY TO BE ACROSS CENTRAL AND
SOUTHEAST PARTS OF THE CWA...WHERE STRONG LOW LEVEL WARM ADVECTION
WILL BE PERSISTENT THROUGHOUT THE DAY.

BY TONIGHT...THE LARGE UPPER TROUGH TO THE WEST WILL MOVE INTO
WEST TEXAS AND LARGE SCALE FORCING FOR ASCENT WILL INCREASE ACROSS
THE REGION. IN ADDITION...THE REMNANTS OF HURRICANE PATRICIA WILL
BE MOVING INTO CENTRAL MEXICO BUT THE NORTHERN FRINGES OF THE
UPPER LEVEL ANTICYCLONE WILL BE MOVING INTO NORTH TEXAS. THIS WILL
HELP TO GREATLY INCREASE UPPER LEVEL DIVERGENCE ACROSS THE REGION
ALONG WITH PROVIDING ADDITIONAL MID AND UPPER LEVEL MOISTURE. A
COLD FRONT WILL ALSO BE MOVING INTO THE AREA AND SHOULD PROVIDE A
GOOD FOCUS FOR NUMEROUS SHOWERS AND STORMS TO DEVELOP. THIS WILL
LIKELY TAKE PLACE SOMEWHERE ACROSS OUR NORTHWEST AND CENTRAL
COUNTIES FROM GOLDTHWAITE TO FORT WORTH TO BONHAM. THIS AREA COULD
SEE AN ADDITIONAL 3 INCHES OF RAIN OR MORE DURING THE OVERNIGHT
HOURS. AS THE UPPER TROUGH CONTINUES TO MOVE EAST...A WELL DEFINED
SURFACE LOW WILL DEVELOP ALONG THE SOUTH TEXAS COAST DURING THE
DAY SATURDAY. THIS SURFACE LOW WILL DEEPEN DURING THE DAY AND THE
FOCUS FOR HEAVY RAINFALL WILL LIKELY SHIFT SOUTH TOWARD THE LOW
PRESSURE CENTER. THIS MEANS THAT WE SHOULD SEE A SOUTHWARD MOVING
THREAT FOR HEAVY RAINFALL ON SATURDAY. THE HEAVIEST RAINFALL IN
OUR SOUTHEAST COUNTIES IS LIKELY TO OCCUR LATE IN THE DAY SATURDAY
AND SATURDAY NIGHT. THIS WHOLE SYSTEM WILL MOVE EAST OF THE AREA
INTO EARLY NEXT WEEK BUT WE WILL HANG ON TO SOME POPS ACROSS THE
EASTERN HALF OF THE CWA THROUGH EARLY MONDAY.

ANOTHER SHORTWAVE APPROACHES THE AREA LATE TUESDAY NIGHT INTO
WEDNESDAY AND THERE MAY BE ENOUGH MOISTURE TO GET SOME SCATTERED
SHOWERS ACROSS THE NORTHEAST COUNTIES DURING THIS TIME.
OTHERWISE...NO MAJOR CHANGES TO THE EXTENDED FORECAST.

DUNN

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  78  68  73  60  71 / 100 100 100  60  30
WACO, TX              79  68  75  61  71 / 100  90 100  70  40
PARIS, TX             76  65  73  60  71 / 100  90  80  60  60
DENTON, TX            77  65  71  58  69 /  90 100  90  50  20
MCKINNEY, TX          77  66  72  59  70 / 100 100  90  60  30
DALLAS, TX            78  68  73  61  71 / 100 100 100  70  30
TERRELL, TX           77  67  74  61  70 / 100 100 100  70  50
CORSICANA, TX         79  68  76  63  71 /  90  90 100  80  50
TEMPLE, TX            80  67  74  61  71 /  90  90 100  80  40
MINERAL WELLS, TX     77  64  71  57  70 /  80 100  80  40  20

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY MORNING FOR TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FORT WORTH TX
454 AM CDT FRI OCT 23 2015

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-241000-
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-
454 AM CDT FRI OCT 23 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT.

THROUGH THE DAYLIGHT HOURS TODAY...NUMEROUS SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS MUCH OF NORTH TEXAS. WHILE
LOCALLY HEAVY RAINFALL COULD OCCUR ANYWHERE ACROSS NORTH CENTRAL
TEXAS...THE HEAVIEST RAIN IS EXPECTED TO REMAIN ALONG AND
SOUTHEAST OF A LINE FROM GOLDTHWAITE TO DALLAS TO PARIS. THE
PRIMARY CONCERN WILL BE LOCALIZED FLASH FLOODING AND CLOUD TO
GROUND LIGHTNING STRIKES.

AFTER SUNSET...THE CORE OF HEAVIEST RAINFALL IS EXPECTED TO
INTENSIFY AND REFOCUS A BIT FARTHER NORTHWEST. THE HEAVIEST
RAINFALL IS EXPECTED TO OCCUR NEAR A COMANCHE TO FORT WORTH TO
COMMERCE LINE. FLASH FLOODING IS EXPECTED TO BE MORE OF A
WIDESPREAD THREAT FROM THIS EVENING THROUGH THE OVERNIGHT HOURS.
CLOUD TO GROUND LIGHTNING WILL CONTINUE TO BE A HAZARD.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NUMEROUS SHOWERS AND STORMS ARE EXPECTED ACROSS ALL OF NORTH TEXAS
FROM SATURDAY THROUGH SUNDAY MORNING. THE AXIS OF HEAVIEST
RAINFALL IS EXPECTED TO SHIFT SOUTHEAST DURING THE DAY ON
SATURDAY...WITH THE HEAVIEST RAIN FALLING SOUTH OF INTERSTATE 20
AND EAST OF INTERSTATE 35 ON SATURDAY. FLASH FLOODING WILL BE THE
MAIN THREAT DURING THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

CAVANAUGH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FORT WORTH TX
827 AM CDT FRI OCT 23 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     HEAVY RAIN       IREDELL                 31.98N  97.87W
10/23/2015  M4.85 INCH       BOSQUE             TX   TRAINED SPOTTER

            24 HOUR TOTAL ENDING AT 630 AM; IREDELL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FORT WORTH TX
841 AM CDT FRI OCT 23 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0826 AM     HEAVY RAIN       HEATH                   32.83N  96.45W
10/23/2015  M4.17 INCH       ROCKWALL           TX   PUBLIC

            10 HOURS ENDING AT 826 AM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FORT WORTH TX
846 AM CDT FRI OCT 23 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     HEAVY RAIN       ARLINGTON               32.73N  97.12W
10/23/2015  M3.31 INCH       TARRANT            TX   CO-OP OBSERVER

            RETIRED NWS EMPLOYEE REPORT IN SOUTH ARLINGTON 24
            HOUR TOTAL THROUGH 7 AM.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
1042 AM CDT FRI OCT 23 2015

TXZ118-119-231630-
DALLAS TX-TARRANT TX-
1042 AM CDT FRI OCT 23 2015

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN DALLAS AND SOUTHEASTERN
TARRANT COUNTIES UNTIL 1130 AM CDT...

AT 1041 AM CDT...DOPPLER RADAR WAS TRACKING A LINE OF STRONG
THUNDERSTORMS NEAR FOREST HILL OR SOUTHEAST FORT WORTH...MOVING EAST
AT 50 MPH.

WIND GUSTS UP TO...OR IN EXCESS OF 50 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
DALLAS...FORT WORTH...ARLINGTON...GRAND PRAIRIE...MESQUITE...
MANSFIELD...DESOTO...CEDAR HILL...DUNCANVILLE...BURLESON...
LANCASTER...BALCH SPRINGS...SEAGOVILLE...CROWLEY...FOREST HILL...
GLENN HEIGHTS...KENNEDALE...EVERMAN...HUTCHINS AND COCKRELL HILL.

THIS INCLUDES THE FOLLOWING INTERSTATES...
 INTERSTATE 35W BETWEEN MILE MARKERS 39 AND 51.
 INTERSTATE 35E BETWEEN MILE MARKERS 412 AND 427.
 INTERSTATE 20 BETWEEN MILE MARKERS 435 AND 485.
 INTERSTATE 820 BETWEEN MILE MARKERS 29 AND 35.
 INTERSTATE 45 BETWEEN MILE MARKERS 267 AND 284.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

VERY HEAVY TO TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS LINE
OF STORMS...AND MAY LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR
VEHICLE THROUGH FLOODED ROADWAYS.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 3255 9693 3257 9736 3275 9736 3279 9652
      3255 9652
TIME...MOT...LOC 1541Z 270DEG 45KT 3266 9727

05/