Flash Flooding and Flooding in Texas, November 26 to 30, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
948 PM CST THU NOV 26 2015

.UPDATE...
THE RAIN EVENT IS WELL UNDERWAY WITH OVER 4 INCHES OF RAIN
ALREADY ACROSS PARTS OF WISE COUNTY. IT APPEARS AS IF THE SEVERE
WEATHER THREAT HAS DIMINISHED WITH LOSS OF SURFACE HEATING. WE
EXPECT PERIODS OF RAIN AND THUNDERSTORMS TO CONTINUE TROUGH THE
OVERNIGHT HOURS. IT DOES APPEAR THAT THE NORTHWEST ZONES WILL SEE
A BREAK IN THE ACTION UNTIL THE COLD FRONT ARRIVES IN A FEW HOURS.
AS OF 9 PM...THE FRONT WAS ALREADY SOUTH OF WICHITA FALLS AND
FAST APPROACHING THE NORTHWEST ZONES. THE FRONT WILL BRING
ADDITIONAL LIFT FOR RAIN AND ISOLATED STORMS.

NOT MUCH CHANGE NEEDED FOR THIS UPDATE OTHER THAN TO ADJUST FRONT
TIMING UP ABOUT AN HOUR AND ADJUST TEMPS/WINDS ACCORDINGLY.

AS A SIDE NOTE...DFW IS NOW IN SECOND PLACE FOR YEARLY RAINFALL.
AS OF 945 PM 1.84" OF RAIN HAS FALLEN TODAY WHICH BRINGS THE
YEARLY TOTAL TO 52.59 WHICH IS 0.95 INCHES AWAY FROM THE ALL TIME
YEARLY RAINFALL RECORD.

&&

.AVIATION...
/ISSUED 538 PM CST THU NOV 26 2015/

NORTH TEXAS AVIATION CONCERNS...DEVELOPING IFR CONDITIONS...
PERIODS OF HEAVY RAIN...EMBEDDED THUNDER AT TIMES AND A STRONG
COLD FRONT.

A DEEP UPPER LOW OVER THE INTER-MOUNTAIN WEST WILL MOVE LITTLE
DURING THIS FORECAST AND CONTINUE TO SPREAD FORCING FOR LIFT
ACROSS THE REGION. IN THE LOWER LEVELS...DEEP WARM AIR/MOISTURE
ADVECTION AND SIGNIFICANT ISENTROPIC ASCENT WILL RESULT IN PERIODS
OF LIGHT TO HEAVY RAINFALL OVER THE NEXT 24 HOURS AND A FLASH
FLOOD WATCH IS IN EFFECT FOR ALL METROPLEX TERMINALS. RAIN AMOUNTS
OF 3 TO 5 INCHES POSSIBLE BY 28/06 UTC. THUNDER WILL BE MOST
LIKELY ALONG AND BEHIND THE COLD FRONT FRIDAY MORNING FOR AT
LEAST 6 HOURS BUT MAY STILL OCCUR FRIDAY AFTERNOON AND EVENING.

EXPECTING CIGS TO BECOME IFR LATER EVENING AND LAST THROUGH ALL
OF FRIDAY. MVFR VISIBILITY WILL BOUNCE IN AND OUT OF IFR AS
MODERATE TO HEAVY RAIN EVENTS MOVE ACROSS THE REGION.

A STRONG COLD FRONT WILL BLAST THROUGH THE METROPLEX 12-13 UTC
FRIDAY AND AROUND 17Z AT KACT. THUS SOUTH WINDS WILL PREVAIL TONIGHT
NEAR/AROUND 16 KNOTS WITH SOME HIGHER GUSTS. WINDS WILL BECOME NORTH
AROUND 15 KNOTS BEHIND THE COLD FRONT AND CONTINUE THROUGH THE
AFTERNOON/EVENING HOURS. 75

&&

.PREV DISCUSSION... /ISSUED 318 PM CST THU NOV 26 2015/
ONLY MINOR ADJUSTMENTS TO PREVIOUS FORECASTS WERE NEEDED REGARDING
OUR SYSTEM AND PROLONGED RAIN EVENT...THAT WILL COME IN TWO OR
POSSIBLY THREE ROUNDS. THE FIRST LEAD SHORTWAVE ALOFT ARRIVED
SLIGHTLY SOONER THAN EXPECTED AND MANY AREAS ALONG AND WEST OF
I-35 HAVE ALREADY SEEN RAIN WITH ISOLATED THUNDERSTORMS TODAY
WHERE AN AREA OF ENHANCED ISENTROPIC ASCENT WAS OCCURRING. MOST
AMOUNTS HAVE BEEN AN INCH OR LESS...BUT WITH THE ATMOSPHERE PRIMED
AND AT MAX MOISTURE FOR THIS TIME OF THE YEAR...OCCASIONAL SHOWERS
OR THUNDERSTORMS THROUGH THIS EVENING WILL PRODUCE EFFICIENT
RAINFALL RATES. MEANWHILE...THE WELL-ADVERTISED ARCTIC COLD FRONT
WAS MARCHING THROUGH THE WESTERN HIGH PLAINS AND HAD MOVED INTO
THE TEXAS PANHANDLE AS OF EARLY AFTERNOON. A MARGINAL RISK FOR
SEVERE WEATHER WAS STILL NOTED BY SPC FOR AHEAD OF THE COLD FRONT
OVER OUR NORTHWEST COUNTIES...BUT CURRENT CLOUDS AND SHOWER
ACTIVITY HAVE HELD TEMPERATURES DOWN IN THAT AREA WITH MINIMAL TO
NO INSTABILITY TO WORK OFF OF DESPITE THE STRONG DEEP-LAYER SHEAR
OVER THE REGION. AS SUCH...WE EXPECT THE SEVERE WEATHER THREAT TO
BE VERY LOW WITH ONLY GUSTY WINDS POSSIBLE WITH ANY EMBEDDED...
STRONGER THUNDERSTORMS THROUGH SUNSET THIS EVENING.

THE MAIN POSITIVELY TILTED AND SLOW-MOVING LONGWAVE TROUGH OVER
THE GREAT BASIN WILL MOVE LITTLE THE NEXT 24 HOURS AND ACTUALLY
DIG OVER THE SOUTHWEST STATES AND CLOSE OFF THROUGH SATURDAY.
MEANWHILE...THE SHALLOW ARCTIC FRONT ARRIVES INTO OUR NORTHWEST
COUNTIES BY MIDNIGHT AND MOVE GRADUALLY THROUGH MUCH OF THE AREA
ON FRIDAY. THE BEST AGEOSTROPIC FORCING AND ISENTROPIC ASCENT
TONIGHT INTO EARLY FRIDAY WILL BE FOCUSED ACROSS THE NORTHWEST
COUNTIES IN VICINITY OF 130KT UPPER LEVEL JET MAXIMUM OVER THE
HIGH PLAINS AND ROCKIES. WE EXPECT THIS FIRST LEAD UPPER DISTURBANCE
TO EXIT NORTHEAST OF THE AREA LATER ON FRIDAY MORNING AND WE COULD
SEE RAIN ACTIVITY ACTUALLY WANE FRIDAY AFTERNOON INTO EARLY FRIDAY
EVENING WITH THE EXCEPTION OF SOME SCATTERED SHOWERS ACROSS THE
NORTHERN COUNTIES. THE FRONTAL SLOPE WILL BE VERY SHALLOW...SO WE
DO NOT EXPECT ADDITIONAL ASSISTANCE FROM THE FRONT WITH REGARD TO
FORCING. AS FOR TEMPERATURES WITH THE FRONT...WE HAVE ADVERTISED
MORNING HIGH TEMPERATURES WITH STRONG CAA EXPECTED BEHIND THE
FRONT. AS THE FRONT PROGRESSES SOUTH... TEMPERATURES WILL PLUMMET
INTO THE MID-UPPER 30S ACROSS THE NORTHWEST AND INTO THE 40S
ACROSS MUCH OF THE REMAINDER OF THE AREA LATER ON FRIDAY. THE
BLUSTERY NORTH WINDS WILL RESULT IN AFTERNOON WIND CHILLS FALLING
INTO THE UPPER 20S TO MID 30S WELL BEHIND THE COLD FRONT.

ANOTHER SHORTWAVE EJECTS OUT FRIDAY NIGHT INTO SATURDAY AND THIS
WILL BE ROUND TWO OF OUR PROLONGED RAINFALL EVENT. A BULK OF THE
MORE WIDESPREAD MODERATE TO HEAVIER RAINFALL WILL CONTINUE TO SET
UP FROM I-20 CORRIDOR TO THE RED RIVER VALLEY...AS THIS WILL BE
THE AREA ISENTROPIC ASCENT WILL BE THE MOST MAXIMIZED. IT WILL
CONTINUE TO REMAIN CHILLY FRIDAY NIGHT THROUGH SATURDAY NIGHT WITH
LOW DIURNAL SPREADS ON TEMPERATURES DUE TO THE COLD AIRMASS IN
PLACE AND CONTINUED PERIODS OF RAIN. LUCKILY...THE FREEZING LINE
LOOKS TO REMAIN OFF TO OUR WEST AND NORTHWEST AND WE DO NOT EXPECT
ANY FREEZING PRECIPITATION IN OUR AREA...ESPECIALLY WITH THE
STRONG WAA/LIFT OCCURRING OVER THE TOP OF THE SHALLOW COLD
AIRMASS.

THE FLASH FLOOD WATCH AREA WILL REMAIN INTACT FROM 6 PM THIS
EVENING THROUGH SUNRISE SUNDAY MORNING. THE HEAVIEST RAINFALL
TOTALS ARE STILL EXPECTED TO OCCUR ACROSS THE NORTH. THROUGH
SUNDAY MORNING...3 TO 7 INCHES OF RAIN MAY FALL ACROSS THE WATCH
AREA...WITH ISOLATED TOTALS BETWEEN 8-10 INCHES NOT OUT OF THE
QUESTION ACROSS THE IMMEDIATE RED RIVER VALLEY. LOCALIZED FLASH
FLOODING AND RIVER FLOODING ON THE UPPER REACHES OF THE BRAZOS...
TRINITY...AND SULPHUR BASINS STILL LOOKS LIKE A GOOD BET AS WE
MOVE INTO THE LATTER PART OF THE HOLIDAY WEEKEND. MINOR TO EVEN
POSSIBLY MODERATE FLOODING COULD OCCUR DEPENDING ON RUN OFF...WHICH
SHOULD BE MORE EFFICIENT AFTER A FEW FREEZES EARLIER IN THE WEEK.

BY SUNDAY...MODELS ARE IN GOOD AGREEMENT WITH A FOGGIER WOBBLE OF
THE UPPER LOW BACK TO THE NORTHEAST OVER THE CENTRAL AND NORTHERN
ROCKIES THROUGH SUNDAY NIGHT. THIS SHOULD BRING A MORE STRONG AND
DRY WEST-NORTHWEST FLOW ALOFT REGIME TO THE AREA AND SHUNT THE
BETTER MOISTURE AND RAIN CHANCES OFF TO THE EAST-NORTHEAST. HIGH
RAIN CHANCES WILL LINGER ON SUNDAY FOR THOSE TRAVELING HOME...BUT
NEITHER SEVERE WEATHER OR WINTER WEATHER ISSUES ARE EXPECTED. JUST
MAINLY A COOL RAIN. A DRY AND COOL PERIOD LOOKS ON TAP FOR THE
EARLY HALF OF NEXT WEEK AS ANOTHER COLD FRONT SURGES IN TUESDAY TO
REINFORCE THE PREVIOUS COLD AIRMASS AND KEEP THE GULF OF MEXICO
SHUT DOWN. MEDIUM RANGE MODELS REALLY DIVERGE ON SOLUTIONS THE
LATTER HALF OF THE WEEK WITH AN OPEN AND PROGRESSIVE SHORTWAVE
TROUGH. REGARDLESS OF TIMING...IT APPEARS MOST MOISTURE WILL
REMAIN TRAPPED FROM SOUTH-CENTRAL TEXAS TO THE LOWER RIO GRANDE
VALLEY AND HAVE LEFT THE FORECAST SEASONABLE AND DRY.    05/

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  68  68  38  39  38 / 100 100 100 100 100
WACO, TX              69  69  40  41  39 /  70  80  80  80  80
PARIS, TX             67  67  40  43  41 /  90  90 100 100 100
DENTON, TX            55  55  37  38  37 / 100 100 100 100  90
MCKINNEY, TX          67  67  38  40  38 / 100 100 100 100 100
DALLAS, TX            68  68  39  40  38 /  90  90 100  90 100
TERRELL, TX           67  67  40  42  39 /  70  90  90  90 100
CORSICANA, TX         68  68  42  44  40 /  60  70  80  80  90
TEMPLE, TX            69  69  40  42  39 /  70  70  70  70  80
MINERAL WELLS, TX     52  52  34  35  35 / 100 100 100 100  90

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE SATURDAY NIGHT FOR TXZ091>095-
100>107-115>123-129>135-141>146.

&&

75/79

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FORT WORTH TX
307 PM CST THU NOV 26 2015

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-271230-
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-
307 PM CST THU NOV 26 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL TEXAS.

.DAY ONE...TONIGHT.

WIDESPREAD RAIN AND A FEW THUNDERSTORMS WILL BE EXPECTED TONIGHT.
SOME OF THE STORMS MAY PRODUCE HEAVY RAINFALL THAT MAY CAUSE FLASH
FLOODING. A FLASH FLOOD WATCH IS IN EFFECT BEGINNING THIS EVENING
ALONG AND NORTH OF A LINE FROM GOLDTHWAITE...TO HILLSBORO...TO
ATHENS. OCCASIONAL LIGHTNING STRIKES ARE EXPECTED WITH ANY
THUNDERSTORMS THAT DEVELOPS THIS EVENING AS WELL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THE THREAT FOR FLASH FLOODING INCREASES ON FRIDAY AND SATURDAY AS
PERIODS OF MODERATE TO HEAVY RAIN CONTINUE. SOME FLOOD IMPACTS MAY
CONTINUE INTO SUNDAY WHEN THE RAIN FINALLY ENDS. RIVER FLOODING
MAY ALSO OCCUR DURING THIS TIME PERIOD. THE MOST LIKELY AREAS
EXPECTED TO EXPERIENCE FLOODING ARE ALONG AND NORTH OF A LINE FROM
GOLDTHWAITE...TO HILLSBORO...TO ATHENS WHERE A FLASH FLOOD WATCH
IS IN EFFECT THROUGH SUNRISE SUNDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
637 PM CST THU NOV 26 2015

TXZ117-131-270100-
PARKER-HOOD-
637 PM CST THU NOV 26 2015

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN HOOD AND SOUTH CENTRAL
PARKER COUNTIES...

AT 637 PM CST...A STRONG THUNDERSTORM WAS OVER LIPAN...OR 13 MILES
NORTHWEST OF GRANBURY...MOVING NORTHEAST AT 55 MPH.

WINDS IN EXCESS OF 30 MPH ARE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
WEATHERFORD...GRANBURY...HUDSON OAKS...ANNETTA...LIPAN...OAK TRAIL
SHORES...TOLAR...ANNETTA SOUTH AND ANNETTA NORTH.

THIS INCLUDES INTERSTATE 20 BETWEEN MILE MARKERS 406 AND 413.

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 3281 9770 3249 9762 3232 9798 3235 9800
      3256 9805
TIME...MOT...LOC 0037Z 240DEG 48KT 3252 9800

75