466
FXUS64 KSHV 181128
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
628 AM CDT WED SEP 18 2019
AVIATION
SHWRS/TSTMS TO CONTINUE TO INCREASE FROM THE SW TODAY, BRINGING AT
LEAST OCNL MVFR/IFR CONDITIONS TO E TX TERMINALS, AS THE REMNANTS
OF TROPICAL CYCLONE IMELDA MOVE NWD ACROSS E TX. CONVECTION MAY
DIMINISH IN COVERAGE SOMEWHAT AFTER SUNSET TONIGHT, BUT WILL
LIKELY CONTINUE AT KLFK NEAR THE CENTER OF CIRCULATION. WED
NIGHT/EARLY THU MORNING WILL BRING INCREASING COVERAGE OF
CONVECTION, WITH SHRA PREVAILING AT KTYR/KGGG AS WELL AFTER 00Z.
/12/
PREV DISCUSSION
/ISSUED 450 AM CDT WED SEP 18 2019/
SHORT TERM.../TODAY THROUGH THURSDAY NIGHT/
RAPIDLY EVOLVING WEATHER SCENARIO UNDERWAY THIS PD, AS THE
REMNANTS OF TS IMELDA CHURN ALONG THE SE TX COAST. MODELS
CONTINUING THE TREND TOWARDS HIGHER QPF AS THE CIRCULATION MOVES
NWD OVER E TX THE NEXT FEW DAYS. IN FACT, BOTH THE NAM AND THE
EURO HAVE OVER FIVE INCHES OF TOTAL PRECIP ACCUM OVER DEEP E TX,
THE GFS OVER FOUR INCHES, BY LATE THIS EVENING. NOT NECESSARILY
SAYING THAT WE SHOULD BUY THE DETERMINISTIC OUTPUT FROM RAW MODEL
DATA, BUT AGREEMENT IN RELATIVE PLACEMENT AND AMOUNTS BETWEEN
THREE MODELS SHOULD GIVE SOME PAUSE. COUPLE THAT WITH THE EURO
BEGINNING THE TREND TOWARDS THESE HEAVIER TOTALS YESTERDAY, AND
THERE SEEMS TO BE SOME PRETTY SOLID POINTERS TOWARDS A HEAVY
RAINFALL EVENT. IN COORDINATION WITH THE HOUSTON AND LAKE CHARLES
NWS OFFICES, HAVE DECIDED TO GO AHEAD AND ISSUE A FLASH FLOOD
WATCH FOR PORTIONS OF DEEP E TX BEGINNING AT 7 PM THIS EVENING AND
CONTINUING THROUGH 7 PM THURSDAY. THIS MAY NEED TO BE EXTENDED IN
BOTH TIME AND AREA, BUT WILL LEAVE THAT TO LATER SHIFTS WITH
ADDITIONAL MODEL RUNS TO CONSIDER.
WITH THE LIKELIHOOD OF WIDESPREAD RAINFALL TODAY AND THURSDAY,
EXPECT THAT DAYTIME MAX TEMPS WILL TAKE A BIG HIT, ESPECIALLY
ACROSS DEEP E TX TODAY AND EXTENDING FURTHER N AND E FOR THURSDAY.
WITH CLOUD COVER BCMG WIDESPREAD AS WELL, HAVE TRENDED OVERNIGHT
MINS JUST A BIT ABOVE THE NATIONAL BLEND. /12/
LONG TERM.../FRIDAY THROUGH WEDNESDAY/
BY FRIDAY, THE REMNANTS OF TROPICAL DEPRESSION IMELDA WILL CONTINUE
TO DETERIORATE WHILE DRIFTING NORTH THROUGH EAST TX. DESPITE THE
DETERIORATION OF THE SYSTEM'S ORGANIZATION, GOOD MOISTURE ADVECTION
ALONG WITH HIGH PRECIPITABLE WATER WILL POSSIBLY YIELD LOCALLY HEAVY
RAINFALL DURING THIS TIME SPAN ACROSS EAST TEXAS, NORTHWEST
LOUISIANA, EXTREME SOUTHEAST OKLAHOMA AND ADJACENT SOUTHWEST
ARKANSAS. THERE COULD BE ADDITIONAL FLOODING CONCERNS ACROSS THESE
AREAS AS MODELS INDICATE ADDITIONAL RAINFALL AMOUNTS OVER 5 INCHES
IN SOME PLACES. HOPEFULLY MOST AREAS WILL ONLY EXPERIENCE BENEFICIAL
RAINFALL TO EASE DROUGHT CONDITIONS OVER THE REGION.
THERE HAS BEEN SOME FLUCTUATION OVER THE PAST SEVERAL DAYS WITH THE
TRACK ON THIS SYSTEM, BUT THE LATEST MODEL CONSENSUS MOVES THIS
SYSTEM OUT OF EAST TEXAS LATE FRIDAY AND THROUGH THE OZARKS ON
SATURDAY BEFORE BECOMING ABSORB IN A LONGWAVE TROUGH DIGGING THROUGH
THE PLAINS TOWARDS OUR REGION LATE SATURDAY EVENING. ONLY A SLIGHT
CHANCE OF AFTERNOON DIURNAL CONVECTION IS EXPECTED ON SATURDAY AND
THROUGH THE WEEKEND AS AN UPPER LEVEL RIDGE BUILDS BACK INTO THE
SOUTHEAST CONUS. THE RIDGE WILL STALL THE LONGWAVE TROUGH AND
ASSOCIATED COLD FRONT JUST TO THE NORTHWEST OF OUR CWA. LONG RANGE
MODELS ARE IN GOOD AGREEMENT OF THE RIDGE HOLDING FIRMLY IN PLACE
THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL LIKELY RESULT IN HOT AND
DRY CONDITIONS RETURNING TO THE REGION BY EARLY NEXT WEEK.
HIGH TEMPERATURES DURING THE EARLY PORTIONS OF THE EXTENDED WILL
FALL BELOW NORMAL WITH RAIN AND CLOUD COVER OVER THE REGION.
AFTERNOON HIGHS WILL STRUGGLE TO REACH THE MID TO UPPER 80S ON
FRIDAY AND SATURDAY. HOWEVER, AFTERNOON TEMPERATURES WILL REBOUND
BACK INTO THE 90S AS THE RIDGE EXPANDS INTO THE REGION DURING THE
REMAINDER OF THE EXTENDED PERIOD. /20/
PRELIMINARY POINT TEMPS/POPS
SHV 92 74 84 72 / 30 40 70 50
MLU 97 74 93 73 / 20 10 50 30
DEQ 96 71 90 71 / 20 10 40 70
TXK 94 73 87 71 / 20 20 50 70
ELD 97 71 91 71 / 20 10 40 40
TYR 88 73 81 71 / 50 60 70 70
GGG 89 72 83 71 / 50 60 70 70
LFK 82 73 79 72 / 70 80 80 50
SHV WATCHES/WARNINGS/ADVISORIES
AR...NONE.
LA...NONE.
OK...NONE.
TX...FLASH FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR
TXZ152-153-165>167.
12/20
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