713
FXUS64 KLCH 230303
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1003 PM CDT MON JUL 22 2019
UPDATE
COLD FRONT CURRENTLY EXTENDS ACRS NRN LA. CONVECTION AHEAD OF THE
BOUNDARY HAS DIMINISHED SIGNIFICANTLY, ALTHOUGH A FEW ISOLATED
SHOWERS OR STORMS CONTINUE TO QUICKLY DEVELOP AND DISSIPATE AS THE
OUTFLOW FM EARLIER STORMS PUSHES SOUTHWARD. STILL EXPECT SOME SCTD
CONVECTION TO DEVELOP THROUGH THE OVERNIGHT HOURS AS THE FRONT
MOVES THROUGH THE AREA ALTHOUGH GUIDANCE SUGGESTS THE BEST
DEVELOPMENT WILL BE OVER THE COASTAL WATERS TOWARD DAYBREAK.
CONDITIONS WILL AGAIN BE WARM AND MUGGY OVERNIGHT AS THE FRONT
SLOWLY CROSSES THE AREA, WITH THE DRIER AIR EXPECTED TO ARRIVE
DURING THE DAY TUESDAY. EXPECT OVERNIGHT LOWS IN THE LOWER TO
MIDDLE 70S, SIMILAR TO THIS MORNING.
THE MAIN UPDATE THIS EVENING WAS TO POPS TO REFLECT THE LATEST
RADAR TRENDS AND SHORT TERM GUIDANCE. MINOR CHANGES WERE MADE TO
THE TEMPS, DEWPOINTS AND WINDS TO BRING IN LINE WITH RECENT OBS,
BUT OTHERWISE REMAIN ON TRACK. UPDATED TEXT PRODUCTS HAVE BEEN
SENT.
24
PREV DISCUSSION
/ISSUED 655 PM CDT MON JUL 22 2019/
DISCUSSION...
00Z TAF ISSUANCE.
AVIATION...
COOL FRONT MOVING THROUGH THE ARKLATEX THIS EVENING, WITH
SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF IT
APPROACHING INLAND SE TX/C LA. FOR THIS, WILL CONTINUE VCTS &
TEMPO FOR TSRA/MVFR VISIBILITY AND CEILINGS FOR AEX THROUGH 04Z.
AFTER 04Z FOR AEX AND REMAINDER OF TERMINALS, LEFT VCSH. NORTHWEST
WINDSHIFT SHOULD BE MOVING THROUGH AROUND 09Z FOR AEX, 12Z FOR
BPT, 13Z FOR LCH, AND 14-15Z FOR LFT/ARA WITH STRONGER WINDS
EXPECTED DURING THE AFTERNOON AROUND 10-12 KTS WITH GUSTS TO 20
KTS. WITH LINGERING INSTABILITY OVER SC LA, PLACED PROB30 GROUP
FOR TSRA/MVFR VISIBILITY AND CEILINGS AT LFT/ARA 15-21Z.
DML
PREV DISCUSSION... /ISSUED 430 PM CDT MON JUL 22 2019/
DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE AREA
THIS AFTERNOON, FUELED LARGELY BY DIURNAL INSTABILITY AND A
LINGERING WEAK TROF AXIS OVER THE REGION. THIS ACTIVITY WILL
CONTINUE FOR ANOTHER FEW HOURS, DISSIPATING NEAR OR AFTER SUNSET.
ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
AND/OR SPREAD IN FROM THE NORTH MID TO LATE EVENING WITH THE
APPROACH OF THE MUCH ADVERTISED FRONTAL BOUNDARY, CURRENTLY
EVIDENT IN OBSERVATIONAL DATA JUST ENTERING NW LA.
FRONT IS PROGGED TO CONTINUE SOUTH THROUGH THE AREA DURING THE
OVERNIGHT HOURS THROUGH TUE MORNING, WITH THE BULK OF THE RAINFALL
OVER THE AREA OCCURRING DURING THIS TIME FRAME. WHILE CONVECTIVE
CELLS WILL BE CAPABLE OF INTENSE RAIN RATES DUE TO THE HIGH
ATMOSPHERIC MSTR CONTENT, A QUICK SOUTHWARD MOVEMENT WILL
GENERALLY MITIGATE FLOODING CONCERNS. THE BOUNDARY MAY SLOW UP A
BIT ONCE IT NEARS THE COAST AS WEAK FRONTAL WAVE DEVELOPS. THE
RESULTANT SHARPENING OF THE FRONT MAY FOCUS STRONGER CONVECTION
OVER THE LOWER ATCHAFALAYA BASIN FOR A FEW HOURS TUE AFTERNOON,
WHICH WOULD YIELD LOCALLY HIGHER RAIN TOTALS AND AT LEAST A
LOCAL/URBAN FLOOD RISK. THE BOUNDARY IS NONETHELESS EXPECTED TO
CONTINUE ON TO THE SOUTH TUE NIGHT, PUSHING OUT OF THE MARINES
ZONES BY EARLY WED MORNING.
DEEP NORTHERLY FLOW IN THE WAKE OF THE FRONT WILL USHER DRIER AND
UNSEASONABLY COOLER AIR INTO THE REGION, WITH LOWS TUE NIGHT
THROUGH THU NIGHT IN THE MID/UPPER 60S, WITH LOWER 60S POSSIBLE
WED NIGHT ACROSS INTERIOR SE TX INTO CENTRAL LA. HIGHS WILL TOP
OUT IN THE MID TO UPPER 80S.
THE FRONT IS EXPECTED TO RETREAT BACK TO THE NORTH ON SAT, WITH
WARM AND HUMID AIR ALONG WITH DAILY RAIN CHANCES RETURNING SUN AND
MON.
AS A BRIEF ASIDE, RECENTLY DESIGNATED TD 3 OVER THE NW BAHAMAS IS
FORECAST TO BE ABSORBED INTO THE DIGGING ERN CONUS TROF, AND WILL
HAVE ZERO IMPACT ON OUR LOCAL WEATHER.
13
MARINE...
A LIGHT SOUTHWEST TO WESTERLY FLOW WILL PREVAIL OVER THE COASTAL
WATERS TONIGHT AS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DEVELOP DURING THE OVERNIGHT HOURS WITH THE APPROACH OF AN
UNSEASONABLE JULY COLD FRONT. THE FRONT WILL PROGRESS THROUGH THE
COASTAL WATERS DURING THE DAY TUE, ACCOMPANIED BY SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. THE FRONT WILL USHER IN A
PERIOD OF MODEST OFFSHORE FLOW TUE AFTERNOON THROUGH WED. SCEC
HEADLINES OR A SCA MAY BE NEEDED TUE NIGHT INTO WED MORNING. WINDS
WILL DECREASE AND BECOME SOMEWHAT VARIABLE FROM THE EAST THU
NIGHT INTO FRI AS THE BOUNDARY MEANDERS OVER THE GULF WATERS,
TURNING ONSHORE AGAIN FRI NIGHT AS THE FRONT RETREATS BACK TO THE
NORTH.
13
PRELIMINARY POINT TEMPS/POPS
AEX 73 83 64 86 / 40 40 0 0
LCH 75 84 69 87 / 50 50 10 0
LFT 74 83 69 86 / 50 60 20 10
BPT 75 85 71 87 / 50 40 10 0
LCH WATCHES/WARNINGS/ADVISORIES
LA...NONE.
TX...NONE.
GM...NONE.
PUBLIC...24
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