Area Forecast Discussion
Issued by NWS Lake Charles, LA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
945
FXUS64 KLCH 210430
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1130 PM CDT Wed Jun 20 2018

.AVIATION...Showers and storms continue this evening with lower
vis and ceilings in and near convection. Precip chances remain
higher along Highway 165 and to the west. Winds will be generally
light and south to SW through the period, although some storms may
produce brief gusty conditions.


&&

.PREV DISCUSSION... /issued 1006 PM CDT Wed Jun 20 2018/

UPDATE...
Per coordination with the Weather Prediction Center, remnant MCV
over SE TX will enhance precipitation potential in a already
saturated and unstable airmass with PW`s over 2". Have increased
areal rainfall amounts around 1 to 2 inches with the possibility
of 3 to 5 inches in isolated locations across the Flood Watch
areas of Southeast Texas including Jefferson, Orange, Southern
Jasper & Newton counties. Updated forecast and Flood Watch has
been sent.

DML

PREV DISCUSSION... /issued 828 PM CDT Wed Jun 20 2018/

DISCUSSION...
Wx map shows weak high pressure over the SE U.S. this evening,
keeping a moist southeast flow off the Gulf. Not much sfc
reflection of the large trough over coastal TX and N Mexico.
However, weak cyclonic rotation continues roughly between 925mb-500mb
across S TX that`s keeping excellent lift, coupled with PW`s over
2" (2.13" at 00Z LCH sounding), to provide copious amounts of
rainfall where the training convective band sets up. One such band
is continuing to slowly move east across SE TX, mainly northwest
of Beaumont/Orange at this hour. This will continue to feed off of
the moist and unstable air over our region this evening and
overnight. Latest HRRR guidance shows this will likely move
further east into Western Louisiana and unfortunately, over the
remainder of Southeast Texas this evening and overnight. At this
time, looks like rainfall totals of 1" to possibly 2" band could
stay northwest of Beaumont/Orange area, but even the additional
rainfall of 0.5 to possibly 1.0" expected this evening and
overnight could result in drainage problems as the ground remains
absolutely saturated. Flood watch will continue for the hardest
hit counties of Jefferson, Orange, and Southern Jasper & Newton
through 7 AM.

DML

PREV DISCUSSION... /issued 613 PM CDT Wed Jun 20 2018/

AVIATION...Showers and storms can be expected in the area through
the period, however coverage will be higher near KBPT. Lower
ceilings can also be expected overnight and lower vis may occur in
precip. Winds will be south to sw at or less than 10 kts.

PREV DISCUSSION... /issued 441 PM CDT Wed Jun 20 2018/

DISCUSSION...

Short Term...Tonight and Thursday...

Regional radar shows scattered showers and thunderstorms this
afternoon, mainly across Southeast TX and Central LA. Much of this
activity should continue through the afternoon and into this
evening. Latest HiRes guidance continues to push a band of heavier
rain eastward into Southeast Texas late tonight, though there is
still some uncertainty as to when this will move into our area and
what rainfall totals we can expect. Eventually, these showers
should spread into southwest Louisiana and across the area during
the day on Thursday.

After the last several days of heavy rain across southeast Texas,
RFC flash flooding thresholds are still rather low at 2"-3" over
three hours and 3"-4" over six hours. While "official" forecast
totals through tonight are expected to be around or less than one
inch, 12Z HREF guidance indicates the potential for more robust
convection to produce rainfall amounts that will approach flash
flood guidance. Additionally, guidance has preformed poorly over
the past several days with regards to the placement of convective
bands and rainfall amounts. The axis of steadier precipitation is
expected to shift northeast from central Texas during the
overnight hours and any additional heavy rain received overnight
across Southeast Texas has the potential to produce local flash of
preci flooding. Therefore, it was decided to lean on the side of
caution and extend the Flash Flood Watch through Thursday morning
for southeast Texas. Further east across western Calcasieu and
Cameron Parishes, flash flood guidance is running higher and the
likelihood of precipitation exceeding said guidance is lower
resulting in the Watch being cancelled.

RACKLEY

Long Term...Friday through Tuesday...

The upper level low contributing to the heavy rainfall over the
past several days is expected to become integrated with a upper
level trough Thursday with the trough axis shifting east of the
region during the day Friday. The combination of the exiting
trough, the upper level high over the western Atlantic expanding
into the eastern Gulf, and height rises in advance of a digging
shortwave trough from the Pacific northwest will result in weak
ridging across the MS Valley through the weekend into early next
week. This will contribute to decreasing deep layer moisture with
forecast PWAT values of less than 1.5" Friday through Sunday. This
will result in drier conditions and warmer conditions through
Sunday.

Early next week, the digging Pacific shortwave and upper level
ridge will result in a more favorable pattern for return flow and
deep layer moisture will begin to rebound to climatological values
for late June. This will result in a return of the typical diurnal
convection beginning on Monday and continuing through the middle
of the week.

26

MARINE...

Winds and seas will gradually decrease through the evening and
Thursday as the northwest Gulf pressure gradient continues to
relax. Scattered showers and a few thunderstorms will continue
tomorrow before coming to an end Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  75  87  74  94 /  80  60  10  20
LCH  77  85  77  91 /  80  50  10  20
LFT  77  85  76  92 /  20  40  10  20
BPT  77  86  76  91 /  80  50  10  20

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...Flash Flood Watch until 7 AM CDT Thursday for TXZ215-216-261-262.

GM...None.
&&

$$


AVIATION...05



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.