570
FXUS64 KLCH 051757
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1257 PM CDT Fri Jul 5 2024

...New AVIATION...

.UPDATE...
Issued at 1055 AM CDT Fri Jul 5 2024

Very warm and humid conditions noted across the region this
morning, and morning heat index readings are already climbing well
over 100 degrees. Made some minor adjustments to hourly Td based
on obs and expected trends through the afternoon and this resulted
in some locations reaching advisory criteria across our northern
and eastern zones. Thus, issued a Heat Advisory for this afternoon
for these affected areas.

Beyond this, KLCH radar shows some scattered showers and storms
developing over coastal areas and portions of Acadiana, and
convection is expected to expand in coverage as boundary
interactions combine with heat and moisture. Made some minor
tweaks to PoPs through the rest of the day to align with current
radar and expected trends.

In the meantime, we also continue to monitor the latest on Beryl,
which is currently crossing the Yucatan Peninsula. The storm is
still expected to emerge over the southern Gulf tonight, and
strengthen back into a hurricane as it crosses the southwest Gulf
over the weekend. Latest forecast from NHC shows the system making
landfall along the south TX coast early Monday. Small shifts in
the track forecast will be likely in the coming days and will be
monitored for potential impacts to SE TX and possibly SW LA, but
at this time, the main issues continue to be coastal flooding and
increasing winds/seas over the coastal waters. The potential for
heavy rainfall and flooding will also become a concern, especially
in the early to midweek timeframe as the system moves inland
across TX.

24

&&

.SHORT TERM...
(Today through Sunday night)
Issued at 415 AM CDT Fri Jul 5 2024

Early morning sfc analysis shows high pressure centered over the n-
cntl Gulf maintaining wswrly low-level flow over the region, while a
weak frontal system is noted extending from the OH Valley swwd to
the Red River Valley. Much further south, Hurricane Beryl was nearing
the Yucatan Peninsula. Water vapor imagery shows a flat ridge sitting
over the Gulf Coast at this time while a weak trof is noted over
the center of the country...a series of weak disturbances embedded
in the trof continue to swing by to our north. Satellite imagery
shows quite a bit of cirrus from earlier convection streaming over
the area while sfc obs depict a warm muggy night ongoing. Local
88Ds look devoid of nocturnal convection at this time.

Main adjustments to the forecast as far as today goes was to trim
back on rain chances a bit. Despite very good moisture in place
across the region, blended guidance seemed to be overdoing things
from a POPs perspective over the past 24 hours, with limited
convective development yesterday and now with hardly any typical
summertime nocturnal activity noted on radar. Forecast soundings
indicate a little better moisture today, with PWAT values
basically off the chart...however, categorical rain chances just
seemed high given the weak ridging aloft trying to hold on. CAM
guidance really wasn`t bullish on showers/storms today at last
check. Did allow for the weak front drifting swd into the area
today so didn`t drop POPs as much as I might have...basically kept
all zones in the chance neighborhood for now. Whatever convection
does develop should diminish with sunset, although it is
interesting to note that the CAMs seemed to want to bring in more
rainfall after dark on some sort of resultant outflow/MCS-like
feature...thus held onto small rain chances til about midnight.
Thereafter, we could see the return of coastal nocturnal activity.

Temperature-wise, despite a fair amount of cloud cover and the
potential for rainfall this afternoon, guidance is advertising
highs in the mid 90s across much of the area. With dewpoints
expected to run in the mid 70s, heat index values managed to peak
just below heat advisory criteria today...not to say a few spots
could briefly sneak up to 108 or higher, but not expecting
excessive apparent temps to linger much more than an hour or so.

With the ridging aloft progged to further weaken as we move into
the weekend, along with the persistent good moisture and the
lingering sfc boundary, did allow for rain chances to increase
somewhat across the area on Saturday...although still undercut
blended guidance to a degree. Cooler temps (mainly lower 90s
highs) from the precip/enhanced cloud cover should keep heat index
values from getting anywhere near criteria.

By Sunday, the boundary begins lifting north and out of the area,
leaving daytime heating as the primary driver for convective
development. Elevated rain chances linger in the forecast given
the good moisture expected to still be around, but POPs largely
back into the chance category are being carried this morning.

The latest track from NHC for TC Beryl brings the center of the
storm ashore in the vicinity of KBRO on Sunday as a category 1
hurricane. On this track, the primary impacts on our area
initially appear to be minor coastal flooding on long period
swells coming in off the Gulf.

25

&&

.LONG TERM...
(Monday through Friday)
Issued at 415 AM CDT Fri Jul 5 2024

The extended period forecast is predicated on the track and
intensity of Hurricane Beryl and could be subject to significant
revisions should that track or intensity deviate substantially
from present forecasts. Increasing seas as swells from the system
along with elevated winds over the coastal waters will continue
Monday likely resulting in at least minor coastal flooding.
Meanwhile, a quasistationary upper level trof situated across the
central U.S. with several energy waves translating through it will
continue to provide a focus for higher than climo PoPs Monday.
Forecast soundings depict PWAT values of 2.1 - 2.3 which will
continue to allow for very efficient rain processes and a low end
risk for flash flooding.

By Tuesday, there is a pretty solid consensus between guidance that
the remnants of Beryl will begin lifting across eastern Texas
influenced by the upper trof. As this surge of even higher moisture
content works into the region, a more considerable flash flood
threat will be possible both Tuesday and Wednesday. As is often the
case with decaying and ejecting tropical systems, there is some
indication within guidance that a trailing line of training
convection could set up somewhere across the region late Wednesday
into Thursday. That said, history has shown that attempting to
predict exactly where this will occur is futile until shortly before
it actually gets underway. Regardless, the remnants of Beryl should
be largely clear of the area by late Thursday with the area
returning to more typical, diurnally driven convection by next
weekend.

Jones

&&

.AVIATION...
(18Z TAFS)
Issued at 1247 PM CDT Fri Jul 5 2024

Generally VFR conditions to prevail through the period with SCT
daytime CU sometimes becoming BKN with bases AOA 3500 FT.
Widely scattered to scattered SHRA/TSRA developing early this
afternoon around the area, but potential at any particular airport
warrants no more than VC mention. The exception is KLCH where an
outflow boundary apparent on radar could promote a shower or storm
over the next hour. Convection should diminish an hour or two
after sunset, then redevelop again by late morning Saturday. Winds
will be mostly light and variable through the period.

24

&&

.MARINE...
Issued at 415 AM CDT Fri Jul 5 2024

High pressure aloft will continue to weaken into the weekend,
allowing for another day of diurnally driven showers and
thunderstorms today. Convective coverage looks to become more
widespread over the weekend as ridging overhead fully breaks down.

Light to occasionally moderate onshore flow and low seas will
prevail through the next couple of days. Winds and seas will
begin to increase by Sunday as the pressure gradient begins to
tighten over the coastal region.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  95  74  91  73 /  50  50  70  10
LCH  92  76  90  77 /  40  30  70  20
LFT  94  77  92  78 /  40  50  70  20
BPT  95  77  93  78 /  40  30  70  20

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 7 PM CDT this evening for LAZ027>029-033-044-
     045-055-152>154-252>254.

TX...Heat Advisory until 7 PM CDT this evening for TXZ180-259-260.

GM...None.
&&

$$

SHORT TERM...25
LONG TERM....66
AVIATION...24