293
FXUS64 KLIX 171145
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
645 AM CDT Mon Jun 17 2024

...New AVIATION...

.UPDATE...
Issued at 348 AM CDT Mon Jun 17 2024

A final look at marine observations required an adjustment to the
Small Craft Advisory over western waters to initiate the advisory
immediately. No other changes made.

&&

.SHORT TERM...
(Today through Tuesday)
Issued at 338 AM CDT Mon Jun 17 2024

Upper ridging centered over the Carolinas this morning, with a
second ridge over Baja California. A weakness between the two is
combining with the Central American Gyre to pump deep moisture
northward across the local area. An area of low pressure is
expected to develop over the Bay of Campeche over the next couple
of days associated with the Gyre. The impulse that produced
showers and storms across the area on Sunday has moved north of
the area, but the next impulse is already noted on water vapor
imagery over the central Gulf of Mexico moving northward. The 00z
LIX sounding last evening already showed precipitable water values
in excess of 2 inches, which is above the 90th percentile
climatologically.

Already seeing radar returns on LCH radar over their coastal
waters, and expect to start seeing them on the HDC radar over the
next hour or so. Deep moisture is expected to remain in place
today with precipitable water values remaining in the 1.9 to 2.2
range, which will be in the top 10 percent climatologically for
mid June. Expect pretty widespread areal coverage of precipitation
today, which will produce locally heavy downpours (2 inches per
hour possible). Not everyone will see rainfall that heavy, but if
one occurs over an urban or poor drainage area, it will have the
potential to cause localized flash flooding. Over the course of
the day, areal average rainfall of 1 to 2 inches appears likely,
with spot higher totals. However, don`t expect widespread totals
heavy enough to justify a Flood Watch at this time. Similar to
Sunday, expect a significant decrease in areal coverage of
showers/storms toward sunset this evening, through the overnight
hours. Another surge of showers and storms is expected on Tuesday,
with precipitable water values similar to today. However, the
impulse driving that round is expected to be further west, more
toward western Louisiana, where the axis of heavier rainfall is
expected.

The pressure gradient between the expected low pressure over the
Bay of Campeche and high pressure over the Carolinas will bring an
increase in surface winds across coastal areas, especially on
Tuesday. A Wind Advisory may be necessary across coastal areas
near and to the south of Interstate 10 on Tuesday. The persistent
southeast winds expected will cause higher tide levels along east
and south facing shorelines as early as late tonight, and don`t
see a need for adjustments to the Coastal Flood Advisory at this
time.

Regarding temperatures, can`t rule out a few spots touching 90
degrees today or tomorrow, but the high areal coverage of showers
and storms should hold highs in most areas in the 80s. With the
deep moisture remaining in place, overnight lows are going to have
a tough time dropping below the mid 70s tonight.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 338 AM CDT Mon Jun 17 2024

Wednesday and Thursday are expected to be comparatively dry as
upper ridging builds back in from the east briefly. The airmass
only dries out somewhat with precipitable water values falling to
about 1.8 inches and no large scale forcing. We should be back to
more of a summertime convective regime with overnight/early
morning marine convection and isolated to scattered afternoon
precipitation over land. Beyond Thursday, details remain uncertain
regarding an inverted trough to our east. At this point, it
appears that significant precipitation associated with the trough
should remain to the east of the local area for the weekend.

Even with the drier weather Tuesday night/Wednesday, the
southeasterly winds will continue pushing water toward the coast,
with water levels somewhat higher Wednesday than Tuesday. At this
point, it appears that we should stay at advisory levels, but
can`t entirely rule out the need for a Coastal Flood Warning in a
few of the more vulnerable locations. The tidal lakes will
probably need to be added in a later forecast package, as they may
have issues by Wednesday or Wednesday night.

High temperatures Wednesday and Thursday will creep up a bit from
today and tomorrow to around 90, then into the lower and middle
90s over the weekend. Overnight lows will continue to be above
normal.

&&

.AVIATION...
(12Z TAFS)
Issued at 634 AM CDT Mon Jun 17 2024

Most terminals VFR at issuance time this morning, with the
exception of KMCB, where IFR ceilings were in place. Convection
was rather isolated at 11z, but expect areal coverage to blossom
in the next few hours as surface heating kicks in. MVFR ceilings
may become predominant by 15z. SHRA will be main weather for the
next few hours with the threat of TSRA at pretty much all
terminals by midday. Areal coverage should be sufficient for TEMPO
during the afternoon at all terminals with IFR or lower
visibilities and MVFR ceilings. While wind gusts in excess of 30
knots are possible with the strongest cells, not high enough
confidence to carry in most terminals. Areal coverage will
diminish toward 00z Tuesday, with little or no precipitation
between about 02z and 10z. MVFR to IFR ceilings may return toward
sunrise Tuesday.

Sustained winds near 15 knots possible during much of the daytime
hours today before diminishing this evening. With low pressure
expected to develop over or near the Bay of Campeche later today
or tomorrow, stronger sustained winds are anticipated during the
daytime hours tomorrow, with gusts of 25 to 30 knots not out of
the question by mid-morning.

&&

.MARINE...
Issued at 338 AM CDT Mon Jun 17 2024

Have noted a few locations seeing sustained winds near or just
above 20 knots this morning. Small Craft Exercise Caution
headlines will be replaced with Small Craft Advisories over most
waters at 12z, although it may take until midday for some waters
to get near 20 knots sustained. Advisory level conditions expected
to continue overnight tonight into at least Tuesday morning. Not
out of the question that we could reach gale levels over portions
of the waters Tuesday or Wednesday, but we will allow oncoming
shift to take another look. The long fetch of these winds will
produce a swell train over the open waters which is likely to push
seas to at least 9 to 12 feet over the open waters by Tuesday
night into Wednesday. Hazardous to dangerous conditions should be
anticipated for much of the work week, especially over the open
waters, with not much improvement expected until perhaps Friday.

As noted above, with the prolonged southeasterly winds, east and
south facing shorelines will see increased water levels beginning
overnight tonight, and a Coastal Flood Advisory will remain in
effect as issued previously, and will likely eventually need
extended into Thursday. Coastal Flood Warnings may be necessary
for more sensitive spots by Tuesday night or Wednesday. Will hold
off on tidal lakes for this run, as it appears their main water
concerns may hold off until Wednesday night or Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  86  72  84  72 /  80  30  40  10
BTR  88  77  87  76 /  90  30  60  10
ASD  87  76  87  76 /  90  40  60  20
MSY  87  80  87  81 /  90  40  80  30
GPT  88  77  88  77 /  80  40  60  30
PQL  90  76  91  76 /  80  40  40  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Advisory from 1 AM Tuesday to 4 PM CDT Wednesday
     for LAZ066>070-076-078.

GM...Small Craft Advisory from 7 AM Tuesday to 7 AM CDT Thursday for
     GMZ530-532-534.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ536-538-555-
     557-575-577.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ550-552-570-
     572.

MS...Coastal Flood Advisory from 1 AM Tuesday to 4 PM CDT Wednesday
     for MSZ086>088.

GM...Small Craft Advisory from 7 AM Tuesday to 7 AM CDT Thursday for
     GMZ532-534.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ538-555-557-
     575-577.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ552-570-572.

&&

$$

SHORT TERM...RW
LONG TERM....RW
AVIATION...RW
MARINE...RW