-- Discussion containing changed information from previous version are highlighted. --
436
FXUS64 KLIX 181147
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
647 AM CDT Tue Jun 18 2024

...New AVIATION...

.SHORT TERM...
(Today through Wednesday)
Issued at 405 AM CDT Tue Jun 18 2024

Upper ridging centered over the Carolinas this morning with a
trough over the Rockies and Intermountain West. Still have the low
over the Bay of Campeche that has been designated Potential
Tropical Cyclone One. Still have a fairly significant surface
pressure gradient between the Bermuda High and the circulation
over the Bay of Campeche, although winds haven`t been quite as
strong as anticipated to this point. We continue to be in a very
moist airmass with precipitable water values near or above 2.10
inches, which is above the 90th percentile for mid June and
approaching the daily maxima. Similar to last night, an impulse is
noted on water vapor imagery moving northward through the lower
Mississippi River Valley that took most of the earlier rain with
it. However, we can see on radar, indications of the next impulse
moving into the southern portion of our coastal waters at 3 AM
CDT. Temperatures at that time were mainly ranging from the mid
70s to around 80.

The upper ridge to the east may nudge the cyclonic flow with the
system to our southwest a bit further westward over the next 36
hours. That may not be particularly noticeable in forecast
precipitable water values today, as they remain in excess of 2
inches, but we do expect a noticeable drying across at least the
east half of the area on Wednesday, when precipitable water values
fall to about 1.7 inches. Still expect pretty extensive coverage
of showers and a few storms today, especially once we get some
heating. Most areas should see less than an inch of rain today,
but highly efficient rainfall rates could produce a brief problem
or two. Areal coverage and rainfall amounts on Wednesday should be
somewhat less than today, and shifted westward.

High temperatures today, even with the occasional showers and
storms, should at least get into the 85 to 90 range, and probably
a degree or two higher on Wednesday.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 405 AM CDT Tue Jun 18 2024

The ridging off to our northeast appears to strengthen a bit, and
retrograde westward over the next few days. This suppresses the
circulation to the southwest enough to force it into Mexico. It
also serves to dry our airmass somewhat, especially north of the
Interstate 10/12 corridor. In those areas, we may not see much in
the way of rain for at least Thursday through much of the weekend.
South of there, moisture levels may remain high enough,
precipitable water values in the 1.5 to 1.8 range, to support
isolated to scattered afternoon showers/storms, especially along
lake/sea breeze boundaries. NBM PoPs may be a bit overdone over
the weekend, but current forecast is in agreement with
neighboring offices. As ridging continues to push westward,
moisture levels will again be on the upswing early next week with
a resulting increase in areal coverage of convection.

With the somewhat drier airmass pushing into the area, high
temperatures will return to the lower and middle 90s going into
the weekend. dew points may settle a little lower, but we may get
close to heat advisory criteria over the weekend.

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 635 AM CDT Tue Jun 18 2024

All forecast terminals currently VFR, however, there are some
non-forecast terminals reporting IFR ceilings. Have noted on radar
an increase in areal coverage of SHRA in the nearshore waters over
about the last 45 minutes. As we get a little surface
heating...and it won`t take long...MVFR ceilings will become
prevalent across most or all terminals. Areal coverage of SHRA
will continue to increase, and by 15z or 16z, the threat for TSRA
will increase, with amendments for direct impacts possible. Any
direct impacts will likely produce IFR or lower visibilities and
MVFR ceilings. Threat of TSRA will diminish, if not end entirely,
prior to 00z Wednesday. Beyond 00z, VFR conditions should be the
rule for most of the night, but could see at least a few MVFR to
IFR ceilings toward sunrise Wednesday. Probably will not see as
much development of SHRA/TSRA Wednesday morning as compared to
yesterday or this morning.

Coastal terminals could see wind gusts to 25 to 30 knots during at
least the late morning and afternoon hours today, before relaxing
a bit around sunset. A more general increase in wind speeds is
expected on Wednesday morning as the pressure gradient tightens
somewhat.
-- End Changed Discussion --

&&

.MARINE...
Issued at 405 AM CDT Tue Jun 18 2024

Over the last 24 hours, winds haven`t been quite as strong across
the coastal waters as earlier anticipated, mainly in the 20 to 25
knot range. With PTC One not expected to significantly strengthen,
confidence in gale conditions occurring is not strong enough at
this time to justify gale watches/warnings. Have coordinated with
WFO LCH to hold with strongly worded Small Craft Conditions at
this time. Can`t entirely rule out the eventual need for gales,
especially late tonight or tomorrow. Hazardous conditions are
expected over much of the open waters for the next several days,
however, and Advisories may need to be extended beyond the current
expiration over some or most of the waters. No changes to Coastal
Flood Products at this time, as current forecast levels continue
to be 1-2 feet above normal, which fits advisory criteria.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  85  71  90  71 /  50  10  20   0
BTR  87  76  92  77 /  70  20  40   0
ASD  88  76  90  75 /  70  10  60  10
MSY  88  81  90  81 /  70  20  70  20
GPT  88  77  90  77 /  60  20  50  20
PQL  92  75  93  74 /  40  10  30  20

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
LA...Coastal Flood Advisory until 4 PM CDT Wednesday for LAZ066>070-
     076-078.

GM...Small Craft Advisory until 7 AM CDT Thursday for GMZ530-532-534.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ536-538-550-
     552-555-557-570-572-575-577.

MS...Coastal Flood Advisory until 4 PM CDT Wednesday for MSZ086>088.

GM...Small Craft Advisory until 7 AM CDT Thursday for GMZ532-534.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ538-550-552-
     555-557-570-572-575-577.
-- End Changed Discussion --

&&

$$

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