608
FXUS64 KLIX 181820
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
120 PM CDT Sat Jul 18 2026

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.KEY MESSAGES...
Updated at 113 PM CDT Sat Jul 18 2026

- A mostly dry pattern is expected into next week. The primary
  concern will be increasing heat. Heat indices will be in
  advisory criteria today through much of next week. Urban areas
  could approach heat warning criteria Mon-Wed.

- Isolated to widely scattered thunderstorms will begin to develop
  mainly along and east of I55 during the late afternoon hours
  today through the first half of the new week. Even though
  chances of storms will remain low, those that do develop could
  be strong to severe.&&

.SHORT TERM...
(Now through Tuesday night)
Issued at 113 PM CDT Sat Jul 18 2026

Strong subsidence beneath the eastern periphery of the broad CONUS
ridge continues to dominate local conditions early this afternoon.
Radar remains essentially quiet, while visible satellite imagery
shows very little meaningful cloud development across the region.
However, worth noting CU streaks along the Pearl River Basin across
southern MS is bears watching. The 12Z KLIX sounding supports
overarching suppression, with a warm and comparatively dry layer
through roughly 850-700 mb and north to northwest flow generally
around 10 to 20 knots through the mid levels. High convective
temperatures and deep mid layer dry slot should keep development
very sparse. If a storm does develop, a brief strong downdraft
cannot be completely ruled out , but organized severe weather is not
expected.

The lack of appreciable clouds or rainfall will allow temperatures to
climb into the mid and upper 90s across much of the area as the
afternoon progresses. Dewpoints should mix down somewhat inland but
remain high enough for heat-index values generally between 105 and
110 degrees. Overnight temperatures will only fall into the middle
and upper 70s, remaining near 80 around the tidal lakes and
immediate coast. This will provide limited nighttime recovery before
another hot day Sunday.

An upper level trough moving from the Great Lakes into the Northeast
will begin eroding the eastern periphery of the ridge tonight and
Sunday. At the same time, the TUTT low and associated weak surface
trough over the eastern Gulf should drift slowly west or northwest.
There are at least a couple embedded MCVs which could influence the
overall movement. For the CWA, we will remain on the western and
northwestern, generally drier side of this circulation. However, its
moisture envelope should begin edging far enough west to support a
noticeable east-to-west gradient in convective coverage Sunday
afternoon. POPs remain around 30 to 50 percent across coastal
Mississippi, tapering to around 20-30% towards I-55. Rain chances
fall quickly farther west, with only a very small chance around
Baton Rouge and most locations west of I-55. Development should
remain strongly tied to peak heating, the sea breeze, and any
residual outflow boundaries. Convective times well into the 90s
means late day initiation the farther west relative to the CWA.
Storms over the far eastern CWA could produce locally heavy rainfall
and brief gusty winds, but limited coverage and modest steering flow
should prevent a broad heavy-rain problem.

A similar pattern continues Monday as the eastern Gulf circulation
moves little or begins drifting toward the Florida Panhandle. The
highest rain chances will again be across coastal Mississippi and
the far eastern SELA parishes, generally in the 30 to 50 percent
range, with substantially lower chances farther west. A farther-
south or farther-west track would bring clouds and scattered
convection somewhat closer to the New Orleans metro, but most
guidance keeps the deeper moisture and more persistent convection
east of the CWA. Whether the circulation briefly acquires
subtropical or tropical characteristics is of less importance
locally than its eventual track. At present, no meaningful local
wind or coastal impacts are anticipated.

Outside of areas receiving an afternoon storm, highs Sunday and
Monday will again reach the mid and upper 90s. Heat-index values of
105 to 110 degrees will remain common. Therefore, have already
issued a heat advisory for tomorrow.

MEFFER
&&

.LONG TERM...
(Wednesday through Friday night)
Issued at 113 PM CDT Sat Jul 18 2026

The large upper ridge is forecast to remain centered near the
Rockies through the period, with the CWA positioned beneath its
southeastern periphery. The extent to which this ridge builds
southeastward will determine both convective coverage and the
magnitude of the heat. Meanwhile, a series of shortwave troughs
passing through the Great Lakes and Northeast will periodically
attempt to suppress heights across the southeastern CONUS.

Tuesday and Wednesday currently appear to favor a relatively strong
southeastern extension of the ridge. The eastern Gulf disturbance
should be lifting toward the Florida Panhandle or becoming
increasingly diffuse by this time, leaving the deeper tropical
moisture primarily east of the local area. Subsidence and high
convective temperatures should consequently limit rainfall to
isolated afternoon storms, with POPs generally no higher than 30 to
40 percent over the southeastern half of the local forecast area.
Any storms that develop will be capable of brief heavy rainfall and
gusty winds.

This may be the hottest portion of the forecast. Highs should reach
the mid and upper 90s depending on site specific convection and
cloud cover. Those temps with dewpoints in the mid 70s supports
continued widespread heat-index values in the upper 100s to around
110, with localized readings above 110 possible. A period of extreme
heat is well within reach of the current setup and forecast those
days, especially in urban areas.

Forecast confidence decreases from Thursday into next Saturday as
additional shortwaves cross the northeastern United States. Some
guidance maintains a stronger ridge extension across the lower
Mississippi Valley, which would preserve a hotter and mostly dry
pattern. Other solutions weaken the southeastern edge of the ridge
enough to allow a surface trough or weak front to settle toward the
northeaster Gulf Coast. The latter scenario would support scattered
diurnal convection. For now, low-end scattered PoPs in the 20 to 40
percent range appear reasonable.

MEFFER
&&

.AVIATION...
(18Z TAFS)
Issued at 113 PM CDT Sat Jul 18 2026

VFR through this taf cycle. A stray shower would prompt a short term
update requirement to the KGPT TAF but probability is too low to
justify anything with this forecast issuance.

MEFFER
&&

.MARINE...
Issued at 113 PM CDT Sat Jul 18 2026

Surface high pressure centered near and just southeast of the
Mississippi River mouth will maintain a generally west to
northwest wind regime through the weekend. Winds will commonly be
5 to 10 kt over the tidal lakes and sounds, with 10 to 15 kt winds
over the open Gulf waters. The northwest to north flow will be
strongest during the overnight and morning hours before winds
diminish during the afternoons. Seas should generally remain
between 1 and 3 feet, although brief 2 to 4 foot seas will be
possible over the eastern open Gulf waters Saturday.

Isolated to scattered thunderstorms may spread into the eastern
waters tonight through Monday as the eastern Gulf circulation drifts
northward. The greatest coverage should remain east of the
Mississippi River and especially near the Mississippi coastal
waters. Any storms could produce frequent lightning, locally gusty
winds, and briefly higher seas.

The local pressure gradient should relax by the middle of the week
as the northern Gulf surface ridge weakens and broader Atlantic high
pressure begins extending westward. This should support a more
typical summertime pattern of light west to southwest winds
generally around 10 knots or less. Late in the week, one or more
shortwaves crossing the eastern United States may attempt to push a
weak frontal boundary toward the northern Gulf. Confidence that the
boundary reaches the coastal waters is low, but a farther-south
progression could briefly turn winds northerly or northeasterly and
produce a modest increase in speeds.


MEFFER
&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 6 PM CDT this evening for LAZ034>037-039-
     046>048-056>058-064-070-071-076>087-089>100.

     Heat Advisory from 10 AM to 6 PM CDT Sunday for LAZ034>037-039-
     046>048-056>058-064-070-071-076>087-089>100.

GM...None.
MS...Heat Advisory until 6 PM CDT this evening for MSZ068>071-077-
     083>088.

     Heat Advisory from 10 AM to 6 PM CDT Sunday for MSZ068>071-077-
     083>088.

GM...None.
&&

$$

SHORT TERM...ME
LONG TERM....ME
AVIATION...ME
MARINE...ME