380
FXUS64 KLIX 221818
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
118 PM CDT Wed Jul 22 2026

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

.KEY MESSAGES...
Updated at 114 PM CDT Wed Jul 22 2026

- Abnormal impacts from Tropical Storm Bertha: hot, dry and
  breezy conditions inland while with minimal rainfall. Extreme
  heat warning this afternoon with heat indices 110-115 degrees
  along and west of I- 55.

- Windier conditions along with coastal flooding (mainly south of
  I- 10). Tropical Storm Watches and Warnings are in place for
  coastal areas along and south of I-10.

- Impactful heat conditions subside late week but return this
  weekend and persist beyond that.

&&

.SHORT TERM...
(Now through Saturday night)
Issued at 114 PM CDT Wed Jul 22 2026

Tropical Storm Bertha remains a highly sheared and poorly organized
system just south of the Mississippi coast late this morning. The
exposed low-level center was moving west-northwest at only 5 knots,
while essentially all persistent deep convection has been displaced
well southwest of the center by strong northeasterly shear. Regional
radar continues to show the bulk of the meaningful rainfall over the
coastal waters south of southeast Louisiana, with only scattered
light showers wrapping near the center and into coastal Mississippi.
Surface observations reflect the strong north-to-south gradient in
impacts: winds remain generally 10 to 15 mph inland, while coastal
Mississippi has been reporting north-northeast gusts around 30 mph
along with low ceilings and light rain.

The 12Z KLIX sounding helps explain the unusual combination of
tropical weather near the coast and extreme heat farther inland.
Precipitable water was 2.22 inches, which is around or above the
90th percentile for late July. Moisture was concentrated through the
lower boundary layer, with progressively drier air intrusion aloft
and strong northeasterly flow through much of the column. Thus, the
sounding supports highly efficient warm-rain processes where
persistent lift can be maintained, but moisture alone will not
overcome the subsidence, weak lapse rates, and displaced forcing
across most of the CWA today. Rain chances today remain somewhat
counterintuitive for a tropical cyclone. Most land areas should see
only isolated to scattered showers, generally 20 to 40 percent, with
the best coverage along the immediate lower Louisiana coast, coastal
Mississippi near the circulation center. Even there, convection will
remain uneven and largely dependent on shallow bands rotating around
the exposed circulation. The high precipitable-water environment
could support brief heavy rainfall, but the relatively quick
steering flow and poor convective organization should limit the
duration and spatial extent of heavy rain. This is consistent with
the WPC Marginal Risk, which specifically notes that most of
Berthas significant rainfall remains displaced over the open Gulf.

Heat remains a concern through this afternoon. Subsidence and drying
north of Bertha, combined with limited rain coverage is allowing
temperatures to reach mid/upper 90s. With dewpoints generally in the
middle and upper 70s, peak heat indices of 110 to 115 degrees remain
reasonable. The caveat is this is for areas NOT under Bertha`s
circulation center cloud shield. Have canceled heat products early
for those portions of the CWA.

Berthas low-level center is forecast to move into southeast
Louisiana coast this afternoon before continuing westward Thursday.
Given the increasing land interaction and persistent deep-layer
shear, its becoming increasingly more likely that the circulation
will become elongated and increasingly trough-like rather than
remain a compact tropical cyclone. NHC maintains a minimal tropical
storm through Thursday, but also explicitly notes that Bertha could
weaken to a depression or remnant low sooner. The important local
forecast feature will therefore be the residual low-level
convergence axis rather than the exact designation of the system.
As that elongated circulation stretches across the area Thursday,
shower and thunderstorm coverage should increase substantially from
today. Rain chances generally rise into the 50 to 70 percent range,
with the greatest coverage expected near and south of the remnant
trough from the Baton Rouge and New Orleans metros toward coastal
Louisiana. Coastal Mississippi may begin improving somewhat earlier
as the circulation moves west, although enough trailing moisture and
convergence should remain for scattered convection. Locally heavy
rainfall will be possible where repeated development occurs along
the trough, but the exact corridor remains uncertain and a
widespread flooding event is not currently expected. Greater cloud
cover, modestly lower mid level heights, and more increased
convective coverage should hold most highs in the upper 80s to lower
90s, substantially reducing the heat compared with today.

By Friday, the remnants of Bertha should be west of the forecast
area and dissipating while the Four Corners broad scale  ridge begins
expanding southeastward toward the lower Mississippi Valley. Rising
heights, increasing subsidence, and weakening low-level convergence
should produce a fairly quick reduction in rain coverage. Only
isolated convection is expected for the local forecast area with the
best chance along sea breeze boundaries. Highs should recover into
the lower and middle 90s, but the combination of near-normal
temperatures and at least some boundary-layer mixing should keep
heat indices below today advisory levels.

MEFFER
&&

.LONG TERM...
(Sunday through Tuesday night)
Issued at 114 PM CDT Wed Jul 22 2026

The dominant feature through the extended period will be expansion
of the upper-level ridge currently centered over the Four Corners
region. A fairly summertime typical weak surface ridge becomes
established across the central Gulf Coast. Increasing subsidence and
minimal deep-layer moisture should suppress most diurnal convection.
Rain chances will subsequently fall to around 10 to 20 percent
Saturday and remain near or below 20 percent from Sunday through
Tuesday. The limited convection that does develop should be confined
mainly to the immediate coast or a locally enhanced seabreeze
boundaries.

Temperatures will increase incrementally as the ridge strengthens.
Highs Saturday should generally be in the lower to middle 90s,
followed by middle and upper 90s Sunday and Monday. By Tuesday,
upper 90s to around 100 appear increasingly plausible across the
CWA. Heat stress should again become the primary concern beginning
Sunday. Assuming afternoon dewpoints remain in the middle to upper
70s, heat indices should increasingly reach around 108 or higher,
with values potentially exceeding 110 in portions of the area Monday
and Tuesday. Overnight recovery will also become increasingly poor,
with lows generally in the upper 70s and urban or coastal locations
remaining near or above 80 degrees. The trend supports an increasing
potential for heat headlines Sunday onward, with the possibility of
more significant heat early next week if both temperatures and
dewpoints verify near the warmer end of guidance.

MEFFER
&&

.AVIATION...
(18Z TAFS)
Issued at 114 PM CDT Wed Jul 22 2026

A range of ceilings can be expected based on terminal location in
relation Tropical Storm Bertha. Visible satellite shows a well
defined cloud shield confined quite close to the center. Attm,
terminals along an east of a line from KHDC to KMSY and eastward are
underneath that and seeing IFR to MVFR ceilings. Points west are VFR
to MVFR. Scattered SHRA may briefly reduce visibility and ceilings
as the center of Bertha tracks west today and tonight, although
coverage should remain uneven. North to northeast winds will remain
gusty at the southern terminals, with gusts around 20 to 30 knots
possible before winds gradually veer east and southeast as the
center moves west. The risk of temporary flight restrictions
increases area-wide late tonight and Thursday as Berthas
circulation elongates into a low-level trough and shower coverage
becomes more numerous. Wind direction may become variable for a time
near the remnant circulation before becoming southerly.

MEFFER
&&

.MARINE...
Issued at 114 PM CDT Wed Jul 22 2026

Tropical Storm Bertha will continue moving west towards the
southeast Louisiana coast, entering inland portions of the CWA this
afternoon. Winds across portions of the open waters remain around 20
to 30 knots with occasional tropical-storm-force gusts, particularly
in near the exposed center of circulation. Seas will remain rough
and elevated, with substantial variability depending on location
relative to the center. Conditions should gradually improve from
east to west tonight and Thursday as Bertha weakens and moves toward
south-central and southwest Louisiana.

Scattered to numerous showers and thunderstorms will remain possible
Thursday, producing locally higher winds, rough seas, frequent
lightning, and sharply reduced visibility. Elevated water levels
along the Gulf-facing coast and within the tidal lakes will be slow
to subside until the persistent onshore component weakens. A more
substantial return toward normal water levels and marine conditions
is expected late Thursday into Friday. By Friday and through the
weekend, a weak surface ridge should support winds generally 10
knots or less and waves or seas near 2 feet or less, aside from
isolated afternoon thunderstorms.

MEFFER
&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Tropical Storm Watch for LAZ058-094-096.

     Tropical Storm Warning for LAZ064-070-076>078-087-089>093-095-
     097>100.

     Extreme Heat Warning until 8 PM CDT this evening for LAZ034>037-
     046>048-056>058-071-081>086.

     Coastal Flood Advisory until 4 AM CDT Thursday for LAZ058-077-
     080-082-093-095-097-098.

     Coastal Flood Warning until 4 AM CDT Thursday for LAZ070-076-078-
     091.

GM...Tropical Storm Watch for GMZ529.

     Tropical Storm Warning for GMZ531>536-541-543-551-553-554-557-
     570-572-575-577.

MS...Tropical Storm Watch for MSZ083>085.

     Tropical Storm Warning for MSZ086>088.

     Extreme Heat Warning until 8 PM CDT this evening for MSZ068>070.

     Coastal Flood Warning until 4 AM CDT Thursday for MSZ086>088.

GM...     Tropical Storm Warning for GMZ532>536-541-543-551-553-554-557-
     570-572-575-577.

&&

$$

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