720
FXUS64 KLIX 070906
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
406 AM CDT Mon Sep 7 2026

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

.KEY MESSAGES...
Updated at 358 AM CDT Mon Sep 7 2026

- Scattered showers and storms are forecast throughout the
  forecast period. The overall severe weather threat will be low,
  but one or two storms could become strong to severe.

- Primary threats with storms will be strong wind gusts, frequent
  lightning and periods of heavy rain leading to localized flash
  flooding.

- Above normal temperatures expected most of the 7-Day forecast
  period. Afternoon heat indices will generally range from 100 to
  108 degrees. Heat Advisories have been issued for portions of
  the region on Labor Day.

&&

.SHORT TERM...
(Now through Thursday)
Issued at 358 AM CDT Mon Sep 7 2026

The main forecast challenges today through midweek will be how much
convection develops this afternoon, the associated conditional
damaging wind threat, and the transition toward a wetter pattern
Tuesday through Thursday. Early this morning, the region remains
along the southern and southeastern periphery of a somewhat ragged
mid-level ridge centered over the Southern Plains, while troughing
over the eastern CONUS continues to push somewhat drier air toward
the region from the northeast. A notable moisture gradient will be
evident today, with forecast PW values generally around 1.7 to 1.9
inches within the drier portion of the airmass and increasing to
around 2.1 to 2.2 inches along and south of the I-10/12 corridors.
Convective coverage remains the biggest uncertainty for this Labor
Day 2026. Large-scale forcing is weak and CAM guidance remains
rather inconsistent, ranging from very little development in some
RRFS solutions to considerably more afternoon convection in the HRRR
and other CAMs. Given strong daytime heating, abundant low-level
moisture, the nearby moisture gradient and weak mesoscale
boundaries, scattered afternoon thunderstorms still appear
reasonable, with somewhat greater coverage expected across the more
deeply moist southern and eastern portions of the CWA. While storm
coverage itself is uncertain, any storms that do develop will have
the potential to become rather intense. Forecast soundings indicate
a pronounced drier layer aloft with DCAPE generally on the order of
800 to 1000 J/kg in portions of the area. Combined with strong
instability, this will favor efficient downward momentum transport
and evaporative cooling within heavier cores. With weak vertical
shear, storms should remain primarily pulse-type and poorly
organized, but an isolated damaging downburst will be possible
during the mid to late afternoon and early evening. Thus, the severe
threat is conditional primarily on whether sufficient convective
coverage can develop, with damaging wind the main concern.
The same storms will also be capable of heavy rainfall. The highest
rainfall efficiency are more likely south of the I-10/12 corridors
and the coast where PW values exceed 2 inches. Weak steering flow
and interactions between sea breeze/outflow boundaries could allow a
few storms to move slowly or repeatedly affect the same locations.
However, with no strong or persistent focusing mechanism and
uncertainty regarding overall storm coverage, any flooding threat
today should remain localized and mainly confined to poor drainage
locations or areas receiving repeated heavy downpours. Prior to
convection, temperatures should climb into the middle and upper 90s
across much of the area. Combined with the humid boundary layer,
peak heat index values of 108 to around 112 degrees are expected
across much of southeast Louisiana and southern Mississippi. A Heat
Advisory remains in effect from 11 AM through 7 PM. The eventual
coverage and timing of convection will be important, as earlier
development would cut off heating before heat advisory conditions
occur. Convection should diminish fairly quickly inland this evening
with loss of heating, although some activity may linger near the
coast and over the marine waters overnight.

On Tuesday, the center of the upper ridge shifts farther east and
southeast toward Arkansas while the eastern side of the ridge
temporarily expands eastward as the eastern CONUS trough moves into
the western Atlantic. Over the CWA, we sit right on the southern
edge of the ridge. Global models suggest a weakness, possibly
inverted trough tracking west across the northern Gulf Coast. This
feature, combined with ample moisture throughout the column, should
allow thunderstorm coverage to begin increasing, especially across
southeast Louisiana and the coastal counties where moisture will be
deepest. Northern portions of the CWA may be somewhat slower to see
the increase depending on moisture depth(could still have PW`s
around 1.8"). For temps, increasing convection and cloud cover
should begin taking the edge off the heat compared with today but
still looking at highs in the 90s. Heat indices will still commonly
reach or exceed 105 degrees but am less confident that a heat
advisory will need to be issued for a second consecutive day.

A more noticeable pattern change starts takes shape Wednesday and
Thursday. The ridge becomes increasingly flattened as stronger
northern stream troughing progresses eastward across the northern-
central US and shortwave energy on its southern flank digs toward
the mid Mississippi Valley. By Thursday, this effectively creates a
weakness or split within the ridge over or near the region. Deep
moisture and loss of subsidence should result in much greater
convective coverage. POPs generally increase into the 50 to 80
percent range, with the greatest coverage favored along the coastal
areas along/south of I-10. With PW values remaining high and
steering flow relatively weak, locally heavy rainfall will become
increasingly common Wednesday and Thursday. Repeated convection
along lingering outflow boundaries could produce localized flooding,
especially in urban and poor drainage locations, although confidence
remains low in identifying any particular corridor for excessive
totals this far out. Greater cloud cover and earlier convective
development should also hold afternoon temperatures closer to
seasonal normals, generally around 90 for Wednesday and Thursday.

MEFFER
&&

.LONG TERM...
(Thursday night through Sunday)
Issued at 358 AM CDT Mon Sep 7 2026

Definitely looks like we should see a pattern shift heading into the
end of the work week and next weekend. Operational models and
associated ensemble means all show our ridge being suppressed prior
to Thursday night and then a trough which will be dropping southeast
splitting the ridge in two over the Lower MS Valley and southeastern
CONUS which continue to allow for what looks like decent coverage of
showers and thunderstorms daily. Latest NBM is in agreement and and
is generally showing near 60-70% over the southern half of the CWA
each day and near 50% across southwestern MS. With what the models
are showing see no reason to deviate from that.

As mentioned the ridge will already be suppressed but Thursday night
as the first in a series of northern stream s/w works across the
central and northern CONUS our ridge will get split over the Lower
MS Valley and southeastern CONUS. We will see the center of one
ridge well off to the west over extreme western TX, NM, and
northwestern Mexico while a large broad ridge will extend across the
western Atlantic over the Bahamas and into the southwestern Gulf
(Bay of Campeche). This trough axis/weakness will remain over the
area Friday through Sunday. That alone would allow for the potential
of daily storms however, given that the trough won`t work through
the area and really be more of a weakness we will not see the
moisture get suppressed as PW`s will likely remain in the 1.9 to 2.1
range. At the sfc There will be a weak front move east-southeast
through the central CONUS and into the Mid MS Valley and then
towards the southeastern CONUS but with the bulk of the mid lvl
forcing mainly racing east and no real trough digging into the
southeastern CONUS there will be very little support with this front
and now most if not all of the guidance suggest this front will not
make it anywhere close to the region. That could be a positive thing
as that front could lead to more problems if it makes it closer to
the area. It will not have the support to continue to push south
into the Gulf or deeper. If it could that would likely help to clear
out some of the moisture but in all honesty it probably would stall
over or near the area and that would bring about the concerns for
more focused heavy rain. So, with weakening front looking like it
will hang up well to our north we will still see things more focused
on outflow boundaries and lake/sea breezes and that helps to keep
the potential for heavy rain and flashing flooding more isolated and
not across a larger area. Luckily the upper level setup doesn`t look
quite as favorable for very efficient rain until maybe more Sunday
but that still doesn`t indicate any real strong upper level
diffluence or divergence. /CAB/

&&

.AVIATION...
(06Z TAFS)
Issued at 358 AM CDT Mon Sep 7 2026

VFR conditions dominate the forecast through at least mid morning. A
CU field should begin developing across the region around 14-16Z
with bases likely ~5kft. The most realistic potential aviation
impact is afternoon thunderstorms. However, confidence is lower
than normal in terms of if convection will actually develop.
Greatest chance for any storms is at KNEW, KMSY and KHUM, where
deeper moisture will be in place. PROB30 TSRA groups remain
appropriate for those terminals generally during the 18-24Z
period. Coverage around KBTR, KMCB and KASD looks more isolated
and confidence in direct terminal impacts is too low for a PROB30
at this time. Drier air aloft increases the odds of strong
downburst winds with stronger cells today. In addition, any storm
could produce IFR visibility, lower ceilings and sudden wind
shifts at terminals.

MEFFER
&&

.MARINE...
Issued at 358 AM CDT Mon Sep 7 2026

The pressure gradient will remain weak through the period with
generally benign background marine conditions. Winds should mostly
remain around 10 knots or less with seas around 1 to 2 feet through
the short term. The primary marine concern will continue to be
thunderstorms. Deep moisture remaining over the northern Gulf will
favor scattered convection over the coastal waters, particularly
during the late night and morning hours before the focus shifts
inland with the sea breeze during the afternoon. Coverage should
remain elevated through Monday as the upper trough approaches and
weakens subsidence, despite the backdoor front likely remaining east
of the local waters. Daily thunderstorm chances continue through the
remainder of the week and may increase somewhat late in the week as
the upper ridge weakens and troughing becomes more influential.
Outside of convection, conditions should remain well below advisory
criteria. The stronger storms will remain capable of locally gusty
winds and briefly higher waves.

MEFFER
&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from 11 AM this morning to 7 PM CDT this evening
     for LAZ034>037-039-046>048-056>058-064-071-076>087-089>100.

GM...None.
MS...Heat Advisory from 11 AM this morning to 7 PM CDT this evening
     for MSZ068>071-077-083-086.

GM...None.
&&

$$

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