Modeste, Louisiana Weather Forecast Discussion

563
FXUS64 KLIX 031132 AAA
AFDLIX
Area Forecast Discussion...UPDATED
National Weather Service New Orleans LA
632 AM CDT Fri Oct 3 2025
...NEW AVIATION...
.SHORT TERM...
(Today through Saturday)
Issued at 1206 AM CDT Fri Oct 3 2025
Mid-level circulation center over southeast Louisiana this evening,
with another over the Bahamas. Ridging extended from west Texas to
the northern Plains States, with a deep trough approaching the
Pacific coast. At the surface, strong high pressure was centered
near Boston, with low pressure over the Bay of Campeche. The
pressure gradient between the two was producing moderate easterly
winds across our marine areas. Scattered showers and storms were
being detected, mainly offshore of the southeast Louisiana coast at
mid-evening.
The upper feature over southeast Louisiana isn`t going much of
anywhere through Saturday, perhaps maybe a bit of a westward drift,
as ridging builds to the north of the area. Precipitable water
values ranged from about the 75th percentile across southeast
portions of the area to the 25th percentile across the northwest
during the evening, and current forecast guidance doesn`t really
show that changing much through Saturday afternoon.
Most guidance shows little, if any, precipitation north of the
Interstate 10 corridor through Saturday afternoon, and forecast
soundings support that with instability being rather limited over
land. Little change in precipitation probabilities from the previous
forecast package through Saturday afternoon, with rainfall amounts
exceeding one half inch generally remaining near and south of a
Belle Chasse to Houma line, with any very heavy rain likely
remaining well offshore.
Additional cloud cover and scattered precipitation are likely to
hold high temperatures in the middle 80s across most of the area
both today and Saturday, but could approach 90 across extreme
northwest sections northwest of a McComb to Baton Rouge line.
With the strong high to the northeast and low pressure over the Bay
of Campeche, the easterly low level flow over the coastal waters
will continue to push water up on the east facing shorelines
resulting in minor coastal flooding concerns starting this afternoon
and continuing through Saturday into Sunday. Water levels of 1 to 2
feet above normally dry ground will be possible in the normally
prone locations during high tide cycles around midday.
&&
.LONG TERM...
(Saturday night through Thursday)
Issued at 1206 AM CDT Fri Oct 3 2025
The upper circulation is expected to remain near or over the area
through Monday before upper ridging pushes it out of the area. No
indications that a well defined surface low pressure circulation
moves onshore based on current wind forecasts of east to northeast
winds and the forecast pressure pattern. The 00z run of the GFS does
show a weak surface circulation (1010 mb) near Southwest Pass Sunday
afternoon, but keeps it offshore.
Moisture levels do increase on Sunday as compared to Saturday, but
there is disagreement as to how much. 00z GFS BUFR soundings show
precipitable water values well above the 90th percentile for much of
the area Sunday (in excess of 2 inches), with the NAM and other
modeling that go out that far closer to the 75th percentile or so.
This looks to be because the forecast 850 and 925 mb flow is onshore
and stronger (20-30 knots) than the previous runs. Most guidance
with the exception of the RRFS doesn`t support this. We`ll have to
monitor these trends, because if banding of precipitation sets up in
the wrong place (urban areas), it could produce problems, even
though it`s been dry in most areas over the last month. If there is
going to be a day with significant rainfall in more than isolated
locations, it`ll be Sunday, as the mid levels begin to dry out on
Monday. From Monday onward, it appears rain chances won`t be much
more than 20 to 30 percent, if that much. Any threat of severe
weather looks to be extremely low.
High temperatures look to be in the lower and middle 80s for most of
the area on Sunday, then gradually creep up to the upper 80s by
Tuesday through Thursday. However, if heavier rain does set up
Sunday, those areas might not get out of the 70s. Overnight lows in
the middle and upper 60s into the lower 70s away from marine
influences.
The coastal flood threat could continue through Sunday`s high tide
cycle before winds diminish enough to reduce the threat.
Additionally, the astronomical tide ranges will be diminishing.
&&
.AVIATION...
(12Z TAFS)
Issued at 621 AM CDT Fri Oct 3 2025
Mostly VFR conditions for most of the terminals through the
period. The best rain potential will be along and south of the I10
corridor mostly over the local Gulf waters. Otherwise moderate
easterly or ENE flow will continue to develop. (Frye)
&&
.MARINE...
Issued at 1206 AM CDT Fri Oct 3 2025
A seasonably strong pressure gradient between low pressure in the
Bay of Campeche and high pressure over New England will bring
hazardous conditions to the waters through the weekend. A prolonged
easterly wind of 15 to 25 knots will persist through Sunday.  The
combination of wind waves and swell from a long fetch across the
eastern Gulf will produce rough seas of 6 to 10 feet in the open
Gulf waters and 3 to 6 feet in the sounds and tidal lakes. A Small
Craft Advisory will remain in effect for all of the open Gulf waters
and the tidal sounds, as well as Lake Borgne through Sunday evening
due to these expected rough conditions. Small Craft Exercise Caution
headlines may be necessary at times for Lakes Pontchartrain and
Maurepas. Conditions will gradually improve Monday into Tuesday as
high pressure becomes more centered over the area.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB  85  65  86  66 /   0   0   0  10
BTR  87  67  88  69 /  10   0  10  10
ASD  84  66  83  67 /  10  10  20  30
MSY  84  73  84  74 /  30  20  30  30
GPT  84  69  84  69 /  10  10  20  40
PQL  84  66  83  68 /  10  10  20  40
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Advisory from noon today to 6 PM CDT Sunday for
     LAZ069-070-076-078.
GM...Small Craft Advisory until 6 PM CDT Sunday for GMZ532-534-536-
     538-555-557-575-577.
Small Craft Advisory until 6 AM CDT Sunday for GMZ550-552-570-
     572.
MS...Coastal Flood Advisory from noon today to 6 PM CDT Sunday for
     MSZ086.
GM...Small Craft Advisory until 6 PM CDT Sunday for GMZ534-536-538-
     555-557-575-577.
Small Craft Advisory until 6 AM CDT Sunday for GMZ552-570-572.
&&
$$
SHORT TERM...RW
LONG TERM....RW
AVIATION...RDF
MARINE...RW

NWS LIX Office Area Forecast Discussion