Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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831
FXUS64 KLIX 170507
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1207 AM CDT Fri Oct 17 2025

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

.KEY MESSAGES...
Updated at 1204 AM CDT Fri Oct 17 2025

 - Rain to return to the forecast this weekend associated with a
   cold front moving through the area.

 - Marginal Risk for severe weather Saturday night for mainly
   northwest portion of the CWA.

&&

.SHORT TERM...
(Today through Saturday)
Issued at 1204 AM CDT Fri Oct 17 2025

Upper ridging centered from southeast Louisiana to Lake Superior
during the evening, with an upper trough from Montana to southern
California. At the surface, the axis of high pressure was from Lake
Huron to near Mobile. Regional upper air soundings during the
evening continued to show precipitable water values near the 25th
percentile (about 0.9 inches). This is reflected in the lack of any
significant cloud cover over land until near the Ohio River. High
temperatures Thursday afternoon were mostly in the upper 80s,
although Bogalusa did reach 91.

The upper ridge will continue to move eastward to the Appalachians
by Saturday afternoon. The trough currently over the Rockies will be
over the Plains States by Saturday afternoon, with a shortwave
moving through the base of the trough over Oklahoma.

As the surface high continues to move eastward, low level wind flow
will become more southerly today, returning moisture to the area.
Moisture levels still won`t be much more than near the 50th
percentile today, and even Saturday morning, but will climb to near
the 75th percentile (1.5 inches) by midday, and could be above the
90th percentile (1.8 inches) by sunset. Shear and instability will
be increasing, but lapse rates will be rather weak (generally <6
C/km). May start to see some isolated convection by Saturday
afternoon, but the main concern for convection will hold off until
after sunset Saturday.

Highs will again be in the 85 to 90 range for most of the area this
afternoon, although the Mississippi coastal counties could be a few
degrees cooler with the winds more fully coming off of cooler
coastal waters (water temps 78-82F). Highs Saturday should be a
couple degrees lower, in the mid 80s, due to cloud cover.

Fog could again be an issue toward sunrise, but not confident enough
to justify any advisories or significant mentions. If it does occur,
it should burn off by about 9 AM CDT.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 1204 AM CDT Fri Oct 17 2025

The shortwave and upper trough to our west Saturday afternoon will
move across the lower Mississippi River Valley overnight Saturday
night. The associated cold front will move across the area late
Saturday night into Sunday morning. Moisture levels are forecast to
be near the 90th percentile (1.8 to 2 inches), about 40 knots of
shear over northern portions of the area, CAPE values around 1000
J/kg, mid level lapse rates around 6.5 C/km, and 0-1km SRH of 150 to
200. That`s certainly enough to monitor the risk for severe weather,
with a Marginal Risk of severe weather in SPC`s outlook for Saturday
night.

Precipitation will be over by midday Sunday, and could be over by
sunrise. A northern stream shortwave moving toward the East Coast
trough axis is expected to push a reinforcing cold front through the
area on Tuesday, but moisture will be extremely limited, and the
front could move through completely dry. Not much on tap for
Wednesday and Thursday as shortwave ridging moves across the area.

High temperatures Sunday will be dependent on how quickly the cloud
cover gets out of the way. If the clouds depart early, prior to
noon, mid and upper 80s aren`t out of the question, especially if
winds turn northerly over the Pearl River Basin.

The 12z Thursday medium range temperature forecasts from the ECMWF
and GFS were in significant disagreement, especially on overnight
lows. Even within the ECMWF ensemble, there was quite a spread on
lows. The most recent NBM numbers are pretty much a compromise
between the operational ECMWF and GFS temperature forecasts.
Hopefully, the significant differences between the ECMWF and GFS
resolve somewhat.

&&

.AVIATION...
(06Z TAFS)
Issued at 1204 AM CDT Fri Oct 17 2025

All terminals VFR at issuance. Really the only forecast issue is
potential for radiation fog toward sunrise. Quite a spread in
visibility forecast guidance. Have used CONSShort in the 09z-15z
period as a compromise with MVFR visibilities at most terminals, but
threat of IFR or lower exists. NBM v4.3 and v5.0 probabilities of
<3SM are less than 20 percent at all forecast terminals at 12z
/near KMSY/KNEW/KHUM/KASD. Conditions should improve quickly by 15z,
with VFR the remainder of the forecast period. Fog probabilities are
a little higher Saturday morning, but thicker cirrus clouds may
preclude that.

&&

.MARINE...
Issued at 1204 AM CDT Fri Oct 17 2025

High pressure centered over the area will continue to gradually
shift to the east and southeast today. Winds will turn more east-
southeasterly 10 to 15 knots through the day in response to the
departing high. A frontal system is expected to slide through the
waters Saturday night and Sunday. Winds may briefly get into the 15
to 20 knot range tonight into Saturday, but currently do not see any
prolonged periods with wind speeds of 20 knots. After the front
moves through on Sunday, winds will shift to the northwest, but
choppy conditions will persist.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  87  65  84  66 /   0   0  40  70
BTR  88  67  87  68 /   0   0  50  60
ASD  85  67  84  67 /   0   0  30  50
MSY  88  72  87  71 /   0   0  40  50
GPT  84  71  84  70 /   0   0  10  50
PQL  86  66  85  68 /   0   0  10  50

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$

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