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

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FXUS64 KLIX 190157 AAB
AFDLIX

Area Forecast Discussion...UPDATED
National Weather Service New Orleans LA
857 PM CDT Mon Mar 18 2024

...NEW UPDATE...

.UPDATE...
Issued at 851 PM CDT Mon Mar 18 2024

With the loss of daytime heating, temperatures across the forecast
area are starting to drop into the upper 40s and 50s respectively.
The 00z sounding shows quite a mixed boundary layer. Now that the
temperatures are falling, a radiation inversion will develop as
some rad cooling takes place with the lack of cloudiness.
Gradient winds are still elevated closer to the coast, however, we
are starting to see winds decrease to 5kts or less across
southwest MS...basically where the Freeze Warning is currently in
effect. There is still questions in terms of surface winds a tier
or two of counties/parishes south of the current freeze headlines.
Think along the immediate coast winds will remain just high
enough to eliminate the potential max radiational cooling,
however, if winds calm over night along the I12 corridor in LA or
north of I10 along the MS Gulf Coast, some MinTs may flirt with
freezing, especially along the Pearl River or Pascagoula/Escatawpa
basins. For now the ongoing forecast seems to be on track so we
will continue to keep the wind forecast untouched, but a short
fused freeze headline may be needed along the I12 corridor in SE
LA and north of I10 along the MS Gulf Coast. (Frye)


&&

.SHORT TERM...
(This evening through Wednesday night)
Issued at 400 PM CDT Mon Mar 18 2024

Drier air and plenty of sunshine has allowed us to warm up today a
bit more than was expected. Much of the area was in the upper 60s
and low 70s today. PW is around 0.5-0.6 inches this afternoon
thanks to the drier low-level air mentioned earlier. That is
around the 25th percentile for today, showing how abnormally dry
it is out there. The tightened pressure gradient behind the cold
front that passed this morning has caused some gusty northerly
winds this afternoon with the help of thermal mixing.

The center of the surface high trailing the front will move over
the area late tonight and into Tuesday morning. This will help
back winds down for Tuesday. Although surface winds seems to back
down, cold-air advection still seems apparent Tuesday morning, so
lows were bumped down from NBM across the area. This led to
freezing temperatures across much of SW MS and the adjacent
Florida parishes. Freezing temps will only last for maybe and hour
or two because as soon as the sun comes up, we will warm up pretty
rapidly. You can thank even drier air for that because the drier
the air, the more of a diurnal temperature curve you get. Thanks
to much drier 850mb air, PW will drop all the way down to 0.2
inches tomorrow, rivaling the daily min for that day of 0.25
inches.

Like was mentioned before, the aforementioned drier air on
Tuesday will cause air to rapidly warm throughout the day. So,
that coupled with the clear skies expected on Tuesday, cause the
temps to get bumped up from NBM using a blend of NBM 75th and 90th
percentile. The dry air and sunshine will also cause dewpoints to
mix out efficiently at the surface, so NBM 10th percentile was
used for that as well. This drops our RH to below 25 percent for
most of the area, so be careful burning tomorrow if you do.
Thankfully, since the center of the surface high will be overhead,
winds will not be an issue for fires.

By Wednesday, the surface high slides to the east and we get
return flow setting up. This will moisten us back up where PW will
get back above 0.5 inches, although still abnormally dry. This
also allows temps to continue to get warmer and actually feel like
Spring for the first day of spring!

&&

.LONG TERM...
(Thursday through Sunday night)
Issued at 400 PM CDT Mon Mar 18 2024

Thursday, another upper level system is expected to influence the
area as a low moves through the southeast US, which will enhance
rain chances Thursday into Friday morning. Southerly surface winds
ahead of the frontal system will help to advect warmer and moist
air into the region, enhancing instability as well. There are
still quite a few uncertainties in the model consensus in the mid-
range forecast, mostly surrounding the amount of rainfall
expected. Some are drier while others show more of a potential for
training. Our forecast has been trending a little drier to be
more in line with growing trends in the forecast. PoPs are still
in the 30-50% range.

After the system moves through, ridging will dominate the upper
level pattern and conditions will be dry Friday through the weekend.
Northerly surface winds Friday through Saturday night will help keep
conditions a little less humid, but highs will still be pushing
80 degrees this weekend. Sunday will be mostly a transition day
for the atmosphere as surface winds shift back to southerly and
moisture is reintroduced to the atmosphere. MSW

&&

.AVIATION...
(00Z TAFS)
Issued at 633 PM CDT Mon Mar 18 2024

VFR conditions will prevail. Otherwise, northerly winds will start
out gusty, but should decrease through the night and early Tuesday
morning. Eventually the winds will become variable with little if
any flight concerns through the cycle. (Frye)

&&

.MARINE...
Issued at 400 PM CDT Mon Mar 18 2024

Gusty northerly winds behind the cold front has caused hazardous
seas today through tomorrow morning. Once the center of the
surface highs gets overhead, the winds significantly back down
below impact thresholds, and benign conditions stick through the
end of the week. There is another shot of rain Thursday with the
next system, but there is still some uncertainty on timing and
location of the rain.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  31  62  38  70 /   0   0   0   0
BTR  37  65  43  72 /   0   0   0   0
ASD  35  63  42  70 /   0   0   0   0
MSY  43  60  47  70 /   0   0   0   0
GPT  37  60  43  68 /   0   0   0   0
PQL  35  63  39  71 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Freeze Warning from 3 AM to 8 AM CDT Tuesday for LAZ034>037-039-
     071.

GM...Small Craft Advisory until 7 AM CDT Tuesday for GMZ530-532-534-
     536-538-550-552-555-557-570-572-575-577.

MS...Freeze Warning from 3 AM to 8 AM CDT Tuesday for MSZ068>071-077.

GM...Small Craft Advisory until 7 AM CDT Tuesday for GMZ532-534-536-
     538-550-552-555-557-570-572-575-577.

&&

$$

UPDATE...RDF
SHORT TERM...JZ
LONG TERM....MSW
AVIATION...RDF
MARINE...JZ


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