Area Forecast Discussion Issued by NWS New Orleans/Baton Rouge, LA
000
FXUS64 KLIX 140847
AFDLIX
Area Forecast Discussion
National Weather Service New Orleans LA
347 AM CDT Thu Mar 14 2024
...New SHORT TERM, LONG TERM, MARINE...
.SHORT TERM...
(Today through Friday)
Issued at 340 AM CDT Thu Mar 14 2024
Shortwave ridging was noted from Lake Michigan to Alabama early
this morning, with an upper low cutting off well to the west near
Las Vegas. This is producing southwesterly mid-level flow across
the western Gulf of Mexico. There were a couple of weak shortwaves
moving through that flow. At the surface, high pressure extended
from south of Bermuda into Georgia. Low pressure over eastern
Kansas had a cold front southwestward into west Texas. Locally,
there were partly cloudy skies with isolated locations reporting a
little bit of fog. Temperatures at 3 AM CDT ranged from the mid
50s in the Pascagoula area to the mid and upper 60s west of
Interstate 55.
Soundings last evening were fairly dry, with precipitable water
values at LIX, JAN and LCH all around 1.1 inches, primarily due to
moisture below 800 mb. A weakening shortwave over the western Gulf
of Mexico early this morning will move across the local area late
this morning and this afternoon. With onshore flow continuing
today, precipitable water values will increase a bit, to around
1.4 inches. Still quite a bit of dry air aloft, but forecast
soundings indicate that surface based convection will be possible
across most of the area today, with the exception of coastal
areas, where a bit of a marine layer would keep things elevated.
Instantaneous areal coverages will be fairly small, but over the
12 hours daylight period, 30 to 50 percent looks to be fairly
reasonable. Would expect most or all convection to dissipate
around sunset, if not sooner. Shear looks to be very limited,
lowering concerns about severe weather today.
During the overnight period, into early Friday morning, there will
be at least a limited threat of advection fog near the coast as
dew points in the mid and upper 60s move over waters 5-10 degrees
cooler, depending on location. Most guidance isn`t bullish on the
possibility, as the delta between dew points and water
temperatures isn`t nearly as large as a few weeks ago. More likely
to be low stratus, but will acknowledge at least some possibility
of fog.
A northern stream shortwave moving through the Great Lakes will
drag the frontal boundary to our northwest much closer to the area
by midday Friday. This will combine with a shortwave moving
northeastward through the western Gulf to produce another round of
showers and thunderstorms Friday afternoon. Moisture will be a bit
more plentiful on Friday with precipitable water values around
1.6-1.7 inches, which will help with increased areal coverage.
Would expect the best coverage of showers and storms to be across
northern portions of the area (north of Interstate 12), closer to
the front. That`s also where the best shear profiles will be, so
if there`s going to be a strong to severe storm, that`s the most
likely area. Rain amounts are not expected to be extreme,
generally less than an inch, but a few locations could certainly
get more than that.
Temperatures the next couple days potentially 3-5 degrees warmer
than on Wednesday, but unfortunately timed cloud cover or
precipitation could produce a temperature bust in a few areas
&&
.LONG TERM...
(Friday night through Wednesday)
Issued at 340 AM CDT Thu Mar 14 2024
If there is going to be a lull in precipitation this weekend, it
will occur late Friday night and Saturday, in between shortwaves,
and with somewhat lower moisture levels. That is even with the
frontal boundary being somewhere in the local area, but not much
agreement on exactly where that will be. Not confident enough to
pinpoint a large period of dry weather, but we definitely don`t
expect Saturday to be a total washout.
Sunday...however...could be a bit of a different story. A stronger
shortwave will eject out of the southwestern upper low late
Saturday night. Rain and thunderstorms could arrive prior to
sunrise Sunday, and continue for a large portion of the day along
the Interstate 10/12 corridors. Rainfall amounts of 1-2 inches
wouldn`t be a surprise along that corridor, but with some question
as to where in the CWA where the front will be located on Sunday,
it`s probably too early to be too specific.
As the northern trough over the Great Lakes continues to deepen
late in the weekend, the cold front will finally get pushed
offshore Sunday night. That will usher in drier and cooler air for
the first half of the workweek next week.
Regarding temperatures, outside of rainy periods, highs over the
weekend should be in the 70s with overnight lows mainly in the
60s. Behind the front for early next week, temperatures will fall
to near or below normal. Normal for that period would be highs
near 70 and lows near 50, but overnight lows Tuesday and Wednesday
mornings will be in the 40s for much of the area, with a few
readings in the 30s not out of the question in normally cooler
spots. Not quite as confident in the NBM numbers early next week
as the ensembles have more spread than the past week or so, but
not enough ammunition to make significant adjustments.
&&
.AVIATION...
(06Z TAFS)
Issued at 1116 PM CDT Wed Mar 13 2024
VFR conditions will decline to MVFR or IFR through the early
morning hours, especially closer to daybreak as low stratus and
fog develops over terminals. There will be some improvement later
this afternoon for a few sites, but coastal terminals such as HUM
and GPT may hold onto lower VIS/CIGs. A few scattered storms may
also develop during the afternoon or early evening, but timing and
coverage is a little in question at this time. Otherwise, low
stratus and fog will drop categories back to MVFR or IFR
respectively by the end of the cycle. (Frye)
&&
.MARINE...
Issued at 340 AM CDT Thu Mar 14 2024
There will be at least some concerns for mariners during the
forecast period. Thunderstorm potential will be heightened on
Friday and again on Sunday, especially over the protected waters.
A second concern will be the potential for sea fog, with the main
period of concern overnight tonight into Friday. Not enough
confidence in extent or magnitude of fog to go with a pre-emptive
fog advisory at this time. As mentioned in the short term
section, we still have a setup for advection fog, but the threat
does not appear quite as high as a few weeks ago. Thunderstorms
moving through the waters should help to minimize the threat later
Friday. Any gradient wind threat probably won`t come into play
until after the cold front moves through the waters, with any wind
related headlines not expected until perhaps Monday into Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 79 67 76 59 / 40 20 90 40
BTR 86 71 82 65 / 30 20 90 40
ASD 80 67 80 63 / 50 10 80 40
MSY 81 70 80 66 / 50 10 70 40
GPT 75 66 77 63 / 40 10 70 40
PQL 77 65 80 62 / 40 10 60 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
SHORT TERM...RW
LONG TERM....RW
AVIATION...RDF
MARINE...RW