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

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
000
FXUS64 KLIX 181140
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
640 AM CDT Mon Mar 18 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 335 AM CDT Mon Mar 18 2024

Southwestern upper low remains over Arizona this morning, while
the northern stream trough extends from Quebec southwestward to
Iowa. An impulse ahead of the troughing could produce a few
sprinkles early this morning, but that`s about it. The cooler,
drier air has been slow to arrive, with dew points only now
starting to drop over southwest Mississippi. Temperatures at 3 AM
CDT ranged from the upper 50s to mid 60s.

The northern stream trough will move rapidly off the East Coast
over the next 24-36 hours, putting the local area under
northwesterly upper flow, if only briefly. Surface high pressure
currently over the Dakotas will dive southward and be centered
near the Louisiana coast by sunset Tuesday.

As the drier air arrives this morning, clouds should diminish and
it`ll become a bit on the breezy side by midday. Humidities will
drop noticeably, to around 30 percent this afternoon. Fortunately,
we got a good bit of rain yesterday, or there would have been a
few fire weather concerns. The coldest air won`t have arrived this
afternoon, and we tend to get a bit of compressional heating
across the northern half of the area with northerly winds, so we
should see some recovery in temperatures this afternoon to close
to 70, with some possibility that might not be warm enough.

Main forecast concern will be overnight lows tonight, with the
potential for temperatures near or below freezing across northern
portions of the area around sunrise Tuesday. It`s been several
weeks since temperatures reached freezing anywhere in the CWA, and
we`re past the mean last freeze date for any of our climate
reporting stations, making freeze products necessary in all areas
when applicable. Main wild card in forecasting overnight lows is
whether the winds become light enough to allow the radiational
cooling necessary to fall to or below freezing. NBM probabilities
continue to show the main threat is to our southwest Mississippi
counties, with the adjacent Florida Parishes of southeast
Louisiana carrying somewhat of a lesser threat. One adjustment to
the Freeze Watch area was to add Pointe Coupee Parish to the watch
to better fit our watch and WFO LCH together. Will keep it as a
watch for now and let the day shift take another look at the
overnight wind forecast before upgrading, if need be.

Considering the source region of the high pressure that will be
centered over us tomorrow was in Canada, it makes sense that
Tuesday highs will be cooler than today, struggling to get much
past 60 in most areas. But at least there will be abundant
sunshine and much less wind.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 335 AM CDT Mon Mar 18 2024

With the northern stream trough losing its effect on the local
area Tuesday night, the upper flow becomes more zonal across the
northern Gulf Coast. Upper troughing moving into the Pacific
Northwest will finally kick the Arizona upper low eastward in a
much weakened state. As it opens up into a wave, it will move
across the area Thursday night into Friday morning. While both the
GFS and ECMWF operational models both develop weak low pressure
over the Gulf of Mexico, the GFS solution is close enough to the
northern Gulf Coast to spread rain into the area, mainly Thursday
and Thursday night. A few rumbles of thunder can`t be ruled out,
but at least for now, severe weather and heavy rainfall appear to
be rather minimal threats.

Once the shortwave reaches the East Coast, it phases with norther
stream energy and closes off again, which will allow high pressure
to become dominant over the lower Mississippi River Valley for the
weekend. That will keep the local area dry with temperatures near
to slightly above normal, with lows generally in the 50s and highs
in the 70s.

&&

.AVIATION...
(12Z TAFS)
Issued at 638 AM CDT Mon Mar 18 2024

VFR conditions expected through the forecast period. Main aviation
concern will be gusty north winds, especially at KNEW and KMSY,
this afternoon and evening, when gusts to 30 knots are possible.

&&

.MARINE...
Issued at 335 AM CDT Mon Mar 18 2024

While winds are short of advisory criteria at present, expect that
to change over the next 6 hours or so, and am not planning any
adjustments to the Small Craft Advisory at this time. A few gusts
to 35 knots aren`t absolutely out of the question this evening,
but not high enough confidence to justify a Gale Warning at this
time. Winds drop off pretty quickly Tuesday morning, with less
hazardous conditions expected for the remainder of the week. The
one limitation to that idea is if low pressure over the Gulf of
Mexico Thursday/Friday develops more than expected. If that
happens, forecast wind speeds at that point would need boosted.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  61  31  62  37 /   0   0   0   0
BTR  65  36  64  43 /   0   0   0   0
ASD  67  34  63  39 /   0   0   0   0
MSY  65  43  60  46 /   0   0   0   0
GPT  68  37  61  41 /   0   0   0   0
PQL  68  33  63  37 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Freeze Watch from late tonight through Tuesday morning 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 Watch from late tonight through Tuesday morning for
     MSZ068>071.

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

&&

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.