National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS64 KLIX 211827
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
127 PM CDT Sun Apr 21 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday night)
Issued at 323 AM CDT Sun Apr 21 2024

A fast moving positively tilted shortwave trough axis will
continue to sweep through the region this morning. Further down
toward the surface, a cold front is quickly transiting south and
east across the coastal waters and will be in the offshore waters
by late morning. In the mid-levels, a more west-southwest flow
regime will continue to induce isentropic forcing over the shallow
cold pool near the surface. This mid-level forcing will combine
with the strong upper level forcing from the trough axis to
produce scattered to numerous showers over most of the forecast
area through the morning hours. Only areas along the immediate
coast of Louisiana and in the offshore waters will see sufficient
instability to produce widely scattered thunderstorm activity this
morning. As the shortwave trough axis shifts to the east this
afternoon and evening, increasing negative vorticity advection and
subsidence will allow skies to clear from northwest to southeast.
By late this evening, dry conditions and mainly clear skies are
expected to be in place. Temperatures will be substantially colder
as a 925mb thermal trough axis slides through the region with
highs only warming into the 60s this afternoon. Lows will cool
into the low to mid 40s north of the 10/12 corridor and the upper
40s and lower 50s south of the 10/12 corridor.

Deep layer northwest flow in the mid and upper levels will
dominate the Gulf South tomorrow and Tuesday, and this will keep
a cool and dry airmass in place. Highs will recover slightly due
to greater solar insolation, but readings will still be below
average in the lower 70s tomorrow. Tomorrow night will see strong
radiational cooling occur as conditions remain clear and dry. Lows
will fall back into the low to mid 40s north of the 10/12 corridor
and the upper 40s and lower 50s further to the south. By Tuesday,
a surface high will transition to the east of the area, and this
will allow for return flow off the Gulf to take hold. Dewpoints
will gradually begin to rise and this will allow lows on Tuesday
night to be a good 10 degrees warmer than those seen Monday night.
Daytime highs will also continue to modify beneath mainly clear
skies with readings climbing back to more normal levels in the mid
to upper 70s.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 323 AM CDT Sun Apr 21 2024

A very persistent longwave ridge axis will move into the Gulf
South on Wednesday and remain in place through Saturday. This
strong ridging aloft will induce a strong mid-level capping
inversion that will effectively kill any rain chances in the
extended period even as dewpoints rise into the 60s on the back of
sustained onshore flow in the low levels. At most, some fair
weather cumulus development will be possible each day. Conditions
still look favorable for some radiation fog to form late
Wednesday night into Thursday morning, but boundary layer flow
should increase above favorable limits by Thursday and Friday
nights. Instead, rounds of low stratus will form on Thursday and
Friday nights before mixing out into the scattered cumulus field
by the afternoon. In terms of temperatures, strong deep layer
subsidence will favor warmer daytime highs through the extended
period. Highs will start off in the upper 70s and lower 80s on
Wednesday, but will increase into the mid to upper 80s by Friday
and Saturday. Lows will also warm from the upper 50s and lower 60s
Wednesday night into the upper 60s and lower 70s by Friday night
as dewpoints continue to rise.

&&

.AVIATION...
(18Z TAFS)
Issued at 109 PM CDT Sun Apr 21 2024

Showers have pushed south of all terminals with post frontal dry
air advection continued to decrease low level clouds. Most
terminals are VFR now and all should be within the next few hours
or less. Northerly winds will remain elevated around 10 to 15
knots with higher gusts. Sites closer to water are observing gusts
over 20 knots. Tonight, winds will further increase from the
north at NEW as the cold pool moves over the warm lake waters with
sustained winds of 20 knots and gusts up to 30 knots expected
through the end of the TAF cycle. Clear skies, albeit possibly
thin cirrus clouds at times, expected the rest of the TAF period.
Elevated north winds will continue Monday as high pressure builds
in from the north.

&&

.MARINE...
Issued at 323 AM CDT Sun Apr 21 2024

Colder air moving into the area behind a front will support
stronger offshore flow of 15 to 25 knots today into tonight. Seas
will respond to these stronger winds and will increase to 3 to 5
feet over the open waters by tonight. As high pressure begins to
build over the waters tomorrow, winds will gradually relax below
15 knots and also turn more easterly. By Tuesday, the surface high
will be positioned over the eastern Gulf, and this will allow for
a persistent onshore flow pattern to take hold. Onshore winds of
10 to 15 knots are expected on Tuesday and Wednesday, but a slight
tightening of the pressure gradient in response to a low in Texas
on Thursday and Friday should push winds back into exercise
caution levels of 15 to 20 knots. Seas will respond and increase
from 1 to 2 feet to 2 to 4 feet by the end of the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  43  70  43  78 /   0   0   0   0
BTR  47  72  48  79 /   0   0   0   0
ASD  47  73  46  78 /   0   0   0   0
MSY  55  72  56  78 /   0   0   0   0
GPT  49  73  52  75 /   0   0   0   0
PQL  48  73  45  76 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Small Craft Advisory until 10 AM CDT Monday for GMZ530-532-534-
     536-538-550-552-555-557-570-572-575-577.

MS...None.
GM...Small Craft Advisory until 10 AM CDT Monday for GMZ532-534-536-
     538-550-552-555-557-570-572-575-577.

&&

$$

SHORT TERM...PG
LONG TERM....PG
AVIATION...ME
MARINE...PG