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

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FXUS64 KLIX 230850
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
350 AM CDT Mon May 23 2022

.SYNOPSIS...

Low pressure that had been over the Gulf of Mexico on Sunday has
moved inland and was located over southwest Alabama at 3 AM CDT. A
weak frontal boundary was located somewhere near Interstate 10 at
the same time. Southwesterly mid level flow continued across much
of the western Gulf Coast, with the next shortwave in that flow
moving across the Rio Grande Valley. A stronger upper trough was
noted to the west of that from Wyoming into the Four Corners area.

At 3 AM CDT...most of the concentrated precipitation associated
with the Gulf low had moved northeastward into Alabama, although
patches of light rain remained over southeast Louisiana and
isolated showers were mainly over the coastal waters. Temperatures
at 3 AM were generally in the lower and middle 70s.

&&

.SHORT TERM (through Wednesday)...

For the next 36 hours or so, the threat of organized severe
weather or excessive rainfall has diminished, but definitely is
not zero. Differential heating is likely to aid the development of
scattered convection today, but there`s no organized forcing.
Precipitable water values remain high, between 1.6 and 1.9 inches,
based on GFS forecast soundings, so at least isolated heavy
rainfall is still a concern. Most of the overnight hours tonight
should be dry in much of the area. The shortwave near the Rio
Grande this morning will approach the area toward sunrise Tuesday
and may reignite thunderstorms, but it`s more likely that they
hold off until late Tuesday morning or afternoon. Forecast
precipitable water values are actually lower on Tuesday, closer to
1.5 inches. This shortwave should have pushed east of the area
prior to sunset Tuesday.

The remaining threat will be associated with the primary trough
that will be lifting through the Great Plains Wednesday into
Thursday. The airmass will still be rather unstable with CAPE
values in excess of 3000 J/kg possible, although 0-6 km shear will
be lacking. Precipitable water values will be around 1.6 inches,
so at least brief heavy rainfall will remain possible. Of the next
3 days, Wednesday looks to be the day that will have the most
significant weather interruptions.

Temperature forecasts will primarily depend on having the correct
interpretation of convective development. The GFS numbers for
today would only indicate a 5 or 6 degree recovery from current
levels, and any sunshine at all will likely drive readings into
the mid 80s. Tuesday will be the warmest day of the 3, as it is
the driest, but the ECMWF numbers appear a little too warm.
Accepted the high temperature guidance for Wednesday, but if the
trough arrives quicker than forecast, current highs will be too
warm. Not much range in overnight lows, and have accepted those
values. 35

&&

.LONG TERM (Wednesday night and beyond)...

Forecast gets a little less active in the extended and actually a
tad cooler but that will be short lived, as we are approaching
Summer. Good agreement with the ensemble means showing an actual
cold front pushing all the way through the region on Thursday.
With a bulk of this forecast focused on the next 3 days the NBM
values look good.

After multiple disturbances move through the southwest flow bringing
the region a few rounds of storms we may finally be on the way to
drying out but that will be after one more round of storms early
Tuesday. L/W trough over the central CONUS will finally start to
slide east Wednesday night and Thursday however, things may trend a
little slower over the coming days if the ridge in the western
Atlantic is as strong as the models are advertising. That ridge
should continue to block things or at the least keep the transition
a little slower. The problem is the models have been very persistent
with Thursday being the day conditions start to change. Even with
the timing differences here and there Thursday and Thursday night
seemed to be the prevailing solution. As the highly amplified trough
axis slides through the region Thursday it will help to drive a late
Spring bona fide cold front through the area. Drier air will work
in behind it and conditions will be pleasant for late May.

Northwest flow should continue through Friday before ridging starts
to build back into the area this weekend. Clouds could hang around
Thursday night and Friday as the h85 thermal trough remains over the
area through Friday morning. Morning lows will have the greatest
impact as dewpoints will fall into the 50s and then slowly recover
late this weekend. /CAB/

&&

.AVIATION (valid through 12z Tuesday)...

In the very near term (prior to sunrise), have removed TSRA from
all terminals except KGPT, as we don`t really expect convection to
reignite over land until a few hours after sunrise. However, MVFR
to IFR ceilings are still likely at most terminals during that
period. Latest HRRR solutions indicate that TSRA will again become
possible at most terminals by midday. Don`t feel that areal
coverage will be large enough to carry any more than VCTS at this
time, but any direct impacts will certainly produce MVFR
ceilings/visibilities with potentially IFR or lower visibilities.
Most activity should dissipate with sunset, but flight
restrictions due to ceilings will again be likely prior to sunrise
Tuesday. 35

&&

.MARINE...

Unsettled weather will continue across the Lakes and marine areas
as a cold front stall across SE LA. Showers and thunderstorms
will stay in the forecast through at least late Wednesday or
early Thursday. A long S to SE fetch will develop as high
pressure sits off the east coast of FL and low pressure forms over
Central TX on Tuesday. Moderate seas of 3 to 5 feet will be
common in the outer waters. A stronger cold front will moves
through the coastal waters late Wednesday night into Thursday
with widespread storms. High pressure will return with improved
marine conditions for the holiday weekend. 35

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  83  67  85  70 /  30  10  70  30
BTR  85  69  86  71 /  30  10  70  40
ASD  86  69  88  72 /  50  30  60  30
MSY  84  73  88  75 /  60  30  50  30
GPT  84  72  85  75 /  60  40  60  30
PQL  84  70  86  72 /  60  50  60  30

&&

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

$$


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