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

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FXUS64 KLIX 222056
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
356 PM CDT Thu Oct 22 2020

.DISCUSSION...
Bottom line - the calendar may say it`s late October, but the
weather didn`t get the memo as temperatures, especially overnight
lows, will remain well above normal through most of the forecast
period. Highs most days will reach the low to mid 80s with lows
in the mid 60s to even lower 70s. For reference, normal highs this
time of year are generally in the mid 70s with lows in the low to
mid 50s.

Outside of areas that received heavy rainfall associated with
Delta early this month, most of the area is running at a
precipitation deficit for October. With October being one of the
driest months of the year in our area, this means many areas have
received less than an inch of rain over the past several weeks.
The good news is we have relatively high rain chances on tap for
tomorrow as convergence between a decaying easterly wave and an
approaching "cold" front provides a focus for showers and storms.
The bad news is that even with the high rain chances, most places
are likely to only pick up a couple tenths of an inch of rain.
The normal caveat of isolated locations could pick up more
significant totals, especially if multiple thunderstorms affect
the same area.

The previously mentioned "cold" front will move through the area
from northwest to southeast during the late afternoon and through
the evening. Unfortunately we`re only expecting a few degrees of
cooling behind the front. It`s the difference between highs in the
mid 80s Friday and lower 80s Saturday. Similarly lows will drop
from the upper 60s and lower 70s tonight into the mid to upper 60s
Friday and Saturday nights. This nominal cool down will be short-
lived as winds turn easterly again by Sunday and southeasterly by
Monday in response to high pressure moving eastward.

By Sunday, a longwave trough will be digging into the desert
southwest. A surface low pressure and cold front will form in
response and will move eastward along with the upper trough
through the week. There continue to be significant differences
between the GFS and Euro concerning this front. The GFS continues
to be more progressive and stronger with the front while the Euro
is slower and weaker. The GFS pushes the front well into the Gulf,
with the base of the trough swinging all the way south into the
northern Gulf. Meanwhile the Euro indicates substantial flattening
of the trough as it moves through the lower Mississippi Valley
and lifts northeastward before the front really pushes into the
Gulf.

IF the front moves through the area with any gusto as indicated by
the GFS, it would likely be next Thursday, while any impacts from
the slower front in the Euro would be even farther out in time.
All that being said, for the time being, have trended slightly
warmer than the GFS, but not quite as warm as the Euro, though
this may be optimistic given recent history of fronts not quite
being as strong as expected by the time they reach this part of
the country.

&&

.AVIATION...
VFR conditions will generally prevail through the first part of
tonight. Low cigs and patchy fog will be possible during the late
night and early morning hours, with MVFR cigs lasting through at
least the first part of the day Friday. Rain chances increase
tomorrow, with showers and isolated thunderstorms spreading inland
throughout the day. Expect east to southeast winds to persist
until a weak cold front moves through during the late afternoon
through the evening.

&&

.MARINE...
Persistent easterly winds will continue to result in higher than
normal tides tonight and some minor/nuisance coastal flooding
will be possible across coastal areas from Port Fourchon eastward
through Hancock County. Convergence between a decaying easterly
wave and an approaching cold front will lead to enhanced rain
chances on Friday. The front will briefly result in weak offshore
winds Saturday, but as high pressure quickly moves eastward, winds
will shift back to the east and then southeast Sunday into Monday.
The next frontal system is expected to approach the area late next
week, but there is some uncertainty regarding how far into the
Gulf it will get.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  69  83  67  80 /  10  60  20  10
BTR  70  85  67  81 /  10  60  20  10
ASD  70  84  68  82 /  10  70  20  20
MSY  72  84  70  82 /  10  70  20  10
GPT  71  82  70  82 /  10  70  30  20
PQL  70  83  69  81 /  10  70  30  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Advisory from midnight tonight to noon CDT Friday
     for LAZ040-062-064-067>070.

GM...None.
MS...Coastal Flood Advisory from midnight tonight to noon CDT Friday
     for MSZ080.

GM...None.
&&

$$

95/DM


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