549 
FXUS64 KLCH 080355
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
955 PM CST Mon Dec 7 2020

.DISCUSSION...
Sfc obs/satellite imagery show clear skies prevailing over the
forecast area at this time as a dry nwrly flow aloft lingers while
sfc high pressure continues building over the region. Along with
the clear skies, sfc winds have decoupled which will help lead to
a good radiative cooling night...expect temps down to the 30s for
most of the forecast area overnight. Additionally, the cold temps
and calm winds should allow for the formation of patchy fog over
the colder nern zones prior to sunrise.

Although the bulk of the inherited grids/zones are doing just fine
at the moment, will be issuing an update to modify the cloud cover
to better reflect going conditions.

25

&&

.PREV DISCUSSION... /issued 528 PM CST Mon Dec 7 2020/ 

DISCUSSION...
08/00Z TAF Issuance.

AVIATION...
A dry airmass in place will maintain VFR/SKC conditions through
the period. NW winds will become light and vrbl overnight, then
back more W to SW Tues morning, with speeds around 6-7 KT or less.

24

PREV DISCUSSION... /issued 339 PM CST Mon Dec 7 2020/ 

DISCUSSION...
A quiet and pleasant day to start the week with high pressure and
CAA yielding sunny skies and afternoon highs about 5 degrees or 
so below climatological normals. Modest radiational cooling sets
in overnight as clear skies are maintained and winds become light,
so some areas of patchy frost in central Louisiana will be
a possibility. A gradual warming trend is expected through the 
week, with return flow ushering moisture back in by Thursday. 
Quiet weather and clear skies continue through this period.

By the Thursday/Friday time frame, an upper level low translating
across the Desert Southwest begins to become absorbed in the 
longer wave trough digging into the central CONUS. At the moment,
models seem to be in pretty good agreement on timing with an
associated cold frontal boundary advancing through the region 
late Friday and into the early morning hours on Saturday. Shear 
profiles look decent through FROPA, but right now a lack of 
instability is evident, which should preclude a severe threat. 
Still something to keep an eye on should models hint at more 
instability working into the region in subsequent model cycles.
Current forecast indicating roughly around 0.5 to 1.0 inches of 
QPF with the system, which seems reasonable. However, any 
embedded convection or a general slow down of the system could 
result in those amounts increasing a bit.

Models diverge a bit on what to expect after the front, but in
general indicate the front will likely stall somewhere in the
Gulf while the upper trough remains sluggish to lift from the east
CONUS. Given a good bit of uncertainty for this part of the
forecast, opted to just remain with a general model blend and trim
back PoPs which will largely be dependent on the aforementioned 
features. 

50

MARINE...
Offshore flow will continue to diminish in magnitude this evening,
becoming fairly light around 5 to 10 kts overnight. High pressure
will dominate the forecast through mid-week with fairly light 
westerly winds gradually shifting onshore toward the latter half 
of the week as the next frontal boundary approaches Friday into 
Saturday. These onshore winds will be a bit more moderate Friday
and Saturday ahead of the front. Showers and thunderstorms will 
be a possibility along with the aforementioned frontal boundary, 
with offshore winds once again developing in its wake.

50

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  34  64  38  67 /   0   0   0   0 
LCH  41  64  43  68 /   0   0   0   0 
LFT  39  63  43  68 /   0   0   0   0 
BPT  40  65  44  70 /   0   0   0   0 

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&

$$