Area Forecast Discussion
Issued by NWS Lake Charles, LA

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000
FXUS64 KLCH 220555
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1155 PM CST Mon Jan 21 2019

.DISCUSSION...
06Z TAFS

&&

.AVIATION...
Ceilings have remained VFR through the evening at all sites with
the exception of BPT where they have been highly variable between
VFR and IFR. Expect VFR conditions to continue to prevail at
remaining sites through the early morning with a gradual and
intermittent lowering to MVFR by this afternoon. Meanwhile, expect
BPT to prevail MVFR with intermittent periods of both VFR and IFR.

A tightening pressure gradient between high pressure extending
across the east coast and a deepening low over the Oklahoma
panhandle. Winds in the 10 to 15 knot range with higher gusts will
continue through the night before increasing further during the
afternoon.

Isolated to scattered showers will begin to develop during the
afternoon hours before increasing through the evening and
overnight with the approach of a cold front from the west. The
line of storms expected with the front as well as the frontal
passage will occur Wednesday morning just beyond this forecast
package.

Jones

&&

.PREV DISCUSSION... /issued 906 PM CST Mon Jan 21 2019/

UPDATE...
Gradient tightening up some across the forecast area tonight
between a surface high over the eastern Great Lakes and a
developing low over eastern Colorado. This is allowing a
freshening of the southeast flow, which in turn is helping to
increase moisture and clouds. Precipitable water on the 22/00Z
upper air sounding from KLCH was only up to 0.40 inches. Most of
the moisture was also between 2k and 5k feet with the low level RH
over 80 percent and the mid level RH less than 20 percent. Mainly
an increase in cloud levels between these heights are expected for
the remainder of the night, with maybe a few light streamer type
showers developing below the "cap" overnight. The increase in low
level moisture and clouds will also keep temperatures up tonight
with readings pretty much staying steady or increasing during the
night from what they are currently at.

Just made a few adjustments to the current forecast. Mainly to
delay any significant shower development until the overnight, and
also have hourly temperatures and dew points reflect current
observations and short term guidance.

Rua

PREV DISCUSSION... /issued 524 PM CST Mon Jan 21 2019/

DISCUSSION...
00Z TAFS

AVIATION...
Two distinct cloud decks have enshrouded the area this evening.
A low level deck lifting north out of the gulf will alternate
between VFR and MVFR this evening becoming more exclusively MVFR
overnight into Tuesday. Aloft, cirrostratus will continue to
stream from west to east in the mid level flow.

A pressure gradient at the surface between high pressure over the
east coast and a deepening low centered over Colorado. This will
keep southeasterly winds elevated through the night before
increasing further Tuesday afternoon in advance of an approaching
cold front. Isolated to scattered showers will begin to develop
across the region after 18Z Tuesday in association with this cold
front although this development is expected to be somewhat
erratic.

Jones

PREV DISCUSSION... /issued 345 PM CST Mon Jan 21 2019/

DISCUSSION...
Mid-afternoon sfc analysis shows high pressure centered over the
Midwest and ridging sswwd, while lower pressures are noted over
the Rockies...combo of these features is providing for an
increasing onshore low-level flow over the forecast area. Temps
have responded with readings in the mid/upper 50s across the
entire area at this time, while dew points range from the upper
30s to upper 40s. Water vapor imagery shows the region under weak
ridging while trof axes are noted over the wrn Atlantic and
digging into the Rockies. Pacific moisture continues spilling over
the region with visible imagery showing plenty of cirrus
overhead...while the increasing low-level moisture has led to
quite a bit of low cloudiness, especially across the wrn 1/2 of
the forecast area. Despite the cloud cover, regional 88Ds remain
PPINE.

No significant changes were made to the grids/zones this
afternoon. The mid/upper-level storm system approaching the
Rockies will continue pushing ewd through tomorrow. The
increasing srly flow through the column will lead to rapid
moistening with PWAT values quickly pushing over an inch by early
Tuesday...and a few showers look possible in the developing WAA
regime late tonight. As the shortwave aloft continues trekking
ewd, good lift will continue to overspread the region, resulting
in additional shower development through Tuesday. The system will
also help with sfc low development over the Plains, eventually
pulling the low and associated cold front through the area late
tomorrow night into Wednesday morning. Widespread shower activity
is expected to accompany the system...forecast soundings continue
to indicate little if any instability despite the warming sfc
temps, thus sticking with just showers at this time. Precip will
end from west-to-east through the day on Wednesday with perhaps a
few post-frontal showers lingering into Wednesday evening over
extreme lower Acadiana.

With a progressive pattern in place, the end of the work week
looks dry as Canadian high pressure builds over, then past the
forecast area. Another round of cold temps look on tap with good
CAA holding afternoon temps in the 40s across much of the area
Wednesday...then highs capping in the 50s on Thursday. Morning
lows are progged mostly in the 30s Thursday and Friday mornings,
although some upper 20s look possible across the extreme nrn areas
Thursday morning. Another boundary is progged to slip through on
Friday although with no real return flow developing in front of
it, expect this front to pass dry.

The next storm system aloft is progged to pass the region next
weekend, accompanied by yet another sfc boundary. Moisture return
ahead of this boundary looks sufficient for at least widely
scattered shower development Saturday into early Sunday. Will have
to watch later model runs to see if the cooler air can overtake
the moisture and allow for any winter-type precip mainly across
the nern zones...for now, only liquid rain is expected.

MARINE...
An elevated srly flow is developing over the coastal waters and
caution headlines were inserted earlier today. Some seas to 7 feet
look possible over the far outer waters late tonight into
tomorrow...for now, have not issued any SCAs but did highlight the
possibility of these higher seas in the HWO. The previous trend of
winds shifting to a nrly direction and increasing again on
Wednesday behind the cold frontal passage still looks good.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  54  48  68  43 /   0  20  50  80
LCH  57  53  70  46 /   0  20  40  70
LFT  57  52  69  51 /   0  10  40  60
BPT  58  54  69  43 /   0  20  30  90

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Exercise Caution through Tuesday morning for GMZ450-
     452-455-470-472-475.

&&

$$


AVIATION...66


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