Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 231135
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
635 AM CDT Sat Sep 23 2017

.DISCUSSION...
For the 23/12Z TAF Issuance.

&&

.AVIATION...
Light winds and clear skies has allowed some patchy fog to form
with possible MVFR visibilities until about 23/14Z. Remainder of
the looks like mainly VFR conditions will prevail. A few showers
or storms will be possible during daytime heating. At this point
the probability looks too low to place in terminals.

Rua

&&

.PREV DISCUSSION... /issued 428 AM CDT Sat Sep 23 2017/

DISCUSSION...

Short Term...Today through Monday...

An analysis of this morning`s 500 hPa heights show a 588 dam ridge
centered over the Mississippi River Valley and an longwave trough
centered over the west coast of the US. The overall upper level
pattern remains relatively unchanged compared to 24 hours ago.
Therefore, expect fairly similar weather to yesterday with
temperatures running from 5 to 10 degrees above normal for the end
of September. Daytime mixing should keep dewpoints in check and
limit maximum heat index values to around 100 degrees. However, a
few locations could approach closer to 105 for an hour or two
late in the afternoon. There will once again be a slight chance
for showers and thunderstorms from the mid morning through the
afternoon hours.

The upper level ridge and associated surface high pressure are
forecast to gradually progress northeastward through Monday.
Increasing moisture return will result in a slight increase in
rainfall chances on Sunday and Monday. However, rainfall chances
will still mainly be around 30%-40% as mesoscale boundaries and
thermals will be the primary forcing mechanisms for any showers or
thunderstorms.

Long Term...Tuesday through Friday...

An overall shift in the upper level height pattern is expected to
occur during the second half of the week. This will result in a
ridge over the western two-thirds of the CONUS and trough centered
over the NE. This pattern will allow for an area of high pressure
to build southward from northern Canada. A weak cold front
associated with this area of high pressure is expected to push
through the region during the day on Thursday. Model guidance is
indicating that this should be a relatively dry frontal passage
with only slight chances for showers and thunderstorms. Behind the
cold front, 850 hPa temperature anomalies from the NAEFS/GFS are
around -1 sigma which would suggest that a major cool down
shouldn`t be expected. However, days with highs only in the low to mid
80s will be appreciated given the recent stretch of above normal
temperatures.

MARINE...

Weak high pressure will remain in place over the coastal waters
into early next week. This will result in light easterly to
southeasterly winds each day. There will also be a slight chance
for showers and thunderstorms mainly from the morning through the
middle afternoon hours each day.

The area of high pressure is expected to shift northeastward by
the end of the week and allow a weak cold front to progress
through the area during Thursday into Friday. With the passage of
the front, a shift to predominately offshore winds is expected
with increasing wind speeds and wave heights.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  93  69  92  69 /  20  10  20  10
LCH  91  73  90  72 /  20  10  20  10
LFT  92  72  91  72 /  20  10  30  10
BPT  91  73  90  72 /  20  10  20  10

&&

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

$$


AVIATION...07


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