Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 291137

Area Forecast Discussion
National Weather Service Lake Charles LA
637 AM CDT Sat Jul 29 2017

Large area of showers and isolated thunderstorms moving through
central Louisiana this morning ahead of a cold front that is
making it`s way thru Louisiana. Looking for storms into AEX
within the hour and into LFT and ARA around 1300z. Ceilings and
vsby with vary as storms pass over sites. This whole system will
move into southwest Louisiana by this afternoon and into southeast
Texas a bit later. TAF sites will becm MVFR w/ storm actvty.


.PREV DISCUSSION... /issued 356 AM CDT Sat Jul 29 2017/

A digging upper level trough over the eastern US will swing an
unusual late July "cold front" through the area this afternoon
through tonight. Convection near the front is already ongoing this
morning across parts of northern Louisiana into central
Mississippi and this activity will gradually sink south through
the day. Forecast soundings from the GFS, EURO and NAM are
indicating a mid and upper level moisture surge as the front
approaches resulting in a dramatic rise in precipitable water
values by this afternoon to near 2.5 inches. This combined with
observations of the ongoing convection has led me to add heavy
rainfall wording to the text forecast products for this afternoon
and tonight. Broad QPF values aren`t all that impressive as the
activity is expected to continue moving from north to south, but
the heavy rainfall could result in some minor street flooding in
the usual urban and poor drainage areas.

As is typical with summer fronts, no significant change in daily
high temperatures will be realized. However, the front will usher
in somewhat drier air dropping dewpoints from the mid to upper
70`s back into the more tolerable upper 60`s. This drier air may
allow overnight lows to drop a few degrees with upper 60`s
possible across parts of central Louisiana and lower 70`s along
the I-10 corridor. The coolest night will be Monday morning.

The airmass begins to moderate by Monday afternoon with dewpoints
slowly increasing. Low end rain chances return Tuesday with rain
chances increasing further for the second half of the week as
another upper trough digs south across the eastern US. The EURO
GFS and Canadian all attempt to swing another frontal system
through the area next weekend although there is considerable
difference with regards to strength and timing. That said, the
simple fact that all three agree on what would be another
unseasonable front at days 7 and 8 is pretty impressive by itself.
Anything to take the edge off the August heat is fine by me.


Scattered to numerous showers and thunderstorms will move over the
coastal waters late this evening into early Sunday morning in
advance of an approaching cold front. Winds behind the front will
turn offshore Sunday and Monday before turning back onshore
Tuesday. Rain chances increase once again by Wednesday through the
end of the week as an upper level trough digs south across the
eastern US.


AEX  89  70  89  69 /  60  20  10  10
LCH  92  77  91  73 /  50  50  10  10
LFT  90  75  90  73 /  50  40  10  10
BPT  93  76  92  72 /  30  70  10  10




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