Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 291138

Area Forecast Discussion
National Weather Service Lake Charles LA
638 AM CDT Mon May 29 2017

For the 29/12Z TAF issuance.


Complex situation with a surface front nearly stationary across
northeast Texas into northwest Louisiana, meanwhile an outflow
boundary has moved to off the mid Texas coast to the southeast
Louisiana coast. Upper level pattern still shows diffluent flow
aloft with occasional waves of energy. Upper level disturbances
will interact with surface features to produce convection during
the period. However, with outflow boundary offshore, this may tend
to rob instability from land areas. Therefore, will just mention
VCSH for the morning hours, with the possibility of of a few
thunderstorms later this afternoon after 29/19Z, when VCTS will
replace VCSH. Mainly VFR conditions expect away from the storms.



.PREV DISCUSSION... /issued 415 AM CDT Mon May 29 2017/

Regional radar imagery shows overnight convection has moved out
over the coastal waters with areas of light stratiform rain
remaining over Southeast Texas and Southwest Louisiana. These
areas of light rain are expected to diminish over the next few
hours. The cold pool from the overnight convection has introduced
some greater uncertainty to the forecast with regards to
additional precipitation developing later on today. Some of the
most recent CAM guidance keeps much of the area dry through the
rest of the day with only widely scattered convection later this
afternoon. Meanwhile, global guidance continues to indicate more
widespread precipitation today albeit with lighter QPF amounts
than previous runs. Overall, the consensus is that showers and
thunderstorms will still develop later today but could be less
widespread than originally anticipated. Therefore, the PoPs for
today have been lowered slightly for today.

There is a greater model consensus for the development of
precipitation late tonight and through the day on Tuesday as the
stalled surface front continues to undergo frontolysis. Onshore
flow is expected to return late Tuesday into Wednesday and remain
in place for the rest of the week. A steady stream of moisture
from the Gulf of Mexico and Caribbean Sea will result in PWAT
values ranging from +1 to +2 sigma over the region through the
weekend. Therefore, high rainfall chances will exist each day with
convection being driven by the seabreeze and mesoscale boundaries.
Current 7 day rainfall totals for the region look to be on
average 2-4 inches. However, given the prolonged period of above
normal moisture, higher local amounts will be possible.

Showers and thunderstorms are likely over the coastal waters today
and Tuesday with a stalled front nearby. Onshore flow will return
on Wednesday with increasing moisture resulting in chances for
showers and thunderstorms continuing into the weekend. The onshore
flow could also result in elevated seas, particularly over the
outer coastal waters, late Friday through Sunday.


AEX  81  68  80  68 /  60  60  60  40
LCH  82  70  83  71 /  60  50  60  20
LFT  84  72  82  71 /  60  50  60  30
BPT  83  71  83  72 /  60  50  60  20




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