Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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691
FXUS64 KLIX 270950
AFDLIX

AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
450 AM CDT Sun May 27 2018

.SHORT TERM...
The main focus of this forecast package remains Sub-Tropical Storm
Alberto. Water vapor imagery shows quite a bit of dry mid level air
just west of the storm`s envelope. An outer band from Alberto is
currently moving across coastal waters into southeast Louisiana.
Daytime heating combined with high precipitable water values in
place will promote shower and thunderstorm development across the
area today. Therefore have POPs held in the 50 to 60% range. As
Alberto moves north towards the Gulf Coast tonight, models show a
reduction in precip on the western side of the storm due to a combo
of dry air intrusion and loss of daytime heating. This should result
in quite a bit of gradient in rain chances from the western side of
the CWA to the east. This trend will continue as Alberto moves north
an makes landfall on Monday. The latest forecast track is even
further east than before as models have trended that way. Impacts
will follow, likely leaving the CWA in an area of minimal impacts.
The Tropical Storm Watch and Flash Flood Watch have both been
trimmed down to Mississippi Counties and its still a possibility for
those to be removed from the CWA all together in the near future.
Keeping them in place was more of a conservative decision in case
guidance starts trending back west.

Tuesday will be characterized by diurnal convection development
mainly across Mississippi and adjacent Louisiana parishes as
remnants of Alberto move north through Alabama.

.LONG TERM...
An upper level ridge centered in Mexico will be expanding north
across the Central Plains and towards the CWA Wednesday. This will
begin drying out western forecast zones while northeastern ones
still seeing some residual Alberto moisture. For the remainder of
the week into next weekend, temperatures will bounce back into the
lower to mid 90s with little convection as the high pressure aloft
brings increasing subsidence.

MEFFER
&&

.MARINE...
Winds will start to respond today to Alberto. Models are much more
agreeable with the eventual path of the storm but have shifted it
farther east and the official track has also been shifted as well.

Small craft advisory headlines have now been posted for waters west
of the tropical storm watch areas. There are a few marine areas that
will not meet wind speed criteria west of the Mississippi River but
they may meet total sea criteria. After Alberto`s departure,
conditions will slowly ease back to a more typical summer pattern.

.AVIATION...
Most if not all terminals will experience sh/ts again today but this
time most of the activity should occur during the morning and early
afternoon hours. There will finally be storm motion as well from
east to west and finally from northeast to southwest tonight into
Monday. VFR outside thunderstorms.

.DECISION SUPPORT...
DSS code: ORANGE.
Deployed: None.
Activation: Tropical desk;
6 hourly upper air special releases
Activities: Tropical cyclone
briefings; potential flood monitoring.


&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  86  69  85  69 /  60  20  50  30
BTR  88  71  88  72 /  60  20  50  30
ASD  86  71  86  72 /  60  30  60  40
MSY  86  74  87  75 /  60  30  60  40
GPT  83  72  86  74 /  50  50  80  40
PQL  83  71  84  71 /  50  60  90  40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Tropical Storm Watch for GMZ532-536-557-577.

MS...Tropical Storm Watch for MSZ080>082.

     Flash Flood Watch through Tuesday evening for MSZ082.

GM...Tropical Storm Watch for GMZ536-557-577.

&&

$$



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