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

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FXUS64 KLIX 222111
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
411 PM CDT Tue May 22 2018

.DISCUSSION...Isolated to scattered convection broke out early this
afternoon and additional activity continues to fire along outflow
boundaries but overall not seeing widespread storms. Again most
everyone is interested in the weak area of disturbed weather in the
western Caribbean and not too much has changed over the last 24
hours or the thinking going forward.

Tonight and tomorrow still looks like convection will be driven by
diurnal fluctuations. The ridge overhead remains in place but the
moisture plume will begin to shift more west as the ridge over the
western Atlantic nudges into FL. Expect storms to once again
initialize along the seabreeze/lakebreeze and anywhere boundaries
collide. As previous forecaster mentioned steering currents are
rather light so storm motion will be slow and storms will more so
propagate than move.

Come Thursday and through the weekend rain chances will increase.
obviously we are continuing to watch the tropical disturbance but
even if it stays east of the region, broad troughing aloft should be
more than enough to get showers and thunderstorms to develop
especially over the eastern half of the CWA. As mentioned earlier
the moisture surge should continue to nudge into the area and with
that a very moist airmass is expected to be in place with PWs near
2". Combine that with just a little bit of heating and troughing
aloft and we should have no problem getting at least scattered to
numerous showers and thunderstorms each day. With that we will
likely see bouts of moderate to heavy rain. At this time the
heaviest rain appears to be along the MS coast this weekend and
would not be surprised to see a few locations see over 6 inches of
rain by Monday.

The concern increases with respect to heavy rain if our western
Caribbean system is much closer or moves directly over the area. If
that occurs then the threat for heavy rain will expand to include
much of the area. In addition rain may not be completely driven by
diurnal fluctuations and we could see moderate to heavy rain
overnight. In addition this will be a slow moving system whether or
not it moves over our area so this will also increase the risk of
heavy rain.

The models continue to agree with a wet pattern being in place but
there is some pretty good disagreement in the track of the sfc low.
Hopefully in the next day or so we can get a better handle on things
and the models will come into better agreement so we can focus a
little more on the details. /CAB/

&&

.MARINE...One more day of generally light easterly to southeasterly
flow before winds start to slowly pick up. This will be in response
to the western Caribbean system. Winds will still be on the lighter
side Thursday probably still under 12 kts but by Friday winds could
increase to the 15-20 kt range and will begin to come out of the
east. Heading into the weekend there is still a lot of question marks
with respect to eventual track of any sfc low. Mariners should
remain attentive to subsequent forecasts for any changes that could
occur.

Showers and thunderstorms will be plentiful regardless of the
development of a subtropical or tropical system. At the very least
expect breezy conditions to eventually develop and of course with
any thunderstorm, gusty winds and waterspouts are possible. /CAB/

&&

.AVIATION...
Scattered showers and storms will continue through the afternoon and
early evening hours. Most of the convection is north of Lake
Pontchartrain this afternoon. Convection should diminish after
sunset. Expect MVFR to VFR conditions to prevail through the TAF
period. Expect VFR conditions for Wednesday as well and expect more
convection to be around as well. 13/MH

&&

.DECISION SUPPORT...

DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.

Decision Support Services (DSS) Code Legend
Green  = No weather impacts that require action.
Blue   = Long-fused watch, warning, or advisory in effect or
         high visibility event; Marginal risk severe or excessive rain.
Yellow = Heightened impacts with short-fused watch, warning or
         advisory issuances; radar support for Slight risk severe or
         excessive rain.
Orange = High Impacts; Enhanced risk severe; nearby tropical events;
         HazMat or other large episodes.
Red    = Full engagement for Moderate to high risk of severe and/or
         excessive rain, or direct tropical threats; Events of
         National Significance.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  69  87  70  87 /  30  50  30  70
BTR  71  90  71  89 /  30  50  30  60
ASD  70  88  72  87 /  20  50  30  60
MSY  74  89  74  87 /  20  30  40  70
GPT  73  87  74  86 /  30  50  40  60
PQL  70  88  71  85 /  30  50  40  60

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$


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