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

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672
FXUS64 KLIX 191557
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1057 AM CDT Tue Jun 19 2018

.UPDATE...

Surface observations show temperatures have risen into the low to
mid 80s across the region. Radar and satellite show showers and
thunderstorms beginning to develop and this trend is expected to
continue through the afternoon. Overall, the inherited forecast
remains on track with this update mainly consisting of
incorporating the latest surface observations. The main change was
to increase winds over the western marine zones where winds so far
have been under-forecast and the surface pressure gradient
resulting in these stronger winds is expected to persist through
this evening. 26

&&

.PREV DISCUSSION... /issued 353 AM CDT Tue Jun 19 2018/

SHORT TERM...
A tropical wave meandering across southeast Texas extends well
across Louisiana into Mississippi. The upper air sounding from 00Z
yesterday showed just how much moisture has spread into the area. PW
was over 2 inches which is above the 90th percentile for this time
of year. Model soundings show that number creeping up throughout the
day. With so much moisture in place, should be easy for numerous
showers and thunderstorms again today. Therefore, mirrored the MAV
for POPS today as opposed to the conservative blended guidance. The
main potential impact today will be locally heavy rainfall due to
such efficient rain processes expected.

On Wednesday, an upper ridge will spread south and west across then
Gulf of Mexico from Florida westward. Although subsidence will
moving in from the Gulf, still will have enough moisture in place
for rain chances to be in the 40 to 50% range. The only exception is
far easter portions of the CWA where column moisture in lower and
subsidence is stronger.

An upper low will be tracking into the Central Plains Wednesday and
Thursday. This will cause the ridge over the Gulf to retreat
slightly. A gradient in convective coverage will likely exist with
highest POPS in northern forecast zones and lowest along the
coastline.

LONG TERM...
The aforementioned upper low will lift northeast ending this week,
thus allowing the ridge over the Gulf to spread north over the
region this weekend. Subsequently, rain chances will drop quite a
bit and temps should be on the rise. Kept previous POPS of 20% and
slightly increased high temps into the lower 90s.

AVIATION...
Another round of scattered sh/ts are expected with more activity to
the west than those terminals to the east. A few sites mainly west
will have ceilings around BKN015 temporarily as most should remain
well in VFR. Some ceilings in the BKN060 can be expected for this
afternoon for a short time as well. Not a lot of difference between
this morning and tonight expected.d low pressure system over Texas.

MARINE...
A fairly tight pressure gradient remains in place over the open Gulf
waters west of the Mississippi River this morning.  Onshore flow of
15 to 20 knots and seas of 4 to 6 feet will persist over these
western waters through this evening. The pressure gradient will
gradually begin to ease tonight and Wednesday as the low over
Texas weakens and a broad ridge of high pressure strengthens over
the eastern Gulf of Mexico. Winds and seas should drop to around
10 knots or less, and seas should fall to 3 feet or less for the
latter part of the week and the upcoming weekend.

DECISION SUPPORT...

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

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  87  73  89  73 /  60  20  50  20
BTR  85  75  89  74 /  70  20  50  20
ASD  88  76  90  75 /  50  20  20  20
MSY  88  77  90  77 /  50  20  30  10
GPT  89  77  89  77 /  40  10  20  10
PQL  91  75  90  75 /  30  10  20  10

&&

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

$$



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