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

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FXUS64 KLIX 230056

Area Forecast Discussion
National Weather Service New Orleans LA
756 PM CDT Thu Mar 22 2018


Routine sounding terminated over Chandeleur Sound at a height of
107,500 feet or 20.4 miles above the surface.

Airmass remains dry with a precipitable water value of 0.53
inches. No significant pockets of moisture noted with an inversion
near 600 mb. Freezing level was at 10,900 feet, the -20C level at
22,900 feet.

Southwest winds at the surface were likely due to a lake breeze
from Lake Pontchartrain. Winds became northerly around 950 mb, and
then northwesterly at 700 mb, and remained northwesterly for the
remainder of the flight. The maximum wind of 78 knots was noted
just below 41,000 feet. 35


.PREV DISCUSSION... /issued 406 PM CDT Thu Mar 22 2018/

SHORT TERM (Tonight through Sunday)...

Pleasant weather conditions with generally clear to mostly
clear/sunny skies, low humidity and mild temperatures can be
expected through Friday as a large dome of surface high pressure
slides southeast across the lower Mississippi Valley, southeast
states and Gulf of Mexico under northwest flow aloft. Temperatures
rose as expected today with highs mostly in the upper 60s to
lower 70s. The mid/upper level trough axis will move east off the
Atlantic coast tonight and Friday while a ridge moves east across
the plains states. Both these features will continue moving
slowly east over the weekend with a flattening ridge axis
approaching then moving across the lower Mississippi Valley and
central Gulf coast region. Rising heights aloft combined with
southerly surface winds will bring substantially warmer
temperatures trending above the seasonal normals with lows rising
to the upper 50s to lower 60s Friday night, and highs are expected
to rise into the mid 70s over most areas inland from the cooler
coastal locations Friday and near 80 on Saturday. An increase in
clouds is expected to bring partly cloudy skies and higher
humidity levels by late Friday night into Saturday, but no rain is

LONG TERM (Monday through Thursday)...

A very active weather pattern, with a trough near the west coast
producing rounds of heavy precipitation to California in the short
term, will consolidate into a digging and strengthening upper low
over the desert southwest states early next week. The breadth of
this trough will result in an active and slow moving frontal
boundary over the southern plains to the mid Mississippi Valley
region in a wide belt of stronger southwest flow aloft. The threat
of heavy rainfall should move into the Ark-La-Tex region by late
Tuesday into Wednesday. For our forecast area, the focus for this
activity should remain to the northwest of the area through
Wednesday, so have only carried low rain chances for mainly
isolated showers Monday into Tuesday with slightly higher rain
chances inland on Wednesday. Looking beyond Wednesday, the ECMWF
model brings a now faster frontal boundary with showers and
thunderstorms into the forecast area late Wednesday night into
Thursday in a sheared pattern with a more open upper trough
hanging back over Arizona and New Mexico. The GFS consolidates
more shortwave energy with an ejecting trough across the southern
plains and lower Mississippi Valley region Thursday into Friday
with a slower moving front and more focus for heavy rain and
thunderstorms to the north of the forecast area. With model
inconsistency this far out, we will have to wait and see how this
pattern and weather threats unfold over the next several days.


VFR conditions will prevail through the TAF period. The next 15
hours will be quite uneventful. Southeasterly winds will increase
mid morning Friday. Expect gusty winds around 20 knots for most
terminals from 15z-21z Fri.



Surface high pressure currently centered north of the areas will
shift east on Friday. This will rotate winds from offshore to
southeast by around daybreak. The local pressure gradient will
tighten in response deepening leeside trough in the Central Plains.
Winds will respond to this and rise into the exercise caution
category in offshore waters. These 15 to 20 knots should persist
over the open Gulf waters through Saturday. Winds decrease on Sunday
before picking back up for early next week. A strong long-fetch
regime is expected to develop with onshore flow bringing near SCA
winds/seas and probably above normal tides.


DSS code: Blue.
Deployed: None.
Activation: None.
Activities: Monitoring river flooding

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.
Yellow = Heightened impacts with short-fused watch, warning or
         advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
         tropical events; HazMat or other large episodes.
Red    = Full engagement for Moderate risk of severe and/or direct
         tropical threats; Events of National Significance.


MCB  45  75  58  80 /   0   0   0  10
BTR  48  77  60  81 /   0   0   0  10
ASD  46  74  59  80 /   0   0   0   0
MSY  53  75  62  80 /   0   0   0   0
GPT  49  70  61  76 /   0   0   0   0
PQL  44  71  57  77 /   0   0   0   0



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