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

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000
FXUS64 KLIX 211013
AFDLIX

AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
413 AM CST Wed Feb 21 2018

.SHORT TERM...
An upper level ridge is currently centered north of the Bahamas and
will remain there through most of this week. The west side of this
high pressure extends into the Bay of Campeche. This extent of
coverage will change throughout the week based upon intrusion of an
upper trough to the northwest. The main trough axis is still west of
the Rockie Mountains but a weak shortwave tracking through the
trough will bring a cold front into northern Louisiana today and
stall it there due to the weakness and northerly track of the
shortwave. Rain chances will increase quite a bit today. There`s
quite a bit of spread between MAV and MET guidance. Relatively
higher coverage the last 2 days suggests it makes more sense to lean
on wetter guidance. Thus there should be a gradient in pops ranging
from near 70% in far northwestern zones to 30% along the LA coast.
It appears most of the convection will not develop until later in
the day but scattered showers are certainly possible this morning.

A slight retreat of the stalled front to north is likely on Thursday
as the shortwave races northeast and the ridge builds in from the
south. Rain chances should fall back into the 10-40% range as this
takes place. It will be a short reprieve from higher coverage as
another weak shortwave enhances shower and thunderstorm coverage
again on Friday. 80+ degree high temps will persist through this
part of the forecast period as ridge keeps 500mb heights high.
Blended model guidance continues to be too cold for max temp
forecast, so used mav/mex.

.LONG TERM...
The main upper trough axis west of the Rockies will finally lift
northeast and race across the midsection of the country this
weekend. This will send a front through the forecast area early
Sunday morning. Models are now showing it stalling across the CWA
due to the trough lifting north quicker and therefore not providing
enough push to bring the front offshore. A line of showers and
thunderstorms will likely accompany this boundary as it moves in.
The ridge that was north of the Bahamas will then shift west towards
the southern Gulf of Mexico. This will put the CWA in conducive area
for persistent shower and thunderstorm development early next week.
Thus it now appears that higher rain chances beginning Sunday will
carry on into early next week.

MEFFER
&&

.AVIATION...
Ceilings will be mainly at BKN030-040 with some SCT as well. TEMPO
ceilings this morning at BKN003-006 for those terminals down wind of
cooler water bodies and the Mississippi River. Vis restrictions
could be as low as 1sm for these terminals as well. Any low ceilings
will break up by mid morning. Tonight may have a bit more FG for
those near the cooler water bodies as ceilings may fall to OVC001
and IFR or worse vis at times since wind speeds may be a little
lower tonight.


&&

.MARINE...
Winds will remain in the 15-20 kt range for most coastal waters and
this should keep fog from forming and instead promote a low stratus
deck from time to time along with some shower activity. A cold front
will move toward the coast and stall well north of the coastal
waters today before moving back to the northwest, then stalling once
again over the central plains states. This will simply help maintain
the onshore flow through the remainder of the week. The front will
finally push into the coastal waters by late Sunday and stall
through Monday morning before moving again.

&&

.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.
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.


&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  82  68  83  66 /  60  40  30  20
BTR  84  69  85  66 /  50  30  40  20
ASD  84  69  84  65 /  50  20  20  20
MSY  84  69  84  67 /  30  10  10  20
GPT  78  67  80  64 /  40  10  10  10
PQL  81  67  82  61 /  40  10  10  10

&&

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

$$



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