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

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000
FXUS64 KLIX 220147
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
747 PM CST Tue Feb 21 2017

.SOUNDING DISCUSSION...
There were not any problems with the upper air release this evening.
The 00Z sounding indicated a a slightly unstable profile that had
become drier since this morning. In particular, drier air was
more prominent in the mid and upper levels. The total precipitable
water was down to 1.03 inch. A light southwest flow near the
surface was northwest to west northwest throughout much of the
remainder of the column. 11

&&

.PREV DISCUSSION... /issued 308 PM CST Tue Feb 21 2017/

SHORT TERM...
Only real weather impact in the short term will be some showers
as the upper low meanders through the area this evening. Can`t
entirely rule out a couple lightning strikes, but the chance of
thunder is low enough to preclude from putting it in the actual
forecast. Lows tonight should be about 5 to 10 degrees cooler
than last night, bottoming out in the upper 50s for southern areas
and lower 50s for northern areas. Some patchy fog could develop
late.

Tomorrows afternoon temperatures should top out in the mid 70s and
dewpoints in the 50s should keep things pleasant. Clouds will
gradually clear from west to east through the morning hours giving
way to mostly sunny skies by the mid afternoon. Another cool night
on tap for Wednesday night as mostly clear skies and dewpoints in
the 50s allow for fairly efficient radiative cooling. Expect lows
in the 50s once again...which is still several degrees above
normal for this time of year.

LONG TERM...
Bottom line up front - overall sunny skies and dry conditions
ideal for outdoor festivities are expected. Thursday and Friday
will arrive very warm with afternoon temperatures in the upper 70s
to near 80. The central Gulf Coast will be in southerly flow as a
strong cyclone passes well to the north across the central US. A
cold front crosses the area into the Gulf Friday night and early
Saturday morning. The passage is expected to be nearly dry with
just a brief line of showers possible. The main change Saturday
will be temperatures 10 to 15 degrees cooler and breezy northerly
winds. High pressure at the surface builds in Saturday and Sunday.
Monday will be warmer as southerly flow returns from the Gulf. At
this time Tuesday looks to have a slight chance for spot showers
in the moist onshore flow with continued warm temperatures.

AVIATION...
Main precipitation shield has moved east of all terminals with
ceilings currently ranging from MVFR to VFR. Scattered convection
currently associated with upper low sliding just south of KBTR and
should be near KHUM around 21z. Biggest question is whether loss of
heating will cause dissipation of convection, or whether it will
continue eastward. Have already dropped mention of convection from
KMCB and may be able to drop it from remaining terminals that are
north of Interstate 10-12 corridors within the next hour or so.

Secondary question will be potential for fog development late
tonight. Dew points across western half of the area are in the low
50s, which is close to forecast lows tonight. Certainly some threat
of a fog event, but confidence not high enough to carry as
prevailing in forecast at this time. Do have mention of MVFR to
IFR conditions in most terminals, but will have to reassess this
evening. In any case, conditions will improve to VFR by mid-
morning Wednesday.

MARINE...
Upper low centered near Natchez at mid-afternoon will continue to
move southeastward toward south Florida over the next 48 hours.
Outside of overnight convection tonight, only a couple of areas of
concern. Could be an increase in winds over the eastern outer waters
late Wednesday as pressure gradient tightens somewhat with the
surface low. Second concern will be the passage of a stronger cold
front Friday night into Saturday. Likely to need Small Craft
Advisories on Saturday for at least the open waters. Headlines
likely to be necessary into Sunday before conditions relax.

DECISION SUPPORT...
DSS code: Green.
Deployed: None.
Activation: None.
Activities: Monitoring convective trends.

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.

DSS code: Green.
Deployed: None.
Activation: None.
Activities: Monitoring convective trends.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  52  75  52  81 /  20  10   0   0
BTR  56  74  54  81 /  20  10   0   0
ASD  53  75  54  79 /  30  10   0   0
MSY  57  72  56  78 /  40  10   0   0
GPT  56  72  57  75 /  30  10   0   0
PQL  53  74  55  77 /  30  10   0   0

&&

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

$$



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