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

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043
FXUS64 KLIX 211739
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1139 AM CST Tue Feb 21 2017

.AVIATION...

Main precipitation shield has moved east of all terminals with
ceilings currently ranging from MVFR to VFR. Now seeing scattered
convection associated with upper low extending from near KBTR to
KLCH. Will carry VCTS in terminals for at least part of the
afternoon with occasional MVFR ceilings. Will handle any direct
impacts on terminals with amendments. Can`t rule out a couple
storms producing small hail, but threat not large enough to carry
in terminals. With loss of heating, expect most, but not all,
convection to dissipate around 00z. VFR conditions expected for
most of the evening and early overnight hours, but could see MVFR
to IFR conditions for a few hours around sunrise Wednesday. By 15
or 16z Wednesday, anticipate all terminals becoming VFR. 35

&&

.PREV DISCUSSION... /issued 821 AM CST Tue Feb 21 2017/

..SOUNDING DISCUSSION...
As can be seen on water vapor imagery the center of the upper low
is just to the west over southwest LA this morning. Winds are
southwest above light and variable at the sfc and reach 50 kts by
860 mb. The wind backs to the south through mid levels before
becoming more westerly at the tropopause. The profile is near
saturated with PW is at 1.5 inches, which is near the max for this
time of year. Lapse rates will steepen a bit today as the cold
pool center of the upper low passes overhead. This will likely
provide just enough instability for scattered storms, some of
which are over the LA/TX border at the moment.

Krautmann

PREV DISCUSSION... /issued 658 AM CST Tue Feb 21 2017/

UPDATE...

Fairly significant update to the current forecast to include
scattered thunderstorms with the potential for small hail as the
cold core upper low begins to rotate through the area after noon
today. Severe weather with these thunderstorms is not expected at
this time but will be watched as they move east. Will only set
this during the afternoon hours for now.

PREV DISCUSSION... /issued 321 AM CST Tue Feb 21 2017/

SHORT TERM...
Strong showers moving through the area this morning. Most winds
have been gusting to 25kt while several have been 36kt or better.
One of these observations reached 44kt(50mph). No lightning with
any of this activity this morning so far but conditions are such
that an isolated lightning strike is possible at least over the
eastern most portion of the area. The initial line of showers will
move east of Mississippi this morning while the secondary much
slower line will take its time crossing the area. So far this
morning rainfall amounts are in line with fcast of 1-2". Most
areas will receive at least moderate rainfall over a 6hr period.
But since this amount of rain should be spread over the entire
timeframe, only ponding in the usual places is expected.

We will remain cloudy with light rain or even drizzle at times
through Wednesday on the back side of this system. The next cold
front will clean all this out and cool things down starting Friday
night. There is enough forcing with this boundary to cause at
least a 20% chance of rain right along the boundary but no
thunderstorms expected. The next system looks to move close but
may stall before reaching the area next Tuesday.

AVIATION...

A band of precipitation moving across the terminals will continue to
keep IFR and MVFR conditions in place through the morning hours.
Ceilings could fall to as low as 300 feet at times through 12z.
Visibilities should generally be in the 3 to 5 mile range when bands
of moderate rain move through.  Mesoscale model guidance suggests
the band of precipitation should move out of the area by 20z
resulting in improved conditions into VFR range for the late
afternoon and evening hours.  Conditions look favorable for some
lower visibilities in the IFR range to affect all of the terminals
tomorrow morning.  32

MARINE...

A general west to northwest flow regime will take hold of the
coastal waters today and persist through Wednesday.  This northwest
flow pattern should result in continued exercise caution conditions
over portions of the open Gulf waters with lighter winds of 10 to 15
knots in the sounds and lakes.  Winds should quickly veer back to
the southeast Thursday into Thursday as a ridge of high pressure
strengthens to the east of the area.  This southerly flow pattern
should persist through Friday with winds of 10 knots or less
expected.   Seas should respond to these lighter winds and drop to 3
feet or less for the latter part of the workweek.  A strong cold
front is expected to then sweep through the coastal waters Friday
night, and have winds shifting to the northwest and increasing Small
Craft Advisory range for Saturday.  The wind field should ease
slightly Saturday night and Sunday, but continued exercise caution
winds of 15 to 20 knots and seas of 3 to 6 feet are currently
expected.  32

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  71  53  76  52 /  60  30  20   0
BTR  72  56  74  54 /  40  30  20   0
ASD  71  54  76  54 /  70  30  20   0
MSY  72  57  72  57 /  60  30  20   0
GPT  68  55  72  57 /  90  30  20   0
PQL  69  53  74  55 /  90  30  20   0

&&

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

$$



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