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

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000
FXUS64 KLIX 170155
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
755 PM CST Sun Feb 16 2020

.UPDATE...Sending out a quick update to add a dense fog advisory
for the coastal areas and the marine zones. Not as confident as
dense fog will be as widespread but there will likely be patchy to
areas of dense fog overnight and around rush hour traffic
tomorrow. To get a heads up on the possibility of fog issues we
have decided to go ahead and issue the advisories. In addition the
advisory may need to expand farther inland. /CAB/

&&

.PREV DISCUSSION... /issued 422 PM CST Sun Feb 16 2020/

SYNOPSIS...
Surface analysis showed a low over north central Gulf with
frontal boundary from northeast gulf to the low to northwest gulf.
Surface dewpoint values were from the mid 50s across the central
Mississippi to lower 60s to the Louisiana coast. In addition, a
1004mb low over eastern New Mexico. Upper air analysis showed a
positively tilted short wave over central Mississippi to southeast
Texas.

DISCUSSION...
Although the surface low and short wave will continue to push east
through tonight and Monday, residual low level moisture will
remain in place tonight. Fog formation is likely over land areas
tonight. Another shortwave in a very active southern stream will
move across the area Monday afternoon and night, with another
round of showers and a few embedded storms. Elevated mean relative
humidity values will increase from the southwest as the warm front
moves north across the forecast area on Monday. Surface low
currently over northeast New Mexico will track east and northeast
Monday and Tuesday. After the low passes east, the associated cold
frontal system will drop south into the area Tuesday afternoon
and evening, with more showers and a few storms. Any surface
heating will provide instability in this moisture for showers and
few storms especially across the north half of the forecast area
late Monday through Wednesday and possibly Thursday. Not
expecting any any severe weather or flash flooding issues.

Frontal passage will occur on Wednesday but southwest flow aloft
will maintain a threat of rain through Thursday. Short wave will
dive southeast across mid Mississippi Valley Friday and southeast
coast Saturday. This feature will yield a northwest flow over the
forecast area Friday and Saturday. GFS and Euro show a deep low
over southwest CONUS, but Euro lift this low on a more southerly
track across the Arklatex next Sunday while GFS GFS is farther
north. Both show a threat of storms across the region late Sunday
through Tuesday of next week. Later packages will have examine.

AVIATION...

Ceiling of 800 to 2000 feet will persist at all taf sites this
afternoon and will lower 300 to 600 feet later this evening and
overnight. Fog will yield some restrictions with values down to
1/2sm at times between 11z and 15z Monday morning. 18

MARINE...

Variable winds are expected behind the low tonight. Onshore flow
will become established Monday through late Tuesday. Cold frontal
passage is expected Wednesday with a stronger frontal passage
Thursday afternoon. Small Craft Advisory situation is likely for
most of the waters Thursday into Friday. As mentioned above,
there will be a threat of sea fog tonight, and potentially for the
following 2 nights. Will maintain fog nearshore it for tonight
and Monday night.

DECISION SUPPORT...
DSS code: Blue.
Deployed: None.
Activation: None.
Activities: River flooding on Mississippi and Pearl;
            Ongoing NASA Stennis support;
            Parade safety briefings.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  52  69  62  73 /  10  30  70  80
BTR  54  71  63  76 /  10  30  40  70
ASD  51  70  61  76 /  10  30  40  70
MSY  57  72  65  77 /  10  30  40  50
GPT  54  67  61  71 /  10  30  40  60
PQL  50  70  61  73 /  20  30  40  60

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Dense Fog Advisory from midnight tonight to 8 AM CST Monday for
     LAZ040-049-050-056>070-072.

GM...Dense Fog Advisory until 8 AM CST Monday for GMZ530-532-534-536-
     538-550-552-555-557.

MS...Dense Fog Advisory from midnight tonight to 8 AM CST Monday for
     MSZ080>082.

GM...Dense Fog Advisory until 8 AM CST Monday for GMZ532-534-536-538-
     550-552-555-557.

&&

$$


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