Flash Flood Warning 51, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
418 AM CDT Wed Aug 3 2022

.SHORT TERM (Today through Friday)...

Main concern over the next couple of hours is fog, which has set
in fairly thick over portions of the area. Not expecting the fog
to become widespread in most areas but went ahead and issued a
dense fog advisory for a few parishes and counties where the
highest likelihood exists. These areas could see periods of dense
fog through the rest of the overnight hours with the fog burning
off fairly quickly after sunrise.

Once the fog burns off, concerns will quickly shift to the
possibility of heavy rainfall once again today. Many parts of the
area have seen considerable rainfall over the past several days
with a few locations having had measurable rainfall for quite an
extended period. While the areas that are saturated are not
widespread, some areas have seen rainfall amounts well above
normal over the last week or so. Due to this, the entire area is
outlooked for a marginal risk of excessive rainfall today with a
narrow area from Baton Rouge to New Orleans in a slight risk.
Rainfall today is expected to be widespread in nature once again
and if it becomes organized in any way, could lead to flooding
issues as rainfall rates of 2-3 inches per hour are likely. A few
of the more efficent storms could produce hourly rainfall rates
closer to 5 inches per hour.

While a few of the storms today could once again become strong,
they are likely to remain generally below severe limits in regards
to wind. The primary concern is surely the possibility of
flooding.

More of the same is expected tomorrow and Friday with high rain
chances and the possibility the showers and thunderstorms that
develop could be efficent rain producers.

.LONG TERM (Saturday and beyond)...

No real changes in the large scale pattern noted for the weekend
and the beginning of next week. Daily rounds of diurnal convection
is expected to continue, with temperatures not straying much from
seasonal norms. Isolated very heavy rain will continue to be
possible.

&&

.AVIATION...

The primary concern through around 14-15Z will the development of
low stratus and fog at a few of the terminals as the combination
of light boundary layer winds below 10 knots, high relative
humidity and soil moisture content, and already cool conditions
allows for an inversion to strengthen through the night. Fog and
low stratus is already evident along the Pearl River Valley and in
the Mississippi Pine Belt. These IFR and lower conditions should
develop at MCB around 08Z and continue through 14Z. At BTR, HDC,
and ASD, low stratus is expected to be more prevalent, and have
TEMPO groups to reflect the risk between 10Z and 13Z. After 15Z,
enough mixing will be in place to clear the fog and low stratus.
However, TEMPO groups around 18Z to 22Z reflect the risk of low
visibilities and gusty winds accompanying any convective activity
that passes over the terminals during that timeframe. The risk of
storms is high tomorrow, so confidence was substantial enough to
include IFR visibilities in the TEMPO groups. PG

&&

.MARINE...

Light onshore flow will continue through the week as weak ridging
remains in place across the northern Gulf of Mexico. The main
issue will be increased winds and seas near any showers and
thunderstorms that develop, along with an increased risk of
waterspouts near and in association with those storms.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  87  69  87  70 /  80  30  80  10
BTR  89  72  89  72 /  90  30  90  20
ASD  89  72  89  73 /  90  40  90  20
MSY  87  75  87  76 /  90  40  90  20
GPT  87  74  88  75 /  90  50  80  20
PQL  87  73  89  74 /  90  60  80  20

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Dense Fog Advisory until 10 AM CDT this morning for LAZ039-071.

GM...None.
MS...Dense Fog Advisory until 10 AM CDT this morning for MSZ070-071-
     077.

GM...None.
&&