Flash Flood Warning 53, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
239 PM CDT Wed May 29 2024

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.SHORT TERM...
(This evening through Friday night)
Issued at 207 PM CDT Wed May 29 2024

A series of fast moving and weak southern stream shortwave troughs
embedded within a largely zonal flow regime aloft will slide
through the Lower Mississippi Valley over the course of the short
term period. As these shortwave features move through the area,
the increased forcing aloft will support the development of
convective activity each afternoon. The convection is expected to
initially develop over east Texas and western Louisiana in the
late morning and early afternoon hours and then follow the theta e
axis to the east or southeast into the forecast area by the late
afternoon and early evening hours each day. Given this risk, have
included chance PoP values of 30 to 40 percent in the forecast
generally between 21z and 03z on Thursday and Friday. Fortunately,
the risk of severe storms remains low with the convection due to a
lack of substantial wind shear. However, a few wet microbursts
producing locally strong wind gusts could occur if drier air in
the mid-levels becomes entrained into the updraft of any deeper
convective cells. Overall, the convective threat will be highly
diurnal with mainly dry conditions expected from late evening
through early afternoon each day. Temperatures will be near to
slightly above average through the period with highs in the upper
80s and lower 90s and lows ranging from the upper 60s to the mid
70s. Overall, have stuck with the NBM deterministic output for
temperatures. We are very much in an early Summer regime at this
point.

&&

.LONG TERM...
(Saturday through Tuesday night)
Issued at 207 PM CDT Wed May 29 2024

The area will continue to have daily slight chances of showers and
storms as some weak disturbances ride to our north as an upper level
ridge builds up from Mexico. So overall we are entering into
summertime pattern with daily diurnally driven convection. Overall
not expecting any severe thunderstorms but Friday is outlooked as
marginal by SPC. There is plenty of CAPE and moisture for storms to
tap into , but failure modes could be weak shear and lapse rates.

Temperatures will have a slow warming trend with highs in the low
90s. There will still be ample moisture being pumped into the area
thanks to onshore flow, so we could see heat indices tickle around
100 F. As of right now it's not looking like the heat we had last
weekend/early this week. -BL

&&

.AVIATION...
(18Z TAFS)
Issued at 207 PM CDT Wed May 29 2024

The primary forecast concern through the evening hours will be
the potential for convective impacts at MCB. A complex of showers
and thunderstorms is currently moving through central Louisiana,
and if this area of storms holds together could impact MCB between
22z and 02z. Have included prevailing SHRA and TEMPO group with
thunderstorms for this time period. Elsewhere, the risk of
convective development is too low to include in the forecast at
this time. Going into tomorrow morning, most areas will remain
VFR, but if evening rains do impact MCB, a period of IFR ceilings
and visibilities could develop between 10z and 13z due to the wet
soils. By 14z, all of the terminals will see VFR conditions return
as the boundary layer fully mixes out.

&&

.MARINE...
Issued at 207 PM CDT Wed May 29 2024

A Summer regime will be in full effect through early next week
across the coastal waters. Prevailing south and southeast winds of
10 to 15 knots and seas of 1 to 3 feet can be expected through the
entire period as a broad surface high pressure systems remains
centered to the east of the region. There will be a threat of
some thunderstorm activity moving offshore from land each
afternoon and evening, and these storms could produce gusty winds
and lightning, but the impacts will be short- lived.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  66  88  67  88 /  40  40  20  30
BTR  70  89  71  89 /  30  40  20  40
ASD  70  90  71  89 /  30  20  10  20
MSY  75  89  75  88 /  20  20  10  30
GPT  73  89  74  87 /  20  10  10  20
PQL  71  89  71  88 /  20  10  10  20

&&

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

SHORT TERM...PG
LONG TERM....BL
AVIATION...PG
MARINE...PG