Flash Flood Warning 18, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
311 PM CDT Sat Jul 4 2020

.SHORT TERM...
Tonight through Monday...convection from this afternoon will
continue into the evening...models hint at some westward and
southerly propagation along the outflows into the New Orleans
Metro and towards Baton Rouge by late afternoon/early evening.
After loss of heating as we approach sunset would likely see the
convection start to wane across the area. Inside any thunderstorms
may be very heavy rainfall with slow moving storms and PWATS at or
just over 2 inches...rainfall rates of 4-5inches per hour are
being seen at this time along with 25-30kt wind gusts.

Frontal boundary and weak low will remain near the region through
the short term period with mainly more diurnally driven convection
each day...some lingering showers and isolated thunderstorms
possible overnight but smaller chances for sure..may have overdone
chances for rainfall overnight. Evening crew can follow radar and
mesoanalysis trends to adjust if so tonight...possible tomorrow
night and Monday night as well as no real indication of
significant driver of the convection but daytime heating even with
the boundary in place. Overall, high forecast certainty for storms
during the afternoon and evening...much lesser certainty for late
night into early morning. Afternoon high temps a bit lower than
seasonal due to the cloud cover, overnight lows may be a bit
higher because of the same cloud cover from daytime storms. ABS

.LONG TERM...
Tuesday through Saturday...Frontal boundary remains to start the
long term portion of the forecast before some indication that
upper level ridging to the west and south pushes the boundary and
the weak low out of the area mid week into Thursday. Mostly
diurnally driven storms and showers with locally heavy rainfall
Tuesday and Wednesday. Drying out Thursday into the weekend for
the most part...some uncertainty exists exactly how the ridge sets
up and that can have a huge role in precip chances late next week
into the weekend. If the ridge is slightly further west and/or
north then we could see "ring of fire" storm development as
easterly flow pushes moist gulf air into the region...if the ridge
moves a bit further east then it could stifle any chance for
storms and temps could become quite hot into the middle 90s at
least by Friday or Saturday and into the weekend. Alot at play for
the far end of the extended forecast. ABS

&&

.AVIATION...
18Z TAFS... VFR conditions will dominate the period...but with
convection developing this afternoon and continuing into the
evening will look for possible tempo periods of MVFR and IFR at
most sites. Have used VCTS with CB for now to show this potential
and will watch radar trends for updates to TAFs across the area.
Light winds will continue through the period outside of the
storms...with the possibility of minor drops in visibility to
5-6sm in the early morning hours. Didn't fully embrace that in
TAFs as some of that I believe is predicated on how much rainfall
occurs today/tonight and if clearing of the skies can occur. ABS

&&

.MARINE...

Winds will be light (<15 knots) and westerly through Monday
morning. Monday evening through Friday morning, winds will be
light (<15 knots) and southwesterly to southerly. Friday evening
through Saturday, winds will be light (<15 knots) and westerly. Wave
heights will correspond with the wind speeds. MSW

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  73  88  74  85 /  60  80  60  90
BTR  74  88  74  85 /  60  70  60  90
ASD  72  89  74  87 /  60  80  70  90
MSY  75  87  76  86 /  60  70  70  80
GPT  75  86  76  85 /  60  80  70  90
PQL  72  89  73  87 /  60  80  70  90

&&

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