Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
FXUS64 KLIX 252024
Area Forecast Discussion
National Weather Service New Orleans LA
324 PM CDT MON JUL 25 2016
Weak upper low over the eastern Gulf of Mexico with an inverted
surface trof off the Louisiana coast. The most widespread
convection has actually been over the Lake Charles CWA and coastal
waters today, but scattered convection has developed over the
local area in the past 90 minutes, moving westward. Temperatures
have probably topped out for the day in the upper 80s to lower
90s. Airmass remains very humid with dew points in the mid and
upper 70s, producing heat index values between 100 to 105 outside
of rain areas.
Upper low will continue to move westward across the Gulf of Mexico
over the next 48 hours. Atypical for marine convection to persist
all day in July, but it has continued, primarily over the Lake
Charles and Houston land/marine areas. Have noted falling
pressures during the day locally, and will need to keep an eye on
things over the Gulf.
Airmass will remain extremely moist with precipitable water
values between 2.1 and 2.3 inches at New Orleans. With convective
temperatures in the mid to upper 80s, this will allow the
development of scattered to numerous thunderstorms. This will be
primarily during the late morning and afternoon hours for much of
the land portion of the CWA on Tuesday and Wednesday. Marine areas
will be somewhat more favored for convection overnight. Highest
rain chances will be across southern portions of the
area...slightly lower across southwest Mississippi. Precipitable
water values drop slightly on Thursday, so there might be a little
less areal coverage of convection.
As noted, convective temperatures are expected to be in the mid
to upper 80s Tuesday and Wednesday, so most areas should not get
past 90 for highs both days. Could see readings a degree or two
higher on Thursday with slightly less convection. Overnight lows
should remain in the mid to upper 70s through the period. 35
Local area remains in the weakness between the Bermuda ridge and
the Four Corners ridge. Airmass will be slightly drier than early
in the week and will go with slightly lower rain chances and
slightly higher temperatures over the weekend. Still not much
higher than lower 90s for highs, but with the humidity, we aren`t
going to be able to tell much difference. 35
Convection scattered across the forecast area this afternoon will
have the potential to affect any of the TAF sites until around
sunset. However, any restrictions to visibility or ceilings as a
result of the convection is expected to rather brief. Scattered to
numerous showers and thunderstorms are expected again on Tuesday,
primarily from late morning through the afternoon. Otherwise, VFR
category conditions will generally prevail at the terminals through
the TAF forecast period outside any areas of convection. 11
A weak area of low pressure off of the southeast/south central
Louisiana coast and an inverted trough extending across the coastal
waters along with a weakness aloft will result in enhanced shower
and thunderstorm coverage over the marine area over the next couple
of days. The trough will cause winds to increase to 15 knots mainly
over the open Gulf waters Tuesday and east of the river Tuesday
night into Wednesday. Gusty winds may accompany any of the
thunderstorms. Thereafter, mainly light south to southeast
flow will prevail along with scattered convection. 11
DSS code: Green.
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.
Yellow = Heightened impacts with short-fused watch, warning
or advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
tropical events; HazMat or other large episodes.
Red = Full engagement for Moderate risk of severe and/or
direct tropical threats; Events of National Significance.
.PRELIMINARY POINT TEMPS/POPS...
MCB 74 90 73 89 / 20 60 40 60
BTR 75 90 75 88 / 30 70 50 60
ASD 76 89 75 88 / 30 70 50 60
MSY 80 90 78 88 / 30 70 60 60
GPT 77 87 77 88 / 30 70 60 60
PQL 76 88 75 88 / 30 70 60 60