Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
FXUS64 KLIX 231313
Area Forecast Discussion
National Weather Service New Orleans LA
813 AM CDT SAT JUL 23 2016
The sounding this morning depicts a bit more dry air at mid levels
compared to yesterday... though low levels are near saturated and
overall PW is still at 2.0 inches. That layer of drier air could
support strong microbursts within some storms. 500 mb height of
592 dm is down from the past couple days as the center of the
upper high is further to the northwest. There is plenty of
instability for storms today with mixed layer CAPE at 1900 J/KG
and most unstable over 3000 J/KG. Warm cloud dept is near 15500 ft
so storms will be efficient rain makers and like yesterday slow
movers may cause localized flooding problems. Winds are light and
variable to 850 mb then northeast through the rest of the profile.
.PREV DISCUSSION... /issued 352 AM CDT SAT JUL 23 2016/
Looks to be wet through at least Thursday. Higher than normal rain
chances each day will be helped out by a successive parade of
TUTT(Tropical Upper Tropospheric Trough) lows. We will continue to
experience disturbances rotating around the upper/mid level high
to our northwest through Sunday. After that, the upper lows will
start to advance westward through the gulf causing a deep layer of
tropical moisture to move into the area. Basically, the pattern
changes from more continental over the weekend to a maritime
regime by the start of the work week. Not that anyone will notice
by sh/ts chances each day. The thing that may be noticed will be
a slight lowering of daytime highs starting Monday.
The first TUTT low will break away from the upper trough off the
east coast this weekend and move through the gulf Monday and
Tuesday delivering a deep moist column which will make it quite
easy to get sh/ts going. As convective temps fall back several
degrees, we will see two crops of sh/ts activity develop. The
first will be maritime nocturnal which we are finding along the
coast now, but by the start of the week they will begin their
march inland. And the second batch will develop over land during
the day. These should start to tower fairly early through much of
The second TUTT low is currently located just north of Puerto
Rico. This low will get a rapid shove westward by Monday causing
it to move through the gulf Wednesday and Thursday. This may
linger into Friday but a short term environmental change looks to
occur by late Friday into the weekend.
A dry surge should be making its way to the area from the SE for
next weekend ahead of the next TUTT low which will break away from
the upper trough that is currently digging into the NE. This low
will rapidly traverse the eastern periphery of the Atlantic ridge
and finally move west visiting the gulf by the start of the next
new week. Problem with drying out over next weekend will be the
Some patchy fog has been observed at a few terminals. This should
mix out shortly after sunrise. Otherwise expect VFR conditions to
prevail before convection is expected to get going. There is some
convection currently in the coastal waters and we expect convection
to get going later on this morning and lasting into the afternoon
and evening hours. Have added VCTS to most terminals. These showers
and storms could briefly drop conditions to IFR if a terminal is
directly effected by a storm. Otherwise expect VFR conditions to
High pressure remains the main feature driving the weather over the
period. Main concern will continue to be lines or clusters of
thunderstorms that develop. More active thunderstorms are expected
the next couple late nights and early mornings. A weak upper low
will move into the coastal waters next week and will only enhance
rain chances going into early next week. 13/MH
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 92 75 91 74 / 40 20 60 20
BTR 93 77 92 76 / 40 20 60 20
ASD 91 78 90 77 / 40 20 60 30
MSY 91 78 91 78 / 40 20 60 30
GPT 90 78 89 78 / 40 20 60 30
PQL 89 76 89 77 / 30 20 50 30