Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
FXUS64 KLIX 280854
Area Forecast Discussion
National Weather Service New Orleans LA
354 AM CDT THU JUL 28 2016
The loss of deep tropical moisture over the area as indicated by
precipitable water values below 2 inches and lower mixing ratios
around 13 g/kg will result in less overall convective coverage for
today. This drop in moisture is related to some weak ridging and
subsidence developing in the upper levels this morning. Overall,
expect to see more widely scattered convection form during peak
heating hours, and have placed 20 to 40 percent in the forecast.
The convection should dissipate shortly after sunset, and have POP
of around 10 percent for the overnight hours. Temperatures will be
very close to seasonal norms in the lower 90s during the day and
the middle 70s overnight.
Any weak ridging in place will be gone by tomorrow morning as a
broad upper level trough develops across the Lower Mississippi
Valley. This trough axis should linger over the area through the
remainder of the weekend and provide some additional upper level
lift to the region. As a result, there will be little in the way
of convective inhibition through the entire weekend. No
significant increase in moisture content is expected through the
weekend with PW values generally remaining between 1.75 and 2
inches. Overall, expect to see convective coverage close to what
is typically expected for the Summer months with a 40 to 50
percent chance of convection from late morning through the
afternoon hours. Most of the convection should dissipate after
sunset with only offshore convection peaking around daybreak.
Temperatures will be near average through the weekend.
The overall upper level pattern is expected shift slightly with
ridging in the plains states increasing, and the ridge over the
eastern Gulf and Florida easing. However, this pattern still has a
broad area of lower pressure remaining in place across the central
Gulf Coast for the first half of next week. This pattern should support
the continued development of diurnally induced showers and
thunderstorms each day. Overall atmospheric moisture content is
expected to also remain fairly static through the period with PW
values and mixing ratios remaining around 1.75 to 2 inches and 15
g/kg respectively. As a result, expect to see continued rain
chances of around 40 to 50 percent each day. Near normal
temperatures of lows in the middle to upper 70s and highs in the
lower 90s are forecast each day.
VFR conditions are expected to prevail through Friday morning. The
main exceptions will be occasional 1-5 NM VSBYS at KHUM in patchy
fog through about 12z. Brief IFR/MVFR conditions could occur later
in isolated to scattered SHRA/TSRA that are most likely to occur in
the afternoon. 22/TD
It`s expected to remain calmer this morning across the marine area
since there is an absence of thunderstorms. There is still expected
to be isolated showers and some thunderstorms developing today,
however nothing that is expected to produce the much stronger winds
and higher waves that occurred over large areas yesterday. Will have
to monitor convection that develops with the upper level shortwave/
vorticity maxima that is moving west-northwest across the north
central/central Gulf of Mexico, however the models suggest most of
this will be in a weakening or dissipating stage as it enters a
subsidence zone in the coastal waters.
Away from convection, prevailing winds will remain generally 10
knots or less with seas 2 feet or less due to a persistent ridge
of high pressure through early next week. 22/TD
DSS code: Green.
Activities: Jefferson Parish public safety support for Grand Isle.
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 93 73 93 74 / 40 20 40 30
BTR 93 74 93 74 / 40 20 40 30
ASD 92 77 92 78 / 30 20 40 30
MSY 91 78 91 79 / 30 20 40 30
GPT 90 79 91 79 / 30 20 40 30
PQL 91 78 91 78 / 20 20 40 30