Scientific Forecaster Discussion
fxus64 klix 170920
Area forecast discussion
National Weather Service New Orleans la
420 am CDT Thu Oct 17 2019
surface analysis showed the old cold front from central Florida to
west Gulf to an inverted trough/low over Bay of Campeche. In
addition, an expansive 1020mb high was located from northeast
Texas to mid Mississippi Valley.
Upper air analysis showed a high over Cuba, a weakness over
southwest Gulf of Mexico, and deep low over Texas Big Bend. In
addition, a negatively tilted main trough from Lake Michigan to
northeast Continental U.S.. circulation around the high and main trough has
created a confluent flow from forecast area to North Florida.
cold air advection will be strong enough to keep high temps about
5 to 7 degrees below norms today. Surface high will slowly slide
east over Ohio Valley. In the Gulf, a broad area of low pressure
is forecast to move northeast to the northern and northeast Gulf
Friday into Saturday. Euro and GFS are in better agreement with
the low over the north central Gulf by Friday morning...Euro
brings the low closer to Mississippi Delta than GFS. Warm waters
in the low to mid 80s and relatively light winds will give a short
window for some development today. The upper level low over Texas
is expected over the south Louisiana and Louisiana coastal waters
by Friday morning. This is a cold core system and southwest winds
ahead of this low will cause some interaction but lifting
northeast possibly Friday into Saturday. Northeast wind flow and
astronomical high tide will yield elevated tide levels late
tonight through Saturday. The close proximity will yield gusty
winds and periods over heavy rainfall across land areas near the
coast Friday and Saturday.
The system will continue to lift northeast and dry condition will
occur across the area Saturday through Sunday. A vigorous wave
will track east across The Rockies late Saturday and Mississippi
Valley Sunday night. This feature will drive a strong cold front
through the forecast area Monday with possibly strong storms
Monday day period. High pressure will build in the area next
Tuesday and Wednesday.
VFR conditions will persist at all of the terminals through the
evening hours. After midnight, low stratus should begin to develop
over a few of the terminals south of Lake Pontchartrain. Ceilings
of 2000 to 3000 feet could be in place by 06z at khum, kmsy, and
knew. These ceilings should continue to push further inland by
12z, and expect to see all of the terminals except for kmcb in
MVFR conditions at that time. Pg
a developing area of low pressure will produce a tighter pressure
gradient over the coastal waters today into tonight as it
approaches from the southwest. East-northeast winds of 15 to 20
knots will persist over nearly all of the waters during this
period, and seas of 3 to 5 feet can also be expected. As the low
pushes through the coastal waters tomorrow into tomorrow night,
Small Craft Advisory conditions are expected to develop. Northeast
and north winds of 20 to 30 knots and seas of 6 to 9 feet are
expected to develop over the open Gulf waters and sounds. The
tidal lakes will see winds of 15 to 20 knots and waves of 2 to 3
feet. The low will pull away from the waters on Saturday. Winds
will turn westerly and gradually decrease to 10 to 15 knots by the
late afternoon hours. Seas will also gradually improve as the
winds decrease, but seas of 5 to 7 feet are still expected to due
added swell over the eastern waters into Saturday evening. High
pressure is expected to briefly settle over waters on Sunday, and
winds and seas should decrease to 5 to 10 knots and 1 to 3 feet.
However, another low pressure system and associated cold front
will impact the waters on Monday and Tuesday. Onshore flow of 15
to 20 knots is expected on Monday, and winds will shift to an
offshore flow by Tuesday at 20 to 25 knots in the wake of the
passing cold front. Seas of 5 to 7 feet are also expected by
Dss code: blue.
Deployed: forecaster deployed to support city of New Orleans for
Activities: forecast support to city of New Orleans for building
collapse. Monitoring possible tropical development in Gulf.
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; marginal risk severe or excessive rain.
Yellow = heightened impacts with short-fused watch, warning or
advisory issuances; radar support for slight risk severe
or excessive rain.
Orange = high impacts; enhanced risk severe; nearby tropical events;
hazmat or other large episodes.
Red = full engagement for moderate to high risk of severe and/or
excessive rainfall, or direct tropical threats; events of
Preliminary point temps/pops...
mcb 70 51 72 55 / 0 10 20 20
btr 70 56 73 57 / 0 10 20 20
asd 73 56 74 60 / 10 10 40 40
msy 73 65 76 66 / 10 10 50 40
gpt 72 57 72 61 / 10 10 50 50
pql 73 55 72 60 / 10 10 50 50