LIX issues Area Forecast Discussion (AFD) at Nov 17, 11:41 PM CST ...New AVIATION...238
FXUS64 KLIX 180541
AFDLIX
Area Forecast Discussion
National Weather Service New Orleans LA
1141 PM CST Sun Nov 17 2024
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday)
Issued at 235 PM CST Sun Nov 17 2024
Key message...heavy rainfall event looks to be developing for
roughly the eastern 2/3 of our CWFA for Monday night into Tuesday.
Upper ridge centered over the eastern Gulf of Mexico this
afternoon with a deep upper trough near the Arizona-Mexico border,
and weakening Tropical Depression Sara over the Yucatan Peninsula.
At the surface, high pressure was centered over the Carolinas with
a frontal boundary extending from the Great Lakes to west Texas.
Southeast winds were bringing moisture from the Gulf across the
area underneath an inversion around 5,000 feet. Partly to mostly
sunny skies were noted across the area at mid afternoon with
temperatures ranging from the upper 70s to mid 80s. Dew points
were in the lower and middle 60s.
Sara is expected to weaken and eventually dissipate over the
Yucatan during the next 24 hours, at least as a tropical system.
As the upper ridge shifts east to Florida and the upper trough
lifts northeastward from Arizona through the Plains States, some
or most of the moisture from the remnants of Sara will get pulled
northward tomorrow and tomorrow night on 850 MB winds of 40+
knots. This airmass will be unusually moist for mid-November, with
both the GFS and HRRR forecasts indicating precipitable water
values in the 2.2 to 2.5 range across about the eastern half of
the area ahead of the front Monday night and Tuesday morning. It
should be noted that the LIX upper air sounding climatology base
at SPC doesn't include any soundings with precipitable water
values exceeding 2.2 inches beyond November 3rd.
Tonight and most of the daytime hours Monday are actually expected
to remain dry with precipitable water values near or below 1 inch.
Conditions will get somewhat breezy during the day on Monday with
sustained winds near 20 mph. At this point, don't plan on a Wind
Advisory. Rain and thunderstorms are expected to become more
numerous during Monday evening with the primary threat between
midnight Monday night and noon Tuesday. While shear would be
sufficient for strong to severe storms, current forecast soundings
indicate that instability will be rather weak. Forecast rain
amounts of 3-5 inches across a portion of the local area look to
be entirely reasonable with isolated much higher amounts possible.
The one potential failure mode would be if strong storms were to
develop over the Gulf off the Louisiana coast and cut off the best
moisture inflow. With the potential for significantly heavy
rainfall over multiple large urban areas, have opted to issue a
Flood Watch for Monday night through noon Tuesday, generally from
about Hammond to Houma eastward. Later adjustments in areal extent
or timing may be necessary.
Minor coastal flooding will again be an issue tonight during the
high tide cycle on east and southeast facing shorelines. Generally
less than a foot above normally dry ground during high tide
tonight. With the increase in wind speeds on Monday, that's
likely to push somewhat more water into prone places, with current
guidance indicating 1-2 foot inundation possible. Have issued
another Coastal Flood Advisory for tomorrow night. Didn't have
enough confidence in water levels to justify a watch or warning.
Much above normal temperatures to continue through the daytime
hours on Tuesday with low-mid 80s not out of the question,
depending on cloud cover. Cold air likely to lag the frontal
passage by 6-12 hours across the area. If we get several hours of
sunshine Tuesday afternoon, even with northerly winds, guidance
may not be high enough.
&&
.LONG TERM...
(Tuesday night through Saturday night)
Issued at 235 PM CST Sun Nov 17 2024
The good news is that once the moisture gets swept out of the area
Tuesday, that pretty much ends any significant threat of
precipitation for the rest of the forecast package. A trailing
shortwave moving through the western Great Lakes Tuesday night
into Wednesday will usher in significantly cooler and drier air to
the area for the 2nd half of the week into next weekend.
The northern half of the area could see multiple nights with
overnight lows falling into the upper 30s, beginning Wednesday
night. Thursday into Saturday could see high temperatures falling
short of the 70 degree mark, especially on Friday. Our local area
hasn't seen temperatures that cool since mid March for most of the
area.
&&
.AVIATION...
(06Z TAFS)
Issued at 1136 PM CST Sun Nov 17 2024
Through at least 18z, VFR conditions will be the rule at all of
the terminals as some drier air in the mid-levels lingers over the
region. However, after 18z, MVFR ceilings will begin to develop as
a plume of deeper moisture starts to feed in from the Gulf.
Ceilings will fall into MVFR range of 2000 to 3000 feet. There
will be a small chance of seeing some shower and thunderstorm
activity develop after 21z, and this is reflected by PROB30
wording at all of the terminals. After 02z, the combination of an
approaching front and the deep moisture in place will support more
widespread heavy rainfall at all of the terminals. This rainfall
will persist through the end of the forecast cycle. Ceilings and
visibilities will both fall into IFR range with this heavier
rainfall. A few embedded thunderstorms are also expected, but the
probabilities are not high enough to include in the forecast at
this time. PG
&&
.AVIATION...
(00Z TAFS)
Issued at 526 PM CST Sun Nov 17 2024
For the majority of the forecast period, VFR conditions will
remain in place as drier air lingers over the region. However, a
surge of moisture will feed into the area after 20z, and this will
support the development of MVFR stratus ranging from 1500 to 2500
feet at HUM, MSY, and NEW by 22z. At MSY, further stratus build
down is expected after 00z as moisture continues to stream in, and
light rainfall could develop as early 03z resulting in prevailing
IFR conditions.
&&
.MARINE...
Issued at 235 PM CST Sun Nov 17 2024
Will continue the Small Craft Advisories and Exercise Caution
headlines as currently depicted through Monday night with the
likelihood that they will be extended in later forecasts. While
there may be short periods where headlines might not be justified,
marine interests should anticipate hazardous conditions,
especially over the open waters, through much or all of the
workweek.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 61 80 68 80 / 0 30 100 60
BTR 67 85 72 84 / 0 40 100 50
ASD 64 82 71 81 / 0 40 100 90
MSY 68 83 73 81 / 0 50 100 90
GPT 67 80 70 79 / 0 30 100 100
PQL 63 83 72 81 / 0 10 90 100
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch from Monday evening through Tuesday morning for
LAZ039-058>060-064>071-076>082-087>090.
Coastal Flood Advisory until 6 AM CST Monday for LAZ058-060-
066>070-076>078-080-082-084-086-087.
Coastal Flood Advisory from 6 PM Monday to noon CST Tuesday for
LAZ058-060-066>070-076>078-080-082-084-086-087.
GM...Small Craft Advisory until 6 AM CST Tuesday for GMZ550-552-555-
570-572-575-577.
MS...Flood Watch from Monday evening through Tuesday morning for
MSZ077-083>088.
Coastal Flood Advisory until 6 AM CST Monday for MSZ086>088.
Coastal Flood Advisory from 6 PM Monday to noon CST Tuesday for
MSZ086>088.
GM...Small Craft Advisory until 6 AM CST Tuesday for GMZ552-555-570-
572-575-577.
&&
$$
SHORT TERM...RW
LONG TERM....RW
AVIATION...PG
MARINE...RW
Source:
LIX issues Area Forecast Discussion (AFD) at Nov 17, 11:41 PM CST ...New AVIATION...---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
