Gale Warning 6, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
1137 PM CST Thu Mar 10 2022

.AVIATION...06Z TAF Package...VFR conditions will continue for now
but cigs will begin to develop overnight and lower through the
morning and day. BKN/OVC cigs below 4k will likely hold off for
quite a while but by tomorrow afternoon most terminals will likely
see cigs hovering around 2500-4k ft. Convection is mainly a
concern this morning closer to the coast but in the afternoon and
evening convection will be a problem across the entire area. The
strong cold front will begin to move through the CWA during the
evening and should at least be through BTR and MCB before 6z but
could be through or at HDC. /CAB/

&&

.PREV DISCUSSION... /issued 252 PM CST Thu Mar 10 2022/

SHORT TERM...
Tonight through Saturday...
Tonight, a boundary is expected to set up in the coastal waters.
Southerly surface winds will help to bring moister and warm air
into the environment. Looking at the models, conditions will be
dry tonight over the land areas with the chance of scattered
showers in the marine areas.

Friday, an upper level shortwave/frontal boundary is expected to
influence the area (and merge with a longwave trough in the NE US).
Scattered to numerous showers and storms will be possible, mainly in
the afternoon hours looking at the models. Southerly surface winds
ahead of the storms will allow for warm air and moisture advection
into the area. Weak upper level divergence will allow for some
lifting in the environment as well. Strong to possibly severe storms
will be possible, looking at the models, especially along the MS
coastal areas. The more favorable parameters for strong storms will
be in place along the MS coast as the system moves through the area.
Lightning and gusty winds will be possible inside of stronger
storms, especially during the afternoon hours.

Another hazard worth noting is the trends in the models to show
strong post-frontal gradient winds. General model consensus shows
winds 20+ mph starting late Friday evening and running through
Saturday. A wind advisory may be needed for this time period, so
that will need to be monitored closely over the next day.

Saturday, an upper level low pressure system is expected to phase
with the shortwave trough and move off the east coast of the US.
Northerly surface winds will act to enhance cold air advection and
dry air advection into the area. Weak upper level convergence will
act to enhance some sinking and stable air in the environment. Based
on the models, Saturday will be fairly dry overall.

Saturday night into Sunday, the setup looks to be favorable for
radiational cooling, so temperatures will be lower than average
Sunday morning. Lighter winds (especially north of Lake
Pontchartrain), clear skies, and CAA will allow for temperatures
to overachieve guidance for the low temperatures. As a result, low
temperatures on Sunday morning were bumped down several (2-4
degrees) degrees from the NBM to account for this and be more in
line with the general model guidance. Lows on Sunday morning are
forecast to be in the mid 20s to low 30s across the area. MSW

LONG TERM...
Sunday through Wednesday...
Sunday, upper level ridging will dominate the pattern as the
front moves off the eastern coast of the US. Southerly surface
winds will act to enhance warm air advection and moisture
advection into the area. Weak upper level divergence will act to
enhance some lifting in the environment. Looking at the models,
conditions will be dry Sunday as it is mainly a transition day for
the atmosphere.

Monday, zonal flow will dominate the upper level pattern. Southerly
surface winds will act to continue to enhance warm air advection and
moisture advection in the environment. Weak upper level divergence
will act to enhance lifting in the environment. Looking at the
models, scattered showers and storms will be possible Tuesday,
mainly during the afternoon hours. There is still some uncertainty
in the models regarding timing of the best instability. In general,
lightning will be possible with these storms along with some gusty
winds.

Tuesday, a low pressure system will influence the area as a front is
expected to move through. Southerly to southeasterly surface winds
ahead of the front will continue to enhance warm air and moisture
advection into the environment. Weak upper level divergence will act
to enhance some lifting in the environment ahead of the system.
Given the placement of the low and the amount of moisture
availability and some instability, we could see the chance for
strong to severe storms on Tuesday. Lightning and gusty winds would
be the main threats based on the models. There is some model
disagreement, especially regarding the timing of the system.
Currently, the parameters favorable for severe weather are not
maximized when the front will be moving through. If the front slows
down some (so that it pushes through in the afternoon hours), then
it will be more likely to see strong to severe storms.

Wednesday, the low pressure system is forecast to be moving off the
east coast of the US. Northerly surface winds will act to enhance
cold air advection and dry air advection into the area. Upper level
convergence will enhance advection of sinking and more stable air
into the environment. Looking at the models, Wednesday will see dry
conditions. MSW

AVIATION...
18Z TAF Package...
VFR conditions prevail at all area airports. LIFR conditions are
forecast at most area airports late tonight overnight through the
morning hours tomorrow. Vicinity showers and scattered showers
will be possible at most coastal area airports tomorrow morning
and afternoon, which will contribute to these lower ceilings and
visibilities. Additionally, fog will be possible around daybreak
at many area airports, which will contribute to the lower ceilings
and visibilities at that time. Conditions will improve to MVFR
and IFR conditions by the end of the forecast period. MSW

MARINE...
Tonight through Friday afternoon, winds will be southerly and
moderate (<15 knots). Friday evening through Saturday afternoon,
winds will be very strong (25-35 knots) and northerly. Winds will
be gusting to 45 kts during this time period as well. As a result,
a Gale Watch as been issued for late Friday evening through
Saturday evening. Saturday evening through Sunday afternoon, winds
will be northerly to northeasterly and strong (15-25 knots).
Sunday evening through Tuesday morning, winds will be strong
(15-20 knots) and southerly. Tuesday through Wednesday afternoon,
winds will be northerly and strong (15-20 knots). Wednesday
afternoon through Thursday evening, winds will be southerly to
southeasterly and moderate (<15 knots). Thursday evening through
Friday morning, winds will be strong (15-20 knots) and southerly.
Wave heights will correspond to the wind speeds. MSW

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  47  74  34  48 /  20  60  80   0
BTR  50  75  37  52 /  20  70  80   0
ASD  53  76  39  53 /  30  70  90   0
MSY  57  75  41  52 /  30  70  90   0
GPT  55  73  40  53 /  40  80  90   0
PQL  53  74  37  53 /  40  70  90   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Gale Watch from late Friday night through Saturday afternoon for
     GMZ530-532-534-536-538-550-552-555-557-570-572-575-577.

MS...None.
GM...Gale Watch from late Friday night through Saturday afternoon for
     GMZ532-534-536-538-550-552-555-557-570-572-575-577.

&&