Severe Thunderstorm Warning 104, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
813 PM CST Tue Nov 29 2022

...New UPDATE, AVIATION...

.UPDATE...
Issued at 742 PM CST Tue Nov 29 2022

Earlier convection over southwest Mississippi has shifted well to
the northeast. There's been isolated showers west of Interstate 55
over the last couple of hours, but no significant deep convection.
We're not done with thunderstorms for the night by any means,
though. Storms near the frontal boundary will likely move into
northwest sections of the area around midnight or so, likely
passing east of the area before sunrise Wednesday. Shear profiles
at that point won't be nearly as strong as they had been during
the afternoon hours, but with more than sufficient instability, a
severe weather and heavy rainfall threat continues overnight.

With a Flood Watch already in effect, and at least some threat of
heavy rainfall, won't get in a hurry to cancel the watch.

Will make adjustments to hourly temperatures and dew points to fit
current trends, but with the main remaining threat much later in
the night, no significant changes to products are imminent.

&&

.SHORT TERM...
(Tonight through Wednesday night)
Biggest forecast concerns outside of this afternoon's round of
severe thunderstorms will be a secondary round of showers and
thunderstorms in the overnight hours where the cold front proper
passes through the area. Current timing has it approximately in
the 3 AM to 7 AM range with CAM guidance showing a broken line of
showers of storms sweeping from the northwest to the southeast
into the coastal waters. The storms overnight won't have as much
of the dynamics that the storms earlier today had access to, but
still can't rule out any isolated damaging winds, hail or
possibly a tornado.

Heavy rainfall is also a concern especially as the line congeals
together. PW values are high for this time of year (LIX last
sounding had around 1.5 in which is right at the 90% moving
average). Any thunderstorms will be highly efficient rainmakers
overnight. The storms do look to be progressive but a few areas
could easily pick up 1 to 3 inches of rain.

In addition to all the other threats there is a small window of
stronger non convective/gradient winds possible as strong winds
aloft could mix down to the surface now through later tonight.
Based on observations and the potential time frame (the best
mixing would happen after peak heating), current thinking is the
chances of this happening will be slim and relatively isolated. So
because of this, decided against a wind advisory.

&&

.LONG TERM...
(Thursday through Monday night)
Starting Thursday, the weather is much more benign as high
pressure builds in from the Gulf of Mexico. Dry and warmer
conditions are expected with possibly a slight chance of
precipitation on Saturday with a subtle shortwave from the north
pushing in. Otherwise the next chance of rain falls just outside
of the tail end of this forecast period.

&&

.AVIATION...
(00Z TAFS)
Issued at 742 PM CST Tue Nov 29 2022

Most terminals reporting IFR or lower conditions, but there are a
few with MVFR ceilings (KBTR/KMCB). Have tried to focus TSRA in
2-3 hour window just before frontal passage. The 06z TAF package
will continue to refine the timing. Direct impacts will be IFR or
lower conditions. Wind gusts in excess of 25 knots will be likely
at most or all terminals, both with the TSRA and post- frontal.
Post frontal improvement to VFR likely to occur during the late
morning hours on Wednesday from west to east.

&&

.MARINE...
Winds will remain southerly through tonight before swapping to
strong northerly winds as a strong cold front pushing through the
area into the coastal waters. A small craft advisory will come
into effect tonight and will remain in effect through Thursday
morning for the tidal lakes/sounds and through the afternoon for
everywhere else. Winds will then begin shift to easterly and
slowly relax in speed. There may be a small window this weekend
where small craft exercise caution may be needed in the eastern
coastal waters but that is currently low in confidence. -BL

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  54  64  35  60 /  90  10   0   0
BTR  60  69  38  63 /  80  10   0   0
ASD  63  73  37  64 /  90  30   0   0
MSY  65  72  46  61 / 100  30   0   0
GPT  66  73  41  63 /  90  40   0   0
PQL  65  74  39  62 /  90  50   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch until 7 AM CST Wednesday for LAZ039-076-079-080.

GM...Small Craft Advisory until 3 AM CST Thursday for GMZ530-532-534.

     Small Craft Advisory until noon CST Thursday for GMZ536-538-550-
     552-555-557-570-572-575-577.

MS...Flood Watch until 7 AM CST Wednesday for MSZ071-077-080>082.

GM...Small Craft Advisory until 3 AM CST Thursday for GMZ532-534.

     Small Craft Advisory until noon CST Thursday for GMZ538-550-552-
     555-557-570-572-575-577.

&&

SHORT TERM...BL
LONG TERM....BL
AVIATION/UPDATE...RW
MARINE...BL

Special Weather Statement
National Weather Service New Orleans LA
811 PM CST Tue Nov 29 2022

MSZ069-300300-
Amite MS-
811 PM CST Tue Nov 29 2022

...A strong thunderstorm will impact portions of Amite County through
900 PM CST...

At 811 PM CST, Doppler radar was tracking a strong thunderstorm near
Gloster, or 9 miles west of Liberty, moving northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Liberty, Gloster and Smithdale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3117 9055 3100 9092 3113 9106 3119 9106
      3135 9080 3135 9055
TIME...MOT...LOC 0211Z 238DEG 37KT 3112 9095

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Frye

Special Weather Statement
National Weather Service New Orleans LA
934 PM CST Tue Nov 29 2022

LAZ034>036-MSZ068-300415-
East Feliciana LA-Pointe Coupee LA-West Feliciana LA-Wilkinson MS-
934 PM CST Tue Nov 29 2022

...A strong thunderstorm will impact portions of West Feliciana,
northwestern Pointe Coupee, northwestern East Feliciana Parishes in
southeastern Louisiana and southeastern Wilkinson Counties through
1015 PM CST...

At 934 PM CST, Doppler radar was tracking a strong thunderstorm near
Batchelor, or 12 miles southeast of Simmesport, moving northeast at
45 mph.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Woodville, Wakefield, Fort Adams, Lettsworth, Spillman and Batchelor.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3134 9114 3088 9115 3079 9175 3097 9173
      3103 9165 3102 9165 3097 9166 3100 9163
      3104 9156 3108 9157 3135 9119
TIME...MOT...LOC 0334Z 244DEG 38KT 3091 9162

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

Frye