A strong warm front across southeast Louisiana aided the development of showers and thunderstorms during the afternoon hours. Gusty winds were also associated with the warm front.
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The episode as NWS LIX wrote it up.
A strong warm front across southeast Louisiana aided the development of showers and thunderstorms during the afternoon hours. Gusty winds were also associated with the warm front.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS New Orleans, LA wrote its last area forecast discussion before the first event at Mar 4, 12:07 PM CST, 2 hours 53 minutes earlier.
Area Forecast Discussion
National Weather Service New Orleans LA
1207 PM CST Wed Mar 4 2020
.AVIATION/MESOANALYSIS...
Frontal boundary currently off the Mississippi coast westward
across Lake Pontchartrain. North of the boundary, temperatures in
the lower and middle 60s, south of the boundary, temperatures near
80 with dew points in the lower 70s. South winds gusting above 20
knots at the New Orleans terminals would indicate significant low
level convergence along the front, and don't expect much further
south penetration of the front for now.
18z LIX sounding showing saturation up to about 850 mb, but very
unstable lapse rates 7-8C/km in the mid-levels. Many severe
parameters describing favorable conditions for severe weather,
just waiting for a lifting mechanism. Certainly going to have to
watch things closely this afternoon.
Visibilities have improved over the last few hours with the
exception of KGPT. South of the front, conditions primarily VFR
for now, with IFR to the north of the front. CAMs models continue
to indicate convective initiation within the next couple of hours,
moving along the Interstate 10 corridor, with things winding down
after 00z. Behind the system, anticipate IFR ceilings to
predominate at least through 18z Thursday. 35
&&
.MARINE...
For now, plan is to let Fog Advisory expire, web cams over Lake
Pontchartrain and observations/cams near the LA and MS coasts
aren't showing any real indications of fog. May be some out there,
but not as widespread as earlier. 35
&&
.PREV DISCUSSION... /issued 325 AM CST Wed Mar 4 2020/
DISCUSSION...
Likely the most impactful weather of the week will take place
over the next 24 hours. An upper low is currently tracking across
northern Mexico. A residual frontal boundary that moved into the
region yesterday is stalled across southern/central Mississippi
and Louisiana. It will be the short-term focus for severe
potential over the next several hours. Local thermodynamics are
rather weak at the current time with a cap is in place but that
looks to be changing soon as warm air advection in the low levels
combined with cooling in the mid levels erodes the warm nose and
steepens lapse rates. Shear is relatively decent from central MS
down to the LA/MS border in SW Mississippi. Meso models indicate
that this corridor from southwest to central MS will be the main
region where supercell development potential is greatest.
Southwest MS and the adjacent LA parish are about the farthest
south that severe storms should develop, which is why the TOR
watch is out for those areas. In fact, it will probably be a
typical WFOLIX situation where that SW MS region will be the
"launching pad", meaning storms will just becoming severe as they
move into JAN/MOB CWA's.
By mid morning, the boundary in MS will slide south, effectively
shunting surface based potential in SW MS. After a late morning
lull, models show a surface low will be tracking east along the
Louisiana coastline. The appendant warm front will provide the
focus for another round of severe potential. This time, it looks
like the main region will be south of I-12, from Houma to New
Orleans. Baton Rouge may have a hour or 2 window of opportunity,
but thats it as the front moves through them quickly and a strong
inversion develops. Model sounding at MSY shows quite high
uninhibited CAPE (2400j/kg) and LI's up to -8. Low level shear and
SRH are on the low side at 100m2/s2 for SRH and 20-30kts of
shear. Low shear/high CAPE environments are notoriously over
achievers for the local CWA. Thinking big hail, by New Orleans
standards, and a few tornadoes are possible in this warm sector.
Not sure if shear can support a strong tornado, but at least
thinking along those lines as a possibility. 21Z to 06Z is looking
like the general window of greatest threat.
Other impacts for the day are heavy rainfall and fog. Areas of light
to moderate fog are in place for much of the CWA. Guidance
suggesting may be dealing with at least some fog/hazy conditions all
day between showers and storms. Those storms could be intense enough
at time to result in flash flooding as PW's approach 1.8" per model
soundings and some training in possible.
The area should be quickly clearing out before sunrise Thursday as
the upper low races eastward. Skies my stay cloudy for much of the
day, but the rain should be done. Temps will be slightly cooler than
normal Thursday but quickly bounce back to and rise above climo
Friday into the weekend. Should even stay clear of rain through the
weekend. Rain looks to be retuning on Monday with the next fast
moving trough.
MEFFER
AVIATION...
Ceilings will be all over the place today from LIFR to MVFR. Vis
restrictions will also be up and down through these same categories.
We will also couple this with some prevailing -SHRA and TSRA groups
through the day and overnight. These conditions may linger into
Thursday morning and clear with fropa.
MARINE...
Fog looks to remain an issue over most waters again today. The dense
fog advisory over marine areas will be left in its current time
frame but this may be extended in time as a cold front stalls near
the coast this morning. Fog may be an issue once again tonight as
well ahead of a cold front that should move through improving vis
conditions Thursday morning.
As the cold front stalls near the coast this morning it will begin
to evolve into a warm front as a sfc low moves into the area tonight
into early Thursday. This will cause winds over the lakes and
Mississippi Sound to become easterly and weaker around 10kt. The
remaining marine areas will retain southerly winds of around 15kt
rising to 20-25kt tonight as the sfc low tracks NE over the western
portion of the coastal waters. Once the cold front passes through
the northern gulf Thursday morning it will caus winds to rapidly
shift to W around 20kt then gradually become NW through the day.
Winds will then begin to shift to N and finally to E by the weekend
and ease back to around 10-15kt. As the sfc low lifts out of the
gulf today into tonight it will help develop strong possibly severe
thunderstorms mainly over the lakes and sounds while the remainder
of the coastal waters should see only some showers and possibly a
few thunderstorms but are not expected to be severe.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 71 54 65 47 / 100 90 20 0
BTR 75 55 65 47 / 100 90 10 0
ASD 76 56 67 48 / 80 80 10 0
MSY 78 59 67 53 / 70 70 0 0
GPT 71 57 66 49 / 80 80 20 0
PQL 73 58 70 46 / 100 90 20 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flash Flood Watch through late tonight for LAZ034>037-039-040-
046>050-071-072.
GM...Dense Fog Advisory until noon CST today for GMZ530-532-534-536-
538-550-552-555-557.
MS...Flash Flood Watch through late tonight for MSZ068>071-077-
080>082.
GM...Dense Fog Advisory until noon CST today for GMZ532-534-536-538-
550-552-555-557.
&&The national radar mosaic for the moment the first event began.
1 strong wind. Local standard time, as filed.
Minor wind damage to a home in Woodville, MS. Time estimated. Report relayed by West Feliciana Louisiana Parish EOC.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Mississippi in 2020Every state in 2020This day in weather historyWarnings in Mississippi, March 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 882779.