Deepening low pressure moving from Texas to the Lower Ohio River Valley generated a line of thunderstorms that moved through southern Mississippi and southeast Louisiana during the afternoon hours of the 18th. A wake low developed after the passage of the front, producing several areas of strong winds and minor wind damage.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LIX wrote it up.
Deepening low pressure moving from Texas to the Lower Ohio River Valley generated a line of thunderstorms that moved through southern Mississippi and southeast Louisiana during the afternoon hours of the 18th. A wake low developed after the passage of the front, producing several areas of strong winds and minor wind damage.
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 Apr 18, 3:04 AM CST, 8 hours 24 minutes earlier.
Area Forecast Discussion
National Weather Service New Orleans LA
404 AM CDT Thu Apr 18 2019
.SYNOPSIS...
At 3 am CDT...a 997 mb low was centered over northern Lake
Michigan with a cold front to St. Louis and Wichita Falls. Almost
solid line of thunderstorms from southeast Missouri to near
Texarkana to near Laredo Texas.
Locally, southeast winds in place across the area with much warmer
conditions than last night. Temperatures range from the mid 60s to
lower 70s. Dew points range from near 60 over southwest
Mississippi to the upper 60s along the coastal counties/parishes.
06z VORTEX SE special soundings at LIX/LCH continue to indicate
that modification in the airmass will be necessary before surface
based convection will occur, especially this far east.
&&
.SHORT TERM...
Main forecast issues primarily in the first 18 hours of the
forecast. Potentially pretty significant severe weather/excessive
rainfall/wind issues to deal with.
As noted above, going to need some modification of current
sounding, and we'll see in a few hours how much of that is already
occurring with the 12z routine flight. Upper impulse moving across
west Texas this morning with northern stream shortwave moving
through the lower Missouri River valley. The west Texas shortwave
will be over east Texas by midday and into the lower Ohio River
Valley by midnight tonight, as the Missouri River Valley shortwave
drops southward to near Texarkana at midnight. This will deepen a
1002 mb surface low now in Texas to about 992 mb near Louisville,
KY by midnight tonight. This will serve to enhance the ongoing
convection over the eastern half of Texas as it moves eastward.
Short term guidance indicates that precipitation should remain
fairly isolated through the morning hours before a line of
convection reaches the Atchafalaya River Basin around 18z. The
line will progress eastward across the CWA before exiting into
Alabama in the 03-06z Friday time frame. While main convective
threat will be a QLCS, airmass will certainly be ripe for some
supercellular development in advance of the line. NAM BUFR
soundings are quite concerning. For example, McComb late afternoon
soundings show CAPE values in the 1500-2000 range with 0-1km
helicity values near 500, 0-3km values near 600, 0-6km shear of 70
knots and precipitable water values upwards of 2 inches. While GFS
BUFR sounding values aren't quite as robust, still enough there to
not have us back off of earlier forecast.
All modes of severe weather possible, if not likely. Entire area
outlooked for Enhanced Risk of severe weather and Slight Risk of
Excessive rainfall. Widespread rainfall amounts near 2 inches
indicated west of the Pearl River from the Interstate 12 corridor
northward, and have expanded the Flash Flood Watch westward to the
Atchafalaya River, including just about all of the Baton Rouge
Metro Area, and held on to it until 03z Friday. May eventually
need to include the Mississippi coastal counties, but right now,
system looks progressive enough that threat may be a little lower
there as FF guidance is somewhat higher over those counties. 35
Winds will ramp up over the land areas today as the sfc low deepens
and move across the Lower MS Valley. As the sfc low deepens
(possibly in the mid 990s) we will see a difference of 6-8mb from
the northwest to southeast across the CWA this afternoon with
pressure falls on the order of 6-8mb in 6 hrs. This will lead to a
very tight pressure gradient causing winds to ramp up around midday.
Combine that with a developing LL jet as h925 winds increase to 40-
50kts and we could easily see numerous gusts of 35 to 45 mph
possibly even topping out around 50 mph in a few locations much like
this past Saturday. This could lead to some light tree and power
line damage once again outside of any thunderstorm activity. With
that we have now added a wind advisory to the entire outlook
area from 17z through 3z this evening. /CAB/
Winds will enhance tide levels today, but we are in the neap tide
portion of the cycle, so it appears we may escape coastal flooding
issues in the normally prone locations.
Once the convective/heavy rain/wind threats move eastward tonight,
we'll still have to deal with the upper low moving across the area
on Friday. A good bit of cloud cover can be expected with the
upper low. There are some indications that airmass may be unstable
enough for some low topped convection Friday afternoon that could
produce some rather low topped convection over the northeast
corner of our CWA that could produce small hail, even if it
doesn't produce lightning. Any of this convection would dissipate
after sunset.
Beyond Friday afternoon, dry weather through the weekend, with
rather cool mornings expected Saturday and Sunday. Temperatures
trended toward a GFS/ECMWF blend. 35
&&
.LONG TERM...
Early next week expect dry conditions. Model differences start
creeping in at midweek with southern storm shortwaves. For now,
have kept blended solutions with small PoPs in the forecast at
midweek. Temperatures near to somewhat above normal for late
April, and a blended approach was taken. 35
&&
.AVIATION...
Low ceilings ranging from 1000 to 1500 feet have begun to develop
over the past couple of hours due to the formation of an elevated
temperature inversion. These MVFR ceilings should persist through
around 15z. Winds should also gradually increase overnight with
south winds of 10 to 15 knots expected by the morning hours. After
18z, a band of convection should begin to impact the terminals,
and have a prevailing IFR visibilities and a mention of VCTS in
the forecast between 18z and 02z tomorrow. Timing and eventual
tempo groups reflecting the highest convective risk will likely be
added with the 12z package. Winds will also turn very strong
after 18z tomorrow with south winds of 20 to 30 knots and higher
gusts expected. Low level wind shear issues may arise at some of
the terminals in the late afternoon and early evening hours, and
this is reflected in the forecast. The convective threat should
diminish after 03z tomorrow, but IFR and MVFR ceilings could
linger through the end of the TAF period. 32
&&
.MARINE...
With a sfc low expected to deepen considerably and track across
the Lower MS Valley winds will greatly increase through the day
today. We will see a pressure difference of 5-6mb across the
coastal waters this afternoon. With that onshore flow will pick up
in high end adv criteria with occasional to numerous gale force
gusts beginning around midday across the western waters and
working east through the afternoon. With that we have upgraded
some of the advisory to a gale warning. Winds may slack off a tad
as the front moves into and through the coastal waters overnight
tonight however winds will quickly ramp back up out of the
northwest with gale force gusts anticipated again. Strong cold air
advection and rapidly rising sfc pressure could lead to winds
being rather high and we may be underestimating the winds from
9-15z Friday. Winds will slowly ease through the day and night
Friday however, they will still be in small craft advisory range
till at least sunrise Saturday. High pressure will work east
across the Gulf this weekend and by Sunday afternoon onshore flow
will have returned. /CAB/
&&
.DECISION SUPPORT...
DSS code: Orange.
Deployed: None.
Activation: None.
Activities: River Flood Warning
Enhanced Risk Severe
Slight Risk Excessive Rainfall(Flash Flood watch issued)
Gale Warning and Wind Advisory
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 rain; direct tropical threats; Events of National
Significance.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 77 50 64 41 / 100 50 30 0
BTR 77 53 66 45 / 100 20 10 0
ASD 79 54 68 44 / 100 50 10 0
MSY 79 57 68 49 / 100 50 10 0
GPT 76 55 66 47 / 90 60 20 0
PQL 79 56 68 44 / 100 70 20 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Wind Advisory from noon today to 10 PM CDT this evening for
LAZ034>037-039-040-046>050-056>072.
Flash Flood Watch through this evening for LAZ034>037-039-040-
047-048-050-071-072.
GM...Small Craft Advisory from 1 PM to 4 PM CDT this afternoon for
GMZ552-572.
Small Craft Advisory from 10 AM Friday to 7 AM CDT Saturday for
GMZ530-532-534-536-538-550-552-555-557-570-572-575-577.
Gale Warning from 4 PM this afternoon to 10 AM CDT Friday for
GMZ552-572.
Small Craft Advisory until 1 PM CDT this afternoon for GMZ550-
570.
Small Craft Advisory from 10 PM this evening to 4 AM CDT Friday
for GMZ550-570.
Gale Warning from 1 PM this afternoon to 10 PM CDT this evening
for GMZ550-570.
Gale Warning from 4 AM to 10 AM CDT Friday for GMZ550-570.
Gale Warning from 7 PM this evening to 10 AM CDT Friday for
GMZ532-536-538-555-557-575-577.
Small Craft Advisory from 7 PM this evening to 1 AM CDT Friday
for GMZ530-534.
Gale Warning from 1 AM to 10 AM CDT Friday for GMZ530-534.
MS...Wind Advisory from noon today to 10 PM CDT this evening for
MSZ068>071-077-080>082.
Flash Flood Watch through this evening for MSZ068>071.
GM...Small Craft Advisory from 1 PM to 4 PM CDT this afternoon for
GMZ572.
Small Craft Advisory from 10 AM Friday to 7 AM CDT Saturday for
GMZ532-534-536-538-550-552-555-557-570-572-575-577.
Gale Warning from 4 PM this afternoon to 10 AM CDT Friday for
GMZ572.
Small Craft Advisory until 1 PM CDT this afternoon for GMZ570.
Small Craft Advisory from 10 PM this evening to 4 AM CDT Friday
for GMZ570.
Gale Warning from 1 PM this afternoon to 10 PM CDT this evening
for GMZ570.
Gale Warning from 4 AM to 10 AM CDT Friday for GMZ570.
Gale Warning from 7 PM this evening to 10 AM CDT Friday for
GMZ536-538-555-557-575-577.
Small Craft Advisory from 7 PM this evening to 1 AM CDT Friday
for GMZ534.
Gale Warning from 1 AM to 10 AM CDT Friday for GMZ534.
&&Hazardous Weather Outlook...UPDATED National Weather Service New Orleans LA 1045 AM CDT Thu Apr 18 2019 GMZ530-532-534-536-538-550-552-555-557-570-572-575-577-LAZ034>037- 039-040-046>050-056>072-MSZ068>071-077-080>082-190345- Lake Pontchartrain and Lake Maurepas-Mississippi Sound- Lake Borgne-Chandeleur Sound-Breton Sound- Coastal Waters from Port Fourchon LA to Lower Atchafalaya River LA out 20 nm- Coastal waters from the Southwest Pass of the Mississippi River to Port Fourchon Louisiana out 20 NM- Coastal Waters from Boothville LA to Southwest Pass of the Mississippi River out 20 nm- Coastal waters from Pascagoula Mississippi to Stake Island out 20 NM- Coastal waters from Port Fourchon Louisiana to Lower Atchafalaya River LA from 20 to 60 NM- Coastal waters from Southwest Pass of the Mississippi River to Port Fourchon Louisiana from 20 to 60 NM- Coastal Waters from Stake Island LA to Southwest Pass of the Mississippi River from 20 to 60 nm- Coastal waters from Pascagoula Mississippi to Stake Island Louisiana out 20 to 60 NM-Pointe Coupee-West Feliciana- East Feliciana-St. Helena-Washington-St. Tammany-Iberville- West Baton Rouge-East Baton Rouge-Ascension-Livingston-Assumption- St. James-St. John The Baptist-Upper Lafourche-St. Charles- Upper Jefferson-Orleans-Upper Plaquemines-Upper St. Bernard- Upper Terrebonne-Lower Terrebonne-Lower Lafourche-Lower Jefferson- Lower Plaquemines-Lower St. Bernard-Northern Tangipahoa- Southern Tangipahoa-Wilkinson-Amite-Pike-Walthall-Pearl River- Hancock-Harrison-Jackson- 1045 AM CDT Thu Apr 18 2019 This Hazardous Weather Outlook is for portions of Southeast Louisiana...South Mississippi and the adjacent coastal waters. .DAY ONE...Today and Tonight A Tornado Watch is in effect for areas west of I-55 corridor to Destrahan to Port Fourchon until 7 pm CDT. Additional watches will likely be issued later today. Severe thunderstorms are expected today into mid-evening hours. Damaging wind gusts, tornadoes - some strong, torrential rainfall and large hail will be possible. In addition to the severe weather threat there is a Moderate Risk for excessive rainfall across portions of southwest Mississippi and a few of the adjacent Louisiana parishes. The remainder of the outlook area is under a Slight Risk for excessive rainfall today. Widespread rainfall amounts should be from 1 to 3 inches with isolated higher amounts which could fall in short time. A Flash Flood Watch is now in effect for portions of the area. Gale Warnings and small craft advisories are in effect today and tonight for the coastal waters initially for strong onshore flow ahead of the cold front, then strong offshore flow after the frontal passage. A wind advisory is also in effect later today and into the evening hours for the entire outlook area. Strong winds of 20 to 25 mph with gusts up to 45 mph are expected. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Small craft advisories will remain in effect Friday morning through Saturday morning for the coastal waters. .SPOTTER INFORMATION STATEMENT... Spotter and amateur radio activation is requested for today. Promptly report any storm damage and storm related information to the National Weather Service office in Slidell. 24/RR
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</html>The national radar mosaic for the moment the first event began.
9 thunderstorm wind, 1 hail, 1 flash flood, 1 strong wind. Local standard time, as filed.
Broadcast media relayed a public report of quarter size hail from the Plaquemine area of Iberville Parish.
News footage showed a power pole blown down onto two occupied vehicles on Gretna Boulevard near Sams Club. Broadcast media reported injuries to two occupants of the vehicles.
Social media photos were received of a tree blown down on Rosemound Loop near US Highway 61.
A tree was blown down onto a home in the Dipple Drive area off US Highway 61 near St. Francisville.
Heavy rainfall of 2 to 3 inches within an hour or two caused small stream and drainage ditches to come out of their banks resulting in flooding of multiple side roads in the vicinity of Bluebonnet and Perkins Road.
A tree was reported blown down onto a home in the Pride area near Fire Station 13.
A NWS storm survey showed a 5 mile long path of straight line thunderstorm wind damage north of Louisiana Highway 16 stretching from west to east. Multiple hardwood trees were blown down facing eastward about a mile north of Highway 16. No reports of injuries or fatalities.
Multiple trees were reported blown down on Dummyline Road south of Louisiana Highway 16.
Broadcast media showed footage of power poles leaning and several tree branches down in the area of Louisiana Highways 10 and 450. Event time estimated by radar.
Several trees were reported blown down near the intersection of Louisiana Highway 21 and South Bankston Drive.
A tree was reported blown down across Jim Price Road at Greenwell Springs Road.
A tree was blown down onto a vehicle and power lines were blown down on Spruce Road off of Military Road in Slidell. Winds were in the wake of a line of thunderstorms.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Louisiana in 2019Every state in 2019This day in weather historyWarnings in Louisiana, April 2019
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 2026-10-01. Each event’s entry at NCEI: 809661, 809662, 809663, 809664, 821345, 809665, 809666, 809667, 809668, 809669, 809670, 809671.