Alert archive / Mississippi / Flash Flood Warnings in 2026

Flash Flood Warning 77, NWS New Orleans, LA

June 18, 2026Saint Tammany Parish, Louisiana; Hancock County, Pearl River County, Mississippi

NWS New Orleans, LA issued this flash flood warning at Jun 18, 2026, 7:00 AM CDT for Saint Tammany Parish, Louisiana; Hancock County, Pearl River County, Mississippi. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 18, 2026, 7:00 AM CDT (12:00 UTC)
Expired: Jun 18, 2026, 11:30 AM CDT
In force: 5 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Saint Tammany Parish, LA, Hancock County, MS, Pearl River County, MS

The radar

The Hammond radar (KHDC), 70 km from the middle of the area, began a volume at 12:00 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 0.0 hours before the alert went out and 203 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 245 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 617 m above ground
0-6 km bulk shear: 141 kt
0-1 km storm-relative helicity: -954 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Jun 18, 6:18 AM CDT, 42 minutes earlier. Its key messages:

Updated at 613 AM CDT Thu Jun 18 2026
Potential for Life Threatening Flash Flooding. A Particularly Dangerous and Life Threatening Flash Flood Situation exists with a High Risk of Flooding across portions of south Mississippi and southeast Louisiana, especially east of Interstate 55. Considerable Flash Flooding is likely and Catastrophic Flash Flooding is possible today.
A Flood Watch is in effect through Friday morning for most of southeast Louisiana as well as all of southwest and coastal Mississippi.
Tornado Watch 348 in effect until 6 AM CDT for most of the area.
Dangerous conditions for mariners of small craft and minor coastal flooding on south facing shores west of the Mississippi River will persist through tonight as Post Tropical Cyclone Arthur moves into southwest Louisiana.
Extreme heat is expected this weekend. Heat advisories will likely be issued for heat index values of around 110 degrees.

Area forecast discussion, Jun 18, 6:18 AM CDT, 42 minutes before

Area Forecast Discussion
National Weather Service New Orleans LA
618 AM CDT Thu Jun 18 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 613 AM CDT Thu Jun 18 2026

- Potential for Life Threatening Flash Flooding. A Particularly
  Dangerous and Life Threatening Flash Flood Situation exists with
  a High Risk of Flooding across portions of south Mississippi and
  southeast Louisiana, especially east of Interstate 55.
  Considerable Flash Flooding is likely and Catastrophic Flash
  Flooding is possible today.

- A Flood Watch is in effect through Friday morning for most of
  southeast Louisiana as well as all of southwest and coastal
  Mississippi.

- Tornado Watch 348 in effect until 6 AM CDT for most of the area.

- Dangerous conditions for mariners of small craft and minor
  coastal flooding on south facing shores west of the Mississippi
  River will persist through tonight as Post Tropical Cyclone
  Arthur moves into southwest Louisiana.

- Extreme heat is expected this weekend. Heat advisories will
  likely be issued for heat index values of around 110 degrees.

&&

.UPDATE...
Issued at 354 AM CDT Thu Jun 18 2026

Updated Key Messages for WPC's High Risk of Excessive Rainfall
today for portions of the area. Likely to have a fairly large
stripe of 6 to 10 inch rainfall with isolated totals significantly
higher from Houma and Thibodaux northeastward.

&&

.SHORT TERM...
(Now through Sunday)
Issued at 1220 AM CDT Thu Jun 18 2026

Post Tropical Cyclone Arthur has degenerated to a low pressure
area along the Upper Texas Coast. The remnants will continue to
track across western Louisiana overnight and will reach the
Carolinas coastlines by Friday morning. We've already seen some
rotation in radar data, and expect we'll have short-lived spinups
overnight. Additionally, we remain highly concerned about extreme
rainfall amounts overnight. We already had 2.3 inch precipitable
water values at 00z, with guidance indicating that values near 2.6
inches are possible/likely overnight as a 35-40 knot low level jet
plugs in. The 02Z HRRR, for instance, has a large area of rainfall
totals in excess of 6 inches across the area by mid-afternoon
Thursday with spot totals approaching or exceeding 10 inches. If
these totals, or anything close are realized, we're probably
looking at major flooding in those areas. No changes to Flood
Watch anticipated. Could still be scattered precipitation into
Thursday evening associated with this system before we start
seeing some slight drying.

With precipitable water values remaining near 2 inches through
Sunday, still plenty of moisture available for scattered
convection, even without large scale forcing to aid in producing
lift. The large scale heavy rainfall threat will diminish beyond
Thursday evening, but localized heavy rain still possible. Could
also see a few microbursts on Friday.

A second issue over the weekend will be heat stress. We'll likely
see at least some sunshine at times Friday through the weekend
that will allow temperatures to get into the lower, or possibly
middle 90s in many areas. With dew points likely in the upper 70s
to near 80, and lots of residual moisture on the ground, it's
going to be steamy. Likely to have heat index values near our 108
degree criteria for Heat Advisories in many areas on Friday and
possibly again on Sunday. This will be addressed once we get past
the rainfall and tornado issues this morning. Overnight lows may
have trouble getting below 80 degrees for several nights.

&&

.LONG TERM...
(Sunday night through Wednesday)
Issued at 1220 AM CDT Thu Jun 18 2026

Ridging sets up over the northern Gulf for the first half of next
week. However, shortwaves will be tracking west to east just north
of the local area. If we are going to have a day that is
completely dry, it'll probably be Monday. Similar to the weekend,
we'll have to monitor for potential Heat Advisories, especially
Monday. For Tuesday and Wednesday, the question will be exactly
when storms develop. If they develop early enough in the day, that
would blunt the heat somewhat. For now, will stick with the NBM
forecast temperatures with several days seeing highs in the lower
and middle 90s.

&&

.AVIATION...
(12Z TAFS)
Issued at 613 AM CDT Thu Jun 18 2026

Large area of SHRA/TSRA moving across most terminals early this
morning with IFR or lower conditions. Main exceptions are KHUM and
KBTR, where convection has moved east for now. Eastern terminals
could still see gusts to around 40 knots as convection moves
through. The current area of convection should be east of all
terminals by 18z, but with abundant moisture still in place,
afternoon heating could redevelop TSRA. Expect any remaining
precipitation to dissipate after sunset, but MVFR ceilings could
redevelop before sunrise.

&&

.MARINE...
Issued at 1220 AM CDT Thu Jun 18 2026

Strong southerly winds of 20 to 25 knots with gusts of 30 knots
will remain in place over the coastal waters through tonight and
into Thursday and seas of 6 to 9 feet can be expected in the open
Gulf waters. Small craft advisories remain in effect due to these
conditions. Moving into the weekend and early next week, a broad
area of high pressure will build back over the eastern Gulf
waters. Persistent onshore winds of 10 to 15 knots and seas of 2
to 4 feet can be expected from Friday through early next week.

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch through Friday morning for LAZ034>037-039-046>048-
     056>058-064-071-076>087-089-090-092-094-096-098>100.

GM...Small Craft Advisory until 6 AM CDT Friday for GMZ529-531>536-
     541-543-551-553-554-557-570-572-575-577.

MS...Flood Watch through Friday morning for MSZ068>071-077-083>088.

GM...Small Craft Advisory until 6 AM CDT Friday for GMZ531>536-541-
     543-551-553-554-557-570-572-575-577.

&&

SHORT TERM...RW
LONG TERM....RW
AVIATION...RW
MARINE...RW

In the hours before

Local storm report, Jun 18, 6:40 AM CDT, 20 minutes before

Preliminary Local Storm Report
National Weather Service New Orleans LA
640 AM CDT Thu Jun 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0540 AM     Tstm Wnd Dmg     1 S Harahan             29.93N 90.21W
06/18/2026                   Jefferson          LA   Trained Spotter

            Trained spotter reported minor sign,
            powerline and tree damage from possible
            tornado crossing the Mississippi River near
            Waggaman.

&&

MEFFER

Local storm report, Jun 18, 6:43 AM CDT, 17 minutes before

Preliminary Local Storm Report
National Weather Service New Orleans LA
643 AM CDT Thu Jun 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0545 AM     Tstm Wnd Dmg     2 ESE Metairie          29.99N 90.15W
06/18/2026                   Jefferson          LA   Trained Spotter

            Trained spotter reported minor sign,
            powerline and tree damage over portions of
            Metairie from possible tornado.

&&

MEFFER

Local storm report, Jun 18, 6:44 AM CDT, 16 minutes before

Preliminary Local Storm Report
National Weather Service New Orleans LA
644 AM CDT Thu Jun 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0550 AM     Tstm Wnd Dmg     2 NE Metairie           30.02N 90.14W
06/18/2026                   Jefferson          LA   Trained Spotter

            Trained spotter reported minor sign,
            powerline and tree damage near the Lakefront
            from possible tornado.

&&

MEFFER

Local storm report, Jun 18, 6:47 AM CDT, 13 minutes before

Preliminary Local Storm Report
National Weather Service New Orleans LA
647 AM CDT Thu Jun 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0546 AM     Tstm Wnd Dmg     3 NNW New Orleans       30.01N 90.11W
06/18/2026                   Orleans            LA   Public

            Large tree limb downed by thunderstorm
            winds, possible tornado, in Lakeview area.

&&

MEFFER

Local storm report, Jun 18, 6:54 AM CDT, 6 minutes before

Preliminary Local Storm Report
National Weather Service New Orleans LA
654 AM CDT Thu Jun 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0653 AM     Flash Flood      4 NNW Kenner            30.03N 90.27W
06/18/2026                   Jefferson          LA   Broadcast Media

            Reports of several cars stalled due to
            flooding near the intersection of West
            Esplanade and Loyola.

&&

MEFFER

Local storm report, Jun 18, 7:00 AM CDT, 0 minutes before

Preliminary Local Storm Report
National Weather Service New Orleans LA
700 AM CDT Thu Jun 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0659 AM     Flash Flood      2 WNW Slidell           30.30N 89.81W
06/18/2026                   St. Tammany        LA   Public

            High water along Gause Boulevard in Slidell.

&&

MEFFER

The office that day

Everything else NWS New Orleans, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 17, 7:15 PM CDT	Special Weather Statement	LIX	Saint John the Baptist	45 min
Jun 17, 7:21 PM CDT	Special Marine Warning	LIX		84 min
Jun 17, 7:54 PM CDT	Special Weather Statement	LIX	Saint John the Baptist	51 min
Jun 17, 8:10 PM CDT	Special Weather Statement	LIX	Tangipahoa	35 min
Jun 17, 9:08 PM CDT	Special Weather Statement	LIX	Saint John the Baptist	37 min
Jun 17, 9:29 PM CDT	Special Marine Warning	LIX		91 min
Jun 17, 9:32 PM CDT	Special Weather Statement	LIX	Tangipahoa	43 min
Jun 17, 9:42 PM CDT	Special Weather Statement	LIX	Saint Charles	33 min
Jun 17, 9:53 PM CDT	Special Marine Warning	LIX		82 min
Jun 17, 10:05 PM CDT	Special Weather Statement	LIX	Saint Tammany, Washington	55 min
Jun 17, 11:01 PM CDT	Special Marine Warning	LIX		89 min
Jun 17, 11:51 PM CDT	Special Weather Statement	LIX	Terrebonne	39 min
Jun 18, 12:11 AM CDT	Areal Flood Advisory	LIX	Lafourche, Terrebonne	4 hr
Jun 18, 12:22 AM CDT	Special Weather Statement	LIX	Terrebonne	38 min
Jun 18, 12:39 AM CDT	Tornado Warning	LIX	Terrebonne	31 min
Jun 18, 1:01 AM CDT	Tornado Warning	LIX	Lafourche	44 min
Jun 18, 1:20 AM CDT	Special Marine Warning	LIX		55 min
Jun 18, 1:28 AM CDT	Special Weather Statement	LIX	Terrebonne	47 min
Jun 18, 1:40 AM CDT	Special Marine Warning	LIX		49 min
Jun 18, 1:43 AM CDT	Tornado Warning	LIX	Lafourche, Saint Charles	36 min
Jun 18, 1:48 AM CDT	Severe Thunderstorm Warning	LIX	Terrebonne	57 min
Jun 18, 1:49 AM CDT	Areal Flood Advisory	LIX	Assumption, Lafourche, Terrebonne	4 hr
Jun 18, 1:54 AM CDT	Tornado Warning	LIX	Lafourche, Terrebonne	36 min
Jun 18, 1:58 AM CDT	Tornado Warning	LIX	Terrebonne	47 min
Jun 18, 2:05 AM CDT	Tornado Warning Tornado observed	LIX	Saint Charles	25 min
Jun 18, 2:22 AM CDT	Tornado Warning	LIX	Terrebonne	53 min
Jun 18, 2:28 AM CDT	Special Marine Warning	LIX		47 min
Jun 18, 2:31 AM CDT	Flash Flood Warning	LIX	Assumption, Lafourche, Terrebonne	4 hr
Jun 18, 2:36 AM CDT	Special Weather Statement	LIX	Saint John the Baptist	39 min
Jun 18, 2:37 AM CDT	Areal Flood Advisory	LIX	Saint Charles, Saint John the Baptist	3 hr
Jun 18, 2:42 AM CDT	Areal Flood Advisory	LIX	Lafourche	3 hr
Jun 18, 3:04 AM CDT	Severe Thunderstorm Warning	LIX	Lafourche, Terrebonne	41 min
Jun 18, 3:09 AM CDT	Tornado Warning Tornado observed	LIX	Lafourche, Terrebonne	35 min
Jun 18, 3:14 AM CDT	Flash Flood Warning	LIX	Lafourche, Saint Charles, Saint James, Saint John the Baptist	5 hr
Jun 18, 3:22 AM CDT	Tornado Warning	LIX	Jefferson, Saint Charles, Saint John the Baptist	46 min
Jun 18, 3:30 AM CDT	Flash Flood Warning	LIX	Lafourche, Terrebonne	3 hr
Jun 18, 3:34 AM CDT	Tornado Warning	LIX	Lafourche, Saint Charles	41 min
Jun 18, 3:40 AM CDT	Severe Thunderstorm Warning	LIX	Lafourche, Saint Charles, Terrebonne	50 min
Jun 18, 3:41 AM CDT	Tornado Warning	LIX	Lafourche, Terrebonne	49 min
Jun 18, 3:57 AM CDT	Special Marine Warning	LIX		93 min
Jun 18, 4:06 AM CDT	Tornado Warning	LIX	Lafourche	39 min
Jun 18, 4:18 AM CDT	Tornado Warning	LIX	Saint Charles	27 min
Jun 18, 4:26 AM CDT	Severe Thunderstorm Warning	LIX	Jefferson, Lafourche, Orleans, Saint Charles, Terrebonne	64 min
Jun 18, 4:33 AM CDT	Flash Flood Warning	LIX	Jefferson, Orleans, Saint Charles	3 hr
Jun 18, 4:33 AM CDT	Tornado Warning	LIX	Jefferson	18 min
Jun 18, 4:38 AM CDT	Tornado Warning	LIX	Lafourche, Saint Charles	24 min
Jun 18, 4:49 AM CDT	Special Marine Warning	LIX		41 min
Jun 18, 4:50 AM CDT	Special Marine Warning	LIX		40 min
Jun 18, 4:54 AM CDT	Tornado Warning Tornado observed	LIX	Saint Charles	22 min
Jun 18, 4:56 AM CDT	Tornado Warning	LIX	Saint Tammany	25 min
Jun 18, 5:07 AM CDT	Flash Flood Warning	LIX	Saint Tammany	6 hr
Jun 18, 5:08 AM CDT	Tornado Warning	LIX	Jefferson, Saint Charles	39 min
Jun 18, 5:16 AM CDT	Tornado Warning	LIX	Jefferson	13 min
Jun 18, 5:28 AM CDT	Severe Thunderstorm Warning	LIX	Jefferson, Lafourche, Orleans, Saint Bernard, Saint Charles, Saint John the Baptist	62 min
Jun 18, 5:30 AM CDT	Special Marine Warning	LIX		90 min
Jun 18, 5:32 AM CDT	Tornado Warning	LIX	Jefferson, Orleans	32 min
Jun 18, 5:50 AM CDT	Special Marine Warning	LIX		85 min
Jun 18, 6:03 AM CDT	Flash Flood Warning	LIX	Saint Tammany	3 hr
Jun 18, 6:12 AM CDT	Flash Flood Warning Considerable damage threat	LIX	Jefferson, Orleans, Saint Charles	3 hr
Jun 18, 6:41 AM CDT	Tornado Warning	LIX	Saint Tammany	34 min
Jun 18, 6:51 AM CDT	Tornado Warning	LIX	Saint Tammany	24 min
Jun 18, 7:02 AM CDT	Tornado Warning Tornado observed	LIX	Saint Tammany	43 min
Jun 18, 7:03 AM CDT	Severe Thunderstorm Warning Considerable damage threat	LIX	Orleans, Saint Tammany	42 min
Jun 18, 7:09 AM CDT	Special Marine Warning	LIX		66 min
Jun 18, 7:32 AM CDT	Tornado Warning	LIX	Saint Tammany	11 min
Jun 18, 7:55 AM CDT	Areal Flood Advisory	LIX	Pointe Coupee	102 min
Jun 18, 7:59 AM CDT	Special Marine Warning	LIX		91 min
Jun 18, 8:07 AM CDT	Severe Thunderstorm Warning	LIX	Saint Tammany	38 min
Jun 18, 8:21 AM CDT	Tornado Warning	LIX	Saint Tammany	23 min
Jun 18, 8:38 AM CDT	Flash Flood Warning	LIX	Saint Tammany, Washington	3 hr
Jun 18, 9:37 AM CDT	Flash Flood Warning	LIX	Pointe Coupee, West Feliciana	6 hr
Jun 18, 10:08 AM CDT	River Flood Warning	LIX	Tangipahoa	6 hr
Jun 18, 10:08 AM CDT	River Flood Warning	LIX	Tangipahoa	53 hr
Jun 18, 10:10 AM CDT	River Flood Warning	LIX	East Baton Rouge	70 hr
Jun 18, 10:10 AM CDT	River Flood Warning	LIX	Ascension, Livingston	21 days
Jun 18, 10:10 AM CDT	River Flood Warning	LIX	Tangipahoa	10 hr
Jun 18, 10:58 AM CDT	Heat Advisory	LIX	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more	32 hr
Jun 18, 11:17 AM CDT	Areal Flood Warning	LIX	Saint Tammany	6 hr
Jun 18, 11:26 AM CDT	Special Marine Warning	LIX		64 min
Jun 18, 11:27 AM CDT	Special Marine Warning	LIX		63 min

Nearby

Flash Flood Warnings in Mississippi, 2026 Flash Flood Warnings in Louisiana, 2026 Every flash flood warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.