Flash Flood Warning 34, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
123 PM CDT Thu May 21 2026

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1241 PM CDT Thu May 21 2026

- Expect high rain chances through the next several days. 7 day
rainfall totals will range from 4 to 7 inches in the northwest to
less than an inch of much of coastal MS and extreme SELA.

&&

.SHORT TERM...
(Now through Sunday night)
Issued at 1241 PM CDT Thu May 21 2026

The upper level pattern hasn't changed much lately. A cutoff low is
located over the western Atlantic east of Florida while broad scale
troughing encompasses nearly the entire CONUS except the
southeastern portion of the country. Both low level southeast flow
and mid level southwest flow continue to transport deep layer
moisture into the local region. Evidence of this is clearly shown
on the 12Z KLIX sounding, which had a PW of 2.07 inches (only
0.06 inches below the daily record value). This highlights just
how moist and summer-like the airmass has become across the
forecast area. Model soundings show little change through the
afternoon and evening hours, with PW values generally remaining
between 2.0 and 2.2 inches.

Mid level lapse rates and deep layer shear remain too weak to
support an organized severe weather threat. However, storms will
still be capable of producing very heavy rainfall rates given the
deep moisture profile and warm cloud depths in place. Localized
hourly rainfall rates of 2 to 4 inches per hour will be possible
within the strongest cores this afternoon and evening. The weak
steering flow regime, combined with Corfidi vectors generally below
20 knots, may allow for slow moving or occasionally backbuilding
convection, especially near boundary interactions. This raises
concern for localized training of storms and isolated flash
flooding, particularly in urban and poor drainage areas.

Going into the overnight period, confidence remains lower regarding
the evolution of any additional convective rounds tied to subtle
impulses moving through the broad trough. CAM guidance remains split
between sparse overnight showers versus another organized cluster of
storms capable of producing a localized flash flooding threat.

Generally speaking, Friday looks like a similar pattern with
another round of scattered to numerous showers and thunderstorms
capable of producing torrential rainfall and localized flooding
impacts. Warm and humid conditions combined with considerable
cloud cover should continue to limit overnight cooling. It will
certainly feel like early summer as lows struggle to fall below
the lower to middle 70s. A quick look at record warm low
temperatures shows forecast lows may approach records at several
locations across the CWA.

MEFFER
&&

.LONG TERM...
(Monday through Wednesday night)
Issued at 1241 PM CDT Thu May 21 2026

An unsettled and moisture rich pattern will persist through much of
the extended forecast period as broad ridging remains suppressed to
the south and east while weak troughing lingers across the entire
region. Daily rounds of predominately (but not definite) diurnally
driven showers and thunderstorms are expected each afternoon through
the weekend and into\ early next week.

Precipitable water values generally between 1.8 and 2.2 inches will
continue to support efficient warm rain processes and locally heavy
rainfall with any thunderstorms that develop. Rainfall coverage may
fluctuate somewhat day to day depending on subtle mesoscale
boundaries, convective overturning from prior day activity, and
shortwaves passing through the base of the broad scale trough... but
overall confidence remains high in continued high daily POPs. High
temperatures will remain near climatological normals but lows above
normal due to increased cloud cover and precipitation coverage.

Although widespread flooding is not anticipated at this time,
isolated nuisance flooding and localized flash flooding issues will
remain possible each day, especially in urban areas and locations
that receive repeated rounds of convection.

MEFFER
&&

.AVIATION...
(18Z TAFS)
Issued at 1241 PM CDT Thu May 21 2026

Showers and storms have been impacting terminals off/on all
morning long. Threat of TSRA may wane some this afternoon and
evening but potential exists for new development during the
overnight period. Main impacts will be torrential rainfall which
lower visibilities and lightning strikes. Will handle that
potential with TEMPO and PROB30 groups.

&&

.MARINE...
Issued at 1241 PM CDT Thu May 21 2026

Persistent onshore flow of 10 to 15 knots will remain in place
through this with high pressure generally centered east of the local
coastal waters. Seas will remain well below any hazardous limits at
1 to 3 feet through this period. As we move into the back half of
the week, we will see a weak cold front drift south towards the
coast and stall along the northern Gulf Coast. That'll lead to both
weaker winds overall as well as north or south winds depending on
coastal zone's location in related to the boundary. A stronger upper
level trough moves through the region Saturday morning. Expect to
see at least Exercise Caution, possibly low in Small Craft Advisory,
conditions behind this front.

MEFFER
&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

SHORT TERM...ME
LONG TERM....ME
AVIATION...ME
MARINE...ME

Special Weather Statement
National Weather Service New Orleans LA
1244 PM CDT Thu May 21 2026

LAZ039-MSZ070-071-077-211830-
Washington LA-Pike MS-Walthall MS-Pearl River MS-
1244 PM CDT Thu May 21 2026

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF NORTHEASTERN
WASHINGTON PARISH, WALTHALL, SOUTHEASTERN PIKE AND NORTHWESTERN PEARL
RIVER COUNTIES THROUGH 130 PM CDT
...

At 1242 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Tylertown to near Varnado. Movement was north
at 20 mph.

HAZARD...Winds in excess of 30 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Bogalusa, Tylertown, Varnado, Salem, Crossroads, Dexter, and Angie.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3133 9008 3134 9004 3118 9003 3117 9000
      3113 9000 3113 8994 3107 8992 3107 8984
      3100 8983 3100 8968 3070 8969 3104 9031
      3135 9022 3135 9011
TIME...MOT...LOC 1742Z 193DEG 19KT 3110 9015 3096 8982

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Special Weather Statement
National Weather Service New Orleans LA
246 PM CDT Thu May 21 2026

LAZ039-079-MSZ077-212015-
Washington LA-Northern St. Tammany LA-Pearl River MS-
246 PM CDT Thu May 21 2026

...A STRONG THUNDERSTORM WILL IMPACT PORTIONS OF NORTH CENTRAL ST.
TAMMANY, SOUTHEASTERN WASHINGTON PARISHES IN SOUTHEASTERN LOUISIANA
AND WEST CENTRAL PEARL RIVER COUNTIES THROUGH 315 PM CDT
...

At 245 PM CDT, Doppler radar was tracking a strong thunderstorm over
Bush, or 11 miles south of Bogalusa, moving north at 15 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Bogalusa, Sun, Crossroads, and Bush.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3051 8983 3053 9001 3085 8996 3076 8966
TIME...MOT...LOC 1945Z 200DEG 13KT 3061 8990

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

TJS

Special Weather Statement
National Weather Service New Orleans LA
303 PM CDT Thu May 21 2026

LAZ039-079-MSZ077-212045-
Washington LA-Northern St. Tammany LA-Pearl River MS-
303 PM CDT Thu May 21 2026

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF NORTHEASTERN ST.
TAMMANY, SOUTHEASTERN WASHINGTON PARISHES IN SOUTHEASTERN LOUISIANA
AND SOUTHWESTERN PEARL RIVER COUNTIES THROUGH 345 PM CDT
...

At 303 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms capable of producing funnel clouds along a line
extending from Bush to 6 miles north of Pearl River to near Picayune.
Movement was north at 5 mph.

HAZARD...Funnel clouds and winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...If a funnel cloud briefly touches down, minor damage to
         outdoor objects is possible. Gusty winds could knock down
         tree limbs and blow around unsecured objects.

Locations impacted include...
Bogalusa, Picayune, Poplarville, Pearl River, Sun, Bush, Mcneil, and
Crossroads.

This includes the following Interstates...
 Interstate 59 in Louisiana between mile markers 7 and 11.
 Interstate 59 in Mississippi between mile markers 1 and 31.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in New Orleans.

&&

LAT...LON 3065 8955 3056 8957 3050 8963 3050 8965
      3048 8965 3046 8967 3046 8969 3044 8968
      3036 8976 3057 8999 3083 8993 3087 8946
TIME...MOT...LOC 2003Z 197DEG 5KT 3062 8992 3046 8979 3058 8966

FUNNEL CLOUDS...POSSIBLE
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

TJS