Alert archive / Louisiana / Hurricane Watches in 2021

Hurricane Watch 1009, NWS New Orleans, LA

August 26, 202115 parishes in Louisiana; 5 counties in Mississippi

NWS New Orleans, LA issued this hurricane watch at Aug 26, 2021, 10:09 PM CDT for 15 parishes in Louisiana; 5 counties in Mississippi. It was in force for 36 hr.

The area

The counties it named.

The facts

Issued
Aug 26, 2021, 10:09 PM CDT (03:09 UTC)
Expired
Aug 28, 2021, 10:20 AM CDT
In force
36 hr
Issued by
NWS New Orleans, LA

Counties Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Orleans Parish, LA, Pointe Coupee Parish, LA, Saint Bernard Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Pearl River County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 3.2 hours before the alert went out and 100 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-pSkew-T log-p diagram, Slidell Radar S, LA at 00:00Z on 2021-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2172 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 00:00Z on 2021-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
2172 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
864 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this hurricane watch 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 hurricane watch went out at Aug 26, 6:43 PM CDT, 3 hours 26 minutes earlier.

Area forecast discussion, Aug 26, 6:43 PM CDT, 3 hours 26 minutes before
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In the hours before

Special weather statement, Aug 26, 4:47 PM CDT, 5 hours 22 minutes before
Special Weather Statement
National Weather Service New Orleans LA
447 PM CDT Thu Aug 26 2021

LAZ057>060-065>067-262315-
Lower Terrebonne LA-St. Charles LA-Upper Terrebonne LA-
Lower Lafourche LA-St. John The Baptist LA-St. James LA-
Upper Lafourche LA-
447 PM CDT Thu Aug 26 2021

...Strong thunderstorms will impact portions of southwestern St. John
The Baptist, southeastern St. James, southwestern St. Charles,
eastern Terrebonne and Lafourche Parishes through 615 PM CDT...

At 447 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles northeast of Lockport to Golden Meadow
to 8 miles southwest of Port Fourchon. Movement was northwest 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...
Houma, Cut Off, Galliano, Larose, Lockport, Golden Meadow, Mathews,
Paradis, Des Allemands, South Vacherie, Chauvin, Dulac, Raceland,
Bayou Gauche, Montegut, Leeville, Cocodrie, Chackbay, Tambour Bay
Buoy and Lumcon Center Buoy.

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.

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

&&

LAT...LON 2928 9035 2934 9035 2922 9040 2930 9040
      2935 9043 2927 9048 2928 9058 2922 9056
      2922 9053 2921 9054 2922 9064 2913 9065
      2918 9075 2972 9069 2996 9071 2996 9052
      2968 9024 2934 9018 2909 9023
TIME...MOT...LOC 2147Z 143DEG 19KT 2969 9041 2940 9030 2905 9031

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 10:09 PM CDTStorm Surge WatchLIXAssumption, Orleans, Saint Bernard, Saint James, Saint John the Baptist, Saint Tammany18 hr
Aug 27, 3:34 AM CDTSpecial Marine WarningLIX116 min
Aug 27, 5:27 AM CDTSpecial Marine WarningLIX48 min
Aug 27, 6:19 AM CDTSpecial Marine WarningLIX56 min
Aug 27, 7:12 AM CDTSpecial Marine WarningLIX63 min
Aug 27, 8:34 AM CDTSpecial Marine WarningLIX56 min
Aug 27, 10:10 AM CDTAreal Flood AdvisoryLIXOrleans, Saint Tammany3 hr
Aug 27, 10:17 AM CDTFlash Flood WatchLIXOrleans, Saint Bernard, Saint James, Saint John the Baptist, Saint Tammany12 hr
Aug 27, 12:21 PM CDTSpecial Marine WarningLIX54 min
Aug 27, 4:01 PM CDTHurricane WarningLIXAssumption, East Baton Rouge, East Feliciana, Iberville, Orleans, Pointe Coupee and 9 more60 hr
Aug 27, 4:01 PM CDTTropical Storm WarningLIXAssumption, East Baton Rouge, East Feliciana, Orleans, Saint Bernard, Saint Helena and 5 more24 days
Aug 27, 4:12 PM CDTStorm Surge WarningLIXAssumption, Iberville, Orleans, Saint Bernard, Saint James, Saint John the Baptist and 1 more3 days
Aug 27, 9:37 AM CDTRiver Flood WarningLIXHarrison6 days
Aug 27, 9:37 AM CDTRiver Flood WarningLIXHancock5 days
Aug 27, 9:37 AM CDTRiver Flood WarningLIXHarrison5 days
Aug 27, 9:37 AM CDTRiver Flood WarningLIXHarrison6 days
Aug 27, 10:46 AM CDTTropical Storm WatchLIXAmite, Pearl River, Pike, Walthall, Wilkinson5 hr
Aug 27, 1:28 PM CDTAreal Flood AdvisoryLIXHarrison, Jackson3 hr
Aug 27, 1:44 PM CDTFlash Flood WarningLIXHarrison3 hr

Nearby

Hurricane Watches in Louisiana, 2021Hurricane Watches in Mississippi, 2021Every hurricane watch in 2021

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.