Alert archive / Louisiana / Flash Flood Watches in 2009

Flash Flood Watch 2, NWS New Orleans, LA

March 25, 200912 parishes in Louisiana; 5 counties in Mississippi

NWS New Orleans, LA issued this flash flood watch at Mar 25, 2009, 3:51 PM CDT for 12 parishes in Louisiana; 5 counties in Mississippi. It took effect at Mar 25, 2009, 4:00 PM CDT. It was in force for 63 hr.

The area

The counties it named.

The facts

Issued: Mar 25, 2009, 3:51 PM CDT (20:51 UTC)
In effect from: Mar 25, 2009, 4:00 PM CDT
Expired: Mar 28, 2009, 7:00 AM CDT
In force: 63 hr
Issued by: NWS New Orleans, LA
Flood severity: None

Counties Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Pointe Coupee Parish, LA, Saint Bernard Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist 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 12:00Z, 8.9 hours before the alert went out and 110 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: 529 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 552 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 263 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.5

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood 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 flash flood watch went out at Mar 25, 3:51 PM CDT, 0 minutes earlier.

Area forecast discussion, Mar 25, 3:51 PM CDT, 0 minutes before

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Hazardous weather outlook, Mar 25, 3:49 PM CDT, 2 minutes before

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In the hours before

Special weather statement, Mar 25, 12:00 PM CDT, 3 hours 51 minutes before

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<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 25, 3:19 PM CDT	Small Craft Advisory	LIX		4 days

Nearby

Flash Flood Watches in Louisiana, 2009 Flash Flood Watches in Mississippi, 2009 Every flash flood watch in 2009

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.