Alert archive / Virginia / Flash Flood Warnings in 2018

Flash Flood Warning 87, NWS Baltimore/Washington

October 11, 20185 counties in Virginia

NWS Baltimore/Washington issued this flash flood warning at Oct 11, 2018, 6:23 PM EDT for 5 counties in Virginia. It was in force for 3 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
Oct 11, 2018, 6:23 PM EDT (22:23 UTC)
Expired
Oct 11, 2018, 9:15 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

Counties City of Fredericksburg, VA, King George County, VA, Prince William County, VA, Spotsylvania County, VA, Stafford County, VA

The radar

The Sterling radar (KLWX), 67 km from the middle of the area, began a volume at 22:23 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.4 hours before the alert went out and 64 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, Washington/Dulle, VA at 12:00Z on 2018-10-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 435 joules per kilogram.LCLEL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2018-10-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 177 square meters per square second.193958Sfc1 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
435 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
461 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
177 m²/s²
0-3 km storm-relative helicity
187 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.0

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 Baltimore/Washington wrote its last area forecast discussion before this flash flood warning went out at Oct 11, 3:33 PM EDT, 2 hours 50 minutes earlier.

Area forecast discussion, Oct 11, 3:33 PM EDT, 2 hours 50 minutes before
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Hazardous weather outlook, Oct 11, 6:20 PM EDT, 3 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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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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In the hours before

Local storm report, Oct 11, 3:52 PM EDT, 2 hours 31 minutes before
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<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<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.
      </p>
      <p class="small" id="detail">
        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 Baltimore/Washington issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 10, 8:29 PM EDTCoastal Flood AdvisoryLWXArlington, City of Alexandria, City of Falls Church4 hr
Oct 11, 2:49 AM EDTStorm WarningLWX25 hr
Oct 11, 3:12 AM EDTWind AdvisoryLWXAlbemarle, Amherst, Arlington, Augusta, Fairfax, Fauquier and 15 more29 hr
Oct 11, 1:52 PM EDTSmall Craft AdvisoryLWX36 hr
Oct 11, 2:56 PM EDTFlash Flood WarningLWXAlbemarle, Augusta, Nelson, City of Charlottesville, City of Waynesboro6 hr
Oct 11, 3:39 PM EDTSevere Thunderstorm WarningLWXCulpeper, Fauquier, Orange, Spotsylvania, Stafford34 min
Oct 11, 4:35 PM EDTFlash Flood WarningLWXCulpeper, Orange, Spotsylvania5 hr
Oct 11, 5:47 PM EDTAreal Flood WarningLWXPrince William4 hr
Oct 11, 6:51 PM EDTAreal Flood WarningLWXFairfax, City of Alexandria2 hr
Oct 11, 2:27 PM EDTCoastal Flood AdvisoryLWXBaltimore, City of Baltimore9 hr
Oct 11, 7:59 PM EDTAreal Flood WarningLWXCharles, Prince George's24 hr

Nearby

Flash Flood Warnings in Virginia, 2018Every flash flood warning in 2018

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.