Alert archive / Virginia / Flash Flood Warnings in 2003

Flash Flood Warning 135, NWS Baltimore/Washington

September 23, 20034 counties in Virginia; Frederick County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Sep 23, 2003, 4:25 AM EDT for 4 counties in Virginia; Frederick County, Maryland. 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: Sep 23, 2003, 4:25 AM EDT (08:25 UTC)
Expired: Sep 23, 2003, 7:30 AM EDT
In force: 3 hr
Issued by: NWS Baltimore/Washington
Area: Counties, with a storm outline in the text

Counties Frederick County, MD, Clarke County, VA, Fauquier County, VA, Loudoun County, VA, Warren County, VA

The radar

The Sterling radar (KLWX), 29 km from the middle of the area, began a volume at 08:26 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 00:00Z, 8.4 hours before the alert went out and 38 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: 7 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 918 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 281 m²/s²
0-3 km storm-relative helicity: 400 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 Baltimore/Washington wrote its last area forecast discussion before this flash flood warning went out at Sep 23, 3:50 AM EDT, 35 minutes earlier.

Area forecast discussion, Sep 23, 3:50 AM EDT, 35 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Hazardous weather outlook, Sep 22, 3:45 PM EDT, 12 hours 40 minutes before

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-
050>057-WVZ048>055-231000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
345 PM EDT MON SEP 22 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MARYLAND WEST OF THE CHESAPEAKE
BAY AND EAST OF GARRETT COUNTY...THE DISTRICT OF COLUMBIA...NORTHERN
VIRGINIA...THE NORTHERN AND CENTRAL SHENANDOAH VALLEY...AND THE
EASTERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...TONIGHT...
RAIN AND ISOLATED THUNDERSTORMS WILL MOVE OVER THE AREA TONIGHT.
SOME OF THE RAIN COULD BE LOCALLY HEAVY. A FLOOD WATCH IS IN EFFECT
IN THE MOUNTAINS AND FOOTHILLS. THERE COULD BE WIND GUSTS OF 30 TO
40 MPH IN THE HEAVIEST SHOWERS.

.DAYS TWO THROUGH SEVEN...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED.

RDH

In the hours before

Local storm report, Sep 23, 3:33 AM EDT, 52 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Local storm report, Sep 23, 4:00 AM EDT, 25 minutes before

<!doctype html>
<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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 23, 1:13 AM EDT	Flash Flood Warning	LWX	Fauquier	3 hr
Sep 23, 1:37 AM EDT	Flash Flood Warning	LWX	Loudoun	3 hr
Sep 23, 1:49 AM EDT	Flash Flood Warning	LWX	Clarke, Warren	3 hr
Sep 23, 5:43 AM EDT	Flash Flood Warning	LWX	Fairfax, City of Fairfax	2 hr
Sep 23, 7:06 AM EDT	Special Marine Warning	LWX		114 min
Sep 23, 2:25 AM EDT	Flash Flood Warning	LWX	Carroll	3 hr
Sep 23, 2:43 AM EDT	Flash Flood Warning	LWX	Montgomery	3 hr
Sep 23, 5:15 AM EDT	Flash Flood Warning	LWX	Carroll	3 hr

Nearby

Flash Flood Warnings in Virginia, 2003 Flash Flood Warnings in Maryland, 2003 Every flash flood warning in 2003

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.