Alert archive / Maryland / Flash Flood Warnings in 2022

Flash Flood Warning 77, NWS Baltimore/Washington

September 12, 2022Baltimore County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Sep 12, 2022, 6:18 PM EDT for Baltimore 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 12, 2022, 6:18 PM EDT (22:18 UTC)
Expired
Sep 12, 2022, 9:30 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

County Baltimore County, MD

The radar

The Sterling radar (KLWX), 91 km from the middle of the area, began a volume at 22:22 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, 10.3 hours before the alert went out and 87 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 2022-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 666 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, Washington/Dulle, VA at 12:00Z on 2022-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
666 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
559 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
88 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 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 12, 3:31 PM EDT, 2 hours 47 minutes earlier.

Area forecast discussion, Sep 12, 3:31 PM EDT, 2 hours 47 minutes before
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Hazardous weather outlook, Sep 12, 5:31 PM EDT, 47 minutes before
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In the hours before

Local storm report, Sep 12, 3:18 PM EDT, 3 hours before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
318 PM EDT MON SEP 12 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     TSTM WND DMG     2 SE ALANTHUS           38.52N  77.90W
09/12/2022                   CULPEPER           VA   EMERGENCY MNGR

            NUMEROUS TREES DOWN NEAR THE INTERSECTION OF FARLEY
            ROAD AND ALANTHUS ROAD.

&&

EVENT NUMBER LWX2204964

ADM
Local storm report, Sep 12, 4:28 PM EDT, 1 hour 50 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.
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 9:04 PM EDTCoastal Flood AdvisoryLWXArlington, King George, City of Alexandria, City of Falls Church14 hr
Sep 12, 2:52 AM EDTFlood WatchLWXArlington, Clarke, Fairfax, Frederick, Loudoun, Page and 6 more17 hr
Sep 12, 5:15 AM EDTDense Fog AdvisoryLWXAlbemarle, Amherst, Augusta, Clarke, Culpeper, Fauquier and 17 more4 hr
Sep 12, 2:08 PM EDTSevere Thunderstorm WarningLWXCulpeper, Fauquier37 min
Sep 12, 2:11 PM EDTAreal Flood WarningLWXClarke, Frederick, Warren, City of Winchester103 min
Sep 12, 2:37 PM EDTTornado WarningLWXCulpeper, Fauquier23 min
Sep 12, 4:01 PM EDTSpecial Marine WarningLWX89 min
Sep 12, 4:28 PM EDTSevere Thunderstorm WarningLWXPrince William, Stafford47 min
Sep 12, 4:52 PM EDTTornado WarningLWXFairfax, Prince William23 min
Sep 12, 5:20 PM EDTSpecial Marine WarningLWX55 min
Sep 12, 5:33 PM EDTSpecial Marine WarningLWX87 min
Sep 12, 5:38 PM EDTSpecial Marine WarningLWX78 min
Sep 12, 5:41 PM EDTAreal Flood WarningLWXArlington, Fairfax, Prince William, City of Alexandria, City of Fairfax, City of Falls Church and 2 more3 hr
Sep 12, 5:53 PM EDTSpecial Marine WarningLWX61 min
Sep 12, 6:59 PM EDTSpecial Marine WarningLWX46 min
Sep 12, 7:15 PM EDTSpecial Marine WarningLWX60 min
Sep 12, 4:10 PM EDTAreal Flood WarningLWXBaltimore6 hr
Sep 12, 5:28 PM EDTAreal Flood WarningLWXBaltimore, Carroll5 hr
Sep 12, 6:28 PM EDTSevere Thunderstorm WarningLWXCharles, Saint Mary's32 min

Nearby

Flash Flood Warnings in Maryland, 2022Every flash flood warning in 2022

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.