Alert archive / Maryland / Flash Flood Warnings in 2021
Flash Flood Warning 70, NWS Baltimore/Washington
NWS Baltimore/Washington issued this flash flood warning at Sep 15, 2021, 7:22 PM EDT for Frederick County, Washington County, Maryland. It was in force for 64 min. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Sep 15, 2021, 7:22 PM EDT (23:22 UTC)
- Expired
- Sep 15, 2021, 8:26 PM EDT
- In force
- 64 min
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Flood severity
- None
Counties Frederick County, MD, Washington County, MD
The radar
The Sterling radar (KLWX), 79 km from the middle of the area, began a volume at 23:25 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 15, 7:35 PM EDT | FLOOD | 3 E Smithsburg, MD | EDGEMONT CREEK FLOWING ACROSS PLEASANT VALLEY ROAD. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 11.4 hours before the alert went out and 82 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.
- Mixed-layer CAPE
- 13 J/kg
- Mixed-layer CIN
- -270 J/kg
- Mixed-layer LCL
- 1457 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 73 m²/s²
- 0-3 km storm-relative helicity
- 106 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
459
WGUS51 KLWX 152322
FFWLWX
MDC021-043-160230-
/O.NEW.KLWX.FF.W.0070.210915T2322Z-210916T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
722 PM EDT Wed Sep 15 2021
The National Weather Service in Sterling Virginia has issued a
* Flash Flood Warning for...
North Central Frederick County in north central Maryland...
Northeastern Washington County in north central Maryland...
* Until 1030 PM EDT.
* At 722 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 3 inches of rain
have fallen. The expected rainfall rate is 1 to 2 inches in 1
hour. Additional rainfall amounts of 1 to 2 inches are possible in
the warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Life threatening flash flooding. Thunderstorms
producing flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets and underpasses.
* Some locations that will experience flash flooding include...
Smithsburg... Cavetown...
Sabillasville... Fort Ritchie...
Cascade... Highfield...
This includes the following streams and drainages...
Owens Creek, Friends Creek, Antietam Creek, Little Antietam Creek,
Grove Creek and Beaver Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3965 7759 3965 7762 3967 7756 3969 7752
3972 7748 3972 7747 3972 7745 3972 7741
3966 7750
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
RCM1 follow-up statement
443
WGUS71 KLWX 160026
FFSLWX
Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
826 PM EDT Wed Sep 15 2021
MDC021-043-160036-
/O.CAN.KLWX.FF.W.0070.000000T0000Z-210916T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Frederick MD-Washington MD-
826 PM EDT Wed Sep 15 2021
...FLASH FLOOD WARNING IS CHANGED TO A FLOOD WARNING FOR NORTH
CENTRAL FREDERICK AND NORTHEASTERN WASHINGTON COUNTIES IN NORTH
CENTRAL MARYLAND...
The heavy rain has ended. Flash flooding is no longer expected to
pose a threat. A flood warning has replaced this flash flood
warning. Please continue to heed remaining road closures.
LAT...LON 3965 7759 3965 7762 3967 7756 3969 7752
3972 7748 3972 7747 3972 7745 3972 7741
3966 7750
$$
RCMThe office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 15, 2:54 PM EDT | Coastal Flood Advisory | LWX | Anne Arundel, Baltimore, Harford, City of Baltimore | 13 hr |
| Sep 15, 3:45 PM EDT | Severe Thunderstorm Warning | LWX | Allegany | 16 min |
| Sep 15, 5:15 PM EDT | Severe Thunderstorm Warning | LWX | Washington | 30 min |
| Sep 15, 5:42 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Washington | 48 min |
| Sep 15, 5:52 PM EDT | Areal Flood Warning | LWX | Washington | 115 min |
| Sep 15, 5:52 PM EDT | Severe Thunderstorm Warning | LWX | Washington | 38 min |
| Sep 15, 6:20 PM EDT | Flash Flood Warning | LWX | Washington | 2 hr |
| Sep 15, 6:23 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Washington | 52 min |
| Sep 15, 6:28 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Washington | 34 min |
| Sep 15, 6:35 PM EDT | Areal Flood Warning | LWX | Frederick, Washington | 113 min |
Nearby
Flash Flood Warnings in Maryland, 2021Every flash flood warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.