Alert archive / Maryland / Flash Flood Warnings in 2021

Flash Flood Warning 4, NWS Baltimore/Washington

June 9, 2021Saint Mary's County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jun 9, 2021, 7:35 PM EDT for Saint Mary's County, Maryland. It was in force for 95 min. 2 reports 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
Jun 9, 2021, 7:35 PM EDT (23:35 UTC)
Expired
Jun 9, 2021, 9:10 PM EDT
In force
95 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Saint Mary's County, MD

The radar

The Dover AFB radar (KDOX), 112 km from the middle of the area, began a volume at 23:39 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

TimeReportWhereRemark
Jun 9, 7:45 PM EDTFLASH FLOOD2 Nne Piney Point, MDA CAR WAS STRANDED IN HIGH WATER ON LOCUST GROVE DRIVE AT SAINT MARY'S RIVER.
Jun 9, 8:07 PM EDTFLASH FLOOD2 Wnw Dameron, MDMD-5 POINT LOOKOUT ROAD IMPASSABLE DUE TO FLOWING WATER BOTH WAYS AT VILLA ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.6 hours before the alert went out and 100 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, Wallops Is Stn, VA at 12:00Z on 2021-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 795 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2021-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.1939Sfc1 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
795 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
967 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

332 
WGUS51 KLWX 092335
FFWLWX
MDC037-100245-
/O.NEW.KLWX.FF.W.0004.210609T2335Z-210610T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
735 PM EDT Wed Jun 9 2021

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  Southeastern St. Marys County in southern Maryland...

* Until 1045 PM EDT.

* At 735 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Doppler radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that may experience flash flooding include...
  Lexington Park...                  Piney Point...
  Tall Timbers...                    Saint Marys City...
  Saint Marys River...               Saint George Island...
  Saint Inigoes Creek...             Town Creek...
  California...                      Patuxent River Naval Air 
  Station...
  Drayden...                         Park Hall...
  Great Mills...                     Valley Lee...
  Callaway...                        Saint Inigoes...
  Dameron...                         Ridge...
  Scotland...

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

&&

LAT...LON 3830 7659 3833 7656 3833 7651 3832 7648
      3829 7644 3829 7643 3813 7630 3810 7630
      3808 7640 3811 7650 3813 7653 3821 7657

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

BKF
1 follow-up statement
527 
WGUS71 KLWX 100110
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
910 PM EDT Wed Jun 9 2021

MDC037-100120-
/O.CAN.KLWX.FF.W.0004.000000T0000Z-210610T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Marys MD-
910 PM EDT Wed Jun 9 2021

...FLASH FLOOD WARNING FOR SOUTHEASTERN ST. MARYS COUNTY HAS BEEN 
REPLACED WITH A FLOOD WARNING...

LAT...LON 3830 7659 3833 7656 3833 7651 3832 7648
      3829 7644 3829 7643 3813 7630 3810 7630
      3808 7640 3811 7650 3813 7653 3821 7657

$$

BKF

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 5:14 PM EDTSevere Thunderstorm WarningLWXSaint Mary's46 min
Jun 9, 6:09 PM EDTSevere Thunderstorm WarningLWXSaint Mary's30 min
Jun 9, 6:55 PM EDTAreal Flood WarningLWXSaint Mary's2 hr

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.