Alert archive / Maryland / Flash Flood Warnings in 2009

Flash Flood Warning 21, NWS Baltimore/Washington

June 10, 2009Carroll County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jun 10, 2009, 6:23 PM EDT for Carroll County, Maryland. It was in force for 3 hr. 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 10, 2009, 6:23 PM EDT (22:23 UTC)
Expired: Jun 10, 2009, 9:15 PM EDT
In force: 3 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

County Carroll County, MD

The radar

The Sterling radar (KLWX), 82 km from the middle of the area, began a volume at 22:26 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.

What was reported inside it

Time	Report	Where	Remark
Jun 10, 6:25 PM EDT	FLASH FLOOD	Westminster, MD	NUMEROUS ROADS UNDER WATER.
Jun 10, 7:00 PM EDT	FLASH FLOOD	Westminster, MD	A NUMBER OF STREETS CLOSED IN DOWNTOWN WESTMINSTER DUE TO HIGH WATER

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.4 hours before the alert went out and 80 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: 13 J/kg
Mixed-layer CIN: -219 J/kg
Mixed-layer LCL: 980 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 21 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS51 KLWX 102223
FFWLWX
MDC013-110115-
/O.NEW.KLWX.FF.W.0021.090610T2223Z-090611T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
623 PM EDT WED JUN 10 2009

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CARROLL COUNTY IN NORTH CENTRAL MARYLAND

* UNTIL 915 PM EDT

* AT 622 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  FLASH FLOODING FROM A THUNDERSTORM OVER THE WARNED AREA.

* SOME LOCATIONS THAT WILL CONTINUE TO BE AFFECTED BY THE HEAVY   
  RAIN INCLUDE WESTMINSTER AND CARROL COUNTY REGIONAL AIRPORT.

LAT...LON 3966 7708 3968 7691 3959 7691 3956 7696
      3956 7711

$$
JRK

1 follow-up statement

000 
WGUS71 KLWX 102304
FFSLWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
704 PM EDT WED JUN 10 2009

MDC013-110115-
/O.CON.KLWX.FF.W.0021.000000T0000Z-090611T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CARROLL MD-
704 PM EDT WED JUN 10 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM EDT FOR
CARROLL COUNTY...

AT 653 PM EDT...NATIONAL WEATHER SERVICE EMPLOYEE REPORTED A 
THUNDERSTORM PRODUCING FLASH FLOODING ALONG LITTLE PIPE CREEK 
BETWEEN BOND STREET AND MIAMI AVENUE.

NATIONAL WEATHER SERVICE DOPPLER RADAR HAS ESTIMATED OVER 3 INCHES 
OF RAIN HAS FALLEN IN THE PAST TWO HOURS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 3966 7708 3968 7691 3959 7691 3956 7696
      3956 7711

$$
JRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 10, 5:42 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Carroll, Frederick, Harford	48 min
Jun 10, 5:50 PM EDT	Flash Flood Warning	LWX	Montgomery	3 hr
Jun 10, 6:25 PM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Prince George's	50 min
Jun 10, 6:33 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Carroll, Frederick, Howard	42 min
Jun 10, 6:51 PM EDT	Flash Flood Warning	LWX	Prince George's	3 hr
Jun 10, 6:59 PM EDT	Severe Thunderstorm Warning	LWX	Montgomery, Prince George's	46 min

Nearby

Flash Flood Warnings in Maryland, 2009 Every flash flood warning in 2009

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.