Alert archive / Maryland / Flash Flood Warnings in 2008

Flash Flood Warning 21, NWS Baltimore/Washington

September 27, 2008Baltimore County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Sep 27, 2008, 8:49 AM EDT for Baltimore County, Maryland. It was in force for 113 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 27, 2008, 8:49 AM EDT (12:49 UTC)
Expired: Sep 27, 2008, 10:42 AM EDT
In force: 113 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

County Baltimore County, MD

The radar

The Sterling radar (KLWX), 89 km from the middle of the area, began a volume at 12:49 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 27, 8:49 AM EDT	FLASH FLOOD	Pikesville, MD	SWIFT WATER RESCUES NEAR PIKESVILLE.

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, 0.8 hours before the alert went out and 85 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: 416 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 459 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 111 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KLWX 271249
FFWLWX
MDC005-271545-
/O.NEW.KLWX.FF.W.0021.080927T1249Z-080927T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
849 AM EDT SAT SEP 27 2008

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BALTIMORE COUNTY IN NORTHERN MARYLAND

* UNTIL 1145 AM EDT

* AT 844 AM EDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED FLASH     
  FLOODING FROM A THUNDERSTORM NEAR PIKESVILLE. THE HEAVY RAINFALL   
  IS MOVING NORTHWARD TOWARD REISTERSTOWN AND BUTLER.

* SOME LOCATIONS THAT WILL CONTINUE TO BE AFFECTED BY THE HEAVY      
  RAIN INCLUDE REISTERSTOWN AND BUTLER.

ADDITIONAL RAINFALL AMOUNTS OF ONE TO TWO INCHES ARE POSSIBLE IN THE 
WARNED AREA.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

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.

LAT...LON 3937 7664 3937 7673 3953 7686 3972 7679
      3972 7670

$$

ROGOWSKI

2 follow-up statements

000 
WGUS71 KLWX 271326
FFSLWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
926 AM EDT SAT SEP 27 2008

MDC005-271545-
/O.CON.KLWX.FF.W.0021.000000T0000Z-080927T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BALTIMORE MD-
926 AM EDT SAT SEP 27 2008

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 AM EDT FOR
NORTHWESTERN BALTIMORE COUNTY...

LOCAL LAW ENFORCEMENT OFFICIALS REPORTED SEVERAL WATER RESCUES 
EARLIER THIS MORNING RESULTING FROM A BRIEF HEAVY RAINFALL AS 
THUNDERSTORMS MOVED NORTHWARD ACROSS THE PIKESVILLE AREA. THESE 
STORMS ARE ABOUT 15 MILES NORTHEAST OF WESTMINSTER AS OF 925 
AM...AND CONTINUE TO MOVE NORTH AT 21 MPH TOWARD PENNSYLVANIA. 
ANOTHER INCH OF RAINFALL MAY OCCUR ACROSS NORTHERN BALTIMORE COUNTY 
THIS MORNING.

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.

LAT...LON 3937 7664 3937 7673 3953 7686 3972 7679
      3972 7670

$$

ROGOWSKI

000 
WGUS71 KLWX 271442
FFSLWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1042 AM EDT SAT SEP 27 2008

MDC005-271452-
/O.CAN.KLWX.FF.W.0021.000000T0000Z-080927T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BALTIMORE MD-
1042 AM EDT SAT SEP 27 2008

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHWESTERN
BALTIMORE COUNTY...

EMERGENCY MANAGEMENT OFFICIALS REPORT NO FURTHER PROBLEMS DUE TO THE 
HEAVY RAINFALL EARLIER THIS MORNING...THEREFORE THE FLASH FLOOD 
WARNING HAS BEEN CANCELLED.

LAT...LON 3937 7664 3937 7673 3953 7686 3972 7679
      3972 7670

$$

ROGOWSKI

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 27, 3:38 PM EDT	Flash Flood Warning	LWX	Baltimore, City of Baltimore	3 hr
Sep 27, 6:37 PM EDT	Areal Flood Warning	LWX	Baltimore	3 hr

Nearby

Flash Flood Warnings in Maryland, 2008 Every flash flood warning in 2008

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.