Alert archive / Maryland / Flash Flood Warnings in 2017

Flash Flood Warning 21, NWS Baltimore/Washington

July 23, 2017Harford County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jul 23, 2017, 7:05 PM EDT for Harford County, Maryland. It was in force for 3 hr. 4 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
Jul 23, 2017, 7:05 PM EDT (23:05 UTC)
Expired
Jul 23, 2017, 10:00 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

County Harford County, MD

The radar

The Dover AFB radar (KDOX), 109 km from the middle of the area, began a volume at 23:06 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
Jul 23, 7:45 PM EDTFLASH FLOOD1 N Havre De Grace, MDSUPERIOR STREET CLOSED AT NORTH JUNIATA STREET DUE TO HIGH WATER.
Jul 23, 7:45 PM EDTFLASH FLOOD1 Nnw Havre De Grace, MD800 BLOCK OF TYDINGS ROAD CLOSED DUE TO HIGH WATER.
Jul 23, 7:45 PM EDTFLASH FLOODHavre De Grace, MDNORTH JUNIATA STREET CLOSED AT OTSEGO STREET DUE TO HIGH WATER.
Jul 23, 7:45 PM EDTFLASH FLOODHavre De Grace, MDREVOLUTION STREET CLOSED DUE TO HIGH WATER BETWEEN LEWIS LANE AND SOUTH JUNIATA STREET.

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, 11.1 hours before the alert went out and 129 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 2017-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 186 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, Washington/Dulle, VA at 12:00Z on 2017-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 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
186 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
983 m above ground
0-6 km bulk shear
21 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
0.1

Open this sounding in Storm Lab

The text

As transmitted.

899 
WGUS51 KLWX 232305
FFWLWX
MDC025-240200-
/O.NEW.KLWX.FF.W.0021.170723T2305Z-170724T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
705 PM EDT SUN JUL 23 2017

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  Northeastern Harford County in northern Maryland...

* Until 1000 PM EDT

* At 704 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the area. Up to 3.5 inches of rain have already 
  fallen. Additional rainfall amounts of 1 to 2 inches are possible. 
  Flash flooding is expected to begin shortly.

* Some locations that may experience flooding include...
  Havre De Grace, Darlington, Cardiff and Scarboro. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3968 7620 3965 7616 3962 7615 3959 7611
      3954 7608 3953 7610 3958 7612 3955 7618
      3957 7627 3972 7635 3972 7623

$$

ADS
2 follow-up statements
501 
WGUS71 KLWX 240026
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
826 PM EDT SUN JUL 23 2017

MDC025-240200-
/O.CON.KLWX.FF.W.0021.000000T0000Z-170724T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harford MD-
826 PM EDT SUN JUL 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 PM EDT FOR
NORTHEASTERN HARFORD COUNTY...

At 824 PM EDT, doppler radar indicated heavy rain had exited the 
area. However, three to five inches of rain have fallen. Flash 
flooding has been reported in the Havre de Grace area, with several 
roads closed.

Some locations that will experience flooding include...
Havre de Grace and Darlington. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3971 7623 3962 7615 3959 7611 3954 7608
      3953 7610 3958 7612 3955 7618 3972 7630
      3972 7623

$$

ADS
598 
WGUS71 KLWX 240041
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
841 PM EDT SUN JUL 23 2017

MDC025-240047-
/O.CAN.KLWX.FF.W.0021.000000T0000Z-170724T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harford MD-
841 PM EDT SUN JUL 23 2017

...THE FLASH FLOOD WARNING FOR NORTHEASTERN HARFORD COUNTY IS
CANCELLED...

Havre de Grace Police has reported that streets are re-opened after 
previous flooding. The threat of rapid rises of water and life 
threatening flooding has ended, and thus the Flash Flood Warning is 
cancelled. However, some high water likely still exists after three 
to five inches of rainfall, ans small streams will remain near or 
over bankfull. Thus, a Flood Warning remains in effect.

LAT...LON 3971 7623 3962 7615 3959 7611 3954 7608
      3953 7610 3958 7612 3955 7618 3972 7630
      3972 7623

$$

ADS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 3:06 PM EDTSevere Thunderstorm WarningLWXHarford39 min
Jul 23, 3:44 PM EDTSevere Thunderstorm WarningLWXHarford14 min
Jul 23, 4:59 PM EDTFlash Flood WatchLWXAnne Arundel, Baltimore, Carroll, Frederick, Harford, Howard and 3 more9 hr
Jul 23, 5:01 PM EDTAreal Flood WarningLWXMontgomery, Prince George's4 hr
Jul 23, 5:19 PM EDTFlash Flood WarningLWXHarford3 hr
Jul 23, 5:45 PM EDTAreal Flood WarningLWXHarford5 hr
Jul 23, 7:10 PM EDTAreal Flood WarningLWXBaltimore, Harford4 hr
Jul 23, 7:55 PM EDTAreal Flood WarningLWXHarford9 hr

Nearby

Flash Flood Warnings in Maryland, 2017Every flash flood warning in 2017

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.