Alert archive / Virginia / Flash Flood Warnings in 2014

Flash Flood Warning 21, NWS Baltimore/Washington

June 12, 2014Loudoun County, Virginia; Frederick County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jun 12, 2014, 3:24 PM EDT for Loudoun County, Virginia; Frederick 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
Jun 12, 2014, 3:24 PM EDT (19:24 UTC)
Expired
Jun 12, 2014, 6:30 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

Counties Frederick County, MD, Loudoun County, VA

The radar

The Sterling radar (KLWX), 31 km from the middle of the area, began a volume at 19:27 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 12, 3:42 PM EDTFLASH FLOOD2 Nw Leesburg, VAEAST BOUND ROUTE 7 CLOSED AT WEST MARKET STREET DUE TO HIGH WATER
Jun 12, 4:01 PM EDTFLASH FLOOD1 Se Paeonian Springs, VAWATER 6-8 INCHES FLOWING OVER BRIDGEVIEW COURT NEAR THE INTERSECTION OF ROUTE 7 AND ROUTE 9
Jun 12, 5:00 PM EDTFLASH FLOOD2 Wnw Leesburg, VAPORTION OF DRY MILL ROAD BETWEEN WOODBURN AND CAMBY ROADS WASHED AWAY NEAR GOOSE CREEK
Jun 12, 5:00 PM EDTFLASH FLOOD2 Wnw Leesburg, VAPORTION OF DRY MILL ROAD BETWEEN WOODBURN AND THOMAS MILL ROADS WASHED AWAY NEAR GOOSE CREEK

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, 7.4 hours before the alert went out and 37 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 2014-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 195 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 2014-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
195 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
537 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

361 
WGUS51 KLWX 121924
FFWLWX
MDC021-VAC107-122230-
/O.NEW.KLWX.FF.W.0021.140612T1924Z-140612T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
324 PM EDT THU JUN 12 2014

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN FREDERICK COUNTY IN NORTH CENTRAL MARYLAND...
  CENTRAL LOUDOUN COUNTY IN NORTHERN VIRGINIA...

* UNTIL 630 PM EDT

* AT 318 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN CAPABLE OF PRODUCING FLASH FLOODING. RADAR
  ESTIMATES THAT UP TO 1 INCH OF RAIN HAVE ALREADY FALLEN ACROSS
  PORTIONS OF THE WARNED AREA. ADDITIONAL RAINFALL AMOUNTS OF UP TO 2
  INCHES CAN BE EXPECTED.

* SOME LOCATIONS THAT ARE AFFECTED BY THE HEAVY RAIN INCLUDE
  LEESBURG...BRUNSWICK AND POINT OF ROCKS.

THIS INCLUDES THE FOLLOWING STREAMS AND DRAINAGES...
CATOCTIN CREEK...BROAD RUN...POTOMAC RIVER...DUTCHMAN CREEK...SOUTH
FORK CATOCTIN CREEK...GOOSE CREEK...NORTH FORK GOOSE CREEK...
BEAVERDAM CREEK...SOUTH FORK SYCOLIN CREEK...BIG BRANCH...SYCOLIN
CREEK...QUARTER BRANCH...TUSCARORA CREEK...CROOKED RUN...LIMESTONE
BRANCH AND NORTH FORK CATOCTIN CREEK.

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

LAT...LON 3935 7750 3902 7754 3903 7770 3936 7766
      3937 7765

$$
1 follow-up statement
931 
WGUS71 KLWX 122020
FFSLWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
420 PM EDT THU JUN 12 2014

MDC021-VAC107-122230-
/O.CON.KLWX.FF.W.0021.000000T0000Z-140612T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FREDERICK MD-LOUDOUN VA-
420 PM EDT THU JUN 12 2014

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM EDT FOR
CENTRAL LOUDOUN AND SOUTHWESTERN FREDERICK COUNTIES...

AT 415 PM EDT...EMERGENCY MANAGEMENT REPORTED ROAD CLOSURES DUE TO 
FLASH FLOODING FROM VERY HEAVY RAIN. ADDITIONAL RAINFALL AMOUNTS OF 
UP TO 1 INCH ARE POSSIBLE.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LEESBURG...
BRUNSWICK...POINT OF ROCKS AND OATLANDS.

THIS INCLUDES THE FOLLOWING STREAMS AND DRAINAGES...
CATOCTIN CREEK...BROAD RUN...POTOMAC RIVER...DUTCHMAN CREEK...SOUTH
FORK CATOCTIN CREEK...GOOSE CREEK...NORTH FORK GOOSE CREEK...
BEAVERDAM CREEK...SOUTH FORK SYCOLIN CREEK...BIG BRANCH...SYCOLIN
CREEK...QUARTER BRANCH...TUSCARORA CREEK...CROOKED RUN...LIMESTONE
BRANCH AND NORTH FORK CATOCTIN CREEK.

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

LAT...LON 3935 7750 3902 7754 3903 7770 3936 7766
      3937 7765

$$

DH

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 11, 8:03 PM EDTSpecial Marine WarningLWX57 min
Jun 11, 8:46 PM EDTSevere Thunderstorm WarningLWXFairfax, Loudoun, City of Falls Church33 min
Jun 11, 9:39 PM EDTFlash Flood WarningLWXLoudoun3 hr
Jun 11, 10:05 PM EDTCoastal Flood AdvisoryLWXArlington, City of Alexandria, City of Falls Church12 hr
Jun 11, 11:57 PM EDTSpecial Marine WarningLWX93 min
Jun 12, 12:47 AM EDTAreal Flood WarningLWXLoudoun4 hr
Jun 12, 1:02 AM EDTSpecial Marine WarningLWX88 min
Jun 12, 1:46 AM EDTSmall Craft AdvisoryLWX6 hr
Jun 12, 3:48 AM EDTFlash Flood WatchLWXArlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 12 more20 hr
Jun 12, 6:52 AM EDTSmall Craft AdvisoryLWX14 hr
Jun 12, 3:55 PM EDTFlash Flood WarningLWXLoudoun3 hr
Jun 12, 5:09 PM EDTCoastal Flood AdvisoryLWXArlington, Fairfax, King George, Stafford, City of Alexandria, City of Fairfax and 1 more18 hr
Jun 12, 6:25 PM EDTAreal Flood WarningLWXLoudoun13 hr
Jun 12, 6:28 PM EDTFlash Flood WarningLWXGreene, Madison3 hr
Jun 11, 9:32 PM EDTFlash Flood WarningLWXMontgomery3 hr
Jun 11, 9:35 PM EDTFlash Flood WarningLWXWashington3 hr
Jun 12, 3:03 PM EDTFlash Flood WarningLWXWashington7 hr
Jun 12, 4:15 PM EDTFlash Flood WarningLWXFrederick, Washington3 hr
Jun 12, 6:32 PM EDTFlash Flood WarningLWXAllegany6 hr

Nearby

Flash Flood Warnings in Virginia, 2014Flash Flood Warnings in Maryland, 2014Every flash flood warning in 2014

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.