Flash Flood Warning 27, NWS Baltimore/Washington

Issued

Aug 7, 2000, 8:21 PM EDT (00:21 UTC)

Expired

Aug 7, 2000, 10:15 PM EDT

In force

114 min

Issued by

NWS Baltimore/Washington

Area

Whole counties; the outline is the Mesonet’s reconstruction

County Loudoun County, VA

The Sterling radar (KLWX), 19 km from the middle of the area, began a volume at 00:21 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.

000 
WGUS51 KLWX 080026
FFWLWX
VAC107-080215-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE-WASHINGTON
821 PM EDT MON AUG 7 2000

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHERN AND EASTERN LOUDOUN COUNTY IN NORTHERN VIRGINIA

* UNTIL 1015 PM EDT

* AT 811 PM EDT...WEATHER SERVICE DOPPLER RADAR SHOWED SHOWERS AND
  THUNDERSTORMS WITH TORRENTIAL RAINS REPEATEDLY AFFECTING SOUTHERN
  AND EASTERN LOUDOUN COUNTY. RADAR RAINFALL ESTIMATES INDICATE
  RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR. THE THUNDERSTORMS
  WERE MOVING EAST AT AROUND 25 MPH BUT NEW STORMS WERE DEVELOPING
  BACK ACROSS THE COUNTY. AT 815 PM ROAD FLOODING WAS REPORTED IN THE
  MIDDLEBURG AREA.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS. IF FLASH FLOODING IS OBSERVED ACT
QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. QUICKLY
MOVE OUT OF AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

IF WATER IS FLOWING ACROSS A ROADWAY TURN YOUR VEHICLE AROUND AND
FIND AN ALTERNATE ROUTE. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW
YOUR CAR TO CROSS SAFELY. VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY. MOVE TO HIGHER GROUND.

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. IF YOUR VEHICLE STALLS, ABANDON IT IMMEDIATELY AND SEEK
HIGHER GROUND.

TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN STERLING VIRGINIA.

LAT...LON 3912 7778 3894 7777 3899 7753 3912 7751

JLW/BMW/ABW

NWS Baltimore/Washington wrote its last area forecast discussion before this flash flood warning went out at Aug 7, 3:00 PM EDT, 5 hours 21 minutes earlier.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
300 PM EDT MON AUG 7 2000

KLWX RADAR SHOWING WIDELY SCATTERED THUNDERSTORMS DEVELOPING OVER THE
WV PANHANDLE AND ACROSS NORTHERN MD.  AMS AT TIME IS RATHER UNSTABLE
WITH 18Z LAPS INDICATING CAPE VALUES BETWEEN 3000 AND 4000 J/KG.  NO
FOCUS MECHANISM SHOWING UP ON CB-LAPS PLOT... BUT TROF ALONG THE
LEESSIDE OF APPALACHIANS MAY BE WHAT'S CAUSING THE DEVELOPING OVER OUR
NRN CWA.  EXPECTING SCATTERED SHOWERS AND STORMS TO CONTINUE INTO THE
EVENING HOURS... MAINLY ALONG AND TO THE EAST OF THE BLUE RIDGE. DEGREE
OF INSTABILITY WOULD SUGGEST THAT ISOLATED SEVERE STORMS ARE POSSIBLE..
AND WILL HAVE TO MONITOR.

FFA IN EFFECT THROUGH 800 PM FOR THE NW 1/4 OF CWA. AT TIME... AREAL
COVERAGE OF PRECIP SUGGESTS THAT OVERALL FLOODING THREAT IS MINIMAL. AT
TIME.. PLAN TO CANCEL FFA WITH AFTERNOON ZONE ISSUANCE... BUT WILL BASE
FINAL DECISION ON RADAR AND SATELLITE IMAGES OVER THE NEXT HOUR.

NO REAL WEATHER MAKER ACROSS OUR AREA FOR THE NEXT 36 HOURS. W/SW FLOW
SFC AND ALOFT WILL KEEP A VERY WARM AMS OVER THE AREA.. BUT BOTH
ETA/NGM HINTING AT WINDS TURNING A BIT MORE WESTERLY TOMORROW RESULTING
IN DEW POINTS DROPPING BACK 4 OR 5 DEGREES.  FORECAST HEAT INDEX VALUES
WILL BE AROUND 100..DEPENDING ON HOW FAR DEW POINTS DROP. WILL ISSUE
SPS WITH AFTERNOON PACKAGE HIGHLIGHTING WARM TEMPS ON TAP FOR TUESDAY.

MODEL SOUNDINGS INDICATE WARMER LOW LEVEL TEMPS ACROSS THE AREA
TOMORROW.. AND SUGGEST THAT WE MAY END UP BEING CAPPED. WILL TAKE OUT
MENTION OF PRECIP FOR TOMORROW AFTERNOON FOR THAT REASON. SHORT WAVE
MOVING THROUGH THE AREA TUESDAY NIGHT ALONG WITH A WEAK SURFACE
REFLECTION.. SO WILL KEEP CHANCE POPS IN THE AREA FOR PERIODS 3 AND 4.

FWC/FAN TEMPS HAVE BEEN RUNNING A BIT HIGH THE PAST FEW RUNS... AND
TODAY SEEMS TO BE A CONTINUATION OF THIS TREND. DEFINITELY A WARM DAY
ON TAP.. BUT PREFER 90 TgO 95 OVER MID 90S.

.LWX...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.

MARGRAF!

Flash Flood Warnings in Virginia, 2000Every flash flood warning in 2000

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.