Alert archive / Virginia / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 49, NWS Baltimore/Washington

May 27, 2001Fairfax County, Loudoun County, Virginia; Montgomery County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at May 27, 2001, 2:25 PM EDT for Fairfax County, Loudoun County, Virginia; Montgomery County, Maryland. It was in force for 50 min. 5 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
May 27, 2001, 2:25 PM EDT (18:25 UTC)
Expired
May 27, 2001, 3:15 PM EDT
In force
50 min
Issued by
NWS Baltimore/Washington
Area
Whole counties

Counties Montgomery County, MD, Fairfax County, VA, Loudoun County, VA

The radar

The Sterling radar (KLWX), 11 km from the middle of the area, began a volume at 18:37 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
May 27, 2:34 PM EDTThunderstorm WindSterling, VALarge trees were downed between Algonkian Parkway and Countryside Boulevard.
May 27, 2:57 PM EDTHail 0.75Montgomery Vlg, MDDime sized hail was reported.
May 27, 3:00 PM EDTThunderstorm WindGreat Falls, VATrees were snapped.
May 27, 3:10 PM EDTTornado F1Olney, MDNumerous trees were downed and buildings were damaged.
May 27, 3:12 PM EDTThunderstorm WindOlney, MDA few trees were downed.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 27, 1:45 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.4 hours before the alert went out and 8 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 2001-05-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 49 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2001-05-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 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
49 J/kg
Mixed-layer CIN
-99 J/kg
Mixed-layer LCL
728 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
74 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.

753 
WUUS51 KLWX 271826
SVRLWX
MDC031-VAC059-107-271915-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BALTIMORE-WASHINGTON
225 PM EDT SUN MAY 27 2001

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MONTGOMERY COUNTY IN CENTRAL MARYLAND
  FAIRFAX COUNTY IN NORTHERN VIRGINIA
  LOUDOUN COUNTY IN NORTHERN VIRGINIA

* UNTIL 315 PM EDT

* AT 224 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
SEVERE THUNDERSTORM OVER ASHBURN...MOVING EAST AT 35 MPH.  THIS 
STORM WILL BE MOVING ACROSS THE REMAINDER OF EASTERN LOUDOUN 
COUNTY...NORTHERN FAIRFAX COUNTY AND MONTGOMERY COUNTY. 

* THE SEVERE THUNDERSTORM WILL BE...
  3 MILES NORTH OF COUNTRYSIDE AT 230 PM
  OVER NORTH POTOMAC AT 244 PM
  3 MILES SOUTH OF GAITHERSBURG AT 246 PM
  OVER ROCKVILLE AT 250 PM
  OVER ASPEN HILL...3 MILES SOUTH OF OLNEY AT 258 PM

REMEMBER...A SEVERE THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...
DAMAGING WINDS IN EXCESS OF 55 MPH...DEADLY LIGHTNING...AND VERY
HEAVY RAIN. IF SEVERE WEATHER APPROACHES...GO INSIDE A STURDY SHELTER
AND STAY AWAY FROM DOORS AND WINDOWS.

TUNE INTO NOAA WEATHER RADIO OR YOUR LOCAL RADIO OR TV STATION FOR
THE LATEST WEATHER INFORMATION.

$$
JMM/MKM

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Baltimore/Washington wrote its last area forecast discussion before this severe thunderstorm warning went out at May 27, 10:00 AM EDT, 4 hours 25 minutes earlier.

Area forecast discussion, May 27, 10:00 AM EDT, 4 hours 25 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1000 AM EDT SUN MAY 27 2001

A LINE OF SHOWERS ASSOCIATED WITH THE STRONG SHORTWAVE IS CURRENTLY
SWING THROUGH WV. AS IT MOVES IN TO VA AND MD IT WILL ENCOUNTER
INCREASING UNSTABLE CONDITIONS. (SEE SWODY1) HAVE ISSUED SWO FOR
THIS AFTERNOON. WILL UPDATED FIRST PD FOR STRONGER WORDING FOR
TSTMS. WILL ALSO ADD SOME POPS IN TONIGHT FOR THE NE ZONES.

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

ND

In the hours before

Special weather statement, May 27, 9:55 AM EDT, 4 hours 30 minutes before
DCZ001-MDZ003>007-009>011-013-014-VAZ042-053-054-WVZ051>053-272300-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE-WASHINGTON
955 AM EDT SUN MAY 27 2001

...SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE DISTRICT OF
COLUMBIA...MARYLAND EAST OF WASHINGTON COUNTY TO THE CHESAPEAKE
BAY...THE EXTREME NORTHEAST SECTION OF VIRGINIA...AND MORGAN
...BERKELEY...AND JEFFERSON COUNTIES IN THE EASTERN WEST VIRGINIA
PANHANDLE.

THE LARGE AREA OF LOW PRESSURE WHICH HAS BEEN STATIONARY OVER
SOUTHERN MICHIGAN FOR THE PAST FEW DAYS WILL SLOWLY DRIFT TOWARD
OUR REGION LATER TODAY AND TONIGHT. AS THE LOW MOVES CLOSER A STRONG
DISTURBANCE WILL ROTATE AROUND THE LOW AND WILL PROVIDE THE FOCUS
FOR THUNDERSTORMS ACROSS REGION.

THUNDERSTORMS WILL DEVELOP TODAY IN THE MOUNTAINS...AND SPREAD
EASTWARD THIS AFTERNOON. THE THUNDERSTORMS WILL CONTINUE INTO THE
EVENING HOURS...ESPECIALLY IN THE WASHINGTON-BALTIMORE
METROPOLITAN AREA. STRONG WIND GUSTS...IN EXCESS OF 60 MPH AND HAIL
GREATER THAN THREE-QUARTERS OF AN INCH IN DIAMETER WILL BE THE MAJOR
THREATS FROM THESE THUNDERSTORMS.

THESE STORMS WILL ALSO PRODUCE AREAS OF HEAVY RAIN...RESULTING IN
RAPID RISES ON CREEKS AND SMALLER RIVERS.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT
HTTP://WWW.NWS.NOAA.GOV/ER/LWX

The office that day

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

IssuedProductOfficeCountiesLasted
May 26, 8:13 PM EDTFlash Flood WarningLWXFrederick, City of Winchester2 hr
May 26, 8:26 PM EDTFlash Flood WarningLWXShenandoah2 hr
May 26, 8:58 PM EDTSevere Thunderstorm WarningLWXClarke32 min
May 26, 10:19 PM EDTFlash Flood WarningLWXFrederick3 hr
May 27, 1:05 PM EDTSevere Thunderstorm WarningLWXClarke, Frederick40 min
May 27, 1:05 PM EDTSevere Thunderstorm WarningLWXShenandoah, Warren40 min
May 27, 1:05 PM EDTSevere Thunderstorm WarningLWXCity of Winchester40 min
May 27, 1:31 PM EDTTornado WarningLWXClarke, Warren29 min
May 27, 1:50 PM EDTSevere Thunderstorm WarningLWXClarke, Fauquier, Loudoun40 min
May 27, 2:35 PM EDTSevere Thunderstorm WarningLWXPrince William, City of Manassas, City of Manassas Park40 min
May 27, 2:35 PM EDTSevere Thunderstorm WarningLWXFauquier40 min
May 27, 3:02 PM EDTSevere Thunderstorm WarningLWXHoward43 min
May 27, 3:08 PM EDTSevere Thunderstorm WarningLWXPrince George's37 min
May 27, 3:17 PM EDTSevere Thunderstorm WarningLWXMontgomery28 min
May 27, 3:26 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, City of Baltimore49 min
May 27, 6:53 PM EDTSevere Thunderstorm WarningLWXMontgomery52 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2001Severe Thunderstorm Warnings in Maryland, 2001Every severe thunderstorm warning in 2001

Sources

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