Site Information for SLVM2 in Nws Headquarters, MD, United States of America

The following information is known about SLVM2. If you think that any information is incorrect, then please follow the instructions for correcting that data item.

It is possible that this page will report a problem where no problem exists. If you believe that this has happened, then please contact me (address at the bottom of this page) and explain clearly why you think this page is in error. Note that any changes that you make may take a few days to show up here, so please give it a week before commenting.

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Registered Location

Latitude: 38° 59' 38" N (deg min sec), 38.9939° (decimal), 3859.63N (LORAN)
Longitude: 77° 1' 53" W (deg min sec), -77.0314° (decimal), 07701.88W (LORAN)
Elevation: 275 metres (901 feet)
Location: Nws Headquarters, MD, United States of America
County: Montgomery, MD
Forecast Office: Baltimore/Washington (LWX)

The elevation does not correspond with the estimated elevation (93 metres (304 feet) -- source NED 1/9th arc-second: Washington DC) at that point. It seems probable that the elevation was entered as feet rather than as metres. Please use the 'send the updated information' link below to update the location or elevation.

The site location should be at the mark shown -- or very close. Clicking within the map area (or you can drag the 'SLVM2' marker) will display the latitude/longitude of that point.

If the displayed location (or elevation) of the weather observing location is incorrect, please drag the marker to the right location (or click in the right location), and then send the updated information. Please note that we are trying to spot either the Stevenson Screen (or equivalent) or the location where the barometric readings are taken.

Can you help with location quality? Please indicate if the marker on the map points at the weather instrument cluster:

The best way to get elevation is to consult a topographic map. Make sure that you know whether the contours are marked in feet or metres. Note that handheld GPS receivers do not provide readings of elevation accurate to better than 10-20 metres (technical discussion). If you do not have access to a topographic map, then a GPS receiver is acceptable, but make sure that it is operating in 3D mode and let it average the position for at least five minutes.

For more information on reading maps, please see the Topo Map Reading Guide -- in particular it discusses how to read contours.

The location information for this site was gathered from 1 data source. The source which most closely matches the consensus is chosen. Many of these sources only report the location to the nearest minute (or hundredth of degree). This can lead to the marker being placed noticeably incorrectly. Please see Discussion of Location Errors for more information. Show location history.

There are no photographs of the station. If you have pictures of this location, then please email them to

You can try to find photographs from the area surrounding the site marker by clicking on Find nearby photographs.

Neighboring Stations

This is a list of stations that are close to this station.

You can also subscribe to an RSS feed to tell you when new stations come online in this area. Choose either within 100 miles or 250 miles . For stations covered by your Forecast Office: Baltimore/Washington (LWX) .

DW94210.8 milesNorth Silver Spring, MD, US (lat 39.0060°, long -77.0328°, altitude 106 metres) (data present)
DW44412.3 milesSoutheast Takoma Park, MD, US (lat 38.9785°, long -76.9941°, altitude 53 metres) (data present)
DW62793.9 milesSouthwest Chevy Chase, MD, US (lat 38.9662°, long -77.0947°, altitude 98 metres) (data present)
EW28094.0 milesNortheast White Oak, MD, US (lat 39.0450°, long -76.9950°, altitude 121 metres) (data present)
EW53094.2 milesNorthwest Kensington, MD, US (lat 39.0403°, long -77.0830°, altitude 93 metres) (data present)
EW31605.7 milesSouthwest Brookmont, MD, US (lat 38.9530°, long -77.1225°, altitude 89 metres) (data present)
KCGS5.9 milesEast College Park AP, College Park, MD, United States of America (lat 38.9806°, long -76.9223°, altitude 15 metres) (data present)
EW55486.7 milesSouth Washington, DC, US (lat 38.9000°, long -77.0000°, altitude 2 metres) (data present)
CW97346.9 milesWest West Bethesda, MD, US (lat 39.0039°, long -77.1584°, altitude 75 metres) (data present)
DW80168.4 milesSouthwest Arlington, VA, US (lat 38.9063°, long -77.1385°, altitude 97 metres) (data present)

The sites marked above thus did not report continuously during the analysis period, so the offsets may (probably will) not be accurate.

Location Formats

The location is shown in three different formats. Each of these is used in some software, and is shown on some websites.

Degrees Minutes Seconds: VWS/VWSAPRS, WeatherLink 5.5, WeatherLink (5.2-5.4), WeatherView (Linux)

Decimal degrees: FreeWX, WeatherView32 (PC application)

LORAN: WeatherDisplay, WUHU, Henriksen WServer


CWOP Home: This describes the whole CWOP program and has a large amount of useful information.

CWOP Siting Guide (PDF): This is a guide to siting and operating a CWOP station. This is a must-read document.

Another CWOP Guide (PDF): This is another guide to siting and operating a CWOP station. This is a must-read document.

Urban Siting and Operations (PDF): This is a guide to siting and operating a CWOP station in an urban environment.

APRS WX Message format: This describes the actual format of the messages transmitted that carry WX information.

WXQC Mailing List: This is a mailing list where data quality issues are discussed. Assistance with software configuration can often be found here.

Topo Map Reading Guide: How to read USGS topographic maps, with a good section on reading contours.

Geographically nearby web pages: Use Geourl to find web pages that deal with locations geographically close to this site.

Overall website comments, problems etc to Philip Gladstone
Page layout last modified Sunday, 16 November 2014
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