CWOP Information for DW9420 (D9420) in New Gretna, NJ, US

The following information is known about DW9420. 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.

Location Map: If this message persists, then your browser is not compatible with Google Maps.
  Larger  Smaller  Google Earth.

Registered Location

Latitude: 39° 35' 11" N (deg min sec), 39.5865° (decimal), 3935.19N (LORAN)
Longitude: 74° 27' 49" W (deg min sec), -74.4637° (decimal), 07427.82W (LORAN)
Elevation: 25 metres (82 feet) -- validated against 2 metres (8 feet) from NED 1/9th arc-second: Camden New Jersey
Location: New Gretna, NJ, US
County: Burlington, NJ
Forecast Office: Philadelphia/Mt Holly (PHI)
Weather station Manager/Operator: Lee
Station type/software: WeatherSnoop / WMR200

The site location should be at the mark shown -- or very close. Clicking within the map area (or you can drag the 'DW9420' 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.

NOTE: The Registered Location is the location that the station owner provided when they signed up with CWOP. Show location history.

There are no photographs of the station. If you are the site operator and 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.

Data Status

Over the last 28 days, no data was seen on the following dates: 2017-08-26 to 2017-08-29, 2017-08-31 to 2017-09-03, 2017-09-05 to 2017-09-06, 2017-09-08 to 2017-09-15, 2017-09-17 to 2017-09-20.

A reasonably recent weather report (5 days ago) received from this station was

All the means and standard deviations shown below are from the last 28 days. Change analysis period to Last 3 days  Last 7 days  Last 14 days  Last 8 weeks  Last 13 weeks  Last 26 weeks  Last 39 weeks  Last 52 weeks  

A recently received weather report from this station was


Average barometer error: -2.1 milliBars
Error standard deviation: 0.7 milliBars
Mean error value of -2.1 exceeds limit of 2.0
MADIS rating 36% QC OK
Sensor fails following checks:
L2 Statistical Spatial Consistency
L3 Spatial Consistency

Latest daily graph:

Latest daily graph

There is a significant mean error in your barometer readings. You may need to calibrate your barometer.


  24 hours  Day time  Night time
Average temperature error-7.0 °F-5.9 °F-24.5 °F
Error standard deviation6.4 °F5.2 °F0.0 °F
Worst average temperature error-1.0 °F-1.0 °F-1.0 °F
Worst standard deviation0.0 °F0.0 °F0.0 °F

NOTE: If the error above is POSITIVE, then it means that the analysis temperature is HIGHER than the reported temperature. This means that your sensor is reading COLDER than expected.

  Both day (mean error -5.9, sd 5.2) and night (mean error -24.5, sd 0.0) values out of range
MADIS rating 63% QC OK
Sensor fails following checks:
L3 Spatial Consistency

Latest daily graph:

Latest daily graph

The values returned by your sensor indicate a system problem. This can be caused by a 'stuck' sensor that always reports the same value. Please check your station for proper operation.

Dewpoint -- or switch to Relative Humidity

  24 hours  Day time  Night time
Average dewpoint error1.5 °F3.6 °F-3.5 °F
Error standard deviation5.1 °F4.1 °F0.0 °F
Worst average dewpoint error-1.0 °F-1.0 °F-1.0 °F
Worst standard deviation0.0 °F0.0 °F0.0 °F

NOTE: If the error above is POSITIVE, then it means that the analysis temperature is HIGHER than the reported temperature. This means that your sensor is reading COLDER than expected.

  Temperature problem
MADIS rating 85% QC OK

Latest daily graph:

Latest daily graph

The mean error of your daytime readings is significantly different to the mean error of your nighttime readings. In particular, the difference is -7.1 °F warmer during the day. This is indicative of a solar heating problem. This is often caused by the lack of a radiation shield, or the sensor is poorly sited. For information on radiation shields, see CWOP Radiation Shields, and information on siting, see CWOP Station Guide.

Wind Vector

The wind vector is the average wind over the relevant period. Note that if the wind blows North for half the time at 2 knots, and then blows South for the other half of the time at 2 knots, then the result is zero -- i.e. North wind and South wind will cancel out. Over time, the direction of the wind and of the analysis should match pretty well. If the lengths of the vector are different, then it could mean either that your anemometer reads high or low, or that you are in a more shielded or more open space.
MADIS rating 100% QC OK
TodayLast 7 days
Wind vector chartWind vector chart for last 7 days

Neighboring Stations

This is a list of stations that are close to this station. Note that this is not the list of stations that are used in the data analysis. That list of stations is known only to MADIS. You can see all the stations at MADIS Data Display. Your station should be in the middle of the display. If you think that the analysis is incorrect, then maybe one of the close stations has failed.

You can look at those for comparison purposes. The average difference between your station and each station below is listed as well. This may allow you to detect local stations which are erroneous. You can also use these numbers to adjust your instruments -- especially if a number of ASOS stations have similar differences to your station. Also, try increasing the analysis period to more than the default 28 days. The difference is only given if both stations report reasonably often during each day. Some stations only report every 6 hours, and this makes the average of less interest. In this case, the average is not displayed. The values reported are the differences between this station and the neighboring station. I.e. if the difference is positive, then this station is reading higher than the neighboring station. Since this station has not been reporting continuously during the analysis period (it missed 22 days out of 28), the offsets below may not be accurate.

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: Philadelphia/Mt Holly (PHI) .

KACY10.8 milesSouthwest ATLANTIC CITY INTERNATIONAL, NJ, United States (lat 39.4520°, long -74.5670°, altitude 20 metres)
EW432111.5 milesEast Beach Haven, NJ, US (lat 39.5447°, long -74.2555°, altitude 2 metres)
DW856515.7 milesEast Ship Bottom, NJ, US (lat 39.6437°, long -74.1792°, altitude 5 metres)
CW881216.2 milesSouth Northfield, NJ, US (lat 39.3668°, long -74.5710°, altitude 4 metres)
EW263220.0 milesSouth Somers Point, NJ, US (lat 39.3165°, long -74.5965°, altitude 11 metres)
CW529220.7 milesNorthwest Shamong, NJ, US (lat 39.7910°, long -74.7468°, altitude 23 metres)
EW618821.6 milesNortheast Waretown, NJ, US (lat 39.8067°, long -74.1760°, altitude 2 metres)
KMJX25.3 milesNorth Miller Air Park, Toms River, NJ, United States of America (lat 39.9275°, long -74.2924°, altitude 25 metres)
WX2NJ-1325.7 milesNortheast Pinewald, NJ, US (lat 39.8847°, long -74.1738°, altitude 15 metres)
DW210426.9 milesNorth Whiting, NJ, US (lat 39.9672°, long -74.3603°, altitude 47 metres)

Quality Control Notes

This page reports on the quality control checks performed by MADIS. The green check mark and red cross are chosen based on the average performance during the analysis period (which is selectable above). The red cross can appear even if MADIS reports that all observations pass the MADIS QC checks.

The 'MADIS rating' reports on the percentage of observations that pass the MADIS checks. You should aim for two thumbs up!

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, 28 February 2016
Questions for this weather station owner/operator to Lee
This page is one of 86007 similar pages. This one was generated in 1.51 seconds.