Today (September 2014) marks the one year anniversary of collecting continuous data from a weather station located in Northern Virginia. The station is mounted atop a 10 foot wooden post to allow the wind vane minimal interference. A dark plastic disk-like cover that was previously used as a flower pot base shades the temperature sensor from having excess direct sunlight. Always consider minimizing direct exposure to the sun when positioning a weather station or temperature readings may often be too high! Reflective aluminum foil was sealed underneath the weather station's flower pot cover to minimize heat from the darker colored solid plastic.
Weather data over the last year will be detailed from the station that includes readings of temperature, humidity, and precipitation observations. The automated measurements that were collected will be compared to those of the official local weather readings for the Washington, D.C. area.
Connecting Local Weather to Washington D.C.
The following graph shows how local temperature readings (red line) compare to those recorded for Washington, D.C. (blue line). Shockingly, there appears to be relatively strong statistical correlation for maximum temperatures between the two weather stations that are located approximately eight miles apart. What should end up being the highest annual temperature of 99 degrees for 2014 was recorded on July 2 for both stations. The lowest temperatures for 2014 for both stations again fell on the same day on January 19 when temperatures never rose above 19 degrees thanks to the polar vortex strong dips in the Jet Stream into the Continental U.S.
Daily Maximum Temperature Comparison
Comfortably Uncomfortable Proximity to Saturation
Multiple factors of the state of the atmosphere determine your outdoor comfort levels. Humidity and temperature are included within these conditions. As already shown, temperatures between the D.C. airport and Virginia weather stations have little variability, but the next graphs show different results. The top relative humidity graph values for the Virginia weather station (green line) almost always exceed those that are recorded for D.C. (burgundy line). This result is surprising, because the D.C. station is located where there are likely influences from the adjacent Potomac River.
Basic meteorology principles reveal how proximity to a water body can induce cloud development, but for some unknown reason, the relative humidity values from the top graph tend to be higher in the suburban Northern Virginia location about 8 miles west of the Potomac River. The precipitation comparison lower graph between the two stations does support the water proximity idea. D.C. precipitation (orange line) tends to often exceed Virginia's precipitation (purple line) from the weather station. Saturation occurs only when humidity rises to 100%. Soon after 100% humidity is exceeded, the atmosphere reaches supersaturation and precipitation will soon form. Typically, surface relative humidity values close to 100% can indicate precipitation is on the way, if not already falling.
Daily Maximum Relative Humidity Comparison
Daily Precipitation Comparison
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