July 2017 Rockville 2.8 WNW Maryland Weather Summary for the NJWO Blog

by Kevin Shaw, Observer in charge

Average high temperature 87.3°
Average low temperature 70.9°
Mean temperature 79.1°

Precipitation 8.65″
Greatest daily amount(date) 2.92″ (28)
Snow 0.0″
Year to date precipitation 26.20″

High temperature for the month (date) 94° (21)
Low temperature for the month (date) 61° (31)

Highest barometric pressure (date) 30.23” (26)
Lowest barometric pressure (date) 29.65” (29)

Peak wind gust (date/direction): N/A

Heating degree days for the month: 0
Cooling degree days for the month: 438

Greatest diurnal range (date): 26.5° (31)
Least diurnal range (date) 6.7° (6)

Number of days:

Fog 4
Thunder: 5
Cloudy 6
Partly Cloudy 16
Sunny/Clear 9
Max temp => 90° 13

by Kevin Shaw, observer in charge

July 2017 was a bit warmer than normal and definitely wetter than normal. The 8.65″ of rain this month was easily my wettest month of the year, and the 2.92″ of rain that fell on the 28th was not only the wettest day of the month, but it was easily the wettest day of the year so far. 13 days with measurable rain was a bit above average, but nothing really earth-shaking.Three of the wetter days of the month had max temps in the 70s, including the lowest of the month of 73.7° on the 29th, my 67th birthday. To me, this was better weather for my birthday than usual. Coincidentally there were also 13 days with max temps of 90° or greater, nothing unusual and certainly not related to the same amount of measurable rain days. The highest temp of the month of 93.7° was not really that high, though plenty oppressive with the usual +70° dew point temperatures all day. There were a total of 7 days where dew points remained above the 70° mark. Conversely there also were 7 days where the dew point reached down into the 50s. 5 days hit the max dew point value for the month of 78°. As has been the usual trend the past several years
stretching back to my old station, my lowest temperature for the month of 60.7° on the 31st, staying above the 60° mark all month. We used to get minimum temperatures well down into the 50s every July back several years ago, and even occasionally into the 40s.

The coolest temperatures of the month occurred right at the end of the month, after our biggest rain on the 28th and 29th. The hottest period of the month (July 11-22) was when all days had max temps above 85°, including 10 days above 90°. This period was also quite dry, totaling only 0.86″ of rain through the 21st, then a 2 day period on the 22nd and 23rd put an end to this modest heat wave/drier spell with 1.67″ of welcome rain.

There were no heating degree days (HDD) and 438 cooling degree days (CDD) during the month.

My maximum temperature frequencies included 13 days of 90° or more, 14 days between 80° and 89°, and 4 days between 70° and 79° On the minimum
temperature frequency side of things, there were 7 days between 60° and 69°, and 24 days of 70° or over.

The diurnal range daily monthly average was 16.5°. I moved my temperature sensor down to ground level at the beginning of the month, so I suspect these diurnal ranges will increase some in the coming months. The maximum daily range of 26.5° occurred on the 31st (87.2°-
60.7°). There were 5 days total with daily ranges at or above 20.0°. The lowest daily temperature range of 6.7° (78.8°- 72.1°) which occurred on the 6th interestingly enough occurred on the wettest day of the month (0.95″) till the 28th’s monster total. There were only a total of 3 days with minimum daily temperature ranges less than 10.0°.

Thankfully, the last third of the month was cooler and wetter, putting a halt on a potential drought situation which had increased to moderate levels. Major improvements to my instrument sitings have occurred recently as already mentioned. In addition, my ground-based cocorahs rain gauge site finally has been situated off property and definitely away from sprinklers. Please ask me any questions you want at any time through any means you can.

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About dabourphoto

Professional Photographer www.dabourphotography.com
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