AUGUST 2019 MONTHLY SUMMARY ROCKVILLE 2.8 WNW MARYLAND
by Kevin Shaw, Observer
August 2019 was much wetter and a bit warmer than normal. My max temp
(84.5°) was only 0.3° above normal but my min temp (67.6°) was more
significantly 3.4° above normal, resulting in the mean temperature (76.0°)
to be 1.8° above normal. My total precipitation of 7.63″ was 4.44” above
the normal August value for my station of 3.19”. There were more days
but generally smaller daily amounts of precipitation than in July leading to
an about normal amount of 11 days with measurable precipitation, Nine of
those eleven days fell during two generally wet periods from August 3-7
and August 18-23 During these two periods 7.17” was recorded (over 96%
of the month’s total).
There were only one notable relatively cool periods (max temps below 80°)
during the month, a total of 6 straight days from August 23rd-29th.The
coolest August min temp of 59.4° was reached at the end of this streak
on the 30th. We didn’t have much rain during this period (0.34”) but we
did have a lot of clouds to help keep the temperatures down. Conversely,
the hottest period of the month was just prior to this cooler period, from
the 18th-20th with 3 straight days of max temps over 90, including the
month’s hottest reading of 92.2° on the 18th.
There were 11 days with measurable precipitation, highlighted by the
monthly maximum of 1.22″ on the 21st during a period of numerous
thunderstorms on the stormiest period of the month (2.53” from the
20th-23rd) Other thunderstormy periods included the 3rd-4th (1.61”)
and the 7th-8th (2.23”) Conversely there was one notably significant
dry period during August when no rain fell (7 straight days from the 8th-
14th). There was also a significantly dry period at the end of the month
(8 days from the 24th-31st) when only one day had rain (0.31” on the
28th) July had a very similar dry spell on those same last 8 days of the
month. With the generally wet month once again, these dry periods did
not start showing any adverse effects on the vegetation in the immediate
area.
The highest barometric pressure reading of the month of only 30.25”
occurred on the 25th and 31st during the end of the month dry period.
The lowest reading was 29.74” on the 7th and 8th occurred around the
time of two consecutive thunderstormy days of over an inch each day on
the 6th and 7th. This lowest reading was the same value as the lowest
reading in July.
The highest dew point temperature reached during the month was 78°
on the hottest day of the month on the 18th , a, in the middle of our
most humid period of the month with 12 straight days with dew point
temps over 70° There also was a 9 day streak of 70 or greater dew
points on the first 9 days of the month. There were 22 days in July
when dew point temps were 70° or higher, including 10 days at or
above 75°, mostly during the middle third of the month. The lowest
dew point temperature value was reached on the 24th when a value
of 52° was reached. There were 8 days during the month when the
dew point temps were in the 50s, most of which occurred during the
previously discussed coolest period of the month. .
August had 10 cloudy days, 19 partly cloudy days, and only 2 clear/
sunny days with an unusual higher amount of partly cloudy days due
to numerous thunderstorm days during the month (9 with several multi-
storm days) There were 0 heating degree days and 342 cooling degree
days during the month. There were 8 foggy days, 7 windy days, and 9
days with thunder.
Once again daily max/min temperatures didn’t vary very much, a typical
trend during the summer period. My maximum temperature frequencies
included 5 days over 90°, 20 days between 80° and 89°, and 6 days
between 70° and 79°. On the minimum temperature frequency side of
things, there were 2 days below 60°, 14 days between 60° and 69°
and 15 days 70° and above. The coldest daily max temperature was
72.6° on the cloudy 23rd while the warmest daily min temp of 73.9°
was on the 13th, when the temps were muted due to high dew points
and a lot of clouds.
The diurnal range daily monthly average was 17.0° (- 3.0°).
Our greatest daily range of temperature was 26.1° on the 30th
(85.5°-59.4°). We had a total of 8 days with daily ranges above
20°. Our lowest range of temperature was 7.6° (72.6°-65.0°) on
the 23rd (our coolest max day of the month). There were only 3
total days with diurnal temperature ranges of less than 10°
throughout the month, occurring on three of the many cloudy
days during the month but not particularly rainy/stormy at all. .
August 2019 was a typical mid-summer month, with heat, humidity
and numerous heavy thunderstorms predominating and only two
significantly long dry spells. Incredible Hurricane Dorian formed
during August and ravaged the Bahamas and the SE coast of the
United States into early September, but spared my area of
Maryland fortunately. .
AUGUST 2019
ROCKVILLE 2.8 WNW MARYLAND
SUMMARY STATISTICS
Average high temperature 84.5° (+ 0.3°)
Average low temperature 67.6° (+ 3.4°)
Mean temperature 76.0° (+ 1.8°)
Precipitation 7.63″ (+ 4.44“)
Greatest daily amount (date) 1.22″ (21)
Greatest storm total (dates) 2.53” (20-23)
2019 year-to-date precipitation total 37.66″ (+ 10.96”)
High temperature for the month (date) 92.2° (18)
Low temperature for the month (date) 59.4° (30)
Highest barometric pressure (date) 30.25” (25,31)
Lowest barometric pressure (date) 29.74” (7,8)
Peak wind gust (date/direction): N/A
Heating degree days for the month: 0
Cooling degree days for the month: 342
Greatest diurnal range (date): 26.1° (30)
Least diurnal range (date) 7.6° (23)
Number of days:
Fog 8
Windy 7
Thunder 9
Cloudy 10
Partly Cloudy 19
Sunny/Clear 2
Max temp ≥ 90° 5
Min temp < 60° 2
Min temp => 70° 15
Precip ≥ 0.01” 11
