FEBRUARY 2018 MONTHLY SUMMARY ROCKVILLE 2.8 WNW MARYLAND
By Kevin Shaw, Observer in Charge
February 2018 was one of the warmest Februarys ever among the 3 local major
airports with long records and official normals. The warmest period was on the
20th and 21st for maxima and on the 21st for minima and broke long standing
records at these airports. My 76° and 78° on those two consecutive days and
my 61° min on the 21st fit right in with the corresponding data from the major
airports at BWi, DCA and IAD. The first 10 days of the month was generally
the coldest period of the month, but still did not hold a 32 or lower max temp
all month. Rainfall was significantly above normal at these three airports, and
snowfall was well below normal, with only one day of snow on the 17th, curiously
also the max day for snow in January, though it was even a lesser amount (0.7”).
There were 16 days with measurable precipitation, assuredly what should be
significantly above average, topped off by the 1.13″ that occurred on the 4th.
The highest barometric pressure reading of the month (30.83″) on the 13th was
actually the highest I have had at my new station, surpassing the previous highest
pressure reading of 30.80” set back on January 9, 2017. The lowest barometric
pressure reading of the month (29.64″) occurred just three days later in the very
early morning hours of the 16th , just prior to our only snowfall of the month the
next day on the 17th.. The month was quite cloudy to go along with the bountiful
and frequent precipitation, with only 3 clear days logged along with 11 partly cloudy
and 14 cloudy days. The relatively cold period the first third of the month was
overwhelmed by the later in the month general warmth.at the three first-order
stations at the 3 major DC area airport locations to make it the warm month that
it was, near records at these official first-order locations. .
There were 618 heating degree days (HDD) and 5 cooling degree days (CDD) during
the month. There were many foggy days, 13 to be exact, only 1 day with snow, and
5 windy days. That is a subjective category with no real data values to back it, just
based on my email daily weather posts that are also posted on weathertogether.net.
There was 1 day with sleet and 3 days with glaze (both occurred on the 17th mixed
in with our only snowfall during the month with light amounts of glaze on the 4th and
7th ).
Daily max/min temperatures varied widely throughout the month. My maximum
temperature frequencies included 3 days over 70°, 5 days between 60° and 69°,
6 days between 50° and 59°, 7 days between 40° and 49°, and 7 days between
30° and 39°.. On the minimum temperature frequency side of things, 2 days
between 10° and 19°, 4 days between 20° and 29°, 14 days between 30° and
39°, 7 days between 40° and 49°, and 1 day above 60°. The coldest daily max
temperature was 32.8° on the 8th and warmest daily min temp was 61.2° on that
warmest day on the 21st.
The diurnal range daily monthly average was 15.5°. Our greatest daily range of
temperature was 30.6°, formed from a high of 67.1° and low of 36.5° during the
first of 2 mini-2 day “heat waves” during the month. This was the only day with a
range over 30°, We had an additional 8 days with daily ranges above 20°. Our
lowest range of temperature was 3.5° on our wettest (1.13”) day of the month
(13th) when our readings (34.6° and 31.1°) teetered precariously around the
freezing mark, mostly just above, to give us mostly all rain and just a bit of glaze.
There were a total of 8 days with diurnal temperature ranges less than 10.0°, an
increase of 2 over last month. The distribution of these low and high diurnal range
days was spread out fairly uniformly during the month.
With yet another month to study the most recent instrument changes made in mid-
August, data appears to be stable and an overall data quality improvement success.
I am still constantly checking on my data quality frequently along with some of my
Maryland weather cohorts. I have been swapping out gauges when frozen precipitation
occurs to allow for casual, comfortable melting inside my apartment. Unfortunately the
“snow stake” was pulled out early in February when high winds knocked it over partially
at a significant angle and has not been placed back outside through the current time.
I did get a new hand-held anemometer that is especially sensitive to light winds, a good
thing as that is a persistent trait at my relatively calm location. I also have continued
just about daily GLOBE Cloud observations, complete with submission of sky pictures at
the time of the observation, usually timed with the passage of satellites and also solar
noon right now with the time change about 70 minutes past actual EDT noon. Please ask
me any questions you want at any time about my station setup and/or my data through
any means available to you.
FEBRUARY 2018 – ROCKVILLE 2.8 WNW MARYLAND – SUMMARY STATISTICS
Average high temperature 50.8°
Average low temperature 35.4°
Mean temperature 43.1°
Precipitation 4.80″
Greatest daily amount (date) 1.13″ (4)
Snow 2.0″
Greatest daily amount (date) 2.0” (17)
2018 year-to-date precipitation total 6.63″
Seasonal snowfall total as of 2/28/2018 7.2″
High temperature for the month (date) 78.3° (21)
Low temperature for the month (date) 13.7° (3)
Highest barometric pressure (date) 30.83” (13)
Lowest barometric pressure (date) 29.64” (16)
Peak wind gust (date/direction): N/A
Heating degree days for the month: 618
Cooling degree days for the month: 5
Greatest diurnal range (date): 30.6° (16)
Least diurnal range (date) 3.5° (4)
Number of days:
Fog 13
Windy 6
Snow 1
Cloudy 14
Partly Cloudy 11
Sunny/Clear 3
Max temp = > 70° 3
Min temp < = 32° 12
Max temp < = 32° 0
Precip = > 0.01” 16
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