Monday, May 10, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
MONDAY, MAY 10, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0428E
SUNSET: 1854E
OVERNIGHT RAIN ENDS, MAINLY CLOUDY DAY IN IT’S WAKE….
We got a decent drink of rain overnight with 0.39″ falling.
This brings the month to 1.78″ which is 0.67″ above normal
for the month to date.
Following the rain, we’ve seen mainly cloudy skies through
today with a very light onshore wind.
The average speed is only around 5 mph since 7 A.M. with a
peak gust so far of only around 20 mph.
Thanks to the combination of cloud cover and a light onshore
wind, temperatures for today have been held below normal
at least through the 1 P.M. observation.
The high so far today is 56F, this is 9 degrees below the
normal high of 65F. The low since midnight is 45F, which
is 1 degree below the daily normal low of 46F.
PRELIMINARY STATS FOR APRIL 2021
TEMPERATURE, Deg. F
Avg. Max. 57.2 [+1.5]Avg. Min. 37.8 [+0.1]Mean 47.5 [+0.8]24-hour corrected mean: 47.0
Max. for month: 75F on the 10th
Min. for month: 23F on the 3rd
HEATING DEGREE DAYS
Total heating units: 519 [-32]Total for the season: 5341 [-694]Total for last season: 5521
PRECIPITATION, Inches
Total: 4.89 [+0.45]Greatest in 24 hrs: 2.22 ins. on the 16th
SNOWFALL, Inches
Total: 3.6 [+0.6]Greatest in 24 hrs: 3.6 ins. on the 16th
WIND, mph
Avg. uncorrected wind speed: 12.1 mph
Avg. corrected wind speed: 12.5 mph
Prevailing wind direction: WNW [16%]Peak gust and direction: 58 WNW on the 30th
SUNSHINE:
Campbell-Stokes card minutes: 12444 minutes of a possible 23250 or 54%
Astronomical total minutes: 12904 minutes of a possible 24128 or 54%
Today’s Observations:
7 A.M.
Weather: Broken stratus fractus, overcast status
Temperature: 46F; Dew Point: 46F; Relative Humidity: 100%
Wind: NNE at 7 kts
Sea-level pressure: 29.82 in Hg, steady, then rising
Visibility: 15 miles, thin fog
6-hr Max temp: 46F
6-hr Min temp: 45F
24-hr Precip: 0.39 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 E5 BKN 30 OVC 15 097/46/46/0207/982/
FEW LWR STFRA ALQDS FEW BINOVC NW-N THN F ALQDS/
8/6// 53011 6037/ 70039 10046 20045
10 A.M.
Weather: Broken stratocumulus/cumulus, overcast stratocumulus
Temperature: 54F; Dew Point: 44F; Relative Humidity: 68%
Wind: NNE @ 7 kts
Sea-level pressure: 29.86 in Hg; rising, then more rapidly
Visibility: 70 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 E20 BKN 40 OVC 70 111/54/44/0307/986/ 8/4// 53014
1 P.M.
Weather: Broken stratocumulus/cumulus, broken stratocumulus,
broken altocumulus, thin broken cirrus
Temperature: 56F, Dew point: 42F; Relative Humidity: 59%
Wind: Calm
Sea-level pressure: 29.86 in Hg; rising, then falling
Visibility: 60 miles
6-hr Max temp: 56F
6-hr Min temp: 46F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E35 BKN 45 BKN 120 BKN 250 -BKN 60 111/56/42/0000/986/
WND CALM/ 8/461/ 50000 10056 20046
SUMMARY FOR SUNDAY, MAY 9, 2021
TEMPERATURE (DEGREES F)
MAX…….66 NORMAL…..64
MIN…….42 NORMAL…..46
MEAN……54 NORMAL…..55
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……. -1
TOTAL DEPARTURE FOR THE MONTH……………….-15 [-1.5 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………11 DEPARTURE…….+1
TOTAL HEATING UNITS FOR THE MONTH…………..114 DEPARTURE……+11
TOTAL HEATING UNITS FOR THE SEASON…………5455 DEPARTURE…..-683
TOTAL HEATING UNITS LAST SEASON TO DATE…….5633 DEPARTURE…..-178
COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0 DEPARTURE……. 0
TOTAL COOLING UNITS FOR THE MONTH…………… 0 DEPARTURE…….-3
TOTAL COOLING UNITS FOR THE SEASON………….. 0 DEPARTURE…….-5
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2 DEPARTURE…….-2
PEAK WIND GUST (MPH):
420C/Official…………..30 SW @ 6:59 P.M.
AEROVANE (south tower)…..29 SW @ 6:59 P.M.
ASOS…………………..31 SSW @ 6:59 P.M.
DAVIS #1……………….32 SW @ 6:58 P.M.
DAVIS #2 (south tower)…..31 SW @ 6:58 P.M.
RMY……………………34 @ 7:36 P.M.
VECTOR…………………33 @ 7:38 P.M.
MERLIN…………………31
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………22 SW @ 7:47 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….21 SW @ 7:39 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………22 W @ 3:32 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………23 SW @ 7:48 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..20 SW @ 7:45 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..21 @ 7:45 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……11.4 WSW [273 total miles] ASOS…………………10.8
DAVIS #1……………..11.7 W
DAVIS #2……………..11.5 W
RMY………………….10.6 W
VECTOR……………….11.2
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.39 DEPARTURE….+0.27
ASOS………….0.38
TOTAL PRECIPITATION FOR THE MONTH………….1.78 DEPARTURE….+0.67
ASOS………….1.73
TOTAL PRECIPITATION FOR THE YEAR………….16.84 DEPARTURE….-2.82
ASOS………..17.01
PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system gust
RMY: R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M: Missing data
05/01 62/38/50/-3/0.06/0.0/…/.. 31 WNW AERO 35 WNW RMY 40
05/02 76/48/62/+9/0.01/0.0/…/.. 41 SW AERO 41 SW RMY 46
05/03 67/48/58/+5/0.07/0.0/…/.. 21 E AERO 20 E RMY 20
05/04 50/44/47/-7/0.78/0.0/…/.. 36 NNE AERO 32 NNE RMY 37
05/05 48/44/46/-8/0.45/0.0/…/.. 18 ESE AERO 14 ESE RMY 17
05/06 64/45/55/+1/0.00/0.0/…/.. 33 NW AERO 38 NNW RMY 39
05/07 61/43/52/-3/0.00/0.0/…/.. 28 ESE AERO 22 ESE RMY 26
05/08 54/40/47/-8/0.00/0.0/…/.. 24 SSW AERO 23 SSW RMY 25
05/09 66/42/54/-1/T/0.0/…/.. 30 SW AERO 29 SW RMY 34
05/10 The low since midnight is 45F, the daily normal low is 46F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR MAY 10
HIGH 93F IN 1896
LOW 29F IN 1900
PRECIP 1.85 INS IN 1998
SNOW 2.8 INS 1977 (7.8 INS TOTAL 5/9-5/10 1977)
PEAK GUST 64 MPH S IN 1990
RECORDS FOR MAY 11
HIGH 90F IN 1993
LOW 28F IN 1900
PRECIP 1.28 INS IN 1957
SNOW 1.0 INS IN 1907 (LATEST MEASURABLE SNOW ON RECORD)
PEAK GUST 75e MPH NW IN 1945
TODAY’S REPORT PREPARED BY: Matt Douglas
