Wednesday, April 28, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
WEDNESDAY, APRIL 28, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0444E
SUNSET: 1841E
MOSTLY CLOUDY WITH LIMITED VISIBILITY ATOP GREAT BLUE
HILL….
We observed mostly cloudy skies starting from an overcast
this morning. After measuring 0.18 inches of rainfall at the
7 A.M. observation, the overcast broke. This left us with a
mix of low, mid, and upper level clouds; along with some
intermittent sunshine. Wind was lighter, moving from east to
northeast as the day went on. The max gust is only 17 mph as
of yet.
Visibility was limited due to a smoke layer earlier on, then
a haze this afternoon. We started the day with 55 miles and
dropped to 35 miles.
The high so far today is 63F, this is 2 degrees above the
normal high of 61F. The low since midnight is 46F, which
is 4 degrees above the daily normal low of 42F.
Today’s Observations:
7 A.M.
Weather: Scattered stratocumulus, overcast altocumulus
Temperature: 50F; Dew Point: 47F; Relative Humidity: 87%
Wind: E at 10 kts
Sea-level pressure: 29.91 in Hg, rising, then falling
Visibility: 55 miles, thin smoke layer
6-hr Max temp: 53F
6-hr Min temp: 46F
24-hr Precip: 0.18 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 50 SCT 100 OVC 55 130/50/47/1010/991/ THN K
LYR ALQDS/ 8/82/ 70018 58006 10053 20046
10 A.M.
Weather: Scattered stratocumulus and altostratus, broken
cirrostratus
Temperature: 59F; Dew Point: 50F; Relative Humidity: 73%
Wind: E @ 4 kts, light and variable
Sea-level pressure: 29.92 in Hg; rising, then falling
Visibility: 35 miles, hazy
3-hr Precip: 0.00 ins.
3-hr Snow: 0.00 ins.
BHO SA 1455 50 SCT 100 BKN 250 BKN 35 134/59/50/0904/992/
HAZY WND L/V/ 8/828 50004
1 P.M.
Weather: Scattered cumulus and altostratus, broken
cirrostratus
Temperature: 60F, Dew point: 48F; Relative Humidity: 64%
Wind: NE @ 9G16 kts
Sea-level pressure: 29.87 in Hg; falling, then more slowly
Visibility: 35 miles, hazy
6-hr Max temp: 63F
6-hr Min temp: 50F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 40 SCT 75 BKN 250 BKN 35 117/60/48/0509G16/987/
HAZY/ 8/116 58017 10063 20050
SUMMARY FOR TUESDAY, APRIL 27, 2021
TEMPERATURE (DEGREES F)
MAX…….67 NORMAL…..60
MIN…….38 NORMAL…..42
MEAN……53 NORMAL…..51
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……. +2
TOTAL DEPARTURE FOR THE MONTH……………….+30 [+0.9 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………12 DEPARTURE…….-2
TOTAL HEATING UNITS FOR THE MONTH…………..479 DEPARTURE……-32
TOTAL HEATING UNITS FOR THE SEASON…………5301 DEPARTURE…..-694
TOTAL HEATING UNITS LAST SEASON TO DATE…….5460 DEPARTURE…..-159
PEAK WIND GUST (MPH):
420C/Official…………..26 W @ 1:52 P.M.
AEROVANE (south tower)…..28 WNW @ 1:46 P.M
ASOS…………………..26 W @ 1:52 P.M
DAVIS #1……………….28 W @ 1:52 P.M
DAVIS #2 (south tower)…..29 WNW @ 1:49 P.M
RMY……………………28 @ 1:30 P.M
VECTOR…………………29 @ 1:52 P.M
MERLIN…………………26
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………22 W @ 1:54 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….21 W @ 1:52 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………23 W @ 1:53 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………22 W @ 1:53 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..19 WNW @ 1:50 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..21 @ 1:50 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……11.7 WNW [280 total miles] ASOS…………………11.5
DAVIS #1……………..12.2 WNW
DAVIS #2……………..12.3 W
RMY………………….10.8 W
VECTOR……………….11.6
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.18 DEPARTURE….+0.05
ASOS………….0.17
TOTAL PRECIPITATION FOR THE MONTH………….4.39 DEPARTURE….+0.24
ASOS………….4.29
TOTAL PRECIPITATION FOR THE YEAR………….14.56 DEPARTURE….-3.58
ASOS………..14.80
SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0 DEPARTURE….. 0.0
TOTAL SNOWFALL FOR THE MONTH ………………3.6 DEPARTURE…..+0.7
TOTAL SNOWFALL FOR THE SEASON……………..76.2 DEPARTURE….+14.1
PRELIMINARY CLIMATE SUMMARY FOR APRIL 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
04/01 56/30/43/+2/0.89/T/000/00 44 NW AERO 51 NW RMY 49
04/02 37/24/31/-10/0.00/0.0/614/80 28 NW AERO 32 NNW RMY 30
04/03 48/23/36/-6/0.00/0.0/755/98 24 NW AERO 25 NW RMY 26
04/04 58/33/46/+4/0.00/0.0/734/95 38 NNW AERO 41 NNW RMY 41
04/05 57/41/49/+6/T/T/031/04 41 NNW AERO 48 NNW RMY 50
04/06 61/40/51/+8/0.00/0.0/412/53 26 NNW AERO 25 NNW RMY 31
04/07 57/41/49/+6/0.00/0.0/391/50 23 ENE AERO 21 ENE RMY 22
04/08 59/43/51/+7/0.00/0.0/745/95 22 ENE AERO 22 ENE RMY 24
04/09 69/42/56/+12/0.00/0.0/707/90 24 S AERO M M RMY 26
04/10 75/43/59/+14/0.00/0.0/576/73 26 SSW AERO 28 SSW RMY 30
04/11 53/40/47/+2/T/0.0/000/00 33 ENE AERO 33 ENE RMY 34
04/12 46/37/42/-3/0.05/0.0/000/00 36 ENE AERO 37 ENE RMY 41
04/13 56/37/47/+1/T/0.0/415/52 31 NE AERO 30 NE RMY 33
04/14 56/42/49/+3/0.00/0.0/729/91 22 ESE AERO 23 ESE RMY 22
04/15 51/37/44/-3/0.30/0.0/016/02 26 ESE AERO 25 ESE RMY 28
04/16 39/31/35/-12/2.22/3.6/000/00 48 NNW AERO 58 NNW RMY 58
04/17 45/34/40/-7/0.07/T/040/05 27 NNW AERO 30 NNW RMY 29
04/18 60/38/49/+1/0.00/0.0/666/82 28 NW AERO 28 NW RMY 31
04/19 66/44/55/+7/T/0.0/…/.. 22 SSW AERO 25 SSW RMY 28
04/20 72/45/59/+10/0.00/0.0/…/.. 38 SW AERO 37 WSW RMY 40
04/21 68/32/50/+1/0.48/*T/…/.. 45 S AERO 51 S RMY 51 TSTM
04/22 44/28/36/-13/T/T/…/.. 54 W AERO 55 W RMY 59
04/23 58/32/45/-5/0.00/0.0/…/.. 47 W AERO 48 W RMY 52
04/24 70/44/57/+7/0.00/0.0/…/.. 33 WNW AERO 37 WNW RMY 55
04/25 54/44/49/-1/0.20/0.0/…/.. 23 NNE AERO 20 SSW RMY 24
04/26 55/40/48/-3/0.00/0.0/…/.. 39 NW AERO 40 NW RMY 43
04/27 67/38/53/+2/T/0.0/…/.. 26 W AERO 28 WNW RMY 28
04/28 The low since midnight is 46F, the daily normal low is 42F
*Trace of frozen on 04/21 was hail, 1/8″ diameter, this does not
count as snowfall.
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR APRIL 28
HIGH 92 IN 1990, 2009
LOW 26 IN 1947
PRECIP 2.41 IN 1904
SNOWFALL 10.0 IN. IN 1987
PEAK GUST 69 MPH NE 1967
RECORDS FOR APRIL 29
HIGH 85 IN 1974
LOW 26 IN 1909
PRECIP 1.65 IN 1923
SNOWFALL 1.0 IN. IN 1987
PEAK GUST 55 MPH WNW IN 2010
TODAY’S REPORT PREPARED BY: Benjamin Turner
