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BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
TUESDAY, APRIL 20, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0455E
SUNSET: 1832E
WINDY AND WARM WITH A MIX OF SUN AND CLOUDS….
Plenty of sunshine this morning has given way to some
cloudiness, a mix of lower cumulus indicating that we’ve
reached the convective temperature for today, and some
high thin cirrus.
The wind has been busy since about mid morning with a
peak gust of 37 mph thus far. The average speed since
7 A.M. has been around 14 mph, so definitely much
windier than yesterday.
Visibility has been limited today, from around 55 miles
this morning to 40 miles early this afternoon. This is
due to haziness, likely the result of pollen in the air.
The high so far today is 73F, this is 15 degrees above the
normal high of 58F. The low since midnight is 45F, which
is 5 degrees above the daily normal low of 40F.
Today’s Observations:
7 A.M.
Weather: Thin scattered cirrus, few altocumulus distant SW-WNW
Temperature: 51F; Dew Point: 38F; Relative Humidity: 60%
Wind: WSW at 8 kts
Sea-level pressure: 29.90 in Hg, rising, then more slowly
Visibility: 55 miles
6-hr Max temp: 51F
6-hr Min temp: 45F
24-hr Precip: Trace
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 250 -SCT 55 125/51/38/2408/990/ FEW AC DSNT SW-WNW
THN K LYR ALNG HRZN ALQDS/ 8/031 51014 70000 10051 20045
10 A.M.
Weather: Thin scattered cirrus, few small cumulus SW-NW,
few altocumulus distant WSW-NNW
Temperature: 65F; Dew Point: 34F; Relative Humidity: 31%
Wind: SSW @ 15G25 kts
Sea-level pressure: 29.89 in Hg; rising then falling
Visibility: 55 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 250 -SCT 55 122/65/34/2115G25/989/ FEW SML CU SW-NW
FEW AC DSNT WSW-NNW/ 8/031 58003
1 P.M.
Weather: Broken cumulus, thin broken cirrus
Temperature: 70F, Dew point: 34F; Relative Humidity: 26%
Wind: WSW @ 18G25 kts, peak wind SW 35 mph at 11:59 A.M.
Sea-level pressure: 29.82 in Hg; falling, then more rapidly
Visibility: 40 miles, hazy
6-hr Max temp: 73F
6-hr Min temp: 51F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E55 BKN 250 -BKN 40 105/70/34/2418G25/984/
HAZY PK WND 2230/59/ 8/201 56017 10073 20051
SUMMARY FOR MONDAY, APRIL 19, 2021
TEMPERATURE (DEGREES F)
MAX…….66 NORMAL…..57
MIN…….44 NORMAL…..39
MEAN……55 NORMAL…..48
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……. +7
TOTAL DEPARTURE FOR THE MONTH……………….+32 [+1.5 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………10 DEPARTURE…….-7
TOTAL HEATING UNITS FOR THE MONTH…………..356 DEPARTURE……-33
TOTAL HEATING UNITS FOR THE SEASON…………5178 DEPARTURE…..-694
TOTAL HEATING UNITS LAST SEASON TO DATE…….5276 DEPARTURE……-98
PEAK WIND GUST (MPH):
420C/Official…………..22 SSW @ 6:03 P.M.
AEROVANE (south tower)…..25 SSW @ 6:03 P.M.
ASOS…………………..24 SSW @ 6:04 P.M.
DAVIS #1……………….24 SSW @ 6:03 P.M.
DAVIS #2 (south tower)…..24 SW @ 6:03 P.M.
RMY……………………28 @ 6:03 P.M.
VECTOR…………………26 @ 6:03 P.M.
MERLIN…………………23
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 SW @ 6:06 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….16 SW @ 6:05 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 SW @ 6:04 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………17 SW @ 6:05 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..16 SW @ 6:03 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..16 @ 6:02 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…… 7.5 WNW [179 total miles] ASOS………………… 8.0
DAVIS #1…………….. 7.8 W
DAVIS #2…………….. 8.2 W
RMY…………………. 7.4 W
VECTOR……………… 7.9
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……TRACE DEPARTURE….-0.14
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….3.53 DEPARTURE….+0.46
ASOS………….3.42
TOTAL PRECIPITATION FOR THE YEAR………….13.70 DEPARTURE….-3.36
ASOS………..13.93
SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0 DEPARTURE…..-0.1
TOTAL SNOWFALL FOR THE MONTH ………………3.6 DEPARTURE…..+1.0
TOTAL SNOWFALL FOR THE SEASON……………..76.2 DEPARTURE….+14.4
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/…/.. 31 NE AERO 30 NE RMY 33
04/14 56/42/49/+3/0.00/0.0/…/.. 22 ESE AERO 23 ESE RMY 22
04/15 51/37/44/-3/0.30/0.0/…/.. 26 ESE AERO 25 ESE RMY 28
04/16 39/31/35/-12/2.22/3.6/…/.. 48 NNW AERO 58 NNW RMY 58
04/17 45/34/40/-7/0.07/T/…/.. 27 NNW AERO 30 NNW RMY 29
04/18 60/38/49/+1/0.00/0.0/…/.. 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 The low since midnight is 45F, the daily normal low is 40F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR APRIL 20
HIGH 88 IN 1927
LOW 18 IN 1897
PRECIP 1.14 IN 1972
SNOWFALL 2.5 IN. IN 1904, 1972
PEAK GUST 76 MPH WNW IN 1963
RECORDS FOR APRIL 21
HIGH 85 IN 1923
LOW 22 IN 1908
PRECIP 3.18 IN. IN 1991
SNOWFALL 0.8 IN. IN 1947
PEAK GUST 76e MPH NE IN 1940
TODAY’S REPORT PREPARED BY: Matt Douglas
