Friday, April 23, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
FRIDAY, APRIL 23, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0450E
SUNSET: 1835E
BUSY WIND AND LOW DEWS PERSIST, BUT WARMER….
Wind is once again very active today with a max speed
of 40 mph and an average hovering around 20 MPH from the
west. The air is very dry with dew points in the mid-20s
adding a bit of a wind chill factor out there. The
combination of low dew points, gusty winds, and
relative humidity values around 30% is prompting an
elevated fire danger today. Skies are clear allowing
for plentiful sunshine.
After yesterday’s -13F daily departure, we are still
seasonably chilly, but the core of the cold blast
is now behind us. Highs have crept into the mid-50s
this afternoon…much closer to normal!
We continue to hold our “Climb for Climate” event up here.
Our challenge to our Greater Boston community is to climb
up Great Blue Hill to the Observatory and be counted as a
supporter of Mother Earth. We have logged nearly 200 people
since yesterday’s start. The weather for today and especially
tomorrow look very favorable for a visit. We also continue to
provide rooftop tours and are open until 4 P.M. Visibility
is right around 65 miles today.
The high so far today is 56F, this is 3 degrees below the
normal high of 59F. The low since midnight is 32F, which
is 9 degrees below the daily normal low of 41F.
Today’s Observations:
7 A.M.
Weather: Clear (few cirrus distant NNW-E)
Temperature: 38F; Dew Point: 23F; Relative Humidity: 55%
Wind: W at 15G24 kts (Peak of 32 MPH (28 kts) W at 6:17 A.M.)
Sea-level pressure: 29.85 in Hg, rising, then rising more slowly
Visibility: 65 miles, hazy
6-hr Max temp: 38F
6-hr Min temp: 32F
24-hr Precip: TRACE
24-hr Snow: TRACE
Snow Depth: 0.0 ins.
BHO SA 1155 CLR 65 108/38/23/2715G24/985/ FEW CI DSNT NNW-E
HAZY TOTAL NEW SNW PST 24 HRS TRACE PK WND 2628/17/ 8/001 51009
70000 10038 20032
10 A.M.
Weather: Scattered Cumulus
Temperature: 49F; Dew Point: 23F; Relative Humidity: 35%
Wind: WNW @ 22G35 kts (Peak of 40 MPH (35 kts) WNW at 9:49 A.M.)
Sea-level pressure: 29.82 in Hg; falling, then falling more rapidly
Visibility: 65 miles, hazy
3-hr Precip: 0.00 ins.
3-hr Snow: 0.00 ins.
BHO SA 1455 50 SCT 65 098/49/23/2922G35/982/ HAZY
PK WND 2935/49/ 8/100 58010
1 P.M.
Weather: Scattered Cumulus
Temperature: 55F, Dew point: 24F; Relative Humidity: 30%
Wind: WNW @ 16G30 kts (Peak of 44 MPH (38 kts) W at 12:59 P.M.)
Sea-level pressure: 29.79 in Hg; falling, then falling more slowly
Visibility: 65 miles, hazy
6-hr Max temp: 56F
6-hr Min temp: 38F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 1755 70 SCT 65 088/55/24/3016G30/979/ HAZY
PK WND 2738/1659/ 8/100 56010 10056 20038
SUMMARY FOR THURSDAY, APRIL 22, 2021
TEMPERATURE (DEGREES F)
MAX…….44 NORMAL…..58
MIN…….28 NORMAL…..40
MEAN……36 NORMAL…..49
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….-13
TOTAL DEPARTURE FOR THE MONTH……………….+30 [+1.2 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………29 DEPARTURE……+13
TOTAL HEATING UNITS FOR THE MONTH…………..406 DEPARTURE……-31
TOTAL HEATING UNITS FOR THE SEASON…………5228 DEPARTURE…..-693
TOTAL HEATING UNITS LAST SEASON TO DATE…….5348 DEPARTURE…..-120
PEAK WIND GUST (MPH):
420C/Official…………..54 W @ 2:11 P.M.
AEROVANE (south tower)…..55 W @ 2:11 P.M
ASOS…………………..51 W @ 2:11 P.M
DAVIS #1……………….55 W @ 2:10 P.M
DAVIS #2 (south tower)…..53 WNW @ 2:11 P.M
RMY……………………59 @ 2:09 P.M
VECTOR…………………59 @ 2:10 P.M
MERLIN…………………51
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………41 W @ 2:12 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….38 W @ 2:12 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………43 W @ 2:11 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………41 W @ 2:11 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..36 W @ 2:08 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..39 @ 2:09 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……22.0 WNW [527 total miles] ASOS…………………20.4
DAVIS #1……………..21.9 WNW
DAVIS #2……………..22.2 WNW
RMY………………….19.3 WNW
VECTOR……………… 20.0
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………….4.01 DEPARTURE….+0.53
ASOS………….3.91
TOTAL PRECIPITATION FOR THE YEAR………….14.18 DEPARTURE….-3.29
ASOS………..14.42
SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………TRACE DEPARTURE……0.0
TOTAL SNOWFALL FOR THE MONTH ………………3.6 DEPARTURE…..+0.8
TOTAL SNOWFALL FOR THE SEASON……………..76.2 DEPARTURE….+14.2
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 72/45/59/+10/0.00/0.0/…/.. 38 SW AERO 37 WSW RMY 40
04/21 68/32/50/+1/0.48/…/…/.. 45 S AERO 51 S RMY 51
04/22 44/28/36/-13/T/T/…/.. 54 W AERO 55 W RMY 59
04/23 The low since midnight is 32F, the daily normal low is 41F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR APRIL 23
HIGH 85 IN 1908, 2007
LOW 25 IN 1933,1989
PRECIP 1.99 IN. IN 2012
SNOWFALL 0.5 IN. IN 1911, 1956
PEAK GUST 64 MPH WNW IN 1962
RECORDS FOR APRIL 24
HIGH 82 IN 2001
LOW 22 IN 1930
PRECIP 2.51 INS IN 1898
SNOWFALL 1.2 INS IN 1967
PEAK GUST 59 MPH NW IN 1962
TODAY’S REPORT PREPARED BY: Andrew Swanson
