Friday, May 21, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
FRIDAY, MAY 21, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0417E
SUNSET: 1905E
MOSTLY CLOUDY AND WARM WITH A LIGHT
SOUTHWESTERLY BREEZE….
Today was mostly cloudy with skies becoming overcast
in the afternoon hours. Visibility was limited to only
35 miles due to a smoke layer moving in from southern
Canada’s wildfires. Wind shifted from southeast to
east with an average speed of 10 mph. The max gust
so far today is 19 mph.
The precipitation deficit continues at 4 inches on
the year and about a half inch for the month. The
lack of wind in the region is fortunate since there
is a lower chance of a brush fire.
The high so far today is 78F, which is 10 degrees
above the normal high of 68F. The low since midnight
is 50F, which is a degree above the daily normal low
of 49F.
Today’s Observations:
7 A.M.
Weather: Broken altocumulus and cirrostratus
Temperature: 55F; Dew Point: 48F; Relative Humidity: 76%
Wind: SSW @ 10 kts
Sea-level pressure: 30.51 in. Hg; falling then rising
Visibility: 55 miles, thin smoke layer
6-hr Max temp: 55F
6-hr Min temp: 50F
24-hr Precip: 0.00 ins.
BHO SA 1155 140 BKN 250 BKN 55 333/55/48/2210/051/ THN K
LYR ALQDS/ 8/077 51005 10055 20050
10 A.M.
Weather: Broken altocumulus and cirrostratus
Temperature: 72F; Dew Point: 47F; Relative Humidity: 41%
Wind: SSW @ 9 kts
Sea-level pressure: 30.48 in Hg; falling steadily
Visibility: 35 miles, smoke layer
3-hr Precip: 0.00 ins.
BHO SA 1455 120 BKN 250 BKN 35 323/72/47/2209/048/ K LYR
ALG HRZN/ 8/077 58010
1 P.M.
Weather: Broken altocumulus, overcast cirrostratus
Temperature: 73F, Dew point: 51F; Relative Humidity: 46%
Wind: S @ 9 kts
Sea-level pressure: 30.44 in Hg; falling steadily
Visibility: 35 miles, smoke
6-hr Max temp: 78F
6-hr Min temp: 55F
6-hr Precip: 0.00 ins.
BHO SA 1755 120 BKN 250 BKN 35 309/73/51/1909/044/ K LYR ALG
HRZN/ 8/078 58014 10078 20055
SUMMARY FOR THURSDAY, MAY 20, 2021
TEMPERATURE (DEGREES F)
MAX…….75 NORMAL…..68
MIN…….52 NORMAL…..49
MEAN……64 NORMAL…..58
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….+6
TOTAL DEPARTURE FOR THE MONTH……………….+33 [+1.5 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………… 1 DEPARTURE…….-7
TOTAL HEATING UNITS FOR THE MONTH…………..160 DEPARTURE……-40
TOTAL HEATING UNITS FOR THE SEASON…………5501 DEPARTURE…..-734
TOTAL HEATING UNITS LAST SEASON TO DATE…….5765 DEPARTURE…..-264
COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0 DEPARTURE…….-1
TOTAL COOLING UNITS FOR THE MONTH…………… 4 DEPARTURE…….-6
TOTAL COOLING UNITS FOR THE SEASON………….. 4 DEPARTURE…….-8
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2 DEPARTURE…….+2
PEAK WIND GUST (MPH):
420C/Official…………..18 ESE @ 4:12 P.M.
AEROVANE (south tower)…..18 ESE @ 4:14 P.M.
ASOS…………………..19 ESE @ 12:06 P.M.
DAVIS #1……………….20 S @ 4:17 P.M.
DAVIS #2 (south tower)…..20 S @ 8:08 P.M.
RMY……………………19 @ 2:28 P.M.
VECTOR…………………20 @ 2:29 P.M.
MERLIN…………………18
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………14 ESE @ 4:14 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….15 S @ 7:47 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………14 ESE @ 4:13 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 S @ 8:08 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..14 SSW @ 7:44 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..14 @ 4:10 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……7.2 SE [172 total miles] ASOS…………………7.7
DAVIS #1……………..7.6 SSE
DAVIS #2……………..7.7 SSE
RMY………………….7.3 SSE
VECTOR……………….7.8
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00 DEPARTURE….-0.13
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….1.80 DEPARTURE….-0.68
ASOS………….1.74
TOTAL PRECIPITATION FOR THE YEAR………….16.86 DEPARTURE….-4.17
ASOS………..17.02
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/-3/0.06/0.0/659/78 31 WNW AERO 35 WNW RMY 40
05/02 76/48/62/+9/0.01/0.0/220/26 41 SW AERO 41 SW RMY 46
05/03 67/48/58/+5/0.07/0.0/400/47 21 E AERO 20 E RMY 20
05/04 50/44/47/-7/0.78/0.0/000/00 36 NNE AERO 32 NNE RMY 37
05/05 48/44/46/-8/0.47/0.0/000/00 18 ESE AERO 14 ESE RMY 17
05/06 64/45/55/+1/0.00/0.0/780/91 33 NW AERO 38 NNW RMY 39
05/07 61/43/52/-3/0.00/0.0/516/60 28 ESE AERO 22 ESE RMY 26
05/08 54/40/47/-8/0.00/0.0/069/08 24 SSW AERO 23 SSW RMY 25
05/09 66/42/54/-1/T/0.0/579/67 30 SW AERO 29 SW RMY 34
05/10 60/45/53/-2/0.39/0.0/…/.. 21 W AERO 20 W RMY 20
05/11 63/45/54/-2/0.00/0.0/…/.. 38 WNW AERO 41 WNW RMY 41
05/12 65/41/53/-3/0.00/0.0/…/.. 28 NW AERO M M RMY 31
05/13 69/45/57/+1/0.00/0.0/…/.. 22 WNW AERO 21 WNW RMY 21
05/14 76/49/63/+8/0.00/0.0/…/.. 23 WNW AERO 23 WNW RMY 25
05/15 75/55/65/+8/0.01/0.0/…/.. 24 SSE AERO 26 SSE RMY 26
05/16 78/54/66/+9/0.01/0.0/…/.. 36 W AERO 37 W RMY 42
05/17 77/52/65/+8/0.00/0.0/…/.. 20 SSW AERO 21 SSW RMY 21
05/18 81/54/68/+10/T/0.0/…/.. 32 W AERO 30 W RMY 32
05/19 75/55/65/+7/0.00/0.0/…/.. 25 NE AERO 23 NNE RMY 27
05/20 75/52/64/+6/0.00/0.0/…/.. 18 ESE AERO 18 ESE RMY 19
05/21 The low since midnight is 50F, the daily normal low is 49F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR MAY 21
HIGH 92F IN 1921
LOW 35F IN 1907
PRECIP 1.61 INS IN 1954
PEAK GUST 74 MPH WSW IN 2006
RECORDS FOR MAY 25
HIGH 91F IN 2007
LOW 37F IN 1967
PRECIP 3.73 INS IN 1967
PEAK GUST 83 MPH NE IN 1967 (RECORD FOR MAY
TODAY’S REPORT PREPARED BY: Benjamin Turner
