Thursday, May 20, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
THURSDAY, MAY 20, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0418E
SUNSET: 1904E
A FAIR WEATHER DAY WITH LIGHT WIND AND
LIMITED VISIBILITY….
Today was mostly clear save some upper level clouds
throughout the day. Visibility was around 50 miles
on average, the wind was almost calm.
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 75F, which is 7 degrees
above the normal high of 68F. The low since midnight
is 53F, which is 4 degrees above the daily normal low
of 49F.
Today’s Observations:
7 A.M.
Weather: Scattered cirrus
Temperature: 64F; Dew Point: 40F; Relative Humidity: 40%
Wind: Calm
Sea-level pressure: 30.50 in. Hg; rising steadily
Visibility: 65 miles, thin smoke layer
6-hr Max temp: 64F
6-hr Min temp: 53F
24-hr Precip: 0.00 ins.
BHO SA 1155 250 SCT 65 329/64/40/0000/050/ THN K LYR ALQDS/
8/001 51018 10064 20053
10 A.M.
Weather: Scattered cirrus
Temperature: 70F; Dew Point: 35F; Relative Humidity: 27%
Wind: ESE @ 4 kts, light and variable
Sea-level pressure: 30.51 in Hg; steady, then rising
Visibility: 55 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 250 SCT 55 331/70/35/1204/051/ WND L/V/
8/001 50002
1 P.M.
Weather: Clear, few cirrus
Temperature: 73F, Dew point: 44F; Relative Humidity: 35%
Wind: E @ 10G15 kts
Sea-level pressure: 30.49 in Hg; falling, then steady
Visibility: 60 miles
6-hr Max temp: 75F
6-hr Min temp: 64F
6-hr Precip: 0.00 ins.
BHO SA 1755 250 SCT 60 326/73/44/0810G15/049/ 8/001 58005
10075 20064
SUMMARY FOR WEDNESDAY, MAY 19, 2021
TEMPERATURE (DEGREES F)
MAX…….75 NORMAL…..67
MIN…….55 NORMAL…..49
MEAN……65 NORMAL…..58
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….+7
TOTAL DEPARTURE FOR THE MONTH……………….+27 [+1.2 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………… 0 DEPARTURE…….-8
TOTAL HEATING UNITS FOR THE MONTH…………..159 DEPARTURE……-34
TOTAL HEATING UNITS FOR THE SEASON…………5500 DEPARTURE…..-728
TOTAL HEATING UNITS LAST SEASON TO DATE…….5753 DEPARTURE…..-253
COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0 DEPARTURE…….-1
TOTAL COOLING UNITS FOR THE MONTH…………… 4 DEPARTURE…….-5
TOTAL COOLING UNITS FOR THE SEASON………….. 4 DEPARTURE…….-7
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2 DEPARTURE…….+2
PEAK WIND GUST (MPH):
420C/Official…………..25 NE @ 6:28 A.M.
AEROVANE (south tower)…..23 NNE @ 6:17 A.M.
ASOS…………………..26 NE @ 6:29 A.M.
DAVIS #1……………….25 ENE @ 6:29 A.M.
DAVIS #2 (south tower)…..27 ENE @ 6:28 A.M.
RMY……………………27 @ 6:24 A.M.
VECTOR…………………27 @ 6:25 A.M.
MERLIN…………………N/A
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………17 NE @ 6:34 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….17 NE @ 6:55 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………18 ENE @ 6:55 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………18 NE @ 6:28 A.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..17 ENE @ 6:24 A.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..17 @ 6:25 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……9.4 ENE [226 total miles] ASOS…………………9.3
DAVIS #1……………..9.8 ENE
DAVIS #2……………..9.7 ENE
RMY………………….9.3 SE
VECTOR……………….9.8
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00 DEPARTURE….-0.14
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….1.80 DEPARTURE….-0.55
ASOS………….1.74
TOTAL PRECIPITATION FOR THE YEAR………….16.86 DEPARTURE….-4.04
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 The low since midnight is 53F, 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 20
HIGH 91F IN 1975,1996
LOW 37F IN 1948, 2002
PRECIP 1.65 INCHES IN 1969
PEAK GUST 57 MPH S IN 1963, WNW IN 1982
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
TODAY’S REPORT PREPARED BY: Benjamin Turner
