Sunday, May 9, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
SUNDAY, MAY 9, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0429E
SUNSET: 1851E
ANOTHER GOOD VISIBILITY DAY WITH INCREASING CLOUDS….
Today became overcast, starting from almost cloudless
skies at the 7 A.M. observation. Visibility is holding
at 75 miles on average, and we have observed a wind shift
from northwest to west as the day carried on. A notable
increase in wind has been observed since the shift, with
a max gust of almost 25 mph being observed since noon.
The high so far today is 64F, this is the same as the
normal high. The low since midnight is 42F, which
is 4 degrees below the daily normal low of 46F.
PRELIMINARY STATS FOR APRIL 2021
TEMPERATURE, Deg. F
Avg. Max. 57.2 [+1.5]Avg. Min. 37.8 [+0.1]Mean 47.5 [+0.8]24-hour corrected mean: 47.0
Max. for month: 75F on the 10th
Min. for month: 23F on the 3rd
HEATING DEGREE DAYS
Total heating units: 519 [-32]Total for the season: 5341 [-694]Total for last season: 5521
PRECIPITATION, Inches
Total: 4.89 [+0.45]Greatest in 24 hrs: N/A
SNOWFALL, Inches
Total: 3.6 [+0.6]Greatest in 24 hrs: 3.6 ins. on the 16th
WIND, mph
Avg. uncorrected wind speed: 12.1 mph
Avg. corrected wind speed: 12.5 mph
Prevailing wind direction: WNW [16%]Peak gust and direction: 58 WNW on the 30th
SUNSHINE:
Campbell-Stokes card minutes: N/A
Astronomical total minutes: N/A
Today’s Observations:
7 A.M.
Weather: Clear, few cirrostratus
Temperature: 49F; Dew Point: 40F; Relative Humidity: 70%
Wind: NW at 9 kts
Sea-level pressure: 29.97 in Hg, rising steadily
Visibility: 80 miles
6-hr Max temp: 49F
6-hr Min temp: 42F
24-hr Precip: 0.00 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 CLR 80 149/49/40/3109/997/ FEW CS ALQDS/ 8/008
51020 10049 20042
10 A.M.
Weather: Scattered cumulus and broken cirrostratus
Temperature: 59F; Dew Point: 36F; Relative Humidity: 42%
Wind: SSW @ 8 kts
Sea-level pressure: 29.97 in Hg; rising then falling
Visibility: 75 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 50 SCT 250 BKN 75 149/59/36/2108/997/ 8/106 58000
1 P.M.
Weather: Scattered altocumulus and broken cirrostratus
Temperature: 64F, Dew point: 31F; Relative Humidity: 28%
Wind: W @ 13G23 kts
Sea-level pressure: 29.91 in Hg; falling, then steady
Visibility: 75 miles
6-hr Max temp: 64F
6-hr Min temp: 49F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 70 SCT 250 BKN 75 131/64/31/2613G23/991/ 8/087
58018 10064 20049
SUMMARY FOR SATURDAY, MAY 8, 2021
TEMPERATURE (DEGREES F)
MAX…….54 NORMAL…..64
MIN…….40 NORMAL…..46
MEAN……47 NORMAL…..55
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……..-8
TOTAL DEPARTURE FOR THE MONTH……………….-14 [-2.0 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………18 DEPARTURE…….+8
TOTAL HEATING UNITS FOR THE MONTH…………..103 DEPARTURE……+10
TOTAL HEATING UNITS FOR THE SEASON…………5444 DEPARTURE…..-683
TOTAL HEATING UNITS LAST SEASON TO DATE…….5606 DEPARTURE…..-162
COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0 DEPARTURE……. 0
TOTAL COOLING UNITS FOR THE MONTH…………… 0 DEPARTURE…….-2
TOTAL COOLING UNITS FOR THE SEASON………….. 0 DEPARTURE…….-4
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2 DEPARTURE…….-2
PEAK WIND GUST (MPH):
420C/Official…………..24 SSW @ 6:45 P.M.
AEROVANE (south tower)…..23 SSW @ 6:51 P.M.
ASOS…………………..25 SSW @ 6:47 P.M.
DAVIS #1……………….24 SW @ 6:47 P.M.
DAVIS #2 (south tower)…..24 SW @ 6:47 P.M.
RMY……………………25 @ 6:46 P.M.
VECTOR…………………26 @ 6:46 P.M.
MERLIN…………………24
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………19 SSW @ 6:48 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….18 SSW @ 6:50 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………18 SSW @ 6:50 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………19 SSW @ 6:50 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..18 SSW @ 6:48 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..18 @ 6:47 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…… 8.7 NNE [209 total miles] ASOS………………… 9.5
DAVIS #1…………….. 9.1 NNE
DAVIS #2…………….. 9.1 NNE
RMY…………………. 8.6 E
VECTOR………………. 9.0
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00 DEPARTURE….-0.12
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….1.39 DEPARTURE….+0.40
ASOS………….1.35
TOTAL PRECIPITATION FOR THE YEAR………….16.45 DEPARTURE….-3.09
ASOS………..16.63
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/…/.. 31 WNW AERO 35 WNW RMY 40
05/02 76/48/62/+9/0.01/0.0/…/.. 41 SW AERO 41 SW RMY 46
05/03 67/48/58/+5/0.07/0.0/…/.. 21 E AERO 20 E RMY 20
05/04 50/44/47/-7/…./0.0/…/.. 36 NNE AERO 32 NNE RMY 37
05/05 48/44/46/-8/…./0.0/…/.. 18 ESE AERO 14 ESE RMY 17
05/06 64/45/55/+1/0.00/0.0/…/.. 33 NW AERO 38 NNW RMY 39
05/07 61/43/52/-3/0.00/0.0/…/.. 28 ESE AERO 22 ESE RMY 26
05/08 54/40/47/-8/0.00/0.0/…/.. 24 SSW AERO 23 SSW RMY 25
05/09 The low since midnight is 42F, the daily normal low is 46F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR MAY 9
HIGH 93F IN 2000
LOW 31F IN 1947
PRECIP 2.72 INCHES IN 1954
SNOWFALL 5.0 INS IN 1977 (RECORD FOR MAY)
PEAK GUST 70e MPH NE IN 1977
RECORDS FOR MAY 10
HIGH 93F IN 1896
LOW 29F IN 1900
PRECIP 1.85 INS IN 1998
SNOW 2.8 INS 1977 (7.8 INS TOTAL 5/9-5/10 1977)
PEAK GUST 64 MPH S IN 1990
TODAY’S REPORT PREPARED BY: Benjamin Turner
