Tuesday, May 11, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
TUESDAY, MAY 11, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0427E
SUNSET: 1855E
BRIGHT SUNSHINE AND SEASONABLE TEMPERATURES, BUT WINDY….
Some early morning cloudiness moved out leaving us with
abundant sunshine for the balance of the day. However
rather strong mixing from aloft is helping to generate
some gusty westerly winds.
The average speed is around 15 mph since 7 A.M. with gusts
frequently getting over 30 mph.
The mixing is also pulling dryer air down from aloft with
the dew point dropping into the mid 20s. This is generating
relative humidities between 20-25%.
With the very dry air, visibility has been excellent for
this time of year, pushing 70 miles early this afternoon!
The high so far today is 62F, this is 3 degrees below the
normal high of 65F. The low since midnight is 46F, which
is equal to 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: 2.22 ins. on the 16th
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: 12444 minutes of a possible 23250 or 54%
Astronomical total minutes: 12904 minutes of a possible 24128 or 54%
Today’s Observations:
7 A.M.
Weather: Broken dense cirrus, thin broken cirrus
Temperature: 51F; Dew Point: 35F; Relative Humidity: 53%
Wind: W at 9G16 kts
Sea-level pressure: 29.96 in/Hg, steady, then rising
Visibility: 50 miles
6-hr Max temp: 51F
6-hr Min temp: 46F
24-hr Precip: 0.00 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 E200 BKN 250 -BKN 50 144/51/35/2809G16/996/
FEW CU DSNT WNW-NW/ 8/002 53008 10051 20046
10 A.M.
Weather: Scattered stratocumulus/cumulus, thin scattered cirrus
Temperature: 58F; Dew Point: 24F; Relative Humidity: 26%
Wind: W @ 13G25 kts, peak wind W 33 mph at 9:41 A.M.
Sea-level pressure: 29.94 in Hg; falling, then more slowly
Visibility: 70 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 55 SCT 250 -SCT 70 140/58/24/2713G25/994/
PK WND 2828/41/ 8/801 56004
1 P.M.
Weather: Scattered cumulus, thin scattered cirrus
Temperature: 61F, Dew point: 24F; Relative Humidity: 24%
Wind: W @ 16G30 kts, peak wind W 35 mph at 12:46 P.M.
Sea-level pressure: 29.91 in Hg; falling, then more rapidly
Visibility: 70 miles
6-hr Max temp: 62F
6-hr Min temp: 51F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 55 SCT 250 -SCT 70 128/61/24/2616G30/991/
PK WND 2730/46/ 8/201 58012 10062 20051
SUMMARY FOR MONDAY, MAY 10, 2021
TEMPERATURE (DEGREES F)
MAX…….60 NORMAL…..65
MIN…….45 NORMAL…..46
MEAN……53 NORMAL…..55
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……. -2
TOTAL DEPARTURE FOR THE MONTH……………….-17 [-1.9 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………12 DEPARTURE…….+2
TOTAL HEATING UNITS FOR THE MONTH…………..126 DEPARTURE……+13
TOTAL HEATING UNITS FOR THE SEASON…………5467 DEPARTURE…..-681
TOTAL HEATING UNITS LAST SEASON TO DATE…….5653 DEPARTURE…..-186
COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0 DEPARTURE……. 0
TOTAL COOLING UNITS FOR THE MONTH…………… 0 DEPARTURE…….-3
TOTAL COOLING UNITS FOR THE SEASON………….. 0 DEPARTURE…….-5
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2 DEPARTURE…….-2
PEAK WIND GUST (MPH):
420C/Official…………..21 W @ 11:23 P.M.
AEROVANE (south tower)…..20 W @ 11:20 P.M.
ASOS…………………..19 NNE @ 7:12 P.M.
DAVIS #1……………….20 W @ 11:23 P.M.
DAVIS #2 (south tower)…..18 SSW @ 7:30 P.M.
RMY……………………20 @ 11:25 P.M.
VECTOR…………………19 @ 11:23 P.M.
MERLIN…………………21
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 W @ 11:26 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….15 W @ 11:23 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………15 W @ 11:23 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 W @ 11:30 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..14 W @ 11:20 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..14 @ 11:20 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…… 6.3 NNE [152 total miles] ASOS………………… 6.4
DAVIS #1…………….. 6.5 WSW
DAVIS #2…………….. 6.7 SW
RMY…………………. 6.3 SSE
VECTOR………………. 6.8
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………….1.78 DEPARTURE….+0.55
ASOS………….1.73
TOTAL PRECIPITATION FOR THE YEAR………….16.84 DEPARTURE….-2.94
ASOS………..17.01
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/-7/0.78/0.0/…/.. 36 NNE AERO 32 NNE RMY 37
05/05 48/44/46/-8/0.45/0.0/…/.. 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 66/42/54/-1/T/0.0/…/.. 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 The low since midnight is 46F, 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 11
HIGH 90F IN 1993
LOW 28F IN 1900
PRECIP 1.28 INS IN 1957
SNOW 1.0 INS IN 1907 (LATEST MEASURABLE SNOW ON RECORD)
PEAK GUST 75e MPH NW IN 1945
RECORDS FOR MAY 12
HIGH 88F IN 2001
LOW 29F IN 1907
PRECIP 1.49 INCHES IN 1968
SNOW TRACE IN 2019
PEAK GUST 76 MPH S IN 1974
TODAY’S REPORT PREPARED BY: Matt Douglas
