Tuesday, May 4, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
TUESDAY, MAY 4, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0435E
SUNSET: 1847E
MUCH NEEDED RAINFALL OVERNIGHT INTO TODAY; MUCH COOLER
AND WINDY….
A good slug of rainfall has fallen here at Blue Hill.
The rain started just after 10 P.M. last night and amounted
to 0.76″ through 7 A.M. this morning. An additional 0.09″
has fallen since 7 A.M. bringing the event total to 0.85″
so far.
The wind has been quite gusty here on the summit with a
peak gust of 37 mph having been recorded so far. The
average speed since 7 A.M. is around 15 mph.
Visibility has of course been quite limited by the rain
and fog, averaging only 1/4 to 1/2 mile through this morning,
but is starting to improve early this afternoon as drier
air begins to work into the area.
The high so far today is 48F, this is 15 degrees below the
normal high of 63F. The low since midnight is 44F, which
is equal to the daily normal low of 44F.
Today’s Observations:
7 A.M.
Weather: Sky obscured, vertical visibility 200 feet, light rain
Temperature: 44F; Dew Point: 44F; Relative Humidity: 100%
Wind: NE at 14G22 kts
Sea-level pressure: 29.78 in Hg, falling then rising
Visibility: 1/4 mile, fog
6-hr Max temp: 48F
6-hr Min temp: 44F
24-hr Precip: 0.76 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 X W2 1/4R-F 084/44/44/0314G22/978/ 8//// 53008
6055/ 70076 10048 20044
10 A.M.
Weather: Sky obscured, vertical visibility 300 feet, light drizzle
Temperature: 44F; Dew Point: 44F; Relative Humidity: 100%
Wind: NNE @ 15G28 kts, peak wind NNE 32 mph at 9:54 A.M.
Sea-level pressure: 29.80 in Hg; falling then rising
Visibility: 1/2 mile, fog
3-hr Precip: 0.06 ins.
3-hr Snow: 0.00 ins.
BHO SA 1455 X W3 1/2L-F 090/44/44/0315G28/980/ PK WND 0328/54/
8//// 53006 6006/
1 P.M.
Weather: Broken stratus fractus, overcast nimbostratus,
light drizzle, precipitation very light
Temperature: 45F, Dew point: 44F; Relative Humidity: 96%
Wind: NE @ 14G24 kts, peak wind NE 30 mph at 12:09 P.M.
Sea-level pressure: 29.82 in Hg; rising, then steady
Visibility: 20 miles, 6 miles SW, 50 miles NW-N
6-hr Max temp: 46F
6-hr Min temp: 44F
6-hr Precip: 0.09 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E2 BKN 10 OVC 20L- 099/45/44/0414G24/982/
PCPN VRY LGT VSBY 6 SW 50 NW-N PK WND 0426/09/ 8/6//
51009 6009/ 10046 20044
SUMMARY FOR MONDAY, MAY 3, 2021
TEMPERATURE (DEGREES F)
MAX…….67 NORMAL…..63
MIN…….48 NORMAL…..44
MEAN……58 NORMAL…..53
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….. +5
TOTAL DEPARTURE FOR THE MONTH………………..+11 [+3.5 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………… 7 DEPARTURE…….-5
TOTAL HEATING UNITS FOR THE MONTH……………25 DEPARTURE……-12
TOTAL HEATING UNITS FOR THE SEASON…………5366 DEPARTURE…..-706
TOTAL HEATING UNITS LAST SEASON TO DATE…….5537 DEPARTURE…..-171
COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0 DEPARTURE……. 0
TOTAL COOLING UNITS FOR THE MONTH…………… 0 DEPARTURE…….-1
TOTAL COOLING UNITS FOR THE SEASON………….. 0 DEPARTURE…….-3
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2 DEPARTURE…….-2
PEAK WIND GUST (MPH):
420C/Official…………..21 E @ 2:46 P.M.
AEROVANE (south tower)…..20 ESE @ 3:37 P.M.
ASOS…………………..20 ESE @ 2:40 P.M.
DAVIS #1……………….20 E @ 2:33 P.M.
DAVIS #2 (south tower)…..18 E @ 12:22 P.M.
RMY……………………20 @ 2:39 P.M.
VECTOR…………………21 @ 2:39 P.M.
MERLIN…………………N/A
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………13 E @ 2:50 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….14 E @ 3:03 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………15 E @ 2:35 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 ESE @ 6:29 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..14 SE @ 3:01 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..14 @ 2:24 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…… 8.0 ENE [191 total miles] ASOS………………… 8.5
DAVIS #1…………….. 8.5 ENE
DAVIS #2…………….. 8.4 ENE
RMY…………………. 8.0 E
VECTOR………………. 8.4
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.76 DEPARTURE….+0.64
ASOS………….0.74
TOTAL PRECIPITATION FOR THE MONTH………….0.83 DEPARTURE….+0.46
ASOS………….0.79
TOTAL PRECIPITATION FOR THE YEAR………….15.89 DEPARTURE….-3.03
ASOS………..16.07
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/0.0/415/52 31 NE AERO 30 NE RMY 33
04/14 56/42/49/+3/0.00/0.0/729/91 22 ESE AERO 23 ESE RMY 22
04/15 51/37/44/-3/0.30/0.0/016/02 26 ESE AERO 25 ESE RMY 28
04/16 39/31/35/-12/2.22/3.6/000/00 48 NNW AERO 58 NNW RMY 58
04/17 45/34/40/-7/0.07/T/040/05 27 NNW AERO 30 NNW RMY 29
04/18 60/38/49/+1/0.00/0.0/666/82 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/*T/…/.. 45 S AERO 51 S RMY 51 TSTM
04/22 44/28/36/-13/T/T/…/.. 54 W AERO 55 W RMY 59
04/23 58/32/45/-5/0.00/0.0/…/.. 47 W AERO 48 W RMY 52
04/24 70/44/57/+7/0.00/0.0/…/.. 33 WNW AERO 37 WNW RMY 55
04/25 54/44/49/-1/0.20/0.0/…/.. 23 NNE AERO 20 SSW RMY 24
04/26 55/40/48/-3/0.00/0.0/…/.. 39 NW AERO 40 NW RMY 43
04/27 67/38/53/+2/T/0.0/…/.. 26 W AERO 28 WNW RMY 28
04/28 63/46/55/+3/0.18/0.0/…/.. 18 ENE AERO 21 WNW RMY 20
04/29 54/44/48/-4/0.42/0.0/…/.. 18 ENE AERO 20 NNE RMY 19
04/30 62/41/52/0/0.08/0.0/…/.. 58 WNW AERO 60 WNW RMY 65
*Trace of frozen on 04/21 was hail, 1/8″ diameter, this does not
count as snowfall.
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 The low since midnight is 44F, the daily normal low is 44F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR MAY 4
HIGH 90F IN 2001
LOW 27F IN 1911 (RECORD FOR MAY)
PRECIP 1.67 INCHES IN 1893
SNOWFALL 0.1 INCHES IN 1920
PEAK GUST 60 MPH NW IN 1966
RECORDS FOR MAY 5
HIGH 92F IN 1949
LOW 30F IN 1891
PRECIP 2.74 INCHES IN 1922
SNOWFALL 3.0 INCHES IN 1917
PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976
TODAY’S REPORT PREPARED BY: Matt Douglas
