Tuesday, December 21, 2021

BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

TUESDAY, DECEMBER 21, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0710E
SUNSET:  1615E

INCREASING CLOUDS AND NOT AS CHILLY….

The day started with plenty of sunshine, however high clouds have
been increasing and thickening as the day progresses. Despite this,
the temperature has been able to reach 40 degrees early this
afternoon, definitely a milder day than yesterday.

The dew point has been gradually increasing from the mid teens to
the mid 20s, indicative of the arctic air mass moving out of the
region.

Winds have been fairly light today, decreasing from around 12 mph
early this morning to only around 5-6 mph early this afternoon,
mainly out of a west-southwest direction.

Visibility hasn’t been as great as one would expect with the dry air
in place. Maximum visibility has only been 40 miles today, up from
30 miles early this morning.

The high so far today is 40F, which is 1 degree above the normal
max of 39F. The low since midnight is 27F, which is 3 degrees
above the normal low of 24F.

————————————————————–

Today’s Observations:

7 A.M.
Weather: Clear, few altocumulus N-E-SE, few cirrus all quadrants
Temperature: 28F; Dew Point: 17F; Relative Humidity: 63%
Wind: SW @ 10G17 kts
Sea-level pressure: 1018.1 mb; 30.06 in. Hg: rising then falling
Visibility: 30 miles, hazy
6-hr Max temp: 30F
6-hr Min temp: 27F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1155 CLR 30 181/28/17/2310G17/006/ FEW AC N-E-SE FEW CI ALQDS
HAZY/ 8/051 50009 10030 20027

10 A.M.
Weather: Thin broken cirrus, few cirrostratus distant W-NW
Temperature: 35F; Dew Point: 20F; Relative Humidity: 54%
Wind: WSW @ 7 kts
Sea-level pressure: 1019.8 mb; 30.11 in Hg; rising, then more slowly
Visibility: 40 miles, hazy
3-hr Precip: 0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 E250 -BKN 40 198/35/20/2407/011/ FEW CS DSNT W-NW HAZY/
8/005 51017

1 P.M.
Weather: Broken cirrostratus/cirrus
Temperature: 39F, Dew point: 25F; Relative Humidity: 56%
Wind: WSW @ 5 kts, wind light
Sea-level pressure: 1017.8 mb; 30.06 in Hg; falling, then more slowly
Visibility: 40 miles, hazy
6-hr Max temp: 40F
6-hr Min temp: 28F
6-hr Precip:   0.00 ins.
6-hr Snowfall: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1755 E250 BKN 40 178/39/25/2505/006/ HAZY WND LGT/ 8/006 56020
10040 20028

SUMMARY FOR MONDAY, DECEMBER 20, 2021

TEMPERATURE (DEGREES F)
MAX…….32     NORMAL…..39
MIN…….15     NORMAL…..24
MEAN……24     NORMAL…..31

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………… -7
TOTAL DEPARTURE FOR THE MONTH………………………+89 [+4.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2021 THRU JUN 2022)
TOTAL HEATING UNITS FOR YESTERDAY……………41  DEPARTURE……..+7
TOTAL HEATING UNITS FOR THE MONTH…………..530  DEPARTURE…….-89
TOTAL HEATING UNITS FOR THE SEASON…………1537  DEPARTURE……-286
TOTAL HEATING UNITS LAST SEASON TO DATE…….1600 DEPARTURE……..-63

PEAK WIND GUST (MPH):
Official (1-Sec AVG)…….29 SSW @  9:52 P.M.
AEROVANE……………….30 SSW @  9:54 P.M.
VECTOR #2 (Instantaneous)..30     @  9:52 P.M.
DAVIS #2 ………………28 SW  @ 11:30 P.M.
RMY #2 (Instantaneous)…..30 SW  @  9:52 P.M.
ASOS………..OUT OF SERVICE D/T RENOVATIONS
VECTOR #1……OUT OF SERVICE D/T RENOVATIONS
DAVIS #1…….OUT OF SERVICE D/T RENOVATIONS
RMY #1………OUT OF SERVICE D/T RENOVATIONS
MERLIN………OUT OF SERVICE D/T RENOVATIONS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………22 SSW @ 11:29 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..21     @  9:53 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………21 SW  @  9:53 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..21 SW  @  9:53 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE…….OUT OF SERVICE D/T RENOVATIONS
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE…OUT OF SERVICE D/T RENOVATIONS
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE..OUT OF SERVICE D/T RENOVATIONS
MAXIMUM 2-MINUTE RMY #1 AVERAGE…..OUT OF SERVICE D/T RENOVATIONS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…..10.1 NNW  [242 total miles] VECTOR #2……………10.6
DAVIS #2…………….10.5 W
RMY #2………………10.7 W
RMY #1…………..OUT OF SERVICE D/T RENOVATIONS
ASOS…………….OUT OF SERVICE D/T RENOVATIONS
VECTOR #1………..OUT OF SERVICE D/T RENOVATIONS
DAVIS #1…………OUT OF SERVICE D/T RENOVATIONS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00  DEPARTURE…..-0.17
TOTAL PRECIPITATION FOR THE MONTH………….1.95  DEPARTURE…..-1.61
TOTAL PRECIPITATION FOR THE YEAR………….58.72  DEPARTURE…..+6.95

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M………….0.0  DEPARTURE……-0.5
TOTAL SNOWFALL FOR THE MONTH……………….1.4  DEPARTURE……-5.7
TOTAL SNOWFALL FOR THE SEASON (2021-2022)……2.4  DEPARTURE……-7.2

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 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

12/01   44/30/37/0.00/0.0/263/47          35 W   AERO 35 W   RMY 34
12/02   58/35/47/10/T/0.0/106/19          56 WNW AERO 59 WNW RMY 62 TSTM
12/03   41/28/35/-1/0.00/0.0/512/92       46 NW  AERO 44 NW  RMY 46
12/04   39/25/32/-4/0.00/0.0/233/42       25 SW  AERO 23 SW  RMY 26
12/05   45/32/39/+3/0.00/0.0/460/83       25 SE  AERO 25 SE  RMY 25
12/06   59/37/48/+13/0.34/0.0/077/14      59 WNW AERO 59 NW  RMY 60
12/07   40/29/35/0/T/0.0/436/79           47 WNW AERO 36 WNW RMY 48
12/08   34/25/30/-5/0.05/0.6/000/00       26 NNE AERO 25 NE  RMY 26
12/09   35/20/28/-6/0.05/0.6/319/58       32 NW  AERO 30 NW  RMY 33
12/10   43/27/35/+1/0.00/0.0/000/00       21 SE  AERO 20 SE  RMY 21
12/11   62/37/50/+16/0.34/0.0/000/00      57 SSW AERO 59 SSW RMY 58
12/12   58/36/47/+13/0.05/0.0/416/76      55 WNW AERO 55 WNW RMY 58
12/13   50/35/43/+10/0.00/0.0/224/41      32 WSW AERO 33 WSW RMY 33
12/14   50/33/42/+9/0.00/0.0/442/81       31 WSW AERO 30 WSW RMY 32
12/15   42/28/35/+2/T/0.0/153/28          35 SSE AERO 35 SSE RMY 36
12/16   58/42/50/+18/0.21/0.0/016/03      35 SW  AERO 37 SW  RMY 38
12/17   56/39/48/+16/0.00/0.0/518/95      43 WNW AERO 41 WNW RMY 46
12/18   39/31/35/+3/0.52/0.2/000/00       21 NNW AERO 20 NNW RMY 20
12/19   39/20/30/-2/0.39/0.0/…/..       35 NNW AERO 37 NNW RMY 36
12/20   32/15/24/-7/0.00/0.0/…/..       29 SSW AERO 30 SSW RMY 30

12/21 The low since midnight is 27F, the daily normal low is 24F

DAILY RECORDS FOR DECEMBER 2021

12/16/21: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 42F
TIES PREVIOUS RECORD of 42F SET IN 1982

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)

RECORDS FOR DECEMBER 21
HIGH 62 IN 2018
LOW -10 IN 1942
PRECIP 2.37 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957

RECORDS FOR DECEMBER 22
HIGH 63 IN 2013
LOW -5 IN 1921
PRECIP 1.52 INS. IN 1975
SNOWFALL 8.8 INS. IN 1975
PEAK GUST 62 MPH WNW IN 1998

TODAY’S REPORT PREPARED BY: Matt Douglas