Friday, January 1, 2021

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

FRIDAY, JANUARY 1, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME

A QUIET AND COLD START TO THE NEW YEAR…

Happy New Year from all of us at Blue Hill Observatory!

Plenty of sunshine this morning is being replaced by
increasing high clouds this afternoon. Despite a good deal
of morning sunshine, temperatures have been rather
slow to rise so far today. We started the day in the mid
20s and have only recovered to the mid 30s by early afternoon.

This “cold” air mass is accompanied by high pressure that
has crested over the region mid to late this morning. The
barometer rose as high as 30.55 in/hg (~1035 millibars) this
morning, but is now in the process of falling as the center
of the high has passed.

Also indicative of high pressure overhead is the lack of wind.
Wind has only averaged around 4 MPH since 7 A.M. We even had
a period of calm wind during the mid morning period.

Visibility has been gradually increasing, starting the day at
around 50 miles, but has since risen to around 70 miles.

The high so far today is 35 degrees, which is equal to the
daily normal high of 35. The low since midnight is 25F, which
is 6 degrees above the daily normal low of 19F.

Today’s Observations:

7 A.M.
Weather: Thin scattered cirrus, few stratocumulus offshore
distant E-SE
Temperature: 26F; Dew Point: 21F; Relative Humidity: 81%
Wind: NW at 7 kts
Sea-level pressure: 30.50 in Hg; rising, then more rapidly
Visibility: 50 miles
6-hr Max temp: 28F
6-hr Min temp: 25F
24-hr Precip: Trace
24-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1155 300 -SCT 50 327/26/21/3207/050/ FEW SC OFFSHR DSNT E-SE/ 8/501 53023 70000 10028 20025

10 A.M.
Weather: Thin broken cirrus
Temperature: 31F; Dew Point: 20F; Relative Humidity: 63%
Wind: Calm
Sea-level pressure: 30.54 in Hg; steady, then rising
Visibility: 60 miles
3-hr Precip: Trace
3-hr Snow: 0.0 ins.
BHO SA 1455 E250 -BKN 60 341/31/20/0000/054/ WND CALM/ 8/001 53014

1 P.M.
Weather: Broken cirrostratus, overcast cirrus
Temperature: 35F, Dew point: 21F; Relative Humidity: 56%
Wind: SW at 2 kts, wind light and variable
Sea-level pressure: 30.45 inches Hg, falling, then more rapidly
Visibility: 70 miles
6-hr Max temp: 35F
6-hr Min temp: 26F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E200 BKN 250 OVC 70 311/35/21/2302/045/ THN K LYR WNW-NNE SUN DMLY VSBL WND L/V/ 8/006 58030 10035 20026

SUMMARY FOR THURSDAY, DECEMBER 31, 2020

TEMPERATURE (DEGREES F)
MAX…….44   NORMAL…..35
MIN…….28   NORMAL…..19
MEAN……36   NORMAL…..27

DEPARTURE FROM 30-YEAR NORMAL………………… +9
TOTAL DEPARTURE FOR THE MONTH…………………+84 [+2.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………29  DEPARTURE…… -9
TOTAL HEATING UNITS FOR THE MONTH…………..957  DEPARTURE……-86
TOTAL HEATING UNITS FOR THE SEASON…………1930  DEPARTURE…..-375
TOTAL HEATING UNITS LAST SEASON TO DATE…….2251  DEPARTURE…..-321

PEAK WIND GUST FOR YESTERDAY (MPH):
420C/Official…………..38 SW  @  2:46 A.M.
AEROVANE (south tower)…..43 SW  @  4:41 A.M.
ASOS…………………..40 SW  @  4:47 A.M.
DAVIS #1……………….39 SW  @  2:46 A.M.
DAVIS #2 (south tower)…..40 SW  @  4:46 A.M.
RMY……………………43     @  4:45 A.M.
VECTOR…………………45     @  4:47 A.M.
MERLIN…………………N/A

FASTEST MILE FOR YESTERDAY:
CONTACTING/OFFICIAL………………………..30 SW  @  3:10 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….28 SW  @  4:48 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………28 SW  @  3:11 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………29 SW  @  2:47 A.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..28 SW  @  2:45 A.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..29     @  2:44 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…14.9 NW  [358 total miles] ASOS………………15.0     [360 total miles] DAVIS #1…………..15.5 W   [372 total miles] DAVIS #2…………..15.9 W   [382 total miles] RMY……………….14.5 WNW [348 total miles] VECTOR…………….15.2     [365 total miles]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……Trace  DEPARTURE….-0.15
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….0.00  DEPARTURE….-0.15
ASOS………….0.00
TOTAL PRECIPITATION FOR THE YEAR…………..0.00  DEPARTURE….-0.15
ASOS…………0.00

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0  DEPARTURE…..-0.6
TOTAL SNOWFALL FOR THE MONTH……………… 0.0  DEPARTURE…..-0.6
TOTAL SNOWFALL FOR THE SEASON……………..26.2  DEPARTURE….+10.1

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   62/40/51/+14/0.61/0.0/112/20      60 S    AERO 67 W    RMY 64
12/02   42/32/37/+1/0.00/0.0/301/54       32 SW   AERO 32 SW   RMY 35
12/03   49/30/40/+4/0.00/0.0/512/92       25 SSW  AERO 25 SSW  RMY 28
12/04   58/40/49/+14/0.06/0.0/332/60      35 SSW  AERO 35 SSW  RMY 37
12/05   42/32/37/+2/2.13/2.8/000/00       58 NNW  AERO 58 NNW  RMY 67
12/06   34/26/30/-5/0.01/T/403/73        E44 WNW  AERO 44 WNW  RMY 49
12/07   33/22/28/-6/T/T/…/..            24 NW   AERO 26 NW   RMY 26
12/08   29/22/26/-8/T/T/…/..            24 NW   AERO 25 NW   RMY 28
12/09   34/19/27/-7/T/T/…/..            16 W    AERO 17 W    RMY 19
12/10   42/30/36/+3/0.00/0.0/…/..       30 WNW  AERO 31 WNW  RMY 29
12/11   50/31/41/+8/0.00/0.0/…/..       32 SW   AERO 35 SW   RMY 34
12/12   48/40/44/+11/0.38/0.0/…/..      25 E    AERO 21 E    RMY 25
12/13   58/35/47/+15/0.00/0.0…/..       28 W    AERO 31 WSW  RMY 31
12/14   35/30/33/+1/0.10/0.4/…/..       25 N    AERO 25 N    RMY 29
12/15   34/21/28/-4/0.00/0.0/…/..       32 WNW  AERO 33 WNW  RMY 38
12/16   27/13/20/-11/0.14/1.4/…/..      38 E    AERO 37 E    RMY 39
12/17   31/19/25/-6/1.58/15.1/…/..      55 ENE  AERO 56 ENE  RMY 59
12/18   27/18/23/-8/0.00/0.0/…/..       28 N    AERO 26 N    RMY 27
12/19   29/13/21/-9/0.00/0.0/…/..       16 SW   AERO 16 S    RMY 16
12/20   36/24/30/0/0.02/T/…/..          14 S    AERO 16 SW   RMY 14
12/21   34/29/32/+2/0.00/0.0/…/..       22 WNW  AERO 24 WNW  RMY 23
12/22   42/30/36/+7/0.00/0.0/…/…      34 WNW  AERO 35 WNW  RMY 38
12/23   37/26/32/+3/0.00/0.0/…/..       30 WNW  AERO 28 WNW  RMY 31
12/24   53/30/42/+13/T/0.0/…/..         46 SSE  AERO 50 SSE  RMY 55
12/25   61/37/49/+21/2.15/0.0/…/..      68 SSE  AERO 77 SSE  RMY 84
12/26   37/25/31/+3/0.00/0.0/…/..       38 SW   AERO 44 SW   RMY 43
12/27   38/22/30/+2/0.00/0.0/…/..       18 W    AERO 18 W    RMY 20
12/28   49/27/38/+10/T/0.0/…/..         35 SSW  AERO 36 –    RMY 37
12/29   38/20/29/+2/0.00/0.0/…/..       48 WNW  AERO 50 WNW  RMY 56
12/30   40/19/30/+3/0.00/0.0/…/..       39 SW   AERO 41 SW   RMY 45
12/31   44/28/36/+9/0.14/0.0/…/..       38 SW   AERO 43 SW   RMY 43

01/01 The low since midnight is 25F, the daily normal low is 19F

DAILY RECORDS FOR DECEMBER 2020
12/17/20: DAILY RECORD SNOWFALL OF 15.1 INCHES,
BREAKS PREVIOUS RECORD OF 7.5 INCHES SET IN 1988

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

RECORDS FOR JANUARY 1
HIGH 58F IN 1966
LOW -6F IN 1918
PRECIP 1.45 INS. IN 1982
SNOWFALL 7.2 INS. IN 1938
PEAK GUST 90e MPH S IN 1945

RECORDS FOR JANUARY 2
HIGH 62F IN 1890
LOW -7F IN 1899,1918
PRECIP 2.10 INS. IN 1987
SNOWFALL 9.0 INS. IN 1904
PEAK GUST 85e MPH S IN 1942

TODAY’S REPORT PREPARED BY: Matt Douglas