Sunday, December 27, 2020

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

SUNDAY, DECEMBER 27, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

DRY AFTERNOON WITH CONTINUED SUNSHINE….

It was a cool but more seasonable start to the morning, with a low of 22F around the 7:00 P.M. EST observation. This is only 2F above the normal low of 20F for December 27th. By the 1:00 P.M. observation, the temperature rose to 38F which is also only 2F above normal. The dew point stayed around 18F, giving a relative humidity of 82% in the morning. By 1:00 P.M., the relative humidity dropped down to only 44%, giving us drier conditions than previous days.

Despite the lower visibility in the morning at only 40 miles, skies were mostly clear. More cirrus clouds moved in by 1:00 P.M, but they were thin enough for the sun to still shine brightly and the visibility increased to 70 miles. Pressure continued to increase from yesterday, and with light winds, it was a very pleasant afternoon at Great Blue Hill.

Today’s Observations:

7 A.M.
Weather: Clear, few distant stratocumulus northeast to east
Temperature: 22F; Dew Point: 18F; Relative Humidity: 82%
Wind: WSW @ 10 kts
Sea-level pressure: 30.18 in Hg; rising steadily
Visibility: 40 miles, distant haze in all directions
6-hr Max temp: 24F
6-hr Min temp: 22F
24-hr Precip: 0.0 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1155 CLR 40 219/22/18/2510/018/ FEW DSNT SC NE-E DSNT HZ ALQDS/ 8/500 52036 10024 20022

10 A.M.
Weather: Clear, few cirrus southeast to south
Temperature: 30F; Dew Point: 18F; Relative Humidity: 62%
Wind: W @ 6 kts,
Wind speed: Light
Sea-level pressure: 30.26 in Hg; rising, then rising less quickly
Visibility: 40 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 CLR 40 248/30/18/2706/026/ FEW CI SE-S DSNT HZ ALQDS WND LGT/ 8/001 51029

1 P.M.
Weather: Scattered cirrus, few cumulus northwest
Temperature: 38F, Dew point: 18F; Relative Humidity: 44%
Wind: SW at 5 kts,
Wind speed: Light
Sea-level pressure: 30.26 inches Hg, steady, then falling
Visibility: 70 miles
6-hour max. temp: 38F
BH0 SA 1755 250 SCT 70 246/38/18/2305/026/ FEW CU NW WND LGT/ 8/101 58002 10038 20022

SUMMARY FOR SATURDAY, DECEMBER 26, 2020

TEMPERATURE (DEGREES F)
MAX…….37   NORMAL…..36
MIN…….25   NORMAL…..20
MEAN……31   NORMAL…..28

DEPARTURE FROM 30-YEAR NORMAL………………….+3
TOTAL DEPARTURE FOR THE MONTH…………………+58 [+2.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………34  DEPARTURE…….-3
TOTAL HEATING UNITS FOR THE MONTH…………..765  DEPARTURE……-60
TOTAL HEATING UNITS FOR THE SEASON…………1768  DEPARTURE…..-349
TOTAL HEATING UNITS LAST SEASON TO DATE…….2109  DEPARTURE…..-341

PEAK WIND GUST FOR YESTERDAY (MPH):
420C/Official…………..38 SW  @ 12:56 A.M.
AEROVANE (south tower)…..44 SW  @ 12:25 A.M.
ASOS…………………..41 SW  @ 12:56 A.M.
DAVIS #1……………….40 N/A @ 12:08 A.M.
DAVIS #2 (south tower)…..40 SW  @ 12:00 A.M.
RMY……………………43.0
VECTOR…………………44.6
MERLIN…………………N/A

FASTEST MILE FOR YESTERDAY:
CONTACTING/OFFICIAL………………………..32 SW  @ 12:31 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….30 SW  @ 12:28 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………31 N/A @ 12:28 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………32 SW  @ 12:28 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…14.5 WSW [349 total miles] ASOS………………14.7     [353 total miles] DAVIS #1…………..14.9 W   [358 total miles] DAVIS #2…………..15.0 WSW [360 total miles] RMY……………….13.9 WSW [334 total miles] VECTOR…………….14.4     [286 total miles]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00  DEPARTURE….-0.16
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….7.18  DEPARTURE….+3.00
ASOS………….7.77
TOTAL PRECIPITATION FOR THE YEAR………….53.58  DEPARTURE….+0.87
ASOS………..55.10

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0  DEPARTURE…..-0.5
TOTAL SNOWFALL FOR THE MONTH………………19.7  DEPARTURE…..+9.0
TOTAL SNOWFALL FOR THE SEASON……………..26.2  DEPARTURE….+13.4

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/…/..      60 S    AERO 67 W    RMY 64
12/02   42/32/37/+1/0.00/0.0/…/..       32 SW   AERO 32 SW   RMY 35
12/03   49/30/40/+4/0.00/0.0/…/..       25 SSW  AERO 25 SSW  RMY 28
12/04   58/40/49/+14/0.06/0.0/…/..      35 SSW  AERO 35 SSW  RMY 37
12/05   42/32/37/+2/2.13/2.8/…/..       58 NNW  AERO 58 NNW  RMY 67
12/06   34/26/30/-5/0.01/T/…/..        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/…./1.4/…/..      38 E    AERO 37 E    RMY 39
12/17   31/19/25/-6/…./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/…./…/…/..      46 SSE  AERO 50 SSE  RMY 55
12/25   61/37/49/+21/…./…/…/..      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 The low since midnight is 22F, the daily normal low is 20F

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 DECEMBER 27
HIGH 57 IN 1895,1949
LOW -4 IN 1903
PRECIP 2.43 INS. IN 1969
SNOWFALL 11.2 INS. IN 1947
PEAK GUST 73 S IN 2011

RECORDS FOR DECEMBER 28
HIGH 60 IN 1982
LOW -2 IN 1933
PRECIP 2.16 INS. IN 1967
SNOWFALL 9.5 INS. IN 1967
PEAK GUST 89 MPH SSE IN 1983

TODAY’S REPORT PREPARED BY: Lizzy Suzedell