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

MONDAY, JANUARY 11, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0712E
SUNSET:  1633E

OVERCAST AND CHILLY, BUT QUIET TODAY ON THE HILL....

High clouds this morning have lowered to mid level clouds
early this afternoon. The sun has been dimly visible through
the clouds, but not enough to render a burn on our sun card
so far today.

Wind has been quite light today, generally steady at around
8 mph. High pressure over the region is the culprit for the
"dull" weather.

An inversion has been over the region all day. A thin smoke
layer trapped under this inversion has been visible since
mid morning. Our visibility started the day at around 55
miles, then jumped up to 80 miles above the inversion. It has
since dropped back to 40 miles as the level of the inversion
increased and allowed the hazy/smoke layer to rise obscuring
the views of both Mt Wachusett and Mt Monadnock to the WNW
and NW respectively.

The inversion is also holding temperatures down a bit today,
the high so far today is only 33F, 1 degree lower than the 
daily normal maximum of 34F. The low since midnight is 25F,
8 degrees above the normal minimum of 17F. 


PRELIMINARY STATS FOR DECEMBER 2020

TEMPERATURE, Deg. F
Avg. Max. 41.1 [+2.0]
Avg. Min. 27.2 [+3.6]
Mean      34.2 [+2.9]
24-hour corrected mean: 34.0
Max. for month: 62F on the 1st
Min. for month: 13F on the 16th and 19th

HEATING DEGREE DAYS
Total heating units:   957 [-86]
Total for the season:  1930 [-375]
Total for last season: 2251

PRECIPITATION, Inches
Total: 7.32 [+2.43]
Greatest in 24 hrs: 2.15 ins. on the 25th 

SNOWFALL, Inches
Total: 19.7 [+6.3]
Greatest in 24 hrs: 16.5 ins. on the 16th-17th

WIND, mph
Avg. uncorrected wind speed: 13.0 mph
Avg. corrected wind speed:   13.3 mph
Prevailing wind direction:   WNW [17%]
Peak gust and direction:     68 SSE on the 25th

SUNSHINE:
Campbell-Stokes card minutes: 6756 minutes of a possible 16470 or 41%
Astronomical total minutes: 6961 minutes of a possible 16991 or 41%



Today's Observations:

7 A.M.
Weather: Broken cirrus
Temperature: 27F; Dew Point: 14F; Relative Humidity: 58%
Wind: SW at 7 kts
Sea-level pressure: 30.30 in Hg; rising, then more rapidly
Visibility: 55 miles
6-hr Max temp: 28F
6-hr Min temp: 25F
24-hr Precip: 0.00 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1155 E250 BKN 55 262/27/14/2207/030/ 8/001 53008 10028 20025 

10 A.M.
Weather: Overcast cirrostratus, thin smoke layer along horizon
all quadrants
Temperature: 30F; Dew Point: 15F; Relative Humidity: 53%
Wind: SW at 6 kts
Sea-level pressure: 30.28 in Hg; falling, then more rapidly
Visibility: 80 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 E180 OVC 80 253/30/15/2206/028/ THN K LYR ALNG HRZN ALQDS SUN DMLY VSBL/ 8/007 58009

1 P.M.
Weather: Overcast altostratus, thin smoke layer all quadrants
Temperature: 33F, Dew point: 19F; Relative Humidity: 56%
Wind: WSW at 7 kts
Sea-level pressure: 30.20 inches Hg, falling, then more rapidly
Visibility: 40 miles, hazy
6-hr Max temp: 33F
6-hr Min temp: 27F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E130 OVC 40 228/33/19/2407/020/ THN K LYR ALQDS SUN DMLY VSBL HAZY/ 8/01/ 58025 10033 20027


SUMMARY FOR SUNDAY, JANUARY 10, 2021

TEMPERATURE (DEGREES F)
MAX.......39   NORMAL.....34
MIN.......24   NORMAL.....17
MEAN......32   NORMAL.....25

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL........+7
TOTAL DEPARTURE FOR THE MONTH...................+57 [+5.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............33  DEPARTURE.......-7
TOTAL HEATING UNITS FOR THE MONTH..............332  DEPARTURE......-57
TOTAL HEATING UNITS FOR THE SEASON............2262  DEPARTURE.....-431
TOTAL HEATING UNITS LAST SEASON TO DATE.......2564  DEPARTURE.....-302

PEAK WIND GUST (MPH):
                     420C/Official..............25 NNW  @  2:43 A.M.
                     AEROVANE (south tower).....23 NNW  @  2:43 A.M. 
                     ASOS.......................23 NNW  @  2:43 A.M.
                     DAVIS #1...................23 NNW  @  2:43 A.M.
                     DAVIS #2 (south tower).....24 N    @  2:43 A.M.
                     RMY........................24      @  2:42 A.M.
                     VECTOR.....................25      @  2:46 A.M. 
                     MERLIN.....................N/A

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL..................16 NNW @  2:44 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE...................16 NNW @  6:50 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE...............17 NW  @  2:43 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE...............18 NNW @  2:44 A.M.
MAXIMUM 2-MINUTE RMY AVERAGE....................16 NNW @  6:47 A.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE.................16     @  2:40 A.M.

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL... 9.0 NW  [215 total miles]
                     ASOS.................. 9.7     [233 total miles]
                     DAVIS #1.............. 9.6 NNW [230 total miles]
                     DAVIS #2.............. 9.5 NNW [228 total miles]
                     RMY................... 9.1 NNW [218 total miles]
                     VECTOR................ 9.5     [228 total miles]


PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.......0.00  DEPARTURE....-0.14
                             ASOS.............0.00
TOTAL PRECIPITATION FOR THE MONTH.............0.49  DEPARTURE....-0.93
                             ASOS.............0.48
TOTAL PRECIPITATION FOR THE YEAR..............0.49  DEPARTURE....-0.93
                              ASOS............0.48

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M...........0.0  DEPARTURE.....-0.6
TOTAL SNOWFALL FOR THE MONTH.................. 1.9  DEPARTURE.....-3.8
TOTAL SNOWFALL FOR THE SEASON.................28.1  DEPARTURE.....+6.4


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/+14/0.61/0.0/112/20      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/457/83            24 NW   AERO 26 NW   RMY 26
12/08   29/22/26/-8/T/T/006/01            24 NW   AERO 25 NW   RMY 28
12/09   34/19/27/-7/T/T/000/00            16 W    AERO 17 W    RMY 19
12/10   42/30/36/+3/0.00/0.0/351/64       30 WNW  AERO 31 WNW  RMY 29
12/11   50/31/41/+8/0.00/0.0/384/70       32 SW   AERO 35 SW   RMY 34
12/12   48/40/44/+11/0.38/0.0/000/00      25 E    AERO 21 E    RMY 25
12/13   58/35/47/+15/0.00/0.0/109/20      28 W    AERO 31 WSW  RMY 31
12/14   35/30/33/+1/0.10/0.4/000/00       25 N    AERO 25 N    RMY 29
12/15   34/21/28/-4/0.00/0.0/541/99       32 WNW  AERO 33 WNW  RMY 38
12/16   27/13/20/-11/0.14/1.4/180/33      38 E    AERO 37 E    RMY 39
12/17   31/19/25/-6/1.58/15.1/000/00      55 ENE  AERO 56 ENE  RMY 59
12/18   27/18/23/-8/0.00/0.0/120/22       28 N    AERO 26 N    RMY 27
12/19   29/13/21/-9/0.00/0.0/436/80       16 SW   AERO 16 S    RMY 16
12/20   36/24/30/0/0.02/T/000/00          14 S    AERO 16 SW   RMY 14
12/21   34/29/32/+2/0.00/0.0/000/00       22 WNW  AERO 24 WNW  RMY 23
12/22   42/30/36/+7/0.00/0.0/447/82       34 WNW  AERO 35 WNW  RMY 38
12/23   37/26/32/+3/0.00/0.0/480/88       30 WNW  AERO 28 WNW  RMY 31
12/24   53/30/42/+13/T/0.0/153/28         46 SSE  AERO 50 SSE  RMY 55
12/25   61/37/49/+21/2.15/0.0/000/00      68 SSE  AERO 77 SSE  RMY 84
12/26   37/25/31/+3/0.00/0.0/485/89       38 SW   AERO 44 SW   RMY 43
12/27   38/22/30/+2/0.00/0.0/513/94       18 W    AERO 18 W    RMY 20
12/28   49/27/38/+10/T/0.0/109/20         35 SSW  AERO 36 -    RMY 37
12/29   38/20/29/+2/0.00/0.0/470/86       48 WNW  AERO 50 WNW  RMY 56
12/30   40/19/30/+3/0.00/0.0/060/11       39 SW   AERO 41 SW   RMY 45
12/31   44/28/36/+9/0.14/0.0/000/00       38 SW   AERO 43 SW   RMY 43

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
12/25/20: DAILY RECORD PRECIPITATION OF 2.15 INCHES,
          BREAKS PREVIOUS RECORD OF 1.37 INCHES SET IN 2002


PRELIMINARY CLIMATE SUMMARY FOR JANUARY 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

01/01   36/25/31/+4/0.06/0.3/.../..       23 E    AERO 23 NNW  RMY 23
01/02   43/30/37/+10/0.30/T/.../..        37 WNW  AERO 39 WNW  RMY 44
01/03   33/27/30/+4/0.07/0.8/.../..       23 NNE  AERO 22 NNE  RMY 25
01/04   37/28/33/+7/0.01/0.1/.../..       25 NNE  AERO 23 NNE  RMY 27
01/05   31/28/30/+4/0.05/0.7/.../..       21 NNW  AERO 21 NNW  RMY 22
01/06   38/28/33/+7/T/T/.../..            30 NW   AERO 29 NW   RMY 32
01/07   42/26/34/+8/0.00/0.0/.../..       28 NNW  AERO 26 NNW  RMY 31
01/08   40/21/31/+5/0.00/0.0/.../..       25 NNW  AERO 22 NNW  RMY 25
01/09   34/30/27/+1/0.00/0.0/.../..       25 N    AERO 23 N    RMY 24
01/10   39/24/32/+7/0.00/0.0/.../..       25 NNW  AERO 23 NNW  RMY 24

01/11 The low since midnight is 25F, the daily normal low is 17F


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

RECORDS FOR JANUARY 11
HIGH 65F IN 2020 
LOW -7F IN 1968
PRECIP 1.58 INS. IN 2008
SNOW 10.2 INS. 1927
PEAK GUST 95e MPH S IN 1980

RECORDS FOR JANUARY 12
HIGH 68F IN 2020 [RECORD FOR MONTH]
LOW -15F IN 1886
PRECIP 2.04 INS. IN 2011
SNOW 18.2 INS. IN 2011
WIND 84e MPH S IN 1980

TODAY'S REPORT PREPARED BY: Matt Douglas