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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, DECEMBER 11, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

A SNOWY MORNING LEADS TO SOME AFTERNOON SUNSHINE
ATOP GREAT BLUE HILL....

Today we measured 3.0 inches of snow at 7 A.M., with an 
additional 1.8 inches by 1 P.M. Melted precipitation 
amounted to .56 inches, with an additional .13 inches
falling by noon. Snow began this morning around 2 A.M.,
and stopped before 11:30 A.M. Wind has been light all 
day, coming in from the west. Visibility increased from 
a half mile this morning to almost 80 miles by 2 P.M.

Snow this month has amounted to 16.2 inches, which is 
13.0 inches above normal for the first third of 
December.   

The high so far today is 32F, which is 9 degrees below 
the daily normal maximum of 41F. The low since midnight 
is 27F, which is 2 degrees above the normal minimum of 25F.


PRELIMINARY STATS FOR NOVEMBER 2019

TEMPERATURE, Deg. F
Avg. Max. 46.0 [-4.0]
Avg. Min. 30.3 [-3.2]
Mean      38.2 [-3.5]
24-hour corrected mean: 38.0
Max. for month: 67F on the 1st
Min. for month: 15F on the 13th

HEATING DEGREE DAYS
Total heating units:    761 [+99]
Total for the season:  1237 [-24]
Total for last season: 1319

PRECIPITATION, Inches
Total: 3.74 [-1.02]
Greatest in 24 hrs: N/A 

SNOWFALL, Inches
Total: 0.1 [-2.2]
Greatest in 24 hrs: 0.1 ins. on the 12th

WIND, mph
Avg. uncorrected wind speed: 12.5 mph
Avg. corrected wind speed:   12.9 mph
Prevailing wind direction:   W [16%]
Peak gust and direction:     67 S on the 1st

SUNSHINE:
Campbell-Stokes card minutes: 8652 minutes of possible 17010 or 51%
Astronomical total minutes: 8985 minutes of possible 17640 or 51%

Today's Observations:

7 A.M.
Weather: Snow
Temperature: 27F; Dew Point: 27F; Wind: WNW at 14G19 kts 
Sea-level pressure: 30.18 ins. Hg, rising, then more slowly
Visibility: 1/2 mile
6-hr Max temp: 36F
6-hr Min temp: 27F
24-hr Precip:  0.56 ins.
24-hr Snowfall: 3.0 ins.
BHO SA 1155 X W3 1/2S 221/27/27/3014G19/018/ SCTD NEW SNOW 
PAST 24 HOURS 3.0 INS. / 8//// 4/003 70056 53023 10036 20027

10 A.M.
Weather: Light snow
Temperature: 27F; Dew Point: 27F; Wind: W at 6 kts,
Wind: Light 
Sea-level pressure: 30.24 ins. Hg, falling, then rising
Visibility: 1 mile
3-hr Precip: 0.11 ins.
3-hr Snowfall: 1.1 ins.
BHO SA 1455 E35 OVC 1S- 239/27/27/2706/024/ S-CTD NEW SNOW 
PAST 3 HOURS 1.1 INS. WND LGT/ 8/6// 51018

1 P.M.
Weather: Broken stratocumulus 
Temperature: 31F; Dew Point: 29F; Wind: WSW at 6 kts,
Wind: Light
Sea-level pressure: 30.18 ins. Hg, falling, then more slowly
Visibility: 75 miles
6-hr Max temp: 32F
6-hr Min temp: 27F
6-hr Precip:  0.13 ins.
6-hr Snowfall: 1.8 ins.
BHO SA 1755 E30 BKN 75 219/31/29/2506/018/ NEW SNOW PAST 6 
HOURS 1.8 INS. WND LGT/ 8/400 4/004 6013/ 58020 10032 20027


SUMMARY FOR TUESDAY, DECEMBER 10, 2019 

TEMPERATURE (DEGREES F)
MAX.....58   NORMAL.....41
MIN.....37   NORMAL.....26
MEAN....48   NORMAL.....33

DEPARTURE FROM 30-YEAR NORMAL.....................+15
TOTAL DEPARTURE FOR THE MONTH.....................-31 [-3.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............17  DEPARTURE.......-15
TOTAL HEATING UNITS FOR THE MONTH..............332  DEPARTURE.......+31
TOTAL HEATING UNITS FOR THE SEASON............1569  DEPARTURE........+7
TOTAL HEATING UNITS LAST SEASON TO DATE.......1651  DEPARTURE.......-82

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................35 SW  AT 12:07 A.M.  
                   AERO.........................39 SW  AT 12:04 A.M.   
                   ASOS.........................39 SSW AT 12:06 A.M. 
                   DAVIS........................36 SW  AT 12:02 A.M. RMY 33
FASTEST MILE FOR YESTERDAY......................27 SW  AT 12:04 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................28 SSW AT 12:09 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................27 SSW AT 12:06 A.M.
AVERAGE WIND SPEED AND DIRECTION..............17.3 SW                   
                   ASOS.......................16.6  
                   DAVIS......................16.5 SSW  [232 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.56  DEPARTURE......+0.39
                         ASOS..............0.52
TOTAL PRECIPITATION FOR THE MONTH..........3.68  DEPARTURE......+2.03
                         ASOS..............3.97
TOTAL PRECIPITATION FOR THE YEAR..........52.76  DEPARTURE......+2.57
                         ASOS.............53.37

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........3.0  DEPARTURE.......+2.6
TOTAL SNOWFALL FOR THE MONTH...............16.2  DEPARTURE......+13.0
TOTAL SNOWFALL FOR THE SEASON..............16.3  DEPARTURE......+10.5


PRELIMINARY CLIMATE SUMMARY FOR NOVEMBER 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

11/01  67/35/51/+5/0.12/0.0/534/86            67 S   AERO M  M   RMY N/A
11/02  50/31/41/-5/0.00/0.0/612/99            17 WNW AERO 14 W   RMY N/A
11/03  53/35/44/-2/0.00/0.0/567/92            25 WSW AERO 23 W   RMY 26
11/04  53/33/43/-2/0.00/0.0/546/89            24 S   AERO 20 S   RMY 24
11/05  54/44/49/+4/0.33/0.0/000/00            22 S   AERO 18 WNW RMY 28
11/06  51/36/44/-1/0.00/0.0/596/98            28 WSW AERO 23 W   RMY 27
11/07  55/38/47/+2/0.27/0.0/000/00            30 S   AERO 26 SSW RMY 32
11/08  38/23/31/-13/0.00/0.0/555/92           38 NW  AERO 37 WNW RMY 44   
11/09  39/20/30/-14/0.00/0.0/583/97           22 S   AERO 18 S   RMY N/A
11/10  51/30/41/-3/0.00/0.0/174/29            30 SW  AERO 30 SW  RMY 31
11/11  52/39/46/+3/T/0.0/000/00               23 NE  AERO 22 NE  RMY 23
11/12  42/20/31/-12/0.08/0.1/000/00           37 WNW AERO 37 WNW RMY 41
11/13  28/15/22/-21/0.00/0.0/592/100          32 WNW AERO 32 WNW RMY 35
11/14  36/17/28/-14/0.00/0.0/136/23           18 SW  AERO 17 SW  RMY 20 
11/15  51/32/42/0/0.00/0.0/553/94             25 WNW AERO 25 WNW RMY N/A
11/16  35/22/29/-13/0.00/0.0/580/99           35 NNW AERO 35 NNW RMY N/A
11/17  40/21/31/-10/T/T/000/00                28 ENE AERO 27 ENE RMY 29
11/18  36/32/34/-7/..../0.0/000/00            28 NNE AERO 29 N   RMY 31
11/19  42/36/39/-2/..../0.0/000/00            12 SSW AERO  9 NNW RMY N/A
11/20  38/33/36/-4/..../T/000/00              20 NW  AERO 18 NW  RMY 21
11/21  46/30/38/-2/0.00/0.0/536/93            21 NW  AERO 21 NW  RMY N/A
11/22  52/32/42/+2/0.12/0.0/000/00            46 W   AERO 47 W   RMY 47
11/23  44/27/36/-3/0.00/0.0/503/88            29 WNW AERO 29 WNW RMY N/A
11/24  44/35/40/+1/1.49/0.0/000/00            45 N   AERO 44 NE  RMY 46 TSTM
11/25  50/34/42/+3/0.00/0.0/329/58            32 WNW AERO 35 WNW RMY 23
11/26  59/39/49/+11/0.00/0.0/544/96           28 SSW AERO 27 SSW RMY 29
11/27  50/42/46/+8/..../0.0/011/02            30 W   AERO 32 W   RMY N/A TSTM
11/28  48/30/39/+1/..../T/062/11              42 NW  AERO 44 NW  RMY 44
11/29  39/27/33/-4/0.00/0.0/433/77            35 NW  AERO 36 NW  RMY 39
11/30  35/22/29/-8/0.00/0.0/539/96            30 NW  AERO 28 WNW RMY 31

DAILY RECORDS FOR NOVEMBER

11/13/19: DAILY RECORD LOW MAXIMUM TEMPERATURE OF 28F,
          BREAKS PREVIOUS RECORD OF 30F SET IN 1920.
          It was also the third earliest maximum temperature 
          colder than 30F on record, behind only 28F on 11/8/1894 
          and 29F on 11/12/1894.

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  32/16/24/-13/..../5.8/.../..           33 ENE AERO 32 ENE RMY N/A
12/02  37/25/31/-5/..../2.7/.../..            52 NE  AERO 47 NE  RMY 53
12/03  30/23/27/-9/..../4.6/.../..            32 N   AERO 35 N   RMY 36
12/04  34/22/28/-7/..../0.0/.../..            23 WNW AERO 23 NNW RMY N/A
12/05  41/26/34/-1/..../0.0/.../..            33 NW  AERO 35 NW  RMY 37
12/06  33/23/28/-7/0.02/0.1/.../..            25 NW  AERO 23 NW  RMY 29
12/07  31/18/25/-9/0.00/0.0/.../..            25 NW  AERO 23 NW  RMY N/A
12/08  36/15/26/-8/0.00/0.0/.../..            31 SSW AERO 32 SSW RMY N/A
12/09  57/36/47/+13/..../0.0/.../..           53 S   AERO 52 S   RMY 54
12/10  58/37/48/+15/..../0.0/.../..           35 SW  AERO 39 SW  RMY N/A

12/11 The low since midnight is 27F, daily normal minimum is 25F 


DAILY RECORDS FOR DECEMBER

12/01/19: DAILY RECORD SNOWFALL OF 5.8 INS.,
          BREAKS PREVIOUS RECORD OF 2.0 INS. SET IN 1902.

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

RECORDS FOR DECEMBER 11
HIGH 63 IN 1911
LOW -1 IN 1988
PRECIP 2.36 INS. IN 1992
SNOWFALL 6.0 INS. IN 1894
PEAK GUST 78 S IN 1969

RECORDS FOR DECEMBER 12
HIGH 67 IN 1979
LOW -3 IN 1988
PRECIP 3.94 INS. IN 1992
SNOWFALL 20.3 INS. IN 1960
PEAK GUST 75 MPH SSE IN 2008

TODAY'S REPORT PREPARED BY: Benjamin Turner and Greg White