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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 7, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

EXCELLENT VISIBILITY WITH LITTLE CLOUD COVER
ATOP GREAT BLUE HILL....

We observed a perfect visibility of 90 miles at the
10 A.M. observation, with an average of 80 miles being
seen otherwise. Cloud cover differed greatly from 
yesterday's, where a 1/10th inch of snow fell in the
afternoon. Wind remained northwesterly, at speeds up
to 15 mph.  

Due in part to some cold air advection from the northwest, 
temperatures are below seasonal averages. The high so far 
today is 31F, which is 11 degrees below the daily normal 
maximum of 42F. The low since midnight is 21F, which is 
6 degrees below the normal minimum of 27F.

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: Scattered cirrostratus, few cumulus offshore
Temperature: 21F; Dew Point: 17F; Wind: NW at 10 kts 
Sea-level pressure: 30.24 ins. Hg, rising, then more slowly
Visibility: 80 miles
6-hr Max temp: 26F
6-hr Min temp: 21F
24-hr Precip:  0.02 ins.
24-hr Snowfall: 0.1 ins.
BHO SA 1155 250 SCT 80 242/21/17/3210/024/ FEW CU OFFSHR 
NEW SNOW PAST 24 HRS 0.1 INS/ 8/108 4/005 70002 51025 
10026 20021

10 A.M.
Weather: Clear, few cumulus and cirrostratus
Temperature: 26F; Dew Point: 14F; Wind: NW at 10G18 kts 
Sea-level pressure: 30.31 ins. Hg, rising, then more slowly
Visibility: 90 miles
3-hr Precip: 0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 CLR 90 262/26/14/3210G18/031/ FEW CU/CS ALQDS/ 
8/108 51020

1 P.M.
Weather: Clear, few cumulus and cirrostratus 
Temperature: 31F; Dew Point: 17F; Wind: NW at 12G17 kts
Sea-level pressure: 30.29 ins. Hg, falling steadily 
Visibility: 85 miles
6-hr Max temp: 31F
6-hr Min temp: 21F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 CLR 85 258/31/17/3112G17/029/ FEW CU/CS ALQDS/ 
8/108 4/005 58004 10031 20021


SUMMARY FOR FRIDAY, DECEMBER 6, 2019 

TEMPERATURE (DEGREES F)
MAX.....33   NORMAL.....42
MIN.....23   NORMAL.....27
MEAN....28   NORMAL.....35

DEPARTURE FROM 30-YEAR NORMAL..................... -7
TOTAL DEPARTURE FOR THE MONTH.....................-42 [-7.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............37  DEPARTURE........+7
TOTAL HEATING UNITS FOR THE MONTH..............218  DEPARTURE.......+41
TOTAL HEATING UNITS FOR THE SEASON............1455  DEPARTURE.......+17
TOTAL HEATING UNITS LAST SEASON TO DATE.......1496  DEPARTURE.......-41

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................25 NW  AT 10:14 P.M.  
                   AERO.........................23 NW  AT 10:14 P.M.   
                   ASOS.........................27 NW  AT 10:14 P.M. 
                   DAVIS........................27 NW  AT 10:12 P.M. RMY 29
FASTEST MILE FOR YESTERDAY......................19 NW  AT 10:15 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................18 NW  AT 10:15 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................19 NW  AT 10:14 P.M.
AVERAGE WIND SPEED AND DIRECTION..............10.0 W                   
                   ASOS.......................10.3  
                   DAVIS......................10.4 W [258 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.02  DEPARTURE......-0.14
                         ASOS..............0.02
TOTAL PRECIPITATION FOR THE MONTH..........2.45  DEPARTURE......+1.47
                         ASOS..............2.59
TOTAL PRECIPITATION FOR THE YEAR..........51.53  DEPARTURE......+2.01
                         ASOS.............51.99

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.1  DEPARTURE.......-0.3
TOTAL SNOWFALL FOR THE MONTH...............13.2  DEPARTURE......+11.5
TOTAL SNOWFALL FOR THE SEASON..............13.3  DEPARTURE.......+9.0


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  The low since midnight is 21F, daily normal minimum is 27F 


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 7
HIGH 74 IN 1998
LOW 6 IN 1906
PRECIP 1.67 INS. IN 1953
SNOWFALL 6.3 INS. IN 2003
PEAK GUST 76e SE IN 1976

RECORDS FOR DECEMBER 8
HIGH 62 IN 1966
LOW -4 IN 1906
PRECIP 1.54 INS. IN 1969
SNOWFALL 2.5 INS. IN 2001
PEAK GUST 78e W IN 1979

TODAY'S REPORT PREPARED BY: Benjamin Turner