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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, DECEMBER 16, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

COLD AND CLOUDY HAVE BEEN THE THEME FOR TODAY....

We've had a mostly cloudy sky today as a storm system
develops to our southwest. A cold air mass has moved 
into the region as indicated by low dew points in the 
low teens today. As a result of the very dry arctic 
air, visibility has been excellent reaching 80 miles.

After a couple of days above normal, today has returned 
to the theme of below normal temperatures. The high so
far today is 30F, which is 9 degrees below the daily
normal maximum of 39F. The low since midnight is 25F, 
which is 1 degree above the normal minimum of 24F.


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: 1.60 ins. on the 24th

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, thin broken cirrus 
Temperature: 26F; Dew Point: 12F; Wind: WNW at 10 kts
Sea-level pressure: 30.18 ins. Hg, rising, then more slowly
Visibility: 70 miles
24-hr Precip: 0.00 ins.
24-hr Snowfall: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1155 200 SCT E250 –BKN 70 220/26/12/2910/018/ 8/007
51015 10028 20025 

10 A.M.
Weather: Overcast altostratus, few stratocumulus distant W, virga SE-SW
Temperature: 29F; Dew Point: 13F; Wind: W at 12 kts
Sea-level pressure: 30.23 ins. Hg, rising, then more slowly
Visibility: 80 miles
3-hr Precip: 0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 E110 OVC 80 238/29/13/2712/023/ FEW BINOVC DSNT W-NNW
FEW SC DSNT W VIRGA SE-SW/ 8/52/ 51018

1 P.M.
Weather: Overcast altostratus, breaks in overcast W-NNE
Temperature: 30F; Dew Point: 13F; Wind: WNW at 10kts
Sea-level pressure: 30.19 ins. Hg, falling, then more slowly
Visibility: 80 miles
6-hr Max temp: 30F
6-hr Min temp: 26F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E110 OVC 80 225/30/13/2910/019/ BINOVC W-NNE/ 8/02/
57013 10030 20026 


SUMMARY FOR SUNDAY, DECEMBER 15, 2019 

TEMPERATURE (DEGREES F)
MAX.....48   NORMAL.....39
MIN.....28   NORMAL.....24
MEAN....38   NORMAL.....32

DEPARTURE FROM 30-YEAR NORMAL..................... +6
TOTAL DEPARTURE FOR THE MONTH.....................-16 [-1.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............27  DEPARTURE....... -7
TOTAL HEATING UNITS FOR THE MONTH..............480  DEPARTURE.......+15
TOTAL HEATING UNITS FOR THE SEASON............1717  DEPARTURE.......-10
TOTAL HEATING UNITS LAST SEASON TO DATE.......1818  DEPARTURE......-101

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................53 W   AT 10:48 A.M.  
                   AERO.........................53 W   AT  4:00 P.M.   
                   ASOS.........................54 W   AT 10:49 A.M. 
                   DAVIS........................56 W   AT 10:46 A.M. RMY 50
FASTEST MILE FOR YESTERDAY......................43 W   AT 12:31 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................39 W   AT 12:31 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................42 W   AT 12:29 P.M.
AVERAGE WIND SPEED AND DIRECTION...............25.5 W                   
                   ASOS........................23.9 
                   DAVIS.......................25.7 W [274 deg.]

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..........5.27  DEPARTURE......+2.81
                         ASOS..............5.75
TOTAL PRECIPITATION FOR THE YEAR..........54.35  DEPARTURE......+3.35
                         ASOS.............55.15

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.......-0.5
TOTAL SNOWFALL FOR THE MONTH...............18.0  DEPARTURE......+12.6
TOTAL SNOWFALL FOR THE SEASON..............18.1  DEPARTURE......+10.1


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/-7/0.45/0.0/000/00            28 NNE AERO 29 N   RMY 31
11/19  42/36/39/-2/0.22/0.0/000/00            12 SSW AERO  9 NNW RMY N/A
11/20  38/33/36/-4/0.23/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/+2/0.13/0.0/000/00            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/+1/1.60/0.0/000/00            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/+8/0.24/0.0/011/02            30 W   AERO 32 W   RMY N/A TSTM
11/28  48/30/39/+1/0.07/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  36/23/30/-3/..../3.0/.../..            25 NW  AERO 25 NW  RMY N/A
12/12  29/17/23/-10/..../1.8/.../..           29 W   AERO 30 W   RMY 25
12/13  46/22/34/+2/..../0.0/.../..            25 SSE AERO 25 SSE RMY N/A
12/14  58/46/52/+20/..../0.0/.../..           45 S   AERO 41 S   RMY N/A
12/15  48/28/38/+6/0.00/0.0/.../..            53 W   AERO 53 W   RMY 50

12/16 The low since midnight is 25F, daily normal minimum is 24F 


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 16
HIGH 61 IN 1971
LOW -2 IN 1930
PRECIP 1.67 INS. IN 1960
SNOW 8.5 INS. IN 2007
WIND 73 MPH SSE IN 1982

RECORDS FOR DECEMBER 17
HIGH 63 IN 2000
LOW -10 IN 1942
PRECIP 3.03 INS. IN 1888
SNOWFALL 7.5 INS. IN 1988
PEAK GUST 78 MPH SSE IN 2000

TODAY'S REPORT PREPARED BY: Matt Douglas/Ann Murphy