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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, DECEMBER 14, 2017  
ALL TIMES ARE IN EASTERN STANDARD TIME
 
SKY CLEARS AFTER MORNING FLURRIES...

This morning began with light snow flurries 
which only left a dusting of snow on top of 
Great Blue Hill. Temperatures continue to be 
below seasonable today with a high of 27F by
1:00 P.M. This is 13 degrees below the normal 
of 40F. We observed yesterday's max temperature 
of 31F at midnight. The daytime high was 22F, 
18 degrees below the daily normal. Wind from 
the WNW was light in the morning but has begun 
picking up this afternoon with a peak gust of 
26 kts (30 MPH). Visibility greatly increased 
throughout the day from 15 miles at 7:00 AM 
to 80 miles by 10:00 AM. 

Today's Observations:

7 A.M.
Weather: Light snow, overcast nimbostratus 
Temperature: 18F; Dew Point: 13F; Wind: W at 5 kts,
Wind: Light 
Sea-level pressure: 29.61 ins. Hg, rising unsteadily     
Visibility: 15 miles, distant fog in all directions  
6-hr Max temp: 19F
6-hr Min temp: 18F
24-hr precip: Trace
24-hr snowfall: Trace 
Snow cover: 1 in.  
BHO SA 1155 E50 OVC 15S- 026/18/13/2705/961/ NEW SNW 
PST 24 HRS TRACE DSNT FG ALQDS WND LGT/ 8/6// 4/001 
52007 10019 20018  

10 A.M.
Weather: Broken Altostratus, few cumulus distant along 
horizon NNE-SSE, Sun dimly visible 
Temperature: 21F; Dew Point: 14F; Wind: NW at 5 kts,
Wind: Light
Sea-level pressure: 29.63 ins. Hg, falling then rising 
Visibility: 80 miles
3-hr precip: Trace 
3-hr snowfall: Trace 
BHO SA 1455 E200 BKN 80 034/21/14/3105/963/ FEW CU ALG HRZN 
DSNT NNE-SSE SUN DMLY VSBL NEW SNW PST 3 HRS TRACE WND LGT/ 
8/110 MANUAL 600// 53008 

1 P.M.
Weather: Few cumulus in all directions, few cirrostratus
along horizon ENE-SE 
Temperature: 26F; Dew Point: 12F; Wind: W at 15G26 kts,
Peak Wind: 26 kts (30 MPH) at 12:59 P.M. EST 
Sea-level pressure: 29.65 ins. Hg, rising then falling  
Visibility: 80 miles  
6-hr Max temp: 27F
6-hr Min temp: 18F
6-hr precip: Trace
6-hr snowfall: Trace
Snow cover: 1 in. 
BHO SA 1755 CLR 80 039/26/12/3015G26/965/ FEW CU ALQDS FEW CS 
ALG HRZN ENE-SE NEW SNW PST 6 HRS TRACE PK WND 3026/59/ 8/105 
4/001 53005 10027 20018  
  
SUMMARY FOR WEDNESDAY, DECEMBER 13, 2017
 
TEMPERATURE (DEGREES F)
MAX.....31   NORMAL.....40
MIN.....18   NORMAL.....25
MEAN....25   NORMAL.....32

DEPARTURE FROM 30-YEAR NORMAL...........................-7
TOTAL DEPARTURE FOR THE MONTH..........................+25 [+1.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............40  DEPARTURE..........+7
TOTAL HEATING UNITS FOR THE MONTH............373  DEPARTURE.........-25
TOTAL HEATING UNITS FOR THE SEASON..........1342  DEPARTURE........-318
TOTAL HEATING UNITS LAST SEASON TO DATE.....1431  DIFFERENCE........-89

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................44 W AT 10:53 A.M. 
                   AERO........................44 W AT 10:52 A.M.
                   ASOS........................44 W AT 12:13 P.M.
                   DAVIS.......................44 W AT 11:37 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY.....................32 W AT 10:27 A.M.    
MAXIMUM 2-MINUTE ASOS AVERAGE..................32 W AT 10:28 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE.................32 W AT 12:17 P.M.
AVERAGE WIND SPEED AND DIRECTION.............21.2 W 
                   ASOS......................21.2
                   DAVIS.....................20.6 W [281 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..........1.54  DEPARTURE......-0.60
                         ASOS..............1.63
TOTAL PRECIPITATION FOR THE YEAR..........51.38  DEPARTURE......+0.71
                         ASOS...............N/A **
** ASOS annual total not available due to erroneous readings

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.......-0.5
TOTAL SNOWFALL FOR THE MONTH................5.6  DEPARTURE.......+1.1
TOTAL SNOWFALL FOR THE SEASON...............5.6  DEPARTURE.......-1.5 

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 50/35/43/+6/0.04/262/47          28 NW  AERO 29 NW  RMY 30
12/02 42/29/36/0/0.00/033/06           20 NNW AERO 18 NNW RMY N/A
12/03 42/32/37/+1/0.00/172/31          14 N   AERO 10 N   RMY N/A 
12/04 43/32/38/+3/0.00/522/94          16 E   AERO 14 E   RMY N/A 
12/05 58/34/46/+11/0.18/000/00         62 S   AERO 66 S   RMY 65
12/06 56/32/44/+9/0.54/160/29          52 S   AERO 55 S   RMY N/A
12/07 44/30/37/+3/0.00/522/98          25 WSW AERO 24 WSW RMY 25
12/08 38/28/33/-1/0.00/.../..          21 W   AERO 18 W   RMY 20
12/09 34/28/31/-3./..../.../..         23 NNW AERO 23 NNW RMY 23 
12/10 35/27/31/-2/..../.../..          30 W   AERO 30 W   RMY 27 
12/11 38/29/34/+1/0.00/.../..          23 W   AERO 21 W   RMY 22
12/12 43/31/37/+4/0.06/.../..          35 W   AERO 31 W   RMY N/A
12/13 31/18/25/-7/0.00/.../..          44 W   AERO 44 W   RMY 44

12/14 Low temp since midnight is 18F; normal low is now 24F

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

RECORDS FOR DECEMBER 14
HIGH 62 IN 1901
LOW -6 IN 1893
PRECIP 1.94 INS. IN 2002
SNOWFALL 8.0 INS. IN 1907
PEAK GUST 78e ENE IN 1941

RECORDS FOR DECEMBER 15
HIGH 64 IN 1975
LOW 4 IN 1900, 1905, 1933
PRECIP 1.80 INS. IN 1981
SNOW 7.5 INS. IN 1951
PEAK GUST 65 MPH NW IN 1991

TODAY'S REPORT PREPARED BY: Kaitlin Geagan