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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, DECEMBER 27, 2017  
ALL TIMES ARE IN EASTERN STANDARD TIME

CLEAR, DRY, AND SUNNY DAY AFTER A BITTER 
COLD MORNING...

Temperatures have dropped a total of 18 degrees since 
yesterday's maximum temperature of 24F. This is 12 degrees 
below the daily normal of 36F. Since midnight today we have 
had a low of 6F. This is 14 chilly degrees below the daily 
normal of 20F. So far today we have had a high of 19F. This 
is 17 unseasonable degrees below the daily normal of 36F.
Yesterday had a peak gust from the west at 39 MPH. Winds 
continue to be from the west today but are lighter than 
yesterday with gusts over 20 kts (23 MPH) after 11:00 AM.
The sky remained clear with only a few stratocumulus and 
altocumulus during each observation. Even with low humidity 
and dew point visibility only reach a maximum of 70 miles 
by 1:00 PM today. 

Christmas day this year was in the top five for daily 
snowfall with a storm total of 3.2 inches. The last 
"white Christmas" was 5 years ago back in 2012. 

Blue Hill Observatory Largest Christmas Day Snowfalls, 
Inches (1885-2017)

1) 8.5 in 2002
2) 6.0 in 1902
3) 5.3 in 1974
4) 4.5 in 1961
5) 3.2 in 2017
6) 2.6 in 1966

1895-2016: 54 out of 122 years (44%) had 1 inch or more 
of snow on the ground on December 25th. 
2007:2016: 5 out of 10 years (50%) had 1 inch or more of 
snow on the ground on December 25th.   

Today's Observations:

7 A.M.
Weather: Clear, few distant stratocumulus ENE-ESE, 
few altocumulus ENE-ESE
Temperature: 8F; Dew Point: 0F; Wind: W at 12 kts
Sea-level pressure: 30.45 ins. Hg, steady then rising  
Visibility: 40 miles, distant fog in all directions 
6-hr Max temp: 12F
6-hr Min temp: 06F
24-hr precip: 0.00 ins.
24-hr snowfall: 0.0 ins. 
Snow depth: 3 ins.
BHO SA 1155 CLR 40 312/8/0/2712/045/ FEW SC DSNT ENE-ESE FEW 
AC E-SSW DSNT FG ALQDS/ 8/460 4/003 53009 10012 20006 

10 A.M.
Weather: Clear, few distant stratocumulus ENE-ESE
Temperature: 14F; Dew Point: 0F; Wind: WNW at 10G16 kts
Sea-level pressure: 30.46 ins. Hg, rising then falling
Visibility: 70 miles
3-hr precip: 0.00 ins. 
BHO SA 1455 CLR 70 315/14/0/2910G16/046/ FEW SC DSNT ENE-ESE 
FEW AC E-SSW/ 8/460 51003 

1 P.M.
Weather: Clear, few distant stratocumulus and cumulus WSW-E,
few altocumulus E-SSW
Temperature: 19F; Dew Point: -2F; Wind: WNW at 13G18 kts
Sea-level pressure: 30.39 ins. Hg, falling then more slowly 
Visibility: 70 miles 
6-hr Max temp: 19F
6-hr Min temp: 07F
6-hr precip: 0.00 ins.
Snow depth: 3 ins.
BHO SA 1755 CLR 70 290/19/M2/2913G18/039/ FEW SC/CU DSNT WSW-E 
FEW AC E-SSW/ 8/860 4/003 56025 10019 20007

SUMMARY FOR TUESDAY, DECEMBER 26, 2017

TEMPERATURE (DEGREES F)
MAX.....24   NORMAL.....36
MIN.....13   NORMAL.....20
MEAN....19   NORMAL.....28

DEPARTURE FROM 30-YEAR NORMAL...........................-9
TOTAL DEPARTURE FOR THE MONTH..........................-11 [-0.6 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............46  DEPARTURE..........+9
TOTAL HEATING UNITS FOR THE MONTH............865  DEPARTURE.........+10
TOTAL HEATING UNITS FOR THE SEASON..........1834  DEPARTURE........-283
TOTAL HEATING UNITS LAST SEASON TO DATE.....1886  DIFFERENCE........-52

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................39 W AT 10:43 A.M. 
                   AERO........................39 W AT 10:42 A.M.
                   ASOS........................N/A*
                   DAVIS.......................39 W AT 10:24 A.M. RMY 41
FASTEST MILE FOR YESTERDAY.....................30 W AT 10:43 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE..................N/A*
MAXIMUM 2-MINUTE DAVIS AVERAGE.................31 W AT 11:01 A.M.
AVERAGE WIND SPEED AND DIRECTION.............15.9 W   
                   ASOS......................N/A*  
                   DAVIS.....................15.4 W [374 DEG.]

*ASOS wind data likely erroneous due to ice

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..........2.95  DEPARTURE......-1.23
                         ASOS..............3.20
TOTAL PRECIPITATION FOR THE YEAR..........52.79  DEPARTURE......+0.08
                         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................8.9  DEPARTURE.......-1.8
TOTAL SNOWFALL FOR THE SEASON...............8.9  DEPARTURE.......-4.4

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 50/35/43/+6/0.04/0.0/262/47          28 NW  AERO 29 NW  RMY 30
12/02 42/29/36/0/0.00/0.0/033/06           20 NNW AERO 18 NNW RMY N/A
12/03 42/32/37/+1/0.00/0.0/172/31          14 N   AERO 10 N   RMY N/A 
12/04 43/32/38/+3/0.00/0.0/522/94          16 E   AERO 14 E   RMY N/A 
12/05 58/34/46/+11/0.18/0.0/000/00         62 S   AERO 66 S   RMY 65
12/06 56/32/44/+9/0.54/0.0/160/29          52 S   AERO 55 S   RMY N/A
12/07 44/30/37/+3/0.00/0.0/540/98          25 WSW AERO 24 WSW RMY 25
12/08 38/28/33/-1/0.00/0.0/116/21          21 W   AERO 18 W   RMY 20
12/09 34/28/31/-3./0.70/.../000/00         23 NNW AERO 23 NNW RMY 23 
12/10 35/27/31/-2/0.02/.../384/70          30 W   AERO 30 W   RMY 27 
12/11 38/29/34/+1/0.00/0.0/301/55          23 W   AERO 21 W   RMY 22
12/12 43/31/37/+4/0.06/0.0/000/00          35 W   AERO 31 W   RMY N/A
12/13 31/18/25/-7/0.00/0.0/312/57          44 W   AERO 44 W   RMY 44
12/14 27/14/21/-11/T/T/.../..              35 WSW AERO 33 W   RMY 34 
12/15 24/12/18/-14/T/.../.../..            25 W   AERO 23 W   RMY N/A
12/16 32/17/25/-6/0.00/0.0/.../..          33 W   AERO 35 W   RMY 36
12/17 27/14/21/-10/0.00/0.0/.../..         21 NW  AERO 21 NW  RMY 20
12/18 35/20/28/-3/T/.../.../..             20 SSE AERO 16 SSE RMY 20
12/19 49/34/42/+12/T/.../.../..            36 WNW AERO 35 SW  RMY 38  
12/20 42/26/34/+4/T/.../.../..             41 W   AERO 40 W   RMY 45 
12/21 32/23/28/-2/0.00/0.0/.../..          26 NW  AERO 24 NW  RMY 27
12/22 32/21/27/-2/..../.../.../..          18 E   AERO 17 E   RMY N/A
12/23 36/24/30/+1/..../.../.../..          31 WSW AERO 28 WSW RMY 31
12/24 35/29/32/+3/..../.../.../..          30 ENE AERO 25 ENE RMY N/A
12/25 35/21/28/0/..../.../.../..           50 W   AERO 54 W   RMY 47
12/26 24/13/19/-9/0.00/0.0/..../..         39 W   AERO 39 W   RMY 41     

12/27 Low temp since midnight is 6F; normal low is now 20F

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

RECORDS FOR DECEMBER 27
HIGH 57 IN 1895,1949
LOW -4 IN 1903
PRECIP 2.43 INS. IN 1969
SNOWFALL 11.2 INS. IN 1947
PEAK GUST 73 S IN 2011

RECORDS FOR DECEMBER 28
HIGH 60 IN 1982
LOW -2 IN 1933
PRECIP 2.16 INS. IN 1967
SNOWFALL 9.5 INS. IN 1967
PEAK GUST 89 MPH SSE IN 1983

TODAY'S REPORT PREPARED BY: Kaitlin Geagan