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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 29, 2017  
ALL TIMES ARE IN EASTERN STANDARD TIME

OVERNIGHT TEMPERATURES COLDEST SO FAR THIS YEAR...

Temperatures have been well below seasonable again
today and yesterday. Yesterday we had a maximum temp 
of 10F. This is 26 chilly degrees below the normal 
daily max of 36F. Overnight temperatures dipped down
to a bitter -3F degrees, which is 23 degrees below the 
normal daily minimum temp of 20F. This is the coldest
temperature so far this year. So far today we have had 
a high again of 10F. This is 25 degrees below the normal 
of 35F.
Winds continue to be from the W/WNW but decreased today
since yesterday's peak gust of 32 kts (37 MPH). Although
temperatures were colder than yesterday the air felt 
milder without a wind chill. A distant haze kept 
visibility down to 40 miles for most of the day.   

FROM THE RECORD BOOKS...
100 years ago today was the first day of a seven-day period of 
extreme cold in New England that lasted from December 29, 1917 
to January 4, 1918. This week featured high temperatures of 16F 
or colder on each day including a maximum of only -3F on December 
30th, 1917, which is the coldest high temperature for any calendar 
day ever recorded at the Observatory. Low temperatures were below 
0F on six of the seven days including a minimum of -17F on the 
30th.  Below are the high, low, and mean temperatures (deg F) 
for each of those seven days at Blue Hill:

12/29/1917: 16/-10/3
12/30/1917: -3/-17/-10
12/31/1917: 5/-12/-3
1/1/1918: 6/-6/0
1/2/1918: 7/-7/0
1/3/1918: 9/1/5
1/4/1918: 15/-2/7

Today's Observations:

7 A.M.
Weather: Broken altocumulus, broken cirrostratus, few
stratocumulus NNE-E
Temperature: 0F; Dew Point: -8F; Wind: WNW at 6 kts
Wind: Light
Sea-level pressure: 30.27 ins. Hg, falling, then more slowly 
Visibility: 40 miles, distant haze 
6-hr Max temp: 0F
6-hr Min temp: -3F
24-hr precip: 0.00 ins.
24-hr snowfall: 0.0 ins. 
Snow depth: 2 ins.
BHO SA 1155 E120 BKN 250 BKN 40 251/0/M8/2906/027/ FEW SC DSNT 
ALG HRZN NNE-E WND LGT DSNT HZ/ 8/436 4/002 56010 10000 21003 

10 A.M.
Weather: Broken altocumulus, broken altostratus, few 
stratocumulus and cumulus along the horizon ENE-E, sun 
dimly visible 
Temperature: 3F; Dew Point: -8F; Wind: W at 03 kts,
Wind: Light
Sea-level pressure: 30.24 ins. Hg, steady then falling
Visibility: 50 miles, distant haze
3-hr precip: 0.00 ins. 
BHO SA 1455 E70 BKN 200 BKN 50 243/3/M8/2803/024/ FEW SC/CU DSNT 
ALG HRZN ENE-E SUN DMLY VSBL DSNT HZ WND LGT / 8/670 56008  

1 P.M.
Weather: Broken altocumulus, broken altostratus, few 
stratocumulus and cumulus along the horizon NNE-ENE 
Temperature: 10F; Dew Point: -8F; Wind: WSW at 7 kts
Sea-level pressure: 30.15 ins. Hg, falling, then more slowly 
Visibility: 40 miles, distant haze 
6-hr Max temp: 10F
6-hr Min temp: -1F
6-hr precip: 0.00 ins.
Snow depth: 2 ins.
BHO SA 1755 E90 BKN E200 OVC 40 210/10/M8/2507/015/ FEW SC/CU DSNT 
ALG HRZN NNE-ENE BINOVC WSW-WNW DSNT HZ/ 8/870 4/002 56033 
10010 21001 

SUMMARY FOR THURSDAY, DECEMBER 28, 2017

TEMPERATURE (DEGREES F)
MAX.....10   NORMAL.....36
MIN......1   NORMAL.....20
MEAN.....6   NORMAL.....28

DEPARTURE FROM 30-YEAR NORMAL..........................-22 
TOTAL DEPARTURE FOR THE MONTH..........................-37 [-1.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............59  DEPARTURE.........+22
TOTAL HEATING UNITS FOR THE MONTH............976  DEPARTURE.........+46
TOTAL HEATING UNITS FOR THE SEASON..........1945  DEPARTURE........-246
TOTAL HEATING UNITS LAST SEASON TO DATE.....1935  DIFFERENCE........+10

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................37 WNW AT 12:03 P.M. 
                   AERO........................44 WNW AT  2:39 P.M.
                   ASOS........................39 WNW AT 11:59 P.M. 
                   DAVIS.......................41 WNW AT 12:02 P.M. RMY 43
FASTEST MILE FOR YESTERDAY.....................30 WNW AT  2:41 P.M.* 
MAXIMUM 2-MINUTE ASOS AVERAGE..................26 W   AT 12:00 A.M
MAXIMUM 2-MINUTE DAVIS AVERAGE.................31 NW  AT  2:41 P.M.
AVERAGE WIND SPEED AND DIRECTION.............16.3 WNW   
                   ASOS.........................M  
                   DAVIS.....................15.5 WNW [300 DEG.]
*Last of multiple fastest miles

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.15
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.95  DEPARTURE......-1.52
                         ASOS..............3.20
TOTAL PRECIPITATION FOR THE YEAR..........52.79  DEPARTURE......-0.21
                         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.......-0.6
TOTAL SNOWFALL FOR THE MONTH................8.9  DEPARTURE.......-2.9
TOTAL SNOWFALL FOR THE SEASON...............8.9  DEPARTURE.......-5.5

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/+6/0.04/0.0/262/47         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/-7/0.00/0.0/372/68         44 W   AERO 44 W   RMY 44
12/14 27/14/21/-11/T/T/257/47             35 WSW AERO 33 W   RMY 34 
12/15 24/12/18/-14/T/.../011/02           25 W   AERO 23 W   RMY N/A
12/16 32/17/25/-6/0.00/0.0/382/70         33 W   AERO 35 W   RMY 36
12/17 27/14/21/-10/0.00/0.0/425/78        21 NW  AERO 21 NW  RMY 20
12/18 35/20/28/-3/T/.../011/02            20 SSE AERO 16 SSE RMY 20
12/19 49/34/42/+12/T/.../185/34           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 19/6/13/-15/0.00/0.0/..../..        28 WNW AERO 25 WNW RMY N/A
12/28 10/1/-22/0.00/0.0/..../..           37 WNW AERO 44 WNW RMY 43    

12/29 Low temp since midnight is -3F; 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 29
HIGH 72 IN 1984
LOW -19 IN 1933 (RECORD FOR DECEMBER)
PRECIP 1.91 INS. IN 1945
SNOWFALL 18.4 INS. IN 1945
PEAK GUST 95 MPH S IN 1966 (RECORD FOR DECEMBER)

RECORDS FOR DECEMBER 30
HIGH 60 IN 1984
LOW -18 IN 1933
PRECIP 1.48 INS. IN 1891
SNOWFALL 7.5 INS. IN 1956
PEAK GUST 81 MPH WNW IN 1962

TODAY'S REPORT PREPARED BY: Kaitlin Geagan