Sunday, December 31, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, DECEMBER 31, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

BELOW NORMAL TEMPERATURES CONTINUE AFTER A LIGHT SNOWFALL

Light snow began to fall at Great Blue Hill yesterday and ended with
half an inch of new snow on the ground.  The current snow depth is at
3 ins.

A minimum of 4F was measured this morning shortly before 7:00 A.M. EST
with temperatures slowly warming throughout the morning. Yesterday, a
high of 14F was reached in the  afternoon. with temperatures 19 degrees
below normal.

Winds picked up this morning, gusting into the 30s out of the WNW.
This created wind chills at the summit of -19 degrees.

Today’s Observations:

7 A.M.
Weather: Clear, Few stratocumulus and cumulus along the horizon NNE-S
Temperature: 4F; Dew Point: -1F; Wind: W at 8 kts
Sea-level pressure: 30.07 ins. Hg, rising, then more slowly
Visibility: 40 miles, light distant haze
6-hr Max temp: 8F
6-hr Min temp: 3F
24-hr precip: 0.03 ins.
24-hr snowfall: 0.5 ins.
Snow depth: 3 ins.
BHO SA 1155 CLR 40 182/4/M1/3008/007/ NEW SNW PST 24 HRS 0.5 INS FEW CU/SC
DSNT ALG HRZN NNE-S LGT DSNT HZ/ 8/400 4/003 51025 MANUAL 70003 ASOS 70003
10008 20003

10 A.M.
Weather: Few thin cirrus, few cumulus distant along the horizon offshore
Temperature: 7F; Dew Point: -5F; Wind: W at 16 kts
Peak Gust: 28 MPH, W
Sea-level pressure: 30.10 ins. Hg, rising, then more quickly
Visibility: 50 miles, light distant haze
3-hr precip: 0.00 ins.
BHO SA 1455 CLR 50 192/7/M5/3016G25/010/ FEW THN CI FEW CU DSNT ALG HRZN
OFFSHR LGT DSNT HZ PK WND 3028/23/ WND CHILL -15F/ 8/102 53012

1 P.M.
Weather: Broken cirrostratus, few cumulus distant along the horizon offshore
Temperature: 10F; Dew Point: -6F; Wind: W at 17 kts,
Peak Gust: 28 MPH, W
Sea-level pressure: 30.05 ins. Hg, falling, then more slowly
Visibility: 50 miles, light distant haze
6-hr Max temp: 10F
6-hr Min temp: 4F
6-hr precip: 0.00
6-hr snowfall: 0.0
Snow depth: 3 ins.
BHO SA 1755 E250 BKN 50 178/10/M6/2917/005/ FEW CU DSNT ALG HRZN OFFSHR
LGT DSNT HZ PK WND 2828/09/ 8/106 4/003 56014 10010 20004

SUMMARY FOR SATURDAY, DECEMBER 30, 2017

TEMPERATURE (DEGREES F)
MAX…..14   NORMAL…..35
MIN……1   NORMAL…..20
MEAN…..8   NORMAL…..27

DEPARTURE FROM 30-YEAR NORMAL……………………..-19
TOTAL DEPARTURE FOR THE MONTH……………………..-78 [-2.6 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….57  DEPARTURE………+19
TOTAL HEATING UNITS FOR THE MONTH………..1093  DEPARTURE………+88
TOTAL HEATING UNITS FOR THE SEASON……….2062  DEPARTURE……..-205
TOTAL HEATING UNITS LAST SEASON TO DATE…..1999  DIFFERENCE……..+63

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….21 W   AT 12:34 A.M.
AERO……………………18 W   AT 12:50 A.M.*
ASOS……………………21 WNW AT  1:00 A.M.
DAVIS…………………..19 WNW AT 12:34 A.M. RMY 24
FASTEST MILE FOR YESTERDAY…………………15 W   AT 4:25 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………15 WNW AT 4:28 A.M
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..14 WNW AT 1:09 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..7.3 W
ASOS…………………..7.9
DAVIS………………….7.3 W [279 DEG.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.03  DEPARTURE……-0.11
ASOS…………..0.03
TOTAL PRECIPITATION FOR THE MONTH……….2.98  DEPARTURE……-1.77
ASOS…………..3.23
TOTAL PRECIPITATION FOR THE YEAR……….52.82  DEPARTURE……-0.46
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……….0.5  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE MONTH…………….9.4  DEPARTURE…….-3.4
TOTAL SNOWFALL FOR THE SEASON……………9.4  DEPARTURE…….-6.0

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 10/1/6/-22/0.00/0.0/…./..          37 WNW AERO 44 WNW RMY 43
12/29 13/-3/5/-22/0.00/0.0/…/..          25 W   AERO 25 W   RMY 27
12/30 14/1/8/-19/0.03/0.5/…/..           21 W   AERO 18 W   RMY 24

12/31 Low temp since midnight is 4F; normal low is now 19F

DAILY RECORDS FOR DECEMBER 2017

12/28/17: DAILY RECORD LOW MAXIMUM TEMPERATURE OF 10F,
PREVIOUS RECORD OF 18 SET IN 1894

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

RECORDS FOR DECEMBER 31
HIGH 62 IN 1965
LOW -12 IN 1917
PRECIP 0.96 INS. IN 1906
SNOWFALL 7.5 INS. IN 2008
PEAK GUST 78 MPH NW IN 1990

RECORDS FOR JANUARY 1
HIGH 58F IN 1966
LOW -6F IN 1918
PRECIP 1.45 INS. IN 1982
SNOWFALL 7.2 INS. IN 1938
PEAK GUST 90e MPH S IN 1945

TODAY’S REPORT PREPARED BY: Robert Millette