Monday, December 18, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, DECEMBER 18, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

OVERCAST SKIES AND DECREASED VISIBILITY

A layer of overcast stratus stayed in the area all day. A layer
of smoke was observed in the morning along the western horizon.
Visibility in the morning was around 50 miles, but it decreased
to 20 miles in the early afternoon because of distant fog. Light
snow fell in the late morning, but only a trace fell. Winds were
very light out of the SE this morning, with a shift to the S this
afternoon. Temperatures got down to a minimum of 20F this morning,
and a maximum temperature of 31F was reached by the 1:00 P.M. EST
observation. The average temperature yesterday was 10F below normal,
with a minimum of 14F and a maximum of only 27F. Today will likely
be the 6th day in a row with below normal temperatures.

Today’s Observations:

7 A.M.
Weather: Overcast stratus, layer of smoke along horizon SE-NE
Temperature: 23F; Dew Point: 12F; Wind: SE at 3 kts,
Wind Speed: Light
Sea-level pressure: 30.18 ins. Hg, falling, then rising
Visibility: 50 miles
6-hr Max temp: 23F
6-hr Min temp: 20F
24-hr precip: 0.00 ins.
24-hr snowfall: 0.0 ins.
Snow cover: 1 in.
BHO SA 1155 E023 OVC 50 221/23/12/1403/018/ K LYR ALG HRZN SE-NE WND LGT/
8/6// 55009 10023 20020

10 A.M.
Weather: Light snow, overcast stratus. thin layer of smoke along horizon
SW-NE
Temperature: 26F; Dew Point: 10F; Wind: SE at 5 kts,
Wind Speed: Light
Sea-level pressure: 30.14 ins. Hg, falling unsteadily
Visibility: 50 miles
3-hr precip: Trace
3-hr snowfall: Trace
BHO SA 1455 E017 OVC 50S- 207/26/10/1405/014/ NEW SNW PST 3 HRS TRACE THN K
LYR ALG HRZN SW-NE WND LGT/ 8/6// MANUAL 600// 58014

1 P.M.
Weather: Overcast stratus
Temperature: 30F; Dew Point: 20F; Wind: S at 5 kts,
Wind Speed: Light
Sea-level pressure: 30.05 ins. Hg, falling, then less quickly
Visibility: 20 miles, distant fog in all directions
6-hr Max temp: 31F
6-hr Min temp: 23F
6-hr precip: Trace
6-hr snowfall: Trace
Snow cover: 1 in.
BHO SA 1755 E018 OVC 20 176/30/20/1805/005/ NEW SNW PST 6 HRS TRACE DSNT FG
ALQDS WND LGT/ 8/6// 4/001 MANUAL 600// 56031 10031 20023

SUMMARY FOR SUNDAY, DECEMBER 17, 2017

TEMPERATURE (DEGREES F)
MAX…..27   NORMAL…..39
MIN…..14   NORMAL…..23
MEAN….21   NORMAL…..31

DEPARTURE FROM 30-YEAR NORMAL……………………..-10
TOTAL DEPARTURE FOR THE MONTH……………………..-16 [-1.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….44  DEPARTURE………+10
TOTAL HEATING UNITS FOR THE MONTH…………548  DEPARTURE………+15
TOTAL HEATING UNITS FOR THE SEASON……….1517  DEPARTURE……..-278
TOTAL HEATING UNITS LAST SEASON TO DATE…..1600  DIFFERENCE……..-83

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….21 NW  AT 11:33 A.M.
AERO……………………21 NW  AT  9:44 A.M.
ASOS……………………20 NW  AT 11:35 A.M.
DAVIS…………………..19 NW  AT 10:11 A.M. RMY 20
FASTEST MILE FOR YESTERDAY…………………15 NW  AT  9:50 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………15 NW  AT 11:36 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..15 NW  AT  9:49 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..8.6 WNW
ASOS…………………..8.6
DAVIS………………….8.4 NW [312 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……-1.23
ASOS…………..1.63
TOTAL PRECIPITATION FOR THE YEAR……….51.38  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…….-0.4
TOTAL SNOWFALL FOR THE MONTH…………….5.7  DEPARTURE…….-0.6
TOTAL SNOWFALL FOR THE SEASON……………5.7  DEPARTURE…….-3.2

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 27/14/21/-11/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/…/..          33 W   AERO 35 W   RMY 36
12/17 27/14/-10/0.00/…/..            21 NW  AERO 21 NW  RMY 20

12/18 Low temp since midnight is 20F; normal low is now 23F

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

RECORDS FOR DECEMBER 18
HIGH 59 IN 1928
LOW -11 IN 1919
PRECIP 1.44 INS. IN 1915
SNOWFALL 7.0 INS. IN 1904
PEAK GUST 76e W IN 1978

RECORDS FOR DECEMBER 19
HIGH 59 IN 1899
LOW -1 IN 1919
PRECIP 2.06 INS. IN 1986
SNOWFALL 14.1 INS. IN 1945
PEAK GUST 68 NE IN 1986

TODAY’S REPORT PREPARED BY: Lizzy Suzedell