Saturday, December 16, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 16, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

0.1 IN. OF SNOW OVERNIGHT AND COLD TEMPERATURES

0.1 in. of snow fell last night on Great Blue Hill. This was
equal to a trace of liquid precipitation. The morning started
with mostly clear skies, but a layer of broken altocumulus moved
in by the afternoon. Distant haze remained in the area all day,
so visibility did not exceed 60 miles.

Yesterday, there was a maximum temperature of 24F and a minimum
of 12F, making the average for the day 18F (14F below normal).
Temperatures were slightly warmer today. The minimum this morning
was 17F, and a maximum of 31F was reached by the 1 P.M. EST
observation. The cumulative departure for the month of December
is now at +/- 0F.

Today’s Observations:

7 A.M.
Weather: Clear, few stratocumulus NNE-S, few altocumulus NNW-N, few
altocumulus NNW-N, few altostratus S-SE
Temperature: 17F; Dew Point: 14F; Wind: WSW at 8G14 kts
Sea-level pressure: 29.88 ins. Hg, rising, then less quickly
Visibility: 20 miles, hazy
6-hr Max temp: 20F
6-hr Min temp: 17F
24-hr precip: Trace
24-hr snowfall: 0.1 in.
Snow cover: 1 in.
BHO SA 1155 CLR 20 118/17/14/2508G14/988/ NEW SNW PST 24 HRS 0.1 INS FEW SC
NNE-S FEW AC NNW-N FEW AS S-SE HAZY/ 8/530 4/001 51023 10020 20017

10 A.M.
Weather: Clear, few cumulus NE, few altocumulus SW-WNW, few cirrus
in all directions
Temperature: 25F; Dew Point: 15F; Wind: W at 11G21 kts
Sea-level pressure: 29.94 ins. Hg, rising, then less quickly
Visibility: 60 miles, distant haze in all directions
3-hr precip: 0.00 ins.
3-hr snowfall: 0.0 ins.
BHO SA 1455 CLR 60 140/25/15/2611G21/994/ FEW CU NE FEW AC SW-WNW FEW CI
ALQDS DSNT HZ ALQDS/ 8/131 53022

1 P.M.
Weather: Few stratocumulus SE-NE, broken altocumulus
Temperature: 30F; Dew Point: 14F; Wind: WSW at 14G21 kts
Sea-level pressure: 29.89 ins. Hg, falling unsteadily
Visibility: 60 miles, distant haze in all directions
6-hr Max temp: 31F
6-hr Min temp: 17F
6-hr precip: 0.00 ins.
6-hr snowfall: 0.0 ins.
Snow cover: 1 in.
BHO SA 1755 E110 BKN 60 122/30/14/2514G21/989/ FEW SC SE-NE PK WND 2626/39
DSNT HZ ALQDS/ 8/330 4/001 56018 10031 20017

SUMMARY FOR FRIDAY, DECEMBER 15, 2017

TEMPERATURE (DEGREES F)
MAX…..24   NORMAL…..39
MIN…..12   NORMAL…..24
MEAN….18   NORMAL…..32

DEPARTURE FROM 30-YEAR NORMAL……………………..-14
TOTAL DEPARTURE FOR THE MONTH………………………+0 [-0.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….47  DEPARTURE………+13
TOTAL HEATING UNITS FOR THE MONTH…………464  DEPARTURE……….-1
TOTAL HEATING UNITS FOR THE SEASON……….1433  DEPARTURE……..-294
TOTAL HEATING UNITS LAST SEASON TO DATE…..1507  DIFFERENCE……..-74

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….25 W AT 12:17 A.M.
AERO……………………23 W AT 12:14 A.M.
ASOS……………………24 W AT 12:18 A.M.
DAVIS…………………..23 W AT 12:18 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY…………………19 W AT 12:23 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………18 W AT 12:23 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..18 W AT 12:23 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..6.4 S
ASOS…………………..6.4
DAVIS………………….6.4 WSW [247 DEG.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…TRACE  DEPARTURE……-0.16
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….1.54  DEPARTURE……-0.92
ASOS…………..1.63
TOTAL PRECIPITATION FOR THE YEAR……….51.38  DEPARTURE……+0.39
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……….0.1  DEPARTURE…….-0.4
TOTAL SNOWFALL FOR THE MONTH…………….5.7  DEPARTURE…….+0.4
TOTAL SNOWFALL FOR THE SEASON……………5.7  DEPARTURE…….-2.2

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 Low temp since midnight is 17F; 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 16
HIGH 61 IN 1971
LOW -2 IN 1930
PRECIP 1.67 INS. IN 1960
SNOW 8.5 INS. IN 2007
WIND 73 MPH SSE IN 1982

RECORDS FOR DECEMBER 17
HIGH 63 IN 2000
LOW -10 IN 1942
PRECIP 3.03 INS. IN 1888
SNOWFALL 7.5 INS. IN 1988
PEAK GUST 78 MPH SSE IN 2000

TODAY’S REPORT PREPARED BY: Lizzy Suzedell