Saturday, December 9, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 9, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

FIRST SNOWFALL OF THE SEASON ARRIVES TODAY…

The sky was overcast with lowering altostratus at
sunrise today, with just a few breaks visible in the
distance to the NNW-N and a few higher clouds visible
in the distance to the SSE-S. The visibility was still
70 miles at 7 AM, though this began to drop soon after.
Light snow began at 8:10 AM and continued very light
for the next few hours. Only a trace of snowfall was
measured for the three hours ending at 10 AM, when the
visibility had dropped to just five miles. The snow
began to pick up in intensity around 11 AM and began
accumulating before Noon. As of 1 PM a total of 0.8 inches
of new snow and a liquid equivalent precipitation of
0.10 inches were measured with moderate snow in progress.

Today’s Observations:

7 A.M.
Weather: Overcast altostratus, few breaks in overcast distant
NNW-N, few higher clouds visible distant SSE-S, light wind
Temperature: 33F; Dew Point: 16F; Wind: W at 1 kts (estimated)
Wind: Light
Sea-level pressure: 29.96 ins. Hg, falling unsteadily
Visibility: 70 miles
6-hr Max temp: 33F
6-hr Min temp: 32F
24-hr precip: 0.00 ins.
24-hr snowfall: 0.0 ins.
BHO SA 1155 E80 OVC 70 144/33/16/E2701/996/ FEW BINOVC DSNT
NNW-N FEW HIR CLDS VSBL DSNT SSE-S/ 8/02/ 57002 10033 20032

10 A.M.
Weather: Light snow, overcast nimbostratus, light wind
Temperature: 31F; Dew Point: 26F; Wind: NNW at 5 kts,
Wind: Light
Sea-level pressure: 29.95 ins. Hg, increasing, the decreasing
Visibility: 5 miles
3-hr precip: 0.00 ins.
3-hr snowfall: Trace
BHO SA 1455 E50 OVC 5S- 143/31/26/3405/995/ WND LGT/ 8/02/ 58001

1 P.M.
Weather: Moderate snow and fog, scattered stratus fractus,
overcast nimbostratus
Temperature: 30F; Dew Point: 29F; Wind: N at 4 kts,
Wind: Light
Sea-level pressure: 29.88 ins. Hg, falling, then more slowly
Visibility: 1/2 miles
6-hr Max temp: 34F
6-hr Min temp: 30F
6-hr precip: 0.10 ins.
6-hr snowfall: 0.8 ins.
BHO SA 1755 3 SCT E7 OVC 1/2SF 120/30/29/1004/988/
TOTAL NEW SNW PST 6 HRS 0.8 INS WND LGT/ 8/72/ 4/001 56023 6010/
10034 20030
SUMMARY FOR FRIDAY, DECEMBER 8, 2017

TEMPERATURE (DEGREES F)
MAX…..38   NORMAL…..42
MIN…..28   NORMAL…..26
MEAN….33   NORMAL…..34

DEPARTURE FROM 30-YEAR NORMAL………………………-1
TOTAL DEPARTURE FOR THE MONTH……………………..+32 [+3.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….32  DEPARTURE……….+1
TOTAL HEATING UNITS FOR THE MONTH…………206  DEPARTURE………-32
TOTAL HEATING UNITS FOR THE SEASON……….1175  DEPARTURE……..-325
TOTAL HEATING UNITS LAST SEASON TO DATE…..1251  DIFFERENCE……..-76

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….21 W   AT 10:52 A.M.
AERO……………………18 W   AT 10:50 A.M.
ASOS……………………20 WNW AT 10:52 A.M.
DAVIS…………………..19 W   AT 10:52 A.M. RMY 20
FASTEST MILE FOR YESTERDAY…………………14 W   AT 10:52 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………15 W   AT 10:54 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..16 W   AT 10:53 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..8.1 WSW
ASOS…………………..8.5
DAVIS………………….7.9 WSW  [254 DEG.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.17
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….0.76  DEPARTURE……-0.56
ASOS…………..0.83
TOTAL PRECIPITATION FOR THE YEAR……….50.60  DEPARTURE……+0.75
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…….-0.3
TOTAL SNOWFALL FOR THE MONTH…………….0.0  DEPARTURE…….-2.4
TOTAL SNOWFALL FOR THE SEASON……………0.0  DEPARTURE…….-5.0

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/…/..          28 NW  AERO 29 NW  RMY 30
12/02 42/29/36/0/0.00/…/..           20 NNW AERO 18 NNW RMY N/A
12/03 42/32/37/+1/0.00/…/..          14 N   AERO 10 N   RMY N/A
12/04 43/32/38/+3/0.00/…/..          16 E   AERO 14 E   RMY N/A
12/05 58/34/46/+11/…/…/..          62 S   AERO 66 S   RMY 65
12/06 56/32/44/+9/…/…/..           52 S   AERO 55 S   RMY N/A
12/07 44/30/37/+3/0.00/…/..          25 WSW AERO 24 WSW RMY 25
12/08 38/28/33/-1/0.00/…/..          21 W   AERO 18 W   RMY 20

12/09 Low temp since midnight is 32F; normal low is now 26F

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

RECORDS FOR DECEMBER 9
HIGH 68 IN 1966
LOW -14 IN 1902
PRECIP 3.23 INS. IN 2014
SNOWFALL 10.8 INS. IN 2005
PEAK GUST 66 SE IN 1973

RECORDS FOR DECEMBER 10
HIGH 62 IN 1946
LOW -6 IN 1902
PRECIP 1.67 INS. IN 1907
SNOWFALL 6.0 INS. IN 1905
PEAK GUST 66e SW IN 1940

TODAY’S REPORT PREPARED BY: Afshin Pourmokhtarian/Michael Iacono