Sunday, December 3, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, DECEMBER 3, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

CLOUDS OFF AND ON THROUGHOUT THE DAY WITH SEASONABLE TEMPERATURES

Multiple layers of clouds started the day before giving way to
higher clouds.  Ground fog could be seen all around the
Observatory in patches this morning.  A dark smoke layer
moved in from the west and north, and was especially heavy near
Boston.   Temperatures fell back to near freezing overnight
and were slow to warm up this morning, but once the sun
climbed above the lower level clouds over the ocean temperatures
began climbing steadily and the humidity began to drop. Cirrus
clouds filled in during the afternoon with the sun dimly visible. The
visibility started poor with only 40 miles visible in all directions
and did not improve beyond 45 miles.

The mean temperature for the three Fall months, September
to November, was the warmest ever recorded at the Observatory.

PRELIMINARY STATS FOR NOVEMBER 2017

TEMPERATURE, Deg. F
Avg. Max. 49.8 [-0.2] Avg. Min. 32.9 [-0.6] Mean      41.4 [-0.3] 24-hour corrected mean: 41.7
Max. for month: 74F on 3rd
Min. for month: 18F on 11th

HEATING DEGREE DAYS
Total heating units: 701 [+3] Total for the season: 969 [-292] Total for last season: 1030

PRECIPITATION, Inches
Total: 2.04 [-2.72] Greatest in 24 hrs: 0.87 in. on the 22nd

WIND, mph
Avg. uncorrected wind speed: 12.7
Avg. corrected wind speed: 13.0
Prevailing wind direction: WNW at 12%
Peak gust and direction: 50 W on 19th

SUNSHINE:
Campbell-Stokes card minutes: 9,108 minutes of possible 17,010 or 54%
Astronomical total minutes: 9,431 minutes of possible 17,610 or 54%

BHO Warmest Fall (Sep-Nov) 24-hour Corrected Mean Temperature, deg F (1885-2017):

1) 55.3 in 2017
2) 55.1 in 2011
3) 54.8 in 1931
54.8 in 2015
5) 54.3 in 1946
54.3 in 2001

Today’s Observations:

7 A.M.
Weather: Scattered Cirrocumulus, few stratocumulus with a lower level of
stratocumulus offshore, patches of thin ground fog all quadrants, distant fog
all quadrants
Temperature: 34F; Dew Point: 26F; Wind: N at 7 kts
Sea-level pressure: 30.22 ins. Hg, steady then increasing
Visibility: 40 miles
6-hr Max temp: 36F
6-hr Min temp: 32F
24-hr precip: 0.00 ins.
BHO SA 1155 250 SCT 40 234/34/26/0407/022/ FEW SC ALQDS FEW LWR SC OFFSHR DSNT NE-SE
PTCHS THN GF ALQDS INVSN PRSNT ESTMTD TOP 4 HND OVR CTY W DSNT FG ALQDS/ 8/509
53002 10036 20032

10 A.M.
Weather: Broken Cirrostratus, few stratocumulus WSW, distant haze all quadrants
dark smoke layer along horizon W-ESE
Temperature: 38F; Dew Point: 26F; Wind: N at 5 kts (estimated)
Wind: Light and Variable
Sea-level pressure: 30.22 ins. Hg, rising, then falling
Visibility: 45 miles
3-hr precip: 0.00 ins.
BHO SA 1455 E250 BKN 45 243/38/26/VRB05/022/ FEW SC WSW
DRK K LYR ALG HRZN WND L/V/ 8/508 50009

1 P.M.
Weather: Overcast Cirrostratus, distant haze
Temperature: 41F; Dew Point: 27F; Wind: WNW at 4 kts (estimated)
Wind: Light
Sea-level pressure: 30.20 ins. Hg, decreasing then more slowly
Visibility: 45 miles
6-hr Max temp: 41F
6-hr Min temp: 34F
6-hr precip: 0.00 ins.
BHO SA 1755 E300 OVC 45 227/41/27/2904/020/ DSNT HAZE SUN DMLY VSBL
WND LGT/ 8/007 56016 10041 20034

SUMMARY FOR SATURDAY, DECEMBER 2, 2017

TEMPERATURE (DEGREES F)
MAX…..42   NORMAL…..44
MIN…..29   NORMAL…..28
MEAN….36   NORMAL…..36

DEPARTURE FROM 30-YEAR NORMAL………………………0
TOTAL DEPARTURE FOR THE MONTH………………………+6 [+2.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….29  DEPARTURE………..0
TOTAL HEATING UNITS FOR THE MONTH………….51  DEPARTURE……….-7
TOTAL HEATING UNITS FOR THE SEASON……….1020  DEPARTURE……..-299
TOTAL HEATING UNITS LAST SEASON TO DATE…..1072  DIFFERENCE……..-52

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….20 NNW  AT  1:13 A.M.
AERO……………………18 NNW  AT  1:13 A.M.
ASOS……………………19   N  AT  1:15 A.M.
DAVIS…………………..18 NNW  AT 12:41 A.M. RMY 14
FASTEST MILE FOR YESTERDAY…………………13 NNW  AT 1:17 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………14   N  AT 1:24 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..12   N  AT 1:16 A.M.
AVERAGE WIND SPEED AND DIRECTION………….6.4 NNW
ASOS………………….6.7
DAVIS…………………6.3 N [004 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……….0.04  DEPARTURE……-0.28
ASOS…………..0.04
TOTAL PRECIPITATION FOR THE YEAR……….49.88  DEPARTURE……+1.03
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…….-0.5
TOTAL SNOWFALL FOR THE SEASON……………0.0  DEPARTURE…….-3.1

PRELIMINARY CLIMATE SUMMARY FOR NOVEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/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

11/01 53/39/46/0/0.00/167/27           25 SE  AERO 24 SE  RMY 25
11/02 71/49/60/+14/0.00/000/00         28 SSE AERO 25 SSE RMY 27
11/03 74/47/61/+15/T/350/57            35 WNW AERO 35 WNW RMY 38
11/04 54/39/47/+2/0.00/545/89          31 NW  AERO 31 NW  RMY N/A
11/05 61/46/54/+9/0.01/006/01          26 S   AERO 24 S   RMY N/A
11/06 64/47/56/+11/0.05/000/00         32 S   AERO 28 SSW RMY 35
11/07 46/35/41/-4/0.11/145/24          26 NNW AERO 23 N   RMY 26
11/08 3/34/39/-5/0.08/295/49           26 N   AERO 23 N   RMY 27
11/09 50/31/41/-3/0.01/480/80          25 S   AERO 23 S   RMY N/A
11/10 45/20/33/-11/0.00/586/98         46 WNW AER0 44 WNW RMY 46
11/11 36/18/27/-16/0.00/589/99         28 WNW AERO 26 WNW RMY 28
11/12 44/27/36/-7/0.00/302/51          13 E   AERO  9 S   RMY 14
11/13 40/35/38/-5/0.26/000/00          20 NNW AERO 17 NNW RMY 20
11/14 40/33/37/-5/T/000/00             18 N   AERO 15 N   RMY 18
11/15 43/31/37/-5/0.00/417/71          20 NE  AERO 15 NE  RMY N/A
11/16 51/37/44/+2/0.21/012/02          32 SE  AERO 32 SE  RMY N/A TSTM
11/17 42/30/36/-5/0.00/565/97          41 WNW AERO 43 WNW RMY 47
11/18 49/26/38/-3/0.08/168/29          35 SSW AERO 35 SSW RMY 39
11/19 58/34/46/+5/0.36/231/40          50 W   AERO 50 W   RMY 54
11/20 39/31/35/-5/0.00/462/80          48 WNW AERO 50 WNW RMY 44
11/21 57/35/46/+6/0.00/506/88          46 SSW AERO 46 SSW RMY 48
11/22 53/35/44/+4/0.87/000/00          37 NW  AERO 38 NW  RMY 41
11/23 40/26/33/-6/0.00/571/100         26 NW  AERO 25 NW  RMY N/A
11/24 49/29/39/0/0.00/558/98           28 SSW AERO 26 SSW RMY 29
11/25 57/38/48/+9/0.00/523/92          29 SSW AERO 28 SSW RMY 31
11/26 46/33/40/+2/0.00/509/90          39 WNW AERO 41 WNW RMY 41
11/27 44/24/34/-4/0.00/254/45          37 W   AERO 39 W   RMY 36
11/28 45/19/32/-6/0.00/557/99          35 S   AERO 37 S   RMY N/A
11/29 58/34/46/+9/0.00/370/66          46 W   AERO 47 W   RMY 46
11/30 43/26/37/-2/0.00/263/47          25 SSE AERO 25 NNW RMY 25

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/+6/0.00/…/..          28 NW  AERO 29 NW  RMY 30
12/02 42/29/36/0/0.00/…/..           20 NNW AERO 18 NNW RMY 14

12/03 Low temp since midnight is 32F; normal low is now 28F

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

RECORDS FOR DECEMBER 3
HIGH 67 IN 2009
LOW  -1 IN 1890
PRECIP 2.10 INS. IN 1986
SNOWFALL 6.0 INS. IN 1963
PEAK GUST 73e MPH W IN 1942

RECORDS FOR DECEMBER 4
HIGH 67 IN 1998
LOW -4 IN 1940
PRECIP 1.87 INS. IN 1968
SNOWFALL 6.0 INS. IN 1907
PEAK GUST 73 MPH WNW IN 1980

TODAY’S REPORT PREPARED BY: Robert Millette