Tuesday, December 11, 2018

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, DECEMBER 11, 2018
ALL TIMES ARE IN EASTERN STANDARD TIME

LIGHT WINDS AND FAIR WEATHER WITH PRESSURE
DECREASING THROUGHOUT THE DAY….

Afternoon cloud cover increased slightly with
a pressure drop of almost 5 millibars between
7 A.M. and 1 P.M. While skies were clear for
most of the day, scattered altocumulus developed
to the east and south of Blue Hill. Visibility
decreased from 70 miles to 40 miles since this
morning due to a thin smoke layer. Winds were
at or below 10 mph for the majority of the day,
with winds being calm at the 10 A.M. observation.
Wind speed picked back up a little following a
wind shift from north to southwest between 10 and
11 A.M. The highest wind observed so far today is
12 mph. The max temperature so far today is 35F,
5 degrees below the daily normal of 41F. The low
since midnight is 17F, 8 degrees below the daily
normal minimum of 25F.
BHO Wettest Novembers, inches (1886-2018):

1) 10.31 in 2018
2) 9.78 in 1983
3) 9.29 in 1945
4) 9.17 in 1972
5) 8.95 in 1895
6) 8.93 in 1988
7) 8.79 in 1963

BHO Wettest Falls (Sep-Nov), inches (1886-2018):

1) 25.41 in 2018
2) 23.18 in 2005
3) 23.13 in 1996
4) 22.47 in 1888
5) 20.65 in 2011
6) 20.64 in 1932
7) 20.08 in 1962
PRELIMINARY STATS FOR NOVEMBER 2018

TEMPERATURE, Deg. F
Avg. Max. 45.2 [-4.8] Avg. Min. 32.4 [-1.1] Mean 38.8 [-2.9] 24-hour corrected mean: 38.6
Max. for month: 65F on the 1st and 2nd
Min. for month: 9F on the 22nd and 23rd

HEATING DEGREE DAYS
Total heating units: 776 [+78] Total for the season: 1320 [+351] Total for last season: 969

PRECIPITATION, Inches
Total: 10.31 in. [+5.55] Greatest in 24 hrs: 1.78 ins. on 9th-10th

SNOWFALL, Inches
Total: 7.6 in. [+5.3] Greatest in 24 hrs: 7.5 ins. on 16th-17th

WIND, mph
Avg. uncorrected wind speed: 13.1
Avg. corrected wind speed: 13.4
Prevailing wind direction: WNW at 15%
Peak gust and direction: 59 W on the 3rd

SUNSHINE:
Campbell-Stokes card minutes: 6144 minutes of possible 17010 or 36%
Astronomical total minutes:   6359 minutes of possible 17623 or 36%

Today’s Observations:

7 A.M.
Weather: Clear, few distant cumulus
Temperature: 17F; Dew Point: 10F; Wind: N at 7 kts
Sea-level pressure: 30.20 ins. Hg, rising steadily
Visibility: 70 miles
6-hr Max temp: 23F
6-hr Min temp: 17F
24-hr Precip: 0.00 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 CLR 70 226/17/10/3607/020/ FEW DSNT
CU ALQDS/ 8/100 51006 10023 20017

10 A.M.
Weather: Clear, few cumulus in all directions
Temperature: 28F; Dew Point: 10F; Wind: Calm
Sea-level pressure: 30.16 ins. Hg, falling steadily
Visibility: 40 miles, thin smoke layer in all
directions
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 40 212/28/10/0000/016/ FEW CU THN
K LYR ALQDS WND CALM/ 8/100 58014

1 P.M.
Weather: Scattered altocumulus, few cumulus in all
directions
Temperature: 35F; Dew Point: 12F; Wind: SSW at 8 kts
Sea-level pressure: 30.06 ins. Hg, falling steadily
Visibility: 40 miles
6-hr Max temp: 35F
6-hr Min temp: 17F
6-hr Precip: 0.00 ins.
6-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1755 200 SCT 40 181/35/12/2008/006/ FEW CU
ALQDS/ 8/180 58031 10035 20017

SUMMARY FOR MONDAY, DECEMBER 10, 2018

TEMPERATURE (DEGREES F)
MAX…..36   NORMAL…..41
MIN…..22   NORMAL…..26
MEAN….29   NORMAL…..33

DEPARTURE FROM 30-YEAR NORMAL……………………-4
TOTAL DEPARTURE FOR THE MONTH…………………..-31 [-3.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..36   DEPARTURE………+4
TOTAL HEATING UNITS FOR THE MONTH………….332   DEPARTURE……..+31
TOTAL HEATING UNITS FOR THE SEASON………..1652   DEPARTURE……..+90
TOTAL HEATING UNITS LAST SEASON TO DATE……1243   DIFFERENCE……+409

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..24 NNW AT 9:18 A.M.
AERO…………………….23 NNW AT 9:18 A.M.
ASOS…………………….22 NNW AT 9:21 A.M.
DAVIS……………………23 NNW AT 9:20 A.M. RMY 22
FASTEST MILE FOR YESTERDAY………………….15 NW  AT 1:15 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….15 N   AT 9:39 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………16 NW  AT 1:15 A.M.
AVERAGE WIND SPEED AND DIRECTION……………9.6 NNW
ASOS……………………9.7
DAVIS………………….10.0 NNW [258 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……….1.04  DEPARTURE…….-0.61
ASOS…………..1.78
TOTAL PRECIPITATION FOR THE YEAR……….64.41  DEPARTURE……+14.42
ASOS………….67.41

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..-0.4
TOTAL SNOWFALL FOR THE MONTH…………….0.0  DEPARTURE……..-3.2
TOTAL SNOWFALL FOR THE SEASON……………7.6  DEPARTURE……..+1.8

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 65/49/57/+11/0.00/006/01         25 SSW AERO 24 SSW RMY N/A
11/02 65/52/59/+13/0.37/000/00         37 SSW AERO 41 SSW RMY N/A
11/03 64/42/53/+7/1.43/148/24          59 W   AERO 60 W   RMY 58
11/04 52/37/45/0/0.00/588/96           31 W   AERO 30 W   RMY N/A
11/05 49/40/45/0/0.34/000/00           30 ENE AERO 29 ENE RMY 28
11/06 58/45/52/+7/0.97/000/00          29 SSW AERO 29 SSW RMY 31
11/07 60/50/55/+10/0.00/593/98         30 WSW AERO 30 WSW RMY 32
11/08 52/37/45/+1/0.00/470/78          29 WNW AERO 26 WNW RMY 23
11/09 48/34/41/-3/1.23/240/40          43 E   AERO 40 E   RMY 42
11/10 45/32/39/-5/0.55/000/00          45 W   AERO 47 WNW RMY 46
11/11 43/30/37/-6/0.00/596/100         32 WNW AERO 30 W   RMY 32
11/12 48/27/38/-5/0.00/475/80          18 SW  AERO 18 SW  RMY N/A
11/13 52/37/45/+2/1.07/000/00          44 WNW AERO 44 WNW RMY 48
11/14 37/20/29/-13/0.00/471/80         45 WNW AERO 50 WNW RMY 50
11/15 30/19/25/-17/0.71/000/00         33 E   AERO 36 E   RMY N/A
11/16 41/30/36/-6/0.69/000/00          43 E   AERO 44 ENE RMY N/A
11/17 45/34/40/-1/0.00/111/19          28 W   AERO 27 W   RMY 28
11/18 40/30/35/-6/0.00/157/27          21 W   AERO 21 W   RMY M
11/19 38/33/36/-5/0.03/000/00          16 E   AERO 14 E   RMY N/A
11/20 38/31/35/-5/0.46/000/00          30 NE  AERO 30 NE  RMY N/A
11/21 39/20/30/-10/0.00/081/14         40 WNW AERO 46 WNW RMY 47
11/22 20/09/15/-25/0.00/567/99         36 NW  AERO 41 NW  RMY 42
11/23 30/09/20/-19/0.00/548/96         25 SW  AERO 25 SW  RMY 27
11/24 43/24/34/-5/0.00/302/53          27 SW  AERO 27 ESE RMY N/A
11/25 43/40/42/+3/0.94/000/00          39 ENE AERO 39 ENE RMY 39
11/26 44/39/42/+4/0.92/000/00          45 E   AERO 44 E   RMY 45
11/27 45/33/39/+1/0.60/141/25          44 ENE AERO 44 ENE RMY N/A
11/28 39/31/35/-3/0.00/180/32          37 WNW AERO 41 WNW RMY 42
11/29 43/30/37/0/0.00/315/56           40 NW  AERO 41 NW  RMY 44
11/30 39/27/33/-4/0.00/370/66          18 NW  AERO 16 NW  RMY N/A

DAILY RECORDS FOR NOVEMBER 2017

11/22/18: DAILY RECORD LOW MAXIMUM TEMPERATURE OF 20F,
BREAKS PREVIOUS RECORD OF 26F SET IN 1972 AND 2008
11/22/18: DAILY RECORD LOW MINIMUM TEMPERATURE OF 9F,
BREAKS PREVIOUS RECORD OF 12F SET IN 1987
11/23/18: DAILY RECORD LOW MINIMUM TEMPERATURE OF 9F,
TIES PREVIOUS RECORD OF 9F SET IN 1888

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 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

12/01 41/28/35/-2/0.00/391/70          20 NNW AERO 18 NNW RMY N/A
12/02 52/35/44/+8/1.04/000/00          28 ESE AERO 25 ESE RMY 27
12/03 54/38/46/+10/0.00/178/32         35 W   AERO 35 W   RMY 38
12/04 38/23/31/-4/0.00/516/93          30 WNW AERO 31 WNW RMY 33
12/05 33/18/26/-9/0.00/432/78          16 NNW AERO 15 NNW RMY N/A
12/06 37/24/31/-4/0.00/354/64          29 W   AERO 28 W   RMY 30
12/07 37/21/29/-5/0.00/…/..          29 NW  AERO 29 NW  RMY 32
12/08 27/15/21/-13/0.00/…/..         28 NW  AERO 27 NW  RMY 29
12/09 34/17/26/-8/0.00/…/..          23 SSW AERO 21 SSW RMY 22
12/10 36/22/29/-4/0.00/…/..          24 NNW AERO 23 NNW RMY 22

12/11 Low temp since midnight is 17F; normal low is 25F

DAILY EXTREMES
Temperature and precipitation records back to 1885, and

RECORDS FOR DECEMBER 11
HIGH 63 IN 1911
LOW -1 IN 1988
PRECIP 2.36 INS. IN 1992
SNOWFALL 6.0 INS. IN 1894
PEAK GUST 78 S IN 1969

RECORDS FOR DECEMBER 12
HIGH 67 IN 1979
LOW -3 IN 1988
PRECIP 3.94 INS. IN 1992
SNOWFALL 20.3 INS. IN 1960
PEAK GUST 75 MPH SSE IN 2008

TODAY’S REPORT PREPARED BY: Benjamin Turner