Sunday, December 15, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, DECEMBER 15, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

VERY WINDY OUT OF THE WEST WITH MOSTLY
CLOUDY SKIES….

Today was very windy, with a max gust so far of
53 mph from the west. The wind speed was at or above
25 mph, with frequent gusts above 40 mph. The wind
is due to the rapid increase in pressure; almost 12
millibars since this morning. With the high pressure
moving in and the low pressure moving out, skies have
become gradually less cloudy as the day went on.

Visibility was 70 miles on average, being only 30 miles
at 7 A.M. due to a distant haze. Conditions are fair
and dry despite the strong winds, with dew points
moving down to the mid 20’s.

The high so far today is 44F, which is 5 degrees above
the daily normal maximum of 39F. The low since midnight
is 40F, which is 16 degrees above the normal minimum
of 24F.

PRELIMINARY STATS FOR NOVEMBER 2019

TEMPERATURE, Deg. F
Avg. Max. 46.0 [-4.0] Avg. Min. 30.3 [-3.2] Mean      38.2 [-3.5] 24-hour corrected mean: 38.0
Max. for month: 67F on the 1st
Min. for month: 15F on the 13th

HEATING DEGREE DAYS
Total heating units:    761 [+99] Total for the season:  1237 [-24] Total for last season: 1319

PRECIPITATION, Inches
Total: 3.74 [-1.02] Greatest in 24 hrs: 1.60 ins. on the 24th

SNOWFALL, Inches
Total: 0.1 [-2.2] Greatest in 24 hrs: 0.1 ins. on the 12th

WIND, mph
Avg. uncorrected wind speed: 12.5 mph
Avg. corrected wind speed:   12.9 mph
Prevailing wind direction:   W [16%] Peak gust and direction:     67 S on the 1st

SUNSHINE:
Campbell-Stokes card minutes: 8652 minutes of possible 17010 or 51%
Astronomical total minutes: 8985 minutes of possible 17640 or 51%

Today’s Observations:

7 A.M.
Weather: Broken altostratus
Temperature: 40F; Dew Point: 28F; Wind: W at 22G25 kts,
Peak wind: 41 MPH (36 kts) WSW at 6:16 A.M.
Sea-level pressure: 29.43 ins. Hg, rising rapidly
Visibility: 35 miles, distant haze
Snow Depth: 0 ins.
BHO SA 1155 E120 BKN 35 966/40/28/2622G25/943/ DSNT HZ
ALQDS PK WND 2536/16/ 8/010 70043 51040 10048 20040

10 A.M.
Weather: Broken cumulus
Temperature: 42F; Dew Point: 25F; Wind: W at 23G33 kts,
Peak wind: 48 MPH (42 kts) W at 9:30 A.M.
Sea-level pressure: 29.95 ins. Hg, rising rapidly
Visibility: 75 miles
3-hr Precip: 0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 E50 BKN 75 007/42/25/2723G33/955/ PK WND
2742/30/ 8/100 51041

1 P.M.
Weather: Broken stratocumulus
Temperature: 43F; Dew Point: 24F; Wind: W at 17G38 kts,
Peak wind: 53 MPH (46 kts) W at 11:48 A.M.
Sea-level pressure: 29.60 ins. Hg, rising steadily
Visibility: 65 miles
6-hr Max temp: 44F
6-hr Min temp: 40F
6-hr Precip:  0.00 ins.
Snow Depth: 0 ins.
BHO SA 1755 E60 BKN 65 024/43/24/2717G38/960/ PK WND
2746/1548/ 8/400 53017 10044 20040

SUMMARY FOR SATURDAY, DECEMBER 14, 2019

TEMPERATURE (DEGREES F)
MAX…..58   NORMAL…..40
MIN…..46   NORMAL…..25
MEAN….52   NORMAL…..32

DEPARTURE FROM 30-YEAR NORMAL…………………+20
TOTAL DEPARTURE FOR THE MONTH…………………-22 [-1.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………13  DEPARTURE…….-20
TOTAL HEATING UNITS FOR THE MONTH…………..453  DEPARTURE…….+21
TOTAL HEATING UNITS FOR THE SEASON…………1690  DEPARTURE……..-3
TOTAL HEATING UNITS LAST SEASON TO DATE…….1796  DEPARTURE……-106

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..45 S   AT  7:32 P.M.
AERO…………………….41 S   AT  7:24 P.M.
ASOS…………………….46 S   AT  7:31 P.M.
DAVIS……………………51 S   AT  7:22 P.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….29 S   AT  7:27 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….32 S   AT  7:29 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………30 S   AT  7:27 P.M.
AVERAGE WIND SPEED AND DIRECTION……………19.1 S
ASOS……………………18.4
DAVIS…………………..18.5 SSE [167 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.43  DEPARTURE……+0.27
ASOS…………..0.56
TOTAL PRECIPITATION FOR THE MONTH……….5.27  DEPARTURE……+2.97
ASOS…………..5.75
TOTAL PRECIPITATION FOR THE YEAR……….54.35  DEPARTURE……+3.51
ASOS………….55.15

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.4
TOTAL SNOWFALL FOR THE MONTH……………18.0  DEPARTURE……+13.1
TOTAL SNOWFALL FOR THE SEASON…………..18.1  DEPARTURE……+10.6

PRELIMINARY CLIMATE SUMMARY FOR NOVEMBER 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

11/01  67/35/51/+5/0.12/0.0/534/86            67 S   AERO M  M   RMY N/A
11/02  50/31/41/-5/0.00/0.0/612/99            17 WNW AERO 14 W   RMY N/A
11/03  53/35/44/-2/0.00/0.0/567/92            25 WSW AERO 23 W   RMY 26
11/04  53/33/43/-2/0.00/0.0/546/89            24 S   AERO 20 S   RMY 24
11/05  54/44/49/+4/0.33/0.0/000/00            22 S   AERO 18 WNW RMY 28
11/06  51/36/44/-1/0.00/0.0/596/98            28 WSW AERO 23 W   RMY 27
11/07  55/38/47/+2/0.27/0.0/000/00            30 S   AERO 26 SSW RMY 32
11/08  38/23/31/-13/0.00/0.0/555/92           38 NW  AERO 37 WNW RMY 44
11/09  39/20/30/-14/0.00/0.0/583/97           22 S   AERO 18 S   RMY N/A
11/10  51/30/41/-3/0.00/0.0/174/29            30 SW  AERO 30 SW  RMY 31
11/11  52/39/46/+3/T/0.0/000/00               23 NE  AERO 22 NE  RMY 23
11/12  42/20/31/-12/0.08/0.1/000/00           37 WNW AERO 37 WNW RMY 41
11/13  28/15/22/-21/0.00/0.0/592/100          32 WNW AERO 32 WNW RMY 35
11/14  36/17/28/-14/0.00/0.0/136/23           18 SW  AERO 17 SW  RMY 20
11/15  51/32/42/0/0.00/0.0/553/94             25 WNW AERO 25 WNW RMY N/A
11/16  35/22/29/-13/0.00/0.0/580/99           35 NNW AERO 35 NNW RMY N/A
11/17  40/21/31/-10/T/T/000/00                28 ENE AERO 27 ENE RMY 29
11/18  36/32/34/-7/0.45/0.0/000/00            28 NNE AERO 29 N   RMY 31
11/19  42/36/39/-2/0.22/0.0/000/00            12 SSW AERO  9 NNW RMY N/A
11/20  38/33/36/-4/0.23/T/000/00              20 NW  AERO 18 NW  RMY 21
11/21  46/30/38/-2/0.00/0.0/536/93            21 NW  AERO 21 NW  RMY N/A
11/22  52/32/42/+2/0.13/0.0/000/00            46 W   AERO 47 W   RMY 47
11/23  44/27/36/-3/0.00/0.0/503/88            29 WNW AERO 29 WNW RMY N/A
11/24  44/35/40/+1/1.60/0.0/000/00            45 N   AERO 44 NE  RMY 46 TSTM
11/25  50/34/42/+3/0.00/0.0/329/58            32 WNW AERO 35 WNW RMY 23
11/26  59/39/49/+11/0.00/0.0/544/96           28 SSW AERO 27 SSW RMY 29
11/27  50/42/46/+8/0.24/0.0/011/02            30 W   AERO 32 W   RMY N/A TSTM
11/28  48/30/39/+1/0.07/T/062/11              42 NW  AERO 44 NW  RMY 44
11/29  39/27/33/-4/0.00/0.0/433/77            35 NW  AERO 36 NW  RMY 39
11/30  35/22/29/-8/0.00/0.0/539/96            30 NW  AERO 28 WNW RMY 31

DAILY RECORDS FOR NOVEMBER

11/13/19: DAILY RECORD LOW MAXIMUM TEMPERATURE OF 28F,
BREAKS PREVIOUS RECORD OF 30F SET IN 1920.
It was also the third earliest maximum temperature
colder than 30F on record, behind only 28F on 11/8/1894
and 29F on 11/12/1894.

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  32/16/24/-13/…./5.8/…/..           33 ENE AERO 32 ENE RMY N/A
12/02  37/25/31/-5/…./2.7/…/..            52 NE  AERO 47 NE  RMY 53
12/03  30/23/27/-9/…./4.6/…/..            32 N   AERO 35 N   RMY 36
12/04  34/22/28/-7/…./0.0/…/..            23 WNW AERO 23 NNW RMY N/A
12/05  41/26/34/-1/…./0.0/…/..            33 NW  AERO 35 NW  RMY 37
12/06  33/23/28/-7/0.02/0.1/…/..            25 NW  AERO 23 NW  RMY 29
12/07  31/18/25/-9/0.00/0.0/…/..            25 NW  AERO 23 NW  RMY N/A
12/08  36/15/26/-8/0.00/0.0/…/..            31 SSW AERO 32 SSW RMY N/A
12/09  57/36/47/+13/…./0.0/…/..           53 S   AERO 52 S   RMY 54
12/10  58/37/48/+15/…./0.0/…/..           35 SW  AERO 39 SW  RMY N/A
12/11  36/23/30/-3/…./0.0/…/..            25 NW  AERO 25 NW  RMY N/A
12/12  29/17/23/-10/…./0.0/…/..           29 W   AERO 30 W   RMY 25
12/13  46/22/34/+2/…./0.0/…/..            25 SSE AERO 25 SSE RMY N/A
12/14  58/46/52/+20/…./0.0/…/..           45 S   AERO 41 S   RMY N/A

12/15 The low since midnight is 40F, daily normal minimum is 24F

DAILY RECORDS FOR DECEMBER

12/01/19: DAILY RECORD SNOWFALL OF 5.8 INS.,
BREAKS PREVIOUS RECORD OF 2.0 INS. SET IN 1902.

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

RECORDS FOR DECEMBER 15
HIGH 64 IN 1975
LOW 4 IN 1900, 1905, 1933
PRECIP 1.80 INS. IN 1981
SNOW 7.5 INS. IN 1951
PEAK GUST 65 MPH NW IN 1991

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

TODAY’S REPORT PREPARED BY: Benjamin Turner