Saturday, December 14, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 14, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM AND RAINY WITH QUICKLY DECREASING
PRESSURE….

We observed very limited visibility, fluctuating between
a 1/2 mile and a 1/16th mile due to fog. Rain overnight
left 1.03 inches in the gauge this morning, and another
0.42 inches fell between 7 A.M. and 1 P.M. Pressure has
decreased sharply, by almost 25 millibars since midnight.
Wind has shifted from southeast to south, blowing at an
average of 20 mph. The highest gust so far today is 37
mph, at around 4 A.M.

Weather conditions feel almost tropical in comparison to
days ago. The high so far today is 58F, which is 18 degrees
above the daily normal maximum of 40F. The low since midnight
is 46F, which is 22 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: 1.66 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: Light rain
Temperature: 54F; Dew Point: 54F; Wind: SE at 17G24 kts
Sea-level pressure: 29.60 ins. Hg, decreasing rapidly
Visibility: 1/2 mile, fog
Snow Depth: 0 ins.
BHO SA 1155 X W3 1/2R-F 025/54/54/1417G24/960/ R-CTD/
8//// 70103 56064 10054 20046

10 A.M.
Weather: Light rain
Temperature: 56F; Dew Point: 56F; Wind: SE at 15G21 kts
Sea-level pressure: 29.47 ins. Hg, decreasing rapidly
Visibility: 1/16 miles, fog
3-hr Precip: 0.35 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 X W3 1/16R-F 979/56/56/1515G21/947/ R-CTD/
8//// 6035/ 58046

1 P.M.
Weather: Drizzle
Temperature: 58F; Dew Point: 58F; Wind: S at 8 kts
Sea-level pressure: 29.35 ins. Hg, decreasing rapidly
Visibility: 1/16 mile, fog
6-hr Max temp: 58F
6-hr Min temp: 54F
6-hr Precip:  0.42 ins.
Snow Depth: 0 ins.
BHO SA 1755 X W3 1/16LF 940/58/58/1908/935/ L CTD/ 8////
6042/ 56039 10058 20054

SUMMARY FOR FRIDAY, DECEMBER 13, 2019

TEMPERATURE (DEGREES F)
MAX…..46   NORMAL…..40
MIN…..22   NORMAL…..25
MEAN….34   NORMAL…..32

DEPARTURE FROM 30-YEAR NORMAL………………….+2
TOTAL DEPARTURE FOR THE MONTH…………………-42 [-3.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………31  DEPARTURE……..-2
TOTAL HEATING UNITS FOR THE MONTH…………..440  DEPARTURE…….+42
TOTAL HEATING UNITS FOR THE SEASON…………1677  DEPARTURE…….+17
TOTAL HEATING UNITS LAST SEASON TO DATE…….1768  DEPARTURE…….-91

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..25 SSE AT  7:22 A.M.
AERO…………………….25 SSE AT  7:02 A.M.
ASOS…………………….25 ESE AT 10:48 P.M.
DAVIS……………………26 SSE AT  6:41 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….22 SSE AT  7:44 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….18 ESE AT 11:11 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………20 SE  AT  6:41 A.M.
AVERAGE WIND SPEED AND DIRECTION……………14.0 SE
ASOS……………………13.3
DAVIS…………………..14.4 SE [139 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….1.03  DEPARTURE……+0.87
ASOS…………..1.10
TOTAL PRECIPITATION FOR THE MONTH……….4.84  DEPARTURE……+2.70
ASOS…………..5.19
TOTAL PRECIPITATION FOR THE YEAR……….53.92  DEPARTURE……+3.24
ASOS………….54.59

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.5
TOTAL SNOWFALL FOR THE MONTH……………18.0  DEPARTURE……+13.5
TOTAL SNOWFALL FOR THE SEASON…………..18.1  DEPARTURE……+11.0

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/…./0.0/000/00            28 NNE AERO 29 N   RMY 31
11/19  42/36/39/-2/…./0.0/000/00            12 SSW AERO  9 NNW RMY N/A
11/20  38/33/36/-4/…./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/+2/0.12/0.0/000/00            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/+1/1.49/0.0/000/00            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/…./0.0/011/02            30 W   AERO 32 W   RMY N/A TSTM
11/28  48/30/39/+1/…./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 The low since midnight is 46F, 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 14
HIGH 62 IN 1901
LOW -6 IN 1893
PRECIP 1.94 INS. IN 2002
SNOWFALL 8.0 INS. IN 1907
PEAK GUST 78e ENE IN 1941

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

TODAY’S REPORT PREPARED BY: Benjamin Turner