Friday, December 6, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 6, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

AN OVERCAST MORNING WITH GOOD VISIBILITY
LED TO LIGHT SNOW THIS AFTERNOON….

Today began cloudy with around 75 miles of visibility,
but dropped after noontime due to approaching snow
showers. Light snow has fallen since 2 P.M., leaving
a small coating on the ground and trees. Wind has been
lighter in comparison to yesterday, blowing in from the
southwest.

The high so far today is 32F, which is 10 degrees below the
daily normal maximum of 42F. The low since midnight is 23F,
which is 4 degrees below the normal minimum of 27F.

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: N/A

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: N/A
Astronomical total minutes:   N/A

Today’s Observations:

7 A.M.
Weather: Scattered altocumulus, broken cirrostratus
Temperature: 25F; Dew Point: 17F; Wind: WSW at 9 kts
Sea-level pressure: 30.08 ins. Hg, rising, then more slowly
Visibility: 75 miles
6-hr Max temp: 26F
6-hr Min temp: 23F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 140 SCT E250 BKN 75 187/25/17/2509/008/ 8/078
4/005 51015 10026 20023

10 A.M.
Weather: Overcast altocumulus, distant virga NE-S
Temperature: 29F; Dew Point: 19F; Wind: SW at 9 kts
Sea-level pressure: 30.09 ins. Hg, rising, then more slowly
Visibility: 75 miles
3-hr Precip: 0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 E95 OVC 75 191/29/19/2309/009/ DSNT VIRGA NE-S/
8/07/ 50004

1 P.M.
Weather: Overcast altostratus
Temperature: 32F; Dew Point: 20F; Wind: SW at 10 kts
Sea-level pressure: 30.03 ins. Hg, falling steadily
Visibility: 35 miles
6-hr Max temp: 32F
6-hr Min temp: 25F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 E70 OVC 35 168/32/20/2210/003/ 8/02/ 4/005
58023 10032 20025

SUMMARY FOR THURSDAY, DECEMBER 5, 2019

TEMPERATURE (DEGREES F)
MAX…..41   NORMAL…..43
MIN…..26   NORMAL…..27
MEAN….34   NORMAL…..35

DEPARTURE FROM 30-YEAR NORMAL………………… -1
TOTAL DEPARTURE FOR THE MONTH…………………-35 [-7.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………31  DEPARTURE……..+1
TOTAL HEATING UNITS FOR THE MONTH…………..181  DEPARTURE…….+35
TOTAL HEATING UNITS FOR THE SEASON…………1418  DEPARTURE…….+10
TOTAL HEATING UNITS LAST SEASON TO DATE…….1462  DEPARTURE…….-44

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..33 NW  AT 11:30 P.M.
AERO…………………….35 NW  AT 11:30 P.M.
ASOS…………………….35 WNW AT 11:30 P.M.
DAVIS……………………36 WNW AT 11:29 P.M. RMY 37
FASTEST MILE FOR YESTERDAY………………….27 NW  AT 11:32 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….24 NW  AT 11:35 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………27 WNW AT 11:29 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..14.7 W
ASOS…………………..14.3
DAVIS………………….15.3 W [282 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……….2.43  DEPARTURE……+1.61
ASOS…………..2.57
TOTAL PRECIPITATION FOR THE YEAR……….51.51  DEPARTURE……+2.15
ASOS………….51.97

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.3
TOTAL SNOWFALL FOR THE MONTH……………13.1  DEPARTURE……+11.7
TOTAL SNOWFALL FOR THE SEASON…………..13.2  DEPARTURE…….+9.2

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  The low since midnight is 23F, daily normal minimum is 27F

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 6
HIGH 70 IN 2001
LOW 5 IN 1901,1935
PRECIP 2.78 INS. IN 2003
SNOWFALL 17.0 INS. IN 2003
PEAK GUST 74 MPH NW IN 1981

RECORDS FOR DECEMBER 7
HIGH 74 IN 1998
LOW 6 IN 1906
PRECIP 1.67 INS. IN 1953
SNOWFALL 6.3 INS. IN 2003
PEAK GUST 76e SE IN 1976

TODAY’S REPORT PREPARED BY: Benjamin Turner