Tuesday, December 31, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, DECEMBER 31, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

A VERY FOGGY NEW YEARS’ EVE WITH SOME LIGHT
RAIN IN THE MORNING HOURS….

Following yesterday’s mixed precipitation, the final
measurement for snowfall was 0.8 inches; all falling
yesterday afternoon. The liquid total for this wintry
mix event is 1.75 inches, with rain stopping shortly
after 11 A.M. today. The observatory has seen less
than a 1/2 mile of visibility all day, due to a thick,
persistent fog.

Wind has shifted from E-WNW early this morning, causing
a steady drop in temperature since then. The low since
midnight is 33F, 14 degrees above the normal low of 19F.
The high so far today is 40F, 5 degrees below the daily
normal maximum of 35F.

From all of us at Blue Hill Weather Observatory, we wish
you a happy new year!

Today’s Observations:

7 A.M.
Weather: Light rain
Temperature: 39F; Dew Point: 39F; Wind: NNE at 16G23 kts
Sea-level pressure: 29.63 ins. Hg, falling, then more slowly
Visibility: 1/16 mile, fog
6-hr Max temp: 39F
6-hr Min temp: 36F
24-hr Precip:  1.23 ins.
24-hr Snowfall: 0.8 ins.
Snow Depth: Trace
BHO SA 1155 X W3 1/16R-F 035/39/39/0316G23/963/ NEW SNOW PAST
24 HOURS 0.5 INS R-CTD/ 8//// 70123 56023 10039 20036

10 A.M.
Weather: Light rain
Temperature: 34F; Dew Point: 34F; Wind: NW at 13G21 kts
Sea-level pressure: 29.61 ins. Hg, steady, then falling
Visibility: 1/16 mile, fog
3-hr Precip:  0.04 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 X W3 1/16R-F 028/34/34/3313G21/961/ R-CTD/ 8////
6004/ 56007

1 P.M.
Weather: Fog
Temperature: 34F; Dew Point: 34F; Wind: WNW at 9 kts
Sea-level pressure: 29.55 ins. Hg, falling, then more slowly
Visibility: 1/16 mile, fog
6-hr Max temp: 40F
6-hr Min temp: 33F
6-hr Precip:  0.04 ins.
6-hr Snowfall: 0.0 ins.
Snow Depth: Trace
BHO SA 1755 X W3 1/16R-F 010/34/34/3009/955/ 8//// 6004/ 56018
10040 20033

SUMMARY FOR MONDAY, DECEMBER 30, 2019

TEMPERATURE (DEGREES F)
MAX…..36   NORMAL…..35
MIN…..32   NORMAL…..19
MEAN….34   NORMAL…..27

DEPARTURE FROM 30-YEAR NORMAL………………… +7
TOTAL DEPARTURE FOR THE MONTH…………………+18 [+0.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………31  DEPARTURE……. -7
TOTAL HEATING UNITS FOR THE MONTH…………..985  DEPARTURE…….-20
TOTAL HEATING UNITS FOR THE SEASON…………2222  DEPARTURE…….-45
TOTAL HEATING UNITS LAST SEASON TO DATE…….2265  DEPARTURE…….-43

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..40 E   AT  9:52 A.M.
AERO…………………….37 E   AT  8:24 A.M.
ASOS…………………….40 E   AT  9:53 A.M.
DAVIS……………………39 E   AT  2:34 P.M. RMY 37
FASTEST MILE FOR YESTERDAY………………….31 E   AT  9:53 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….29 E   AT  9:53 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………31 E   AT  9:51 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..16.6 E
ASOS…………………..16.8
DAVIS………………….16.7 E [93 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….1.23  DEPARTURE……+1.09
ASOS…………..1.27
TOTAL PRECIPITATION FOR THE MONTH……….7.77  DEPARTURE……+3.01
ASOS…………..8.24
TOTAL PRECIPITATION FOR THE YEAR……….56.85  DEPARTURE……+3.55
ASOS………….57.64

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.8  DEPARTURE…….+0.3
TOTAL SNOWFALL FOR THE MONTH……………19.9  DEPARTURE…….+7.1
TOTAL SNOWFALL FOR THE SEASON…………..20.0  DEPARTURE…….+4.6

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/…./5.8/011/02           33 ENE AERO 32 ENE RMY N/A
12/02  37/25/31/-5/…./2.7/000/00            52 NE  AERO 47 NE  RMY 53
12/03  30/23/27/-9/…./4.6/000/00            32 N   AERO 35 N   RMY 36
12/04  34/22/28/-7/…./0.0/000/00            23 WNW AERO 23 NNW RMY N/A
12/05  41/26/34/-1/…./0.0/343/62            33 NW  AERO 35 NW  RMY 37
12/06  33/23/28/-7/0.02/0.1/000/00            25 NW  AERO 23 NW  RMY 29
12/07  31/18/25/-9/0.00/0.0/519/94            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/…./3.0/…/..            25 NW  AERO 25 NW  RMY N/A
12/12  29/17/23/-10/…./1.8/…/..           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  48/28/38/+6/0.00/0.0/…/..            53 W   AERO 53 W   RMY 50
12/16  30/25/28/-3/0.00/0.0/…/..            36 W   AERO 36 W   RMY N/A
12/17  35/23/29/-2/…./1.0/…/..            22 NNW AERO 21 NE  RMY 23
12/18  33/18/26/-5/…/0.0/…/..             44 WNW AERO 45 WNW RMY N/A
12/19  20/9/15/-15/…/0.0/…/..             51 W   AERO 47 W   RMY N/A
12/20  29/11/20/-10/0.00/0.0/…./..          32 W   AERO 30 W   RMY 29
12/21  31/16/24/-6/0.00/0.0/…./..           16 SSE AERO 15 SSE RMY N/A
12/22  40/26/33/+4/0.00/0.0/…./..           23 SW  AERO 21 SW  RMY 23
12/23  54/33/44/+15/0.00/0.0/…./..          30 WSW AERO 30 SW  RMY 30
12/24  42/29/36/+7/0.00/0.0/…./..           30 NW  AERO 27 NW  RMY 30
12/25  42/25/34/+6/0.00/0.0/…./..           16 NNE AERO 16 N   RMY N/A
12/26  39/29/34/+6/0.00/0.0/…./..           22 ENE AERO 20 ENE RMY 22
12/27  47/31/39/+11/0.00/0.0/…./..          32 SSW AERO 30 SSW RMY 34
12/28  47/30/39/+11/0.00/0.0/…./..          23 W   AERO 22 W   RMY N/A
12/29  42/28/35/+8/…./0.0/…./..           22 WNW AERO 21 WNW RMY 23
12/30  36/32/34/+7/…./0.8/…./..           40 E   AERO 37 E   RMY 37

12/31 The low since midnight is 33F, daily normal minimum is 19F

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 31
HIGH 62 IN 1965
LOW -12 IN 1917
PRECIP 0.96 INS. IN 1906
SNOWFALL 7.5 INS. IN 2008
PEAK GUST 78 MPH NW IN 1990

RECORDS FOR JANUARY 1
HIGH 58F IN 1966
LOW -6F IN 1918
PRECIP 1.45 INS. IN 1982
SNOWFALL 7.2 INS. IN 1938
PEAK GUST 90e MPH S IN 1945

TODAY’S REPORT PREPARED BY: Benjamin Turner