Monday, December 23, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, DECEMBER 23, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM AND MOSTLY SUNNY, WITH VISIBILITY INCREASING
IN THE AFTERNOON….

Today we observed partly cloudy skies with abundant
sunshine. Visibility was limited to less than
25 miles this morning due to haze, but increased to
65 miles after noontime. Wind was consistent, at a
speed of 10 mph from the southwest. Pressure has
started to steadily drop since this morning; by about 4
millibars. Humidity dropped, as dew points stayed in
the low 30’s while temperatures exceeded 50 degrees
by 1 P.M.

The high so far today is 52F, which is 15 degrees above
the daily normal maximum of 37F. The low since midnight
is 33F, which is 12 degrees above the normal minimum
of 21F.

Today’s Observations:

7 A.M.
Weather: Clear, few stratocumulus
Temperature: 33F; Dew Point: 29F; Wind: WSW at 10 kts
Sea-level pressure: 30.08 ins. Hg, falling then rising
Visibility: 20 miles, hazy
6-hr Max temp: 35F
6-hr Min temp: 33F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
Snow Depth: Trace
BHO SA 1155 CLR 20 185/33/29/2410/008/ FEW SC ALQDS
HAZY/ 8/400 53003 10035 20033

10 A.M.
Weather: Scattered cirrus
Temperature: 41F; Dew Point: 32F; Wind: SW at 7 kts,
Sea-level pressure: 30.08 ins. Hg, falling then rising
Visibility: 25 miles, hazy
3-hr Precip:  0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 250 SCT 25 187/41/32/2207/008/ HAZY/ 8/002
50002

1 P.M.
Weather: Broken cirrus
Temperature: 52F; Dew Point: 32F; Wind: SW at 10 kts
Sea-level pressure: 29.96 ins. Hg, falling then more quickly
Visibility: 65 miles
6-hr Max temp: 52F
6-hr Min temp: 33F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
Snow Depth: Trace
BHO SA 1755 E250 BKN 65 147/52/32/2210/996/ 8/002 58040
10052 20033

SUMMARY FOR SUNDAY, DECEMBER 22, 2019

TEMPERATURE (DEGREES F)
MAX…..40   NORMAL…..37
MIN…..26   NORMAL…..22
MEAN….33   NORMAL…..29

DEPARTURE FROM 30-YEAR NORMAL………………….+4
TOTAL DEPARTURE FOR THE MONTH…………………-53 [-2.6 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………32  DEPARTURE……..-4
TOTAL HEATING UNITS FOR THE MONTH…………..760  DEPARTURE…….+51
TOTAL HEATING UNITS FOR THE SEASON…………1997  DEPARTURE…….+26
TOTAL HEATING UNITS LAST SEASON TO DATE…….2009  DEPARTURE…….-12

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..23 SW  AT  4:15 P.M.
AERO…………………….21 SW  AT  9:15 P.M.
ASOS…………………….23 SSW AT  4:15 P.M.
DAVIS……………………24 WSW AT  7:41 P.M. RMY 23
FASTEST MILE FOR YESTERDAY………………….17 SW  AT  7:42 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….18 SW  AT  7:50 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………18 SW  AT  7:48 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..12.9 SW
ASOS…………………..13.0
DAVIS………………….12.8 SW  [231 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.16
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….6.06  DEPARTURE……+2.51
ASOS…………..6.51
TOTAL PRECIPITATION FOR THE YEAR……….55.14  DEPARTURE……+3.05
ASOS………….55.91

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.5
TOTAL SNOWFALL FOR THE MONTH……………19.1  DEPARTURE……+10.4
TOTAL SNOWFALL FOR THE SEASON…………..19.2  DEPARTURE…….+7.9

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 The low since midnight is 33F, daily normal minimum is 21F

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 23
HIGH 62 IN 1990
LOW -1 IN 1989
PRECIP 1.70 INS. IN 1947
SNOWFALL 11.9 INS. IN 1947
PEAK GUST 67 SSE IN 2004

RECORDS FOR DECEMBER 24
HIGH 67 IN 2015
LOW -6 IN 1943
PRECIP 2.21 INS. IN 1994
SNOWFALL 12.3 INS. IN 1961
PEAK GUST 79e MPH SE IN 1941

TODAY’S REPORT PREPARED BY: Benjamin Turner and Ann Murphy