Saturday, December 21, 2019
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 21, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME
INCREASING CLOUDS AND SLIGHTLY WARMER TODAY…
After some filtered sunshine this morning, denser high clouds
and some lower clouds have filled the sky by mid-day. The
temperature has climbed back to the low 30’s for the first time
since Wednesday after a chilly start at 16F this morning.
Visibility started very good at 70-75 miles in many directions
early today, but it has dropped to about 40 miles by afternoon.
Winds have been very light today with a peak gust so far of
only 15 mph from the NNW shortly after midnight.
The high so far today is 30F, which is 7 degrees below the
daily normal maximum of 37F. The low since midnight is 16F,
which is 6 degrees below the normal minimum of 22F.
Today’s Observations:
7 A.M.
Weather: Thin scattered cirrus fibratus, few altocumulus
distant NE-S, few lower dense cirrus SE-S
Temperature: 17F; Dew Point: 11F; Wind: NNW at 7 kts
Sea-level pressure: 30.64 ins. Hg, falling then rising now higher
Visibility: 75 miles
6-hr Max temp: 18F
6-hr Min temp: 16F
24-hr Precip: 0.00 ins.
24-hr Snowfall: 0.0 ins.
Snow Depth: Trace
BHO SA 1155 E250 SCT 75 375/17/11/3407/064/ FEW AC DSNT NE-S
FEW LWR DNS CI SE-S/ 8/071 53002 10018 20016
10 A.M.
Weather: Scattered stratocumulus, overcast cirrostratus and
cirrus fibratus, few altocumulus, few lower dense cirrus SE-S,
breaks in overcast distant NNW-N, thin spots in overcast all
quadrants, partial halo
Temperature: 26F; Dew Point: 13F; Wind: calm at 0 kts,
Sea-level pressure: 30.65 ins. Hg, rising slowly
Visibility: 70 miles
3-hr Precip: 0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 10 SCT 250 OVC 70 380/26/13/0000/065/ FEW AC
FEW LWR DNS CI SE-S BINOVC DSNT NNW-N THN SPTS IOVC ALQDS
PARTIAL HALO VSBY NE-ENE 55/ 8/577 53005
1 P.M.
Weather: Scattered stratocumulus, broken cirrostratus,
overcast cirrus fibratus, few altocumulus, thin spots in
overcast, sun dimly visible
Temperature: 30F; Dew Point: 22F; Wind: S at 5 kts,
Wind: Light
Sea-level pressure: 30.57 ins. Hg, falling then more quickly
Visibility: 40 miles
6-hr Max temp: 30F
6-hr Min temp: 17F
6-hr Precip: 0.00 ins.
6-hr Snowfall: 0.0 ins.
Snow Depth: Trace
BHO SA 1755 25 SCT 200 BKN 230 OVC 40 353/30/22/1705/057/
FEW AC FEW THN SPTS IOVC SUN DMLY VSBL WND LGT/ 8/578
58027 10030 20017
SUMMARY FOR FRIDAY, DECEMBER 20, 2019
TEMPERATURE (DEGREES F)
MAX…..29 NORMAL…..38
MIN…..11 NORMAL…..22
MEAN….20 NORMAL…..30
DEPARTURE FROM 30-YEAR NORMAL…………………-10
TOTAL DEPARTURE FOR THE MONTH…………………-51 [-2.8 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………45 DEPARTURE…….+10
TOTAL HEATING UNITS FOR THE MONTH…………..687 DEPARTURE…….+49
TOTAL HEATING UNITS FOR THE SEASON…………1924 DEPARTURE…….+24
TOTAL HEATING UNITS LAST SEASON TO DATE…….1975 DEPARTURE…….-51
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..32 W AT 3:34 A.M.
AERO…………………….30 W AT 3:34 A.M.
ASOS…………………….33 W AT 3:34 A.M.
DAVIS……………………33 W AT 3:31 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….23 NW AT 9:20 A.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE……………….22 NW AT 9:22 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………23 WNW AT 3:58 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..13.3 NW
ASOS…………………..13.2
DAVIS………………….13.6 NW [308 deg.]
* Last of several occurrences
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……+2.82
ASOS…………..6.51
TOTAL PRECIPITATION FOR THE YEAR……….55.14 DEPARTURE……+3.36
ASOS………….55.91
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0 DEPARTURE…….-0.6
TOTAL SNOWFALL FOR THE MONTH……………19.1 DEPARTURE……+11.3
TOTAL SNOWFALL FOR THE SEASON…………..19.2 DEPARTURE…….+8.8
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/…./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 The low since midnight is 16F, daily normal minimum is 22F
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 21
HIGH 60 IN 1957
LOW -10 IN 1942
PRECIP 2.01 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957
RECORDS FOR DECEMBER 22
HIGH 63 IN 2013
LOW -5 IN 1921
PRECIP 1.52 INS. IN 1975
SNOWFALL 8.8 INS. IN 1975
PEAK GUST 62 MPH WNW IN 1998
TODAY’S REPORT PREPARED BY: Mike Iacono
