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

SUNDAY, OCTOBER 25, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

MUCH COOLER TODAY FOLLOWING A COLD FRONTAL PASSAGE LATE
YESTERDAY, LOTS OF CLOUDS LINGERING AS WELL…

What a difference a day makes. After temperatures reaching
the upper 60s yesterday, we’ve only briefly made it to 50
so far today. A cold front came through late yesterday
shifting the wind from generally southwesterly to north-
northwesterly. Temperatures fell steadily last evening from
the low 60s to the low 40s by midnight.

A gusty north-northwest wind also developed helping to
usher in the cooler air mass.

Today we’ve seen mainly cloudy skies with the wind starting
the day out of the north-northwest, but has gradually veered
over to the east-northeast by early this afternoon. The
combination of the onshore wind and cloud cover has helped
to hold temperatures mainly in the 40s here on the summit,
although we did briefly touch 50 degrees, which as been the
maximum so far.

As mentioned, the high so far today is 50F, this is 7 degrees
below the daily normal maximum of 57F. The low since midnight
is 40F, which is exactly normal for the date.

Today’s Observations:

7 A.M.
Weather: Broken stratocumulus, broken altocumulus,
broken cirrus/cirrostratus
Temperature: 42F; Dew Point: 31F; Relative Humidity: 64%
Wind: NNW at 10G17 kts
Sea-level pressure: 30.21 ins. Hg: rising unsteadily
Visibility: 70
6-hr Max temp: 42F
6-hr Min temp: 40F
24-hr Precip: 0.00 ins.
BHO SA 1155 E35 BKN 120 BKN 250 BKN 70 229/42/31/3410G17/021/
8/538 52026 10042 20040

10 A.M.
Weather: Overcast stratocumulus, few breaks in overcast distant
NW-NNW, thin spots in overcast all quadrants
Temperature: 47F; Dew Point: 35F; Relative Humidity: 62%
Wind: N at 6 kts, wind light and variable
Sea-level pressure: 30.24 ins. Hg: rising unsteadily
Visibility: 70 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 E35 OVC 70 242/47/35/0106/024/ FEW BINOVC DSNT NW-NNW
FEW THN SPTS IOVC ALQDS SUN OCLY DMLY VSBL WND L/V/ 8/5// 52013

1 P.M.
Weather: Overcast stratocumulus, few thin spots in overcast all
quadrants, sun occasionally dimly visible
Temperature: 49F; Dew Point: 36F; Relative Humidity: 60%
Wind: ENE at 7 kts
Sea-level pressure: 30.25 ins. Hg: rising, then falling
Visibility: 70 miles
6-hr Max temp: 50F
6-hr Min temp: 42F
6-hr Precip: 0.00 inches
BHO SA 1755 E35 OVC 70 244/49/36/0707/025/ FEW THN SPTS IOVC ALQDS
HIR CLDS OCLY VSBL SUN OCLY DMLY VSBL/ 8/5// 50002 10050 20042

SUMMARY FOR SATURDAY, OCTOBER 24, 2020

TEMPERATURE (DEGREES F)
MAX…..68 NORMAL…..58
MIN…..42 NORMAL…..40
MEAN….55 NORMAL…..49

DEPARTURE FROM 30-YEAR NORMAL……………. +6
TOTAL DEPARTURE FOR THE MONTH…………….+98 [+3.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….10 DEPARTURE….. -6
TOTAL HEATING UNITS FOR THE MONTH…………196 DEPARTURE….-103
TOTAL HEATING UNITS FOR THE SEASON………..294 DEPARTURE….-147
TOTAL HEATING UNITS LAST SEASON TO DATE……364 DEPARTURE…..-70

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………. 0 DEPARTURE…… 0
TOTAL COOLING UNITS FOR THE MONTH…………. 1 DEPARTURE….. -4
TOTAL COOLING UNITS FOR THE SEASON………..831 DEPARTURE….+229
TOTAL COOLING UNITS LAST SEASON TO DATE……682 DEPARTURE….+149

PEAK WIND GUST FOR YESTERDAY (MPH)
420C/Official……………32 NNW AT 9:57 P.M.
AEROVANE (south tower)……32 NNW AT 8:48 P.M.
ASOS……………………32 NW AT 9:31 P.M
DAVIS #1………………..31 NW AT 9:31 P.M
DAVIS #2 (south tower)……30 N AT 9:33 P.M
RMY…………………….32
MERLIN………………….30

FASTEST MILE FOR YESTERDAY…………………23 NNW AT 9:30 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………21 NW AT 9:35 P.M
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE…………..22 NNW AT 9:32 P.M
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE…………..22 NNW AT 8:54 P.M
AVERAGE WIND SPEED AND DIRECTION…………. 9.9 NNW [237 total miles] ASOS………………….10.2
DAVIS #1………………10.1 W [272 deg.] DAVIS #2………………10.4 W [267 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00 DEPARTURE….-0.15
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….4.20 DEPARTURE….+0.61
ASOS…………..4.18
TOTAL PRECIPITATION FOR THE YEAR……….38.62 DEPARTURE….-4.05
ASOS………….39.39

PRELIMINARY CLIMATE SUMMARY FOR OCTOBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/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

10/01 75/56/66/+9/0.00/591/84 28 SW AERO 28 SW RMY N/A
10/02 63/49/56/-1/0.02/203/29 20 NW AERO 21 NW RMY 20
10/03 65/45/55/-1/0.00/676/97 19 WNW AERO 19 WNW RMY 19
10/04 65/45/55/-1/0.00/659/95 17 ESE AERO 18 ESE RMY 18
10/05 62/52/57/+1/0.00/277/40 17 ENE AERO 17 ENE RMY N/A
10/06 69/51/60/+5/0.00/503/73 28 S AERO 28 S RMY 29
10/07 73/50/62/+7/0.14/316/46 76 W AERO 74 W RMY 70 TSTM
10/08 61/42/52/-2/0.00/676/99 41 W AERO 41 W RMY N/A
10/09 60/37/49/-5/0.00/646/95 25 SSW AERO 28 SSW RMY N/A
10/10 75/52/64/+10/0.00/549/81 40 SSW AERO 40 SSW RMY 38
10/11 64/47/56/+3/0.00/574/85 32 NNW AERO 35 NNW RMY N/A
10/12 52/48/50/-3/T/000/00 28 E AERO 27 E RMY N/A
10/13 57/49/53/0/1.74/000/00 32 E AERO 33 E RMY N/A
10/14 67/47/57/+5/0.00/…/.. 23 WNW AERO 25 WNW RMY N/A
10/15 71/50/61/+9/0.00/…/.. 43 S AERO 46 S RMY 42
10/16 68/48/58/+7/1.00/…/.. 28 S AERO 30 S RMY N/A
10/17 56/39/48/-3/1.24/…/.. 35 WNW AERO 40 WNW RMY 37
10/18 60/46/53/+2/0.00/…/.. 20 ESE AERO 21 ESE RMY 20
10/19 61/46/54/+4/0.00/…/.. 16 ESE AERO 16 SSE RMY N/A
10/20 66/49/58/+8/0.00/…/.. 22 S AERO 22 S RMY 22
10/21 71/56/64/+14/0.06/…/.. 26 SSW AERO 26 SSW RMY 26
10/22 70/54/62/+13/0.00/…/.. 18 SSW AERO 17 SSW RMY N/A
10/23 68/52/60/+11/0.00/…/.. 18 ESE AERO 18 ESE RMY 18
10/24 68/42/55/+6/0.00/…/.. 32 NNW AERO 32 NNW RMY 32