Thursday, September 10, 2020
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
THURSDAY, SEPTEMBER 10, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME
WARM, MUDDY AND OVERCAST…
The 2 big stories here at the hill today are the
warmth and humidity:
We have only managed to hit 69 degrees as the low
temperature since midnight today. If this holds
through the end of the day, this would tie for 2nd
highest minimum temperature on record for this date.
For interest, 71 degrees remains the top spot –
occurring in 2016.
The other headline is the anomalously oppressive
dew points. They have slowly inched their way upwards
from 71 degrees at 7AM to a peak of 73 degrees by
late morning. While we do not maintain strict dew
point records here at the Observatory, Boston does.
Since records commenced there in 1936, a max dew
point of 74 degrees today would tie the highest
reading so late in the season. 75 degrees would
break it. If you are wondering, 77 degrees is the
highest September dew point on record for KBOS set
on September 3rd, 1993. The average dew point this
time of year is 55 degrees -give or take- so we are
well beyond that point!
Skies have remained predominantly overcast with
limited visibility. A sprinkle here and there have
been felt in between observations. Winds continue
from the south peaking so far at 19 MPH.
The high so far today is 80F, 6 degrees above the
daily normal max of 74F. The low since midnight is
69F, which is 12 degrees above the normal low of 57F.
PRELIMINARY STATS FOR AUGUST 2020
TEMPERATURE, Deg. F
Avg. Max. 82.5 [+3.3]
Avg. Min. 64.3 [+2.5]
Mean 73.4 [+2.9]
24-hour corrected mean: 72.3
Max. for month: 94F on the 10th
Min. for month: 54F on the 31st
HEATING DEGREE DAYS
Total heating units: 2 [-14]
Total for the season: 3 [-22]
Total for last season: 12
COOLING DEGREE DAYS
Total cooling units: 270 [+84]
Total for the season: 757 [+220]
Total for last season: 622
PRECIPITATION, Inches
Total: 3.74 [-0.29]
Greatest in 24 hrs: N/A
WIND, mph
Avg. uncorrected wind speed: 10.0 mph
Avg. corrected wind speed: 10.6 mph
Prevailing wind direction: SSW [12%]
Peak gust and direction: 67 SSE on the 4th
SUNSHINE:
Campbell-Stokes card minutes: 15366 minutes of a possible 24780 or 62%
Astronomical total minutes: 15940 minutes of a possible 25709 or 62%
Today’s Observations:
7 A.M.
Weather: Vertical visibility 300 feet, sky obscured
Temperature: 71F; Dew Point: 71F; Relative Humidity: 100%
Wind: S at 7 kts
Sea-level pressure: 30.29 ins. Hg: rising unsteadily
Visibility: 1/8 mile, fog
6-hr Max temp: 71F
6-hr Min temp: 70F
24-hr Precip: 0.00 ins.
BHO SA 1155 W3 X 1/8F 257/71/71/1907/029/ 8/// 52002 10071 20070
10 A.M.
Weather: Overcast Stratus
Temperature: 76F; Dew Point: 73F; Relative Humidity: 92%
Wind: SSW at 7 kts
Sea-level pressure: 30.28 ins. Hg: rising, then falling
Visibility: 25 miles (distant fog)
3-hr Precip: Trace
BHO SA 1455 E11 OVC 25 254/76/73/2107/028/ THN F ALQDS/ 8/6//
58003 6///
1 P.M.
Weather: Scattered Cumulus, Broken Altocumulus, Broken Cirrus
Temperature: 79F; Dew Point: 72F; Relative Humidity: 79%
Wind: SSW at 7 kts
Sea-level pressure: 30.22 ins. Hg: rising, then more rapidly
Visibility: 45 miles, hazy
6-hr Max temp: 80F
6-hr Min temp: 71F
6-hr Precip: Trace
BHO SA 1755 19 SCT E65 BKN E200 BKN 45 232/79/72/2007/022/
HAZY/ 8/231 58022 6/// 10080 20071
SUMMARY FOR WEDNESDAY, SEPTEMBER 9, 2020
TEMPERATURE (DEGREES F)
MAX…..80 NORMAL…..74
MIN…..62 NORMAL…..57
MEAN….71 NORMAL…..66
DEPARTURE FROM 30-YEAR NORMAL……………. +5
TOTAL DEPARTURE FOR THE MONTH……………. +20 [+2.0 DEGREES/DAY]
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY………… 6 DEPARTURE……+3
TOTAL COOLING UNITS FOR THE MONTH………… 38 DEPARTURE……+8
TOTAL COOLING UNITS FOR THE SEASON………..795 DEPARTURE….+228
TOTAL COOLING UNITS LAST SEASON TO DATE……634 DEPARTURE….+161
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..16 S AT 9:59 P.M.
AERO…………………….15 S AT 8:08 P.M.
ASOS…………………….16 S AT 8:25 P.M.
DAVIS……………………15 S AT 8:13 P.M.
RMY 16 MERLIN 15
FASTEST MILE FOR YESTERDAY………………….12 S AT 10:01 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….13 S AT 10:01 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………12 S AT 9:55 P.M.
AVERAGE WIND SPEED AND DIRECTION……………6.5 S
ASOS……………………7.3
DAVIS…………………..6.2 SSW [202 deg.]
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.01 DEPARTURE….-0.12
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….0.23 DEPARTURE….-0.86
ASOS…………..0.24
TOTAL PRECIPITATION FOR THE YEAR……….33.04 DEPARTURE….-3.07
ASOS………….33.82
PRELIMINARY CLIMATE SUMMARY FOR AUGUST 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
08/01 87/66/77/+5/0.00/866/100 18 S AERO 21 S RMY 19
08/02 85/69/77/+5/0.02/320/37 36 S AERO 37 S RMY 38
08/03 91/75/83/+11/0.00/715/83 36 WSW AERO 38 SW RMY 36
08/04 83/71/77/5/0.21/094/11 67 SSE AERO 71 S RMY 70
08/05 90/68/79/+7/0.00/668/78 28 SW AERO 30 SW RMY 29
08/06 84/65/75/3/0.00/701/82 20 W AERO 17 W RMY 19
08/07 79/65/72/0/T/136/16 16 NE AERO 16 NE RMY N/A
08/08 83/64/74/+2/0.00/612/72 20 S AERO 20 S RMY 19
08/09 90/65/78/+6/0.00/661/78 26 SSW AERO 26 SSW RMY 26
08/10 94/69/82/+11/0.00/727/86 22 W AERO 20 W RMY 20
08/11 92/72/82/+11/0.00/708/84 31 SSW AERO 35 SSW RMY 31 TSTM
08/12 93/74/84/+13/0.00/647/77 22 SSW AERO 22 SW RMY 19
08/13 88/71/80/+9/0.00/528/63 18 ENE AERO 18 NE RMY 18
08/14 82/67/75/+4/0.00/618/74 23 ENE AERO 23 ENE RMY N/A
08/15 67/62/65/-6/T/000/00 33 NNE AERO 32 NNE RMY N/A
08/16 69/62/66/-5/…./000/00 26 ENE AERO 28 ENE RMY 26
08/17 73/59/66/-5/…./339/41 25 NE AERO 24 NE RMY N/A
08/18 84/63/74/+3/…./784/95 23 W AERO 23 W RMY 24
08/19 81/59/70/0/0.03/526/64 26 W AERO 28 W RMY 27
08/20 80/56/68/-2/0.00/804/98 22 W AERO 21 W RMY 22
08/21 88/61/75/+5/0.00/719/88 28 SW AERO 26 SW RMY 28
08/22 85/66/76/+6/0.26/521/64 18 NNE AERO 16 S RMY 16
08/23 89/63/76/+6/2.21/552/68 60 WNW AERO 53 WNW RMY 58 TSTM HAIL
08/24 87/67/77/+7/0.00/493/61 18 S AERO 18 S RMY 19 TSTM
08/25 86/65/76/+7/0.01/492/61 35 NNW AERO 37 NNW RMY 35
08/26 74/56/65/-4/0.00/780/97 29 NW AERO 32 NW RMY N/A
08/27 68/57/63/-6/0.33/008/01 18 SSE AERO 20 SSE RMY 20 TSTM
08/28 80/59/70/+1/0.00/559/70 20 W AERO 20 W RMY N/A
08/29 74/65/70/+1/0.06/000/00 32 W AERO 32 W RMY N/A
08/30 75/57/66/-2/0.00/793/100 36 W AERO 36 W RMY N/A
08/31 75/54/65/-3/0.00/569/72 20 S AERO 20 S RMY 20
DAILY RECORDS FOR AUGUST 2020
8/23/20: DAILY RECORD HIGH MAXIMUM TEMPERATURE OF 89F,
BREAKS PREVIOUS RECORD of 88F SET IN 1918, 1947, 1949, 1996
8/23/20: DAILY RECORD PRECIPITATION OF 2.21 INS,
BREAKS PREVIOUS RECORD OF 2.09 INS SET IN 2010
8/23/20: DAILY RECORD PEAK WIND GUST OF 60 MPH,
TIES PREVIOUS RECORD OF 60 MPH SET IN 1940
PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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
09/01 76/59/68/0/0.00/…/.. 22 SSE AERO 21 SE RMY 20
09/02 69/59/64/-4/…/…/.. 23 SSE AERO 23 SSE RMY 24
09/03 75/66/71/+4/…/…/.. 22 SSW AERO 21 SSW RMY n/a
09/04 82/62/72/+5/0.00/…/.. 26 WNW AERO 26 WNW RMY 25
09/05 76/55/66/-1/0.00/…/.. 25 W AERO 25 W RMY 24
09/06 78/58/68/+1/0.00/…/.. 24 W AERO 24 W RMY N/A
09/07 79/61/70/+4/0.00/…/.. 27 SSE AERO 30 SSE RMY 28
09/08 82/61/72/+6/0.00/…/.. 17 S AERO 16 S RMY 17
09/09 80/62/71/+5/0.00/…/.. 16 S AERO 15 S RMY 16
09/10 The low since midnight is 69F, the daily normal low is 57F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
RECORDS FOR SEPTEMBER 10
HIGH 90F IN 1931,1989
LOW 41F IN 1956
PRECIP 5.60 INCHES IN 1999 (DAILY RECORD FOR SEPTEMBER)
PEAK GUST 48 MPH NW IN 1972
RECORDS FOR SEPTEMBER 11
HIGH 93F IN 1983, 2013
LOW 37F IN 1917
PRECIP 5.23 INCHES IN 1954 (HURRICANE EDNA)
PEAK GUST 101 MPH NW IN 1954 (HURRICANE EDNA)
TODAY’S REPORT PREPARED BY: Andrew Swanson
