Friday, July 17, 2020

| July 17, 2020 | Reply

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

FRIDAY, JULY 17, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

A COOL & DREARY FRIDAY ATOP GREAT BLUE HILL…

We arrived on the summit early this morning under
overcast skies and rather chilly temperatures. At
times, the summit was socked in low, passing clouds
making visibility extremely limited. A quick downpour
then rolled through the area just before the 7AM
observation and exited minutes after the observation
window! The storm produced 0.19 inches in total of
beneficial rainfall. Overcast skies persisted for
the remainder of the day with visibility fluctuating
between 15 to 30 miles thanks to thin distant fog.
Winds have remained generally light at around 9-12
MPH on average.

Today is yet again on the cooler side, reaching 67
degrees by 1 P.M. This is 14 degrees below the
daily normal high of 81F. The low since midnight
is 57F, which is 5 degrees below the daily normal
low of 63F.

PRELIMINARY STATS FOR JUNE 2020

TEMPERATURE, Deg. F
Avg. Max. 78.0 [+3.0]
Avg. Min. 59.1 [+2.0]
Mean      68.6 [+2.5]
24-hour corrected mean: 67.5
Max. for month: 90F on the 20th
Min. for month: 42F on the 1st

HEATING DEGREE DAYS
Total heating units:     40 [-33]
Total for the season:  5852 [-402]
Total for last season: 6254

COOLING DEGREE DAYS
Total cooling units:    152  [+47]
Total for the season:   184  [+55]
Total for last season:  89

PRECIPITATION, Inches
Total: 7.56 [+3.25]
Greatest in 24 hrs: 4.71 inches on the 28th-29th

WIND, mph
Avg. uncorrected wind speed: 9.1 mph
Avg. corrected wind speed:   9.8 mph
Prevailing wind direction:   S [15%]
Peak gust and direction:     55 SW on the 6th

SUNSHINE:
Campbell-Stokes card minutes: 15996 minutes of a possible 26376 or 61%
Astronomical total minutes: 16650 minutes of a possible 27422 or 61%

Today’s Observations:

7 A.M.
Weather: Sky partially obscured, overcast stratus fractus,
moderate rain
Temperature: 58F; Dew Point: 57F; Relative Humidity: 97%
Wind: SE at 7 kts
Sea-level pressure: 30.24 ins. Hg: rising, then falling
Visibility: 5 miles, fog (visibility 1 mile N to S)
6-hr Max temp: 59F
6-hr Min temp: 57F
3-hr Precip: 0.18 ins.
24-hr Precip: 0.18 ins.
BHO SA 1155 –X E1 OVC 5RF 240/58/57/1407/024/ STFRA OCCLY
DRFTG OVR SMT VSBY N-S 1 RB30/ 8/6// 50006 60018 70018
10059 20057

10 A.M.
Weather: Overcast Stratus Fractus
Temperature: 60F; Dew Point: 59F; Relative Humidity: 95%
Wind: SSE at 8 kts
Sea-level pressure: 30.19 ins. Hg: falling unsteadily
Visibility: 30 miles, thin fog
3-hr Precip: 0.01 ins.
BHO SA 1455 E15 OVC 30 222/60/59/1608/019/ HIR CLDS VSB
DSNT N-SE THN F ALQDS RE1205/ 8/6// 57018 60001

1 P.M.
Weather: Overcast Stratus
Temperature: 67F; Dew Point: 64F; Relative Humidity: 91%
Wind: S at 9G15 kts
Sea-level pressure: 30.14 ins. Hg: falling unsteadily
Visibility: 20 miles, thin fog
6-hr Max temp: 67F
6-hr Min temp: 58F
6-hr Precip: 0.01 ins.
BHO SA 1755 E13 OVC 20 205/67/64/1809G15/014/ THN F ALQDS/
8/6// 58017 60018 10067 20058

SUMMARY FOR THURSDAY, JULY 16, 2020

TEMPERATURE (DEGREES F)
MAX…..73   NORMAL…..81
MIN…..57   NORMAL…..63
MEAN….65   NORMAL…..72

DEPARTURE FROM 30-YEAR NORMAL…………….. -7
TOTAL DEPARTURE FOR THE MONTH……………..+12 [+0.6 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………….. 0  DEPARTURE…… -7
TOTAL COOLING UNITS FOR THE MONTH…………….115  DEPARTURE……. +8
TOTAL COOLING UNITS FOR THE SEASON……………299  DEPARTURE…….+63
TOTAL COOLING UNITS LAST SEASON TO DATE……….253  DEPARTURE…….+46

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..21 E   AT  3:29 P.M.
AERO…………………….21 E   AT  3:43 P.M.
ASOS…………………….20 ESE AT  5:36 P.M.
DAVIS……………………19 E   AT  3:29 P.M RMY 19
FASTEST MILE FOR YESTERDAY………………….13 ESE AT  5:22 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….15 ESE AT  5:21 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………15 ESE AT  5:21 P.M.
AVERAGE WIND SPEED AND DIRECTION………….. 7.3 ENE
ASOS………………….. 7.4
DAVIS…………………. 7.9 ESE [109 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.18  DEPARTURE……+0.04
ASOS…………..0.18
TOTAL PRECIPITATION FOR THE MONTH……….1.05  DEPARTURE……-0.88
ASOS…………..1.04
TOTAL PRECIPITATION FOR THE YEAR……….28.40  DEPARTURE……-0.50
ASOS………….29.05

PRELIMINARY CLIMATE SUMMARY FOR JUNE 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

06/01  64/42/53/-9/T/0.0/724/80            28 WNW  AERO 29 WNW RMY 28
06/02  72/45/59/-3/0.01/0.0/689/76         28 W    AERO 27 W   RMY 28
06/03  79/55/67/+5/0.00/0.0/400/44         29 W    AERO 28 W   RMY 26
06/04  87/62/75/+12/0.00/0.0/673/74        26 W    AERO 25 S   RMY N/A
06/05  80/65/73/+10/0.14/0.0/300/33        28 SSW  AERO 28 SSW RMY N/A TSTM
06/06  86/57/72/+9/1.14/0.0/301/33         55 SW   AERO 59 SW  RMY 59  TSTM
06/07  68/54/61/-3/0.00/0.0/255/28         24 NW   AERO 24 NW  RMY N/A
06/08  77/51/64/0/0.00/0.0/866/95          25 W    AERO 24 W   RMY 25
06/09  77/60/69/+5/T/0.0/110/12            23 E    AERO 21 E   RMY N/A
06/10  70/58/64/-1/0.00/0.0/658/72         25 E    AERO 24 E   RMY N/A
06/11  71/64/68/+3/0.62/0.0/165/18         40 S    AERO 40 S   RMY 42
06/12  82/63/73/+8/0.00/0.0/705/77         26 W    AERO 25 W   RMY 27
06/13  71/53/62/-3/0.00/0.0/669/73         21 WNW  AERO 20 WNW RMY N/A
06/14  67/49/58/-8/0.00/0.0/852/93         21 E    AERO 21 ENE RMY 21
06/15  67/53/60/-6/5/0.00/0.0/696/76       21 NE   AERO 16 ENE RMY 20
06/16  73/54/64/-2/0.00/0.0/889/97         18 E    AERO 18 E   RMY 18
06/17  78/57/68/+1/0.00/0.0/889/97         20 S    AERO 20 S   RMY 20
06/18  86/59/73/+6/0.00/0.0/715/78         22 S    AERO 22 SSW RMY 22
06/19  86/66/76/+9/0.00/0.0/789/86         22 S    AERO 22 S   RMY 21
06/20  90/65/78/+10/0.00/0.0/834/91        22 S    AERO 21 S   RMY 21
06/21  90/66/78/+10/0.83/0.0/514/56        33 ESE  AERO 35 ESE RMY 33  TSTM
06/22  77/65/71/+3/T/0.0/761/83            15 E    AERO 17 S   RMY 14
06/23  85/65/75/+7/0.00/0.0/431/47         27 S    AERO 24 S   RMY 26
06/24  84/66/75/+6/0.00/0.0/348/38         25 S    AERO 24 S   RMY 25
06/25  84/63/74/+5/0.00/0.0/806/88         29 W    AERO 29 W   RMY 29
06/26  83/65/74/+5/0.02/0.0/769/84         25 S    AERO 25 S   RMY 27
06/27  82/65/74/+5/0.05/0.0/330/36         21 S    AERO 20 S   RMY 20
06/28  84/62/73/+3/3.27/0.0/421/46         35 W    AERO 33 N   RMY 37  TSTM
06/29  71/61/66/-4/1.46/0.0/064/07         18 NE   AERO 18 NE  RMY 18  TSTM
06/30  68/62/65/-5/0.02/0.0/027/03         14 ENE  AERO 14 ENE RMY 13

Record rainfall on the 28th of 3.27″. Old record 2.09″ in 1938

PRELIMINARY CLIMATE SUMMARY FOR JULY 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

07/01  76/63/70/0/0.00/228/25              16 E    AERO 14 E   RMY 14  TSTM
07/02  86/61/74/4/0.00/803/88              30 WSW  AERO 25 WSW RMY 33
07/03  73/60/67/-4/0.00/091/10             30 NE   AERO 28 NE  RMY 30
07/04  79/60/70/-1/0.00/565/62             16 S    AERO 16 S   RMY 16
07/05  83/63/73/+2/0.54/373/41             24 NW   AERO 30 NW  RMY 26  TSTM
07/06  73/60/67/-4/0.00/…/..             20 ENE  AERO 16 NNE RMY 18
07/07  78/60/69/-2/0.00/…/..             25 S    AERO 25 S   RMY 26
07/08  83/64/74/+2/0.00/…/..             32 SSW  AERO 32 SSW RMY 32
07/09  89/70/80/+8/0.00/…/.              24 S    AERO 23 S   RMY 22
07/10  83/70/77/+5/0.05/…/..             30 SSE  AERO 32 SSE RMY N/A
07/11  85/70/78/+6/0.00/…/..             39 S    AERO 39 S   RMY 38
07/12  86/70/78/+6/0.00/…/..             28 WSW  AERO 28 WSW RMY 29
07/13  82/69/76/+4/0.23/…/..             30 SSE  AERO 31 SSE RMY 30  TSTM
07/14  78/63/71/-1/0.00/…/..             26 ENE  AERO 25 ENE RMY 26
07/15  72/59/66/-6/0.00/…/..             21 NE   AERO 21 NE  RMY N/A
07/16  73/57/65/-7/0.00/…/..             21 E    AERO 21 E   RMY 19

07/17 The low since midnight is 57F, the daily normal low is 63F

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):

RECORDS FOR JULY 17
HIGH 96F IN 1999
LOW 47F IN 1892
PRECIP 1.39 INS IN 1989
WIND 46 MPH WNW IN 1971

RECORDS FOR JULY 18
HIGH 96F IN 1991, 1999
LOW 54F IN 1892, 1956, 1971
PRECIP 1.65 INS IN 2000
WIND 43e MPH SW IN 1949

TODAY’S REPORT PREPARED BY: Andrew Swanson

Category: Daily Discussions

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