Wednesday, September 18, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, SEPTEMBER 18, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

A FAIR AND COOL WEATHER DAY WITH GOOD VISIBILITY
AND A NORTHEASTERLY BREEZE….

Today’s visibility was 75 miles on average, with
dew points in the low 40’s. Skies were partly
cloudy, and a sea breeze was blowing in from the
northeast for the majority of the day. It is
beginning to feel a lot like fall atop Great Blue
Hill, with a high so far today of only 61F. This is
10 degrees below the normal maximum of 71F. The low
since midnight is 52F, 2 degrees below the normal of
54F.

PRELIMINARY STATS FOR AUGUST 2019

TEMPERATURE, Deg. F
Avg. Max. 80.4 [+1.2] Avg. Min. 62.1 [+0.3] Mean      71.3 [+0.8] 24-hour corrected mean: 70.5
Max. for month: 92F on the 19th
Min. for month: 51F on the 26th

COOLING DEGREE DAYS
Total cooling units:   211 [+22] Total for the season:  619 [+82] Total for last season: 753

PRECIPITATION, Inches
Total: 1.83 [-2.21] Greatest in 24 hrs: 0.81 ins. on the 28th-29th

WIND, mph
Avg. uncorrected wind speed: 9.1 mph
Avg. corrected wind speed:   9.8 mph
Prevailing wind direction: N/A
Peak gust and direction: N/A

SUNSHINE:
Campbell-Stokes card minutes: 16404 minutes of possible 24780 or 66%
Astronomical total minutes: 17074 minutes of possible 25768 or 66%

Today’s Observations:

7 A.M.
Weather: Scattered cumulus and altocumulus
Temperature: 53F; Dew Point: 45F; Wind: NNE at 9 kts, gusting to 16 kts
Sea-level pressure: 30.27 ins. Hg, rising steadily
Visibility: 70 miles
6-hr Max temp: 57F
6-hr Min temp: 52F
24-hr Precip: 0.00 ins.
BHO SA 1155 45 SCT 65 SCT 70 252/53/45/0209G16/027/ 8/180 53016
10057 20052

10 A.M.
Weather: Scattered cumulus, broken altocumulus
Temperature: 58F; Dew Point: 40F; Wind: NE at 14 kts, gusting to 21 kts
Sea-level pressure: 30.30 ins. Hg, steady, then rising
Visibility: 75 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 40 SCT E65 BKN 75 260/58/40/0514G21/030/ 8/180 51008

1 P.M.
Weather: Broken cumulus
Temperature: 60F; Dew Point: 40F; Wind: NNE at 11 kts, gusting to 22 kts
Sea-level pressure: 30.31 ins. Hg, steady, then rising
Visibility: 75 miles
6-hr Max temp: 61F
6-hr Min temp: 53F
6-hr Precip: 0.00 ins.
BHO SA 1755 E40 BKN 75 264/60/40/0211G22/031/ 8/100 53004 10061 20053

SUMMARY FOR TUESDAY, SEPTEMBER 17, 2019

TEMPERATURE (DEGREES F)
MAX…..67   NORMAL…..71
MIN…..49   NORMAL…..54
MEAN….58   NORMAL…..63

DEPARTURE FROM 30-YEAR NORMAL………………….-5
TOTAL DEPARTURE FOR THE MONTH…………………-28 [-1.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON AUG TO JUL)
TOTAL HEATING UNITS FOR YESTERDAY……………7   DEPARTURE………+3
TOTAL HEATING UNITS FOR THE MONTH…………..43   DEPARTURE………+1
TOTAL HEATING UNITS FOR THE SEASON………….55   DEPARTURE……..-12
TOTAL HEATING UNITS LAST SEASON TO DATE……..37   DEPARTURE……..+20

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE………-1
TOTAL COOLING UNITS FOR THE MONTH…………..25   DEPARTURE……..-21
TOTAL COOLING UNITS FOR THE SEASON…………644   DEPARTURE……..+61
TOTAL COOLING UNITS LAST SEASON TO DATE…….849   DEPARTURE…….-205

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..23 NW  AT  6:22 A.M.
AERO…………………….23 N   AT  9:28 A.M.
ASOS…………………….23 NW  AT  6:21 A.M.
DAVIS……………………22 NW  AT  6:19 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….16 ENE AT 12:54 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….16 ENE AT  1:29 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………17 E   AT  1:28 P.M.
AVERAGE WIND SPEED AND DIRECTION…………… 9.5 E
ASOS……………………10.0
DAVIS…………………..10.1 NNE [22 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.14
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….0.98  DEPARTURE……-1.18
ASOS…………..0.96
TOTAL PRECIPITATION FOR THE YEAR……….38.13  DEPARTURE……+0.94
ASOS………….37.99

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

9/01  73/56/65/-3/0.00/…/..                21 ENE AERO 14 ENE RMY 18
9/02  75/57/66/-2/0.37/…/..                39 W   AERO 41 W   RMY 41
9/03  77/61/69/+2/0.00/…/..                18 S   AERO 16 S   RMY N/A
9/04  83/61/72/+5/0.00/…/..                30 SW  AERO 28 SW  RMY 30
9/05  68/54/61/-6/0.00/…/..                23 NW  AERO 17 NW  RMY N/A
9/06  65/56/61/-6/…./…/..                37 ENE AERO 36 ENE RMY 36
9/07  70/51/61/-5/0.00/…/..                37 N   AERO 37 N   RMY N/A
9/08  73/53/63/-3/0.00/…/..                25 W   AERO 21 W   RMY N/A
9/09  71/54/63/-3/0.00/…/..                17 SE  AERO 16 SE  RMY 16
9/10  73/57/65/0/0.00/…/..                 25 S   AERO 25 S   RMY N/A
9/11  83/63/73/+8/0.00/…/..                31 SW  AERO 32 SW  RMY N/A
9/12  70/52/61/-4/0.11/…/..                29 ENE AERO 28 ENE RMY 28
9/13  65/49/57/-7/0.00/…/..                29 ENE AERO 27 ENE RMY 27
9/14  69/49/59/-5/…./…/..                36 S   AERO 37 S   RMY 37
9/15  78/62/70/+6/0.00/…/..                24 W   AERO 23 W   RMY 22
9/16  72/54/63/0/0.00/…/..                 25 WNW AERO 23 WNW RMY 25
9/17  67/49/58/-5/0.00/…/..                23 NW  AERO 23 N   RMY N/A

9/18  The low since midnight is 52F, normal daily minimum is 54F

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

RECORDS FOR SEPTEMBER 18
HIGH 88F IN 1906
LOW 36F IN 1919
PRECIP 4.25 INCHES IN 1996
PEAK GUST 77e MPH WNW IN 1948

RECORDS FOR SEPTEMBER 19
HIGH 87F IN 1906,1983
LOW 37F IN 1929
PRECIP 3.69 INCHES IN 1936
PEAK GUST 55 MPH S IN 2012

TODAY’S REPORT PREPARED BY: Benjamin Turner