Thursday, September 19, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, SEPTEMBER 19, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

SPECTACULAR DAY WITH COOL TEMPERATURES, VERY
DRY AIR, AND EXCELLENT VISIBILITY…

We’re seeing yet another amazing day here at Blue
Hill with clear skies, pleasant temperatures, and
very dry air for this time of year. The dew point
has falling into the mid 30s this afternoon indicating
a very dry air mass over the region. With this dry air
comes excellent visibility which has been holding at
80 miles.

Not much wind to speak of today with our peak gust so
far only around 16 mph. Wind has been light and varible
today, but generally out of a northerly direction.

The high so far today has been 66F. This is 5 degrees
below the normal maximum of 71F. The low since midnight
is 43F, 11 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: Clear, few Cumulus distant NE-SE, thin smoke layer all quadrants
Temperature: 46F; Dew Point: 40F; Wind: N at 10 kts
Sea-level pressure: 30.37 ins. Hg, rising, then more rapidly
Visibility: 70 miles
6-hr Max temp: 49F
6-hr Min temp: 43F
24-hr Precip: 0.00 ins.
BHO SA 1155 CLR 70 283/46/40/3510/037/ FEW DSNT CU NE-SE THN K LYR ALQDS/
8/100 53013 10049 20043

10 A.M.
Weather: Clear, few Cumulus distant E-S
Temperature: 60F; Dew Point: 38F; Wind: NNE at 4 kts
Sea-level pressure: 30.37 ins. Hg, steady
Visibility: 80 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 80 285/60/38/0204/037/ FEW DSNT CU E-S WND L/V/ 8/100 50002

1 P.M.
Weather: Clear, few Stratocumulus distant E-ESE, few Cumulus distant S
Temperature: 65F; Dew Point: 36F; Wind: N at 3 kts
Sea-level pressure: 30.35 ins. Hg, steady, then falling
Visibility: 80 miles
6-hr Max temp: 66F
6-hr Min temp: 46F
6-hr Precip: 0.00 ins.
BHO SA 1755 CLR 80 276/65/36/0103/035/ FEW SC DSNT E-ESE FEW CU S WND L/V/
8/500 58009 10066 20046

SUMMARY FOR WEDNESDAY, SEPTEMBER 18, 2019

TEMPERATURE (DEGREES F)
MAX…..61   NORMAL…..71
MIN…..49   NORMAL…..54
MEAN….55   NORMAL…..62

DEPARTURE FROM 30-YEAR NORMAL………………….-7
TOTAL DEPARTURE FOR THE MONTH…………………-35 [-1.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON AUG TO JUL)
TOTAL HEATING UNITS FOR YESTERDAY…………..10   DEPARTURE………+6
TOTAL HEATING UNITS FOR THE MONTH…………..53   DEPARTURE……..+10
TOTAL HEATING UNITS FOR THE SEASON………….65   DEPARTURE………-3
TOTAL HEATING UNITS LAST SEASON TO DATE……..47   DEPARTURE……..+18

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE………-2
TOTAL COOLING UNITS FOR THE MONTH…………..25   DEPARTURE……..-23
TOTAL COOLING UNITS FOR THE SEASON…………644   DEPARTURE……..+59
TOTAL COOLING UNITS LAST SEASON TO DATE…….849   DEPARTURE…….-211

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..26 NE  AT  1:43 P.M.
AERO…………………….25 NE  AT  1:37 P.M.
ASOS…………………….26 NE  AT  1:36 P.M.
DAVIS……………………25 NE  AT  8:03 A.M. RMY 25
FASTEST MILE FOR YESTERDAY………………….16 NE  AT 10:42 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….18 NNE AT  1:43 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………18 ENE AT 10:57 A.M.
AVERAGE WIND SPEED AND DIRECTION……………10.7 NE
ASOS……………………10.4
DAVIS…………………..11.0 NE [51 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……-1.32
ASOS…………..0.96
TOTAL PRECIPITATION FOR THE YEAR……….38.13  DEPARTURE……+0.80
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  61/49/55/-7/0.00/…/..                26 NE  AERO 25 NE  RMY 25

9/19  The low since midnight is 43F, 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 19
HIGH 87F IN 1906,1983
LOW 37F IN 1929
PRECIP 3.69 INCHES IN 1936
PEAK GUST 55 MPH S IN 2012

RECORDS FOR SEPTEMBER 20
HIGH 90 IN 1983
LOW 34 IN 1979
PRECIP 4.57 INS IN 1899
PEAK GUST 44 MPH NE IN 1972

TODAY’S REPORT PREPARED BY: Matt Douglas