Thursday, August 20, 2020

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

THURSDAY, AUGUST 20, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

A REAL STUNNING LATE SUMMER DAY ATOP GREAT BLUE HILL

Yesterday’s early evening showers quickly exited
the area setting up for a beautiful start to our
Thursday. We observed near perfect visibility and
clear skies right out of the gate. The rocky
summit of Mount Monadnock in southwestern New
Hampshire was in clear, breathtaking view. Visibility
and mostly clear skies held firm throughout all observation
periods. Interestingly, the last recorded 85 mile
or greater of visibility from our rooftop was
June 1st, 2020…a welcomed return! Coupled with the
excellent viewing distance and bountiful sunshine,
dew points are also a paralleling story. Dew points
began in the mid-50s crashing to the upper-40s by
early afternoon! A sampling of the fall season to come!

Winds have remained rather gentle topping out
so far at 20 MPH. The dominant direction has been
via the northwest.

The high so far today is 78F, 1 degree
below the daily normal maximum of 79F.
The low since midnight is 56F, 6 degrees
below the normal minimum of 62F.

Today’s Observations:

7 A.M.
Weather: Clear (few cirrus W-N)
Temperature: 61F; Dew Point: 53F; Relative Humidity: 75%
Wind: NNW at 11 kts
Sea-level pressure: 30.07 ins. Hg: rising, then more rapidly
Visibility: 85 miles
6-hr Max temp: 61F
6-hr Min temp: 56F
24-hr Precip: 0.03 ins.
BHO SA 1155 CLR 85 184/61/53/3311/007/ FEW CI DSNT W-N/
8/001 70003 53014 10061 20056

10 A.M.
Weather: Clear (few cumulus and few cirrus/cirrostratus
distant W-N)
Temperature: 73F; Dew Point: 48F; Relative Humidity: 41%
Wind: NNW at 7 kts
Sea-level pressure: 30.08 ins. Hg: rising, then falling
Visibility: 85 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 85 186/73/48/3307/008/ FEW CU DSNT W-N FEW CI/CS
DSNT W-N 8/101 50002

1 P.M.
Weather: Scattered Cumulus (few cirrus distant NW-NE)
Temperature: 77F; Dew Point: 47F; Relative Humidity: 34%
Wind: WNW at 9 kts
Sea-level pressure: 30.03 ins. Hg: falling unsteadily
Visibility: 85 miles
6-hr Max temp: 78F
6-hr Min temp: 61F
6-hr Precip: 0.00 ins.
BHO SA 1755 65 SCT 85 169/77/47/2909/003/ FEW CI DSNT NW-NE/
8/101 57013 10078 20061

SUMMARY FOR WEDNESDAY, AUGUST 19, 2020

TEMPERATURE (DEGREES F)
MAX…..81   NORMAL…..79
MIN…..59   NORMAL…..62
MEAN….70   NORMAL…..70

DEPARTURE FROM 30-YEAR NORMAL……………… 0
TOTAL DEPARTURE FOR THE MONTH……………..+79 [+4.0 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY………………5  DEPARTURE…….-1
TOTAL COOLING UNITS FOR THE MONTH…………….201  DEPARTURE……+74
TOTAL COOLING UNITS FOR THE SEASON……………688  DEPARTURE…..+210
TOTAL COOLING UNITS LAST SEASON TO DATE……….556  DEPARTURE…..+132

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..26 W   AT  5:41 P.M.
AERO…………………….28 W   AT  5:42 P.M.
ASOS…………………….29 W   AT  5:42 P.M.
DAVIS……………………27 WNW AT  5:46 P.M
RMY 27  MERLIN 26
FASTEST MILE FOR YESTERDAY………………….19 SSW AT  2:32 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….20 SSW AT  2:32 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………20 W   AT  5:42 P.M.
AVERAGE WIND SPEED AND DIRECTION……………7.0 WNW
ASOS……………………7.5
DAVIS…………………..7.4 WNW [289 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.03  DEPARTURE……-0.10
ASOS…………..0.03
TOTAL PRECIPITATION FOR THE MONTH……….0.87  DEPARTURE……-1.75
ASOS…………..0.89
TOTAL PRECIPITATION FOR THE YEAR……….29.94  DEPARTURE……-3.67
ASOS………….30.69

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/…/..             18 S    AERO 21 S    RMY 19
08/02  85/69/77/+5/0.02/…/..             36 S    AERO 37 S    RMY 38
08/03  91/75/83/+11/0.00/…/..            36 WSW  AERO 38 SW   RMY 36
08/04  83/71/77/5/0.21/…/..              67 SSE  AERO 71 S    RMY 70
08/05  90/68/79/+7/0.00/…/..             28 SW   AERO 30 SW   RMY 29
08/06  84/65/75/3/0.00/…/..   20 W    AERO 17 W    RMY 19
08/07  79/65/72/0/T/…/..                 16 NE   AERO 16 NE   RMY N/A
08/08  83/64/74/+2/0.00/…/..             20 S    AERO 20 S    RMY 19
08/09  90/65/78/+6/0.00/…/..             26 SSW  AERO 26 SSW  RMY 26
08/10  94/69/82/+11/0.00/…/..            22 W    AERO 20 W    RMY 20
08/11  92/72/82/+11/0.00/…/..            31 SSW  AERO 35 SSW  RMY 31  TSTM
08/12  93/74/84/+13/0.00/…/..            22 SSW  AERO 22 SW   RMY 19
08/13  88/71/80/+9/0.00/…/..             18 ENE  AERO 18 NE   RMY 18
08/14  82/67/75/+4/0.00/…/..             23 ENE  AERO 23 ENE RMY N/A
08/15  67/62/65/-6/T/…/..                33 NNE  AERO 32 NNE  RMY N/A
08/16  69/62/66/-5/…./…/..             26 ENE  AERO 28 ENE  RMY 26
08/17  73/59/66/-5/…./…/..             25 NE   AERO 24 NE   RMY N/A
08/18  84/63/74/+3/…./…/..             23 W    AERO 23 W    RMY 24
08/19  81/59/70/0/0.03/…/..              26 W    AERO 28 W    RMY 27

08/20 The low since midnight is 56F, the daily normal low is 62F

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

RECORDS FOR AUGUST 20
HIGH 93F IN 1937
LOW 48F IN 1896, 1905, 1949
PRECIP 2.71 INCHES IN 1970
PEAK GUST 47 MPH W IN 1983

RECORDS FOR AUGUST 21
HIGH 92F IN 1937, 1995
LOW 47F IN 1982
PRECIP 2.84 INCHES IN 1888
PEAK GUST 54 MPH WSW IN 2004

TODAY’S REPORT PREPARED BY: Andrew Swanson