Tuesday, July 20, 2021

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

TUESDAY, JULY 20, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0425E
SUNSET:  1915E

INCREASING SMOKE ALOFT AND INCREASING HAZE AT THE SURFACE….

So we finally ditch the clouds and rain, but despite
clear skies this morning, a smoke layer aloft has dimmed
the sun all day. This smoke is the result of wildfires
out in western United States and Canada.

In addition to the smoke aloft, haze has been increasing
at the surface as well reducing visibility from 25 miles
this morning to only 6 miles this afternoon! Personally
I haven’t seen an obstruction to visibility of this level
from haze since the 1990s!

It’s another humid day as well with dew points hanging out
in the upper 60s all day. With light winds, it feels a bit
stifling out there.

We are still on the watch for breaking the record for
wettest July on record. We are currently 1.15″ away from
tying the record from 1938. With thunderstorms in the
forecast potentially this evening and more so tomorrow,
we have a shot to do it by Thursday morning. Stay tuned!

Here are the rankings for wettest Julys as compiled by our
Chief Scientist, Mike Iacono…

BHO Wettest Julys, inches (1885-2021)

1) 11.67 in 1938
2) 10.68 in 1988
3) 10.43 in 1921
4) 9.52 in 1915
5) 8.47 in 1889
6) 7.62 in 2009
7) 7.55 in 1916

The high so far today is 83F, 1 degree above the daily
normal maximum of 82F. The low so far today is 64F, which is
equal to the daily normal minimum of 64F.

On a side note, the renovations have now begun in earnest.
We are no longer operating out of the tower and have moved to
another part of the building. All wind instruments on the main
tower have been taken offline and will remain so until further
notice. Please be patient with us as we navigate through our
new routine. Data at times may be delayed.

———————————————–

Today’s Observations:

7 A.M.
Weather: Clear, smoke layer aloft, sun dimmed
Temperature: 68F; Dew Point: 66F; Relative Humidity: 93%
Wind: W @ 5 kts, wind light
Sea-level pressure: 29.91 in. Hg; rising unsteadily
Visibility: 25 miles, thin fog
6-hr Max temp: 68F
6-hr Min temp: 64F
24-hr Precip: 0.06 in.
BHO SA 1155 CLR 25 128/68/66/2705/991/ THN F ALQDS K LYR ALF
SUN DIMMED WND LGT/ 8/000 52006 70006 10068 20064

10 A.M.
Weather: Clear, smoke layer aloft, sun dimmed
Temperature: 77F; Dew Point: 69F; Relative Humidity: 77%
Wind: WNW @ 4 kts, wind light
Sea-level pressure: 29.92 in Hg; rising, then more slowly
Visibility: 10 miles, hazy
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 10 131/77/69/3004/992/ K LYR ALF SUN DIMMED
HAZY WND LGT/ 8/000 51003

1 P.M.
Weather: Scattered cumulus, smoke layer aloft, sun dimmed
Temperature: 80F, Dew point: 68F; Relative Humidity: 68%
Wind: W @ 6 kts  
Sea-level pressure: 29.89 in Hg; falling, then more rapidly
Visibility: 6 miles, haze
6-hr Max temp: 83F
6-hr Min temp: 68F
6-hr Precip: 0.00 ins.
BHO SA 1755 37 SCT 6H 122/80/68/2806/989/ K LYR ALF SUN DIMMED/
8/200 58009 10083 20068

SUMMARY FOR MONDAY, JULY 19, 2021

TEMPERATURE (DEGREES F)
MAX…….71     NORMAL…..82
MIN…….63     NORMAL…..64
MEAN……67     NORMAL…..73

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……….-6
TOTAL DEPARTURE FOR THE MONTH…………………-79 [-4.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2021 THRU JUN 2022)
TOTAL HEATING UNITS FOR YESTERDAY…………….0  DEPARTURE………0
TOTAL HEATING UNITS FOR THE MONTH……………26  DEPARTURE…….+21
TOTAL HEATING UNITS FOR THE SEASON…………..26  DEPARTURE…….+21
TOTAL HEATING UNITS LAST SEASON TO DATE……….1  DEPARTURE…….+25

COOLING DEGREE DAYS (SEASON: JAN 2021 THRU DEC 2021)
TOTAL COOLING UNITS FOR YESTERDAY…………….2  DEPARTURE……..-7
TOTAL COOLING UNITS FOR THE MONTH……………89  DEPARTURE…….-58
TOTAL COOLING UNITS FOR THE SEASON………….315  DEPARTURE…….+29
TOTAL COOLING UNITS LAST SEASON TO DATE……..328  DEPARTURE…….-13

PEAK WIND GUST (MPH):
                     Official……………….17 ENE @ 12:12 A.M.
                     AEROVANE (south tower)…..17 ENE @ 12:15 A.M.
                     VECTOR #2 (south tower)….18     @ 12:12 A.M.
                     DAVIS #2 (south tower)…..17 E   @ 12:19 A.M.
                     ASOS………..OUT OF SERVICE D/T RENOVATIONS
                     VECTOR #1……OUT OF SERVICE D/T RENOVATIONS
                     DAVIS #1…….OUT OF SERVICE D/T RENOVATIONS
                     RMY…………OUT OF SERVICE D/T RENOVATIONS  
                     MERLIN………OUT OF SERVICE D/T RENOVATIONS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………14 ENE @ 12:23 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..14     @ 12:18 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………14 E   @ 12:19 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE…….OUT OF SERVICE D/T RENOVATIONS
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE…OUT OF SERVICE D/T RENOVATIONS
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE..OUT OF SERVICE D/T RENOVATIONS
MAXIMUM 2-MINUTE RMY AVERAGE……..OUT OF SERVICE D/T RENOVATIONS

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL…… 5.3 NE [127 total miles]                     VECTOR #2……………. 6.3
                     DAVIS #2…………….. 5.8 NE
                     RMY……………..OUT OF SERVICE D/T RENOVATIONS
                     ASOS…………….OUT OF SERVICE D/T RENOVATIONS
                     VECTOR #1………..OUT OF SERVICE D/T RENOVATIONS
                     DAVIS #1…………OUT OF SERVICE D/T RENOVATIONS   

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.06  DEPARTURE….-0.05
TOTAL PRECIPITATION FOR THE MONTH…………10.52  DEPARTURE….+8.41
TOTAL PRECIPITATION FOR THE YEAR………….33.90  DEPARTURE….+4.82

 

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   80/65/73/+2/0.74/155/17           22 W   AERO 20 WSW  RMY 21
07/02   65/55/60/-11/1.49/000/00          37 NE  AERO 36 NE   RMY 39
07/03   56/54/55/-17/1.98/000/00          41 NE  AERO 44 NE   RMY 45 TSTM
07/04   66/54/60/-12/0.16/191/21          26 ENE AERO 23 ENE  RMY 26
07/05   74/53/64/-8/0.01/546/60           26 SSW AERO 28 SSW  RMY 27
07/06   87/66/77/+5/0.26/255/28           37 W   AERO 48 W    RMY 38 TSTM
07/07   88/88/77/+5/0.77/699/77           63 NW  AERO 75 NW   RMY 70 TSTM
07/08   67/59/63/-9/0.38/109/12           46 W   AERO 46 W    RMY 51 TSTM
07/09   73/62/68/-5/3.02/163/18           40 WNW AERO 44 WNW  RMY 43
07/10   71/63/67/-6/0.07/109/12           23 NE  AERO 21 NNE  RMY 22
07/11   81/61/71/-2/T/325/36              21 SW  AERO 19 S    RMY N/A
07/12   67/61/64/-9/1.01/000/00           31 ENE AERO 31 ENE  RMY N/A
07/13   66/60/63/-10/0.02/000/00          19 E   AERO 18 E    RMY N/A
07/14   80/62/71/-2/0.01/…/..           19 S   AERO 18 S    RMY N/A
07/15   88/67/78/+5/0.00/…/..           19 WSW AERO 18 SSW  RMY N/A
07/16   90/70/80/+7/0.04/…/..           36 NNW AERO 39 NNW  RMY N/A TSTM
07/17   78/64/71/-2/0.34/…/..           26 ENE AERO 25 ENE  RMY N/A TSTM
07/18   74/63/69/-4/0.15/…/..           22 NE  AERO 22 NE   RMY N/A TSTM
07/19   71/63/67/-6/0.07/…/..           17 ENE AERO 17 ENE  RMY N/A

07/20   The low since midnight is 64F, the daily normal low is 64F

RECORDS FOR JULY:
JULY 2: Record daily precipitation of 1.49″,
        Surpasses previous record of 1.42″ set in 1986

JULY 3: Record daily precipitation of 1.98″,
        Surpasses previous record of 1.36″ set in 1985

JULY 7: Record peak gust of 63 MPH,
        Surpasses previous record of 55 MPH set in 1989

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

RECORDS FOR JULY 20
HIGH 99F IN 1991
LOW 47F IN 1890
PRECIP 1.64 INS IN 1938
WIND 56e MPH SSW IN 1943

RECORDS FOR JULY 21
HIGH 100F IN 1977 [RECORD FOR MONTH]LOW 48F IN 1890
PRECIP 2.09 INS IN 1938
PEAK GUST 60e MPH WNW IN 1977

TODAY’S REPORT PREPARED BY: Matt Douglas