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

FRIDAY, JULY 23, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0428E
SUNSET:  1913E

A PLEASANT DAY WITH A MIX OF SUN AND CLOUDS....

While the visibility has hung around a measly 40 miles
throughout the day, the weather above our heads is a
better story. An abundance of sunshine is coinciding with
dew points in the upper-50s making it feel like a stellar
day - seems like these have been hard to come by this July!

We observed some morning altocumulus castellanus (ACC). ACC
indicate instability in the middle levels of the troposphere
(lowest layer of the atmosphere) which often lead to developing
convection. As such, we are noting distant thunderstorms to our
northwest moving southeast towards BHO.

A wind shift in the early afternoon from northwesterly to
onshore has brought a slight dip in the mercury after
topping out at 79F. 1PM temp was 76F.

The high so far today is 79F, 3 degrees below the daily
normal maximum of 82F. The low so far today is 62F, which is
2 degrees above the daily normal minimum of 64F.

-----------------------------------------------

Today's Observations:

7 A.M.
Weather: Scattered Altocumulus & Altocumulus Castellanus
Temperature: 67F; Dew Point: 59F; Relative Humidity: 75%
Wind: NNW @ 8 kts
Sea-level pressure: 30.11 in. Hg; rising, then rising more slowly
Visibility: 30 miles, hazy
6-hr Max temp: 67F
6-hr Min temp: 62F
24-hr Precip: TRACE
BHO SA 1155 130 SCT 30 196/67/59/3308/011/ HAZY/ 8/080/ 51013
10067 20062

10 A.M.
Weather: Clear, few cumulus E-WNW, few altocumulus SW
Temperature: 72F; Dew Point: 57F; Relative Humidity: 59%
Wind: N @ 8G12 kts
Sea-level pressure: 30.03 in Hg; rising unsteadily
Visibility: 60 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 60 171/72/57/3608G12/003/ FEW CU E-WNW FEW
AC SW/ 8/180 52004


1 P.M.
Weather: Broken Cumulus (few moderate cumulus E-N, few
cumulonimbus distant W to N moving SE)
Temperature: 79F, Dew point: 59F; Relative Humidity: 56%
Wind: ENE @ 10 kts  
Sea-level pressure: 30.09 in Hg; Falling, then falling more rapidly
Visibility: 45 miles, hazy
6-hr Max temp: 79F
6-hr Min temp: 67F
6-hr Precip: 0.00 ins.
BHO SA 1755 E60 BKN 45 190/79/59/65010/009/ FEW MDT CU E-N
FEW CB DSNT W-N MVG SE HAZY/ 8/300 58008 10079 20067


SUMMARY FOR THURSDAY, JULY 22, 2021

TEMPERATURE (DEGREES F)
MAX.......79     NORMAL.....82
MIN.......58     NORMAL.....64
MEAN......69     NORMAL.....73

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL..........-4
TOTAL DEPARTURE FOR THE MONTH.....................-84 [-4.0 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................4  DEPARTURE........-5
TOTAL COOLING UNITS FOR THE MONTH..............108  DEPARTURE.......-65
TOTAL COOLING UNITS FOR THE SEASON.............334  DEPARTURE.......+22
TOTAL COOLING UNITS LAST SEASON TO DATE........357  DEPARTURE.......-23

PEAK WIND GUST (MPH):
                     Official...................20 WNW @  1:04 P.M.
                     AEROVANE (south tower).....20 WNW @  1:04 P.M.
                     VECTOR #2 (south tower)....21     @  1:07 A.M.
                     DAVIS #2 (south tower).....18 N   @  1:07 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..................12 NW  @ 12:17 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE..............14     @  1:16 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE...............14 WNW @  1:16 P.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...... 6.9 NW [165 total miles]
                     VECTOR #2................ 7.6
                     DAVIS #2................. 7.2 WNW
                     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......TRACE  DEPARTURE....-0.11
TOTAL PRECIPITATION FOR THE MONTH............10.68  DEPARTURE....+8.24
TOTAL PRECIPITATION FOR THE YEAR.............34.06  DEPARTURE....+4.65


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   83/64/74/+1/0.00/.../..           23 NW  AERO 23 NW   RMY N/A
07/21   79/62/71/-2/..../.../..           26 NNW AERO 23 NNW  RMY N/A TSTM
07/22   79/58/69/-4/..../.../..           20 WNW AERO 20 WNW  RMY N/A TSTM

07/23 The low since midnight is 62, 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 23
HIGH 99F IN 1952
LOW 51F IN 1923,1977
PRECIP 1.82 INS IN 1953
PEAK GUST 54e MPH S IN 1946

RECORDS FOR JULY 24
HIGH 96F IN 1987
LOW 49F IN 1893,1912
PRECIP 2.27 INS IN 2008
PEAK GUST 46 MPH NE IN 2009

TODAY'S REPORT PREPARED BY: Andrew Swanson