Thursday, September 21, 2023

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

THURSDAY, SEPTEMBER 21, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0530E
SUNSET:  1744E

CONTINUED SUNSHINE ON GREAT BLUE HILL WITH LOWER WINDS…
TODAY IS THE 85TH ANNIVERSARY OF THE GREAT NEW ENGLAND
HURRICANE OF 1938…

Today has been a near picture perfect day on the hill, with plenty
of sunshine, seasonable temperatures, and comfortable conditions
overall. Clear skies remained for most of the day with the exception
of some cumulus that popped up during the afternoon hours. It has
been an ideal day for any outdoor activities.

Temperatures have been similar to yesterday with a high just topping
70F by the last observation. Dew points have remained in the low 50’s
which have provided some comfortable weather for the area.

The wind has been light today, with an average of only about 8 mph
so far, starting from the NNW this morning and gradually shifting more
NE by the afternoon. The peak gust so far occurred around 4am at about
17 mph.

Visibility started at 70 miles this morning and stayed within the 60
to 70 mile range for most of the day. Cooler temperatures, clear skies,
and a seasonable dew point all helped in providing us a great view today.

The maximum temperature so far today has been 71F, which is equal to the
normal high. The minimum temperature since midnight is 52F, which is 2
degrees below the normal low of 54F.

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Today’s Observations:

7 A.M.
Weather: Clear
Temperature: 54F; Dew Point: 49F; Relative Humidity: 85%
Wind: NNW @ 6 kts, wind light
Sea-level pressure: 1024.9 mb; 30.27 in. Hg: rising, then more
slowly
Visibility: 70 miles
6-hr Max temp: 54F
6-hr Min temp: 52F
24-hr Precip: 0.00 inches
BHO SA 1155 CLR 70 249/54/49/3306/027/ CLR WND LGT/ 8/000 51021
10054 20052

10 A.M.
Weather: Clear, few cumulus SE-S-SSW
Temperature: 65F; Dew Point: 52F; Relative Humidity: 62%
Wind: Calm
Sea-level pressure: 1025.7 mb; 30.29 in. Hg: rising then more
slowly
Visibility: 60 miles
3-hr Precip: 0.00 inches
BHO SA 1455 CLR 60 257/65/52/0000/029/ CLR FEW CU SE-S-SSW
WND CALM/ 8/100 51008

1 P.M.
Weather: Clear, few cumulus ESE-SW-N
Temperature: 71F; Dew Point: 52F; Relative Humidity: 52%
Wind: E @ 4 kts, wind light
Sea-level pressure: 1025.2 mb; 30.27 in. Hg: steady, then falling
Visibility: 60 miles
6-hr Max temp: 71F
6-hr Min temp: 54F
6-hr Precip: 0.00 inches
BHO SA 1755 CLR 60 252/70/52/0904/027/ FEW CU ESE-SW-N WND LGT/
8/200 58005 10071 20054

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SUMMARY FOR WEDNESDAY, SEPTEMBER 20, 2023

TEMPERATURE (DEGREES F)
MAX…….72   NORMAL…..71
MIN…….53   NORMAL…..54
MEAN……63   NORMAL…..63

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………..0
TOTAL DEPARTURE FOR THE MONTH…………………+80 [+3.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY…………….2  DEPARTURE……..-2
TOTAL HEATING UNITS FOR THE MONTH……………18  DEPARTURE…….-25
TOTAL HEATING UNITS FOR THE SEASON…………..19  DEPARTURE…….-42
TOTAL HEATING UNITS LAST SEASON TO DATE………32  DEPARTURE…….-13

COOLING DEGREE DAYS (SEASON: JAN 2023 THRU DEC 2023)
TOTAL COOLING UNITS FOR YESTERDAY…………….0  DEPARTURE……..-2
TOTAL COOLING UNITS FOR THE MONTH…………..119  DEPARTURE…….+56
TOTAL COOLING UNITS FOR THE SEASON………….689  DEPARTURE…….+30
TOTAL COOLING UNITS LAST SEASON TO DATE……..884  DEPARTURE……-195

PEAK WIND GUST (MPH):
Note: Instruments designated #1 = Main Tower, #2 = South Tower,
F420C, Contacting, Merlin, and Richards are all Main Tower.
E=Estimated

F420C (Official)……….E21 WNW  @  12:30 A.M.
VECTOR #1 (1-Sec)……….21 WNW  @  12:23 A.M.
VECTOR #2 (1-Sec)……….24 WNW  @  12:34 A.M.
DAVIS #1……………….23 W    @  12:47 A.M.
DAVIS #2 ………………22 WNW  @  12:34 A.M.
RMY #1 (Instantaneous)…..22 WNW  @  12:29 A.M.
RMY #2 (Instantaneous)…..24 WNW  @  12:34 A.M.
MERLIN…………………18 NW
RICHARDS (C5C) (Inst)……21      @  12:48 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………17 WNW  @  12:47 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..16      @  12:40 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..17      @  12:35 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………17 W    @  12:38 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………16 WNW  @  12:35 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 W    @  12:28 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..17 WNW  @  12:35 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………16      @  12:47 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………9.5 WNW [227 total miles] VECTOR #1……………….9.6
VECTOR #2………………10.3
DAVIS #1……………….10.0 WNW
DAVIS #2………………..9.8 NW
RMY #1………………….9.2 WNW
RMY #2…………………10.0 WNW
RICHARDS (C5C)………….10.0

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.15
TOTAL PRECIPITATION FOR THE MONTH…………..5.07 DEPARTURE…..+2.51
TOTAL PRECIPITATION FOR THE YEAR…………..45.52 DEPARTURE…..+8.35

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PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN)/SUN(%)/PEAK GUST/VEC1/RMY GUST
PEAK GUST: F420C (Official)
VEC1: Vector #1 1-second gust
RMY:  R.M. Young #1 wind gust recording system (Instantaneous)
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

9/1   73/52/63/-6/0.00/774/98             23 SSW VEC1 22 SSW RMY 21
9/2   79/56/68/-1/0.00/708/90             25 SW  VEC1 24 SW  RMY 26
9/3   85/61/73/+5/T/674/86                21 SW  VEC1 21 SW  RMY 21
9/4   85/68/77/+9/0.00/719/92             17 NW  VEC1 16 NW  RMY 16
9/5   86/68/77/+9/0.00/647/83             16 NNE VEC1 16 ENE RMY 16
9/6   89/70/80/+12/0.00/722/93            17 WSW VEC1 17 SSW RMY 18
9/7   92/72/82/+15/0.00/726/94            20 SSW VEC1 21 SSW RMY 21
9/8   86/70/78/+11/0.00/293/38            30 SSW VEC1 31 SSW RMY 32 TSTM
9/9   86/68/77/+10/0.49/291/38            30 S   VEC1 31 S   RMY 29 TSTM
9/10  78/67/73/+7/0.25/008/01             17 NE  VEC1 17 NE  RMY 15 TSTM
9/11  74/67/71/+5/0.64/023/03             15 E   VEC1 15 E   RMY 14 TSTM
9/12  79/65/72/+6/T/250/33                18 E   VEC1 17 E   RMY 18
9/13  76/64/70/+5/1.92/242/32             35 SSW VEC1 35 SSW RMY 36 TSTM
9/14  75/57/66/+1/0.00/670/89             24 NW  VEC1 24 NW  RMY 24
9/15  66/53/60/-5/0.00/465/62             36 N   VEC1 35 N   RMY 35
9/16  68/54/61/-3/0.21/022/03             44 WNW VEC1 44 WNW RMY 47
9/17  76/53/65/+1/0.00/685/92             26 WNW VEC1 25 WNW RMY 24
9/18  64/60/62/-1/1.56/000/00             33 WNW VEC1 33 WNW RMY 35 TSTM
9/19  70/56/63/0/0.00/…/..              35 WNW VEC1 37 WNW RMY 36
9/20  72/53/63/0/0.00/…/..              21 WNW VEC1 21 WNW RMY 22

9/21 The low since midnight is 52F, the daily normal low is 54F
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SEPTEMBER DAILY RECORDS

09/07/2023: NEW RECORD HIGH DAILY MINIMUM TEMPERATURE OF 72F;
BEATS THE RECORD OF 70F SET IN 1999

09/07/2023: RECORD HIGH TEMPERATURE OF 92F;
TIES THE RECORD OF 92F SET IN 2007 AND 2015

09/08/2023: RECORD HIGH DAILY MINIMUM TEMPERATURE OF 70F;
TIES THE RECORD OF 70F SET IN 2015

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

RECORDS FOR SEPTEMBER 21
HIGH 91 IN 1895
LOW 35 IN 1929, 1956, 1962
PRECIP 5.58 INS IN 1961 (HURRICANE ESTHER; RETURNED AS TS SEPT 25-26TH)
PEAK GUST 186 MPH S IN 1938 (GREAT NEW ENGLAND HURRICANE; CALCULATED GUST,
STATION RECORD)

RECORDS FOR SEPTEMBER 22
HIGH 90F IN 1895, 1914
LOW 30F IN 1904 (Earliest freeze)
PRECIP 1.16 INCHES IN 2001
PEAK GUST 60 MPH SSW IN 1989

TODAY’S REPORT PREPARED BY: Amanda Joly