Saturday, October 21, 2023

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

SATURDAY, OCTOBER 21, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0604E
SUNSET:  1653E

RAINY DAY WITH SIGNIFICANT PRESSURE DECREASE

Before observation time visibility was around 30 miles and
an undercast layer of fog was observed in the area. Around
the 7 A.M. observation time, light drizzle began and a thick
fog layer engulfed the hill reducing visibility to 1/4 mile
for the rest of the day. Heavier precipitation came just after
11 A.M. and continued throughout observation time. A total of
0.13 inches of precipitation has been measured so far today.

We observed a significant drop in pressure of over 25 millibars
from 1010.6mb to 985.2mb since yesterday afternoon.

The temperature and dew points stayed consistent in the high
50’s today with 100% humidity.

The maximum temperature so far today has been 58F, which is 2
degrees above the normal high of 60F. The minimum temperature
since midnight is 55F, which is 13 degrees above the normal low
of 42F.

As we continue to remain above normal in the minimum temperature
category, we are actively tracking when we will have our first
low temperature below 40F. Here are the current rankings as
compiled by our Chief Scientist, Mike Iacono.

BHO Latest First Minimum Temperature Below 40 deg F (1885-2023):

1) 24 October 2013 (36F)
24 October 2021 (37F)
3) 22 October 1955 (34F)
4) 21 October 2005 (39F)
5) 20 October 1960 (38F)
6) 19 October 2014 (39F)

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Today’s Observations:

7 A.M.
Weather: Overcast stratus fractus, light drizzle
Temperature: 57F; Dew Point: 57F; Relative Humidity: 100%
Wind: SE @ 5 kts, wind light
Sea-level pressure: 993.3 mb; 29.33 in. Hg: falling steadily
Visibility: 1/4 mile, fog
6-hr Max temp: 57F
6-hr Min temp: 55F
24-hr Precip: 0.02 inches
BHO SA 1155 X W3 1/4L-F 933/57/57/1305/933/ WND LGT/ 8////
57021 70002 10057 20055

10 A.M.
Weather: Overcast stratus fractus, light drizzle
Temperature: 58F; Dew Point: 58F; Relative Humidity: 100%
Wind: E @ 10 kts
Sea-level pressure: 989.1 mb; 29.21 in. Hg: falling, then more
rapidly
Visibility: 1/4 mile, fog
3-hr Precip: 0.01 inches
BHO SA 1455 X W3 1/4L-F 891/58/58/0910/921/ 8//// 58042 6001/

1 P.M.
Weather: Overcast stratus fractus, light rain
Temperature: 56F; Dew Point: 56F; Relative Humidity: 100%
Wind: E @ 10 kts
Sea-level pressure: 985.2 mb; 29.09 in. Hg: falling, then more
rapidly
Visibility: 1/4 mile, fog
6-hr Max temp: 58F
6-hr Min temp: 56F
6-hr Precip: 0.11 inches
BHO SA 1755 X W3 1/4R-F 852/56/56/0910/909/ 8//// 58039 6011/
10058 20056

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SUMMARY FOR FRIDAY, OCTOBER 20, 2023

TEMPERATURE (DEGREES F)
MAX…….63   NORMAL…..60
MIN…….50   NORMAL…..42
MEAN……57   NORMAL…..51

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……….+6
TOTAL DEPARTURE FOR THE MONTH…………………+82 [+3.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY…………….8  DEPARTURE……..-6
TOTAL HEATING UNITS FOR THE MONTH…………..143  DEPARTURE…….-73
TOTAL HEATING UNITS FOR THE SEASON………….242  DEPARTURE…….-92
TOTAL HEATING UNITS LAST SEASON TO DATE……..293  DEPARTURE…….-51

COOLING DEGREE DAYS (SEASON: JAN 2023 THRU DEC 2023)
TOTAL COOLING UNITS FOR YESTERDAY…………….0  DEPARTURE………0
TOTAL COOLING UNITS FOR THE MONTH……………15  DEPARTURE……..+8
TOTAL COOLING UNITS FOR THE SEASON………….704  DEPARTURE…….+27
TOTAL COOLING UNITS LAST SEASON TO DATE……..884  DEPARTURE……-180

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)……….E28 SSE  @  12:52 P.M.
VECTOR #1 (1-Sec)……….26 SE   @  08:41 P.M.
VECTOR #2 (1-Sec)……….26 SSE  @  12:52 P.M.
DAVIS #1……………….25 SSE  @  12:50 P.M.
DAVIS #2 ………………27 S    @  04:06 A.M.
RMY #1 (Instantaneous)…..26 SE   @  08:31 P.M.
RMY #2 (Instantaneous)…..28 SSE  @  12:52 P.M.
MERLIN…………………23 S
RICHARDS (C5C) (Inst)……24      @  12:52 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………18* SE  @  08:31 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..18      @  08:20 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..19      @  08:26 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………18 ESE  @  08:33 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………21 S    @  04:43 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..18 SE   @  08:23 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..19 SSW  @  08:26 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………19      @  08:31 P.M.

*ADDITIONAL FASTEST MILE 18 ESE @ 08:26 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…….11.6 SSE [279 total miles] VECTOR #1……………..11.9
VECTOR #2……………..12.9
DAVIS #1………………11.6 SSE
DAVIS #2………………12.6 SSE
RMY #1………………..11.6 SSE
RMY #2………………..13.0 SSE
RICHARDS (C5C)…………12.1

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.02 DEPARTURE…..-0.17
TOTAL PRECIPITATION FOR THE MONTH…………..0.25 DEPARTURE…..-3.23
TOTAL PRECIPITATION FOR THE YEAR…………..47.47 DEPARTURE…..+5.32

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PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 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

10/1  68/50/59/+1/0.00/458/65             20 NNE VEC1 20 NNE RMY 19
10/2  68/55/62/+4/0.00/681/97             24 NE  VEC1 23 NE  RMY 24
10/3  81/54/68/+11/0.00/672/96            18 WSW VEC1 18 WSW RMY 18
10/4  81/64/73/+16/0.00/669/96            17 S   VEC1 17 S   RMY 16
10/5  77/59/68/+11/0.00/638/92            24 S   VEC1 24 S   RMY 23
10/6  71/60/66/+10/0.00/269/39            20 SE  VEC1 19 SE  RMY 18
10/7  68/54/61/+5/0.16/007/01             30 WNW VEC1 29 WNW RMY 29
10/8  63/48/56/+1/0.00/651/95             30 W   VEC1 30 WNW RMY 30
10/9  61/44/53/-2/0.00/532/78             25 WSW VEC1 24 WSW RMY 25
10/10 64/47/56/+1/T/245/36                23 W   VEC1 22 W   RMY 21
10/11 68/50/59/+5/0.00/393/58             23 SSW VEC1 22 SW  RMY 22
10/12 69/51/60/+6/0.00/479/71             18 NW  VEC1 18 NNW RMY 18
10/13 61/43/52/-2/0.00/638/95             33 NW  VEC1 31 NW  RMY 34
10/14 60/44/52/-1/0.00/247/37             24 NW  VEC1 23 NW  RMY 23
10/15 59/44/52/-1/0.00/226/34             24 NNW VEC1 25 NNW RMY 25
10/16 58/44/51/-1/0.07/166/25             17 WNW VEC1 17 WNW RMY 17
10/17 60/45/53/+1/T/211/32                15 N   VEC1 15 N   RMY 14
10/18 62/49/56/+4/0.00/079/12             15 SSW VEC1 15 SSW RMY 16
10/19 65/50/58/+8/0.00/…/..             31 SSW VEC1 30 SSW RMY 33
10/20 63/55/57/+6/…./…/..             28 SSE VEC1 26 SE  RMY 26

10/21 The low since midnight is 55F, the daily normal low is 42F

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OCTOBER DAILY RECORDS TO DATE

.NONE…

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

RECORDS FOR OCTOBER 21
HIGH 79F IN 1979
LOW 24F IN 1974
PRECIP 2.34 INCHES IN 1944
SNOWFALL TRACE IN 1895,1907,1941
PEAK GUST 69e MPH S IN 1976

RECORDS FOR OCTOBER 22
HIGH 85F IN 1979
LOW 23F IN 1940
PRECIP 2.38 INCHES IN 2014
SNOWFALL TRACE IN 1969, 2010
PEAK GUST 67 MPH ESE IN 1988

TODAY’S REPORT PREPARED BY: Kaitlin Geagan