Thursday, December 21, 2023

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

THURSDAY, DECEMBER 21, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0710E
SUNSET:  1615E

CLEAR SKIES, COLD TEMPERATURES, AND A BRISK NORTHERLY WIND….

Today aptly feels like the first day of winter with cold sunshine
and a brisk wind out there today. The solstice officially occurs
at 10:17pm this evening.

Temperatures have struggled into the low to mid 30s despite the
abundance of sunshine. The dew point has been on the decline from
the upper teens early this morning to the lower teens early this
afternoon.

The wind has been on the busy side today out of mainly the north-
northwest. The average speed for the day so far is around 12mph.
The peak gust so far, which occurred around 9:30am this morning
is 29mph.

Visibility has been excellent today, ranging between 60-80 miles.

The maximum temperature for today is 34F degrees, this is 5 degrees
below the normal high of 39F. The minimum temperature since midnight
is 27F degrees, this is 3 degrees above the normal low of 24F.

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Today’s Observations:

7 A.M.
Weather: Clear, few stratocumulus offshore distant NNE-S, few cirrus
distant NE-SSE
Temperature: 27F; Dew Point: 18F; Relative Humidity: 69%
Wind: NNW @ 11G20 kts
Sea-level pressure: 1027.9 mb; 30.35 in. Hg: rising, then more slowly
Visibility: 60 miles
6-hr Max temp: 30F
6-hr Min temp: 27F
24-hr Precip:  0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 CLR 60 279/27/18/3411G20/035/ FEW SC OFFSHR DSNT NNE-S
FEW CI DSNT NE-SSE/ 8/502 51012 10030 20027

10 A.M.
Weather: Clear, few stratocumulus offshore distant NE-SSE
Temperature: 31F; Dew Point: 14F; Relative Humidity: 49%
Wind: NNW @ 12G20 kts
Sea-level pressure: 1029.5 mb; 30.40 in. Hg: rising, then more slowly
Visibility: 80 miles
3-hr Precip:  0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 CLR 80 295/31/14/3412G20/040/ FEW SC OFFSHR DSNT NE-SSE/
8/501 51016

1 P.M.
Weather: Clear, few stratocumulus offshore distant ENE-SSE
Temperature: 33F; Dew Point: 13F; Relative Humidity: 43%
Wind: NNW @ 12G18 kts
Sea-level pressure: 1027.8 mb; 30.35 in. Hg: falling, then more slowly
Visibility: 80 miles
6-hr Max temp: 34F
6-hr Min temp: 27F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 CLR 80 278/33/13/3312G18/035/ FEW SC OFFSHR DSNT ENE-SSE/
8/500 56017 10034 20027

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SUMMARY FOR WEDNESDAY, DECEMBER 20, 2023

TEMPERATURE (DEGREES F)
MAX…….41   NORMAL…..39
MIN…….26   NORMAL…..24
MEAN……34   NORMAL…..31

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………..+3
TOTAL DEPARTURE FOR THE MONTH…………………+110 [+5.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY……………31  DEPARTURE……..-3
TOTAL HEATING UNITS FOR THE MONTH…………..509  DEPARTURE……-111
TOTAL HEATING UNITS FOR THE SEASON…………1596  DEPARTURE……-227
TOTAL HEATING UNITS LAST SEASON TO DATE…….1552  DEPARTURE…….+44

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)……….E26 NNW  @  08:30 P.M.
VECTOR #1 (1-Sec)……….27 NNW  @  08:30 P.M.
VECTOR #2 (1-Sec)……….28 NNW  @  08:29 P.M.
DAVIS #1……………….26 NNW  @  08:37 P.M.
DAVIS #2 ………………26 NNW  @  08:29 P.M.
RMY #1 (Instantaneous)…..28 NNW  @  08:29 P.M.
RMY #2 (Instantaneous)…..28 NNW  @  08:29 P.M.
MERLIN…………………24 NNW
RICHARDS (C5C) (Inst)……27      @  08:29 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………19 NNW  @  08:57 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..18      @  08:30 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..18      @  08:31 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………18 NW   @  08:30 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………18 N    @  08:31 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..18 NNW  @  08:30 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..18 NNW  @  08:30 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………18      @  08:30 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……10.3 NNW [248 total miles] VECTOR #1…………….10.3
VECTOR #2…………….10.5
DAVIS #1……………..10.4 NNW
DAVIS #2……………..10.3 NNW
RMY #1……………….10.1 NNW
RMY #2……………….10.4 NNW
RICHARDS (C5C)………..10.6

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.17
TOTAL PRECIPITATION FOR THE MONTH…………..6.44 DEPARTURE…..+2.88
TOTAL PRECIPITATION FOR THE YEAR…………..57.81 DEPARTURE…..+5.78

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE……-0.5
TOTAL SNOWFALL FOR THE MONTH………………..0.3 DEPARTURE……-6.8
TOTAL SNOWFALL FOR THE SEASON (2023-2024)…….0.3 DEPARTURE……-9.3

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PRELIMINARY CLIMATE SUMMARY FOR DECEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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

12/1  51/38/45/+8/0.04/0.0/213/38         29 SW  VEC1 28 SW  RMY 29
12/2  48/43/46/+9/T/0.0/000/00            18 SSW VEC1 19 SSW RMY 19
12/3  44/41/43/+7/0.76/0.0/000/00         31 ENE VEC1 32 ENE RMY 33
12/4  49/37/43/+7/0.07/0.0/155/28         23 W   VEC1 22 W   RMY 23
12/5  38/28/33/-3/0.00/0.0/144/26         23 NNW VEC1 24 NW  RMY 24
12/6  34/22/28/-7/0.01/0.3/100/18         21 N   VEC1 21 N   RMY 20
12/7  28/17/56/-12/0.00/0.0/121/22        18 NNW VEC1 18 NW  RMY 19
12/8  42/24/33/-2/0.00/0.0/530/96         20 S   VEC1 18 S   RMY 18
12/9  52/33/43/+9/0.00/0.0/264/48         24 S   VEC1 24 S   RMY 24
12/10 60/43/52/+18/0.66/0.0/033/06        55 SSW VEC1 54 SSW RMY 53
12/11 61/33/47/+13/1.96/0.0/038/07        69 SSW VEC1 69 SSW RMY 71
12/12 42/29/36/+2/0.00/0.0/543/99         33 WNW VEC1 32 WNW RMY 34
12/13 43/28/36/+3/0.00/0.0/470/86         36 WNW VEC1 34 WNW RMY 36
12/14 34/22/28/-5/0.00/0.0/520/95         31 SW  VEC1 31 SW  RMY 32
12/15 53/30/42/+9/0.00/0.0/541/99         31 WNW VEC1 30 WNW RMY 28
12/16 50/36/43/+11/0.00/0.0/530/97        21 ESE VEC1 22 ESE RMY 22
12/17 55/37/46/+14/0.47/0.0/098/18        40 SSE VEC1 41 SSE RMY 41
12/18 61/42/52/+20/2.47/0.0/000/00        90 SSE VEC1 95 SSE RMY 101
12/19 46/30/38/+6/0.00/0.0/332/61         28 NW  VEC1 28 NW  RMY 26
12/20 41/26/34/+3/0.00/0.0/540/99         26 NNW VEC1 27 NNW RMY 28

12/21 The low since midnight is 27F, the daily normal low is 24F

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DECEMBER DAILY RECORDS TO DATE

12/18: RECORD MAXIMUM TEMPERATURE OF 61F;
BEATS OLD RECORD OF 59F SET IN 1928

12/18: RECORD PRECIPITATION OF 2.47 INS;
BEATS OLD RECORD OF 1.44 INS SET IN 1915

12/18: RECORD PEAK WIND GUST OF 90 MPH;
BEATS OLD RECORD OF 76e MPH SET IN 1978

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

RECORDS FOR DECEMBER 21
HIGH 62 IN 2018
LOW -10 IN 1942
PRECIP 2.37 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957

RECORDS FOR DECEMBER 22
HIGH 63 IN 2013
LOW -5 IN 1921
PRECIP 1.52 INS. IN 1975
SNOWFALL 8.8 INS. IN 1975
PEAK GUST 62 MPH WNW IN 1998

TODAY’S REPORT PREPARED BY: Matt Douglas