Sunday, December 22, 2024

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

SUNDAY, DECEMBER 22, 2024
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0711E
SUNSET:  1615E

SUNNY BUT COLD AND BLUSTERY TODAY AT BLUE HILL….

It is COLD today! Our overnight low reached 6F which is the first
time we have been below 10F for the year and also makes it the
lowest temperature of 2024 to date. This is the coldest reading we
have had since February 4, 2023 when the temperature dipped to an
impressive -14F!

Despite the cold air, we have had mostly clear skies today with
plenty of sunshine. The only clouds that have been observed have
been offshore which is due to some ocean effect snow showers that
have been impacting the outer Cape region throughout the day.

The sun has unfortunately not been successful in warming us much
today, as we have not even hit 20F by the early afternoon. This dry
Arctic air mass has kept us way below normal for the day with dew
points in the single digits. Very dry and very cold has been the
theme for today!

With such frigid temperatures, any wind has added a chill to the
air and the wind has been fairly active today, giving us wind chill
values from below 0 and ‘up’ to the single digits. The wind has been
mostly from the northwest and we are averaging around 15 mph. The
peak gust so far for the day occurred just after midnight at around
33 mph.

Visibility has been exceptional, which would be expected given the
dry air. We started at around 50 miles at sunrise and were at around
80 miles by the 1pm observation.

The maximum temperature for today is 17F degrees, which is 22 degrees
below the normal high of 39F. The minimum temperature since midnight
is 6F degrees, which is 17 degrees below the normal low of 23F.
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Today’s Observations:

7 A.M.
Weather: Clear, few stratocumulus offshore distant NNE-E-S
Temperature: 7F; Dew Point: 2F; Relative Humidity: 83%
Wind: NW @ 12 kts
Sea-level pressure: 1025.0 mb; 30.27 in. Hg: rising, then more slowly
Visibility: 50 miles
6-hr Max temp: 12F
6-hr Min temp: 6F
24-hr Precip:  0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 7 inches
BHO SA 1155 CLR 50 250/7/2/3212/027/ FEW SC OFFSHR DSNT NNE-E-S/ 8/500
4/007 51033 10012 20006

10 A.M.
Weather: Clear, few stratocumulus offshore distant NNE-E-S
Temperature: 12F; Dew Point: 1F; Relative Humidity: 61%
Wind: NNW @ 11G19 kts
Sea-level pressure: 1028.1 mb; 30.36 in. Hg: rising, then more slowly
Visibility: 70 miles
3-hr Precip:  0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 CLR 70 281/12/1/3311G19/036/ FEW SC OFFSHR DSNT NNE-E-S/
8/500 51031

1 P.M.
Weather: Clear, few stratocumulus offshore distant NNE-E-SSE
Temperature: 17F; Dew Point: 1F; Relative Humidity: 48%
Wind: NNW @ 9 kts
Sea-level pressure: 1027.7 mb; 30.35 in. Hg: steady, then falling
Visibility: 80 miles
6-hr Max temp: 17F
6-hr Min temp: 6F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 7 inches
BHO SA 1755 CLR 80 277/17/1/3309/035/ FEW SC OFFSHR DSNT NNE-E-SSE/
8/500 4/007 58004 10017 20006

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SUMMARY FOR SATURDAY, DECEMBER 21, 2024

TEMPERATURE (DEGREES F)
MAX…….26  NORMAL…..39
MIN…….12  NORMAL…..24
MEAN……19  NORMAL…..31

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………-12
TOTAL DEPARTURE FOR THE MONTH…………………….-8 [-0.6 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………46  DEPARTURE…….+12
TOTAL HEATING UNITS FOR THE MONTH…………..661  DEPARTURE……..+8
TOTAL HEATING UNITS FOR THE SEASON…………1604  DEPARTURE……-253
TOTAL HEATING UNITS LAST SEASON TO DATE…….1634  DEPARTURE…….-30

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

F420C (Official)………..38 NW   @   07:34 P.M.
VECTOR #1 (1-Sec)……….38 NW   @   07:34 P.M.
VECTOR #2 (1-Sec)……….39 NW   @   06:56 P.M.
DAVIS #1……………….38 WNW  @   07:34 P.M.
DAVIS #2 ………………35 WNW  @   06:56 P.M.
RMY #1 (Instantaneous)…..41 NW   @   07:34 P.M.
RMY #2 (Instantaneous)…..42 NW   @   03:32 P.M.
MERLIN…………………38 NW
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………26 NW   @   07:36 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..25      @   06:58 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..27      @   07:36 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………26 NW   @   07:36 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………26 NW   @   07:36 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..25 NW   @   06:58 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..26 NW   @   07:36 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..14.5 NW [347 total miles] VECTOR #1………………14.1
VECTOR #2………………14.8
DAVIS #1……………….13.6 NW
DAVIS #2……………….13.8 NNW
RMY #1…………………14.0 NW
RMY #2…………………14.4 NW
RICHARDS (C5C)…………..OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.18
TOTAL PRECIPITATION FOR THE MONTH…………..6.66 DEPARTURE…..+2.92
TOTAL PRECIPITATION FOR THE YEAR (2024)…….54.13 DEPARTURE…..+1.92

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE……-0.5
TOTAL SNOWFALL FOR THE MONTH……………….12.4 DEPARTURE……+4.8
TOTAL SNOWFALL FOR THE SEASON (2024-2025)……12.4 DEPARTURE……+2.3

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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   37/23/30/-7/0.00/0.0/452/81        21 WSW VEC1 21 WSW RMY 21
12/2   38/22/30/-7/0.00/0.0/551/99        18 W   VEC1 18 W   RMY 18
12/3   36/20/28/-8/0.00/0.0/411/74        21 NW  VEC1 21 WNW RMY 21
12/4   39/22/31/-5/0.13/T/394/71          30 S   VEC1 31 S   RMY 33
12/5   37/31/34/-2/0.40/3.0/072/13        43 WNW VEC1 43 WNW RMY 47
12/6   31/23/27/-8/0.00/0.0/514/93        39 NW  VEC1 39 W   RMY 42
12/7   37/22/30/-5/T/T/408/74             25 S   VEC1 25 S   RMY 26
12/8   47/28/38/+3/0.02/T/198/36          37 SSW VEC1 37 SSW RMY 40
12/9   47/34/41/+7/0.41/0.0/187/34        28 ENE VEC1 28 E   RMY 29
12/10  42/31/37/+3/0.15/0.0/000/00        31 NE  VEC1 32 NE  RMY 34
12/11  62/36/49/+15/3.38/0.0/000/00       65 SSW VEC1 67 SSW RMY 70 TSTM
12/12  53/25/39/+5/0.05/0.0/460/84        51 WNW VEC1 49 WNW RMY 51
12/13  31/19/25/-8/0.00/0.0/514/94        30 WNW VEC1 30 W   RMY 30
12/14  33/17/25/-8/0.00/0.0/546/100       20 NW  VEC1 19 NNW RMY 20
12/15  34/17/26/-7/0.00/0.0/377/69        17 N   VEC1 17 N   RMY 16
12/16  45/29/37/+5/T/0.0/005/01           35 SSE VEC1 35 SSE RMY 35
12/17  59/41/50/+18/0.25/0.0/360/66       48 SSW VEC1 50 SSW RMY 50
12/18  50/36/43/+11/0.57/0.0/507/93       21 S   VEC1 21 S   RMY 21
12/19  44/30/37/+5/0.13/0.0/…/..        31 NW  VEC1 31 NW  RMY 32
12/20  32/24/28/-3/1.17/9.4/000/00        28 NNE VEC1 29 N   RMY 29
12/21  26/12/19/-12/0.00/0.0/…/..       38 NW  VEC1 38 NW  RMY 41

12/22 The low since midnight is 6F, the daily normal low is 23F.

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DECEMBER DAILY RECORDS TO DATE

12/11 NEW PRECIPITATION RECORD OF 3.38″; OLD RECORD 2.36″ IN 1992

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

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

RECORDS FOR DECEMBER 23
HIGH 62 IN 1990
LOW -1 IN 1989
PRECIP 1.53 INS. IN 1994
SNOWFALL 11.9 INS. IN 1947
PEAK GUST 74 SE IN 2022

TODAY’S REPORT PREPARED BY: Amanda Joly