Friday, December 20, 2024

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

FRIDAY, DECEMBER 20, 2024
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0710E
SUNSET:  1614E

COASTAL STORM TRANSFORMS BLUE HILL INTO A WINTER WONDERLAND
TODAY….

Snowflakes made their appearance to Blue Hill early this morning
and have continued throughout the day. We had a trace accumulation
by 7am, but as heavier snowfall moved into the area, we ended up
with 2 inches by 1pm. It is still snowing and the temperature continues
to drop so more accumulation may be possible.

Temperatures have been holding steady at 30F and 31F during the day.
With obscured and overcast skies, it’s not a surprise that the
temperatures haven’t varied much.

Winds have been mostly out of the northeast and east northeast, thanks
to that coastal front pushing through. The wind shifted to a more
northerly flow before the 1pm observation and the wind speed decreased
quite a bit. The average speed for the day so far is around 10mph. The
peak gust for the day so far is 24mph, which occurred at 5:35am this
morning.

Visibility has been abysmal. We were around 5 miles at 7am when the
front started to move in and finished the day at only 1/8 mile. Fog
and snow conditions were to blame for both the low ceiling and poor
visibility.

The maximum temperature for today is 32F degrees, which is 7 degrees
below the normal high of 39F. The minimum temperature since midnight
is 28F degrees, which is 4 degrees above the normal low of 24F.

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Today’s Observations:

7 A.M.
Weather: Overcast stratus, snow showers, precipitation very light
Temperature: 31F; Dew Point: 30F; Relative Humidity: 95%
Wind: ENE @ 10 kts
Sea-level pressure: 1024.2 mb; 30.24 in. Hg: falling unsteady
Visibility: 5 miles, fog
6-hr Max temp: 31F
6-hr Min temp: 28F
24-hr Precip:  0.00 inches
24-hr Snowfall: Trace
Snow Depth: Trace
BHO SA 1155 E2 OVC 5S-F 242/31/30/0610/024/ PCPN VRY LGT TOTAL NEW
SNW PST 24 HRS TRACE/ 8/6// 4/000 57013 10031 20028

10 A.M.
Weather: Sky obscured, vertical visibility 200 ft, snow showers
Temperature: 31F; Dew Point: 31F; Relative Humidity: 100%
Wind: NNE @ 11 kts
Sea-level pressure: 1022.8 mb; 30.20 in. Hg: falling, then more
rapidly
Visibility: 1/4 mile, fog
3-hr Precip:  0.06 inches
3-hr Snowfall: 0.6 inches
BHO SA 1455 X W2 1/4S-F 228/31/31/0211/020/ NEW SNW PST 3 HRS 0.6 INS/
8//// 58014 6006/

1 P.M.
Weather: Sky obscured, vertical visibility 200 ft, snow showers
Temperature: 30F; Dew Point: 30F; Relative Humidity: 100%
Wind: N @ 8 kts
Sea-level pressure: 1018.4 mb; 30.07 in. Hg: falling, then more slowly
Visibility: 1/8 mile
6-hr Max temp: 32F
6-hr Min temp: 30F
6-hr Precip:  0.27 inches
6-hr Snowfall: 2.0 inches
Snow Depth: 2 inches
BHO SA 1755 X W2 1/8S-F 184/30/30/3508/007/ NEW SNW PST 6 HRS 1.4 INS/
8//// 4/002 56044 6027/ 10032 20030

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SUMMARY FOR THURSDAY, DECEMBER 19, 2024

TEMPERATURE (DEGREES F)
MAX…….44  NORMAL…..39
MIN…….30  NORMAL…..24
MEAN……37  NORMAL…..32

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………….+5
TOTAL DEPARTURE FOR THE MONTH…………………….+7 [+0.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………28  DEPARTURE…….-11
TOTAL HEATING UNITS FOR THE MONTH…………..578  DEPARTURE……..-8
TOTAL HEATING UNITS FOR THE SEASON…………1521  DEPARTURE……-269
TOTAL HEATING UNITS LAST SEASON TO DATE…….1565  DEPARTURE…….-44

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)………..31 NW   @   10:37 A.M.
VECTOR #1 (1-Sec)……….31 NW   @   10:37 A.M.
VECTOR #2 (1-Sec)……….33 NW   @   10:37 A.M.
DAVIS #1……………….31 WNW  @   10:11 A.M.
DAVIS #2 ………………31 WNW  @   10:37 A.M.
RMY #1 (Instantaneous)…..32 NW   @   10:37 A.M.
RMY #2 (Instantaneous)…..35 NW   @   10:36 A.M.
MERLIN…………………31 NW
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………22 NW   @   10:13 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..22      @   10:13 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..22      @   10:05 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………23 WNW  @   10:13 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………21 NW   @   10:05 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..22 NW   @   10:13 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..21 NW   @   10:05 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..10.0 NW  [240 total miles] VECTOR #1……………….9.9
VECTOR #2………………10.5
DAVIS #1……………….10.0 NW
DAVIS #2………………..9.6 NNW
RMY #1………………….9.7 NNW
RMY #2…………………10.3 NNW
RICHARDS (C5C)…………..OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….Trace DEPARTURE…..-0.18
TOTAL PRECIPITATION FOR THE MONTH…………..5.49 DEPARTURE…..+2.10
TOTAL PRECIPITATION FOR THE YEAR (2024)…….52.96 DEPARTURE…..+1.10

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………Trace DEPARTURE……-0.5
TOTAL SNOWFALL FOR THE MONTH………………..3.0 DEPARTURE……-3.6
TOTAL SNOWFALL FOR THE SEASON (2024-2025)…….3.0 DEPARTURE……-6.1

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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 The low since midnight is 28F, the daily normal low is 24F.

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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 20
HIGH 61 IN 1957
LOW -16 IN 1942
PRECIP 1.69 INS. IN 1936
SNOWFALL 13.7 INS. IN 2009
PEAK GUST 75 MPH S IN 2002

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

TODAY’S REPORT PREPARED BY: Amanda Joly