Wednesday, December 18, 2024

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

WEDNESDAY, DECEMBER 18, 2024
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0709E
SUNSET:  1614E

A VERY PLEASANT DAY WITH CONTINUED MILD TEMPERATURES AND LIGHT WIND….

What a difference a year makes! Last year on this date we were dealing
with a very strong storm system that brought heavy rain and very strong
winds to the region. Here at Blue Hill, we had a record setting wind
gust to 90mph as well as a record precipitation amount of 2.47″. It
was also a warm day with a new record high of 61F!

Nothing close to that today as we enjoy a mainly sunny sky with light
winds and rather mild temperatures for this time of year. High thin
clouds have been streaming in, filtering the sun a bit today as our next
system approaches the region from the west.

Temperatures are again on the mild side today with readings reaching
50 degrees. While not as “warm” as yesterday, it’s still a solid 10
degrees above the normal values expected for the date! The dew point
has been holding in the low to mid 30s all day.

Winds have been considerably lighter today than yesterday. It has been
varying a bit between the west and southwest, but the average speed for
the day so far has only been around 9mph. The peak gust for the day
occurred just after 12:30am with a value of 20mph.

Visibility hasn’t been great, but it’s been gradually improving
through the day. It started the day around 30 miles early this morning,
reaching 50 miles by early this afternoon.

The maximum temperature for today is 50F degrees, which is 10 degrees
above the normal high of 40F. The minimum temperature since midnight
is 36F degrees, which is 12 degrees above the normal low of 24F.

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Today’s Observations:

7 A.M.
Weather: Thin broken cirrus
Temperature: 37F; Dew Point: 32F; Relative Humidity: 84%
Wind: WSW @ 7 kts
Sea-level pressure: 1024.9 mb; 30.27 in. Hg: rising, then more slowly
Visibility: 30 miles
6-hr Max temp: 40F
6-hr Min temp: 36F
24-hr Precip:  Trace
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 E250 -BKN 30 249/37/32/2407/027/ 8/001 51016 70000 10040 20036

10 A.M.
Weather: Thin broken cirrus
Temperature: 42F; Dew Point: 35F; Relative Humidity: 73%
Wind: W @ 6 kts, wind light
Sea-level pressure: 1024.7 mb; 30.26 in. Hg: rising, then falling
Visibility: 40 miles
3-hr Precip:  0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 E250 -BKN 40 247/42/35/2606/026/ WND LGT/ 8/001 58002

1 P.M.
Weather: Scattered cirrocumulus, thin broken cirrus, few altocumulus/
castellanus distant WNW-N
Temperature: 49F; Dew Point: 35F; Relative Humidity: 56%
Wind: SW @ 8 kts
Sea-level pressure: 1021.6 mb; 30.17 in. Hg: falling, then more slowly
Visibility: 50 miles
6-hr Max temp: 50F
6-hr Min temp: 37F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 200 SCT E250 -BKN 50 216/49/35/2208/017/ FEW AC/ACC DSNT
WNW-N/ 8/089 56031 10050 20037

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SUMMARY FOR TUESDAY, DECEMBER 17, 2024

TEMPERATURE (DEGREES F)
MAX…….59  NORMAL…..40
MIN…….41  NORMAL…..25
MEAN……50  NORMAL…..32

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………+18
TOTAL DEPARTURE FOR THE MONTH…………………….-9 [-0.7 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………15  DEPARTURE…….-18
TOTAL HEATING UNITS FOR THE MONTH…………..528  DEPARTURE……..+9
TOTAL HEATING UNITS FOR THE SEASON…………1471  DEPARTURE……-252
TOTAL HEATING UNITS LAST SEASON TO DATE…….1525  DEPARTURE…….-54

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)………..48 SSW  @   03:00 A.M.
VECTOR #1 (1-Sec)……….50 SSW  @   03:00 A.M.
VECTOR #2 (1-Sec)……….46 S    @   03:00 A.M.
DAVIS #1……………….50 S    @   02:59 A.M.
DAVIS #2 ………………54 S    @   03:41 A.M.
RMY #1 (Instantaneous)…..50 SSW  @   04:39 A.M.
RMY #2 (Instantaneous)…..49 SSW  @   04:25 A.M.
MERLIN…………………45 SSW
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………33 S    @   03:19 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..34      @   03:01 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..35      @   03:01 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………35 S    @   03:02 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………38 S    @   03:50 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..34 SSW  @   03:01 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..35 S    @   03:50 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..17.1 W [410 total miles] VECTOR #1………………16.7
VECTOR #2………………17.6
DAVIS #1……………….17.0 SW
DAVIS #2……………….17.7 WSW
RMY #1…………………16.1 WSW
RMY #2…………………17.4 WSW
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…………..4.79 DEPARTURE…..+1.75
TOTAL PRECIPITATION FOR THE YEAR (2024)…….52.26 DEPARTURE…..+0.75

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE……-0.4
TOTAL SNOWFALL FOR THE MONTH………………..3.0 DEPARTURE……-2.7
TOTAL SNOWFALL FOR THE SEASON (2024-2025)…….3.0 DEPARTURE……-5.2

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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/…/..        51 WNW VEC1 49 WNW RMY 51
12/13  31/19/25/-8/0.00/0.0/…/..        30 WNW VEC1 30 W   RMY 30
12/14  33/17/25/-8/0.00/0.0/…/..        20 NW  VEC1 19 NNW RMY 20
12/15  34/17/26/-7/0.00/0.0/…/..        17 N   VEC1 17 N   RMY 16
12/16  45/29/37/+5/T/0.0/…/..           35 SSE VEC1 35 SSE RMY 35
12/17  59/41/50/+18/0.25/0.0/…/..       48 SSW VEC1 50 SSW RMY 50

12/18 The low since midnight is 36F, 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 18
HIGH 61 IN 2023
LOW -11 IN 1919
PRECIP 2.47 INS. IN 2023
SNOWFALL 7.0 INS. IN 1904
PEAK GUST 90 SSE IN 2023

RECORDS FOR DECEMBER 19
HIGH 59 IN 1899
LOW -1 IN 1919
PRECIP 2.06 INS. IN 1986
SNOWFALL 14.1 INS. IN 1945
PEAK GUST 68 NE IN 1986

TODAY’S REPORT PREPARED BY: Matt Douglas