Thursday, December 19, 2024

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

THURSDAY, DECEMBER 19, 2024
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0709E
SUNSET:  1614E

OVERNIGHT RAIN SYSTEM MOVES OUT, A MIX OF CLOUDS AND SUN WITH A BRISK
NORTHWEST WIND IN ITS WAKE….

Another in a series of clipper systems moved through overnight bringing
the area another dose of rainfall. 0.70″ of water was deposited in the
gauge, bringing the monthly total to nearly 5.50 inches. This will assure
that the month of December will end with above normal precipitation.
With that said, there has been marked improvement in the drought situation
according to the latest Drought Monitor report issued this morning.
However, we are still considered to be in the moderate to severe drought
category.

Skies cleared for a time this morning, but clouds re-developed by mid
to late morning leaving us with a mix of clouds and sun into early this
afternoon.

Temperatures are cooler than they were yesterday, but still above normal
for the date. Readings started the day in the mid 30s, but recovered to
the low to mid 40s by early this afternoon.

Winds have become gusty as diurnal heating allows for mixing from aloft.
The average speed for the day so far is around 11mph, out of mainly the
northwest. The peak gust for the day so far is 31mph, which occurred at
10:37am this morning.

Visibility has been improving through the day, from 50 miles early this
morning to 70-80 miles by early this afternoon.

The maximum temperature for today is 44F degrees, which is 4 degrees
above the normal high of 40F. The minimum temperature since midnight
is 34F degrees, which is 10 degrees above the normal low of 24F.

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Today’s Observations:

7 A.M.
Weather: Scattered cirrostratus, scattered cirrus, few stratocumulus
distant NNW-ESE, few altocumulus/castellanus distant W-NNW
Temperature: 34F; Dew Point: 33F; Relative Humidity: 96%
Wind: WNW @ 10 kts
Sea-level pressure: 1018.7 mb; 30.08 in. Hg: rising, then more rapidly
Visibility: 50 miles
6-hr Max temp: 38F
6-hr Min temp: 34F
24-hr Precip:  0.70 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 200 SCT 250 SCT 50 187/34/33/3010/008/ FEW SC DSNT NNE-ESE
FEW AC/ACC DSNT W-NNW/ 8/588 53035 6008/ 70070 10038 20034

10 A.M.
Weather: Clear, few stratocumulus all quadrants, few cirrostratus distant
E-SSW, virga distant NW-NNE
Temperature: 40F; Dew Point: 32F; Relative Humidity: 73%
Wind: NW @ 12G20 kts
Sea-level pressure: 1021.6 mb; 30.17 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 70 216/40/32/3112G20/017/ FEW SC ALQDS FEW CS DSNT E-SSW
VIRGA DSNT NW-NNE/ 8/508 51029

1 P.M.
Weather: Scattered stratocumulus, thin scattered cirrus
Temperature: 42F; Dew Point: 28F; Relative Humidity: 56%
Wind: NNW @ 12G20 kts
Sea-level pressure: 1021.6 mb; 30.17 in. Hg: falling, then rising
Visibility: 80 miles
6-hr Max temp: 44F
6-hr Min temp: 34F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 35 SCT 250 -SCT 80 216/42/28/3312G20/017/ 8/501 55000
10044 20034

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SUMMARY FOR WEDNESDAY, DECEMBER 18, 2024

TEMPERATURE (DEGREES F)
MAX…….50  NORMAL…..40
MIN…….36  NORMAL…..24
MEAN……43  NORMAL…..32

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………+11
TOTAL DEPARTURE FOR THE MONTH…………………….+2 [-0.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………22  DEPARTURE…….-11
TOTAL HEATING UNITS FOR THE MONTH…………..550  DEPARTURE……..-2
TOTAL HEATING UNITS FOR THE SEASON…………1493  DEPARTURE……-263
TOTAL HEATING UNITS LAST SEASON TO DATE…….1538  DEPARTURE…….-45

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)………..21 S    @   05:31 P.M.
VECTOR #1 (1-Sec)……….21 S    @   05:24 P.M.
VECTOR #2 (1-Sec)……….21 SSE  @   05:26 P.M.
DAVIS #1……………….21 S    @   05:29 P.M.
DAVIS #2 ………………21 S    @   04:53 P.M.
RMY #1 (Instantaneous)…..21 S    @   04:51 P.M.
RMY #2 (Instantaneous)…..22 SSE  @   05:26 P.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………16 S    @   05:38 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..16      @   04:52 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..17      @   04:52 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 S    @   05:55 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………21 S    @   04:53 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 S    @   04:52 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..17 S    @   04:52 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………8.7 WSW [209 total miles] VECTOR #1……………….9.1
VECTOR #2……………….9.5
DAVIS #1………………..9.1 WSW
DAVIS #2………………..9.5 WSW
RMY #1………………….8.8 WSW
RMY #2………………….9.5 WSW
RICHARDS (C5C)…………..OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.70 DEPARTURE…..+0.53
TOTAL PRECIPITATION FOR THE MONTH…………..5.49 DEPARTURE…..+2.28
TOTAL PRECIPITATION FOR THE YEAR (2024)…….52.96 DEPARTURE…..+1.28

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……-3.1
TOTAL SNOWFALL FOR THE SEASON (2024-2025)…….3.0 DEPARTURE……-5.6

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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 The low since midnight is 34F, 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 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

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

TODAY’S REPORT PREPARED BY: Matt Douglas