Saturday, December 23, 2023

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

SATURDAY, DECEMBER 23, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0711E
SUNSET:  1616E

SEASONABLE LATE DECEMBER DAY WITH MIX OF SUN AND CLOUDS….

Mostly clear skies early this morning have given way to a mix
of sun and high cirrocumulus and cirrus clouds. Sunshine, combined
with seasonable temperatures and a light breeze, have made for a
nice day so far on the hill.

Temperatures have been around normal for this time of year, beginning
in the mid 20s this morning and rising to the low 40s by early afternoon.
The dew point has been steadily climbing from the upper teens to the mid
20s.

The wind has been consistently light throughout the day, and our
average so far is only 7mph. The prevailing direction is out of the
south. Our peak gust for the day is not all that impressive either, a
mere 16mph just after noontime.

Visibility has been fairly good, hovering between 40-60 miles.

The maximum temperature for today is 40F degrees, this is 2 degrees
above the normal high of 38F. The minimum temperature since midnight
is 26F degrees, this is 3 degrees above the normal low of 23F.

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Today’s Observations:

7 A.M.
Weather: Clear, few altocumulus all quadrants, few cirrus all quadrants
Temperature: 29F; Dew Point: 17F; Relative Humidity: 62%
Wind: S @ 7 kts
Sea-level pressure: 1033.9 mb; 30.53 in. Hg: rising, then more slowly
Visibility: 40 miles
6-hr Max temp: 29F
6-hr Min temp: 26F
24-hr Precip:  0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 CLR 40 339/29/17/1807/053/ FEW AC ALQDS FEW CI ALQDS/
8/051 51005 10029 20026

10 A.M.
Weather: Scattered cirrocumulus, thin scattered cirrus,
thin smoke layer NW-N-NNE
Temperature: 35F; Dew Point: 20F; Relative Humidity: 55%
Wind: SSE @ 5 kts, wind light
Sea-level pressure: 1034.2 mb; 30.54 in. Hg: rising, then falling
Visibility: 60 miles
3-hr Precip:  0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 200 SCT 250 -SCT 60 342/35/20/1605/054/ THN K LYR NW-N-NNE
WND LGT/ 8/009 50003

1 P.M.
Weather: Clear, few altocumulus distant S-W-NNW,
few cirrocumulus all quadrants, few cirrus all quadrants
Temperature: 40F; Dew Point: 25F; Relative Humidity: 53%
Wind: S @ 8 kts
Sea-level pressure: 1032.3 mb; 30.48 in. Hg: falling, then more rapidly
Visibility: 40 miles
6-hr Max temp: 41F
6-hr Min temp: 29F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 CLR 40 323/40/25/1908/048/ FEW AC DSNT S-W-NNW FEW CC ALQDS
FEW CI ALQDS/ 8/059 58019 10041 20029

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SUMMARY FOR FRIDAY, DECEMBER 22, 2023

TEMPERATURE (DEGREES F)
MAX…….34   NORMAL…..39
MIN…….16   NORMAL…..23
MEAN……25   NORMAL…..31

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………..-6
TOTAL DEPARTURE FOR THE MONTH…………………+100 [+4.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY……………40  DEPARTURE……..+6
TOTAL HEATING UNITS FOR THE MONTH…………..587  DEPARTURE……-101
TOTAL HEATING UNITS FOR THE SEASON…………1674  DEPARTURE……-217
TOTAL HEATING UNITS LAST SEASON TO DATE…….1616  DEPARTURE…….+58

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)……….E18 NNW  @  01:40 A.M.
VECTOR #1 (1-Sec)……….18 NNW  @  12:41 A.M.
VECTOR #2 (1-Sec)……….20 NNW  @  12:13 A.M.
DAVIS #1……………….17 NNW  @  12:41 A.M.
DAVIS #2 ………………18 NNW  @  12:13 A.M.
RMY #1 (Instantaneous)…..19 NNW  @  01:40 A.M.
RMY #2 (Instantaneous)…..20 NNW  @  12:13 A.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)……19      @  01:40 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………12 NNW  @  12:22 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..12      @  12:41 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..13      @  12:15 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………13 NNW  @  12:00 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………13 N    @  12:42 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..12 NNW  @  08:51 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..13 NNW  @  12:42 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………13      @  12:19 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…….5.1 NNW [123 total miles] VECTOR #1……………..6.0
VECTOR #2……………..6.1
DAVIS #1………………5.5 NNW
DAVIS #2………………5.4 N
RMY #1………………..5.8 NNW
RMY #2………………..6.0 NNW
RICHARDS (C5C)…………6.6

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.18
TOTAL PRECIPITATION FOR THE MONTH…………..6.44 DEPARTURE…..+2.52
TOTAL PRECIPITATION FOR THE YEAR…………..57.81 DEPARTURE…..+5.42

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE……-0.4
TOTAL SNOWFALL FOR THE MONTH………………..0.3 DEPARTURE……-7.7
TOTAL SNOWFALL FOR THE SEASON (2023-2024)…….0.3 DEPARTURE…..-10.2

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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  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 34/20/27/-4/0.00/0.0/534/98         29 NNW VEC1 30 NNW RMY 28
12/22 34/16/25/-6/0.00/0.0/…/..         18 NNW VEC1 18 NNW RMY 19

12/23 The low since midnight is 26F, the daily normal low is 23F

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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 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

RECORDS FOR DECEMBER 24
HIGH 67 IN 2015
LOW -6 IN 1943
PRECIP 2.21 INS. IN 1994
SNOWFALL 12.3 INS. IN 1961
PEAK GUST 79e MPH SE IN 1941

TODAY’S REPORT PREPARED BY: Joshua Polen