Monday, December 11, 2023

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

MONDAY, DECEMBER 11, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0703E
SUNSET:  1612E

HEAVY RAIN, STRONG WINDS, AND WARM TEMPS OVERNIGHT, TURNING SHARPLY
COOLER HEADING INTO THIS AFTERNOON….

A dynamic storm system brought heavy rain, strong winds, and warm
temperatures (relative to normal) to the region overnight. Rain
began falling shortly after 1pm yesterday afternoon. It was
generally on the light side until mid to late evening when it then
became moderate to heavy. Rainfall continued at this intensity
right into the mid morning hours of today. A total of 2.62″ of
rain was recorded here on the hill. 1.70″ of which fell between
midnight and 7am!

Strong winds were also observed with this storm system with gusts
reaching over 50mph during the late evening hours yesterday, then
peaking with gusts near 70mph (officially 69mph) between 2-3am this
morning. A sharp wind shift from SSW to NW occurred at around 3:30am
as a cold frontal passage took place.

Temperatures rose into the low 60s overnight maxing out at 61F just
before the frontal passage. Once the front passed, the temperature
dropped rapidly from 61F to 45F within about a 30 minute period.
Modest cold air advection has been taking place since late this
morning and readings have dropped to around 40F early this afternoon
on a gusty west-northwest wind.

Even though the rain ended between 9-10am, skies have remained
overcast to this point.

Visibility was very much limited early this morning in the rain
and fog, down under 1 mile at times, but has improved markedly
early this afternoon, up to around 70 miles!

The maximum temperature for today is 61F degrees, occurring around
2:30am, this is 20F above the normal high of 41F. The minimum
temperature since midnight is 40F degrees, this is 14F above the
normal low of 26F.

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Today’s Observations:

7 A.M.
Weather: Sky obscured, vertical visibility 200ft, moderate rain
Temperature: 42F; Dew Point: 42F; Relative Humidity: 100%
Wind: NNW @ 11G17 kts
Sea-level pressure: 998.6 mb; 29.49 in. Hg: rising, then falling
Visibility: 1 mile, fog
6-hr Max temp: 61F
6-hr Min temp: 42F
24-hr Precip:  2.36 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 X W2 1RF 986/42/42/3311G17/949/ 8//// 58010 6153/ 70232
10061 20042

10 A.M.
Weather: Overcast stratus, few lower stratus fractus N-NE
Temperature: 42F; Dew Point: 42F; Relative Humidity: 100%
Wind: WNW @ 14G25 kts, peak wind WNW 31 mph (27 kts) at 9:41 A.M.
Sea-level pressure: 999.7 mb; 29.52 in. Hg: falling, then rising
Visibility: 50 miles
3-hr Precip:  0.26 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 E3 OVC 50 997/42/42/3014G25/952/ FEW LWR STFRA N-NE R-E23
PK WND 2927/41/ 8/7// 53011 6026/

1 P.M.
Weather: Overcast altostratus, few breaks in overcast distant SSW-NW and
distant E-ESE, virga distant S-SSW
Temperature: 40F; Dew Point: 35F; Relative Humidity: 83%
Wind: WNW @ 17G33 kts, peak wind WNW 39 mph (34 kts) at 12:40 P.M.
Sea-level pressure: 1003.7 mb; 29.64 in. Hg: rising, then more rapidly
Visibility: 70 miles
6-hr Max temp: 43F
6-hr Min temp: 40F
6-hr Precip:  0.26 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 E45 OVC 70 037/40/35/3017G33/964/ FEW BINOVC DSNT SSW-NW AND
DSNT E-ESE VIRGA DSNT S-SSW PK WND 3034/40/ 8/52/ 53040 6026/ 10043 20040

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SUMMARY FOR SUNDAY, DECEMBER 10, 2023

TEMPERATURE (DEGREES F)
MAX…….60   NORMAL…..42
MIN…….43   NORMAL…..27
MEAN……52   NORMAL…..34

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……….+18
TOTAL DEPARTURE FOR THE MONTH………………….+34 [+3.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY……………13  DEPARTURE…….-18
TOTAL HEATING UNITS FOR THE MONTH…………..261  DEPARTURE…….-34
TOTAL HEATING UNITS FOR THE SEASON…………1348  DEPARTURE……-151
TOTAL HEATING UNITS LAST SEASON TO DATE…….1220  DEPARTURE……+128

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)……….E55 SSW  @  11:52 P.M.
VECTOR #1 (1-Sec)……….54 SSW  @  11:52 P.M.
VECTOR #2 (1-Sec)……….56 SSW  @  11:59 P.M.
DAVIS #1……………….59 S    @  11:46 P.M.
DAVIS #2 ………………60 S    @  10:55 P.M.
RMY #1 (Instantaneous)…..53 S    @  11:20 P.M.
RMY #2 (Instantaneous)…..57 SSW  @  11:59 P.M.
MERLIN…………………M
RICHARDS (C5C) (Inst)……51      @  11:13 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………41 S    @  11:21 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..37      @  11:21 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..39      @  11:39 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………37 S    @  11:39 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………42 S    @  11:46 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..36 S    @  11:21 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..39 SSW  @  11:39 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………36      @  11:21 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL…….18.5 SSW [445 total miles] VECTOR #1……………..18.4
VECTOR #2……………..19.1
DAVIS #1………………18.0 S
DAVIS #2………………19.7 SSW
RMY #1………………..18.0 SSW
RMY #2………………..19.3 SSW
RICHARDS (C5C)…………17.9

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..2.36 DEPARTURE…..+2.18
TOTAL PRECIPITATION FOR THE MONTH…………..3.24 DEPARTURE…..+1.45
TOTAL PRECIPITATION FOR THE YEAR…………..54.61 DEPARTURE…..+4.35

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE……-0.3
TOTAL SNOWFALL FOR THE MONTH………………..0.3 DEPARTURE……-2.6
TOTAL SNOWFALL FOR THE SEASON (2023-2024)…….0.3 DEPARTURE……-5.1

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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  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/…/..        18 NNW VEC1 18 NW  RMY 19
12/8  42/24/33/-2/0.00/0.0/…/..         20 S   VEC1 18 S   RMY 18
12/9  52/33/43/+9/0.00/0.0/…/..         24 S   VEC1 24 S   RMY 24
12/10 60/43/52/+18/0.66/0.0/…/..        55 SSW VEC1 54 SSW RMY 53

12/11 The low since midnight is 40F, the daily normal low is 26F

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DECEMBER DAILY RECORDS TO DATE

NONE…

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

RECORDS FOR DECEMBER 11
HIGH 63 IN 1911
LOW -1 IN 1988
PRECIP 2.36 INS. IN 1992
SNOWFALL 4.8 INS. IN 2019
PEAK GUST 78 S IN 1969

RECORDS FOR DECEMBER 12
HIGH 67 IN 1979
LOW -3 IN 1988
PRECIP 3.94 INS. IN 1992
SNOWFALL 20.3 INS. IN 1960
PEAK GUST 75 MPH SSE IN 2008

TODAY’S REPORT PREPARED BY: Matt Douglas