Thursday, January 21, 2021

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

THURSDAY, JANUARY 21, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0707E
SUNSET:  1645E

INCREASING CLOUDS WITH A PERIOD OF LIGHT SNOW EARLY THIS
AFTERNOON….

We started the day with a mix of sun and clouds. Visibility
was decent ranging from 50 to 60 miles. However the clouds
took over with a band of light snow moving into the area
early this afternoon. So far snow has only amounted to a
coating, we’ll see if we can squeeze out anything measurable.

Today is definitely noticeably colder with the low temperature
this morning finally dropping below 20 for the first time this
month. With a steady southerly breeze, it feels rather cold
out there today as the mercury hasn’t reached 30 degrees!

The stretch of above normal temperatures is likely complete.
Yesterday marked the 31st consecutive day of above normal
temperatures, stretching back to December 21st! Today will
likely end up being below normal for the first time since
December 19th.

The high temperature so far today is 29F, this is 5 degrees
below the daily normal maximum of 34F. The low since midnight
is 17F, which equals the normal minimum of 17F.

Today’s Observations:

7 A.M.
Weather: Broken altocumulus, broken cirrus, thin broken cirrus,
few stratocumulus offshore distant NE-SE
Temperature: 18F; Dew Point: 7F; Relative Humidity: 62%
Wind: SSW @ 5 kts, wind light
Sea-level pressure: 29.87 in Hg; falling, then more rapidly
Visibility: 50 miles
6-hr Max temp: 20F
6-hr Min temp: 18F
24-hr Precip: Trace.
24-hr Snow: Trace.
Snow Depth: 0 ins.
BHO SA 1155 E130 BKN 180 BKN 250 -BKN 50 116/18/7/2005/987/ FEW SC OFFSHR DSNT NE-SE WND LGT/ 8/571 58012 70000 10020 20018

10 A.M.
Weather: Overcast altocumulus, few breaks in overcast distant SSE-S,
few stratocumulus offshore distant NNE-ESE and distant SSE-SSW, few
lower altostratus distant SSW-NW, virga distant NW-NE
Temperature: 24F; Dew Point: 10F; Relative Humidity: 55%
Wind: S @ 6 kts
Sea-level pressure: 29.82 in Hg; falling, then more rapidly
Visibility: 60 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 E140 OVC 60 099/24/10/1906/982/ FEW BINOVC DSNT SSE-S FEW SC OFFSHR DSNT NNE-ESE AND DSNT SSE-SSW FEW LWR AS DSNT SSW-NW VIRGA DSNT NW-NE/ 8/57/ 58017

1 P.M.
Weather: Scattered stratus fractus, overcast nimbostratus, light snow
Temperature: 28F, Dew point: 16F; Relative Humidity: 60%
Wind: SSW @ 10G17 kts
Sea-level pressure: 29.72 inches Hg, falling, then more rapidly
Visibility: 5 miles, 10 miles E
6-hr Max temp: 29F
6-hr Min temp: 17F
6-hr Precip: Trace.
6-hr Snow: Trace.
Snow Depth: 0 ins.
BHO SA 1755 35 SCT E44 OVC 5S-F 063/28/16/2010G17/972/ VSBY 10 E SUN DMLY VSBL S-B35/ 8/7// 58036 6000/ 10029 20017

SUMMARY FOR WEDNESDAY, JANUARY 20, 2021

TEMPERATURE (DEGREES F)
MAX…….37   NORMAL…..33
MIN…….22   NORMAL…..17
MEAN……30   NORMAL…..25

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….  +5
TOTAL DEPARTURE FOR THE MONTH……………….+149 [+7.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………35  DEPARTURE…..  -5
TOTAL HEATING UNITS FOR THE MONTH…………..640  DEPARTURE…..-148
TOTAL HEATING UNITS FOR THE SEASON…………2570  DEPARTURE…..-523
TOTAL HEATING UNITS LAST SEASON TO DATE…….2876  DEPARTURE…..-306

PEAK WIND GUST (MPH):
420C/Official…………..32 WNW @  4:56 P.M.
AEROVANE (south tower)…..33 WNW @  4:59 P.M.
ASOS…………………..32 WNW @  4:56 P.M.
DAVIS #1……………….32 WNW @  4:51 P.M.
DAVIS #2 (south tower)…..35 NW  @  3:22 P.M.
RMY……………………34     @  3:55 P.M.
VECTOR…………………36     @  3:55 P.M.
MERLIN…………………33

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………23 WNW @  4:53 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….21 NW  @  5:00 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………23 WNW @  4:56 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………25 WNW @  4:55 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..21 NNW @  3:21 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..21     @  4:54 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL… 9.9 WNW [237 total miles] ASOS……………… 9.7     [233 total miles] DAVIS #1…………..10.4 WNW [250 total miles] DAVIS #2…………..10.7 WNW [257 total miles] RMY………………. 9.5 WNW [228 total miles] VECTOR…………….10.1     [242 total miles]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……TRACE  DEPARTURE….-0.14
ASOS………….1.06
TOTAL PRECIPITATION FOR THE MONTH………….1.94  DEPARTURE….-0.90
ASOS………….2.00
TOTAL PRECIPITATION FOR THE YEAR…………..1.94  DEPARTURE….-0.90
ASOS…………2.00

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0  DEPARTURE…..-0.5
TOTAL SNOWFALL FOR THE MONTH……………… 1.9  DEPARTURE…..-9.3
TOTAL SNOWFALL FOR THE SEASON……………..28.1  DEPARTURE…..+0.9

PRELIMINARY CLIMATE SUMMARY FOR JANUARY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system gust
RMY:  R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

01/01   36/25/31/+4/0.06/0.3/330/60       23 E    AERO 23 NNW  RMY 23
01/02   43/30/37/+10/0.30/T/116/21        37 WNW  AERO 39 WNW  RMY 44
01/03   33/27/30/+4/0.07/0.8/000/00       23 NNE  AERO 22 NNE  RMY 25
01/04   37/28/33/+7/0.01/0.1/110/20       25 NNE  AERO 23 NNE  RMY 27
01/05   31/28/30/+4/0.05/0.7/000/00       21 NNW  AERO 21 NNW  RMY 22
01/06   38/28/33/+7/T/T/244/44            30 NW   AERO 29 NW   RMY 32
01/07   42/26/34/+8/0.00/0.0/516/93       28 NNW  AERO 26 NNW  RMY 31
01/08   40/21/31/+5/0.00/0.0/517/93       25 NNW  AERO 22 NNW  RMY 25
01/09   34/30/27/+1/0.00/0.0/395/71       25 N    AERO 23 N    RMY 24
01/10   39/24/32/+7/0.00/0.0/493/88       25 NNW  AERO 23 NNW  RMY 24
01/11   34/25/30/+5/0.00/0.0/000/00       17 SW   AERO 16 SSW  RMY 16
01/12   40/24/32/+7/0.00/0.0/438/78       23 WNW  AERO 23 WNW  RMY 24
01/13   40/26/33/+8/0.00/0.0/389/69       15 SW   AERO 14 SW   RMY 19
01/14   38/31/35/+10/0.09/T/000/00        16 SSW  AERO 16 SSW  RMY 19
01/15   40/32/36/+11/0.00/0.0/266/47      25 ESE  AERO 23 ESE  RMY 27 TSTM
01/16   52/33/43/+18/1.00/0.0/000/00      48 ESE  AERO 53 SE   RMY 54
01/17   41/32/37/+12/0.00/0.0/314/55      47 W    AERO 46 W    RMY 54
01/18   42/27/35/+10/T/0.0/…/..         35 W    AERO 37 WNW  RMY 36
01/19   39/23/31/+6/T/T/…/..            25 WNW  AERO 25 WNW  RMY 27
01/20   37/22/30/+5/T/T/…/..            32 WNW  AERO 33 WNW  RMY 34

01/21 The low since midnight is 17F, the daily normal low is 17F

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

RECORDS FOR JANUARY 21
HIGH 65F IN 1906
LOW -4F IN 1888,1893
PRECIP 2.49 INS. IN 1979
SNOWFALL 9.0 INS. IN 2014
PEAK GUST 78e MPH SE IN 1979

RECORDS FOR JANUARY 22
HIGH 59F IN 1916
LOW -8F IN 1888,1976
PRECIP 1.24 INS. IN 1891,1987
SNOWFALL 10.0 INS. IN 2005
PEAK GUST 67 MPH W IN 1976

TODAY’S REPORT PREPARED BY: Matt Douglas