Sunday, December 23, 2018

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, DECEMBER 23, 2018
ALL TIMES ARE IN EASTERN STANDARD TIME

A RETURN TO HIGH PRESSURE AND SEASONAL TEMPERATURES…

Along with the return to westerly airflow, rising pressure and
clearing skies have yielded a return to seasonal temperatures.
Winds have slowly diminished since yesterday, registering only 10 kts
at 1 P.M., but not before bringing in relatively colder air and
seeing temperatures floating around seasonal expectations.  High
pressure appears to have crested before noon today, with
the mercury beginning to drop slowly by the time of the 1 P.M.
observation.  Visibility has sustained at 80 miles for the past
2 observations, and with cloud activity at a minimum, this has
produced a blue bird day over the blue hills.

Today’s Observations:

7 A.M.
Weather: Few cirrocumulus, few distant stratocumulus SE-NE,
few distant altocumulus N
Temperature: 27F; Dew Point: 20F; Wind: WNW at 12G18 kts
Sea-level pressure: 30.04 ins. Hg, rising steadily
Visibility: 70 miles
6-hr Max temp: 31F
6-hr Min temp: 27F
24-hr Precip: 0.02 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 CLR 70 171/27/20/2912G18/004/
FEW CC FEW DSNT SC SE-NE FEW DSNT AC N/ 8/499/ 52031 10031 20027

10 A.M.
Weather: Few distant cumulus NE S-SE SW
Temperature: 32F; Dew Point: 15F; Wind: WNW at 15G24 kts
Sea-level pressure: 30.08 ins. Hg, increasing, then more slowly
Visibility: 80 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 80 187/32/15/2915G24/008/
FEW DSNT CU NE S-SE SW/ 8/100/ 51016

1 P.M.
Weather: Clear sky
Temperature: 37F; Dew Point: 21F; Wind: W at 10G21 kts
Sea-level pressure: 30.04 ins. Hg, decreasing, then steady
Visibility: 80 miles
6-hr Max temp: 38F
6-hr Min temp: 27F
6-hr Precip: 0.00 ins.
6-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1755 CLR 80 174/37/21/2810G21/004/ 8/000/ 56013 10038 20027

SUMMARY FOR SATURDAY, DECEMBER 22, 2018

TEMPERATURE (DEGREES F)
MAX…..54   NORMAL…..37
MIN…..31   NORMAL…..22
MEAN….43   NORMAL…..29

DEPARTURE FROM 30-YEAR NORMAL…………………..+14
TOTAL DEPARTURE FOR THE MONTH…………………..+17 [+0.6 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..22   DEPARTURE……..-14
TOTAL HEATING UNITS FOR THE MONTH………….690   DEPARTURE……..-19
TOTAL HEATING UNITS FOR THE SEASON………..1971   DEPARTURE……..+39
TOTAL HEATING UNITS LAST SEASON TO DATE……1683   DIFFERENCE……+327

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..41 W   AT 2:02  P.M.
AERO…………………….45 W   AT 2:00  P.M.
ASOS…………………….44 W   AT 2:07  P.M.
DAVIS……………………45 W   AT 2:06  P.M. RMY 43
FASTEST MILE FOR YESTERDAY………………….31 W   AT 4:50  P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….30 W   AT 4:24  P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………33 W   AT 2:45  P.M.
AVERAGE WIND SPEED AND DIRECTION…………..20.2 W
ASOS…………………..19.4
DAVIS………………….19.9 SSE [256 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.02  DEPARTURE…….-0.14
ASOS…………..0.02
TOTAL PRECIPITATION FOR THE MONTH……….3.12  DEPARTURE…….-0.43
ASOS…………..3.76 *
TOTAL PRECIPITATION FOR THE YEAR……….66.49  DEPARTURE……+14.60
ASOS………….69.39 *
* ASOS MONTHLY AND ANNUAL PRECIPITATION IS SUSPECT

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..-0.5
TOTAL SNOWFALL FOR THE MONTH…………….0.1  DEPARTURE……..-8.6
TOTAL SNOWFALL FOR THE SEASON……………7.7  DEPARTURE……..-3.6

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 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

12/01 41/28/35/-2/0.00/0.0/391/70          20 NNW AERO 18 NNW RMY N/A
12/02 52/35/44/+8/1.04/0.0/000/00          28 ESE AERO 25 ESE RMY 27
12/03 54/38/46/+10/0.00/0.0/178/32         35 W   AERO 35 W   RMY 38
12/04 38/23/31/-4/0.00/0.0/516/93          30 WNW AERO 31 WNW RMY 33
12/05 33/18/26/-9/0.00/0.0/432/78          16 NNW AERO 15 NNW RMY N/A
12/06 37/24/31/-4/0.00/0.0/354/64          29 W   AERO 28 W   RMY 30
12/07 37/21/29/-5/0.00/0.0/…/..          29 NW  AERO 29 NW  RMY 32
12/08 27/15/21/-13/0.00/0.0/…/..         28 NW  AERO 27 NW  RMY 29
12/09 34/17/26/-8/0.00/0.0/…/..          23 SSW AERO 21 SSW RMY 22
12/10 36/22/29/-4/0.00/0.0/…/..          24 NNW AERO 23 NNW RMY 22
12/11 36/17/27/-6/0.00/0.0/…/..          16 WSW AERO 14 WSW RMY N/A
12/12 35/18/27/-6/0.00/0.0/…/..          30 NW  AERO 29 NW  RMY M
12/13 31/16/24/-8/0.00/0.0/…/..          16 NNE AERO 12 SE  RMY N/A
12/14 46/28/37/+5/0.00/0.0/…/..          28 SSW AERO 28 SSW RMY 29
12/15 49/33/43/+11/0.04/0.0/…/..         28 NE  AERO 27 NE  RMY 30
12/16 40/37/39/+8/…./0.0/…/..          38 NE  AERO 38 NE  RMY 40
12/17 37/32/35/+4/…./0.0/…/..          39 NNE AERO 37 NNE RMY N/A
12/18 34/20/27/-4/0.02/0.1/…/..          48 NW  AERO 55 NW  RMY 48
12/19 38/17/28/-2/0.00/0.0/…/..          23 WNW AERO 23 WNW RMY N/A
12/20 47/30/39/9/0.00/0.0/…/..           23 SW  AERO 22 SW  RMY N/A
12/21 62/43/53/+23/…./0.0/…/..         60 SSE AERO 62 SSE RMY 63
12/22 54/31/43/+14/…./0.0/…/..         41 W   AERO 45 W   RMY 43

12/23 Low temp since midnight is 27F; normal low is 21F

DAILY RECORDS FOR DECEMBER 2018

12/21/18: DAILY RECORD HIGH MAXIMUM TEMPERATURE OF 62F,
BREAKS PREVIOUS RECORD OF 60F SET IN 1957

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 1.70 INS. IN 1947
SNOWFALL 11.9 INS. IN 1947
PEAK GUST 67 SSE IN 2004

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: Nate Iannuccillo