Monday, December 11, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, DECEMBER 11, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

SKY CLEARS AFTER QUICK MORNING SNOW SHOWER…

A quick moving light snow shower moved over Great
Blue Hill this morning just before 8:00 AM.
Since it was quick moving this shower did not
accumulate any measurable snow on the hill.
The morning began with overcast altostratus
clouds, but the sky cleared throughout the day
to scattered cumulus by 1:00 PM. Even though
we had lower humidity and dew points today
visibility was limited due to a distant haze
with a maximum of 55 miles by 1:00 PM.
Temperatures have been slightly below seasonable
for maximum high temperatures. Yesterday’s max
of 35F was 6 degrees below the normal of 41F.
Minimum temperatures have been closer to normal
with a low temperatures of 27F which is only 1
degree above the normal of 26F.

Today’s Observations:

7 A.M.
Weather: Overcast altostratus, few altocumulus overhead
Temperature: 30F; Dew Point: 21F; Wind: SW at 11 kts
Sea-level pressure: 29.97 ins. Hg, rising unsteadily
Visibility: 40 miles, distant fog in all directions
6-hr Max temp: 30F
6-hr Min temp: 29F
24-hr precip: 0.00 ins.
24-hr snowfall: 0.0 ins.
Snow cover: 3 ins.
BHO SA 1155 E65 OVC 40 148/30/21/2211/997/ FEW AC OVHD DSNT
FG ALQDS/ 8/020 4/003 52010 10030 20029

10 A.M.
Weather: Broken altocumulus
Temperature: 32F; Dew Point: 22F; Wind: WSW at 7 kts
Sea-level pressure: 29.99 ins. Hg, rising, then more slowly
Visibility: 50 miles, distant haze in all directions
3-hr precip: Trace
3-hr snowfall: Trace
BHO SA 1455 E90 BKN 50 156/32/22/2407/999/ NEW SNW PST 3 HRS
TRACE DSNT HZ/ 8/030 51008 MANUAL 600//

1 P.M.
Weather: Scattered cumulus
Temperature: 34F; Dew Point: 24F; Wind: W at 13G20 kts
Sea-level pressure: 29.96 ins. Hg, falling, then more quickly
Visibility: 55 miles, distant haze in all directions
6-hr Max temp: 37F
6-hr Min temp: 29F
6-hr precip: Trace
6-hr snowfall: Trace
BHO SA 1755 30 SCT 55 146/34/24/2713G20/996/ NEW SNW PST 6 HRS
TRACE DSNT HZ/ 8/100 4/002 56010 MANUAL 600// 10037 20029

SUMMARY FOR SUNDAY, DECEMBER 10, 2017

TEMPERATURE (DEGREES F)
MAX…..35   NORMAL…..41
MIN…..27   NORMAL…..26
MEAN….31   NORMAL…..33

DEPARTURE FROM 30-YEAR NORMAL………………………-2
TOTAL DEPARTURE FOR THE MONTH……………………..+27 [+2.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….34  DEPARTURE……….+2
TOTAL HEATING UNITS FOR THE MONTH…………274  DEPARTURE………-27
TOTAL HEATING UNITS FOR THE SEASON……….1243  DEPARTURE……..-319
TOTAL HEATING UNITS LAST SEASON TO DATE…..1331  DIFFERENCE……..-88

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….30 W   AT 2:28 P.M.
AERO……………………30 W   AT 2:26 P.M.
ASOS……………………30 W   AT 2:29 P.M.
DAVIS…………………..29 WNW AT 2:28 P.M. RMY 27
FASTEST MILE FOR YESTERDAY…………………21 W   AT 2:28 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………22 W   AT 2:59 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..21 W   AT 2:59 P.M.
AVERAGE WIND SPEED AND DIRECTION………….11.9 W
ASOS………………….12.3
DAVIS…………………11.2 W  [271 DEG.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.17
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….1.48  DEPARTURE……-0.17
ASOS…………..1.57
TOTAL PRECIPITATION FOR THE YEAR……….51.32  DEPARTURE……+1.14
ASOS……………N/A **
** ASOS annual total not available due to erroneous readings

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.4
TOTAL SNOWFALL FOR THE MONTH…………….5.6  DEPARTURE…….+2.4
TOTAL SNOWFALL FOR THE SEASON……………5.6  DEPARTURE…….-0.2

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 50/35/43/+6/0.04/…/..          28 NW  AERO 29 NW  RMY 30
12/02 42/29/36/0/0.00/…/..           20 NNW AERO 18 NNW RMY N/A
12/03 42/32/37/+1/0.00/…/..          14 N   AERO 10 N   RMY N/A
12/04 43/32/38/+3/0.00/…/..          16 E   AERO 14 E   RMY N/A
12/05 58/34/46/+11/…/…/..          62 S   AERO 66 S   RMY 65
12/06 56/32/44/+9/…/…/..           52 S   AERO 55 S   RMY N/A
12/07 44/30/37/+3/0.00/…/..          25 WSW AERO 24 WSW RMY 25
12/08 38/28/33/-1/0.00/…/..          21 W   AERO 18 W   RMY 20
12/09 34/28/31/-3./…./…/..         23 NNW AERO 23 NNW RMY 23
12/10 35/27/31/-2/…./…/..          30 W   AERO 30 W   RMY 27

12/11 Low temp since midnight is 29F; normal low is now 25F

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 6.0 INS. IN 1894
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: Kaitlin Geagan