BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, DECEMBER 26, 2012
ALL TIMES ARE IN EASTERN STANDARD TIME
 
CALM AND COOL AHEAD OF APPROACHING STORM SYSTEM
 
After picking up just over half an inch of snow on Christmas, quiet conditions
returned to the summit today.  Temperatures have been quite cool, and our low
temperature of 20F this morning is our coldest of the season so far by 5
degrees.  We are on track for our first below normal day since December 12
as the month continues to run 6 degrees above normal. These cool temperatures
have allowed much of yesterday's light snow to remain on the ground.  The
temperature has climbed but so far we remain well below our normal of 37F.
 
Winds were unusually calm yesterday, and that has continued into today with
a peak wind gust of just 16mph recorded so far since 7AM this morning.
Winds are expected to increase this afternoon and tonight as a powerful
storm prepares to bring heavy rain, high winds, and heavy snow farther inland.
The barometer has started dropping and this should continue into tonight. 
 
Today's observations:
 
7 A.M.
Weather: Clear, cumulus and stratocumulus along and offshore distant NE-SSE,
altocumulus and altocumulus lenticularis distant SE-SSW, cirrus distant ENE-
SE-SSW
Temperature: 20F; Dew Point: 13F; Wind: N at 9 kts
Sea-level pressure: 30.26 ins. Hg, decreasing then increasing 
Visibility: 40 miles, distant haze
6-hour min. temp: 20F
24-hour precip: 0.02 inch
24-hour snowfall: 0.4 inch
Snow on ground: Trace
BHO SA 1155 CLR 40 248/20/13/3609/026/ CU/SC ALG/OFFSHR DSNT NE-SSE
AC/ACSL DSNT SE-SSW CI DSNT ENE-SE-SSW TOTAL NEW SNW PST 24 HRS 0.4 IN/
8/841 4/001 55003 MANUAL 70002 ASOS 70003 10024 20020
 
10 A.M.
Weather: Clear, few cumulus and stratocumulus along and offshore ENE-ESE,
few altocumulus lenticularis distant SW-WSW, cirrus E-S-W, cirrus and
cirrostratus layer
Temperature: 27F; Dew Point: 16F; Wind: NNW at 4 kts
Wind: Light
Sea-level pressure: 30.31 ins. Hg, increasing
Visibility: 45 miles, distant haze
BHO SA 1455 CLR 300 –SCT 45 264/27/16/3304/031/FEW CU/SC ALNG/OFFSHR
ENE-ESE FEW ACSL DSNT SW-WSW CI E-S-W CI/CS LYR DSNT S-WSW INVDNG
THN K LYR ABV HRZN W-WNW ALG HRZN NW-NE DSNT HZ WND LGT/ 8/845 51016 
 
1 P.M.
Weather: Broken stratocumulus, overcast dense cirrostratus, few altocumulus
lenticularis NNW-N, break in overcast distant N-E
Temperature: 32F; Dew Point: 26F; Wind: NE at 9 kts
Wind: Direction variable N-E
Sea-level pressure: 30.24 ins Hg, falling then falling more slowly
Visibiity: 40 miles, distant haze
6-hour max: 32F
6-hour min: 20F
BHO SA 1755 E20 BKN 220 OVC 40 242/32/26/0409/024 FEW ACSL DSNT
NNW-N BINOVC DSNT N-E WND 36V09/ 8/547 56022 10032 20020    
 
WEATHER SUMMARY FOR TUESDAY, DECEMBER 25 CHRISTMAS DAY
 
TEMPERATURE (DEGREES F)
MAX.....33      NORMAL.....36
MIN.....25      NORMAL.....21
MEAN....29      NORMAL.....28
 
DEPARTURE FROM 30-YEAR NORMAL......................+1
TOTAL DEPARTURE FOR THE MONTH....................+156 [+6.0 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............36    DEPARTURE.........-1
TOTAL HEATING UNITS FOR THE MONTH...........660    DEPARTURE.......-158
TOTAL HEATING UNITS FOR THE SEASON.........1810    DEPARTURE.......-270
TOTAL HEATING UNITS LAST SEASON TO DATE....1573    DIFFERENCE......+237
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY...............21 NNW AT  9:14  P.M.
                   AERO....................21 NNW AT  9:14  P.M.
                   ASOS....................20 NNW AT  11:47 P.M.
                   DAVIS...................18 NNW AT  9:14  P.M.  RMY: 19 
THE FASTEST MILE FOR YESTERDAY.............16 NW  AT  11:57 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE..............16 NNW AT  11:59 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE.............14 NW  AT  11:59 P.M.
AVERAGE WIND SPEED AND DIRECTION.........8.8 NNW
                   ASOS..................9.2
                   DAVIS.................8.1 NNW [342 deg.]
*...last of several occurences
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.02   DEPARTURE..........-0.14
                         ASOS..............0.03
TOTAL PRECIPITATION FOR THE MONTH..........3.56   DEPARTURE..........-0.46
                         ASOS..............3.60
TOTAL PRECIPITATION FOR THE YEAR..........38.44   DEPARTURE.........-14.11
                         ASOS.............38.49
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........0.4    DEPARTURE..........-0.1
TOTAL SNOWFALL FOR THE MONTH...............1.7    DEPARTURE..........-8.5
TOTAL SNOWFALL FOR THE SEASON..............7.7    DEPARTURE..........-5.1    
 
PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2012 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
RMY:  RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
12/1  34/25/30/-7/0.08/0.8/000/00     16 E   AERO 14 MPH E   RMY 16
12/2  52/32/42/+6/0.00/0.0/006/01     32 SSW AERO 32 MPH SSW RMY 34
12/3  57/43/50/+14/0.00/0.0/523/94    31 NW  AERO 30 MPH NW  RMY 32
12/4  56/40/48/+13/0.03/0.0/000/00    37 S   AERO 39 MPH S   RMY 38
12/5  56/31/44/+9/0.03/0.0/310/56     38 WNW AERO 37 MPH WNW RMY 40
12/6  38/25/32/-3/0.00/0.0/519/94     31 NW  AERO 30 MPH NW  RMY N/A
12/7  42/30/36/+2/0.02/0.0/000/00     18 SSW AERO 16 MPH SSW RMY 18       
12/8  45/41/43/+9/0.35/0.0/000/00     21 ENE AERO 18 MPH ENE RMY N/A
12/9  45/38/42/+8/0.10/0.0/181/33     24 NNW AERO 24 MPH NNW RMY 25
12/10 59/39/49/+16/0.51/0.0/000/00    32 SSW AERO 33 MPH SSW RMY 35
12/11 54/30/42/+9/0.01/0.0/351/64     25 W   AERO 25 MPH W   RMY 23
12/12 38/26/32/-1/0.00/0.0/126/23     20 NW  AERO 18 MPH NW  RMY N/A
12/13 42/29/36/+4/0.00/0.0/416/76     18 NW  AERO 15 MPH NW  RMY N/A
12/14 47/29/38/+6/0.00/0.0/535/98     28 W   AERO 25 MPH W   RMY 27
12/15 40/31/36/+4/0.00/0.0/530/97     24 NNW AERO 22 MPH NNW RMY 21
12/16 36/31/34/+3/0.25/0.1/000/00     25 E   AERO 22 MPH E   RMY N/A
12/17 44/36/40/+9/0.65/0.0/000/00     31 ENE AERO 29 MPH ENE RMY 30
12/18 50/40/45/+14/0.61/0.0/000/00    28 E   AERO 24 MPH E   RMY N/A
12/19 44/35/40/+10/T/0.0/087/16       42 WNW AERO 40 MPN WNW RMY 43
12/20 42/30/36/+6/T/0.0/262/48        25 NNW AERO 23 MPH NNW RMY N/A
12/21 53/35/44/+14/0.00/0.0/000/00    58 E   AERO 53 MPH E   RMY 57
12/22 37/26/32/+3/T/T/136/25          47 W   AERO 47 MPH W   RMY 43
12/23 37/25/31/+2/0.00/0.0/305/56     44 WNW AERO 44 MPH WNW RMY N/A
12/24 39/28/34/+5/0.01/0.2/452/83     25 W   AERO 23 MPH W   RMY 22
12/25 33/25/29/+1/0.02/0.4/000/00     21 NNW AERO 21 MPH NNW RMY 19 
 
12/26 morning low temp: 20F; the normal low is now 2OF
 
DAILY RECORDS FOR DECEMBER 2012
None so far.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR DECEMBER 26
HIGH 58 IN 1973,1982
LOW -12 IN 1980
PRECIP 3.64 INS. IN 1969
SNOWFALL 17.5 INS. IN 1909
PEAK GUST 84 MPH SSE IN 1957
 
RECORDS FOR DECEMBER 27
HIGH 57 IN 1895,1949
LOW -4 IN 1903
PRECIP 2.43 INS. IN 1969
SNOWFALL 11.2 INS. IN 1947
PEAK GUST 73 S IN 2011
 
TODAY'S REPORT PREPARED BY: Robert Skilling, Jonathan O'Brien