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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 15, 2012
ALL TIMES ARE IN EASTERN STANDARD TIME

ANOTHER VERY SUNNY MID-DECEMBER DAY

The sky has been almost completely clear for much of the day with 
a few distant stratocumulus offshore and a few cirrus briefly 
obscuring the sun for a few minutes following sunrise shortly 
after 7 AM. The low temperature of 31 was much warmer than the 
average minimum in the mid-20s, and the high temperature has
reached the average high of 40 as of early afternoon, so this
will be another warmer than average day.  Visibility was in 
the 40-45 mile range earlier has climbed to 75 miles by mid-day,
with the dew point temperature dropping to the lower 20s 
by early afternoon. 


Today's observations:
 
7 A.M.
Weather: Clear, few stratocumulus distant NNE-SE, few stratocumulus
castellanus ENE-E, few cirrus distant E-NW, hazy
Temperature: 31F; Dew Point: 25F; Wind: NW at 13 kts.
Sea-level pressure: 30.26 ins Hg, rising then rising more slowly 
Visibility: 45 miles, hazy
6-hour min. temp: 31F
BHO SA 1155 CLR 45 247/31/25/3213/026/ FEW SC DSNT NNE-SE FEW 
SCCAS ENE-E FEW CI DSNT E-NW HAZY/ 8/501 51017 10032 20031 

10 A.M.
Weather: Clear, few stratocumulus distant NE-SSE, few cirrus
distant SE-W, few patches dense cirrus S-WSW, light distant haze
Temperature: 36F; Dew Point: 31F; Wind: NNW at 10 kts,
Wind: Direction variable NW-N
Sea-level pressure: 30.32 ins Hg, rising     
Visibility: 75 miles, light distant haze
BHO SA 1455 CLR 75 269/36/31/3410/032/ FEW SC DSNT NE-SSE FEW CI 
DSNT SE-W FEW PTCHS DNS CI S-WSW LGT DSNT HZ WND 31V01/ 8/501 51022

1 P.M.
Weather: Thin scattered cirrus, few stratocumulus NNE-SSE, few
lower dense cirrus S-SE
Temperature: 39F; Dew Point: 22F; Wind: NNE at 4 kts,
Wind: Light and variable
Sea-level pressure: 30.29 ins Hg, falling  
Visibility: 75 miles
6-hour max. temp: 40F
BHO SA 1755 250 –SCT 75 259/39/22/0304/029/ FEW SC NNE-SSE FEW LWR 
DNS CI S-SE WND LGT AND VRB/ 8/501 58010 10040 20031


WEATHER SUMMARY FOR FRIDAY, DECEMBER 14

TEMPERATURE (DEGREES F)
MAX.....47      NORMAL.....40
MIN.....29      NORMAL.....24
MEAN....38      NORMAL.....32
 
DEPARTURE FROM 30-YEAR NORMAL.....................+6
TOTAL DEPARTURE FOR THE MONTH....................+85 [+5.9 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............27    DEPARTURE.........-6
TOTAL HEATING UNITS FOR THE MONTH...........346    DEPARTURE........-85  
TOTAL HEATING UNITS FOR THE SEASON.........1496    DEPARTURE.......-197
TOTAL HEATING UNITS LAST SEASON TO DATE....1245    DIFFERENCE......+251

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...............28 W   AT  3:49 P.M.
                   AERO....................25 W   AT  3:59 P.M. 
                   ASOS....................26 W   AT  3:50 P.M.
                   DAVIS...................27 WSW AT  3:49 P.M. RMY 27 
THE FASTEST MILE FOR YESTERDAY.............18 W   AT  3:59 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE..............18 W   AT  3:35 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.............16 W   AT  3:34 P.M.
AVERAGE WIND SPEED AND DIRECTION.........12.4 WNW	
                   ASOS..................11.7 
                   DAVIS.................10.2 W [267 deg.]
* last of several occurrences....
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00   DEPARTURE..........-0.16
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........1.11   DEPARTURE..........-1.03
                         ASOS..............1.13
TOTAL PRECIPITATION FOR THE YEAR..........35.99   DEPARTURE.........-14.68
                         ASOS.............36.02

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........0.0    DEPARTURE..........-0.4
TOTAL SNOWFALL FOR THE MONTH...............0.8    DEPARTURE..........-4.1
TOTAL SNOWFALL FOR THE SEASON..............6.8    DEPARTURE..........-0.7	

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/.../..     20 NW  AERO 18 MPH NW  RMY N/A
12/13 42/29/36/+4/0.00/0.0/.../..     18 NW  AERO 15 MPH NW  RMY N/A
12/14 47/29/38/+6/0.00/0.0/.../..     28 W   AERO 25 MPH W   RMY 27
  
12/15 morning low temp: 31F; the normal low is now 24F

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 15
HIGH 64 IN 1975
LOW 4 IN 1900, 1905, 1933
PRE 1.80 INS. IN 1981
SNOW 7.5 INS. IN 1951
PEAK GUST 65 MPH NW IN 1991

RECORDS FOR DECEMBER 16
HIGH 61 IN 1971
LOW -2 IN 1930
PRE 1.67 INS. IN 1960
SNOW 8.5 INS. IN 2007
WIND 73 MPH SSE IN 1982

TODAY'S REPORT PREPARED BY: Mike Iacono