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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, DECEMBER 20, 2012
ALL TIMES ARE IN EASTERN STANDARD TIME
 
The very mild temperatures of yesterday averaged 10 degrees warmer than
normal and pushed the monthly average up to 6.4 degrees above normal.
Warmer than normal temperatures continue with a morning low of 30F
running 8 degrees above normal.  Today's maximum of 42F is 4 degrees
warmer than average. 

Through the first 18 days accumulated departures are +119 in 2011 and
+115 degrees December, 2011, went on to become our second warmest
December on record at 37.5 degrees.  The warmest December is 38.1 degrees
in 2006.  

Today's observations:
 
7 A.M.
Weather: Clear, stratocumulus layer N-E-SSE, few stratocumulus
lenticularis ENE-E, few stratocumulus offshore distant SSW, few
altocumulus lenticularis disnt SSE-S   
Temperature: 31F; Dew Point: 28F; Wind: N at 9 kts,
Sea-level pressure: 30.15 ins. Hg, rising then more rapidly 
Visibility: 60 miles, distant haze all quadrants, virga distant
offshore NE-SE 
6-hour min. temp: 30F
BHO SA 1155 CLR 60 211/31/28/3509/015/ FEW SCSL ENE-E SC LYR XTDNG N-NE-SSE
VIRGA DSNT OFFSHR NE-SE FEW SC DSNT OFFSHR SSW FEW ACSL DSNT S-SSW DSNT HZ ALQDS/ 
8/540 53020 10036 20030 

10 A.M. 
Weather: Overcast stratocumulus with numerous breaks in the overcast, 
higher cirrus visible distant SW, virga distant offshore NE-SE  
Temperature: 35F; Dew Point: 29F; Wind: NW at 5 kts,
Sea-level pressure: 30.21 ins. Hg, rising then more slowly 
Visibility: 60 miles, virga distant offshore NE-SE, distant 
haze, visibility NW 70, montain in cloud 70 NW   
BHO SA 1455 E28 OVC 60 231/35/29/3105/021/ NMRS BINOVC ALQDS FEW CI
VSB DSNT SW BND MSTLY CLR SKY XTDNG SSW-WNW VIRGA OFFSHR DSNT NE-ESE
VSBY NW 70 MTN INCLD 70 NW LGT DSNT HZ/ 8/501 51020 

1 P.M.
Weather: Scattered cirrus and dense cirrus S-SW invading sky, 
stratocumulus all quadrants, few lower cumulus and moderate cumulus,
virga distant offshore NE-SE  
Temperature: 42F; Dew Point: 28F; Wind: ENE at 11 kts,
Wind: Wind direction gradually veering 
Sea-level pressure: 30.15 ins Hg, falling then more rapidly  
Visibility: 60 miles  
6-hour max. temp: 42F 
6-hour min. temp: 30F 
BHO SA 1755 220 SCT 60 211/42/28/0611/015/ SC ALQDS FEW LWR CU/MDT CU
ALQDS CI/DNS CI S-SW INVDNG VIRGA OFFSHR DSNT NE-SE DSNT HZ WND
GRDLY VEERING/ 8/802 58020 10042 20030

WEATHER SUMMARY FOR WEDNESDAY, DECEMBER 19

TEMPERATURE (DEGREES F)
MAX.....44      NORMAL.....38
MIN.....35      NORMAL.....23
MEAN....40      NORMAL.....30
 
DEPARTURE FROM 30-YEAR NORMAL....................+10
TOTAL DEPARTURE FOR THE MONTH...................+125 [+6.4 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............25    DEPARTURE........-10
TOTAL HEATING UNITS FOR THE MONTH...........476    DEPARTURE.......-127 
TOTAL HEATING UNITS FOR THE SEASON.........1626    DEPARTURE.......-238
TOTAL HEATING UNITS LAST SEASON TO DATE....1401    DIFFERENCE......+225

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...............42 WNW AT 10:06 A.M. 
                   AERO....................42 WNW AT 10:06 A.M.    
                   ASOS....................41 NW  AT 10:04 A.M.  
                   DAVIS...................42 WNW AT 10:06 A.M.  RMY: 43
THE FASTEST MILE FOR YESTERDAY.............28 NNW AT  3:49 P.M.   
MAXIMUM 2-MINUTE ASOS AVERAGE..............28 NNW AT  3:49 P.M. 
MAXIMUM 2-MINUTE DAVIS AVERAGE.............27 NW  AT  3:48 P.M.  
AVERAGE WIND SPEED AND DIRECTION.........18.3 NW 
                   ASOS..................17.6
                   DAVIS.................15.8 NW  [310 deg.]
* last of several occurrences....
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...trace   DEPARTURE..........-0.15
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.62   DEPARTURE..........-0.46
                         ASOS..............2.67
TOTAL PRECIPITATION FOR THE YEAR..........37.50   DEPARTURE.........-14.11
                         ASOS.............37.56

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........0.0    DEPARTURE..........-0.5
TOTAL SNOWFALL FOR THE MONTH...............0.9    DEPARTURE..........-6.3
TOTAL SNOWFALL FOR THE SEASON..............6.9    DEPARTURE..........-2.9	

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 40/31/36/+4/0.00/0.0/.../..     24 NNW AERO 22 MPH NNW RMY 21
12/16 36/31/34/+3/0.25/0.1/.../..     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/.../..       42 WNW AERO 40 MPN WNW RMY 43  

12/20 morning low temp: 30F; the normal low is now 22F

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 20
HIGH 61 IN 1957
LOW -16 IN 1942
PRECIP 1.69 INS. IN 1936
SNOWFALL 13.7 INS. IN 2009
PEAK GUST 75 MPH S IN 2002

RECORDS FOR DECEMBER 21
HIGH 60 IN 1957
LOW -10 IN 1942
PRECIP 2.01 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957

TODAY'S REPORT PREPARED BY: Robert Skilling/Patrick Peters