BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
  
DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, DECEMBER 10, 2007
ALL TIMES ARE IN EASTERN STANDARD TIME
 
LIGHT ICING EVENT COVERS SURFACES WITH 1/16 TO 1/8 GLAZE 
DECEMBER OFF TO COLDEST START SINCE 2003 AVERAGING 
NINE DEGREES COLDER THAN NORMAL THROUGH FIRST 9 DAYS
 
The light precipitation, which began late yesterday afternoon included a 
little sleet at the start, but fell mainly as light freezing rain and 
light freezing drizzle overnight.  Precipitation had ended as light
freezing drizzle by late this morning. The total melted precipitation
was 0.18 inch and had an average of 1/16 inch of thick glaze with up to
1/8 inch in some places. All of our anemometers kept turning with the exception
of the Aerovane propeller which stopped before midnight last evening.
 
Using the National Weather Service method of obtaining the monthly 
mean temperature shows this December to be our coldest through the first
nine days only since 2003. The month has been 9 degrees colder than the
30-year normal to date. Listed below are the coldest early Decembers 
(1st through 9th) in records checked back to 1960. This month has had 
the 6th coldest start during the past 47 years for December. 
 
Coldest Dec 1-9 (since 1960, NWS means)
 
1) 19.0 in 1989
2) 22.6 in 1976
3) 23.9 in 1964
4) 24.4 in 2002
5) 25.5 in 2003
6) 25.6 in 2007
7) 25.9 in 2000
 
Today's observations:
 
7 A.M.   
Weather: Obscurement, light freezing drizzle and heavy fog  
Temperature: 30F, Dew point: 30F, Wind: N at 5 kts
Sea-level pressure: 30.25 inches Hg, rising 
Visibility: 1/8 mile, light freezing drizzle, heavy fog
6-hour min temp: 29F 
24-hour precip: 0.16   
24-hour snowfall: trace  
Snow on ground: 1 inch  
BHO SA 1155 W3 X 1/8ZL-F 243/30/30/3605/025/ 
PCPN VRY LGT TOTAL GLZ ACCUM 1/16 IN/ 8//// 
4/001 55004 ASOS 60007 MANUAL 6015/ ASOS 70014 
MANUAL 70016 10030 20029
 
10 A.M.
Weather: Obscurement with fog, light freezing drizzle   
Temperature: 28F, Dew point: 28F, Wind: NNW at 8 kts
Sea-level pressure: 30.25 inches Hg, steady 
Visibility: 1/8 miles, variable to 1/4 mile 
3-hourly precip: 0.02 inch
Glaze: trace  
BHO SA 1455 W3 X 1/8VZL-F 244/28/28/3408/025/ 
STRA DRFTG OVR SMT VSBY 1/8V1/4 THN GLZ ACCUM WND 31V02/ 
8//// 53001 ASOS 60002 MANUAL 6002/
 
1 P.M.
Weather: Obscurement with fog    
Temperature: 30F, Dew point: 30F, Wind: N at 7 kts
Sea-level pressure: 30.22 inches Hg, falling 
Visibility: 1/8 mile 
6-hourly precip: 0.02 inch
Glaze: trace  
6-hourly min. temp: 28F
BHO SA 1755 W3 X 1/8F 234/30/30/3507/022/ THN GLZ ACCUM PST 6 HRS/ 
8//// 58010 ASOS 60002 MANUAL 6002/ 10030 20028
 
WEATHER SUMMARY FOR SUNDAY, DECEMBER 9
 
TEMPERATURE (DEGREES F)
MAX.....33    NORMAL.....40 
MIN.....25    NORMAL.....26
MEAN....29    NORMAL.....33
DEPARTURE FROM 30-YEAR NORMAL.......... -4 
TOTAL DEPARTURE FOR THE MONTH..........-79 [-9.0 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............36  DEPARTURE......+ 4
TOTAL HEATING UNITS FOR THE MONTH...........353  DEPARTURE......+80 
TOTAL HEATING UNITS FOR THE SEASON.........1433  DEPARTURE.....-129
TOTAL HEATING UNITS LAST SEASON TO DATE....1303  DIFFERENCE....+130
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............16  NW  AT  2:00 A.M.             
                   AEROVANE.............15  NW  AT 12:36 A.M.        
                   ASOS.................14  NW  AT 12:36 A.M.              
                   DAVIS................15  WNW AT 12:34 A.M.  .              
FASTEST MILE FOR YESTERDAY..............10  WNW AT  1:58 A.M.          
MAXIMUM 2-MINUTE ASOS AVERAGE...........12  WNW AT  1:58 A.M.          
MAXIMUM 2-MINUTE DAVIS AVERAGE..........12  S   AT  1:10 P.M.             
AVERAGE WIND SPEED AND DIRECTION........5.4 SW 
                   ASOS.................5.7        
                   DAVIS................5.1 WSW [240 deg]     
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.16  DEPARTURE....+0.01
                         ASOS..............0.14 
TOTAL PRECIPITATION FOR THE MONTH..........0.88  DEPARTURE....-0.47
                         ASOS..............0.87  
TOTAL PRECIPITATION FOR THE YEAR..........39.72  DEPARTURE....-8.29
                         ASOS.............39.09  
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........trace DEPARTURE.....-0.3
TOTAL SNOWFALL FOR THE MONTH................2.7  DEPARTURE.....+0.4 
TOTAL SNOWFALL FOR THE SEASON...............3.5  DEPARTURE.....-1.7
 
PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2007...CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
 
AERO: Aerovane recording wind system when significant
TSTM: Thunderstorm day
....: Data not yet available
 
12/1 33/15/24/-12/0/0/493/88       54 WNW 
12/2 24/15/20/-16/0.03/0.3/000/00  28 WNW 
12/3 38/23/31/-4/0.62/1.7/000/00   47 W 
12/4 27/17/22/-13/T/T/106/19       48 W       
12/5 29/17/23/-12/T/T/239/43       23 WNW
12/6 28/15/22/-12/0/0/554/100      31 WNW
12/7 34/21/28/-6/0.07/0.7/.../..   24 SSW
12/8 41/25/33/0/0.00/0.0/.../..    32 W
12/9 33/25/29/-4/N/A/T/.../..      16 NW 
 
12/10 morning low temp. 29F; normal low is now 25F 
  
NEW DAILY RECORDS FOR DECEMBER 2007: NONE
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR DECEMBER 10
HIGH 62 IN 1946
LOW -6 IN 1902
PRECIP 1.67 INCHES IN 1907
SNOWFALL 6.0 INCHES IN 1905
PEAK GUST 66e SW IN 1940
 
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
 
TODAY'S REPORT PREPARED By: Robert Skilling/Mike Iacono