BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
  
DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 11, 2009 
ALL TIMES ARE IN EASTERN STANDARD TIME 

Today's observations:

7 A.M. 
Weather: Clear, line of stratocumulus along horizon NE-SW
Temperature: 20F, Dew point: 5F, Wind: WSW at 15G31 kts,
Wind: Peak gust 35 kts WSW at 6:13 A.M.
Wind: Variable in direction S to WNW
Sea-level pressure: 29.86 inches Hg, rising
Visibility: 40 miles
6-hour minimum temp: 20F 
Total snow depth: 1 inch
BHO SA 1155 CLR 40 111/20/5/2415G31/986/ 
LN SC ALNG HRZN NE-SW PK WND 2535/13 WND 19V29/ 
8/500 4/001 53030 10025 20020

10 A.M. 
Weather: Clear, few cumulus
Temperature: 23F, Dew point: 3F, Wind: WSW at 22G33kts,
Wind: Peak gust 39 kts WSW at 9:43 A.M., 
Wind: Direction variable from SSW to WNW
Sea-level pressure: 29.91 inches Hg, rising   
Visibility: 45 miles  
BHO SA 1455 CLR 45 127/23/3/2522G33/991/ 
FEW SC PK WND 2439/43 WND 20V29/ 8/100 51016
  
1 P.M. 
Weather: Broken stratocumulus
Temperature: 24F, Dew point: 4F, Wind: WSW at 21G30kts,
Wind Peak wind 35 kts WSW at 11:56 P.M.
Sea-level pressure: 29.88 inches Hg, falling  
Visibility: 55 miles
6-hour maximum temp: 25F  
BHO SA 1755 E60 BKN 55 56009 118/24/4/2521G30/988/ 
PK WND 2435/1656/ 8/500 56009 10025 20020
  
WEATHER SUMMARY FOR THURSDAY, DECEMBER 10

TEMPERATURE (DEGREES F)
MAX.....40     NORMAL.....40
MIN.....26     NORMAL.....25
MEAN....33     NORMAL.....33
 
DEPARTURE FROM 30-YEAR AVERAGE..............0
TOTAL DEPARTURE FOR THE MONTH.............+34  [+3.2 DEGREES/DAY]

HEATING DEGREE DAYS 
TOTAL HEATING UNITS FOR YESTERDAY............32    DEPARTURE.........0
TOTAL HEATING UNITS FOR THE MONTH...........272    DEPARTURE.......-33
TOTAL HEATING UNITS FOR THE SEASON.........1432    DEPARTURE......-162
TOTAL HEATING UNITS LAST SEASON TO DATE....1543    DIFFERENCE.....-111

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY.............46 WSW AT 11:30 P.M.
                   AEROVANE..............39 W   AT 11:49 P.M.     
                   ASOS..................43 W   AT 11:49 P.M.       
                   DAVIS.................42 W   AT  4:41 P.M.
THE FASTEST MILE FOR YESTERDAY...........32 WSW AT 11:32 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE............30 W   AT 11:52 P.M.    
MAXIMUM 2-MINUTE DAVIS AVERAGE...........31 WSW AT 11:33 P.M.     
AVERAGE WIND SPEED AND DIRECTION.......19.3 WSW
                   ASOS................18.3
                   DAVIS...............17.6 WSW [241 DEG] 
* last of several occurrences
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00   DEPARTURE....-0.15
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........3.20   DEPARTURE....+1.70
                         ASOS..............3.25 
TOTAL PRECIPITATION FOR THE YEAR..........52.77   DEPARTURE....+4.61
                         ASOS.............54.01
			
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.....-0.3
TOTAL SNOWFALL FOR THE MONTH...............11.0  DEPARTURE.....+8.4 
TOTAL SNOWFALL FOR THE SEASON..............14.0  DEPARTURE.....+8.5
	 							
PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust when significant
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized

12/1  41/28/35/-1/0/0/497/89       29 NW  
12/2  51/33/42/+6/0.08/0/345/62    30 SSE
12/3  67/47/57/+22/1.01/0/428/77   69 SSE  AERO 73 MPH SSE
12/4  52/40/46/+11/0/0/488/88      26 W
12/5  42/30/36/+1/0.79/4.7/000/00  36 N
12/6  33/25/29/-5/0.09/0.6/.../..  36 NW
12/7  36/25/31/-3/0/0/.../..       22 WSW
12/8  39/25/32/-3/0/0/.../..       27 WNW 
12/9  45/29/37/+4/1.23/5.7/000/00  52 ENE  AERO 46 MPH ENE
12/10 40/26/33/0/0/0/.../..        46 WSW  AERO 39 MPH W

12/11 our morning low temp: 20F; the normal low is now 25F 

NEW DAILY RECORD FOR DECEMBER 2009
12/3 NEW RECORD HIGH MAXIMUM TEMPERATURE of 67F; 
     surpasses previous record of 61F in 1932, 1950.

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: Stephanie Radner