BLUE HILL METEOROLOGICAL OBSERVATORY 
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 17, 2010
ALL TIMES ARE IN EASTERN STANDARD TIME
 
TEMPERATURES CONTINUE BELOW AVERAGE
UNDER CLEAR SKIES WITH LIGHT WINDS
 
Temperatures today are a couple of degrees warmer than yesterday,
but still running below average.  The average temperature for the
month of December is now running nearly 3 degrees below average.
December 2010 could end up being our first below average month
since last December.
 
The sky has been clear today with the exception of a few distant
cumulus clouds.  Visibility this afternoon is 60 miles, with some
light haze.  Winds have been relatively calm, ranging from 10-15 mph
with occasional gusts near 20 mph.
 
Today's observations: 
 
7 A.M.
Weather: Clear, line of cumulus/stratocumulus distant NNE-E-SE, few
moderate tops distant NE, few thin cirrus distant NE-E-SSE, thin
smoke layer along horizon SSW, inversion present
Temperature: 17F, Dew point: 13F; Wind: WNW at 10 kts,
Sea-level pressure: 29.79  inches Hg, rising
Visibility: 55 miles
6-hour minimum temp: 17F
Total snow depth: trace 
BHO SA 1155 CLR 55 089/17/13/2910/979/ LINE CU/SC DSNT NNE-E-SE FEW
MDT TOPS DSNT NE FEW THN CI DSNT NE-E-SSE THN K LYR ALG HRZN SSW
INVSN PRSNT/ 8/801 53010 10023 20017
 
10 A.M.
Weather: Clear, few cumulus/stratocumulus distant NE-E, few moderate
tops ENE, smoke layer SSW-N-E, distant haze
Temperature: 25F, Dew point: 16F; Wind: W at 6 kts,
Sea-level pressure: 29.85 inches Hg, rising
Visibility: 45 miles, smoke layer distant SSW-N-E, distant haze
BHO SA 1455 CLR 45 107/25/16/2805/985/ FEW CU/SC DSNT NE-E FEW MDT
TOPS ENE K LYR DSNT SSW-N-E DSNT HZ/ 8/200 51018
 
1 P.M.
Weather: Clear, few cumulus distant W-N, distant haze
Temperature: 33F, Dew point: 17F; Wind: W at 13 kts,
Wind: Direction variable SW to NW 
Sea-level pressure: 29.83 inches Hg, falling
Visibility: 60 miles, distant haze
6-hourly max. temp: 34F  
BHO SA 1755 CLR 60 103/33/17/2713/983/ FEW CU DSNT W-N DSNT HZ
WND 22V32/ 8/100 58004 10034 20017
 
WEATHER SUMMARY FOR THURSDAY, DECEMBER 16
 
TEMPERATURE (DEGREES F)
MAX.....32     NORMAL.....38
MIN.....15     NORMAL.....24
MEAN....24     NORMAL.....31
 
DEPARTURE FROM 30-YEAR NORMAL.................-7
TOTAL DEPARTURE FOR THE MONTH................-43 [-2.9 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............41    DEPARTURE........+7
TOTAL HEATING UNITS FOR THE MONTH...........550    DEPARTURE.......+47
TOTAL HEATING UNITS FOR THE SEASON.........1710    DEPARTURE.......-82
TOTAL HEATING UNITS LAST SEASON TO DATE....1634    DIFFERENCE......+76
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..............25 SSW  AT 11:14 A.M. 
                   AEROVANE...............29 SSW  AT 11:13 A.M. *
                   ASOS...................25 SSW  AT 11:14 A.M.    
                   DAVIS..................27 SSW  AT 10:50 A.M.    
THE FASTEST MILE FOR YESTERDAY............19 SW   AT  1:22 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE.............20 SSW  AT 12:14 P.M.     
MAXIMUM 2-MINUTE DAVIS AVERAGE............20 S    AT 12:14 P.M.      
AVERAGE WIND SPEED AND DIRECTION..........10.5 SW
                   ASOS...................10.3       
                   DAVIS..................9.3 SSW [212 DEG]
*last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M... 0.00  DEPARTURE........-0.14
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.43  DEPARTURE........+0.08
                         ASOS..............2.54 
TOTAL PRECIPITATION FOR THE YEAR..........60.46  DEPARTURE.......+11.45
                         ASOS.............60.45**
** ASOS missing rainfall due to system failure on 6/24-25
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M......... 0.0  DEPARTURE.....-0.4
TOTAL SNOWFALL FOR THE MONTH..............  0.2  DEPARTURE.....-4.5
TOTAL SNOWFALL FOR THE SEASON...............0.3  DEPARTURE.....-7.3 
 
PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2010 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  55/43/49/+13/0.49/0.0/000/00  55 SE   AERO 61 MPH SE
12/2  48/29/39/+3/0.00/0.0/540/100  30 W
12/3  38/29/34/-1/0.00/0.0/050/09   25 WNW
12/4  40/28/34/-1/0.00/0.0/516/93   27 WNW
12/5  34/23/29/-6/0.00/0.0/127/23   24 W
12/6  32/22/27/-7/0.00/0.0/447/81   37 WSW  AERO 38 MPH WSW
12/7  33/23/28/-6/0.00/0.0/463/84   35 W    AERO 37 MPH W
12/8  31/19/25/-8/0.00/0.0/.../..   39 W    AERO 40 MPH W
12/9  26/14/20/-13/0.00/0.0/.../..  29 WNW
12/10 25/9/17/-16/0.00/0.0/.../..   17 SSE
12/11 44/25/35/+3/0.00/0.0/.../..   23 WSW
12/12 55/33/44/+12/1.57/0.0/000/00  55 SE   AERO 69 MPH SE
12/13 55/33/44/+12/0.35/0.0/.../..  50 SSE  AERO 58 MPH SSE
12/14 33/16/25/-6/T/T/.../..        30 W
12/15 19/13/16/-15/0.02/0.2/.../..  33 WNW  AERO 38 MPH WNW 
12/16 32/15/24/-7/0.00/0.0/.../..   25 SSW
 
12/17 our morning low temp: 17F; the normal low is now 23F
 
NEW DAILY RECORDS FOR DECEMBER 2010
 
12/15 - NEW RECORD LOW MAXIMUM TEMP. OF 19F;
this surpasses the previous record of 20F 
in 1903,1905,1931, and 1962 
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR DECEMBER 17
HIGH 63 IN 2000
LOW -10 IN 1942
PRECIP 3.03 INS. IN 1888
SNOWFALL 7.5 INS. IN 1988
PEAK GUST 78 MPH SSE IN 2000
 
RECORDS FOR DECEMBER 18
HIGH 59 IN 1928
LOW -11 IN 1919
PRECIP 1.44 INS. IN 1915
SNOWFALL 7.0 INS. IN 1904
PEAK GUST 76e W IN 1978
 
TODAY'S REPORT PREPARED BY: Sean Fankhauser