BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, DECEMBER 15, 2009
ALL TIMES ARE IN EASTERN STANDARD TIME
 
A CLOUDY AND MILD DAY  
TEMPERATURES REACH MID-40'S
 
Only a very few glimpses of the sun have
appeared today although there have been
many bright spots in the overcast.
Temperatures remained well above the
freezing point last night with the low
of 36F occurring just after midnight.
South-southeast winds veered to south
and southwest early today bringing in
the milder air and dew points rose from
the low to mid 30's to near 40 degrees.
A trace of snow remains in patches
both at the summit and on surrounding
terrain.
 
Today's observations:
 
7 A.M.
Weather: Low overcast stratus
Temperature: 41F, Dew point: 40F, Wind: SSW at 12 kts
Sea-level pressure: 29.89 inches Hg, rising
Visibility: 2 miles, thin fog
6-hour minimum temp: 36F
24-hour precipitation: 0.00 in.
Average snow depth: trace
BHO SA 1155 E3 OVC 2F 121/41/40/2012/989/
8/6// 55008 10041 20036
 
10 A.M.
Weather: Overcast altocumulus partly translucidus,
small brk in overcast overhead, numerous bright spots
in the overcast  
Temperature: 43F, Dew point: 41F, Wind: SW at 8 kts
Sea-level pressure: 29.88 inches Hg, falling  
Visibility: 12 miles, light fog  
BHO SA 1455 E70 OVC 12 117/43/41/2208/988/
FEW STRA ALQDS SML BINOVC OVHD NMRS BRGHT
SPTS IOVC THN FG ALQDS/ 8/67/ 56004
 
1 P.M.
Weather: Broken stratocumulus, overcast altocumulus,
partly translucidus, bright spots in overcast
Temperature: 45F, Dew point: 40F, Wind: SW at 7 kts
Sea-level pressure: 29.83 inches Hg, falling  
Visibility: 20 miles, 25 miles west thru north, hazy 
BHO SA 1755 E42 BKN 55 OVC 20 100/45/40/2307/983/
NMRS BRGHT SPTS IOVC VSBY W-N 25 HAZY ALQDS/
8/5// 58017 10046 20041
 
WEATHER SUMMARY FOR MONDAY, DECEMBER 14
 
TEMPERATURE (DEGREES F)
MAX.....41     NORMAL.....39
MIN.....33     NORMAL.....24
MEAN....37     NORMAL.....31
 
DEPARTURE FROM 30-YEAR AVERAGE.............+6
TOTAL DEPARTURE FOR THE MONTH.............+26  [+1.7 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............28    DEPARTURE........-5
TOTAL HEATING UNITS FOR THE MONTH...........413    DEPARTURE.......-23
TOTAL HEATING UNITS FOR THE SEASON.........1573    DEPARTURE......-152
TOTAL HEATING UNITS LAST SEASON TO DATE....1669    DIFFERENCE......-96
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............29 NW  AT  4:48 A.M. 
                   AEROVANE..............28 NW  AT  4:43 A.M.  
                   ASOS..................28 NW  AT  4:48 A.M.  
                   DAVIS.................30 WNW AT  4:37 A.M. 
THE FASTEST MILE FOR YESTERDAY...........22 WNW AT  4:42 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE............21 WNW AT  4:43 A.M. 
MAXIMUM 2-MINUTE DAVIS AVERAGE...........23 WNW AT  4:44 A.M. 
AVERAGE WIND SPEED AND DIRECTION.......11.3 WNW 
                   ASOS................10.7
                   DAVIS...............11.3 WNW [300 DEG]
 
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..........3.94   DEPARTURE....+1.87
                         ASOS..............4.01
TOTAL PRECIPITATION FOR THE YEAR..........53.51   DEPARTURE....+4.78
                         ASOS.............54.77
                 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.....-0.4
TOTAL SNOWFALL FOR THE MONTH...............11.0  DEPARTURE.....+7.1
TOTAL SNOWFALL FOR THE SEASON..............14.0  DEPARTURE.....+7.2
                                               
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/-5/0.09/0.6/513/93  36 NW
12/7  36/25/31/-3/0/0/050/09       22 WSW
12/8  39/25/32/-3/0/0/512/93       27 WNW
12/9  45/29/37/+4/1.23/5.7/000/00  52 ENE  AERO 46 MPH ENE
12/10 40/26/33/0/0/0/351/64        46 WSW  AERO 39 MPH W
12/11 26/20/23/-9/0/0/395/72       46 WSW  AERO 41 MPH WSW
12/12 30/18/24/-8/0/0/.../..       36 W    AERO 33 MPH W 
12/13 46/23/35/+3/0.74/0/.../..    35 SSE  AERO 31 MPH SSE
12/14 41/33/37/+6/0/0/.../..       29 NW
 
12/15 our morning low temp: 36F; the normal low is now 24F
 
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 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: Robert Skilling