BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
  
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, DECEMBER 18, 2007
ALL TIMES ARE IN EASTERN STANDARD TIME
 
LOW TEMPERATURE OF 10 DEGREES IS OUR COLDEST TO DATE
NORWOOD AIRPORT GOES DOWN TO 5 BELOW ZERO
 
The low temperature of 10 degrees this morning broke a five-way
tie of 15 degrees which was the previous monthly minimum.  This
morning's low was 13 degrees colder than normal and the month
continues to be a cold one averaging more than 6 degrees below 
the average.  Strong radiational cooling over a deep snow cover
allowed for some below zero minima in the local area. The Norwood
Airport, in the Neponset Valley, 3 miles to our southwest, had its
first below zero reading of the month and season with -5F. Taunton
Airport recorded 2F. Many spots were in the single numbers above 
zero including Plymouth Airport at 7F.  
  
Today's observations:
 
7 A.M.   
Weather: Clear, stratocumulus layer offshore distant ENE-ESE  
Temperature: 11F, Dew point: 5F, Wind: W at 09 kts
Sea-level pressure: 30.27 inches Hg, rising   
Visibility: 45 miles
6-hour min temp: 10F 
24-hour precip: 0.00 ins. 
24-hour snowfall: 0.0 ins. 
Snow on ground: 11 inches 
BHO SA 1155 CLR 45 250/11/5/2609/027/ SC LYR OFFSHR DSNT NE-ESE/ 
8/500 4/011 51023 10015 20010
  
10 A.M.
Weather:  Clear, few cirrus S-W, light haze  
Temperature: 20F, Dew point: 7F, Wind: W at 05 kts
Sea-level pressure: 30.31 inches Hg, rising  
Visibility: 45 miles   
BHO SA 1455 CLR 45 265/20/7/2805/031/ FEW CI S-W 
THN K LYR ALG HRZN W-NW AND NE-E LGT HZ/ 8/001 51015 
  
1 P.M.
Weather: High thin scattered cirrus  
Temperature: 27F, Dew point: 12F, Wind: W at 10 kts
Sea-level pressure: 30.28 inches Hg, falling 
Visibility: 45 miles, light haze   
6-hourly max. temp: 27F
BHO SA 1755 300 –SCT 45 254/27/12/2710/028/ THN CI S-W 
LGT HZ/ 8/001 56011 10027 20011 
 
WEATHER SUMMARY FOR MONDAY, DECEMBER 17
 
TEMPERATURE (DEGREES F)
MAX.....32    NORMAL.....38 
MIN.....15    NORMAL.....23
MEAN....24    NORMAL.....31
DEPARTURE FROM 30-YEAR NORMAL...........-7 
TOTAL DEPARTURE FOR THE MONTH.........-106 [-6.4 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............41  DEPARTURE.......+7  
TOTAL HEATING UNITS FOR THE MONTH...........647  DEPARTURE.....+110 
TOTAL HEATING UNITS FOR THE SEASON.........1727  DEPARTURE..... -99
TOTAL HEATING UNITS LAST SEASON TO DATE....1478  DIFFERENCE....+249
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............62 W  AT 3:20 A.M.  
                   AEROVANE.............65 W  AT 3:20 A.M.  
                   ASOS.................62 W  AT 3:20 A.M.  
                   DAVIS................62 W  AT 3:20 A.M.  
FASTEST MILE FOR YESTERDAY............. 50 W  AT 3:21 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...........47 W  AT 3:21 A.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE..........49 W  AT 3:21 A.M. 
AVERAGE WIND SPEED AND DIRECTION......24.3 W  
                   ASOS...............22.9          
                   DAVIS..............24.2 W [265 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..........3.72  DEPARTURE....+1.23
                         ASOS..............3.83  
TOTAL PRECIPITATION FOR THE YEAR..........42.56  DEPARTURE....-6.59
                         ASOS.............42.05  
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.....-0.4
TOTAL SNOWFALL FOR THE MONTH...............20.6  DEPARTURE....+15.5
TOTAL SNOWFALL FOR THE SEASON..............21.4  DEPARTURE....+13.4
 
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/111/20       48 W       
12/5  29/17/23/-12/T/T/244/44       23 WNW
12/6  28/15/22/-12/0/0/554/100      31 WNW
12/7  34/21/28/-6/0.07/0.7/000/00   24 SSW
12/8  41/25/33/0/0/0/452/82         32 W
12/9  33/25/29/-4/0.08/T/000/00     16 NW  
12/10 30/26/28/-5/0.10/0/000/00     18 N 
12/11 36/22/29/-3/0.09/0/258/47     25 S
12/12 44/22/36/+4/T/0/88/16         39 W
12/13 29/20/25/-7/1.08/9.2/000/00   24 ENE
12/14 37/20/29/-2/0.02/0.2/038/07   28 WSW
12/15 28/15/22/-9/0/0/.../..        31 WNW  
12/16 43/23/33/+2/1.62/8.5/000/00   54 NE 
12/17 32/15/24/-7/0/0/.../..        62 W
 
12/18 morning low temp: 10F; normal low now 23F
      total snow and ice on the ground 11 inches 
 
NEW DAILY RECORDS FOR DECEMBER 2007: 
Dec 13: Record daily snowfall of 9.2 inches surpasses previous 
record of 9.0 inches in 1902.
Dec.16: Record daily snowfall of 8.5 inches surpasses previousE
record of 7.0 inches in 1896.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
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
 
RECORDS FOR DECEMBER 19
HIGH 59 IN 1899
LOW -1 IN 1919
PRECIP 2.06 INS. IN 1986
SNOWFALL 14.1 INS. IN 1945
PEAK GUST 68 NE IN 1986
 
TODAY'S REPORT PREPARED By: Robert Skilling