BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
  
DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, DECEMBER 15, 2007
ALL TIMES ARE IN EASTERN STANDARD TIME

ARCTIC AIR MOVES IN TODAY AHEAD OF SNOW AND RAIN STORM
ON SUNDAY...
The temperature at midnight was 28 degrees, which will
likely be the high for the day.  An arctic cold front
moved through the area this morning, and the temperature
dropped to 15 degrees by 8 AM with a dew point of -1. 
The snow cover on the summit dropped nearly an inch from 
9.4 inches on Friday to 8.5 inches this morning, but 
rounded it remains at 9 inches.  The sea-level pressure
has topped out at 30.51 inches this morning, and it
will drop steeply tomorrow to about 29 inches by Sunday
evening as a strong storm crosses New England bringing 
more snow, sleet and rain.  

Today's observations:

7 A.M.   
Weather: Scattered altocumulus, scattered cirrus, thin
broken cirrus
Temperature: 17F, Dew point: -1F, Wind: WNW at 16G24 kts
Sea-level pressure: 30.41 inches Hg, rising
Visibility: 50 miles
6-hour min temp: 17F 
Snow on ground: 9 inches 
BHO SA 1155 150 SCT 200 SCT 250 –BKN 50 298/17/-1/3016G24/
041/ FEW SC DSNT NE-ESE PK WND 3026/23/ 8/571 4/009 51037 
10027 20017

10 A.M.
Weather: Scattered altocumulus, scattered cirrus, thin
overcast cirrus
Temperature: 17F, Dew point: 1F, Wind: NNW at 9 kts
Sea-level pressure: 30.51 inches Hg, rising rapidly past 30 
minutes
Visibility: 70 miles
BHO SA 1455 180 SCT 200 SCT 250 –OVC 70 332/17/1/3409/051/ 
FEW SC DSNT NE-SE PRESRR/ 8/571 51034

1 P.M.
Weather: Scattered altocumulus, thin overcast cirrus
Temperature: 21F, Dew point: 1F, Wind: NNW at 9 kts
Sea-level pressure: 30.48 inches Hg, falling
Visibility: 70 miles   
6-hourly max. temp: 22F
BHO SA 1755 150 SCT 250 –OVC 70 322/21/1/3409/048/ FEW LWR CI 
FEW SC DSNT NE-SE/ 8/571 58010 10022 20015

WEATHER SUMMARY FOR FRIDAY, DECEMBER 14

TEMPERATURE (DEGREES F)
MAX.....37    NORMAL.....39 
MIN.....20    NORMAL.....24
MEAN....29    NORMAL.....31
DEPARTURE FROM 30-YEAR NORMAL...........-2 
TOTAL DEPARTURE FOR THE MONTH..........-92 [-6.8 DEGREES/DAY] 

HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............36  DEPARTURE.......+3  
TOTAL HEATING UNITS FOR THE MONTH...........531  DEPARTURE......+95 
TOTAL HEATING UNITS FOR THE SEASON.........1611  DEPARTURE.....-114
TOTAL HEATING UNITS LAST SEASON TO DATE....1416  DIFFERENCE....+195

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............28 WSW AT 10:02 P.M.*
                   AEROVANE.............28 WSW AT  9:53 P.M.
                   ASOS.................26 W   AT  9:54 P.M.
                   DAVIS................29 WSW AT  9:53 P.M.
FASTEST MILE FOR YESTERDAY..............21 WSW AT  9:53 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE...........21 W   AT  9:55 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..........21 WSW AT  9:55 P.M.
AVERAGE WIND SPEED AND DIRECTION.......12.3 SW  
                   ASOS................11.7         
                   DAVIS...............11.8 WSW [244 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..........2.10  DEPARTURE....+0.03
                         ASOS..............2.28  
TOTAL PRECIPITATION FOR THE YEAR..........40.94  DEPARTURE....-7.79
                         ASOS.............40.50   

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.....-0.4
TOTAL SNOWFALL FOR THE MONTH...............12.1  DEPARTURE.....+8.2
TOTAL SNOWFALL FOR THE SEASON..............12.9  DEPARTURE.....+6.1

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/-2/0.02/0.2/38/7     28 WSW

12/15 morning low temp. 15F; normal low is now 24F

NEW DAILY RECORDS FOR DECEMBER 2007: 
Dec 13: Record daily snowfall of 9.2 inches surpasses previous 
record of 9.0 inches in 1902.

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 7.0 INS. IN 1896
WIND 73 MPH SSE IN 1982

TODAY'S REPORT PREPARED By: Mike Iacono

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