BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, DECEMBER 20, 2009
ALL TIMES ARE IN EASTERN STANDARD TIME
 
TOTAL SNOWFALL 13.3 INCHES AT 1 P.M.
MODERATE SNOW CONTINUES THROUGH 2 P.M.
 
13.3 inches of snow were measured at 1 P.M
with 1.03 inches of melted precipitation for a
snow to liquid ratio of 13:1. Temperatures remained
steady in the upper teens through much of the
event while winds backed from the north to
the west-northwest early this morning.
 
Snow continues to drift here on the summit with
wind gusts to 35 MPH. Winds have relaxed slightly
since the daily peak gust of 42 MPH NNW at 4:17 A.M.
Snow drift maxima are over 17 inches while minima
are near 8 inches.
 
Today's observations:
 
1 P.M.
Weather: Sky obscured, moderate snow and fog
Temperature: 19F, Dew point: 17F, Wind: WNW at 18G22 kts,
Wind: Peak gust 29 kts from the west at 12:23 P.M.
Sea-level pressure: 29.53 inches Hg, falling  
Visibility: 1/4 mile
6-hour max. temp: 19F  
BHO SA 1755 W5 X 1/4SF 999/19/17/2918G22/953/ PK WND 2729/1723 SNW 
STRM  TOTAL 13.3 IN AND LIQUID EQUIV 1.03 IN/ 8//// 58005 MANUAL 6044/ 
ASOS 60059/ 10019 20017
 
WEATHER SUMMARY FOR SATURDAY, DECEMBER 19
 
TEMPERATURE (DEGREES F)
MAX.....30     NORMAL.....38
MIN.....14     NORMAL.....23
MEAN....22     NORMAL.....30
 
DEPARTURE FROM 30-YEAR AVERAGE.............-8
TOTAL DEPARTURE FOR THE MONTH..............-5  [-0.5 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............43    DEPARTURE........+8
TOTAL HEATING UNITS FOR THE MONTH...........616    DEPARTURE.......+10
TOTAL HEATING UNITS FOR THE SEASON.........1776    DEPARTURE......-119
TOTAL HEATING UNITS LAST SEASON TO DATE....1813    DIFFERENCE......-37
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............38 N   AT 10:19 P.M.
                   AEROVANE..............37 N   AT 11:15 P.M.
                   ASOS..................38 NNE AT 10:18 P.M.    
                   DAVIS.................42 N   AT N/A
THE FASTEST MILE FOR YESTERDAY...........27 N   AT 11:44 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE............25 NNE AT 11:45 P.M.   
MAXIMUM 2-MINUTE DAVIS AVERAGE...........26 N   AT N/A
AVERAGE WIND SPEED AND DIRECTION.......11.5 N
                   ASOS................11.3  
                   DAVIS...............11.3 NNW [343 DEG]
* Last of several occurrences
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.59   DEPARTURE....+0.45
                         ASOS..............0.50
TOTAL PRECIPITATION FOR THE MONTH..........4.53   DEPARTURE....+1.76
                         ASOS..............4.51
TOTAL PRECIPITATION FOR THE YEAR..........54.10   DEPARTURE....+4.67
                         ASOS.............55.27
                 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........N/A  DEPARTURE......N/A
TOTAL SNOWFALL FOR THE MONTH............... N/A  DEPARTURE......N/A
TOTAL SNOWFALL FOR THE SEASON...............N/A  DEPARTURE......N/A
                                               
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/-8/0/0/548/100      36 W    AERO 33 MPH W 
12/13 46/23/35/+3/0.74/0/274/50    35 SSE  AERO 31 MPH SSE
12/14 41/33/37/+6/0/0/186/34       29 NW
12/15 46/34/40/+9/0/0/006/01       35 W    AERO 32 MPH W
12/16 35/22/29/-2/T/T/459/84       43 W    AERO 44 MPH W
12/17 22/7/15/-16/0/0/545/100      52 WNW  AERO 52 MPH WNW
12/18 26/6/16/-14/0/0/.../..       37 W    AERO 37 MPH W
12/19 30/14/22/-8/0.01/0.1/..../.. 38 N
 
12/20 morning low temp: 16F; the normal low is now 22F 
 
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 20
HIGH 61 IN 1957
LOW -16 IN 1942
PRECIP 1.69 INS. IN 1936
SNOWFALL 8.3 INS. IN 1995
PEAK GUST 75 MPH S IN 2002
 
RECORDS FOR DECEMBER 21
HIGH 60 IN 1957
LOW -10 IN 1942
PRECIP 2.01 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957
 
TODAY'S REPORT PREPARED BY: Andy Hoell/Stephanie Radner