BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, DECEMBER 23, 2009
ALL TIMES ARE IN EASTERN STANDARD TIME
 
A COLDER DAY THAN YESTERDAY BUT SUNNY AGAIN
WEST WINDS CONTINUE AND ARE AGAIN GUSTY
 
Today's continued cold weather was again
accompanied by sunny conditions at least
into the early afternoon. High temperatures
had only reached 23F by 1 p.m. so this day
completes a week of much below normal cold. 
A very sunny day is one of seven or eight
this month, and December is very much on the
sunny side of the long-term average with
almost 60% of possible so far compared to the
normal of 46%.
 
Today's observations:
 
7 A.M.
Weather: Clear, stratocumulus along/offshore NE-SE and
along horizon distant SSE-S, few altocumulus and altocumulus
lenticularis northwest thru north-northeast
Temperature: 11F, Dew point: 3F, Wind: W at 11 kts,
Sea-level pressure: 30.06 inches Hg, rising
Visibility: 50 miles, 20 miles NE-SE, hazy
6-hour minimum temp: 10F
24-hour precipitation: 0.00 in.
24-hour snowfall: 0.0
Average snow depth: 11 ins.
BHO SA 1155 CLR 50 181/11/3/2711/006/ SC LYR ALG/OFFSHR NE-SE 
AND ALG HRZN DSNT SSE-S FEW AC/ACSL NW-NNE VSBY NE-SE 20 HAZY/
8/540 4/011 53002 10014 20010
 
10 A.M.
Weather: Clear, stratocumulus distant along/offshore NE-ESE and
along horizon distant SE-S, few altocumulus and altocumulus
lenticularis west thru north-northwest and patches of dense
cirrus west thru north-northwest 
Temperature: 18F, Dew point: 4F, Wind: W at 13G20 kts,
Wind: Direction variable WSW to WNW
Sea-level pressure: 30.09 inches Hg, falling slightly 
Visibility: 50 miles, light haze 
BHO SA 1455 CLR 50 188/18/4/2713G20/009/ SC ALG/OFFSHR NE-ESE 
AND DSNT ALG HRZN SE-S FEW AC/ACSL W-NNW DENS CI W-NNW LGT HZ
WND 24V30/ 8/542 51007
 
1 P.M.
Weather: Scattered cirrus, few cumulus, stratocumulus layer 
along/offshore to the northeast and east, few dense cirrus/
cirrocumulus   
Temperature: 22F, Dew point: 4F, Wind: W at 13G20 kts,
Wind: Direction variable WSW to WNW
Sea-level pressure: 30.01 inches Hg, falling  
Visibility: 60 miles  
6-hour max. temp: 23F
BHO SA 1755 220 SCT 60 164/22/4/2713G20/001/ FEW CU SC LYR ALG/
OFFSHR NE-E FEW SC ALQDS FEW DENS CI/CC WND 24V30/ 8/802
56024 10023 20010
 
WEATHER SUMMARY FOR TUESDAY, DECEMBER 22
 
TEMPERATURE (DEGREES F)
MAX.....28     NORMAL.....37
MIN.....14     NORMAL.....22
MEAN....21     NORMAL.....29
 
DEPARTURE FROM 30-YEAR AVERAGE.............-8
TOTAL DEPARTURE FOR THE MONTH.............-29  [-1.5 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............44    DEPARTURE........+9
TOTAL HEATING UNITS FOR THE MONTH...........746    DEPARTURE.......+35
TOTAL HEATING UNITS FOR THE SEASON.........1906    DEPARTURE.......-94
TOTAL HEATING UNITS LAST SEASON TO DATE....1950    DIFFERENCE......-44
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............35 W   AT 10:04 A.M. 
                   AEROVANE..............35 W   AT 10:04 A.M.  
                   ASOS..................33 W   AT 10:04 A.M.          
                   DAVIS.................36 W   AT 10:03 A.M.      
THE FASTEST MILE FOR YESTERDAY...........22 W   AT  6:33 P.M. * 
MAXIMUM 2-MINUTE ASOS AVERAGE............24 W   AT 12:22 P.M.     
MAXIMUM 2-MINUTE DAVIS AVERAGE...........26 W   AT  6:51 A.M.    
AVERAGE WIND SPEED AND DIRECTION...... 17.3 W
                   ASOS................15.7
                   DAVIS...............17.2 W [280 DEG]
* last of several occurrences....
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00   DEPARTURE....-0.15
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........4.99   DEPARTURE....+1.78
                         ASOS..............5.14
TOTAL PRECIPITATION FOR THE YEAR..........54.56   DEPARTURE....+4.69
                         ASOS.............55.90
                 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.....-0.4
TOTAL SNOWFALL FOR THE MONTH...............24.8  DEPARTURE....+17.7
TOTAL SNOWFALL FOR THE SEASON..............27.8  DEPARTURE....+18.2
                                               
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/-8/0/0/548/100      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/-14/0/0/540/99       37 W    AERO 37 MPH W
12/19 30/14/22/-8/0.01/0.1/000/00  38 N
12/20 26/16/21/-9/1.04/13.7/000/00 42 NNW
12/21 30/15/23/-7/0/0/409/75       45 WNW  AERO 45 MPH WNW
12/22 28/14/21/-8/0/0/.../..       35 W
 
12/23 our morning low temp: 10F; 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.
12/20 NEW RECORD DAILY SNOWFALL 13.7 INCHES;
      surpasses previous record of 8.3 inches in 1995
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR DECEMBER 23
HIGH 62 IN 1990
LOW -1 IN 1989
PRECIP 1.70 INS. IN 1947
SNOWFALL 11.9 INS. IN 1947
PEAK GUST 67 SSE IN 2004
 
RECORDS FOR DECEMBER 24
HIGH 58 IN 1996
LOW -6 IN 1943
PRECIP 2.21 INS. IN 1994
SNOWFALL 12.3 INS. IN 1961
PEAK GUST 79e MPH SE IN 1941
 
TODAY'S REPORT PREPARED BY: Robert Skilling