BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, JANUARY 20, 2009 
ALL TIMES ARE IN EASTERN STANDARD TIME
 
CLOUDS THIN OUT TO ALLOW SUNSHINE BY LATE MORNING
LIGHT NORTHWEST WINDS AND TEMPERATURES NEAR NORMAL
VISIBILITY ONLY 10 TO 12 MILES WITH HAZE 
 
Low clouds formed an overcast early this morning
but became scattered by late morning with bright
sunshine appearing through high thin cloudiness.
Light northwest winds prevailed and temperatures
were rising from a few degrees above the normal
low this morning to near 30 degrees by early
afternoon or just a few degrees colder than normal.
The airmass is moist today with dew points in 
the 20's and relative humidity only down to the
75% range by afternoon resulting in hazy conditions
and visibility limited to 10 to 12 miles.
 
7 A.M.
Weather: Broken stratocumulus, broken cirrus 
Temperature: 21F, Dew point: 17F, Wind: NW at 10 kts
Sea-level pressure: 29.62 inches Hg, rising
Visibility: 10 miles, thin fog
6-hour minimum temperature: 21F
Snow depth on ground: 16 inches
BHO SA 1155 E30 BKN 250 BKN 10 030/21/17/3210/962/
CI E-SE THN FG ALQDS/ 8/501 4/016 55000 10026 20021 
 
10 A.M.
Weather: Overcast stratocumulus, breaks in overcast  
Temperature: 24F, Dew point: 18F, Wind: WNW at 6 kts,
Sea-level pressure: 29.67 inches Hg, falling
Visibility: 10 miles, hazy
BHO SA 1455 E32 OVC 10 046/24/18/2906/967/
BINOVC HAZY/ 8/5// 53016
 
1 P.M.  
Weather: Scattered stratocumulus, scattered cirrus, and
thin broken cirrus   
Temperature: 28F, Dew point: 22F, Wind: NW at 10 kts
Sea-level pressure: 29.60 inches Hg, falling
Visibility: 12 miles, hazy 
6-hour maximum temperature: 29F
BHO SA 1755 38 SCT 220 SCT 250 –BKN 12 023/28/22/3110/960/
HAZY/ 8/501 56023 10029 20021
 
WEATHER SUMMARY FOR MONDAY, JANUARY 19
 
TEMPERATURE (DEGREES F)
MAX.....32    NORMAL.....33 
MIN.....19    NORMAL.....18
MEAN....26    NORMAL.....25
 
DEPARTURE FROM 30-YEAR NORMAL...............+1
TOTAL DEPARTURE FOR THE MONTH..............-84  [-4.6 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY.............39  DEPARTURE......... 0
TOTAL HEATING UNITS FOR THE MONTH............821  DEPARTURE........+86
TOTAL HEATING UNITS FOR THE SEASON..........3061  DEPARTURE.........-3
TOTAL HEATING UNITS LAST SEASON TO DATE.....2772  DIFFERENCE......+289
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............18  NW AT   2:51 A.M. *
                   AEROVANE.............16  NW AT   2:51 A.M. *  
                   ASOS.................18 NNW AT   2:46 A.M.         
                   DAVIS................20   N AT  12:44 A.M.          
FASTEST MILE FOR YESTERDAY..............14  NW AT   2:52 A.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE...........15 NNW AT   2:47 A.M.    
MAXIMUM 2-MINUTE DAVIS AVERAGE..........15  NW AT   2:46 A.M.             
                   AVERAGE.............8.1  S
                   ASOS................8.2
                   DAVIS...............7.7 WSW [250 deg]  
* last of several occurrences....
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.....0.00  DEPARTURE.........-0.16
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE MONTH...........2.86  DEPARTURE.........-0.10
                         ASOS...............3.94 #
TOTAL PRECIPITATION FOR THE YEAR............2.86  DEPARTURE.........-0.10
                         ASOS...............3.94 #
# Includes erroneous ASOS precipitation data on 1/1/09 and 1/2/09
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0   DEPARTURE.........-0.5
TOTAL SNOWFALL FOR THE MONTH...............20.6   DEPARTURE........+11.1
TOTAL SNOWFALL FOR THE SEASON..............51.0   DEPARTURE........+27.9
 
PRELIMINARY CLIMATE SUMMARY FOR JANUARY 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane recording wind system gust when significant
   TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
1/1  16/1/9/-18/0/0/538/98           44 WNW   Aero 44 MPH WNW
1/2  32/9/21/-6/0/0/005/01           28 S
1/3  32/21/27/0/T/T/539/98           43 WNW   Aero 44 MPH WNW
1/4  35/17/26/-1/0/0/512/93          36 W     Aero 33 MPH W
1/5  36/26/31/+4/0.06/0/512/93       30 W   
1/6  33/21/27/+1/0/0/183/33          27 W 
1/7  36/26/31/+5/1.26/0.8/000/00     46 NE    Aero 45 MPH NE
1/8  38/21/30/+4/0.01/0.1/389/70     47 W     Aero 45 MPH W
1/9  25/16/21/-5/0/0/546/98          37 W     Aero 36 MPH W
1/10 24/11/18/-8/0.10/1.0/329/59     28 W
1/11 31/19/25/-1/0.55/5.3/000/00     30 NW
1/12 27/18/23/-3/0.02/0.4/410/73     24 WNW
1/13 34/16/25/-1/0.04/T/107/19       25 SE
1/14 33/10/22/-4/0/0/518/92          47 W     Aero 48 MPH W
1/15 16/5/11/-15/0/0/000/00          20 NW
1/16 17/0/9/-17/0/0/557/98           26 W
1/17 19/1/10/-16/0/0/450/79          23 W
1/18 29/14/22/-4/0.58/9.5/000/00     24 E
1/19 32/19/26/+1/0.24/3.5/057/10     18 NW
 
1/20 morning low temp: 21F our normal low temp. is now 17F
    
NEW DAILY RECORDS FOR JANUARY 2009...
 
..NONE..
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR JANUARY 20
HIGH 59F IN 1951
LOW -9F IN 1901
PRECIP 1.95 INS. IN 1978
SNOWFALL 19.0 INS. IN 1978 [RECORD FOR MONTH]
PEAK GUST 76e MPH NE IN 1978
 
RECORDS FOR JANUARY 21
HIGH 65F IN 1906
LOW -4F IN 1888,1893
PRECIP 2.49 INS. IN 1979
SNOWFALL 7.5 INS. IN 2001
PEAK GUST 78e MPH SE IN 1979
 
TODAY'S REPORT PREPARED By: Robert Skilling