BLUE HILL METEOROLOGICAL OBSERVATORY 
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, JANUARY 6, 2011
ALL TIMES ARE IN EASTERN STANDARD TIME
 
FIRST COLDER THAN NORMAL DAY IN OVER A WEEK
TEMPS. STRUGGLE UP TO ONLY AROUND 30F
"SUN DOG" AND HALO SEEN IN HIGH CLOUDS TODAY
 
After a morning low of 17F the thermometer is
struggling to reach 30F early this afternoon.
Our much warmer than normal January may soon
be a thing of the past as the average temperature is
reduced closer to normal after today becomes the
first below normal temperature day in over a week
or since December 28.
 
High clouds have been increasing today
and a bright parahelion (sun dog) was seen 
between 8 and 9 AM followed by a halo early
this afternoon. 
 
Today's observations: 
 
7 A.M.  
Weather: Scattered cirrocumulus, cirrocumulus lenticularis,
thin scattered cirrus radiatus, few cumulus, stratocumulus
layer along and offshore NE-ESE, few altocumulus and alto-
cumulus lenticularis all quadrants
Temperature: 18F, Dew point: 11F; Wind: WSW at 9 kts 
Sea-level pressure: 29.75 inches Hg, rising slightly
Visibility: 35 miles, except 45 miles west-northwest,
distant haze 
6-hourly min. temp. 18F 
Total snow depth on ground: 2 inches
BHO SA 1155 220 SCT 250 –SCT 35 067/18/11/2409/973/
FEW CY SC LYR ALG/OFFSHR NE-ESE FEW AC/ACSL LWR CI/CCSL 
ALQDS VSBY WNW 45 DSNT HZ/ 8/549 4/002 55002 10020 20018 
 
10 A.M.  
Weather: Thin scattered cirrus, line of small cumulus along
shore NE-ESE, patches cirrocumulus and cirrocumulus lenticularis,
lower cirrus all quadrants 
Temperature: 25F, Dew point: 14F; Wind: W at 5 kts
Sea-level pressure: 29.72 inches Hg, falling
Visibility: 55 miles, 65 miles NW, light distant haze  
BHO SA 1455 300 –SCT 55 063/25/14/2605/972/ LINE SML CU ALGSHR 
NE-ESE PTCHS CC/CCSL AND LWR CI ALQDS VSBY NW 65 THN K LYR ALG 
HRZN WSW-N-E LGT DSNT HZ/ 8/109 58004 
 
1 P.M.   
Weather: Overcast mostly dense cirrus and cirrostratus with
patches of high altocumulus, some lenticulars, few cumulus
SSW-WNW, halo,few thin spots in overcast and break distant NW-NE 
Temperature: 29F, Dew point: 12F; Wind: W at 2 kts (estimated), 
Wind: Light
Sea-level pressure: 29.65 inches Hg, falling 
Visibility: 60 miles, 75 NW, 35 NE-SE light haze,
thin smoke layer NW-E 
6-hourly max. temp: 29F
BHO SA 1755 200 SCT E220 OVC 60 040/29/12/E2602/965/ FEW CU SSW-WNW 
FEW AC/ACSL DNS CI ALQDS HALO FEW THN SPTS IOVC BINOVC DSNT NW-NE
THN K LYR NW-E VSBY NW 75 VSBY NE-SE 35 LGT HZ WND LGT/
8/147 58023 10029 20017 
 
WEATHER SUMMARY FOR WEDNESDAY, JANUARY 5
 
TEMPERATURE (DEGREES F)
MAX.....37     NORMAL.....34
MIN.....22     NORMAL.....19
MEAN....30     NORMAL.....27
 
DEPARTURE FROM 30-YEAR NORMAL.................+3
TOTAL DEPARTURE FOR THE MONTH................+39 [+7.6 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............35    DEPARTURE........-3
TOTAL HEATING UNITS FOR THE MONTH...........151    DEPARTURE.......-39
TOTAL HEATING UNITS FOR THE SEASON.........2403    DEPARTURE......-116
TOTAL HEATING UNITS LAST SEASON TO DATE....2449    DIFFERENCE......-46
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..............35 W     AT  2:22 P.M. 
                   AEROVANE...............38 W     AT  2:22 P.M.      
                   ASOS...................35 WSW   AT  3:28 P.M. 
                   DAVIS..................37 WSW   AT  2:18 P.M.  
THE FASTEST MILE FOR YESTERDAY........... 27 W     AT  2:19 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE.............26 W     AT  2:20 P.M. 
MAXIMUM 2-MINUTE DAVIS AVERAGE............28 W     AT  2:19 P.M.  
AVERAGE WIND SPEED AND DIRECTION........13.9 W
                   ASOS.................12.9               
                   DAVIS................12.9 W [260 DEG]
  
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......... 0.21  DEPARTURE........-0.54
                         ASOS..............0.21  
TOTAL PRECIPITATION FOR THE YEAR...........0.21  DEPARTURE........-0.54
                        ASOS.............  0.21
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.....-0.5
TOTAL SNOWFALL FOR THE MONTH................0.0  DEPARTURE.....-2.5
TOTAL SNOWFALL FOR THE SEASON..............23.0  DEPARTURE.....+6.9 
 
PRELIMINARY CLIMATE SUMMARY FOR JANUARY 2011 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
 
1/1 57/37/47/+20/0.00/0.0/.../..    25 S
1/2 47/33/40/+13/0.21/0.0/.../..    38 WNW  AERO 44 MPH WNW
1/3 33/23/28/+1/0.00/0.0/.../..     40 NW   AERO 48 MPH NW
1/4 37/21/29/+2/0.00/0.0/.../..     29 SSW  AERO 35 MPH SSW
1/5 37/22/30/+3/0.00/0.0/.../..     35 W    AERO 38 MPH W
 
1/6 our morning low temp: after 7 AM, 17F; the normal low is now 19F
 
DAILY RECORDS FOR JANUARY 2011
None so far.                             
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR JANUARY 6
HIGH 66F IN 2007
LOW -14F IN 1896
PRECIP 3.10 INS. IN 1889 [RECORD FOR MONTH]
SNOWFALL 7.5 INS. IN 1893
PEAK GUST 70 MPH WNW IN 1959
 
RECORDS FOR JANUARY 7
HIGH 60F IN 1930
LOW -7F IN 1896
PRECIP 1.97 INS. IN 1977
SNOWFALL 16.0 INS. IN 1977
PEAK GUST 74 MPH NW IN 1968
 
TODAY'S REPORT PREPARED BY: Robert Skilling