BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, OCTOBER 20, 2009  
ALL TIMES ARE IN EASTERN STANDARD TIME
 
WARMING TREND BEGINS AFTER OVER A WEEK
OF UNUSUALLY COLD WEATHER
 
Temperatures have risen into the 60's for the first
time since 11 October. The warming trend begins
after over a week of unusually cold mid-October
weather. The past week has brought two record low daily 
maximum temperatures and two days of snowfall including
3 inches that equals the third greatest amount for any
day in October. 
 
Today's observations:
 
7 A.M.
Weather: Scattered dense cirrus, thin broken cirrus, patches of
altocumulus/altocumulus chaotic sky, few altocumulus lenticularis,
dense cirrus all quadrants, few cirrocumulus and cirrocumulus
lenticularis and few patches of snow virga
Temperature: 42F, Dew point: 27F, Wind: SW at 10 kts
Sea-level pressure: 30.13 inches Hg, rising
Visibility: 45 miles, NE 30, W-NW 55
6-hour minimum temp: 38F
BHO SA 1155 200 SCT 220 SCT 250 –BKN 300 -BKN 45 202/42/27/2210/013/
PTCHS ACSL/AC CHAOTIC DENS CI PTCHS SNW VIRGA FEW PTCHS CC/CCSL
FEW PTCHS THN FG BLO INVSN SE-SW-NW VSBY NE 30 W-NW 55/ 8/092 53004
100// 20038
 
10 A.M.
Weather: Broken altocumulus translucidus
Temperature: 54F, Dew point: 34F, Wind: SW at 8 kts,
Wind: Direction variable S to WSW 
Sea-level pressure: 30.11 inches Hg, falling
Visibility: 45 miles, thin smoke layer along horizon northwest
through northeast 
BHO SA 1455 E80 BKN 45 195/54/34/2208/011/ THN K LYR ALG HRZN NW-NE
WND 19V25/ 8/030 58007   
 
1 P.M.   
Weather: Clear, few altocumulus lenticularis all quadrants 
Temperature: 62F, Dew point: 37F, Wind: SW at 10 kts,
Wind: Direction variable south thru west 
Sea-level pressure: 30.06 inches Hg, falling
Visibility: 45 miles, distant haze 
6-hour maximum temp: 63F
BHO SA 1755 CLR 45 178/62/37/2310/006/ FEW ACSL ALQDS
DSNT HZ WND 18V27/ 8/040 58016 10063 20042 
 
WEATHER SUMMARY FOR MONDAY, OCTOBER 19
 
TEMPERATURE (DEGREES F)
MAX.....52     NORMAL.....59
MIN.....33     NORMAL.....42
MEAN....43     NORMAL.....51
 
DEPARTURE FROM 30-YEAR AVERAGE...........-8
TOTAL DEPARTURE FOR THE MONTH...........-91 [-5.0 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............22  DEPARTURE.......+7
TOTAL HEATING UNITS FOR THE MONTH...........308  DEPARTURE......+86
TOTAL HEATING UNITS FOR THE SEASON..........465  DEPARTURE......+74
TOTAL HEATING UNITS LAST SEASON TO DATE.....316  DIFFERENCE....+149
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............25 NNW AT   9:52 A.M. * 
                   AEROVANE..............25 NW  AT   2:29 A.M. *  
                   ASOS..................24 NW  AT   2:43 A.M.   
                   DAVIS.................27 NW  AT   2:-- A.M. 
FASTEST MILE FOR YESTERDAY...............16 NW  AT   5:04 A.M.  
MAXIMUM 2-MINUTE ASOS AVERAGE............17 NNW AT  12:04 A.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE...........18 NW  AT   5:-- A.M. 
AVERAGE WIND SPEED AND DIRECTION....... 9.0 NW 
                   ASOS.................8.8
                   DAVIS................9.5 WNW [300 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 MONTH..............4.53   DEPARTURE....+1.87
                         ASOS..............4.50
TOTAL PRECIPITATION FOR THE YEAR..........42.41   DEPARTURE....+2.15
                         ASOS.............43.56
 
PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/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
 
10/1  56/39/48/-9/0/155/22     27 WSW 
10/2  60/40/50/-6/0/442/63     23 SSE 
10/3  63/51/57/+1/1.10/000/00  32 ESE  AERO 30 MPH ESE 
10/4  67/57/62/+6/0/202/29     21 WSW
10/5  64/49/57/+2/0/595/86     33 W    AERO 31 MPH W
10/6  65/45/55/0/0/628/91      25 W
10/7  67/51/59/+4/0.70/344/50  54 W    AERO 54 MPH W
10/8  61/48/55/+1/0/602/88     43 W    AERO 39 MPH W
10/9  60/48/54/0/0.05/000/00   29 SSE
10/10 62/42/52/-2/0.26/205/30  37 NW
10/11 61/39/50/-3/0/655/97     35 WSW  AERO 33 MPH W 
10/12 53/36/45/-8/T/471/70     23 SSW
10/13 51/36/44/-8/0.20/074/11  35 WNW 
10/14 52/32/42/-10/0/494/74    27 NW
10/15 41/32/37/-15/0.19/000/00 29 NNE
10/16 41/33/37/-14/0.24/000/00 37 NNE  AERO 35 MPH NNE T SNOW
10/17 48/33/41/-10/0/250/38    35 NNE
10/18 46/32/39/-12/1.79/000/00 43 NNE  SNOWFALL 3.0 INS
10/19 52/33/43/-8/0/.../..     25 NNW
 
10/20 morning low temp: 38F; our normal low is now 42F
 
NEW DAILY RECORDS FOR OCTOBER 2009
10/7: NEW RECORD WIND GUST 54 MPH W AT 2005E;
      surpasses previous record of 52 MPH ESE in 1972
10/15: NEW RECORD LOW MAXIMUM TEMPERATURE 41;
      surpasses previous 47 set in 1887 and 1896
10/16: NEW RECORD LOW MAXIMUM TEMPERATURE 41;
      surpasses previous 42 set in 1940
10/18: NEW RECORD DAILY SNOWFALL 3.0 INS; 
      surpasses previous trace in 1972
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR OCTOBER 20
HIGH 78 IN 1965,1984
LOW 24 IN 1972
PRECIP 7.10 INCHES IN 1996 (RECORD FOR MONTH)
SNOWFALL TRACE IN 1934,1943
PEAK GUST 63 MPH W IN 1966
 
RECORDS FOR OCTOBER 21
HIGH 79 IN 1979
LOW 24 IN 1974
PRECIP 2.39 INCHES IN 1944
SNOWFALL TRACE IN 1895,1907,1940
PEAK GUST 69e MPH S IN 1976
 
TODAY'S REPORT PREPARED BY: Robert Skilling