BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, SEPTEMBER 22, 2009 
ALL TIMES ARE IN EASTERN STANDARD TIME
 
AUTUMNAL EQUINOX OCCURS AT 5:18 P.M. EDT
THE FEEL OF SUMMER RETURNS AS FALL BEGINS
ONLY 8 DAYS ABOVE NORMAL DURING PAST 21 DAYS
MONTHLY RAINFALL FALLING FARTHER BELOW NORMAL
 
The beginning of fall will occur late this
afternoon as we return to warmer than normal
weather after a cool first three weeks of
the month. The warming trend began yesterday
which averaged 3 degrees on the plus side of
average for the date.  Considerable dense
high cloudiness is shutting out some of our
sunshine today during a month which has been
quite sunny with 68% of the possible bright
sunshine through 21 days.  
Measurable rain has been recorded on only 3
days this month, well below the normal frequency
for daily precipitation during September. However,
the total amount of 2.29 inches is now just a
little more than one half inch drier than
normal to date.  
 
Today's observations:
 
7 A.M.  
Weather: Obscurement with heavy fog 
Temperature: 59F, Dew point: 59F, Wind: SSW at 7 kts,
Sea-level pressure: 30.32 inches Hg, steady
Visibility: 1/16 mile  
6-hour minimum temp: 55F
24-hour precipitation: 0.00
BHO SA 1155 W1 X 1/16F 267/59/59/2107/032/
8//// 51004 10059 20055 
 
10 A.M.
Weather: Scattered stratocumulus, scattered altocumulus
at two levels and the state of sky is chaotic altocumulus,
with dense cirrus present all quadrants, thin spots in the
higher cirrus clouds and breaks in overcast 
Temperature: 68F, Dew point: 61F, Wind: SSW at 10 kts,
Wind: Direction variable S to WSW  
Sea-level pressure: 30.32 inches Hg, falling
Visibility: 35 miles, NE-SE 25 miles 
BHO SA 1455 20 SCT 180 SCT E200 BKN 220 BKN 250 OVC 35 266/68/61/2110/032/
PTCHS LWR AC/AC CHAOTIC SKY DENS CI ALQDS OVC PTLY THN BINOVC
VSBY NE-SE 25 LGT DSNT HZ WND 17V24/ 8/592 58001
 
1 P.M. 
Weather: High dense cirrus and cirrostratus overcast (two layers)
Temperature: 73F, Dew point: 59F, Wind: SW at 11 kts,
Wind: Direction variable S to WSW,
Wind: Gust to 21 kts past hour
Sea-level pressure: 30.27 inches Hg, falling
Visibility: 45 miles, light distant haze
6-hourly max. temp: 74F
BHO SA 1755 200 SCT E220 OVC 45 251/73/59/2311/027/
FEW SC ALQDS FEW THN SPTS IOVC OVHD BINOVC DSNT E-SE
LGT DSNT HZ WND 18V25 GST TO 21 KTS PST HR/
8/507 58015 10074 20059
 
WEATHER SUMMARY FOR MONDAY, SEPTEMBER 21
 
TEMPERATURE (DEGREES F)
MAX.....76    NORMAL.....69
MIN.....50    NORMAL.....51
MEAN....63    NORMAL.....60
 
DEPARTURE FROM 30-YEAR AVERAGE...........+3
TOTAL DEPARTURE FOR THE MONTH...........-31 [-1.7 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY.............2  DEPARTURE.......-4
TOTAL HEATING UNITS FOR THE MONTH............76  DEPARTURE.......+2
TOTAL HEATING UNITS FOR THE SEASON..........110  DEPARTURE.......+5
TOTAL HEATING UNITS LAST SEASON TO DATE......71  DIFFERENCE.....+39
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............20 S   AT  7:37 P.M.  
                   AEROVANE..............17 S   AT  7:37 P.M. 
                   ASOS..................18 S   AT  7:37 P.M.   
                   DAVIS................ 17 SSW AT  8:03 P.M.  
FASTEST MILE FOR YESTERDAY...............13 SSW AT 11:53 P.M.  
MAXIMUM 2-MINUTE ASOS AVERAGE............13 SSW AT 11:59 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE...........13 SSW AT 11:59 P.M.   
AVERAGE WIND SPEED AND DIRECTION....... 7.8 S
                   ASOS.................8.1
                   DAVIS................7.7 SW [220 DEG]
 
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..............2.29   DEPARTURE....-0.58
                         ASOS..............2.33
TOTAL PRECIPITATION FOR THE YEAR..........37.06   DEPARTURE....+0.72
                         ASOS.............38.25
 
PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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
 
9/1  71/51/61/-6/0/773/98     17 NW
9/2  76/54/65/-1/0/786/100    22 S
9/3  77/56/67/+1/0/587/75     19 SW
9/4  77/60/69/+3/0/764/98     18 NE
9/5  81/59/70/+5/0/591/76     25 NNW
9/6  64/53/59/-6/0/743/96     31 NNE
9/7  70/52/61/-4/0/709/92     20 WSW
9/8  75/56/66/+1/0/369/48     18 WSW  
9/9  68/55/62/-2/0/352/46     36 NNE  AERO 33 MPH NNE
9/10 65/53/59/-5/0/603/79     31 ENE
9/11 61/54/58/-6/0.49/000/00  30 NE
9/12 63/60/62/-1/1.74/000/00  30 NNE
9/13 76/58/67/+4/0.06/393/52  28 NW 
9/14 74/55/65/+2/0/699/93     22 WSW
9/15 75/56/66/+4/0/682/91     22 WNW
9/16 61/53/57/-5/T/060/08     31 NNE  AERO 29 MPH NNE
9/17 60/49/55/-7/0/022/03     27 N   
9/18 71/47/59/-2/T/571/77     35 WSW  AERO 30 MPH WSW
9/19 65/45/55/-6/0/716/97     30 NW   AERO 28 MPH WNW
9/20 71/45/58/-3/0/721/98     22 SW  
9/21 76/50/63/+3/0/703/96     20 S
 
9/22 our morning low temp. 55F; the normal low is 51F
 
NEW DAILY RECORDS FOR SEPTEMBER 2009 TO DATE...
None.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR SEPTEMBER 22
HIGH 90F IN 1895, 1914
LOW 30F IN 1904 (Earliest freeze)
PRECIP 1.16 INCHES IN 2001
PEAK GUST 60 MPH SSW IN 1989
 
RECORDS FOR SEPTEMBER 23
HIGH 93F IN 1895,1914
LOW 33F IN 1904
PRECIP 2.67 INCHES IN 1994
PEAK GUST 62 MPH SSW IN 1989
 
TODAY'S REPORT PREPARED BY: Robert Skilling