BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
  
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, SEPTEMBER 18, 2007    
ALL TIMES ARE IN EASTERN STANDARD TIME
 
LONG SPELL OF VERY QUIET, VERY SUNNY COOL AND 
DRY MID-SEPTEMBER WEATHER CONTINUES 
SEPTEMBER SUNSHINE WAY UP AT 70% OF POSSIBLE
 
This morning's low temperatures were just about a 
carbon copy of yesterday running up to 7 degrees 
cooler than normal.  The low reading here at Blue 
Hill was once again on 46 degrees.  Nearby, but at
a low elevation, Norwood Airport reported its first
freeze of the season with 30 degrees.  This was 
3 degrees colder than 24 hours ago.  The barometric
pressure showed very little change with the rather 
rare occurrence of exactly the same pressure at 
8 a.m. EDT this morning as was recorded both 12 and
24 hours earlier at 30.44 inches corrected to sea level.  
 
In addition to being a dry month, September is very 
sunny to date with 70% of the possible bright sunshine
recorded here through yesterday. Very cool temperatures
over the past several have lowered the monthly average
to slightly less than one degree warmer than normal. 
 
Today's observations:
 
7 A.M.   
Weather: Clear, few cumulus/stratocumulus along shore ENE-SE 
cirrus W-N and distant ESE-SE, steam fog over ponds SE 
dissipating past hour  
Temperature: 51F, Dew point: 40F, Wind: N at 10 kts 
Wind: direction gradually veering 
Sea-level pressure: 30.44 inches Hg, rising
Visibility: 40 miles, 55 W-NW    
6-hour min temp: 46F
24-hour rainfall: 0.00 in 
BHO SA 1155 CLR 40 308/51/40/0110/044/
FEW SC/CU ALGSHR NE-SE CI WSW-N AND DSNT ESE-SE 
INVSN DSSPTG PTCHS DENSE SHLW STEAM FG DSSPTNG OVR PONDS SE 
PST HR THN K LYR ALG HRZN S-SSW VSBY W-NW 55/ 
8/801 51006 10051 20046 
  
10 A.M.   
Weather: Scattered stratocumulus and cirrus clouds  
Temperature: 60F, Dew point: 47F, Wind: NNE @ 10G17 kts 
Wind: variability NNW-NE
Sea-level pressure: 30.46 inches Hg, rising
Visibility: 55 miles  
BHO SA 1455 22 SCT 250 SCT 55 315/60/47/0310G17/046/ 
WND 33V04 8/501 53007
 
1 P.M.   
Weather: Clear few cumulus, stratocumulus and cirrus   
Temperature: 63F, Dew point: 43F, Wind: NE @ 10 kts  
Wind: variability N-E
Sea-level pressure: 30.44 inches Hg, falling
Visibility: 55 miles  
6-hour max. temp: 63F  
6-hour precip: 0.00 in. 
BHO SA 1755 CLR 55 307/63/43/0510/044/ FEW CU W-NW 
SC DSNT E-SE FEW CI WND 01V09/ 8/801 56008 10063 20051 
 
WEATHER SUMMARY FOR MONDAY, SEPTEMBER 17
 
TEMPERATURE (DEGREES F)
MAX.....63    NORMAL.....71 
MIN.....46    NORMAL.....53
MEAN....55    NORMAL.....62
DEPARTURE FROM 30-YEAR NORMAL.........-7 
TOTAL DEPARTURE FOR THE MONTH........+17  [+0.8 DEGREES/DAY]
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..............20 NE AT 1:56 P.M. *
                   AEROVANE...............15 NE AT 1:56 P.M.  
                   ASOS...................N/A  #
                   DAVIS..................19 NE AT 2:04 P.M. 
FASTEST MILE FOR YESTERDAY................12 ENE AT 3:02 P.M.     
MAXIMUM 2-MINUTE ASOS AVERAGE.............N/A  # 
MAXIMUM 2-MINUTE DAVIS AVERAGE............15 ENE AT 1:57 P.M.  
AVERAGE WIND SPEED AND DIRECTION..........7.7  NE  
                   ASOS...................N/A  #
                   DAVIS..................7.8 NE [040 deg]
* last of several occurrences...
 
# ASOS WINDS SWITCHED OFF BY NWS 6/6, IT IS NOT KNOWN WHEN 
  THAT DATA WILL RESUME
 
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 THE MONTH..........1.86  DEPARTURE.....-0.45  
                         ASOS..............1.88    
TOTAL PRECIPITATION FOR THE YEAR..........32.85  DEPARTURE.....-2.93
                         ASOS.............32.11    
 
PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 2007...CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
 
AERO: Aerovane recording wind system when significant
TSTM: Thunderstorm day
....: Data not yet available
 
9/1  79/57/68/+1/0/790/100    25 WNW   
9/2  78/51/65/-1/0/787/100    22 S   
9/3  85/57/71/+5/0/760/97     31 SSW AERO 28 MPH SSW 
9/4  76/61/69/+3/0/641/82     28 NW  AERO 26 MPH NW
9/5  74/53/64/-1/0/732/94     21 ESE 
9/6  76/55/66/+1/0/380/49     31 S
9/7  92/62/77/+12/0/680/88    30 SSW
9/8  93/67/80/+15/0/686/89    31 S    TSTM 
9/9  72/57/65/+1/0.16/000/00  28 NNE  TSTM 
9/10 66/57/62/-2/0.03/000/00  18 NNE
9/11 68/58/63/-1/1.34/000/00  30 WNW  
9/12 73/55/64/+1/0/752/99     35 W    Aero 33 MPH W
9/13 73/52/63/0/0/741/98      23 ESE  
9/14 76/56/66/+3/0/587/78     26 SSE
9/15 63/49/56/-6/0.33/225/30  36 WNW  *
9/16 65/45/55/-7/0/606/81     20 WNW  
9/17 63/46/55/-7/0/.../99     20 NE  
 
9/18 morning low temp. 46F; the normal low is now 53F 
 
* precip. amount added for 15th
 
NEW DAILY RECORDS FOR SEPTEMBER 2007: 
 
9/7 - RECORD HIGH TEMPERATURE 92; PREVIOUS 91 IN 1945.
9/8 - RECORD HIGH TEMPERATURE 93; PREVIOUS 91 IN 1945.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR SEPTEMBER 18
HIGH 88F IN 1906
LOW 36F IN 1919
PRECIP 4.25 INCHES IN 1996
PEAK GUST 77e MPH WNW IN 1948
 
RECORDS FOR SEPTEMBER 19
HIGH 87F IN 1906,1983
LOW 37F IN 1929
PRECIP 3.69 INCHES IN 1936
PEAK GUST 48 MPH NE IN 1972
 
TODAY'S REPORT PREPARED By: Robert Skilling