BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, JULY 29, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME
 
1/2 INCH OF RAINFALL IN 15-MINUTE DOWNPOUR 
WITH THE LIKELY BRIEF OCCURRENCE OF HAIL...  
TOTAL OF 0.90 INCH RAINFALL FOR THE DAY SATURDAY
 
A late afternoon thunderstorm dropped 0.23 inch in five 
minutes, 0.41 inch in 10 minutes, and 0.50 inch in just
15 minutes ending 5:30 P.M. EDT late Saturday afternoon.
The total rainfall for the day was 0.90 inch and the most
since 1.52 inches on June 4th.  The maximum amount this 
month had been 0.41 inch on July 8th.  The nearly one inch
of rain put a significant dent in what had become a rather 
large negative departure for July.  However, the month is 
still one inch drier than average.
 
After a high temperature reading of 87 degrees in the early 
afternoon along with very humid conditions (dewpoints near 70), 
the day's low temperature of 69 degrees was recorded as the 
thunderstorm and heavy rain was ending at 5:30 P.M. EDT.
 
I am rather certain than hail fell (stone size unknown) just as the 
late afternoon downpour was ending at 5:30 p.m. The evidence is 
seen in an unusual but telltale marking on our weighing gage 
rainfall trace.  In addition, a sudden drop in temperature was 
noted around the time and a minimum temperature of 69.1 occurred
at 5:26 p.m. 
 
Today's observations:
 
7 A.M.   
Weather: Partial obscurement with 7/10 of sky obscured by fog  
Temperature: 70F, Dew point: 70F, Wind: W at 06 kts
Wind: gradually veering past hour 
Sea-level pressure: 29.91 inches Hg, rising
Visibility: 1/2 mile, 2 east, 1 southeast in fog, slowly increasing  
6-hour min temp: 69F     
24-hour rainfall: 0.90 in. 
BHO SA 1155 –X 1/2F 140/70/70/2706/994/ F7 VSBY E 2 SE 1
VSBY INCRSG SLWLY WND GRDLY VEERING/ 51009 ASOS 70054 MANUAL 70053 10070 20069  
 
10 A.M.   
Weather: Scattered cumulus, moderate cumulus forming, few cirrus 
Temperature: 79F, Dew point: 69F, Wind: NNW at 048 kts
Wind: Light/variable
Sea-level pressure: 29.96 inches Hg, rising
Visibility: 15 miles, hazy  
BHO SA 1455 18 SCT 250 SCT 15 146/79/69/3404/996/ 
CU/MDT CU FRMG HAZY WND LGT/ 8/201 51006  
 
WEATHER SUMMARY FOR SATURDAY, JULY 28
 
TEMPERATURE (DEGREES F)
MAX.....87    NORMAL.....82 
MIN.....69    NORMAL.....63
MEAN....78    NORMAL.....72
DEPARTURE FROM 30-YEAR NORMAL........+6
TOTAL DEPARTURE FOR THE MONTH........+5  (0.0 DEGREES/DAY)
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..............24 WNW AT 4:15 P.M. *       
                   AEROVANE...............23   S AT 2:32 P.M.        
                   ASOS...................N/A  #
                   DAVIS..................28  S  AT 2:32 P.M.           
FASTEST MILE FOR YESTERDAY................16  S  AT 2:31 P.M. *           
MAXIMUM 2-MINUTE ASOS AVERAGE.............N/A  # 
MAXIMUM 2-MINUTE DAVIS AVERAGE............18  S  AT 2:32 P.M.             
AVERAGE WIND SPEED AND DIRECTION......... 8.5 S  
                   ASOS...................N/A  #
                   DAVIS................. 7.7 S [170 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....0.53  DEPARTURE.....+0.41
                         ASOS..............0.54 
TOTAL PRECIPITATION FOR THE MONTH..........2.37  DEPARTURE.....-1.01 
                         ASOS..............2.27    
TOTAL PRECIPITATION FOR THE YEAR..........29.35  DEPARTURE.....+0.30
                   ASOS FOR YEAR..........28.68    
 
PRELIMINARY CLIMATE SUMMARY FOR JULY 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
 
7/1  70/52/61/-9/0.02/649/71/ 28 W      
7/2  73/50/62/-8/0/841/92/    29 WNW 
7/3  75/53/64/-6/0/839/92/    23 NW 
7/4  78/58/68/-2/0.09/465/51/ 45 SSE 
7/5  80/61/71/ 0/0.25/383/42/ 38 SSE TSTM   
7/6  83/62/73/+2/0.01/482/53/ 46 WNW TSTM  
7/7  81/60/71/0/0/509/56/     32 WSW   
7/8  90/62/76/+5/0.41/563/62/ 36 NW Aero 33 MPH TSTM 
7/9  86/61/74/+3/0.20/354/39  27 NNE TSTM
7/10 80/62/71/0/0/680/75      27 S 
7/11 84/70/77/+5/T/371/41     32 S
7/12 81/64/73/+1/0.01/813/90  27 WNW
7/13 84/62/73/+1/0/695/77     36 WSW
7/14 82/62/72/0/T/765/85      33 SSE
7/15 87/65/76/+4/T/638/71     44 S  Aero 45 MPH S, Davis 48 MPH S     
7/16 84/65/75/+3/0/449/50     18 WNW 
7/17 85/65/75/+3/0/591/66     18 WNW
7/18 71/66/69/-3/0.21/000/00  23 SE   
7/19 83/65/74/+2/0.20/205/23  31 S   
7/20 82/61/72/0/0/330/37      29 WSW
7/21 77/58/68/-4/0/436/49     23 WNW 
7/22 77/61/69/-3/0/826/93     24 ENE   
7/23 64/60/62/-10/0.07/000/00 32 NNE
7/24 82/62/72/-1/0/796/90     25 SW
7/25 88/63/76/+3/0/.../..     21 WSW  Aero 18 MPH SW
7/26 91/65/78/+6/0/.../..     21 S
7/27 90/69/80/+8/0/.../..     29 S
7/28 87/69/78/+6/0.90/.../..  24 WNW  TSTM 
 
7/29 morning low temp. 69 deg; normal low now 63 deg.
  
NEW DAILY RECORDS FOR JULY 2007: 
 
None to date
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR JULY 29
HIGH 97F IN 1949
LOW  53F IN 1888,1914
PRECIP 1.53 INCHES IN 1901
PEAK GUST 40e MPH E IN 1941
 
RECORDS FOR JULY 30
HIGH 99F IN 1949
LOW 51F IN 1956
PRECIP 1.84 INCHES IN 1976
PEAK GUST 70e MPH SW 1944
 
TODAY'S REPORT PREPARED By: Robert Skilling