BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, AUGUST 21, 2007 
ALL TIMES ARE IN EASTERN STANDARD TIME 

VERY DRY AIR WITH DEWPOINTS IN MID-40'S EARLY THIS AFTERNOON
AUGUST TEMPERATURE AVERAGE NOW JUST ABOUT ON THE NORMAL
AN UNUSUALLY DRY MONTH WITH RAINFALL DEFICIT NEAR 2 INCHES 

The airmass has become even drier today as winds shifted from 
northeast to east and dewpoints dropped from the 50's this 
morning down to the middle 40' by early this afternoon. 

Three days of cool weather averaging 7 degrees below normal 
in temperature have lowered the monthly mean to within a 
fraction of a degree of normal. 

The lack of rainfall is the main weather highlight of August's weather. 
Just 0.63 inch of rainfall through the first three weeks of the
month leaves us 2 inches drier than normal for the month and one inch
short for the year. 

The big high pressure system which has been bringing us all the 
cool weather also brought the highest barometric reading of the
summer reaching 30.29 inches late this morning. 

Today's observations:

7 A.M. 
Weather: High thin broken cirrus clouds, stratus distant E-S-SW 
Temperature: 60F, Dew point: 56F, Wind: NE at 6 kts 
Wind: Veering gradually past hour 
Sea-level pressure: 30.27 inches Hg, rising
Visibility: 15 miles, 20 N, 30 NE, 12 S-W, thin fog,
thin smoke layer along horizon S-NW 
6-hour min temp: 56F
BHO SA 1155 250 –BKN 300 –BKN 15 249/60/56/0506/027/ 
STRA DSNT E-S-SW AC SE-SW FEW DENSE CI DSNT SW THN F ALQDS 
VSBY N 20 NE 30 S-W 12 THN K LYR ALG HRZN S-NW WND GRDLY VEERING/ 
8/632 51009 10060 20056 

10 A.M. 
Weather: Scattered stratocumulus, overcast dense high cirrus, break in 
the overcast distant ESE-SE 
Temperature: 66F, Dew point: 51F, Wind: E at 11 kts 
Wind: Variabile NNE-ESE
Sea-level pressure: 30.28 inches Hg, rising
Visibility: 50 miles 
BHO SA 1455 32 SCT 130 SCT E200 OVC 50 252/66/51/0811/028/ 
SC FEW MDT CUFRM TOPS AC LYR SSE-SSW DENS CI ALQDS BINOVC
DSNT ESE-SE WND 03V12/ 8/572 53004 

1 P.M. 
Weather: High dense cirrus overcast with scattered altocumulus below
and cumulus and few moderate cumulus, break in overcast NW-NE 
Temperature: 67F, Dew point: 47F, Wind: E at 10 kts
Wind: Variability ENE-ESE 
Sea-level pressure: 30.27 inches Hg, falling
Visibility: 60 miles, 70 NW 
6-hour max. temp. 68F 
BHO SA 1755 150 SCT E200 OVC 60 249/67/47/0910/027/ CU/FEW MDT CU ALQDS
FEW LWR AC S DENS CI ALQDS BINOVC NW-NE VSBY NW 70/ 8/272 58003 10068 20060 

WEATHER SUMMARY FOR MONDAY, AUGUST 20

TEMPERATURE (DEGREES F)
MAX.....70 NORMAL.....79 
MIN.....56 NORMAL.....61
MEAN....63 NORMAL.....69
DEPARTURE FROM 30-YEAR NORMAL.........-6
TOTAL DEPARTURE FOR THE MONTH........+10 (+0.3 DEGREES/DAY)

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..............21 ENE AT 11:24 A.M. 
                   AEROVANE...............17 ENE AT 11:24 A.M. 
                   ASOS...................N/A #
                   DAVIS..................19 ENE AT 11:24 A.M. 
FASTEST MILE FOR YESTERDAY................13 NE AT 11:24 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE.............N/A # 
MAXIMUM 2-MINUTE DAVIS AVERAGE............13 NE AT 11:24 A.M. 
AVERAGE WIND SPEED AND DIRECTION..........7.4 NNE 
                   ASOS...................N/A #
                   DAVIS..................N/A

# 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.....-0.13
                         ASOS..............0.00 
TOTAL PRECIPITATION FOR THE MONTH..........0.62 DEPARTURE.....-1.95 
                         ASOS..............0.55 
TOTAL PRECIPITATION FOR THE YEAR..........30.98 DEPARTURE.....-1.00 
                         ASOS.............30.22 

PRELIMINARY CLIMATE SUMMARY FOR AUGUST 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 
8/1 84/67/76/+4/0/851/98 	20 NNE 
8/2 92/68/80/+8/0/823/95 	21 S 
8/3 92/70/81/+9/0/760/88 	28 SSW
8/4 89/71/80/+8/0/827/96 	29 WSW 
8/5 80/62/71/-1/0/842/98 	23 SSE 
8/6 77/61/69/-3/0.05/129/15 	36 SSE Aero 34 MPH SSE TSTM 
8/7 82/67/75/+4/0.12/410/48 	15 SSE 
8/8 88/70/79/+8/0.10/349/41 	36 S
8/9 75/60/68/-3/0/722/85 	32 NW
8/10 63/53/58/-13/0.19/017/02 16 SSW
8/11 83/52/68/-3/0/743/88 	21 WNW
8/12 86/64/75/+4/0/665/79 	21 SSW
8/13 83/64/74/+3/0.01/260/31 	30 NW TSTM 
8/14 78/58/68/-2/0/812/97 	23 NW
8/15 83/59/71/+1/0/651/78 	36 SSW Aero 34 MPH SSW
8/16 87/67/77/+7/0/641/77 	33 SSW
8/17 78/62/70/0/0.07/241/29 	43 S Aero 39 MPH S TSTM 
8/18 71/52/62/-8/0.08/761/92 	46 WNW Aero 42 MPH WNW, Davis 46 MPH WNW TSTM 
8/19 74/51/63/-7/0/619/75 	25 WNW 
8/20 70/56/63/-6/0/.../.. 	21 ENE 
8/21 morning low temp. of 56F; the normal low is now 60 deg.F 

NEW DAILY RECORDS FOR AUGUST 2007: 
8/18 - NEW RECORD PEAK GUST FOR OF 46 MPH WNW; 
the previous record was 39 MPH SW in 1991. 

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated): 

RECORDS FOR AUGUST 21
HIGH 92F IN 1937, 1995
LOW 47F IN 1982
PRECIP 2.84 INCHES IN 1888
PEAK GUST 54 MPH WSW 2004 

RECORDS FOR AUGUST 22
HIGH 90F IN 1939
LOW 42F IN 1894
PRECIP 2.28 INCHES IN 1935
PEAK GUST 44 MPH SSW 1987 

TODAY'S REPORT PREPARED By: Robert Skilling