BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, JULY 30, 2009
ALL TIMES ARE IN EASTERN STANDARD TIME
 
MORNING THUNDERSTORM BRINGS BRIEFLY HEAVY RAIN
PARTIAL CLEARING BY EARLY AFTERNOON WITH A
THREAT OF SHOWERS CONTINUES WITH HIGH HUMIDITY
 
A diminishing line of showers and a thunderstorm
left about one quarter of an inch of rain during
mid-morning today.  Very humid conditions have
continued yesterday and today with dew point
temperatures in the low 70's.  Our overnight low
was a very warm and humid 71F this morning.  
 
Today's observations:
 
7 A.M.  
Weather: Scattered variable broken stratus,
overcast stratocumulus with breaks in overcast  
Temperature: 74F, Dew point: 71F, Wind: SSW at 10 kts
Sea-level pressure: 29.78 inches Hg, rising
Visibility: 10 miles, 15 miles northeast, thin fog
6-hour precipitation:  trace
24-hour precipitation: trace
6-hour minimum temp: 71F
BHO SA 1155 6V SCT E23 OVC 10 086/74/71/2010/978/
6 SCTVBKN CIG RGD BINOVC THN FG ALQDS VSBY NE 15/
8/6// 53012 MANUAL 6000/ 10074 20071
 
10 A.M.
Weather: Overcast nimbostratus, thunderstorm heavy rain shower,
fog, thunderstorm began 9:25 a.m. W-NW moving east,
occasional lightning in cloud, cloud to cloud and cloud to ground 
Temperature: 73F, Dew point: 72F, Wind: W at 5 kts
Sea-level pressure: 29.81 inches Hg, rising
Visibility: 2 miles, 1 mile W-N, 5 miles E-SW
3-hourly precipitation: 0.13 inch   
BHO SA 1455 E12 BKN 20 BKN 65 OVC 2TRW+F 094/73/72/2605/981/
TB25 W-NW MOVG E OCNL LTGICCCCG WNW-NW VSBY W-N 1 E-SW 4
RE10B45/ 8/9// 53008 MANUAL 6013/ ASOS 60012
 
1 P.M.  
Weather: Scattered cumulus, broken cumulus, moderate cumulus  
Temperature: 80F, Dew point: 72F, Wind: W at 7 kts,
Wind: direction variability SW to WNW 
Sea-level pressure: 29.82 inches Hg, rising
Visibility: 35 miles, 45 miles to WNW, light haze   
6-hourly max. temp: 81F
6-hourly precipitation: 0.25 inch
BHO SA 1755 20 SCT E42 BKN 35 097/80/72/2707/982/
MDT CU ALQDS VSBY WNW 45 LGT HZ ALQDS WND 22V30/
8/200 53003 ASOS 60024 MANUAL 6025/ 10081 20074
 
WEATHER SUMMARY FOR WEDNESDAY JULY 29
 
TEMPERATURE (DEGREES F)
MAX.....82    NORMAL.....82
MIN.....69    NORMAL.....63
MEAN....76    NORMAL.....72
 
DEPARTURE FROM 30-YEAR AVERAGE..........+4
TOTAL DEPARTURE FOR THE MONTH..........-95  [-3.5 DEGREES/DAY]
 
HEATING DEGREE DATA WILL RESUME IN SEPTEMBER
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............29 S   AT   6:53 P.M. * 
                   AEROVANE..............29 S   AT   6:53 P.M.   
                   ASOS..................28 S   AT   3:32 P.M.          
                   DAVIS.................29 S   AT   3:31 P.M. 
FASTEST MILE FOR YESTERDAY...............20 S   AT   3:19 P.M.     
MAXIMUM 2-MINUTE ASOS AVERAGE............21 S   AT   3:20 P.M.     
MAXIMUM 2-MINUTE DAVIS AVERAGE...........20 S   AT   3:20 P.M.    
AVERAGE WIND SPEED AND DIRECTION.......13.0 S
                   ASOS................12.7  
                   DAVIS...............11.8 S [180 DEG]
 
* last of several occurrences....
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....trace DEPARTURE....-0.12
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........6.87  DEPARTURE....+3.49
                         ASOS..............7.01
TOTAL PRECIPITATION FOR THE YEAR..........30.51  DEPARTURE....+1.46
                         ASOS.............31.66
 
PRELIMINARY CLIMATE SUMMARY FOR JULY 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
 
7/1  62/57/60/-10/0.51/000/00   25 NNE   TSTM
7/2  66/56/61/-9/1.00/000/00    29 SSW   TSTM
7/3  75/58/67/-3/T/283/31       23 WSW
7/4  77/59/68/-2/0/838/92       43 W      
7/5  78/54/66/-5/0/856/94       33 W     
7/6  79/60/70/-1/0/883/97       20 SSE
7/7  66/58/62/-9/0.73/027/03    28 SE    TSTM
7/8  67/56/62/-9/0.23/091/10    27 NNE   TSTM
7/9  66/55/61/-10/0/689/76      23 NE
7/10 76/54/65/-6/0/896/99       21 SW
7/11 77/56/67/-5/0.29/686/76    36 S
7/12 78/60/69/-3/0.33/650/72    30 SSW   TSTM
7/13 76/55/66/-6/0/802/89       32 SW 
7/14 75/56/66/-6/0/567/63       25 WNW
7/15 79/55/67/-5/0/826/92       30 WSW
7/16 77/62/70/-2/T/161/18       30 S
7/17 86/65/76/+4/0.01/582/65    24 ESE
7/18 84/66/75/+3/0.35/447/50    25 SSW   TSTM
7/19 80/62/71/-1/0/865/97       27 WSW
7/20 80/64/72/0/0/481/54        16 E
7/21 66/61/64/-8/0.62/000/00    29 NNE
7/22 77/61/69/-3/T/160/18       15 W
7/23 72/60/66/-6/0.68/195/22*   35 NE
7/24 69/60/65/-8/2.07/088/10*   46 NE    AERO 45 NE
7/25 83/61/72/-1/0/766/87       30 SSE
7/26 82/68/75/+3/0.05/422/48    32 S     
7/27 83/69/76/+4/0/588/67       30 S     TSTM (no rain, (12-1AM)
7/28 86/67/77/+5/0/709/81       24 S
7/29 82/69/76/+4/0/070/08       29 S
 
7/30 our morning low temp: 71F; the normal low is now 63F
 
NEW DAILY RECORDS FOR JULY 2009 TO DATE...
7/24: New record peak gust 46 MPH NE at 3:32 A.M.
      surpasses previous record of 43 MPH S IN 2008
 
DAILY EXTREMES
 
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR JULY 30
HIGH 99F IN 1949
LOW 51F IN 1956
PRECIP 1.84 INCHES IN 1976
PEAK GUST 70e MPH SW 1944
 
RECORDS FOR JULY 31
HIGH 95F IN 1917
LOW 50F IN 1895,1918
PRECIP 1.34 INCHES IN 1892
PEAK GUST 43e MPH WNW IN 1953, 43 SW IN 1971
 
TODAY'S REPORT PREPARED BY: Robert Skilling