BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 13, 2009 
ALL TIMES ARE IN EASTERN STANDARD TIME
 
CLEAR SKY GIVES WAY TO CUMULUS CLOUDS
TEMPERATURES REACH THE 70-DEGREE MARK
 
A perfectly clear sky early this morning
was cloud filled by early afternoon with
cumulus but no precipitation was observed.
Temperatures were able to reach 70F before
the sun disappeared behind the cumulus. 
 
Today's observations:
 
7 A.M.  
Weather: Clear, no clouds
Temperature: 55F, Dew point: 41F, Wind: SW at 6 kts,
Sea-level pressure: 30.40 inches Hg, rising
Visibility: 35 miles, 25 miles N-SE, 50 miles W-N 
6-hour minimum temp: 45F
24-hour precipitation: 0.00
BHO SA 1155 CLR 35 294/55/41/2306/040/ THN K ALG HRZN N-NE 
LGT HZ VSYB N-SE 30 W-NW 50/ 51007 10055 20045 
 
10 A.M.  
Weather: Cumulus and moderate cumulus forming, few cirrus south
Temperature: 65F, Dew point: 37F, Wind: S at 4 kts.
Wind: light and variable
Sea-level pressure: 30.42 inches Hg, rising
Visibility: 45 miles, light haze  
BHO SA 1455 CLR 45 302/65/37/1704/042/ CU/MDT CU FRMG ALQDS
FEW CI S LGT HZ WND L/V/ 8/201 51008
 
1 P.M.  
Weather: Broken cumulus, moderate cumulus, altocumulus
generated by cumulus
Temperature: 69F, Dew point: 32F, Wind: S at 8 kts,
Wind: direction variable SE to SSW 
Sea-level pressure: 30.42 inches Hg, falling
Visibility: 45 miles, light haze
6-hour maximum temp: 70F  
BHO SA 1755 E55 BKN 85 BKN 45 301/69/32/1808/042/
MDT CU ALQDS WND 13V20/ 8/260 58001 10070 20055
 
WEATHER SUMMARY FOR TUESDAY, MAY 12
 
TEMPERATURE (DEGREES F)
MAX.....63    NORMAL.....66
MIN.....45    NORMAL.....46
MEAN....54    NORMAL.....56
 
DEPARTURE FROM 30-YEAR NORMAL...........-2
TOTAL DEPARTURE FOR THE MONTH..........+34 [+2.6 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............11  DEPARTURE.......+1
TOTAL HEATING UNITS FOR THE MONTH...........100  DEPARTURE......-38
TOTAL HEATING UNITS FOR THE SEASON.........5996  DEPARTURE.....-168
TOTAL HEATING UNITS LAST SEASON TO DATE....5772  DIFFERENCE....+224
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............22 ENE AT  1:03 P.M. 
                   AEROVANE.............18 SSW AT  4:13 P.M. 
                   ASOS.................20 NE  AT  1:45 P.M.   
                   DAVIS................21 NE  AT 12:55 P.M.  
FASTEST MILE FOR YESTERDAY..............14 ENE AT  1:51 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE...........15 ENE AT  1:51 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE..........15 SSW AT  4:14 P.M.  
AVERAGE WIND SPEED AND DIRECTION...... 7.9 S 
                   ASOS................7.7 
                   DAVIS...............7.5 ENE [060 DEG]
* last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE....-0.12
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.15  DEPARTURE....+0.66
                         ASOS..............2.14 
TOTAL PRECIPITATION FOR THE YEAR..........16.76  DEPARTURE....-2.68
                         ASOS.............17.82 
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE..... 0.0
TOTAL SNOWFALL FOR THE MONTH................0.0  DEPARTURE.....-0.1
TOTAL SNOWFALL FOR THE SEASON..............78.9  DEPARTURE.....18.8 
 
PRELIMINARY CLIMATE SUMMARY FOR MAY 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane recording wind system gust when significant
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
5/1  64/53/59/+7/T/000/00          37 SSW   AERO 37 MPH SSW
5/2  68/52/60/+8/0.05/263/31       32 WNW
5/3  64/48/56/+3/T/068/08          25 S
5/4  64/48/56/+3/0.01/009/01       17 SSW
5/5  52/44/48/-5/0.95/000/00       43 NNE   AERO 40 MPH NNE
5/6  63/43/53/-1/0.40/189/22       24 SSE  
5/7  68/49/59/+5/0.60/009/01       29 S    
5/8  75/52/64/+10/0/690/80         28 S
5/9  71/55/63/+8/0.13/104/12       31 W     TSTM
5/10 65/46/56/+1/0/840/97          53 W     AERO 50 MPH W
5/11 63/41/52/-3/0/781/90          24 WNW
5/12 63/45/54/-2/0/.../..          22 ENE
 
5/13 morning low temp: 45F, our normal low temp. 46F
 
NEW DAILY RECORDS FOR MAY 2009...
NONE
 
DAILY EXTREMES
 
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR MAY 13
HIGH 85F IN 1947
LOW 35F IN 1914, 2005
PRECIP 2.39 INCHES IN 2006
PEAK GUST 49 MPH NNW IN 1965
 
RECORDS FOR MAY 14
HIGH 85F IN 1961
LOW 33F IN 1895
PRECIP 1.93 INCHES IN 2006
PEAK GUST 50e MPH SW IN 1976
 
TODAY'S REPORT PREPARED BY: Robert Skilling