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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 19, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME

COLD, RAINY AND FOGGY AGAIN TODAY...MORE THAN TWO INCHES
OF RAIN SINCE FRIDAY MORNING...  
The high and low temperatures on Friday were 42 and 39,
and the 42 is a new record low maximum temperature for
May 18th, surpassing the previous 48 in 1895 and 1956.
The rainfall that began early on Friday has amounted to 
2.33 inches through 7 AM this morning, with additional 
light rain and drizzle after that time. The calendar day 
rainfall for Friday has not yet been finalized, but it 
will be about 1.90 inches.  This will also set a new 
record for May 18th, surpassing 1.58 inches in 2002.
  
Today's observations:

7 A.M.   
Weather: Sky obscured in light rain, light drizzle and fog  
Temperature: 42F, Dew point: 42F, Wind: NNW at 8 kts 
Sea-level pressure: 29.91 inches Hg, steady   
Visibility: 1/8 mile    
24-hourly precip: 1.73 inch
6- hourly min temp. 39 deg.  
BHO SA 1155 W3 X 1/8R-L-F 130/42/42/3308/991/ WND LGT/ 8//// 
55000 60/// 70173 10042 20040

10 A.M.
Weather: Sky partly obscured with light rain, light drizzle
and fog, overcast nimbostratus   
Temperature: 46F, Dew point: 46F, Wind: NW at 4 kts 
Sea-level pressure: 29.92 inches Hg, rising   
Visibility: 1 mile, variable 1/2 to 11/2 miles  
3-hourly rainfall: 0.07 in. 
BHO SA 1455 –X E2 OVC 1VR-L-F 133/46/46/3104/992/ F5 VSBY 
1/2V11/2 WND LGT/ 8/6// 53003 6007/
   
1 P.M.
Weather: Sky partly obscured with light rain, light drizzle
and fog, overcast nimbostratus 
Temperature: 49F, Dew point: 48F, Wind: NW at 4 kts 
Sea-level pressure: 29.91 inches Hg, falling   
Visibility: 11/2 miles, variable 102 miles     
Six hourly max. temp: 49 deg.
Six-hourly rainfall: 0.10 in. 
BHO SA 1755 –X E3 OVC 11/2VR-L-F 130/49/48/3004/991/ F4 VSBY 
1V2 WND LGT/ 8/6// 56003 6010/ 10049 20042

WEATHER SUMMARY FOR FRIDAY, MAY 18  

TEMPERATURE (DEGREES F)
MAX.....42    NORMAL.....68 
MIN.....39    NORMAL.....48
MEAN....41    NORMAL.....58
DEPARTURE FROM 30-YEAR NORMAL..........-17
TOTAL DEPARTURE FOR THE MONTH..........+35 (+1.7 DEGREES/DAY)
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY...........24  DEPARTURE........+16
TOTAL HEATING UNITS FOR THE MONTH..........160  DEPARTURE........-30  
TOTAL HEATING UNITS FOR THE SEASON........5776  DEPARTURE.......-440
TOTAL HEATING UNITS LAST SEASON TO DATE...5645  DIFFERENCE......+131  

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............37 NNE AT 10:48 A.M. *
                   AEROVANE.............36 NNE AT 10:48 A.M.
                   ASOS.................33  NE AT 10:53 A.M.
                   DAVIS................35 NNE AT 10:46 A.M.
FASTEST MILE FOR YESTERDAY..............26 NNE AT 10:48 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE...........23 NNW AT  6:58 P.M. 
MAXIMUM 2-MINUTE DAVIS AVERAGE..........24 NNE AT 10:50 A.M.
AVERAGE WIND SPEED AND DIRECTION.......15.5 N
                   ASOS................15.9
                   DAVIS...............15.2 NNE [016 deg]
* last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....1.73  DEPARTURE.....+1.61
                         ASOS..............1.72  
TOTAL PRECIPITATION FOR THE MONTH..........2.99  DEPARTURE.....+0.78 
                         ASOS..............2.91    
TOTAL PRECIPITATION FOR THE YEAR..........23.41   DEPARTURE....+3.25
                         ASOS.............22.88    
 
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..............27.6  DEPARTURE.....-32.5  
    
PRELIMINARY CLIMATE SUMMARY FOR MAY 2007......CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST

AERO: Aerovane recording wind system when significant
TSTM: Thunderstorm day
....: Data not yet available
 
5/1  67/44/56/+4/0/0/624/74      33 NW 
5/2  64/45/55/+3/0.06/0/381/45   36 NW    Aero 33 MPH WNW
5/3  67/42/55/+2/0/0/849/100     38 W     Aero 37 MPH W
5/4  66/44/55/+2/0/0/842/99      39 WNW   Aero 40 MPH WNW 
5/5  65/45/55/+2/0/0/384/45      33 N  
5/6  51/42/47/-7/T/0/514/60      36 N     Aero 33 MPH N 
5/7  68/39/54/0/0/0/798/93       25 S
5/8  77/43/60/+6/0/0/851/99      33 S     Aero 31 MPH S 
5/9  85/54/70/+15/0/0/707/92     30 S 
5/10 85/60/73/+18/0/0/692/80     29 S     Aero 27 MPH S
5/11 74/60/67/+12/0.02/0/355/41  23 S
5/12 63/47/55/-1/0.02/0/469/54   32 NE    
5/13 65/46/56/0/T/0/775/89       33 WNW   Aero 33 MPH WNW 
5/14 73/43/58/+1/0/0/822/94      30 SSW
5/15 80/50/65/+8/0.01/0/210/24   30 S     TSTM evening   
5/16 66/44/55/-2/0.54/0/527/60   40 NW    TSTM P.M.  
5/17 50/42/46/-11/0.01/0/.../..  28 NE  
5/18 42/39/41/-17/.../0/0/0      37 NNE

5/19 morning low temp. 40 deg; normal now 48 deg.       

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR MAY 19
HIGH 91F IN 1962
LOW 34F IN 2002
PRECIP 1.54 INCHES IN 1900
PEAK GUST 58 MPH NW IN 1964

RECORDS FOR MAY 20
HIGH 91F IN 1975,1996
LOW 37F IN 1948, 2002
PRECIP 1.65 INCHES IN 1969
PEAK GUST 57 MPH S IN 1963, WNW IN 1982

TODAY'S REPORT PREPARED By: Mike Iacono 

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