BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
  
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, MAY 20, 2008  
ALL TIMES ARE IN EASTERN STANDARD TIME UNLESS NOTED
 
COOLER THAN NORMAL MAY TEMPERATURES CONTINUE
HIGH IN MID-60'S BEFORE HIGH CLOUDS THICKENED
 
This month continues to run cooler than normal by 
about 2 degrees.  Despite today's high of 64 which 
was about 4 degrees less than average the day will turn 
out 5 degrees below the normal due to a chilly 
42-degree morning low temperature.
Dense high clouds overspread the sky early this after-
noon ahead of an area of showers moving through 
Connecticut and offshore to our south. 
 
Today's observations:
 
8 A.M. EDT
Weather: High thin cirrostratus overcast, clear sky distant NW-NE  
Temperature: 48F, Dew point: 35F,  Wind: SW at 10 kts
Sea-level pressure: 29.61 inches Hg, rising
Visibility: 45 miles
6-hourly min. temp. 42F
24-hourly rainfall: 0.00 inch   
BHO SA 1155 220 SCT 250 –OVC 45 028/48/35/2310/961/ 
BINOVC/CLR SKY BND DSNT NW-E LGT DSNT HZ/ 
8/006 51013 10048 20042 
   
11 A.M. EDT
Weather: High thin scattered cirrus clouds 
Temperature: 58F, Dew point: 35F,  Wind: SSW at 11 kts 
Wind: direction variable S-WSW  
Sea-level pressure: 29.59 inches Hg, falling
Visibility: 55 miles 
BHO SA 1455 250 –SCT 300 –SCT 55 020/58/35/2111/959/ 
FEW SML CU DSNT NNW FEW AC S-SW DENS CI LYR SE-SW 
WND 18V24/ 8/142 58008
 
2 P.M. EDT
Weather: Broken dense cirrus clouds, high cirrus overcast,
partly thin overhead through north and northeast 
Temperature: 61F, Dew point: 34F,  Wind: SSW at 13G21 kts
Wind: peak gust 33 kts SW at 54 mins. past the hour,
Wind: direction variable SSW-W  
Sea-level pressure: 29.50 inches Hg, falling
Visibility: 60 miles 
6-hourly max. temp: 64F    
BHO SA 1755 200 SCT E220 BKN 250 OVC 60 991/61/34/2113G21/950/ 
CU WNW-N AC CHAOTIC SKY/FEW ACSL ALQDS DENS CI ALQDS OVC PTLY 
THN OVHD-N-NE WND 17V25/ 8/192 58029 10064 20048  
 
WEATHER SUMMARY FOR MONDAY, MAY 19
 
TEMPERATURE (DEGREES F)
MAX.....59    NORMAL.....68
MIN.....44    NORMAL.....48
MEAN....52    NORMAL.....58
 
DEPARTURE FROM 30-YEAR NORMAL............-6  
TOTAL DEPARTURE FOR THE MONTH...........-37 [-2.1 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............13  DEPARTURE........+5
TOTAL HEATING UNITS FOR THE MONTH...........226  DEPARTURE.......+28 
TOTAL HEATING UNITS FOR THE SEASON.........5837  DEPARTURE......-387 
TOTAL HEATING UNITS LAST SEASON TO DATE....5797  DIFFERENCE......+40
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............46 W   AT  4:52 P.M.   
                   AEROVANE.............44 W   AT  4:52 P.M.     
                   ASOS.................47 W   AT  4:52 P.M.  
                   DAVIS................46 WSW AT  4:51 P.M.  
FASTEST MILE FOR YESTERDAY..............34 W   AT  5:14 P.M. *    
MAXIMUM 2-MINUTE ASOS AVERAGE...........35 W   AT  5:14 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE..........36 W   AT  5:14 P.M.     
                   AVERAGE............19.6 WSW     
                   ASOS...............18.5    
                   DAVIS..............19.1 WSW [250 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..........1.65   DEPARTURE......-0.68
                         ASOS..............1.58
TOTAL PRECIPITATION FOR THE YEAR..........22.41   DEPARTURE......+2.13
                         ASOS.............24.81 #
# Includes erroneous ASOS precipitation data on 2/13/08.
 
PRELIMINARY CLIMATE SUMMARY FOR MAY 2008 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, records not finalized
 
5/1  60/35/48/-4/0/786/93        30 W    Aero 28 MPH W
5/2  48/42/45/-7/0.07/000/00     21 ENE
5/3  43/41/42/-11/0.09/000/00    25 E    
5/4  50/42/46/-7/0.17/000/00     27 E
5/5  69/40/55/+2/0/752/88        24 ESE  
5/6  74/46/60/+6/0/686/80        25 W
5/7  75/48/62/+8/0/722/84        29 S
5/8  75/54/65/+11/0.08/172/20    42 W    Aero 42 MPH W 
5/9  56/43/50/-5/0.26/000/00     30 NE
5/10 57/44/51/-4/T/407/47        35 NNE  
5/11 58/41/50/-5/0/747/86        24 ENE  
5/12 47/42/45/-11/0/017/02       43 NNE  Aero 43 MPH NNE
5/13 63/43/53/-3/0/812/93        47 NNE  Aero 50 MPH NNE
5/14 64/47/56/-1/0/788/90        23 ENE
5/15 67/47/57/0/T/009/01         22 S  
5/16 59/45/52/-5/0.49/009/01     21 ENE
5/17 72/46/59/+2/0.47/449/51     33 W
5/18 71/50/61/+3/0.02/494/56     30 S
5/19 59/44/52/-6/0/566/64        46 W    Aero 44 MPH W  
 
5/20 morning low temp. 42F; our normal low is now 48F
 
NEW DAILY RECORDS FOR MAY 2008
None to date.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
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
 
RECORDS FOR MAY 21
HIGH 92F IN 1921
LOW 35F IN 1907
PRECIP 1.61 INS IN 1954
PEAK GUST 74 MPH WSW IN 2006
 
TODAY'S REPORT PREPARED By: Robert Skilling