BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, MAY 1, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME
 
APRIL 2007 AT THE OBSERVATORY....
 
Av. Max. 52.0
Av. Min. 36.0
Mean temp: 44.0 [-2.3]
Mean temp: (corr. to 24 hours) 43.6 deg. 
HDD = 622 [+60] 
Season = 5616 [-410]
CDD  = 2 [- 1]
Season = 2 [- 2]
Precip: 8.68 [+4.36]
Greatest in 24 hours: 3.31 ins. [15-16]
Days with measurable precip: 16
Snowfall: 0.2 [-2.9 ] 
Season: 27.6 [-32.4] 
Av. wind speed [corr.] 13.6 MPH 
Prevailing direction: W 16%
Peak gust: 73 MPH E [16TH]  
Sunshine: 162.4 [corrected hrs.] or 40% of possible 
Av. vapor pressure: 6.2 mbs. 
 
Today's observations:
 
7 A.M.   
Weather: High very thin overcast, breaks east thru south 
Temperature: 49F, Dew point: 30F, Wind: W at 10 kts 
Wind: gust to 21 kts pst hour   
Sea-level pressure: 29.95 inches Hg, rising 
Visibility: 90-100 miles 
6-hour min. 44F   
24-hour rainfall: 0.06   
BHO SA 1155 300 –OVC 90 141/49/30/2710/995/ FEW LWR CI BINOVC E-S 
VSBY PSBL 100 MILES GST 21 KTS PST HR/ 8/001 53023 MANUAL 70006 
ASOS 70005 10049 20044 
 
10 A.M.
Weather: High thin overcast with patches dense cirrus 
Temperature: 58F, Dew point: 25F, Wind: W at 11G18 kts 
Sea-level pressure: 29.95 Hg, steady  
Visibility: 90 to 100 miles
BHO SA 1455 220 SCT 250 –BKN 300 –OVC 90 142/58/25/2811G18/995/
PTCHS DENS CI VSBY PSBL 100 MILES WND 25V32/ 8/002 51001 
 
1 P.M.
Weather: Broken dense and thin high clouds  
Temperature: 64F, Dew point: 25F, Wind: W at 10G20 kts 
Sea-level pressure: 29.92 inches Hg, falling 
Visibility: 90-100 miles 
6-hourly max. temp. 64 deg. 
BHO SA 1755 E220 BKN 250 BKN 90 133/64/25/2710G20/992/
FEW ACSL W-N DENSE CI ALQDS VSBY PSBL 100 MILES WND 24V31/ 
8/002 58009 10064 20049  
 
 
WEATHER SUMMARY FOR MONDAY, APRIL 30
 
TEMPERATURE (DEGREES F)
MAX.....70    NORMAL.....61 
MIN.....42    NORMAL.....42
MEAN....56    NORMAL.....52
DEPARTURE FROM 30-YEAR NORMAL...........+4
TOTAL DEPARTURE FOR THE MONTH..........-59 (-2.3 DEGREES/DAY) 
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............9  DEPARTURE.........-5
TOTAL HEATING UNITS FOR THE MONTH......... 622  DEPARTURE........+60 
TOTAL HEATING UNITS FOR THE SEASON........5616  DEPARTURE.......-410
TOTAL HEATING UNITS LAST SEASON TO DATE...5419  DIFFERENCE......+197
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............44  WSW AT 3:03 P.M.
                   AEROVANE.............46  WNW AT 4:41 P.M.  
                   ASOS.................41  WNW AT 6:09 P.M. 
                   DAVIS................45  WSW AT 3:03 P.M.  
FASTEST MILE FOR YESTERDAY..............34  WNW AT 6:11 P.M.  
MAXIMUM 2-MINUTE ASOS AVERAGE...........32  W   AT 3:26 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..........34  W   AT 3:26 P.M.  
AVERAGE WIND SPEED AND DIRECTION.......16.7 S 
                    ASOS...............17.2     
                    DAVIS..............15.0 W [260 degrees] 
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.06   DEPARTURE....-0.07
                         ASOS..............0.05
TOTAL PRECIPITATION FOR THE MONTH..........8.68   DEPARTURE.....+4.36 
                         ASOS..............8.33    
TOTAL PRECIPITATION FOR THE YEAR..........20.42   DEPARTURE.....+2.47
                         ASOS.............19.97   
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE......-0.1
TOTAL SNOWFALL FOR THE MONTH................0.2  DEPARTURE......-2.9 
TOTAL SNOWFALL FOR THE SEASON..............27.6  DEPARTURE.....-32.4  
    
PRELIMINARY CLIMATE SUMMARY FOR APRIL 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
 
4/1  59/33/46/+5/0.42/0/511/67       30 S
4/2  39/35/37/-5/0.33/0/000/00       27 E
4/3  41/32/37/-5/0.04/0/000/00       28 ENE
4/4  36/32/34/-8/0.90/0.2/000/00     38 E
4/5  43/26/35/-8/0.21/T/163/21       36 WSW
4/6  39/23/31/-12/0/0/590/76         36 WSW
4/7  40/26/33/-10/0/0/405/52         35 W
4/8  40/25/33/-11/0/0/619/79         44 W      Aero 42 MPH W
4/9  50/30/40/-4/0/0/746/95          36 W
4/10 43/30/37/-7/0/0/158/20          28 W 
4/11 51/28/40/-5/0/0/712/90          22 SSE
4/12 39/32/36/-9/0.89/T/000/00       42 E      Aero 40 MPH E
4/13 47/31/39/-6/0/0/096/12          41 W      Aero 42 MPH W
4/14 52/35/44/-2/0/0/392/49          37 W
4/15 44/35/40/-6/1.75/T/000/00       66 E      Aero 64 MPH E  
4/16 50/40/45/-1/1.56/0/000/00       73 E      Aero 73 MPH E 
4/17 40/35/38/-9/0.69/T/000/00       54 NNE    Aero 53 MPH NNE
4/18 39/36/38/-9/0.37/0/000/00       43 N
4/19 49/36/43/-4/0.02/T/285/35       38 NE     Aero 35 MPH NE 
4/20 57/36/47/-1/0/0/815/100         31 N
4/21 74/45/60/+12/0/0/753/92         24 NW
4/22 75/50/63/+14/0/0/779/95         31 SSE     
4/23 85/49/67/+18/0/0/675/82         42 S      Davis 45 MPH S 
4/24 73/50/62/+13/0/0/586/71         39 W      Aero  41 MPH W
4/25 58/43/51/+1/0.23/0/083/10       27 WNW 
4/26 62/39/51/+1/0/0/656/79          30 SSE    Aero  28 SSE
4/27 48/42/45/-5/1.09/0/000/00       25 E
4/28 68/43/56/+5/0.10/0/293/35       17 S   
4/29 49/42/46/-5/0.02/0/000/00       17 NNE
4/30 70/42/56/+4/0.06/0/429/51       44 WSW    Aero 46 MPH WNW
 
5/1  morning low temp. 44 deg; normal now 42 deg.
 
NEW DAILY RECORDS FOR APRIL SO FAR....
 
4/15 - NEW RECORD HIGH PEAK WIND GUST FOR THIS DATE OF 66 MPH E; the previous
record was 59 mph estimated from the S in 1946 and measured from the S in 1980.
NEW RECORD DAILY RAINFALL OF 1.75 INS.; previous record 1.29 ins. in 1990.
 
4/16 - NEW RECORD HIGH PEAK WIND GUST OF 73 MPH E; the previous record for this
date was 63 mph SSE in 1996.       
 
4/23 - EQUALED RECORD HIGH MAXIMUM TEMPERATURE OF 85 DEGREES set in 1908.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR MAY 1
HIGH 87F IN 1899
LOW 29F IN 1978
PRECIP 2.53 INCHES IN 1921
SNOWFALL TRACE IN 1905,1917,1921,1995.
PEAK GUST 57 MPH NW IN 1974
 
RECORDS FOR MAY 2
HIGH 92F IN 2001
LOW 29F IN 1903
PRECIP 1.36 INCHES IN 2006
SNOWFALL 1.0 INS IN 1888
PEAK GUST 58 MPH S IN 1983
 
TODAY'S REPORT PREPARED By: Robert Skilling