BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, APRIL 20, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME
 
CLEAR AND VERY SUNNY TODAY AFTER A WEEK OF 
OVERCAST VERY WET COOL AND GLOOMY WEATHER
FIVE-DAY FINAL RAINFALL TOTAL 4.39 INCHES
 
Except for a few high thin cirrus clouds today is 
that sunny day we've all been waiting for after 
a five day nor'easter ended yesterday morning. 
The storm began with some snow mixed with the rain
on April 15th and ended with a little sleet mixed 
with rain yesterday morning, April 19th.  The final
precipitation total for five consecutive days of 
rainfall was 4.39 inches. Rainfall for the month has
now topped 7 inches.
 
Temperatures continue cooler than normal today as the
northeast wind still persists;  the month remains 
at 6.3 degrees colder than normal.  The 24-hour corrected
mean temperature for the month is 37.5 degrees.
 
Today's observations:
 
7 A.M.   
Weather: High thin scattered cirrus 
Temperature: 42F, Dew point: 16F, Wind: N at 17G26 kts
Wind: Peak wind 27 kts N at 17 past the hour 
Wind: Variable in direction NW to NNE
Sea-level pressure: 30.06 ins. Hg, rising
Visibility: 75 miles 
6-hour min. 36 deg. 
24-hour rainfall: trace
24-hour snowfall: trace [sleet]   
BHO SA 1155 250 –SCT 300 –SCT 75 179/42/16/0117G26/006/ 
FEW CC PK WND 3627/17/ WND 32V04/ 8/001 53016 10042 20036 
 
10 A.M.
Weather: Clear, few cirrus  
Temperature: 48F, Dew point: 19F, Wind: NNE at 12 kts
Wind: Variable in direction NNW to ENE 
Sea-level pressure: 30.10 inches Hg, steady 
Visibility: 80 miles 
BHO SA 1455 CLR 80 193/48/19/0212/010/ FEW CI WND 34V07/
8/001 51014
 
1 P.M.
Weather: Clear, few cirrus   
Temperature: 53F, Dew point: 16F, Wind: NE at 8 kts
Wind: Variability N TO ENE  
Sea-level pressure: 30.09 inches Hg, falling 
Visibility: 75 miles
BHO SA 1755 CLR 75 191/53/16/0408/009/ FEW CI WND 01V07/
8/001 58002 10053 20042 
   
WEATHER SUMMARY FOR THURSDAY, APRIL 19
 
TEMPERATURE (DEGREES F)
MAX.....49    NORMAL.....56 
MIN.....36    NORMAL.....38
MEAN....43    NORMAL.....47
 
DEPARTURE FROM 30-YEAR NORMAL...........-4
TOTAL DEPARTURE FOR THE MONTH.........-116 (-6.3 DEGREES/DAY) 
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY..........22   DEPARTURE.........+4
TOTAL HEATING UNITS FOR THE MONTH.........508   DEPARTURE.......+115 
TOTAL HEATING UNITS FOR THE SEASON.......5502   DEPARTURE.......-355
TOTAL HEATING UNITS LAST SEASON TO DATE..5232   DIFFERENCE......+270
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............38 NE  AT 12:26 P.M.    
                   AEROVANE.............35 NE  AT 12:26 P.M. 
                   ASOS.................37 NE  AT 12:26 P.M.  
                   DAVIS................34 ENE AT 11:47 A.M. 
FASTEST MILE FOR YESTERDAY..............25 NE  AT 11:49 A.M.       
MAXIMUM 2-MINUTE ASOS AVERAGE...........25 NE  AT 11:48 A.M.    
MAXIMUM 2-MINUTE DAVIS AVERAGE..........24 NE  AT 12:26 P.M.   
AVERAGE WIND SPEED AND DIRECTION........13.5 NNE  
                    ASOS................13.8  
                    DAVIS...............13.5 NNE [030 deg]
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...trace  DEPARTURE.....-0.14
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........7.18  DEPARTURE.....+4.36  
                         ASOS..............6.85    
TOTAL PRECIPITATION FOR THE YEAR..........18.92  DEPARTURE.....+2.47
                         ASOS.............18.49   
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M........trace  DEPARTURE......-0.1
TOTAL SNOWFALL FOR THE MONTH................0.2  DEPARTURE......-1.8 
TOTAL SNOWFALL FOR THE SEASON..............27.6  DEPARTURE.....-31.3  
    
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/.../..          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
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 morning low temp. 36 deg; normal low now 39 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.       
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR APRIL 20
HIGH 88 IN 1927
LOW 18 IN 1897
PRECIP 1.14 IN 1972
SNOWFALL 2.5 IN. IN 1904, 1972
PEAK GUST 76 MPH WNW IN 1963
 
RECORDS FOR APRIL 21
HIGH 85 IN 1923
LOW 22 IN 1908
PRECIP 3.18 IN. IN 1991 
SNOWFALL 0.8 IN. IN 1947
PEAK GUST 76e MPH NE IN 1940
 
TODAY'S REPORT By: Robert Skilling/Stephanie Radner