BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, APRIL 17, 2007   
ALL TIMES ARE IN EASTERN STANDARD TIME
 
INCREASING WINDS FROM THE NORTH...
GUSTS RECORDED OVER 40 MPH...
SNOW MELTING AS IT FALLS
 
Winds are increasing late this morning from the north 
as a new low pressure system intensifies east of Nantucket.
Light drizzle and a brief shower added another tenth of an
inch to the 3-day precipitation total which had reached
3.42 inches as of 8 o'clock this morning.  A brief light
snow shower was observed just after 8 a.m. Snow was falling
with rain but melting as it fell with the temperature around
36 degrees early this afternoon. 

Today's observations:
 
7 A.M.   
Weather: Low overcast, very light drizzle and fog  
Temperature: 35F, Dew point: 34F, Wind: NNW at 15G30 kts
Wind: Peak wind 30 kts NNW at 52 past the hour 
Wind: Variable in direction WNW to N 
Sea-level pressure: 29.40 ins. Hg, steady
Visibility: 5 miles  
6-hour min. 35 deg. 
24-hour rainfall: 0.11 in.   
BHO SA 1155 E6 OVC 5L-F 957/35/34/3415G30/940/ HIER OVC OCNL VSB
AT 11 HND PCPN VRY LGT PK WND 3430/52/ WND 30V01/ 8/7// 50007 
ASOS 60010 MANUAL 6010/ ASOS 70053 MANUAL 70049 10040 20035
 
10 A.M.
Weather: Low overcast, light drizzle and fog   
Temperature: 37F, Dew point: 37F, Wind: NNW at 14G23 kts
Wind: Peak wind NNW @ 28 kts at 31 past the hour
Sea-level pressure: 29.40 inches Hg, falling 
Visibility: 3 miles
3-hourly rainfall: 0.03 inch
3-hourly snowfall: trace 
BHO SA 1455 E7 OVC 3L-F 957/37/37/3414G23/940/ CIG RGD PK WND 3428/31/ 
WND 31V02/ 8/7// 50000 MANUAL 6003/ ASOS 60002 
 
1 P.M.
Weather: Low overcast. light rain, snow and fog 
Temperature: 36F, Dew point: 36F, Wind: NNW at 17G27 kts
Wind: Peak wind N @ 36 kts at 11:57 A.M. 
Sea-level pressure: 29.41 inches Hg, rising
Visibility: 5 miles
6-hourly rainfall: 0.10 inch
6-hourly min. temp. 35 deg.   
BHO SA 1755 E5 OVC 5R-S-F 960/36/36/3417G27/941/ CIG RGD 
PK WND 3536/1657/ 8/7// 53004 ASOS 60008
MANUAL 6010/ 10038 20035 
 
WEATHER SUMMARY FOR MONDAY, APRIL 16 PATRIOTS DAY
 
TEMPERATURE (DEGREES F)
MAX.....50    NORMAL.....56 
MIN.....40    NORMAL.....37
MEAN....45    NORMAL.....46
 
DEPARTURE FROM 30-YEAR NORMAL...........-1
TOTAL DEPARTURE FOR THE MONTH..........-94 (-6.1 DEGREES/DAY) 
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY..........20   DEPARTURE.........+1
TOTAL HEATING UNITS FOR THE MONTH.........432   DEPARTURE........+94 
TOTAL HEATING UNITS FOR THE SEASON.......5426   DEPARTURE.......-377
TOTAL HEATING UNITS LAST SEASON TO DATE..5197   DIFFERENCE......+229
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............73 E  AT  5:14 A.M.   
                   AEROVANE.............73 E  AT  5:14 A.M.  
                   ASOS.................72 E  AT  5:14 A.M.  
                   DAVIS................66 E  AT  5:14 A.M. 
FASTEST MILE FOR YESTERDAY..............54 E  AT  5:15 A.M.     
MAXIMUM 2-MINUTE ASOS AVERAGE...........52 E  AT  5:15 A.M.   
MAXIMUM 2-MINUTE DAVIS AVERAGE..........49 E  AT  5:15 A.M.  
AVERAGE WIND SPEED AND DIRECTION......  25.5 E 
                    ASOS................23.9   
                    DAVIS...............25.2 E [110 deg]
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.49  DEPARTURE.....+0.34
                         ASOS..............0.54
TOTAL PRECIPITATION FOR THE MONTH..........6.21  DEPARTURE.....+3.81  
                         ASOS..............5.94    
TOTAL PRECIPITATION FOR THE YEAR..........17.95  DEPARTURE.....+1.92
                         ASOS.............17.58   
 
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......-1.5 
TOTAL SNOWFALL FOR THE SEASON..............27.6  DEPARTURE.....-31.0  
    
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/.../..          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/.../..          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 morning low temp. 35 deg; normal now 38 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 17
HIGH 93 IN 2002
LOW 21 IN 1908
PRECIP 1.68 IN 1954
SNOWFALL 1.0 IN. IN 1899
PEAK GUST 58 MPH NW IN 1994
 
RECORDS FOR APRIL 18
HIGH 92 IN 1976
LOW 23 1887
PRECIP 1.48 IN 1954
SNOWFALL 3.7 IN. IN 1965
PEAK GUST 59 MPH S IN 1982
 
TODAY'S REPORT By: Bob Skilling