BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, APRIL 28, 2009 
ALL TIMES ARE IN EASTERN STANDARD TIME 
 
LATE APRIL HEAT RETURNS FOR ANOTHER DAY
LOW OF 58F WOULD BE RECORD HIGH MINIMUM
 
The 80-degree late April heat has returned today
after a one day break yesterday when our high
reading was 72F. Today's record high of 92F set
in 1990 may be difficult to approach or surpass
but our temperature had reached at least 90F
by shortly after 1 P.M. EDT. Today is likely the
first 90-degree day to occur during April since
a reading of 93F on April 17, 2002. A good jumping
off spot for today's heat was the morning low temp-
erature of 58F which would be a new record high
minimum should it hold through midnight.  
As of 2 p.m. EDT the maximum temperature has been
91.1F in the Hazen shelter or still one short of
today's record. The air is extremely dry with a
relative humidity of 22%. 
 
Today's weather observations: 
 
7 A.M.
Weather: Clear, few cirrus, cirrus layer W-N
Temperature: 67F, Dew point: 52F, Wind: SSW at 13 kts
Sea-level pressure: 30.15 inches Hg, steady
Visibility: 25 miles, hazy
6-hour minimum temperature: 58F
24-hour precipitation: 0.00
BHO SA 1155 CLR 25 209/67/52/2113/015/ FEW CI AND CI LAYR W-N
HAZY/ 8/001 58000 10067 20058 
 
10 A.M. 
Weather: Thin scattered cirrus  
Temperature: 83F, Dew point: 50F, Wind: SSW at 12 kts,
Wind: Direction variable S-WSW
Sea-level pressure: 30.12 inches Hg, falling
Visibility: 30 miles, hazy
BHO SA 1455 250 –SCT 300 –SCT 30 201/83/50/2112/012/ HAZY/ 8/001
58008
 
1 P.M.  
Weather: Thin broken cirrus, few small cumulus forming
distant W-N 
Temperature: 91F, Dew point: 48F, Wind: SSW at 16G26 kts,
Wind: Direction variable S-WSW,
Wind: Peak wind 31 kts S at 12:37 p.m. 
Sea-level pressure: 30.02 inches Hg, falling
Visibility: 35 miles, 45 miles WNW, hazy
6-hour max. temp: 91F 
BHO SA 1755 250 –SCT 300 –BKN 35 165/91/48/2016G26/002/
FEW SML CU FRMG DSNT W-N HAZY PK WND 1931/37/
8/101 58036 10091 20067
 
WEATHER SUMMARY FOR MONDAY, APRIL 27, 2009
 
TEMPERATURE (DEGREES F)
MAX.....72    NORMAL......60
MIN.....49    NORMAL......41
MEAN....61    NORMAL......50
 
DEPARTURE FROM 30-YEAR NORMAL.................+11
TOTAL DEPARTURE FOR THE MONTH.................+72  [+2.5 DEGREE/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............. 4  DEPARTURE.......-11
TOTAL HEATING UNITS FOR THE MONTH............456  DEPARTURE.......-64
TOTAL HEATING UNITS FOR THE SEASON..........5874  DEPARTURE......-110
TOTAL HEATING UNITS LAST SEASON TO DATE.....5559  DIFFERENCE.....+315
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............29 S   AT 10:27 P.M.  
                   AEROVANE.............29 S   AT 10:27 P.M. 
                   ASOS.................28 S   AT 10:28 P.M.   
                   DAVIS................29 S   AT 10:27 P.M.     
FASTEST MILE FOR YESTERDAY..............22 S   AT 10:35 P.M.  
MAXIMUM 2-MINUTE ASOS AVERAGE...........21 S   AT 10:35 P.M.   
MAXIMUM 2-MINUTE DAVIS AVERAGE..........22 S   AT 10:34 P.M.   
                   AVERAGE..............N/A 
                   ASOS.................10.6
                   DAVIS.................9.8 E [100 deg]
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.... 0.00 DEPARTURE.........-0.13
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE MONTH...........4.53 DEPARTURE.........+0.60
                         ASOS...............4.55
TOTAL PRECIPITATION FOR THE YEAR...........14.61 DEPARTURE.........-2.95
                         ASOS..............15.68 #
# Includes erroneous ASOS precipitation data on 1/1/09, 1/2/09 and 2/27/09.
 
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.........-2.6
TOTAL SNOWFALL FOR THE SEASON..............78.9   DEPARTURE........+19.2
 
PRELIMINARY CLIMATE SUMMARY FOR APRIL 2009 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane recording wind system gust when significant
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
4/1  43/31/38/-3/0.13/0/015/02       24 SE    
4/2  52/39/46/+4/0.02/0/000/00       20 SSE       
4/3  58/45/52/+10/0.70//000/00       39 SSE   AERO 38 MPH SSE TSTM
4/4  51/38/45/+3/0.01/0/015/02       48 WSW   AERO 48 MPH WSW 
4/5  58/37/48/+5/0/0/551/71          40 W     AERO 37 MPH W
4/6  55/38/47/+4/1.42/0/047/006      42 SE    AERO 40 MPH SE  TSTM 
4/7  50/34/42/-1/T/0/109/14          36 WSW   AERO 35 MPH WSW
4/8  45/32/39/-5/0/0/149/19          33 SW    AERO 31 MPH SW
4/9  60/34/47/+3/0/0/692/88          36 SSW   AERO 33 MPH SSW
4/10 65/41/53/+9/0.18/0/544/69       37 SSW   AERO 35 MPH SSW 
4/11 44/33/39/-6/0.77/0.2/000/00     35 N     AERO 30 MPH N
4/12 43/29/36/-9/0/0/541/68          45 NW    AERO 43 MPH WNW
4/13 52/29/41/-4/0/0/734/92          38 W     AERO 35 MPH W
4/14 58/37/48/+2/0/0/696/87          25 E     
4/15 49/36/43/-3/0/0/650/81          35 NE    AERO 31 MPH NE
4/16 50/34/42/-4/0/0/806/100         29 NNE  
4/17 69/35/52/+5/0/0/695/86          37 W     AERO 33 MPH W
4/18 64/44/54/+7/0.05/0/170/21       28 W  
4/19 52/38/45/-2/0.03/0/773/95       33 NNE   AERO 28 MPH NNE
4/20 51/36/44/-4/0.10/0/.../...      43 E     AERO 39 MPH E
4/21 58/42/50/+2/0.95/0/000/00       43 E     AERO 43 MPH S
4/22 62/45/54/+5/0.16/0/.../..       28 S    
4/23 56/40/48/-1/0.01/0/.../..       43 W
4/24 70/40/55/+6/0/0/.../..          30 W
4/25 83/49/66/+16/T/0/.../..         29 S
4/26 88/56/72/+22/0/0/.../..         33 NE
4/27 72/49/61/+11/0/0/.../..         29 S
 
4/28 our morning low temp: 58F; our normal low is now 41F
 
NEW DAILY RECORDS FOR APRIL 2009...
New record high maximum temperature for April 25 of 83F
surpasses 80F in 1942.
New record high maximum temperature for April 26 of 88F
surpasses 83F in 1908
New record high minimum temperature for April 26 of 56F
surpasses 55F in 1985
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR APRIL 28
HIGH 92 IN 1990
LOW 26 IN 1947
PRECIP 2.41 IN 1904
SNOWFALL 10.0 IN. IN 1987
PEAK GUST 69 MPH NE 1967
 
RECORDS FOR APRIL 29
HIGH 85 IN 1974
LOW 26 IN 1909
PRECIP 1.65 IN 1923
SNOWFALL 1.0 IN. IN 1987
PEAK GUST 54 MPH WSW IN 1981
 
TODAY'S REPORT PREPARED BY: Robert Skilling