BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, APRIL 27, 2009 
ALL TIMES ARE IN EASTERN STANDARD TIME 
 
LATE APRIL HEAT SETS THREE RECORDS IN TWO DAYS
TWO NEW HIGH TEMPERATURE RECORDS ESTABLISHED
YESTERDAY, APRIL 26, MAX 88F; MIN 56F
 
Yesterday was a second straight day with
record breaking late April heat. The high
temperature of 88F (88.3), which occurred
at 2:50 P.M., EDT easily surpassed our
previous record of 83F recorded in 1908.
A back door cold front dropped the temper-
ature sharply starting with a sudden wind-
shift from northwest to northeast at 5:40 P.M.
The drop was about 10 degrees in 20 minutes
and 14 degrees from 84F to 70F from 5 P.M.
to 6 P.M. EDT. Peak wind gusts reached 33
MPH NE by 6:33 P.M. EDT. 
The low temperature of 56F by midnight also
set a record for the highest minimum temp-
erature for April 26, surpassing 55F set in 1985. 
On Saturday, April 25, our maximum temperature
of 83F broke the record of 80F set in 1942. 
 
Today's weather observations: 
 
7 A.M.
Weather: Thin scattered cirrus
Temperature: 55F, Dew point: 39F, Wind: E at 4 kts
Sea-level pressure: 30.43 inches Hg, rising
Visibility: 50 miles, thin smoke along horizon W-N
6-hour minimum temperature: 49F
24-hour precipitation: 0.00
BHO SA 1155 300 –SCT 50 304/55/39/0904/043/ THN K LYR W-N/
8/001 53007 10055 20049
 
10 A.M. 
Weather: High thin scattered cirrus, altocumulus castellanus
southeast thru southwest 
Temperature: 64F, Dew point: 44F, Wind: NNE at 8 kts,
Wind: Direction variable NNW to ENE
Sea-level pressure: 30.41 inches Hg, falling
Visibility: 45 miles, light haze increasing
BHO SA 1455 300 –SCT 45 297/64/44/0308/041/ ACC SE-SW
LGT HZ INCRSNG WND 34V06/ 8/081 55007
 
1 P.M.  
Weather: High thin cirrus overcast with breaks  
Temperature: 66F, Dew point: 45F, Wind: NE at 8 kts,
Wind: Direction variable N-ENE
Sea-level pressure: 30.36 inches Hg, falling
Visibility: 35 miles, NE-E 20, WNW 45, haze increasing
6-hourly max. temp. 67F
BHO SA 1755 250 –SCT 300 –OVC 35 280/66/45/0408/036/ FEW AC S
BINOVC VSBY NE-E 20 WNW 45 HZ INCRSNG WND 35V06/ 8/081 58017
10067 20055
 
WEATHER SUMMARY FOR SUNDAY, APRIL 26, 2009
 
TEMPERATURE (DEGREES F)
MAX.....88    NORMAL......60
MIN.....56    NORMAL......40
MEAN....72    NORMAL......50
 
DEPARTURE FROM 30-YEAR NORMAL.................+22
TOTAL DEPARTURE FOR THE MONTH.................+61  [+2.1 DEGREE/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY............. 0  DEPARTURE.......-15
TOTAL HEATING UNITS FOR THE MONTH............452  DEPARTURE.......-53
TOTAL HEATING UNITS FOR THE SEASON..........5870  DEPARTURE.......-99
TOTAL HEATING UNITS LAST SEASON TO DATE.....5539  DIFFERENCE.....+331
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY............33 NE  AT  5:33 P.M. * 
                   AEROVANE.............31 NE  AT  5:27 P.M. *
                   ASOS.................33 NE  AT  5:27 P.M.  
                   DAVIS................33 W   AT 11:12 A.M.    
FASTEST MILE FOR YESTERDAY..............25 NE  AT  5:27 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...........24 NE  AT  5:27 A.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE..........24 WNW AT 11:51 A.M.  
                   AVERAGE..............14.1 W 
                   ASOS.................13.3
                   DAVIS................14.3 WNW [290 deg]
* last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.... 0.00 DEPARTURE.........-0.14
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE MONTH...........4.53 DEPARTURE.........+0.73
                         ASOS...............4.55
TOTAL PRECIPITATION FOR THE YEAR...........14.61 DEPARTURE.........-2.82
                         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.........-2.5
TOTAL SNOWFALL FOR THE SEASON..............78.9   DEPARTURE........+19.3
 
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     AERO 42 MPH 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 our morning low temp: 49F; our normal low is now 40F
 
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 27
HIGH 93 IN 1990
LOW 28 IN 1919
PRECIP 1.89 IN 1979
SNOWFALL 2.7 IN. IN 1993
PEAK GUST 65e MPH N IN 1941
 
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
 
TODAY'S REPORT PREPARED BY: Robert Skilling