BLUE HILL METEOROLOGICAL OBSERVATORY 
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 19, 2012
ALL TIMES ARE IN EASTERN STANDARD TIME
 
WARM AND SUNNY WITH ONLY A FEW CLOUDS TODAY...

The sky has been nearly totally free of clouds today with
only a band of thin cirrus visible to the southeast all day
as a storm passes far offshore.  The low temperature of 51 
and the high so far of 72 will provide for another warmer
than average day, and much of the next week looks to be
near or above average for temperature. Other than a little
distant haze, the visibility has been very good today in the
70-75 mile range due to a low relative humidity below
35% this afternoon.  

The thunderstorm on the 16th was the first of the year.
This is relatively late, though it was not the latest
first thunderstorm in any year. Looking back to 1950, 
this occurred on June 21st in 1971.  

Latest First Thunderstorm, (1950-2012):

1) 21 June 1971
2) 19 June 1978
3)  3 June 1960
4) 20  May 1968
5) 19  May 1964
6) 16  May 2012


Today's observations:
 
7 A.M.
Weather: Clear, few cirrus distant E-S, light distant haze,
thin smoke layer along horizon NNW-NNE (over city)
Temperature: 58F, Dew Point: 42F; Wind: N at 5 kts,
Wind: Light and variable
Sea-level pressure: 30.19 inches Hg, rising 
Visibility: 75 miles, light distant haze
6-hour min. temp: 51F
BHO SA 1155 CLR 75 222/58/42/3505/019/ FEW CI DSNT E-S LGT DSNT HZ 
THN K LYR ALG HRZN NNW-NNE WND LGT AND VRB/ 8/001 53010 10058 20051

10 A.M.
Weather: Clear, few cirrus distant E-SSW, light distant haze,
thin smoke layer NW-NNW
Temperature: 67F, Dew Point: 40F; Wind: ENE at 6 kts,
Wind: Light and variable
Sea-level pressure: 30.18 inches Hg, falling slightly 
Visibility: 75 miles, light distant haze
BHO SA 1455 CLR 75 219/67/40/0606/018/ FEW CI DSNT E-SSW LGT DSNT HZ 
THN K LYR NW-NNW WND LGT AND VRB/ 8/001 58003
 
1 P.M.
Weather: Thin scattered cirrus, cirrus band E-SSW, light 
distant haze
Temperature: 72F, Dew Point: 42F; Wind: NE at 7 kts,
Wind: Direction variable N-E
Sea-level pressure: 30.17 inches Hg, falling slowly 
Visibility: 70 miles, light distant haze
BHO SA 1755 220 亡CT 70 218/72/42/0507/017/ CI BND E-SSW LGT DSNT HZ 
WND 01V09/ 8/001 58001 10072 20058

 
WEATHER SUMMARY FOR FRIDAY, MAY 18

TEMPERATURE (DEGREES F)
MAX.....69    NORMAL.....67
MIN.....49    NORMAL.....48
MEAN....59    NORMAL.....58
 
DEPARTURE FROM 30-YEAR NORMAL........................+1
TOTAL DEPARTURE FOR THE MONTH.......................+21 [+1.0 DEGREE/DAY]

HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY...............6   DEPARTURE..........-2
TOTAL HEATING UNITS FOR THE MONTH.............159   DEPARTURE.........-31
TOTAL HEATING UNITS FOR THE SEASON...........4873   DEPARTURE.......-1343
TOTAL HEATING UNITS LAST SEASON TO DATE......6103   DIFFERENCE......-1230

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............17 ESE AT  6:21 P.M.   
                   AERO..................17 ESE AT  4:38 P.M.  
                   ASOS..................17 S   AT 10:03 P.M.  
                   DAVIS.................17 ESE AT  6:22 P.M. RMY 17
THE FASTEST MILE FOR YESTERDAY...........13 SSW AT 10:05 P.M.    
MAXIMUM 2-MINUTE ASOS AVERAGE............13 SSW AT 10:42 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE...........13 SE  AT  6:57 P.M.  
AVERAGE WIND SPEED AND DIRECTION....... 8.4 SSW  
                   ASOS.................7.2  
                   DAVIS................7.1 SSE [160 deg.]
* last of several occurrences...

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..........2.95   DEPARTURE..........+0.74
                         ASOS..............2.87
TOTAL PRECIPITATION FOR THE YEAR..........12.56   DEPARTURE..........-8.20
                         ASOS.............12.60
	
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0    DEPARTURE...........0.0
TOTAL SNOWFALL FOR THE MONTH................0.0    DEPARTURE..........-0.1
TOTAL SNOWFALL FOR THE SEASON..............24.2    DEPARTURE.........-35.9

PRELIMINARY CLIMATE SUMMARY FOR MAY 2012 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust when significant
RMY:  RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized

5/1  47/42/45/-8/0.65/0.0/000/00    33 SE  AERO 36 MPH SE  RMY 37 
5/2  50/43/47/-6/0.05/0.0/000/00    16 ENE AERO 16 MPH ENE RMY 17
5/3  51/44/48/-5/0.08/0.0/000/00    14 SSE AERO 16 MPH SSE RMY N/A
5/4  56/47/52/-2/0.01/0.0/000/00    21 SSW AERO 25 MPH SSW RMY 23
5/5  57/46/52/-2/0.04/0.0/034/04    14 NE  AERO 15 MPH NE  RMY 15 
5/6  58/45/52/-2/0.00/0.0/532/62    21 ENE AERO 21 MPH ENE RMY 21
5/7  67/48/58/+3/0.00/0.0/740/86    23 S   AERO 25 MPH S   RMY 25
5/8  57/48/53/-2/0.18/0.0/000/00    40 S   AERO 46 MPH S   RMY 46 
5/9  61/54/58/+3/0.36/0.0/000/00    25 S   AERO 28 MPH S   RMY N/A
5/10 65/46/56/+1/0.98/0.0/234/27    33 W   AERO 36 MPH W   RMY 37
5/11 62/42/52/-4/T/0.0/539/62       30 WNW AERO 33 MPH WNW RMY 34
5/12 77/46/62/+6/0.00/0.0/862/99    30 W   AERO 30 MPH W   RMY 29
5/13 82/57/70/+14/0.00/0.0/314/36   27 S   AERO 29 MPH S   RMY 29
5/14 71/52/62/+5/0.05/0.0/096/11    23 S   AERO 24 MPH S   RMY 23
5/15 72/57/65/+8/0.43/0.0/123/14    32 S   AERO 35 MPH S   RMY 33 
5/16 71/58/65/+8/0.12/0.0/141/16    23 S   AERO 24 MPH S   RMY N/A 
5/17 69/50/60/+3/0.00/0.0/.../..    31 WNW AERO 32 MPH WNW RMY 26
5/18 69/49/59/+1/0.00/0.0/.../..    17 ESE AERO 17 MPH ESE RMY 17

5/19 morning low temp: 51F; the normal low is now 49F


DAILY RECORDS FOR MAY 2012
5/16 - Minimum temperature of 56F equals record high minimum 
      for the date set in 1951 and 1961 

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):

RECORDS FOR MAY 19
HIGH 91F IN 1962
LOW 34F IN 2002
PRECIP 1.54 INCHES IN 1900
PEAK GUST 58 MPH NW IN 1964

RECORDS FOR MAY 20
HIGH 91F IN 1975,1996
LOW 37F IN 1948, 2002
PRECIP 1.65 INCHES IN 1969
PEAK GUST 57 MPH S IN 1963, WNW IN 1982

TODAY'S REPORT PREPARED BY: Mike Iacono/Peter Volpe