BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, MAY 5, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME
 
COOL, DRY CONDITIONS CONTINUE
 
The low temperature fell to 37F at the summit this morning, our coldest
reading of the month so far and well below the average morning low for
this time of year of 45F.  With winds coming in off the ocean again today,
temperatures have been held below 60F, topping out at 57F so far by 1PM
this afternoon, which is below our average for this date of 63F.  We are
on track for our third straight day of below average temperatures. 
The day began with broken stratocumulus clouds covering a large portion
of the sky, but these gradually decreased in coverage through late morning
and early afternoon, allowing for plenty of sunshine with cirrus clouds
moving in.  Visibility has been held to 40 miles or less today as we
have once again had to deal with quite a bit of haze. 
 
Very dry weather continues.  From March 20 through today (47 days),
Blue Hill has received only 2.44 inches of precipitation. That is only
33% of the 30-year normal of 7.42 inches for this time period.  No
measurable precipitation has fallen since April 25.
 
APRIL 2013 PRELIMINARY STATISTICS:
(departures relative to 1981-2010 average)
 
TEMPERATURE:
Average Max Temp:  58.1F [+2.4F]
Average Min Temp:  38.1F [+0.4F]
Mean Temp:  48.1F [+1.4F]
24-hr. Corr. Mean Temp:  47.0F [+0.7F]
Max Temp:  72F on 9th, 19th, 24th
Min Temp:  26F on 4th
Total heating degree day units (month):    502 [ -49] *NCDC method
Total heating degree day units (season): 5,522 [-513] *start July 1 (NCDC)
 
PRECIPITATION:
Total precipitation:  2.29 inches [-2.26 inches]
Greatest 24-hr precipitation:  0.61 inches on 11th/12th
Total snowfall:  Trace [-3.0 inches]
Total seasonal snowfall:  99.0 inches [+36.3 inches]
 
WIND:
Avg wind speed:  13.3 MPH
Avg corrected wind speed:  13.7 MPH
Prevailing wind direction: S [14%]
Peak gust: 51 MPH S on 7th
Peak fastest mile: 40 MPH S on 7th
 
SUNSHINE:
Astronomical minutes: 14,392 of possible 24,094 or 60%
Campbell-Stokes card minutes: 13,872* of possible 23,250 or 60% *Corrected
total
 
Today's observations:
 
7 A.M.
Weather: Broken stratocumulus
Temperature: 45F; Dew Point: 40F; Wind: N at 6 kts
Sea-level pressure: 30.34 ins. Hg, rising
Visibility: 30 miles, hazy
6-hour min. temp: 37F
BHO SA 1155 E10 BKN 30 275/45/40/0106/034/ HAZY/ 8/500 52010 10045 20037
 
10 A.M.
Weather: Broken stratocumulus, few lower cumulus fractus, few altocumulus
E-SE, few cirrus NW-NE
Temperature: 51F; Dew Point: 40F; Wind: ENE at 8 kts,
Wind: Direction variable N-E
Sea-level pressure: 30.34 ins. Hg, rising then falling
Visibility: 35 miles, distant haze
BHO SA 1455 E15 BKN E120 BKN E250 BKN 35 274/51/40/0608/034/
FEW LWR CUFRA FEW AC E-SE FEW CI NW-NE DSNT HZ WND 35V10/ 8/571 58001
 
1 P.M.
Weather: Clear, few stratocumulus ENE-SSE, cirrus SW-NNE
Temperature: 57F; Dew Point: 40F; Wind: ENE at 8 kts,
Wind: Direction variable NNE-ESE
Sea-level pressure: 30.32 ins. Hg, falling
Visibility: 40 miles, distant haze
6-hour max. temp: 57F
BHO SA 1755 CLR 40 268/57/40/0708/032/ FEW SC ENE-SSE CI SW-NNE DSNT HZ
WND 30V11 8/501 57006 10057 20045
 
WEATHER SUMMARY FOR SATURDAY, MAY 4, 2013
 
TEMPERATURE (DEGREES F)
MAX.....55     NORMAL.....63
MIN.....40     NORMAL.....44
MEAN....48     NORMAL.....54
 
DEPARTURE FROM 30-YEAR NORMAL....................-6
TOTAL DEPARTURE FOR THE MONTH....................-2 [-0.3 DEGREES/DAY]
 
HEATING DEGREE DAYS 
TOTAL HEATING UNITS FOR YESTERDAY............17   DEPARTURE..........+5
TOTAL HEATING UNITS FOR THE MONTH............32   DEPARTURE..........+1
TOTAL HEATING UNITS FOR THE SEASON.........5571   DEPARTURE........-512
TOTAL HEATING UNITS LAST SEASON TO DATE....4782   DIFFERENCE.......+789
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY...............21 NE  AT   9:36 A.M.
                   AERO....................23 NE  AT   9:36 A.M.
                   ASOS....................23 NE  AT   1:28 P.M.
                   DAVIS...................22 ENE AT   1:21 P.M. RMY: 23
THE FASTEST MILE FOR YESTERDAY.............18 NE  AT   1:19 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE..............17 E   AT  12:39 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE.............15 ENE AT   1:22 P.M.
AVERAGE WIND SPEED AND DIRECTION..........9.8 ENE
                   ASOS...................9.1
                   DAVIS..................8.8 ENE [060 deg]
* Last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE...........-0.12
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH.........Trace  DEPARTURE...........-0.49
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE YEAR..........16.38  DEPARTURE...........-2.66
                         ASOS..............N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals
                       
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.............0.0
TOTAL SNOWFALL FOR THE SEASON.............99.0   DEPARTURE...........+36.3
 
PRELIMINARY CLIMATE SUMMARY FOR APRIL AND MAY 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
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  67/45/56/+3/0.00/.../..         18 E   AERO 16 MPH E   RMY 17
5/2  75/43/59/+6/T/.../..            29 NE  AERO 26 MPH NE  RMY 29
5/3  54/42/48/-5/0.00/.../..         24 NE  AERO 25 MPH NE  RMY 28
5/4  55/40/48/-6/0.00/.../..         21 NE  AERO 23 MPH NE  RMY 23  
 
5/5 morning low temp: 37F; the normal low is now 45F
 
DAILY RECORDS FOR MAY 2013
None so far.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR MAY 5
HIGH 92F IN 1949
LOW 30F IN 1891
PRECIP 2.74 INCHES IN 1922
SNOWFALL 3.0 INCHES IN 1917
PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976
 
RECORDS FOR MAY 6
HIGH 90F IN 1930
LOW 29F IN 1891
PRECIP 1.04 INCHES IN 1890
SNOWFALL TRACE IN 1917,1996
PEAK GUST 65 MPH SSE IN 1989
 
TODAY'S REPORT PREPARED BY: Jonathan O'Brien