BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 15, 2013 
ALL TIMES ARE IN EASTERN STANDARD TIME
 
MILDER TEMPERATURES ARRIVE IN STILL DRY AIR MASS
CLOUDS ON THE INCREASE AHEAD OF APPROACHING WARM FRONT
WINDS BECOMING GUSTY OUT OF THE SOUTH-SOUTH-SOUTHWEST
 
Milder air from the south and southwest has brought
temperatures into the 60's today after a chill maximum
of 58F yesterday.  Middle and high clouds have been on
the increase ahead of an approaching warm front.  The
air continues dry early this afternoon with dew points
still in the low 30's.
Visibility has steadily decreased in haze today going
from 60 miles early down to 30 miles by early afternoon. 
South winds were increasing with gusts to 20 to 30 mph.
 
Today's observations:
 
7 A.M.
Weather: Clear, few altocumulus and altocumulus lenticularis
to the distant WSW-W, few cirrus SW-WNW 
Temperature: 51F; Dew Point: 28F; Wind: SW at 6 kts,
Wind: Direction gradually backing
Sea-level pressure: 30.06 ins. Hg, rising then more slowly
Visibility: 60 miles, distant haze
6-hour min. temp: 41F
24-hour precip: trace
BHO SA 1155 CLR 60 178/51/28/2306/006/ FEW AC/ACSL DSNT WSW-W FEW
CI SW-WNW DSNT HZ WND GRDLY BACKING/ 8/041 51002 10051 20041  
 
10 A.M.
Weather: Scattered dense cirrus, thin scattered cirrus,
cumulus forming distant SE-SSE and SW 
Temperature: 62F; Dew Point: 33F; Wind: SSW at 11 kts,
Wind: Direction variable S-WSW
Sea-level pressure: 30.01 ins. Hg, falling then more rapidly
Visibility: 55 miles, distant haze increasing 
BHO SA 1455 220 SCT 300 –SCT 55 162/62/33/2111/001/
FEW CU FRMG DSNT SE-SSE AND SW AC/ACSL DSNT SSW-WNW
PTCHS DNS CI SSW-WNW FEW CCSL SE-S THN CI E-SE DSNT HZ INCR
WND 18V24/ 8/142/ 58016
 
1 P.M.
Weather: Broken altocumulus/altocumulus lenticularis, altocumulus
of a chaotic sky, broken cirrus overcast cirrostratus (thin)
Temperature: 64F; Dew Point: 33F; Wind: W at 15G21 kts,
Wind: Direction variable SE-SSW
Sea-level pressure: 29.93 ins. Hg, falling then more rapidly
Visibility: 30 miles, hazy, haze increasing 
6-hour max temp: 65F
BHO SA 1755 E75 BKN 220 BKN 300 OVC 30 136/64/33/1715G21/993/
ACSL ALQDS AC CHAOTIC SKY HIER CS LYR THN HAZY HZ INCR
WND 14V20/ 8/098 58026 10065 20051  
 
WEATHER SUMMARY FOR TUESDAY, MAY 14, 2013
 
TEMPERATURE (DEGREES F)
MAX.....58     NORMAL.....66
MIN.....38     NORMAL.....47
MEAN....48     NORMAL.....57
 
DEPARTURE FROM 30-YEAR NORMAL....................-9
TOTAL DEPARTURE FOR THE MONTH...................+21 [+1.3 DEGREE/DAY]
 
HEATING DEGREE DAYS 
TOTAL HEATING UNITS FOR YESTERDAY............17   DEPARTURE..........+8
TOTAL HEATING UNITS FOR THE MONTH...........124   DEPARTURE.........-27
TOTAL HEATING UNITS FOR THE SEASON.........5646   DEPARTURE........-540
TOTAL HEATING UNITS LAST SEASON TO DATE....4862   DIFFERENCE.......+784
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY...............22 W   AT 12:37 P.M.
                   AERO....................24 W   A8 12:37 P.M.
                   ASOS....................24 NW  AT  4:08 P.M.
                   DAVIS...................22 W   AT 11:27 A.M. RMY: 25
FASTEST MILE FOR YESTERDAY.................16 W   AT 12:37 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..............17 NW  AT  4:11 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE.............17 NW  AT  4:11 P.M.
AVERAGE WIND SPEED AND DIRECTION.........10.3 WNW
                   ASOS...................9.0
                   DAVIS..................8.8 NW [310 deg]
*Last of several occurrences...
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...trace  DEPARTURE...........-0.12
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........0.94  DEPARTURE...........-0.77
                         ASOS..............0.89
TOTAL PRECIPITATION FOR THE YEAR..........17.32  DEPARTURE...........-2.94
                         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 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/+3/0.00/845/100        18 E   AERO 16 MPH E   RMY 17
5/2  75/43/59/+6/T/669/79            29 NE  AERO 26 MPH NE  RMY 29
5/3  54/42/48/-5/0.00/706/83         24 NE  AERO 25 MPH NE  RMY 28
5/4  55/40/48/-6/0.00/843/99         21 NE  AERO 23 MPH NE  RMY 23  
5/5  58/37/48/-6/0.00/752/88         17 ENE AERO 17 MPH ENE RMY 20
5/6  66/40/53/-1/0.00/600/70         17 S   AERO 18 MPH S   RMY 20
5/7  77/50/64/+9/0.00/807/94         21 S   AERO 23 MPH S   RMY 25
5/8  71/55/63/+8/0.42/112/13         31 SSE AERO 35 MPH SSE RMY 35 TSTM
5/9  66/56/61/+6/0.41/078/09         16 NE  AERO 16 MPH NE  RMY 18 TSTM
5/10 79/54/66/+11/T/333/63           18 S   AERO 21 MPH S   RMY N/A
5/11 70/56/63/+7/0.06/.../..         43 SSW AERO 44 MPH SSW RMY 46
5/12 71/47/59/+3/0.05/339/39         30 W   AERO 32 MPH W   RMY 32
5/13 60/41/51/-5/0.00/.../..         25 WSW AERO 28 MPH WSW RMY 30
5/14 58/38/48/-9/T/.../..            22 W   AERO 24 MPH W   RMY 25 
 
5/15 morning low temp: 41F; the normal low is now 48F
 
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 15
HIGH 93F IN 1900
LOW 36F IN 1947,1985
PRECIP 1.63 INCHES IN 1978
PEAK GUST 53e MPH NE IN 1978, W 2002
 
RECORDS FOR MAY 16
HIGH 90F IN 1951
LOW 30F IN 1936
PRECIP 2.63 INCHES IN 1954
PEAK GUST 56e MPH NW IN 1952
 
TODAY'S REPORT PREPARED BY: Robert Skilling