BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 22, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME
 
PARTLY CLOUDY WITH VERY DRY AIR AGAIN TODAY
 
It's been another very dry day here at the summit.  A trace of rainfall fell
overnight, but today has been another day of very low dew points and low
humidity values.  The relative humidity dropped under 30% late this morning
and has remained below that level.  We had a near normal morning low of 49F
this morning, and temperatures have risen a few degrees above normal this
afternoon, with a high of 73F so far.  It's been a partly cloudy day today,
with some mid-level cloudiness this morning replaced by developing
stratocumulus clouds this afternoon.  Winds have shifted from NW to W during
the day and have been breezy at times, with a peak gust so far of 28mph.
 
Today's Observations:
 
7 A.M.
Weather: Scattered altocumulus, cumulus distant ENE-S
Temperature: 54F; Dew Point: 44F; Wind: NW at 8 kts
Sea-level pressure: 29.83 ins. Hg, rising then falling
Visibility: 65 miles, light distant haze 
6-hr Max temp: 54F
6-hr Min temp: 49F
24-hr precip: Trace
BHO SA 1155 75 SCT 65 102/54/44/3108/983/ CU DSNT ENE-S LGT DSNT HZ/
8/150 50003 MANUAL 7000/ 10054 20049
 
10 A.M.
Weather: Clear, few distant cumulus
Temperature: 67F; Dew Point: 39F; Wind: WNW at 8 kts,
Wind: Direction variable W-NW
Sea-level pressure: 29.83 ins. Hg, falling then rising
Visibility: 65 miles, light distant haze
BHO SA 1455 CLR 65 103/67/39/3008/983/ FEW DSNT CU WND 26V32/ 8/100 53001
 
1 P.M.
Weather: Scattered stratocumulus
Temperature: 73F; Dew Point: 36F; Wind: W at 15G24 kts
Sea-level pressure: 29.80 ins. Hg, rising then falling
Visibility: 50 miles, distant haze
6-Hr Max temp: 73F
6-Hr Min temp: 54F
BHO SA 1755 75 SCT 50 092/73/36/2615G24/980/ DSNT HZ/
8/500 58011 10073 20054
 
SUMMARY FOR THURSDAY, MAY 21, 2015
  
TEMPERATURE (DEGREES F)
MAX.....66   NORMAL.....68
MIN.....43   NORMAL.....49
MEAN....55   NORMAL.....59
 
DEPARTURE FROM 30-YEAR NORMAL........................-4
TOTAL DEPARTURE FOR THE MONTH.......................+98 [+4.5 DEGREES/DAY]
 
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............10  DEPARTURE...........+2
TOTAL HEATING UNITS FOR THE MONTH.............113  DEPARTURE..........-95 
TOTAL HEATING UNITS FOR THE SEASON...........6384  DEPARTURE.........+142
TOTAL HEATING UNITS LAST SEASON TO DATE......6307  DIFFERENCE.........+77
 
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY..............0   DEPARTURE..........-1
TOTAL COOLING UNITS FOR THE MONTH.............16   DEPARTURE..........+6
TOTAL COOLING UNITS FOR THE SEASON............16   DEPARTURE..........+4
TOTAL COOLING UNITS LAST SEASON TO DATE.......13   DIFFERENCE.........+3
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY..................24   S   AT   6:32 P.M.        
                   ASOS.......................25   S   AT   5:38 P.M.           
                   DAVIS......................23   S   AT   4:05 P.M. RMY 24
FASTEST MILE FOR YESTERDAY....................18   S   AT   5:37 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE.................18   S   AT   6:42 P.M.           
MAXIMUM 2-MINUTE DAVIS AVERAGE................18   S   AT   5:39 P.M.    
AVERAGE WIND SPEED AND DIRECTION.............10.5  S      
                   ASOS......................11.2    
                   DAVIS......................9.5 SW [221 deg.]  
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....Trace  DEPARTURE.....-0.13
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE MONTH...........0.63  DEPARTURE.....-1.98 
                         ASOS...............0.63
TOTAL PRECIPITATION FOR THE YEAR...........18.55  DEPARTURE.....-2.48
                         ASOS................N/A ***
*** ASOS annual totals not available due to erroneous readings
 
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..............150.8  DEPARTURE....+88.1
 
PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY GUST
RMY:  R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
5/1  52/37/45/-8/0.00/0.0/354/42               21 NE  RMY 20
5/2  63/35/49/-4/0.00/0.0/668/79               20 S   RMY 20 
5/3  74/44/59/+6/0.00/0.0/509/60               22 S   RMY 22
5/4  83/47/65/+11/0.00/0.0/783/92              39 SSW RMY 45
5/5  77/56/67/+13/0.03/0.0/222/26              29 SW  RMY N/A
5/6  74/54/64/+10/0.00/0.0/574/67              24 SSW RMY 25
5/7  84/52/68/+13/0.00/0.0/824/96              29 S   RMY 32
5/8  74/44/59/+4/0.00/0.0/809/94               27 NNE RMY 26
5/9  77/44/61/+6/0.00/0.0/509/59               30 S   RMY 32
5/10 88/60/74/+19/0.00/0.0/692/80              28 SSW RMY 30
5/11 84/48/66/+10/0.00/0.0/529/61              30 NE  RMY 31
5/12 84/47/66/+10/0.24/0.0/287/33              33 WNW RMY 37 
5/13 67/47/57/+1/0.00/0.0/820/94               31 WNW RMY N/A
5/14 70/44/57/+0/0.00/0.0/.../..               22 NW  RMY 22
5/15 73/51/62/+5/0.00/0.0/.../..               20 WSW RMY 21
5/16 68/53/61/+4/T/0.0/.../..                  23 S   RMY 24
5/17 79/50/65/+8/T/0.0/.../..                  21 NE  RMY N/A
5/18 62/48/55/-3/..../0.0/.../..               25 NE  RMY N/A
5/19 63/50/57/-1/0.36/0.0/.../..               24 S   RMY 26
5/20 66/46/56/-2/0.00/0.0/.../..               32 WNW RMY 37 
5/21 66/43/55/-4/..../0.0/.../..               24 S   RMY 24
 
5/22 low since midnight is 49F; normal low is now 50F
 
DAILY RECORDS FOR MAY 2015
 
NONE SO FAR.
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated): 
 
RECORDS FOR MAY 22
HIGH 93F IN 1911
LOW 35F IN 1907
PRECIP 3.75 INCHES IN 1920
PEAK GUST 49e MPH SSW IN 1947
 
RECORDS FOR MAY 23
HIGH 92F IN 1964,1992
LOW 38F IN 1976
PRECIP 0.97 INS IN 1979
PEAK GUST 49e MPH W IN 1945
 
TODAY'S REPORT PREPARED BY: Jonathan O'Brien