BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, MAY 14, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME
 
ANOTHER DAY BEGINS FOGGY AND OVERCAST WITH CLOUDS
DECREASING FOR A PARTLY SUNNY AFTERNOON...

Temperatures this weekend were below seasonable with
a max yesterday of 58F, which is 7 degrees below the
daily normal of 65F. Today so far we have reached a more
seasonable max of 67F by 1:00 P.M., one degree above the
daily normal of 66F.  
Both today and yesterday morning started with very light
precipitation and fog. The fog limited visibility today 
to 15 miles at 7:00 A.M. but increased to 70 miles by
10:00 A.M. as humidity decreased. Only a trace of rainfall 
was measured since yesterday morning at 7:00 A.M. On 
Saturday we received 0.19 ins of rainfall. Clouds began to 
decrease just before the 10:00 A.M. observation today and 
have continued to decrease throughout the day with only a 
quarter of the sky covered with clouds by 1:00 P.M. Wind 
continues to be light and from the SW.    

Today's Observations:

7 A.M.
Weather: Very light rain ending at 6:59 A.M EST,
Overcast nimbostratus  
Temperature: 50F; Dew Point: 48F; Wind: S at 6 kts,
Wind: Light
Sea-level pressure: 30.03 ins. Hg, increasing, then steady    
Visibility: 15 miles, except 30 miles NE-E, distant fog in
all directions
6-hr Max temp: 50F
6-hr Min temp: 46F
24-hr precip:  Trace
BHO SA 1155 E10 OVC 15L- 170/50/48/1706/003/ PCPN VRY L-59 
VSBY 30 NE-E DSNT FG ALQDS WND LGT/ 8/6// 50005 10050 20046 

10 A.M.
Weather: Broken stratus  
Temperature: 59F; Dew Point: 49F; Wind: SW at 6 kts,
Wind: Light
Sea-level pressure: 30.00 ins. Hg, falling, then more slowly  
Visibility: 70 miles, distant fog in all directions
3-hr precip: 0.00 ins. 
BHO SA 1455 E20 BKN 70 160/59/49/2206/000/ DSNT FG ALQDS WND LGT/ 
8/6// 58010

1 P.M.
Weather: Scattered cumulus, scattered cirrostratus
Temperature: 67F; Dew Point: 51F; Wind: S at 7 kts 
Sea-level pressure: 29,96 ins. Hg, falling, then more quickly
Visibility: 70 miles
6-hr Max temp: 67F
6-hr Min temp: 50F
6-hr precip:  0.00 ins. 
BHO SA 1755 29 SCT 200 SCT 70 145/67/51/1807/996/ 8/105 58015 
10067 20050
 
SUMMARY FOR SUNDAY, MAY 13, 2018

TEMPERATURE (DEGREES F)
MAX.....58   NORMAL.....66
MIN.....46   NORMAL.....47
MEAN....52   NORMAL.....56

DEPARTURE FROM 30-YEAR NORMAL..........................-4 
TOTAL DEPARTURE FOR THE MONTH.........................+98 [+7.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............13   DEPARTURE..........+4
TOTAL HEATING UNITS FOR THE MONTH.............77   DEPARTURE.........-65
TOTAL HEATING UNITS FOR THE SEASON..........5770   DEPARTURE........-407
TOTAL HEATING UNITS LAST SEASON TO DATE.....5519   DIFFERENCE.......+251

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0   DEPARTURE...........0
TOTAL COOLING UNITS FOR THE MONTH..............32   DEPARTURE.........+28
TOTAL COOLING UNITS FOR THE SEASON.............32   DEPARTURE.........+26
TOTAL COOLING UNITS LAST SEASON TO DATE........20   DEPARTURE.........+12

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................20 S AT 10:16 P.M.
                   AERO........................17 S AT 10:16 P.M. 
                   ASOS........................18 S AT 10:16 P.M.
                   DAVIS.......................17 M AT 10:16 P.M.** RMY 16
FASTEST MILE FOR YESTERDAY.....................13 S AT 10:16 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................13 S AT 11:03 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................13 M AT 10:17 P.M.**
AVERAGE WIND SPEED AND DIRECTION..............5.8 NE
                   ASOS.......................6.5 
                   DAVIS......................5.8 M**
** Davis direction malfunctioning 

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..........0.61  DEPARTURE......-0.98
                         ASOS..............0.57  
TOTAL PRECIPITATION FOR THE YEAR..........25.92  DEPARTURE......+5.96
                         ASOS.............27.49

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..............92.8  DEPARTURE.......+30.0

PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system 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
M:    Missing data

5/01 65/39/52/-1/0.00/0.0/625/74    25 WNW AERO 21 WNW RMY 25
5/02 88/59/74/+21/0.00/0.0/584/69   37 WSW AERO 29 WSW RMY 35 
5/03 90/67/70/+26/..../0.0/433/51   36 SW  AERO 32 WSW RMY 36  
5/04 84/67/74/+20/..../0.0/102/12   39 SSW AERO 37 SSW RMY N/A
5/05 73/54/64/+10/0.00/0.0/615/72   56 W   AERO 55 W   RMY N/A
5/06 65/48/57/+3/0.21/0.0/000/00    24 NE  AERO 18 NE  RMY 21
5/07 62/49/56/+1/0.00/0.0/713/83    26 ENE AERO 22 NE  RMY 24
5/08 73/46/60/+5/0.00/0.0/852/99    25 SSE AERO 21 ESE RMY 23 
5/09 74/48/61/+6/..../0.0/768/89    23 ESE AERO 18 ESE RMY 21 
5/10 73/48/61/+6/..../0.0/.../..    33 S   AERO 30 S   RMY 32 
5/11 70/51/61/+5/..../0.0/.../..    26 WNW AERO 24 NW  RMY 28
5/12 51/47/49/-7/0.19/0.0/.../..    25 E   AERO 23 E   RMY N/A
5/13 58/46/52/-4/T/0.0/.../..       20 S   AERO 17 S   RMY 16 

5/14 Low temp since midnight is 47F; normal low is now 47F

DAILY RECORDS FOR MAY 2018

5/03/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 67F,
         BREAKS PREVIOUS RECORD OF 66F SET IN 2001

5/04/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 67F,
         BREAKS PREVIOUS RECORD OF 66F SET IN 2001

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

RECORDS FOR MAY 14
HIGH 85F IN 1961
LOW 33F IN 1895
PRECIP 1.93 INCHES IN 2006
PEAK GUST 53 MPH S IN 2009

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

TODAY'S REPORT PREPARED BY: Kaitlin Geagan