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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, MAY 15, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME
 
DENSE FOG THIS MORNING QUICKLY CLEARED, LEADING
TO A RAPID INCREASE IN TEMPERATURE AND WIND THIS 
AFTERNOON.... 

Temperatures increased significantly between 7 A.M.
and 1:00 P.M; from 57F this morning to 83F this 
afternoon. This was due to a break in overcast skies after
8:00 A.M. The max so far today of 83F is 16 degrees
above the daily normal of 67F. A dense fog this morning
reduced visibility to a 1/2 mile, quickly clearing up
after 7:00 A.M. Wind picked up this afternoon, especially
following the 1:00 P.M. observation. 

The wind is currently at a speed over 20 mph, with a peak
gust of 50 mph (Time 1648EST). This is accompanied 
by heavy rain, lightning, and hail. 

Today's Observations:

7 A.M.
Weather: Overcast stratus, fog  
Temperature: 57F; Dew Point: 57F; Wind: S 9G16 kts
Sea-level pressure: 29.87 ins. Hg, falling then rising    
Visibility: 1/2 mile
6-hr Max temp: 56F
6-hr Min temp: 54F
24-hr precip: 0.00 ins.
BHO SA 1155 E5 OVC 1/2F 115/57/57/1909G16/987/ 8/6// 56001 
10056 20054 

10 A.M.
Weather: Broken altocumulus, broken cirrus, few cumulus
in all directions  
Temperature: 69F; Dew Point: 61F; Wind: SSW at 12G20 kts
Sea-level pressure: 29.86 ins. Hg, steady, then falling  
Visibility: 30 miles
3-hr precip: 0.00 ins. 
BHO SA 1455 E110 BKN 250 BKN 30 111/69/61/2012G20/986/ FEW CU 
ALQDS/ 8/122 58004 

1 P.M.
Weather: Scattered altocumulus, broken cirrus
Temperature: 83F; Dew Point: 60F; Wind: SSW at 12G20 kts 
Sea-level pressure: 29.79 ins. Hg, falling, then more quickly
Visibility: 30 miles
6-hr Max temp: 83F
6-hr Min temp: 57F
6-hr precip:  0.00 ins. 
BHO SA 1755 110 SCT E250 BKN 30 087/83/60/2012G20/979/ 8/022 58024 
10083 20057
 
SUMMARY FOR MONDAY, MAY 14, 2018

TEMPERATURE (DEGREES F)
MAX.....73   NORMAL.....66
MIN.....47   NORMAL.....48
MEAN....60   NORMAL.....57

DEPARTURE FROM 30-YEAR NORMAL..........................+3 
TOTAL DEPARTURE FOR THE MONTH........................+101 [+7.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............5   DEPARTURE..........-3
TOTAL HEATING UNITS FOR THE MONTH.............82   DEPARTURE.........-69
TOTAL HEATING UNITS FOR THE SEASON..........5775   DEPARTURE........-411
TOTAL HEATING UNITS LAST SEASON TO DATE.....5539   DIFFERENCE.......+236

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0   DEPARTURE...........0
TOTAL COOLING UNITS FOR THE MONTH..............32   DEPARTURE.........+27
TOTAL COOLING UNITS FOR THE SEASON.............32   DEPARTURE.........+25
TOTAL COOLING UNITS LAST SEASON TO DATE........20   DEPARTURE.........+12

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................23 S AT 6:36 P.M.
                   AERO........................18 S AT 6:36 P.M. 
                   ASOS........................22 S AT 6:35 P.M.
                   DAVIS.......................21 M AT 6:27 P.M.** RMY 16
FASTEST MILE FOR YESTERDAY.....................15 S AT 6:28 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................17 S AT 6:36 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................17 M AT 6:35 P.M.**
AVERAGE WIND SPEED AND DIRECTION..............9.4 S
                   ASOS.......................9.5 
                   DAVIS......................8.8 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......-1.10
                         ASOS..............0.57  
TOTAL PRECIPITATION FOR THE YEAR..........25.92  DEPARTURE......+5.84
                         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 73/47/60/+3/0.00/0.0/.../..    23 S   AERO 18 S   RMY 21

5/15 Low temp since midnight is 54F; normal low is now 48F

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 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: Benjamin Turner