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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 12, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME
 
LIGHT RAIN BEGINS AT MID-MORNING AND CONTINUES INTO
EARLY AFTERNOON...

After a beautiful spring day on Friday with a high 
temperature of 70F, clouds moved in overnight, and
the sky was overcast with altocumulus and altostratus
early this morning. Light rain showers began just
before 10 AM EST, and this became steady light rain
by 10:45 AM EST. As of 1 PM, lower clouds and fog
have moved in over the summit, and 0.07 inches of new
precipitation was measured. The temperature has 
struggled to climb much above the minimum this morning
of 48F, reaching a high of only 51F through early
afternoon. The wind has been generally light and
variable much of the day.   

Today's Observations:

7 A.M.
Weather: Scattered altocumulus, overcast altostratus, higher
clouds visible distant NNW-ESE, breaks in overcast distant N-NE
Temperature: 48F; Dew Point: 35F; Wind: E at 6 kts,
Wind: Light
Sea-level pressure: 30.21 ins. Hg, increasing, then steady    
Visibility: 70 miles
6-hr Max temp: 51F
6-hr Min temp: 48F
24-hr precip:  0.00 ins. 
BHO SA 1155 80 SCT E100 OVC 70 231/48/35/0806/021/ HIR CLDS 
VSBL DSNT NNW-ESE BINOVC DSNT N-NE WND LGT/ 8/071 51006 10051 20048

10 A.M.
Weather: Light rain shower, scattered stratocumulus, overcast 
nimbostratus 
Temperature: 50F; Dew Point: 43F; Wind: NE at 7 kts
Sea-level pressure: 30.21 ins. Hg, increasing, then decreasing  
Visibility: 25 miles
3-hr precip: Trace 
BHO SA 1455 35 SCT E50 OVC 25RW- 231/50/43/0307/021/ RW-B50 
VSBY NW-NE 10 SE-SW 35/ 8/52/ 50000 6000/

1 P.M.
Weather: Sky partly obscured, light rain and fog, few stratocumulus
SE-S, few stratus fractus below summit 
Temperature: 49F; Dew Point: 48F; Wind: NE at 3 kts (estimated)
Sea-level pressure: 30.16 ins. Hg, falling, then more quickly
Visibility: 2 miles, visibility N-NE 1/2, south 25
6-hr Max temp: 66F
6-hr Min temp: 60F
6-hr precip:  0.07 ins. 
BHO SA 1755 –X E3 OVC 2R-F 212/49/48/E0303/016/ F1 FEW SC 
SE-S FEW STFRA BLO SMT VSBY N-NE 10 S 25 WND LGT/ 8/52/ 
56019 6007/ 10051 20048
 
 
SUMMARY FOR FRIDAY, MAY 11, 2018

TEMPERATURE (DEGREES F)
MAX.....70   NORMAL.....65
MIN.....51   NORMAL.....46
MEAN....61   NORMAL.....56

DEPARTURE FROM 30-YEAR NORMAL..........................+5 
TOTAL DEPARTURE FOR THE MONTH........................+102 [+9.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............4   DEPARTURE..........-6
TOTAL HEATING UNITS FOR THE MONTH.............48   DEPARTURE.........-75
TOTAL HEATING UNITS FOR THE SEASON..........5741   DEPARTURE........-417
TOTAL HEATING UNITS LAST SEASON TO DATE.....5487   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.........+29
TOTAL COOLING UNITS FOR THE SEASON.............32   DEPARTURE.........+27
TOTAL COOLING UNITS LAST SEASON TO DATE........20   DEPARTURE.........+12

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................26 WNW AT 10:00 A.M.*
                   AERO........................24  NW AT 11:31 A.M. 
                   ASOS........................25 NNW AT  7:39 A.M.
                   DAVIS.......................26 M   AT  9:33 A.M.** RMY 28
FASTEST MILE FOR YESTERDAY.....................18  NW AT 11:38 A.M.*
MAXIMUM 2-MINUTE ASOS AVERAGE..................18  NW AT 11:41 A.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................19 M   AT  1:27 A.M.**
AVERAGE WIND SPEED AND DIRECTION.............11.0  NW
                   ASOS......................10.6 
                   DAVIS.....................10.4 M**
* Last of several occurrences
** 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..........0.42  DEPARTURE......-0.92
                         ASOS..............0.39  
TOTAL PRECIPITATION FOR THE YEAR..........25.73  DEPARTURE......+6.02
                         ASOS.............27.31

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/.../..    25 WNW AERO 21 WNW RMY 25
5/02 88/59/74/+21/0.00/0.0/.../..   37 WSW AERO 29 WSW RMY 35 
5/03 90/67/70/+26/..../0.0/.../..   36 SW  AERO 32 WSW RMY 36  
5/04 84/67/74/+20/..../0.0/.../..   39 SSW AERO 37 SSW RMY N/A
5/05 73/54/64/+10/0.00/0.0/.../..   56 W   AERO 55 W   RMY N/A
5/06 65/48/57/+3/0.21/0.0/.../..    24 NE  AERO 18 NE  RMY 21
5/07 62/49/56/+1/0.00/0.0/.../..    26 ENE AERO 22 NE  RMY 24
5/08 73/46/60/+5/0.00/0.0/.../..    25 SSE AERO 21 ESE RMY 23 
5/09 74/48/61/+6/..../0.0/.../..    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 Low temp since midnight is 48F; 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 12
HIGH 88F IN 2001
LOW 29F IN 1907
PRECIP 1.49 INCHES IN 1968
PEAK GUST 76 MPH S IN 1974

RECORDS FOR MAY 13
HIGH 85F IN 1947
LOW 35F IN 1914, 2005
PRECIP 2.39 INCHES IN 2006
PEAK GUST 49 MPH NNW IN 1965

TODAY'S REPORT PREPARED BY: Mike Iacono / Devin Richardt