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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 23, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

FAIR WEATHER AND GOOD VISIBILITY PREVAIL FOLLOWING
A MOSTLY CLOUDY MORNING....

We observed a visibility of 30 miles and mostly cloudy 
skies this morning. Clouds decreased after noontime, with
the sky becoming almost clear by 1 P.M. Visibility increased
to 70 miles by 10 A.M. due to drier air entering the region.
The humidity of 92% this morning decreased to 42% by the 1 P.M.
observation. We reached a maximum temperature so far of 77F, 9 
degrees above the daily normal of 68F.  

Today's Observations:

7 A.M.
Weather: Scattered cirrostratus, few altocumulus in
all directions
Temperature: 58F; Dew Point: 56F; Wind: W at 6G14 kts,
Wind: Light
Sea-level pressure: 29.91 ins. Hg, rising, then more rapidly    
Visibility: 30 miles 
6-hr Max temp: 58F
6-hr Min temp: 56F
24-HR Precip: 0.04
BHO SA 1155 250 SCT 30 128/58/56/2806G14/991/ FEW AC ALQDS 
WND LGT/ 8/085 53003 MANUAL 70004 ASOS 70003 10058 20051  

10 A.M.
Weather: Scattered cumulus
Temperature: 70F; Dew Point: 55F; Wind: NNW at 9 kts 
Sea-level pressure: 29.92 ins. Hg, rising, then more rapidly
Visibility: 70 miles
3-hr Precip: 0.00 in
BHO SA 1455 32 SCT 70 131/70/55/3409G14/992/ 8/100 53003 

1 P.M.
Weather: Few cumulus SE-N, few cirrostratus SE-NW
Temperature: 77F; Dew Point: 52F; Wind: NNW at 8G16 kts 
Sea-level pressure: 29.91 ins. Hg, rising then falling
Visibility: 70 miles
6-hr Max temp: 77F
6-hr Min temp: 58F
6-hr precip:  0.00 ins.
BHO SA 1755 CLR 70 127/77/52/3408G16/991/ FEW CU SE-N FEW 
CS SE-SW/ 8/105 58004 10077 20058    

SUMMARY FOR TUESDAY, MAY 22, 2018

TEMPERATURE (DEGREES F)
MAX.....68   NORMAL.....68
MIN.....51   NORMAL.....50
MEAN....60   NORMAL.....59

DEPARTURE FROM 30-YEAR NORMAL.........................+1
TOTAL DEPARTURE FOR THE MONTH.......................+109 [+4.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............5   DEPARTURE..........-1
TOTAL HEATING UNITS FOR THE MONTH............129   DEPARTURE.........-86
TOTAL HEATING UNITS FOR THE SEASON..........5822   DEPARTURE........-428
TOTAL HEATING UNITS LAST SEASON TO DATE.....5583   DIFFERENCE.......+239

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0   DEPARTURE...........0
TOTAL COOLING UNITS FOR THE MONTH..............37   DEPARTURE.........+26
TOTAL COOLING UNITS FOR THE SEASON.............37   DEPARTURE.........+24
TOTAL COOLING UNITS LAST SEASON TO DATE........56   DEPARTURE.........-19

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................23 S  AT  2:55 P.M.
                   AERO........................21 S  AT  4:37 P.M. 
                   ASOS........................23 S  AT  5:36 P.M.
                   DAVIS.......................23 M  AT  3:25 P.M.** RMY 22
FASTEST MILE FOR YESTERDAY.....................16 S  AT 10:38 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................17 S  AT 10:38 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................18 M  AT 10:38 P.M.**
AVERAGE WIND SPEED AND DIRECTION..............8.8 S
                   ASOS.......................9.5
                   DAVIS......................8.7 M**
** Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.04  DEPARTURE......-0.10
                         ASOS..............0.03
TOTAL PRECIPITATION FOR THE MONTH..........1.82  DEPARTURE......-0.93
                         ASOS..............1.80  
TOTAL PRECIPITATION FOR THE YEAR..........27.13  DEPARTURE......+6.01
                         ASOS.............28.72

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 90/67/79/+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 83/54/69/+12/..../0.0/.../..   51 NW  AERO 50 NW  RMY 54 TSTM
5/16 56/49/53/-4/T/0.0/.../..       32 ENE AERO 28 ENE RMY 30
5/17 72/51/62/+5/0.02/0.0/.../..    17 SW  AERO 14 SW  RMY N/A
5/18 62/43/53/-5/0.00/0.0/.../..    35 ENE AERO 33 ENE RMY N/A
5/19 57/43/50/-8/.../0.0/.../..     22 E   AERO 17 E   RMY N/A
5/20 77/54/66/+8/.../0.0/.../..     33 SW  AERO 31 SW  RMY 33 TSTM
5/21 77/52/65/+6/0.00/0.0/.../..    22 W   AERO 18 W   RMY 20
5/22 68/51/60/+1/0.04/0.0/.../..    23 SSW AERO 21 S   RMY 22

5/23 Low temp since midnight is 51F; normal low is now 50F

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 23
HIGH 92F IN 1964,1992
LOW 38F IN 1976
PRECIP 0.97 INS IN 1979
PEAK GUST 49e MPH W IN 1945

RECORDS FOR MAY 24
HIGH 92F IN 1964
LOW 35F IN 1956
PRECIP 2.13 INS IN 1951
PEAK GUST 54 MPH NNE IN 2005

TODAY'S REPORT PREPARED BY: Benjamin Turner