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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, JULY 19, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

HIGH PRESSURE BRINGS CLEAR DRY DAY WITH LIGHT WIND... 

High pressure moved into the area bringing clear dry 
weather to Great Blue Hill today. Day time temperatures 
continue to be close to seasonable with a high so far of 
79F, which is 2 degrees below the daily normal of 81F. 
Overnight temperatures were below normal with a low of 56F, 
this is 7 degrees below the daily normal of 63F. The air 
was very dry today with dew points dropping to the upper 
40's in the late morning/early afternoon. This allowed for
near perfect visibility at 80 to 90 miles all day. Wind began
coming from the NNW today, but it became light and variable
by mid-morning.    

Today's Observations:

7 A.M.
Weather: Sky clear 
Temperature: 64F; Dew Point: 51F; Wind: N at 5G10 kts,
Wind: Light
Sea-level pressure: 30.08 ins. Hg, rising, then more slowly 
Visibility: 80 miles 
6-hr Max temp: 64F
6-hr Min temp: 56F
24-hr Precip: 0.00 ins.  
BHO SA 1155 CLR 90 187/64/51/3505G10/008/ SKC WND LGT/ 51014 
10064 20056 

10 A.M.
Weather: Clear, few cumulus distant  E-SE and W-NW  
Temperature: 74F; Dew Point: 46F; Wind: ENE at 6G10 kts,
Wind: Light
Sea-level pressure: 30.11 ins. Hg, rising, then more quickly
Visibility: 80 miles  
3-hr Precip: 0.00 ins. 
BHO SA 1455 CLR 80 197/74/46/0706G10/011/ FEW CU DSNT E-SE 
AND W-NW WND LGT/ 8/100 51010 

1 P.M.
Weather: Clear, few cumulus distant S and WNW 
Temperature: 78F; Dew Point: 48F; Wind: NW at 6G15 kts,
Wind: Light
Sea-level pressure: 30.10 ins. Hg, falling, then more quickly 
Visibility: 80 miles
6-hr Max temp: 79F
6-hr Min temp: 64F
6-hr precip: 0.00 ins. 
BHO SA 1755 CLR 80 193/78/48/3206G15/010/ FEW CU S AND WNW 
WND LGT/ 8/100 58004 10079 10064 

SUMMARY FOR WEDNESDAY, JULY 18, 2018 

TEMPERATURE (DEGREES F)
MAX.....81   NORMAL.....81
MIN.....63   NORMAL.....63
MEAN....72   NORMAL.....72

DEPARTURE FROM 30-YEAR NORMAL..........................0
TOTAL DEPARTURE FOR THE MONTH........................+56 [+2.9 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............7   DEPARTURE..........-1
TOTAL COOLING UNITS FOR THE MONTH.............173   DEPARTURE.........+51
TOTAL COOLING UNITS FOR THE SEASON............332   DEPARTURE.........+81
TOTAL COOLING UNITS LAST SEASON TO DATE.......341   DEPARTURE..........-9

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................21 NW  AT 11:14 A.M.*
                   AERO.........................22 NW  AT 11:20 A.M.
                   ASOS.........................22 NW  AT 10:50 A.M.
                   DAVIS........................23 WNW AT 11:14 A.M. RMY 23
FASTEST MILE FOR YESTERDAY......................16 NNW AT 10:48 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE...................16 NW  AT 10:48 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................17 NW  AT 10:48 A.M. 
AVERAGE WIND SPEED AND DIRECTION..............11.0 NNW
                   ASOS.......................11.5
                   DAVIS.......................8.2 NNW [339 deg.]
* LAST OF MULTIPLE:        ADDITIONAL PEAK GUST 21 NNW AT 10:48 A.M.

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.13
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.65  DEPARTURE......+0.45
                         ASOS..............2.69 
TOTAL PRECIPITATION FOR THE YEAR..........32.82  DEPARTURE......+3.83
                         ASOS.............34.42

PRELIMINARY CLIMATE SUMMARY FOR JULY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/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

7/01 94/72/83/+13/0.00/667/73       21 ESE AERO 18 ESE RMY 19 
7/02 90/68/79/+9/0.00/858/94        21 S   AERO 21 S   RMY 22
7/03 94/69/82/+11/0.00/657/72       20 SSW AERO 18 SW  RMY 19 TSTM
7/04 89/73/81/+10/0.00/884/97       17 NE  AERO 15 NE  RMY 16
7/05 91/73/82/+11/0.00/865/95       29 SSW AERO 28 SSW RMY N/A
7/06 80/59/70/-1/0.56/018/02        37 NNW AERO 38 SW  RMY 40 TSTM
7/07 78/54/66/-5/0.00/900/99        22 N   AERO 18 N   RMY N/A 
7/08 83/57/70/-2/0.00/890/98        23 S   AERO 21 S   RMY 22  
7/09 88/60/74/+2/0.00/852/94        23 SW  AERO 23 SW  RMY 24 
7/10 91/63/77/+5/0.10/751/83        24 W   AERO 22 W   RMY N/A
7/11 73/62/68/-4/0.63/705/78        28 NE  AERO 25 NE  RMY 27 TSTM
7/12 77/56/67/-5/0.00/.../..        16 NW  AERO 15 NW  RMY N/A 
7/13 84/61/73/+1/0.00/.../..        23 SSE AERO 23 SSE RMY 24
7/14 80/61/71/-1/0.00/.../..        18 S   AERO 16 S   RMY 19
7/15 84/65/75/+3/T/.../..           16 S   AERO 15 S   RMY 14 
7/16 83/67/75/+3/0.00/.../..        23 S   AERO 23 S   RMY 23 
7/17 88/67/78/+6/1.34/.../..        31 SW  AERO 30 SW  RMY 32 TSTM 
7/18 81/63/72/0/0.02/.../..         21 NW  AERO 22 NW  RMY 23 

7/19 Low temp since midnight is 56F; normal low is now 63F

DAILY RECORDS FOR JULY 2018

07/01/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 72F, 
          TIES PREVIOUS RECORD OF 72F SET IN 1968

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

RECORDS FOR JULY 19
HIGH 96F IN 1977, 1991
LOW 50F IN 1890
PRECIP 1.10 INS IN 1951
WIND 63 MPH SSW IN 1982

RECORDS FOR JULY 20
HIGH 99F IN 1991
LOW 47F IN 1890
PRECIP 1.64 INS IN 1938
WIND 56e MPH SSW IN 1943

TODAY'S REPORT PREPARED BY: Kaitlin Geagan