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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, OCTOBER 17, 2017  
ALL TIMES ARE IN EASTERN STANDARD TIME

CHILLY START TO A CLEAR DRY DAY

With high pressure in the area we had a clear day
with a few distant cumulus clouds at each observation. 
Humidity dropped from 83% at 7:00 AM EST to 34% 
by 1:00 PM EST. We observed low dew points and relative 
humidity, which made for excellent  visibility at 80 miles 
all day. Winds coming from the NW brought cooler 
temperatures with an overnight minimum of 35F, which is 
below the normal daily minimum of 42F. Winds became light 
and variable today around 8:00 AM EST.  

Today's Observations:

7 A.M.
Weather: Clear, few distant cumulus NNE-SE
Temperature: 37F; Dew Point: 32F; Wind: NNW at 12 kts
Sea-level pressure: 30.29 ins. Hg, rising, then more quickly 
Visibility: 80 miles 
6-hr Max temp: 38F
6-hr Min temp: 35F
24-hr precip: 0.00 ins. 
BHO SA 1155 CLR 80 258/37/32/3312/029/ FEW DSNT CU NNE-SE/ 
8/100 53022 10038 20035

10 A.M.
Weather: Clear, few distant cumulus NNE-SSE 
Temperature: 49F; Dew Point: 31F; Wind: NNW at 4 kts,
Wind: Light
Sea-level pressure: 30.31 ins. Hg, rising then falling
Visibility: 80 miles
BHO SA 1455 CLR 80 263/49/31/E3304/031/ FEW DSNT CU NNE-SSE WND 
LGT/ 8/100 50005 

1 P.M. 
Weather: Clear, few distant cumulus NNW and W-SSW  
Temperature: 53F; Dew Point: 26F; Wind: W at 6 kts,
Wind: Light
Sea-level pressure: 30.27 ins. Hg, falling unsteadily 
Visibility: 80 miles
6-hr Max temp: 54F 
6-hr Min temp: 37F
BHO SA 1755 CLR 80 250/53/26/2806/027/ FEW DSNT CU NNW AND 
W-SSW WND LGT/ 8/100 58013 10054 20037 

SUMMARY FOR MONDAY, OCTOBER 16, 2017
 
TEMPERATURE (DEGREES F)
MAX.....66   NORMAL.....60
MIN.....39   NORMAL.....43
MEAN....53   NORMAL.....51

DEPARTURE FROM 30-YEAR NORMAL.........................+2
TOTAL DEPARTURE FOR THE MONTH.......................+123 [+7.5 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0   DEPARTURE...........0
TOTAL COOLING UNITS FOR THE MONTH..............20   DEPARTURE.........+16
TOTAL COOLING UNITS FOR THE SEASON............727   DEPARTURE........+126
TOTAL COOLING UNITS LAST SEASON TO DATE.......894   DEPARTURE........-167

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............12   DEPARTURE..........-2
TOTAL HEATING UNITS FOR THE MONTH..............69   DEPARTURE........-109
TOTAL HEATING UNITS FOR THE SEASON............162   DEPARTURE........-158
TOTAL HEATING UNITS LAST SEASON TO DATE.......223   DEPARTURE.........-61

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................28  NNW AT   8:34 P.M. **
                   AERO........................25  NNW AT  12:07 A.M.
                   ASOS........................27  SW  AT  12:01 A.M.
                   DAVIS.......................29  SSW AT  12:00 A.M.   RMY 29 
FASTEST MILE FOR YESTERDAY.....................22  SW  AT  12:07 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................23  SW  AT  12:01 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE.................23  SSW AT  12:01 A.M.
AVERAGE WIND SPEED AND DIRECTION.............12.9  NW
                   ASOS......................12.3
                   DAVIS.....................12.1  NW  [315 DEG.]
** Last of multiple peak gust

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.15
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........0.50  DEPARTURE......-1.72
                         ASOS..............0.50
TOTAL PRECIPITATION FOR THE YEAR..........42.36  DEPARTURE......+1.06
                         ASOS...............N/A ***
*** ASOS annual total not available due to erroneous readings


PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 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

10/1  65/42/54/-3/0.00/697/99               18 WNW AERO 16 NW  RMY N/A
10/2  65/46/56/-1/0.00/687/98               21 NNW AERO 21 NNW RMY 21
10/3  67/50/59/+3/0.00/677/97               21 S   AERO 21 S   RMY N/A
10/4  75/50/63/+7/0.00/660/95               30 SSW AERO 30 SW  RMY 32
10/5  79/60/70/+14/0.00/.../..              28 SW  AERO 26 SW  RMY N/A
10/6  73/57/65/+10/T/.../..                 15 NW  AERO 14 NW  RMY 15
10/7  75/59/67/+12/T/.../..                 29 S   AERO 30 SSW RMY N/A
10/8  71/67/69/+15/0.23/.../..              33 S   AERO 36 SSW RMY 37
10/9  71/68/70/+16/0.22/.../..              43 S   AERO 41 S   RMY 45
10/10 76/61/69/+15/0.00/.../..              21 WNW AERO 20 WNW RMY 21 
10/11 68/55/62/+9/0.00/.../..               29 ENE AERO 25 ENE RMY 29 
10/12 58/48/50/0/T/.../..                   30 NE  AERO 28 ENE RMY 30 
10/13 64/48/56/+3/0.00/.../..               20 E   AERO 16 E   RMY 17
10/14 66/54/60/+8/.../.../..                15 SSE AERO 13 SSE RMY 13 
10/15 72/58/65/+13/.../.../..               39 SSW AERO 36 SSW RMY 40 
10/16 66/39/53/+2/.../.../..                28 NNW AERO 25 NNW RMY 29

10/17 Low temp since midnight is 35F; normal low is now 42F

DAILY RECORDS FOR OCTOBER

10/8/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 67F,
         BREAKS PREVIOUS RECORD OF 60F SET IN 1944

10/9/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 68F,
         BREAKS PREVIOUS RECORD OF 61F SET IN 2011

10/9/17: MONTHLY RECORD HIGH MINIMUM TEMPERATURE OF 68F,
         BREAKS PREVIOUS RECORD OF 67F SET ON OCTOBER 13, 1990
         AND TIED ON OCTOBER 8, 2017

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

RECORDS FOR OCTOBER 17
HIGH 86F IN 1947
LOW 25F IN 1886
PRECIP 1.87 INCHES IN 1989
SNOWFALL TRACE IN 1970
PEAK GUST 55 MPH NE IN 1964

RECORDS FOR OCTOBER 18
HIGH 82F IN 1908
LOW 26F IN 1939
PRECIP 2.79 INCHES IN 1975
SNOWFALL 3.0 INCHES IN 2009
PEAK GUST 66 MPH S IN 1967

TODAY'S REPORT PREPARED BY: Kaitlin Geagan