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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, SEPTEMBER 29, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

FOGGY START TO A THEN LESS CLOUDY AND SLIGHTLY
WARMER THAN NORMAL DAY...

Visibility this morning was limited to only 1/2 mile at
the 7:00 observation due to fog in the area, which 
cleared by the 10:00 observation, making for decent 70 mile
visibility that increased to 80 miles at the 1:00 P.M. 
observation. We experienced a drop in pressure after 10 A.M., 
leading to an increase in clouds from 1/8th of the sky being 
covered, to about half of the sky being covered. On this day 
in 1914, Great Blue Hill observed its lowest September 
temperature measured to date at 28F. In comparison, our low 
today since midnight has been 50F, 22 degrees higher. Our 
maximum temperature so far today is 70F, 3 degrees above our 
daily normal maximum of 67F.

Today's Observations:

7 A.M.
Weather: Fog 
Temperature: 51F; Dew Point: 51F; Wind: W at 7G15 kts  
Sea-level pressure: 30.14 ins. Hg, rising, then more quickly        
Visibility: 1/2 mile, fog
6-hr Max temp: 52F
6-hr Min temp: 50F
24-hr Precip: 0.26 ins.   
BHO SA 1155 W3 X 1/2F 207/51/51/2707G15/014/ FOG/ 8//// 53012 
10052 20050

10 A.M.
Weather: Clear, few cumulus in all directions
Temperature: 64F; Dew Point: 56F; Wind: WNW at 5 kts 
Wind: light 
Sea-level pressure: 30.17 ins. Hg, rising then falling
Visibility: 70 miles, distant haze in all directions 
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 216/64/56/3005/017/ FEW CU ALQDS DSNT HZ ALQDS
WND LGT/ 8/100 50009

1 P.M.
Weather: Scattered cumulus
Temperature: 70F; Dew Point: 56F; Wind: WNW at 4 kts
Wind: light
Sea-level pressure: 30.15 ins. Hg, falling, then more slowly     
Visibility: 80 miles 
6-hr Max temp: 70F
6-hr Min temp: 51F 
6-hr Precip: 0.00 ins.
BHO SA 1755 30 SCT 80 209/70/56/3004/015/ WND LGT/ 8/200 56007 
10070 20051
  
SUMMARY FOR FRIDAY, SEPTEMBER 28, 2018 

TEMPERATURE (DEGREES F)
MAX.....56   NORMAL.....67
MIN.....52   NORMAL.....50
MEAN....54   NORMAL.....58

DEPARTURE FROM 30-YEAR NORMAL.......................-4
TOTAL DEPARTURE FOR THE MONTH......................+75 [+2.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............11   DEPARTURE.........+3
TOTAL HEATING UNITS FOR THE MONTH..............76   DEPARTURE........-25
TOTAL HEATING UNITS FOR THE SEASON.............76   DEPARTURE........-50
TOTAL HEATING UNITS LAST SEASON TO DATE........69   DIFFERENCE........+7

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0  DEPARTURE..........-1
TOTAL COOLING UNITS FOR THE MONTH.............110  DEPARTURE.........+51
TOTAL COOLING UNITS FOR THE SEASON............863  DEPARTURE........+267
TOTAL COOLING UNITS LAST SEASON TO DATE.......707  DIFFERENCE.......+156

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................24 NNE AT 10:51 A.M.
                   AERO.........................21 NNE AT 12:22 P.M.
                   ASOS.........................24 NNE AT 10:51 A.M.
                   DAVIS........................24 NE  AT 10:50 A.M. RMY 23
FASTEST MILE FOR YESTERDAY......................15 NE  AT 7:45  A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................16 ENE AT 7:46  A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................16 ENE AT 7:46  A.M.
AVERAGE WIND SPEED AND DIRECTION...............8.3 NNE
                   ASOS........................8.7
                   DAVIS.......................8.5 NE [37 deg.]   

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.26  DEPARTURE......+0.11
                         ASOS..............0.27
TOTAL PRECIPITATION FOR THE MONTH..........9.13  DEPARTURE......+5.37
                         ASOS..............9.40 
TOTAL PRECIPITATION FOR THE YEAR..........47.08  DEPARTURE......+8.48
                         ASOS.............48.92 

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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

9/01 75/58/67/-1/0.00/521/66        17 NE  AERO 15 NE  RMY 16 
9/02 83/61/72/+4/0.00/684/87        20 SSW AERO 18 SSW RMY N/A 
9/03 92/68/80/+13/0.00/650/83       24 WSW AERO 22 WSW RMY 25
9/04 88/70/79/+12/0.00/695/89       17 W   AERO 16 W   RMY 17 
9/05 89/67/78/+11/0.00/638/82       23 SSW AERO 23 SSW RMY 25 
9/06 92/70/81/+14/0.56/488/63       29 NNW AERO 29 NNW RMY N/A TSTM
9/07 70/63/67/+1/0.01/000/00        24 NE  AERO 22 NE  RMY N/A 
9/08 68/54/61/-5/0.00/031/04        22 NE  AERO 18 NE  RMY 21
9/09 61/53/57/-9/0.00/000/00        23 NE  AERO 21 NE  RMY N/A
9/10 62/56/59/-6/..../000/00        30 E   AERO 28 E   RMY 28
9/11 75/61/68/+3/..../000/00        23 E   AERO 21 E   RMY N/A TSTM 
9/12 69/63/66/+1/..../000/00        21 ENE AERO 21 ENE RMY 21  TSTM 
9/13 68/62/65/+1/..../091/12        21 NE  AERO 21 NE  RMY N/A TSTM 
9/14 75/61/68/+4/..../233/31        13 NE  AERO 12 ENE RMY 12 
9/15 76/62/69/+5/0.01/218/29        14 SW  AERO 13 SW  RMY 13
9/16 84/61/73/+10/..../695/93       15 S   AERO 14 S   RMY N/A
9/17 82/64/73/+10/..../372/50       22 SSW AERO 22 SSW RMY N/A
9/18 74/67/71/+9/..../000/00        31 SSW AERO 30 SSW RMY N/A TSTM
9/19 66/57/62/0/..../007/01         28 NE  AERO 25 NE  RMY 26
9/20 63/55/59/-3/..../.../..        22 NE  AERO 21 NE  RMY 19
9/21 70/55/63/+2/..../.../..        37 SSW AERO 37 SSW RMY 41
9/22 70/51/61/0/..../.../..         37 SW  AERO 36 SW  RMY 30
9/23 60/47/54/-6/..../.../..        14 N   AERO 13 N   RMY N/A 
9/24 55/50/53/-7/..../.../..        37 ENE AERO 35 ENE RMY 35
9/25 68/51/60/0/..../.../..         36 SE  AERO 37 SE  RMY 38
9/26 79/66/73/+14/..../.../..       35 SSW AERO 37 SSW RMY 37
9/27 66/56/61/+2/..../.../..        26 NNE AERO 25 NNE RMY 28
9/28 56/52/54/-4/..../.../..        24 NNE AERO 21 NNE RMY 23

9/29 Low temp since midnight is 50F; normal low is now 49F

DAILY RECORDS FOR SEPTEMBER

09/04/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F,
          BREAKS PREVIOUS RECORD OF 68F SET IN 1937 AND 1959

09/06/18: DAILY RECORD HIGH MAXIMUM TEMPERATURE OF 92F,
          TIES PREVIOUS RECORD OF 92F SET IN 1900 

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

RECORDS FOR SEPTEMBER 29
HIGH 85F IN 1952
LOW 28F IN 1914 (SEPTEMBER MINIMUM RECORD)
PRECIP 2.61 INCHES IN 1907
PEAK GUST 62 MPH S IN 2005

RECORDS FOR SEPTEMBER 30
HIGH 84F IN 1986
LOW 31F IN 1992
PRECIP 2.44 INCHES IN 2015
PEAK GUST 58 MPH SSE IN 1999

TODAY'S REPORT PREPARED BY: Samantha Richard