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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, SEPTEMBER 30, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

DROPPING PRESSURE LEADS TO AN INCREASE IN CLOUDS
AS THE DAY PROCEEDS...

The sky became progressively cloudier throughout the 
day, as pressure began to drop after the 7:00 
observation this morning. The high temperature for 
today so far has been 66F, the same as our normal
high. Wind has remained fairly consistent, at 
around 10 kts, and coming from the north west all day. 
Our low since midnight was 48F, 1 degree below our 
normal low temperature of 49F.

Today's Observations:

7 A.M.
Weather: Clear, few cirrus in all directions
Temperature: 51F; Dew Point: 44F; Wind: NW at 9G12 kts  
Sea-level pressure: 30.33 ins. Hg, rising steadily        
Visibility: 70 miles, distant haze in all directions
6-hr Max temp: 52F
6-hr Min temp: 48F
24-hr Precip: 0.00 ins.   
BHO SA 1155 CLR 70 272/51/44/3209G12/033/ FEW CI ALQDS 
DSNT HZ ALQDS/ 8/001 53011 10052 20048

10 A.M.
Weather: Clear, few cumulus NW-N few cirrostratus in all
directions 
Temperature: 61F; Dew Point: 59F; Wind: NW at 3 kts 
Wind: light 
Sea-level pressure: 30.35 ins. Hg, rising then falling
Visibility: 80 miles 
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 80 277/61/59/2803/035/ FEW CU NW-N FEW 
CS ALQDS WND LGT/ 8/105 50005

1 P.M.
Weather: Scattered cirrocumulus
Temperature: 65F; Dew Point: 44F; Wind: W at 8G14 kts
Sea-level pressure: 30.32 ins. Hg, falling, then more slowly     
Visibility: 70 miles 
6-hr Max temp: 66F
6-hr Min temp: 51F 
6-hr Precip: 0.00 ins.
BHO SA 1755 250 SCT 250 70 268/65/44/2708G14/032/ FEW CU ALQDS 
DSNT HZ ALQDS/ 8/109 56009 10066 20051
  
SUMMARY FOR SATURDAY, SEPTEMBER 29, 2018 

TEMPERATURE (DEGREES F)
MAX.....71   NORMAL.....67
MIN.....50   NORMAL.....49
MEAN....61   NORMAL.....58

DEPARTURE FROM 30-YEAR NORMAL.......................+3
TOTAL DEPARTURE FOR THE MONTH......................+78 [+2.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............4   DEPARTURE.........-4
TOTAL HEATING UNITS FOR THE MONTH..............80   DEPARTURE........-29
TOTAL HEATING UNITS FOR THE SEASON.............80   DEPARTURE........-54
TOTAL HEATING UNITS LAST SEASON TO DATE........78   DIFFERENCE........+2

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....................20 NW  AT 3:44  P.M.
                   AERO.........................18 NW  AT 3:41  P.M.
                   ASOS.........................19 NW  AT 3:43  P.M.
                   DAVIS........................19 NNW AT 10:50 A.M. RMY 20
FASTEST MILE FOR YESTERDAY......................12 NW  AT 3:41  P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................13 NW  AT 11:05 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................14 NW  AT 3:44  P.M.
AVERAGE WIND SPEED AND DIRECTION...............8.4 NW
                   ASOS........................8.6
                   DAVIS.......................9.0 WNW [296 deg.]   

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..........9.13  DEPARTURE......+5.22
                         ASOS..............9.40 
TOTAL PRECIPITATION FOR THE YEAR..........47.08  DEPARTURE......+8.33
                         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 71/50/61/+3/..../.../..        20 NW  AERO 18 NW  RMY 20

9/30 Low temp since midnight is 48F; 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 30
HIGH 84F IN 1986
LOW 31F IN 1992
PRECIP 2.44 INCHES IN 2015
PEAK GUST 58 MPH SSE IN 1999

RECORDS FOR OCTOBER 1
HIGH 85F IN 1927
LOW 30F IN 1992
PRECIP 1.63 INCHES IN 2014
PEAK GUST 68e MPH SSE IN 1977

TODAY'S REPORT PREPARED BY: Samantha Richard