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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, SEPTEMBER 14, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

MOSTLY CLOUDY, WARMER, DRY DAY ON TOP OF GREAT BLUE HILL...

Temperatures return to slightly above normal after a few 
below normal and cloudy days on top of Great Blue Hill. 
So far today we reached a max of 75F, which is 3 degrees 
above the daily normal of 72F. The skies began to clear 
today with a few breaks in the stratocumulus clouds during 
the day. Visibility varied again today. We began the day 
with undercast conditions covering Boston and ground fog 
in the area. This cleared as humidity lowered by 10:00 A.M. 
and we could see 70 miles, except to the east where fog 
still remained distant offshore with the same conditions 
at 1:00 P.M. The wind was light and variable today settling 
to coming from the NE by 1:00 P.M.  

Today's Observations:

7 A.M.
Weather: Broken stratocumulus, partial undercast 
conditions NNW-ENE 
Temperature: 65F; Dew Point: 64F; Wind: N at 5 kts,
Wind: Light 
Sea-level pressure: 30.30 ins. Hg, rising then steady        
Visibility: 20 miles, except NNW-ENE 5 miles, patches 
of ground fog below summit in all directions, distant 
fog ENE-NNW
6-hr Max temp: 65F
6-hr Min temp: 61F
24-hr Precip: Trace  
BHO SA 1155 E26 BKN 20 261/65/64/0105/030/ PARTIAL 
UNDERCAST CND NNW-ENE VSBY NNW-ENE 5 PTCHS GF BLO SMT 
ALQDS DSNT FG ENE-NNW WND LGT/ 8/500 51005 10065 20061

10 A.M.
Weather: Broken Stratocumulus, few towering cumulus
in all directions 
Temperature: 71F; Dew Point: 62F; Wind: ENE at 4 kts,
Wind: Light 
Sea-level pressure: 30.31 ins. Hg, steady then rising
Visibility: 70 miles, except NNE-ENE 40 miles, distant 
fog offshore NNE-ENE
3-hr Precip: 0.00 ins.  
BHO SA 1455 E30 BKN 70 263/71/62/0604/031/ FEW TCU ALQDS 
DSNT FG OFFSHR NNE-ENE VSBY 40 NNE-ENE WND LGT/ 8/500 
51002    

1 P.M.
Weather: Scattered cumulus, broken stratocumulus 
Temperature: 73F; Dew Point: 63F; Wind: ENE at 5 kts,
Wind: Light 
Sea-level pressure: 30.28 ins. Hg, falling, then more slowly     
Visibility: 70 miles, except NNE-ENE 40 miles, distant 
fog offshore NNE-ENE
6-hr Max temp: 75F
6-hr Min temp: 65F
6-hr Precip: Trace 
BHO SA 1755 15 SCT E40 BKN 70 254/73/63/0605/028/ DSNT FG 
OFFSHR NNE-ENE VSBY 40 NNE-ENE WND LGT/ 8/500 56009 10075 
20065
  
SUMMARY FOR THURSDAY, SEPTEMBER 13, 2018 

TEMPERATURE (DEGREES F)
MAX.....68   NORMAL.....73
MIN.....62   NORMAL.....56
MEAN....65   NORMAL.....64

DEPARTURE FROM 30-YEAR NORMAL.......................+1
TOTAL DEPARTURE FOR THE MONTH......................+39 [+2.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............0   DEPARTURE..........-3
TOTAL HEATING UNITS FOR THE MONTH..............18   DEPARTURE..........-7
TOTAL HEATING UNITS FOR THE SEASON.............18   DEPARTURE.........-32
TOTAL HEATING UNITS LAST SEASON TO DATE........50   DEPARTURE.........+57

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0  DEPARTURE..........-2
TOTAL COOLING UNITS FOR THE MONTH..............73  DEPARTURE.........+34
TOTAL COOLING UNITS FOR THE SEASON............826  DEPARTURE........+250
TOTAL COOLING UNITS LAST SEASON TO DATE.......634  DEPARTURE........+192

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY.....................21 NE  AT 6:09 A.M.
                   AERO..........................18 NE  AT 6:09 A.M.
                   ASOS..........................21 NE  AT 6:09 A.M.
                   DAVIS.........................20 NE  AT 6:08 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY.......................12 NE  AT 6:07 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE....................15 NE  AT 6:09 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE...................15 NNE AT 6:09 A.M.
AVERAGE WIND SPEED AND DIRECTION................5.2 NE
                   ASOS.........................5.5 
                   DAVIS........................5.5 ENE [DEG 63]   

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..........2.94  DEPARTURE......+1.33
                         ASOS..............2.95 
TOTAL PRECIPITATION FOR THE YEAR..........40.89  DEPARTURE......+4.44
                         ASOS.............42.47 

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/..../.../..        30 E   AERO 28 E   RMY 28
9/11 75/61/68/+3/..../.../..        23 E   AERO 21 E   RMY N/A TSTM 
9/12 69/63/66/+1/..../.../..        21 ENE AERO 21 ENE RMY 21  TSTM 
9/13 68/62/65/+1/..../.../..        21 NE  AERO 21 NE  RMY N/A TSTM 

9/14 Low temp since midnight is 61F; normal low is now 55F

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 14
HIGH 90F IN 1931
LOW 34F IN 1911
PRECIP 4.38 INCHES IN 1944 (Great Atlantic Hurricane in 1944)
PEAK GUST 96e MPH E IN 1944 (Great Atlantic Hurricane in 1944)

RECORDS FOR SEPTEMBER 15
HIGH 89F IN 1931
LOW 35F IN 1913
PRECIP 3.93 INCHES IN 1904 (Extra-tropical storm making landfall 
in New England on 9/15/1904 passing east of BHO and bringing a 
storm total of 4.11 inches 9/14-15/1904)
PEAK GUST 65e MPH NW, WSW IN 1944 (In the wake of Great Atlantic 
Hurricane)

TODAY'S REPORT PREPARED BY: Kaitlin Geagan