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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, SEPTEMBER 13, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

SKIES REMAINS MOSTLY CLOUDY TODAY AFTER YESTERDAY
AFTERNOON AND TODAY'S EARLY MORNING THUNDERSTORMS...

Skies remained mostly covered with stratus clouds today
producing light drizzle at times. Yesterday afternoon 
and early this morning thunderstorms passed by Great 
Blue Hill and we measured 0.95 ins. of precipitation 
this morning at the 7:00 A.M. observation. So far we 
have measured an additional trace from a few short drizzly
showers by 1:00 P.M. today. High temperature remain below 
normal with a max so far of 67F. This is 6 degrees below 
the daily normal of 73F. Overnight temperatures are still 
above normal with a low of 62F since midnight. This is 6 
degrees above the daily normal of 56F. Wind remains from the 
ENE and was light for most of the day. Visibility varied from 
5-25 miles today caused by fog and stratus fractus drifting 
below the summit all day. Humidity was high today and dropped 
from 99% to 87% at 1:00 P.M. This allowed for the best 
visibility of 25 miles at the 1:00 P.M. observation.

Today's Observations:

7 A.M.
Weather: Overcast stratus, few stratus fractus drifting
below the summit  
Temperature: 62F; Dew Point: 62F; Wind: E at 7G12 kts
Sea-level pressure: 30.33 ins. Hg, falling then rising       
Visibility: 20 miles, except ENE 5 miles and ENE-SSW 10 miles,
distant fog in all directions 
6-hr Max temp: 63F
6-hr Min temp: 62F
24-hr Precip: 0.95 ins.  
BHO SA 1155 E15 OVC 20 272/62/62/0807G12/033/ FEW STFRA 
DRFTG BLO SMT VSBY 5 ENE AND 10 ENE-SSW DSNT FG ALQDS/ 
8/6// 53009 MANUAL 70095 ASOS 70097 10063 20062

10 A.M.
Weather: Very light drizzle, broken stratocumulus, overcast 
nimbostratus, few stratus fractus drifting below the summit 
Temperature: 67F; Dew Point: 64F; Wind: ENE at 6 kts,
Wind: Light 
Sea-level pressure: 30.34 ins. Hg, rising then falling
Visibility: 20 miles, except 10 miles SSE-SSW and NNW-NNE, distant
fog in all directions 
3-hr Precip: Trace  
BHO SA 1455 E20 BKN E35 OVC 20L- 275/67/64/0706/034/ FEW STFRA 
DRFTG BLO SMT VSBY 10 SSE-SSW AND NNW-NNE PCPN VRY LGT DSNT FG 
ALQDS SUN DMLY VSBL WND LGT/ 8/52/ 50003 MANUAL 600//   

1 P.M.
Weather: Scattered stratocumulus, overcast stratus, break
in overcast NNE  
Temperature: 67F; Dew Point: 63F; Wind: ENE at 4 kts,
Wind: Light 
Sea-level pressure: 30.32 ins. Hg, falling, then more slowly     
Visibility: 25 miles, distant fog in all directions 
6-hr Max temp: 67F
6-hr Min temp: 62F
6-hr Precip: Trace 
BHO SA 1755 12 SCT E20 OVC 25 267/67/63/0604/032/ BINOVC NNE 
DSNT FG ALQDS WND LGT/ 8/6// 56008 MANUAL 600// 10067 20062 
  
SUMMARY FOR WEDNESDAY, SEPTEMBER 12, 2018 

TEMPERATURE (DEGREES F)
MAX.....69   NORMAL.....73
MIN.....63   NORMAL.....56
MEAN....66   NORMAL.....65

DEPARTURE FROM 30-YEAR NORMAL.......................+1
TOTAL DEPARTURE FOR THE MONTH......................+38 [+3.0 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............1  DEPARTURE..........-1
TOTAL COOLING UNITS FOR THE MONTH..............73  DEPARTURE.........+36
TOTAL COOLING UNITS FOR THE SEASON............826  DEPARTURE........+252
TOTAL COOLING UNITS LAST SEASON TO DATE.......627  DEPARTURE........+199

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............0   DEPARTURE..........-3
TOTAL HEATING UNITS FOR THE MONTH..............18   DEPARTURE..........-4
TOTAL HEATING UNITS FOR THE SEASON.............18   DEPARTURE.........-29
TOTAL HEATING UNITS LAST SEASON TO DATE........47   DEPARTURE.........+57

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY.....................21 ENE AT 8:47 A.M.
                   AERO..........................21 ENE AT 8:29 A.M.
                   ASOS..........................22 ENE AT 8:47 A.M.
                   DAVIS.........................21 ENE AT 8:29 A.M. RMY 21
FASTEST MILE FOR YESTERDAY.......................15 ENE AT 1:57 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE....................16 ENE AT 1:58 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE...................16 E   AT 1:57 P.M.
AVERAGE WIND SPEED AND DIRECTION................8.2 ENE
                   ASOS.........................8.9 
                   DAVIS........................8.5 ENE [DEG 58]   

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.95  DEPARTURE......+0.82
                         ASOS..............0.97
TOTAL PRECIPITATION FOR THE MONTH..........2.94  DEPARTURE......+1.46
                         ASOS..............2.95 
TOTAL PRECIPITATION FOR THE YEAR..........40.89  DEPARTURE......+4.57
                         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/.../..        17 NE  AERO 15 NE  RMY 16        
9/02 83/61/72/+4/0.00/.../..        20 SSW AERO 18 SSW RMY N/A 
9/03 92/68/80/+13/0.00/.../..       24 WSW AERO 22 WSW RMY 25
9/04 88/70/79/+12/0.00/.../..       17 W   AERO 16 W   RMY 17 
9/05 89/67/78/+11/0.00/.../..       23 SSW AERO 23 SSW RMY 25 
9/06 92/70/81/+14/0.56/.../..       29 NNW AERO 29 NNW RMY N/A TSTM
9/07 70/63/67/+1/0.01/.../..        24 NE  AERO 22 NE  RMY N/A 
9/08 68/54/61/-5/0.00/.../..        22 NE  AERO 18 NE  RMY 21
9/09 61/53/57/-9/0.00/.../..        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 Low temp since midnight is 62F; normal low is now 56F

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 13
HIGH 91F IN 1957
LOW 40F IN 1985
PRECIP 3.10 INCHES IN 1987
PEAK GUST 44 MPH WNW IN 1986

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)

TODAY'S REPORT PREPARED BY: Kaitlin Geagan