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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, SEPTEMBER 7, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

A WIND SHIFT TO NORTHEASTERLY WIND BRINGS MUCH COOLER 
TEMPERATURES TO GREAT BLUE HILL...  

The high maximum temperature yesterday was a record-tying 
daily temperature of 92F. The previous daily high maximum 
record of 92F was originally set back in 1900. Around 3:30
P.M. EST the wind shifted from the SW to the NNW causing
temperatures to drop about 15 degrees between 3:00-4:00 
P.M. Soon after thunderstorms with heavy rain, and high 
wind were observed. We measured 0.56 inches this morning 
from the storms. With this being the first rainfall in the 
month of September we are still 0.15 ins below normal for 
rainfall this month. The wind gusted to 25 kts (29 MPH) 
during the storm. Today wind from the NE was breezy in the 
morning but became light in the afternoon. Temperatures were 
below normal today with a high so far of 70F which happened 
just after midnight. Skies were overcast with on and off rain 
and drizzle showers today. So far we have measured an 
additional 0.01 ins of precipitation by 1:00 P.M. Visibility 
increased from 15 miles to 45 miles by 10:00 A.M. and did 
not improve by the 1:00 P.M. observation.

PRELIMINARY STATS FOR AUGUST 2018
 
TEMPERATURE, Deg. F
Avg. Max. 82.4 [+3.2]
Avg. Min. 66.4 [+4.6]
Mean      74.4 [+3.9]
24-hour corrected mean: 73.4
Max. for month: 94F on 29th
Min. for month: 59F on 24th, 25th, and 26th
 
COOLING DEGREE DAYS
Total heating units:   298 [+112] 
Total for the season:  753 [+216]
Total for last season: 607

PRECIPITATION, Inches
Total: 3.94 [-0.09]
Greatest in 24 hrs: 1.31 on the 3rd-4th 

WIND, mph
Avg. uncorrected wind speed: 9.6
Avg. corrected wind speed:   10.2
Prevailing wind direction:   SW at 13%
Peak gust and direction: 35 NW on 3rd, 35 WNW on 22nd

SUNSHINE:
Campbell-Stokes card minutes: 14304 minutes of possible 24780 or 58%
Astronomical total minutes:   14856 minutes of possible 25749 or 58%

BHO Warmest August Mean Temperature (24-hour adjusted), deg F (1885-2018):

1) 74.1 in 2016
2) 73.4 in 2018
3) 72.6 in 2012
4) 72.5 in 1988
5) 72.4 in 2015

BHO Warmest August Average Maximum Temperature, deg F (1885-2018):

1) 85.1 in 2016
2) 83.2 in 2005
3) 83.1 in 1949
4) 82.6 in 2015
5) 82,5 in 1988
   82.5 in 2002
   82.5 in 2012
8) 82.4 in 1944
   82.4 in 2018

BHO Warmest August Average Minimum Temperature, deg F (1885-2018):

1) 66.3 in 2018
2) 65.0 in 2016
3) 64.9 in 2001
4) 64.6 in 2012
5) 64.4 in 2005
   64.4 in 2015

BHO Warmest August Monthly Minimum Temperature, deg F (1885-2018):

1) 59 in 2018
2) 58 in 1939
   58 in 2015
4) 57 in 1901
   57 in 2001

BHO Greatest August Water Vapor Pressure, mb (1932-2018):

1) 22.5 in 2018
2) 21.6 in 1937
3) 21.5 in 1988
4) 21.0 in 1955
   21.0 in 2009
6) 20.9 in 2003

Today's Observations:

7 A.M.
Weather: Light rain, overcast nimbostratus with a break in the
overcast NNW, few stratocumulus distant S, virga WSW-NNW 
Temperature: 64F; Dew Point: 57F; Wind: NE AT 8G14 kts
Sea-level pressure: 30.22  ins. Hg, rising then steady    
Visibility: 15 miles, distant fog in all directions
6-hr Max temp: 69F
6-hr Min temp: 63F
24-hr Precip: 0.56 ins.  
BHO SA 1155 E40 OVC 15R- 235/64/57/0508G14/022/ FEW SC DSNT S 
BINOVC NNW VIRGA WSW-NNW DSNT FG ALQDS R-B10/ 8/52/ 51007 MANUAL 
70056 ASOS 70053 10069 20063 

10 A.M.
Weather: Very light drizzle, scattered stratocumulus, broken
altocumulus, overcast nimbostratus  
Temperature: 66F; Dew Point: 58F; Wind: NE at 10G14 kts
Sea-level pressure: 30.23 ins. Hg, falling then rising  
Visibility: 45 miles, distant fog in all directions 
3-hr Precip: Trace
BHO SA 1455 50 SCT E80 BKN E200 OVC 45L- 236/66/58/0410G14/023/ 
PCPN VRY LGT DSNT FG ALQDS/ 8/52/ 53001 MANUAL 600// 

1 P.M.
Weather: Scattered stratocumulus, broken altocumulus,
overcast altostratus 
Temperature: 67F; Dew Point: 59F; Wind: NE at 6 kts,
Wind: Light
Sea-level pressure: 30.20 ins. Hg, falling, then more rapidly   
Visibility: 45 miles, distant fog in all directions 
6-hr Max temp: 67F
6-hr Min temp: 63F
6-hr Precip: 0.00 ins.
BHO SA 1755 50 SCT E90 BKN E150 OVC 45 227/67/59/0406/020/ 
SUN DMLY VSBL DSNT FG ALQDS WND LGT/ 8/51/ 58009 MAUNUAL 6001/   
10067 20063

SUMMARY FOR THURSDAY, SEPTEMBER 6, 2018 

TEMPERATURE (DEGREES F)
MAX.....92   NORMAL.....75
MIN.....70   NORMAL.....59
MEAN....81   NORMAL.....67

DEPARTURE FROM 30-YEAR NORMAL......................+14
TOTAL DEPARTURE FOR THE MONTH......................+53 [+8.6 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY..............16  DEPARTURE.........+13
TOTAL COOLING UNITS FOR THE MONTH..............67  DEPARTURE.........+46
TOTAL COOLING UNITS FOR THE SEASON............820  DEPARTURE........+263
TOTAL COOLING UNITS LAST SEASON TO DATE.......620  DEPARTURE........+200

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY.....................29 NNW AT 3:30 P.M.
                   AERO..........................29 NNW AT 3:30 P.M.
                   ASOS..........................31 NNW AT 3:30 P.M.
                   DAVIS.........................29 W   AT 3:32 P.M. RMY 25
FASTEST MILE FOR YESTERDAY.......................20 NNW AT 3:31 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE....................21 WNW AT 4:01 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE...................21 W   AT 3:31 P.M.
AVERAGE WIND SPEED AND DIRECTION................9.8 SW
                   ASOS........................10.1
                   DAVIS.......................10.4 S [188 DEG]  

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.56  DEPARTURE......+0.43
                         ASOS..............0.53
TOTAL PRECIPITATION FOR THE MONTH..........0.56  DEPARTURE......-0.15
                         ASOS..............0.53 
TOTAL PRECIPITATION FOR THE YEAR..........38.51  DEPARTURE......+2.96
                         ASOS.............40.05

PRELIMINARY CLIMATE SUMMARY FOR AUGUST 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

8/1  82/66/74/+2/T/199/23           31 S   AERO 30 S   RMY 31
8/2  92/74/83/+11/0.00/761/88       30 SW  AERO 28 SW  RMY 31 
8/3  88/74/81/+9/0.19/492/57        35 NW  AERO 32 NW  RMY 35 TSTM
8/4  82/69/76/+4/1.16/301/35        28 SW  AERO 25 SW  RMY 30 TSTM
8/5  89/66/78/+6/0.00/815/95        20 W   AERO 18 W   RMY 19
8/6  92/71/82/+10/0.00/822/96       20 W   AERO 16 WSW RMY N/A
8/7  92/73/83/+11/0.00/682/80       25 S   AERO 23 S   RMY 26
8/8  88/71/80/+8/0.70/460/54        25 SSW AERO 25 SSW RMY N/A TSTM 
8/9  86/70/78/+6/0.07/509/60        29 SW  AERO 28 SW  RMY N/A TSTM
8/10 85/66/76/+5/0.00/651/77        17 NW  AERO 16 NW  RMY N/A      
8/11 70/66/68/-3/0.34/000/00        18 SE  AERO 17 SE  RMY 18
8/12 73/66/70/-1/0.39/000/00        23 NNE AERO 18 NNE RMY 21
8/13 69/64/67/-4/0.17/000/00        23 ENE AERO 21 ENE RMY 21 
8/14 83/69/76/+5/0.00/502/60        25 S   AERO 23 S   RMY 24 
8/15 86/68/77/+6/0.00/509/61        20 W   AERO 17 W   RMY 19 
8/16 87/70/79/+8/0.00/515/62        20 W   AERO 18 W   RMY 20 
8/17 83/67/75/+4/0.00/531/64        23 SSW AERO 23 SSW RMY N/A
8/18 83/63/73/+2/0.50/165/20        31 NE  AERO 30 NE  RMY 33 TSTM 
8/19 68/62/65/-5/0.03/527/64        30 NE  AERO 30 NE  RMY 32
8/20 72/61/67/-3/0.00/591/72        28 ENE AERO 25 ENE RMY 27 
8/21 69/61/65/-5/T/155/19           20 ESE AERO 17 ESE RMY N/A 
8/22 82/62/72/+2/0.38/326/40        35 WNW AERO 35 WNW RMY 35 
8/23 76/60/68/-2/0.01/187/23        25 NW  AERO 23 NW  RMY 27
8/24 82/59/71/+1/0.00/754/93        20 SSE AERO 18 SSE RMY 20
8/25 80/59/70/+1/0.00/735/91        20 S   AERO 18 S   RMY 20
8/26 81/59/70/+1/0.00/716/89        21 SSW AERO 20 SSW RMY 21
8/27 86/67/77/+8/0.00/706/88        21 WNW AERO 18 WNW RMY 18
8/28 93/72/83/+14/0.00/672/84       25 WSW AERO 25 WSW RMY 28
8/29 94/75/85/+16/0.00/399/50       25 SW  AERO 24 SW  RMY 27 
8/30 88/67/78/+10/0.00/564/71       23 ENE AERO 21 ENE RMY N/A
8/31 72/60/66/-3/0.00/610/77        24 ENE AERO 23 ENE RMY N/A

DAILY RECORDS FOR AUGUST 2018

08/03/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 74F, 
          BREAKS PREVIOUS RECORD OF 71F SET IN 1928, 1969, AND 1979

08/07/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 73F, 
          BREAKS PREVIOUS RECORD OF 72F SET IN 1988

08/29/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 75F, 
          BREAKS PREVIOUS RECORD OF 74F SET IN 1948

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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

9/1 75/58/67/-1/0.00/.../..        17 NE  AERO 15 NE  RMY 16        
9/2 83/61/72/+4/0.00/.../..        20 SSW AERO 18 SSW RMY N/A 
9/3 92/68/80/+13/0.00/.../..       24 WSW AERO 22 WSW RMY 25
9/4 88/70/79/+12/0.00/.../..       17 W   AERO 16 W   RMY 17 
9/5 89/67/78/+11/0.00/.../..       23 SSW AERO 23 SSW RMY 25 
9/6 92/70/81/+14/..../.../..       29 NNW AERO 29 NNW RMY N/A TSTM

9/7 Low temp since midnight is 63F; normal low is now 58F

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 7
HIGH 92F IN 2007, 2015
LOW 40F IN 1888
PRECIP 2.95 INCHES IN 1891
PEAK GUST 58e MPH W IN 1941

RECORDS FOR SEPTEMBER 8
HIGH 97F IN 2015
LOW 42F IN 1978
PRECIP 1.51 INCHES IN 2011
PEAK GUST 45 MPH S IN 2012

TODAY'S REPORT PREPARED BY: Kaitlin Geagan