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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, SEPTEMBER 10, 2015 
ALL TIMES ARE IN EASTERN STANDARD TIME

ANOTHER RECORD SETTING DAY ON GREAT BLUE HILL:

**92F MAXIMUM TEMPERATURE WEDNESDAY SETS NEW 
DAILY RECORD, SURPASSING 91F SET BACK IN 2002**

**70F HIGH MINIMUM TEMPERATURE WEDNESDAY SETS NEW
DAILY RECORD, SURPASSING 69F SET IN BACK IN 1999**

SECOND OFFICIAL SEPTEMBER 'HEAT WAVE' SINCE 1895

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Yesterday afternoon's 1:00 PM EST observation recorded
a maximum temperature of 92F, breaking the previous record
of 91F, set back in 2002. On back to back days, both the Tuesday
and Wednesday, the minimum temperature of 70F broke previous
record high minimum temperatures of 69F, both previously set
in 1999. 

The period from September 7th-9th was the second September heat 
wave in 130 years, but it was the hottest three-day period on
record to occur in September. 

The searing heat has finally broken this morning, although
unseasonable warmth still remains with building humidity.
By this morning's 7:00 AM EST observation only a trace of 
rain had fallen from a brief light rain shower with heavier
rain showers in the region.

By the 1:00 PM EST observation a light rain shower had quickly
developed into a heavy downpour, dropping 0.07 inches of new
rain before the precipitation can was changed. Winds had shifted
to the NE pumping in much cooler air. Temperatures had dropped
to 64F at the time of the observation. 


BHO Highest September Daily Maximum Temperature, deg F (1885-2015)

1) 99 on 2 Sep 1953
2) 97 on 8 Sep 2015
3) 95 on 3 Sep 1929
4) 93 on 23 Sep 1895
   93 on 1 Sep 1969
   93 on 11 Sep 1983
   93 on 8 Sep 2007
   93 on 1 Sep 2010
   93 on 2 Sep 2010
   93 on 11 Sep 2013


Today's Observations:

7 A.M.
Weather: Rain shower begins 6:12 AM, ends 6:25 AM,
showers distant SSE-WSW, few stratus fractus distant
ESE-S, broken altocumulus, broken cirrostratus
Temperature: 72F; Dew Point: 69F; Wind: estimated NE at 3 kts,
Wind Speed and Direction: Light and Variable
Sea-level pressure: 29.90 ins. Hg, rising, then more slowly 
Visibility: 20 miles, obscured by rain showers and thin fog
6-hr Max temp: 72F
6-hr Min temp: 70F
24-hr precip: Trace
BHO SA 1155 E140 BKN 200 BKN 20 124/72/69/E0503/990/ 
RWB12E25 SHWRS DSNT SSE-WSW FEW STFRA DSNT ESE-S 
THN FG ALQDS WND LGT AND VRB/ 8/756 51012 MANUAL 6000/ 10072 20070 

10 A.M.
Weather: Light rain shower, two layers broken altocumulus,
overcast altostratus, few cumulus distant E-WNW, few altocumulus
lenticularis in all directions
Temperature: 73F; Dew Point 67F; Wind: NE at 12G19 kts, 
Sea-level pressure: 29.91 ins. Hg, rising, then falling but still higher
Visibility: 20 miles, obscured by thin fog and light rain showers
3-hr precip: Trace   
BHO SA 1455 E70 BKN 85 BKN 140 OVC 20RW- 130/73/67/0512G19/991/ 
FEW CU DSNT E-WNW FEW ACSL ALQDS THN FG ALQDS/ 8/12/ 50006 MANUAL 6000/

1 P.M.
Weather: Heavy rain shower, overcast stratus
Temperature: 64F; Dew Point: 63F; Wind: NE at 13G21 kts
Sea-level pressure: 29.89 ins. Hg, falling, then more quickly 
Visibility: 1/2 mile, except 3 miles W-NW, 10 miles NNW-NNE,
obscured by heavy rain, thin fog
6-hr Max: 73F
6-hr Min: 64F
6-hr precip: 0.07 inches
BHO SA 1755 E30 OVC 1/2RW+ 122/64/63/0513G21/989/ VSBY W-NW 3 MI NNW-NNE 
10 MI THN FG ALQDS/ 8/6// 58008 ASOS 60001 MANUAL 60007 10073 20064
 

SUMMARY FOR WEDNESDAY, SEPTEMBER 9, 2015 
  
TEMPERATURE (DEGREES F)
MAX.....92   NORMAL.....74 
MIN.....70   NORMAL.....57 
MEAN....81   NORMAL.....66 
 
DEPARTURE FROM 30-YEAR NORMAL.......................+15
TOTAL DEPARTURE FOR THE MONTH.......................+70  [+7.6 DEGREES/DAY]
 
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY..............16   DEPARTURE.........+13
TOTAL COOLING UNITS FOR THE MONTH..............87   DEPARTURE.........+57
TOTAL COOLING UNITS FOR THE SEASON............753   DEPARTURE........+186
TOTAL COOLING UNITS LAST SEASON TO DATE.......561   DIFFERENCE.......+192
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY...................30 SSW AT  5:01 P.M.  
                   ASOS........................32   S AT  5:00 P.M.  
                   DAVIS.......................31 SSW AT  5:00 P.M. RMY 33
FASTEST MILE FOR YESTERDAY.....................25 SSW AT  5:01 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE..................24   S AT  5:23 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................23 SSW AT  5:01 P.M.  
AVERAGE WIND SPEED AND DIRECTION..............14.1 SW  
                   ASOS.......................14.1 
                   DAVIS......................13.2 SW [221 DEG] 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....Trace  DEPARTURE.....-0.13
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE MONTH..........Trace  DEPARTURE.....-1.09
                         ASOS...............0.00
TOTAL PRECIPITATION FOR THE YEAR...........30.26  DEPARTURE.....-5.85
                         ASOS................N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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


9/1  81/65/73/+5/0.00/.../..               20 SSW RMY 20
9/2  89/64/77/+9/0.00/.../..               20 SW  RMY 21  
9/3  85/66/76/+9/T/.../..                  17 E   RMY N/A TSTM 
9/4  72/58/65/0/0.00/.../..                31 ENE RMY N/A
9/5  77/55/66/-1/0.00/.../..               14 SW  RMY 18
9/6  87/57/72/+5/0.00/.../..               21 SSW RMY 22
9/7  92/63/78/+12/0.00/.../..              23 WSW RMY 24
9/8  97/70/84/+18/0.00/.../..              22 WSW RMY 24
9/9  92/70/81/+15/0.00/.../..              30 SSW RMY 33

9/10  low since midnight is 70F; normal low is now 57F  

DAILY RECORDS FOR SEPTEMBER 2015

**9/7 DAILY RECORD MAXIMUM TEMPERATURE OF 92F 
TIES PREVIOUS RECORD SET IN 2007**

**9/8 DAILY RECORD MAXIMUM TEMPERATURE OF 97F
BREAKS PREVIOUS RECORD OF 93F SET IN 2007**

**9/8 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F
BREAKS PREVIOUS RECORD OF 69F SET IN 1999**

**9/9 DAILY RECORD MAXIMUM TEMPERATURE OF 92F
BREAKS PREVIOUS RECORD OF 91F SET IN 2002**

**9/9 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F
BREAKS PREVIOUS RECORD OF 69F SET IN 1999**

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

RECORDS FOR SEPTEMBER 10
HIGH 90F IN 1931,1989
LOW 41F IN 1956
PRECIP 5.60 INCHES IN 1999 (DAILY RECORD FOR SEPTEMBER)
PEAK GUST 48 MPH NW IN 1972

RECORDS FOR SEPTEMBER 11
HIGH 93F IN 1983, 2013
LOW 37F IN 1917
PRECIP 5.23 INCHES IN 1954 (HURRICANE EDNA)
PEAK GUST 101 MPH NW IN 1954 (HURRICANE EDNA)

TODAY'S REPORT PREPARED BY: Brian Fitzgerald