BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, JULY 21, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME
 
HEAT WAVE FINALLY ENDS
 
After 6 days of 90+ degree heat, the heat wave has ended today as the
temperature has only climbed to 81F by 2 PM EDT this afternoon, and is
unlikely to rise much further.  The humidity has also come down somewhat
today, giving the air a more pleasant feel than it has had over the past
several days.  Winds have been very light for the most part, with a
persistent eastward component that has kept the air coming in from the
ocean, preventing a major rise in temperature.  The sky has been mostly
cloudy today, with a combination of altocumulus, cirrus, and cumulus that
have been forming and building this afternoon.  No precipitation fell at
the summit yesterday, though thunder and lightning were observed from
thunderstorms that moved to our south. 
 
The recent heat wave lasted six days at the Observatory. A total of 6
records, all highest minimum temperature, were tied or broken.  For three
consecutive days, July 18-20, the temperature at 7 AM EST was 80F or higher.
Although higher temperatures have been recorded at this time of day in
recent years, this may be the first occurrence on record of three straight
days of 80F or higher at that time of day in records checked back about 50
years.  In addition, this month has so far seen 10 days with a high
temperature of 90F or higher, which is among the greatest number of such
days for any month on the entire period of record. 
 
BHO Greatest Number of 90-Degree Days per Month, (1885-2013)
 
1) 14 in July 1952
2) 13 in August 2002
3) 10 in August 1944
   10 in July 1949
   10 in July 1963
   10 in July 2010
   10 in July 2013 (through 7/21)
8)  9 in July 1911
    9 in August 1928
10) 8 in August 1949
    8 in July 1963
    8 in July 1988
 
BHO Longest Heat Waves of Consecutive 90-Degree Days, (1885-2013)
 
1)  9 on 11-19 August 2002
2)  8 on 10-17 August 1944
3)  6 on 24-29 July 1963
    6 on 16-21 July 1977
    6 on  6-11 July 1988
    6 on 16-21 July 1991
    6 on 15-20 July 2013
 
BHO Highest 7AM EST Temperature, deg F (1960-2013)
 
1) 84 on 6 July 2010
2) 83 on 22 July 2011
3) 82 on 21 July 1991
   82 on 18 July 2012
5) 81 on 2 August 1975
   81 on 27 June 1999
   81 on 18 July 2013  *
   81 on 20 July 2013  *
9) 80 on 23 July 1978
   80 on 23 July 1998
   80 on 5 July 1999
   80 on 6 July 1999
   80 on 9 August 2001
   80 on 4 July 2002
   80 on 30 July 2002
   80 on 2 August 2006
   80 on 3 August 2006
   80 on 21 June 2012
   80 on 22 June 2012
   80 on 19 July 2013  *
 
Today's Observations:
 
7 A.M.
Weather: Scattered altocumulus, broken altocumulus, few altocumulus
castellanus E and SSW-SW, rain shower distant SE-SW moving E
Temperature: 73F; Dew Point: 64F; Wind: NNE at 5 kts
Sea-level pressure: 29.94 ins. Hg, rising
Visibility: 50 miles, light distant haze
6-hr min. temp: 69F
BHO SA 1155 75 SCT E95 BKN 250 BKN 50 134/73/64/0305/994/
FEW ACC E AND SSW-SW SHRA DSNT SE-SW MOVG E LGT DSNT HZ 8/081
52017 10073 20069
 
10 A.M.
Weather: Scattered altocumulus stratiformis undulatus, broken dense cirrus,
broken cirrus, few cumulus distant all quadrants except NE, few cirrocumulus
Temperature: 78F; Dew Point: 67F; Wind: NE at 6 kts,
Wind: Direction variable NNE-E
Sea-level pressure: 29.96 ins. Hg, rising then rising more slowly
Visibility: 40 miles, light distant haze
BHO SA 1455 90 SCT E200 BKN 250 BKN 40 144/78/67/0506/996/
FEW CU DSNT ALQDS XCPT NE FEW CC LGT DSNT HZ/ 8/151 51010
 
1 P.M.
Weather: Scattered cumulus, scattered altocumulus, broken dense cirrus,
broken cirrus, few moderate cumulus, few altocumulus lenticularis NW-NNE
Temperature: 80F; Dew Point: 65F; Wind: Estimated ENE at 5 kts,
Wind: Light and variable
Sea-level pressure: 29.96 ins. Hg, rising then falling
Visibility: 40 miles, light distant haze
6-hr max. temp: 81F
BHO SA 1755 30 SCT 95 SCT E200 BKN 250 BKN 40 147/80/65/E0605/996/
FEW MDT CU FEW ACSL NW-NNE LGT DSNT HZ WND LGT AND VRB/ 8/241 50003
10081 20073
 
WEATHER SUMMARY FOR SATURDAY, JULY 20, 2013
 
TEMPERATURE (DEGREES F)
MAX.....93     NORMAL.....81
MIN.....72     NORMAL.....63
MEAN....82     NORMAL.....72
 
DEPARTURE FROM 30-YEAR NORMAL.....................+10
TOTAL DEPARTURE FOR THE MONTH....................+123 [+6.0 DEGREES/DAY]
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY................29 W   AT   1:48 P.M. *
                   AERO.....................30 W   AT   1:36 P.M.
                   ASOS.....................30 SW  AT  12:16 P.M.
                   DAVIS....................29 SW  AT  12:15 P.M.  RMY 31
FASTEST MILE FOR YESTERDAY..................23 WSW AT  12:20 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE...............22 SW  AT  11:44 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..............21 SW  AT  11:44 A.M.
AVERAGE WIND SPEED AND DIRECTION..........11.5 WSW
                   ASOS...................10.4 
                   DAVIS..................10.6 SW [232 deg.]
* last of several occurrences...
 
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..........1.01   DEPARTURE............-1.45
                         ASOS..............1.00
TOTAL PRECIPITATION FOR THE YEAR..........33.21   DEPARTURE............+3.78
                         ASOS..............N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals 
     
PRELIMINARY CLIMATE SUMMARY FOR JULY 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
RMY:  RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
                             
7/1  82/69/76/+6/0.05/247/27         29 S   AERO 31 MPH SSW RMY 32
7/2  82/61/72/+2/T/100/11            23 SSW AERO 23 MPH SSW RMY 25
7/3  87/62/75/+4/T/556/61            28 SW  AERO 30 MPH SW  RMY 30
7/4  90/71/81/+10/0.00/811/89        25 WSW AERO 26 MPH SW  RMY 28
7/5  92/73/83/+12/0.00/874/96        24 W   AERO 25 MPH WSW RMY 25
7/6  90/73/82/+11/0.00/836/92        25 WNW AERO 25 MPH WNW RMY 26
7/7  91/72/82/+11/0.21/508/56        38 SSW AERO 43 MPH SSW RMY 44  TSTM
7/8  82/64/73/+1/0.04/617/68         18 NE  AERO 20 MPH NE  RMY 20  TSTM
7/9  72/63/68/-4/0.01/054/06         14 ENE AERO 14 MPH ENE RMY 14
7/10 84/65/75/+3/T/335/37            32 S   AERO 36 MPH S   RMY 35
7/11 79/69/74/+2/0.62/009/01         23 W   AERO 23 MPH W   RMY N/A TSTM
7/12 70/62/66/-6/0.00/162/18         29 NE  AERO 29 MPH NE  RMY 30
7/13 75/62/69/-3/0.08/009/01         21 ENE AERO 20 MPH ENE RMY N/A
7/14 89/71/80/+8/0.00/477/53         16 W   AERO 16 MPH W   RMY 16
7/15 91/72/82/+10/0.00/665/74        17 NW  AERO 16 MPH NW  RMY 18
7/16 91/71/81/+9/0.00/843/94         18 NNW AERO 16 MPH NNW RMY 16
7/17 93/74/84/+12/0.00/.../..        22 SW  AERO 23 MPH SW  RMY 25
7/18 90/75/83/+11/0.00/.../..        20 S   AERO 21 MPH S   RMY 22
7/19 95/76/86/+14/0.00/.../..        36 WSW AERO 38 MPH WSW RMY 38
7/20 93/72/82/+10/0.00/.../..        29 W   AERO 30 MPH W   RMY 31 TSTM
 
7/21 morning low temp: 69F; the normal low is now 63F
 
DAILY RECORDS FOR JULY 2013
7/14 - TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 71F;
       ties previous record of 71F set in 1997
7/15 - NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 72F;
       surpasses previous record of 70F set in 1901, 1934, 1995
7/16 - TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 71F;
       ties previous record of 71F set in 1901, 1958, 1968
7/17 - TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 74F;
       ties previous record of 74F set in 1900
7/18 - NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 75F;
       surpasses previous record of 73F set in 1900, 1999
7/19 - NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 76F;
       surpasses previous record of 72F set in 1949, 1991, 2005
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR JULY 21
HIGH 100F IN 1977 [RECORD FOR MONTH]
LOW 48F IN 1890
PRECIP 2.09 INCHES IN 1938
PEAK GUST 60e MPH WNW IN 1977
 
RECORDS FOR JULY 22
HIGH 99F IN 1926, 2011
LOW 52F IN 1890
PRECIP 1.73 INCHES IN 1900
PEAK GUST 55 MPH IN 1983
 
TODAY'S REPORT PREPARED BY: Jonathan O'Brien