Sunday, October 4, 2015

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, OCTOBER 4, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME

CHILLY START TO OCTOBER WITH CONTINUED GUSTY NORTHEAST WINDS

The first three days of the month have averaged close to
6 degrees cooler than normal coming after the warmest September.

The light rain and drizzle ended around late morning on Saturday
but a chill northeast wind continues in what now could be called
“a dry nor’easter”.  Winds averaged near 20 MPH all day Saturday
averaging from the east-northeast direction. Gusts reached near
40 MPH.  Again today northeast to east-northeast winds are quite
gusty averaging near 18 MPH with gusts of 25 to 35 MPH. Mostly
cloudy skies continue with temperatures rising only from 50
to 55 degrees by early afternoon.

September 2015 was the warmest September on record here at Blue
Hill Observatory. It also featured the slowest mean wind speed
on record for September, the warmest September average maximum
temperature and second warmest average minimum temperature.
August-September combined was also the warmest on record.
September was the fifth sunniest on record with 70 percent of
the possible bright sunshine, and August-September combined
was the sunniest on record with 72 percent sunshine for those
two months.

Details below:

BHO Warmest Septembers (NWS mean), deg F (1885-2015):

1) 68.2 in 2015
2) 66.9 in 1961
3) 66.5 in 1930
4) 66.4 in 1999
5) 66.2 in 2002
66.2 in 2005

BHO Warmest September Average Maximum Temperature, deg F (1885-2015):

1) 77.8 in 2015
2) 76.6 in 1930
3) 75.7 in 2007
4) 75.6 in 1959
5) 75.5 in 1961

BHO Warmest September Average Minimum Temperature, deg F (1885-2015):

1) 58.8 in 1988
2) 58.5 in 2015
3) 58.2 in 1961
58.2 in 1999
5) 57.8 in 2005

BHO Warmest Aug-Sep (24-hour adjusted mean), deg F (1885-2015):

1) 69.8 in 2015
2) 68.9 in 2005
3) 68.6 in 2002
4) 68.2 in 2010
5) 67.8 in 1959

BHO Slowest September Mean Wind Speed, mph (1885-2015):

1) 10.3 in 2015
2) 10.5 in 2014
3) 10.6 in 2013
4) 10.7 in 2011
5) 10.9 in 1917
10.9 in 2003

BHO Sunniest Septembers, hours (1885-2015):

1) 267.7 in 1983  [74%] 2) 266.9 in 1941  [74%] 3) 265.9 in 2007  [74%] 4) 255.3 in 1948  [71%] 5) 251.9 in 2015  [70%] 6) 251.0 in 1967  [70%] 7) 246.8 in 1952  [69%] 246.8 in 1978  [69%]

BHO Sunniest Aug-Sep, hours (1885-2015):

1) 555.1 in 2015  [72%] 2) 553.0 in 1941  [72%] 3) 536.0 in 2007  [69%] 4) 527.3 in 2014  [68%] 5) 520.2 in 1932  [67%] 6) 515.3 in 1921  [67%] 7) 514.3 in 1968  [67%]

PRELIMINARY STATS FOR SEPTEMBER 2015

TEMPERATURE, Deg. F
Avg. Max. 77.8 [+6.2] Avg. Min. 58.5 [+3.9] Mean      68.2 [+5.1] Corrected mean: 67.3
Max. for month: 97 on 8th
Min. for month: 46 on 27th

COOLING DEGREE DAYS
Total cooling units: 144 [+84] Total for the season: 810 [+213] Total for last season: 587

HEATING DEGREE DAYS
Total heating units: 42 [-75] Total for the season: 43 [-99] Total for last season: 101

PRECIPITATION, Inches
Total: 3.88 [-0.18] Greatest in 24 hrs: 2.53 inches from 9/29-30

WIND, mph
Avg. uncorrected wind speed: 10.1
Avg. corrected wind speed: 10.3
Prevailing wind direction: SSW @ 13%
Peak gust and direction: 47 S on the 30th

SUNSHINE:
Campbell-Stokes card minutes: 15114 mins. of possible 21582 or 70%
Astronomical total minutes:   15766 mins. of possible 22472 or 70%

Today’s Observations:

7 A.M.
Weather: Broken stratocumulus
Temperature: 50F; Dew Point: 41F; Wind: ENE at 15G25 kts,
Sea-level pressure: 30.43 ins. Hg, pressure rising slightly
Visibility: 35 miles, except 50 miles WNW
6-hr Max temp: 50F
6-hr Min temp: 49F
24-hr precip: 0.15 inches
BHO SA 1155 E32 BKN 35 303/50/41/0615G25/043/ VSBY WNW 50
LGT HZ ALQDS/ 8/500 53003 MANUAL 70015 ASOS 70015 10050 20049

10 A.M.
Weather: Scattered stratocumulus, overcast variable broken
stratocumulus
Temperature: 53F; Dew Point 43F; Wind: NE at 15G27 kts,
Peak Wind: 28 knots NE at 9:25 AM EST
Sea-level pressure: 30.42 ins. Hg, falling slightly
Visibility: 30 miles, except 45 miles WNW, light haze
BHO SA 1455 22 SCT E28 OVC 30 300/53/43/0415G27/042/
28 OVC V BKN LGT HZ ALQDS PK WND 0528/25/ 8/500 56003

1 P.M.
Weather: Broken/overcast stratocumulus, bright spots and
breaks in overcast
Temperature: 51F; Dew Point: 43F; Wind: NE at 15G25 kts
Peak Wind: 29 knots NE at 12:39 P.M. EST
Sea-level pressure: 30.38 ins. Hg, decreasing then more rapidly
Visibility: 30 miles, WNW 45, NE-SE 20 hazy
6-hr Max: 55F
6-hr Min: 50F
BHO SA 1755 E22 BKN 31 OVC 30 289/51/43/0515G25/038/
CIG RGD BRGHT SPTS AND BINOVC VSBY WNW 45 NE-SE 20 HAZY ALQDS
PK WND 0529/39/ 8/500 58011 10055 20050

SUMMARY FOR SATURDAY, OCTOBER 3, 2015

TEMPERATURE (DEGREES F)
MAX…..51   NORMAL…..65
MIN…..45   NORMAL…..48
MEAN….48   NORMAL…..56

DEPARTURE FROM 30-YEAR NORMAL……………………-8
TOTAL DEPARTURE FOR THE MONTH…………………..-20  [-6.5 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE………..0
TOTAL COOLING UNITS FOR THE MONTH……………0   DEPARTURE……….-1
TOTAL COOLING UNITS FOR THE SEASON…………810   DEPARTURE……..+212
TOTAL COOLING UNITS LAST SEASON TO DATE…….587   DIFFERENCE…….+223

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..17   DEPARTURE……….+8
TOTAL HEATING UNITS FOR THE MONTH…………..45   DEPARTURE………+19
TOTAL HEATING UNITS FOR THE SEASON………….88   DEPARTURE………-81
TOTAL HEATING UNITS LAST SEASON TO DATE…….139   DIFFERENCE……..-51

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….38  NE  AT  3:38 P.M.
ASOS……………………41  NE  AT  3:43 P.M.
DAVIS…………………..39  ENE AT  2:41 P.M. RMY 40
FASTEST MILE FOR YESTERDAY……………….. 25  ENE AT 11:12 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………25  ENE AT 11:12 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..n/a.
AVERAGE WIND SPEED AND DIRECTION………….19.5 ENE
ASOS………………….18.1
DAVIS…………………16.8 ENE [060 DEG]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…..0.15  DEPARTURE…..+0.01
ASOS……………0.15
TOTAL PRECIPITATION FOR THE MONTH………..0.52  DEPARTURE…..+0.07
ASOS……………0.50
TOTAL PRECIPITATION FOR THE YEAR………..34.19  DEPARTURE…..-4.87
ASOS…………….N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER & OCTOBER 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/+5/0.00/766/97               20 SSW RMY 20
9/2  89/64/77/+9/0.00/732/93               20 SW  RMY 21
9/3  85/66/76/+9/T/612/78                  17 E   RMY N/A TSTM
9/4  72/58/65/-2/0.00/297/38               31 ENE RMY N/A
9/5  77/55/66/-1/0.00/748/96               14 SW  RMY 18
9/6  87/57/72/+5/0.00/753/97               21 SSW RMY 22
9/7  92/63/78/+12/0.00/727/94              23 WSW RMY 24
9/8  97/70/84/+18/0.00/693/90              22 WSW RMY 24
9/9  92/70/81/+15/0.00/683/89              30 SSW RMY 33
9/10 73/62/68/+3/0.32/000/00               29 NE  RMY N/A
9/11 70/59/65/0/0.59/084/11                33 NE  RMY N/A
9/12 75/58/67/2/…./380/50                18 SSE RMY 25
9/13 66/60/63/-1/…./000/00               25 E   RMY N/A
9/14 70/53/62/-2/0.00/550/73               33 W   RMY 35
9/15 82/56/69/+5/0.00/736/98               23 W   RMY N/A
9/16 84/62/73/+10/0.00/711/95              17 NW  RMY N/A
9/17 87/64/76/+13/0.00/723/97              17 SW  RMY 16
9/18 86/64/75/+13/0.00/712/96              21 SSW RMY 21
9/19 80/62/71/+9/0.00/480/65               22 S   RMY N/A
9/20 74/55/65/+3/T/552/75                  24 S   RMY N/A
9/21 65/50/58/-3/0.00/646/88               29 ENE RMY 30
9/22 67/55/61/+0/0.00/183/25               21 E   RMY 21
9/23 72/50/61/+1/0.00/677/93               15 E   RMY N/A
9/24 72/56/64/+4/0.00/696/96               22 E   RMY 21
9/25 66/53/60/0/0.00/556/77                21 E   RMY 20
9/26 63/49/56/-3/0.00/633/88               25 ENE RMY 25
9/27 71/46/59/+0/0.00/688/96               17 S   RMY 18
9/28 81/57/69/+11/0.00/428/60              22 SSW RMY 24
9/29 82/65/74/+16/…./320/45              28 S   RMY N/A
9/30 75/53/64/+6/…./000/00               47 S   RMY 51  TSTM

10/1 55/51/53/-4/…./…/..               39 NE  RMY N/A
10/2 51/47/49/-8/…./…/..               40 NE  RMY 43
10/3 51/45/48/-8/…./000/00               38 NE  RMY 40

10/3 low since midnight is 49F; normal low is now 47F

DAILY RECORDS FOR SEPTEMBER & OCTOBER 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**

**9/17 DAILY RECORD MAXIMUM TEMPERATURE OF 87F
BREAKS PREVIOUS RECORD OF 86F SET IN 1915, 1941, AND 1991**

**9/18 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 64F
TIES PREVIOUS RECORD SET IN 1992**

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

RECORDS FOR OCTOBER 4
HIGH 84F IN 2007
LOW 28F IN 1888
PRECIP 1.87 INCHES IN 2011
PEAK GUST 59 MPH SSW IN 1990

RECORDS FOR OCTOBER 5
HIGH 86F IN 2007
LOW 29F IN 1965
PRECIP 3.17 INCHES IN 1962
PEAK GUST 64e MPH S IN 1979

TODAY’S REPORT PREPARED BY: Robert Skilling