Saturday, September 5, 2015

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, SEPTEMBER 5, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME

SPECTACULAR LATE SUMMER WEATHER TODAY…BRILLIANT SUNSHINE
WITH SEASONABLE TEMPERATURES AND LOW HUMIDITY…AUGUST
SUNSHINE WAS THE SECOND HIGHEST ON RECORD…

The cold front that crossed the area yesterday has brought a
brief return to temperatures that are close to average with
the dew point dropping from the 50’s to the 40’s this
afternoon. The minimum temperature this morning of 55F was
the coolest reading since 50F on June 29th. As of mid-afternoon,
the dew point has reached 40F.

With the dry air, the visibility has been excellent today in
the 75-80 mile range.  Only a few thin cirrus and distant
cumulus over the ocean to the south east have interrupted
a nearly completely clear sky.

Corrections to the preliminary sunshine data for August has
increased the total from the Campbell-Stokes sunshine recorder
to 303.2 hours, which is 73 percent of possible.  This is
the second highest amount of sunshine ever recorded in August.

BHO Warmest Augusts, deg F (1885-2015)

1) 72.6 in 2012
2) 72.5 in 1988
3) 72.4 in 2015
4) 72.3 in 2005
5) 72.1 in 2002

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

1) 83.2 in 2005
2) 83.1 in 1949
3) 82.6 in 2015
4) 82.5 in 1988
82.5 in 2002
82.5 in 2012

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

1) 64.9 in 2001
2) 64.6 in 2012
3) 64.4 in 2005
64.4 in 2015
5) 64.3 in 2003

BHO Slowest August Wind Speed, mph (1885-2015)

1) 9.5 in 1996
9.5 in 2008
3) 10.0 in 1899
10.0 in 2009
10.0 in 2012
10.0 in 2015

BHO Sunniest Augusts, hours (1886-2015)

1) 303.7 in 1971  (74%)
2) 303.2 in 2015  (73%)
3) 303.0 in 1969  (73%)
4) 298.1 in 1932  (72%)
5) 296.7 in 1970  (72%)

PRELIMINARY STATS FOR AUGUST 2015

TEMPERATURE, Deg. F
Avg. Max. 82.6 [+3.4] Avg. Min. 64.4 [+2.6] Mean      73.5 [+3.0] Corrected mean: 72.4
Max. for month: 92 on 18th
Min. for month: 58 on 8th, 10th, 28th

HEATING DEGREE DAYS (JUL-JUN)
Total heating units: 0 [-16] Total for the season: 1 [-24] Total for last season: 2

COOLING DEGREE DAYS (JAN-DEC)
Total cooling units: 272 [+86] Total for the season: 666 [+129] Total for last season: 479

PRECIPITATION, Inches
Total: 2.90 [-1.13] Greatest in 24 hrs: 1.24, 15th-16th

WIND, mph
Avg. uncorrected wind speed: 9.3
Avg. corrected wind speed: 10.0
Prevailing wind direction: WNW @ 15%
Peak gust and direction: 45 W on the 4th [TSTM GUST]

SUNSHINE: (corrected)
Campbell-Stokes card minutes: 18192 mins. of possible 24780 or 73%
Astronomical total minutes:   18916 mins. of possible 25773 or 73%
Long-term average for August is 58%

Today’s Observations:

7 A.M.
Weather: Clear, few cumulus and cumulus fractus distant E-SSE,
few cirrus distant NNW-ESE, thin smoke layer along horizon NW-NE
Temperature: 59F; Dew Point: 54F; Wind: NNE at 8 kts,
Sea-level pressure: 30.33 ins. Hg, rising then more slowly
Visibility:  80 miles
6-hr Max temp: 59F
6-hr Min temp: 55F
24-hr precip: 0.00
BHO SA 1155 CLR 80 270/59/54/0208/033/ FEW CU/CUFRA DSNT E-SSE
FEW CI DSNT NNW-ESE THN K LYR ALG HRZN NW-NE/ 8/101 51017 10059
20055

10 A.M.
Weather: Clear, few cumulus and cumulus fractus distant ESE-SSW,
few cirrus distant NNW-E
Temperature: 71F; Dew Point 50F; Wind: ENE at 7 kts,
Sea-level pressure: 30.32 ins. Hg, falling slightly
Visibility: 80 miles
BHO SA 1455 CLR 80 269/71/50/0707/032/ FEW CU/CUFRA DSNT ESE-SSW
FEW CI DSNT NNW-E/ 8/101 58001

1 P.M.
Weather: Thin scattered cirrus, few cumulus and cumulus fractus
distant ESE-S
Temperature: 76F; Dew Point: 49F; Wind: NE at 7 kts
Sea-level pressure: 30.28 ins. Hg, falling then more slowly
Visibility: 75 miles
BHO SA 1755 250 -SCT 75 253/76/49/0507/028/ FEW CU/CUFRA DSNT
ESE-S/ 8/101 56016 10076 20059

SUMMARY FOR FRIDAY, SEPTEMBER 4, 2015

TEMPERATURE (DEGREES F)
MAX…..72   NORMAL…..76
MIN…..58   NORMAL…..59
MEAN….65   NORMAL…..67

DEPARTURE FROM 30-YEAR NORMAL……………………-2
TOTAL DEPARTURE FOR THE MONTH…………………..+21  [+5.1 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-4
TOTAL COOLING UNITS FOR THE MONTH…………..31   DEPARTURE………+16
TOTAL COOLING UNITS FOR THE SEASON…………697   DEPARTURE……..+145
TOTAL COOLING UNITS LAST SEASON TO DATE…….528   DIFFERENCE…….+169

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….31 ENE AT  6:13 A.M.  *
ASOS……………………33 ENE AT  5:39 A.M.
DAVIS…………………..30 ENE AT  5:38 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY…………………24  NE AT  4:59 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………22  NE AT  5:01 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..21  NE AT  5:00 A.M.
AVERAGE WIND SPEED AND DIRECTION………….11.8 ENE
ASOS………………….11.9
DAVIS…………………10.1 ENE [63 DEG]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…..0.00  DEPARTURE…..-0.12
ASOS……………0.00
TOTAL PRECIPITATION FOR THE MONTH……….Trace  DEPARTURE…..-0.46 [corrected] ASOS……………0.00
TOTAL PRECIPITATION FOR THE YEAR………..30.26  DEPARTURE…..-5.22 [corrected] ASOS…………….N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR AUGUST & 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

8/1  88/68/78/+6/0.06/729/84               28 WNW RMY N/A
8/2  86/62/74/+2/0.00/865/100              24 SW  RMY N/A
8/3  89/68/79/+7/0.00/690/80               31 S   RMY N/A
8/4  86/66/76/+4/0.31/422/49               45 W   RMY 50  TSTM
8/5  84/64/74/+2/0.00/765/89               28 WNW RMY 27
8/6  80/59/70/-2/0.00/685/80               22 W   RMY 21
8/7  78/61/70/-2/0.00/845/99               20 ESE RMY 18
8/8  77/58/68/-4/0.00/741/87               18 E   RMY N/A
8/9  72/59/66/-6/T/458/54                  27 NNE RMY 26
8/10 84/58/71/0/0.00/830/98                28 S   RMY N/A
8/11 70/63/67/-4/0.52/000/00               32 SSE RMY 35
8/12 83/65/74/+3/0.00/766/91               22 W   RMY 20
8/13 83/62/73/+2/0.00/832/99               18 WNW RMY 18
8/14 86/63/75/+4/0.00/837/100              21 S   RMY 23
8/15 91/66/79/+8/1.24/534/64               38 W   RMY 41  TSTM
8/16 87/65/76/+5/T/774/93                  16 W   RMY N/A TSTM
8/17 90/70/80/+9/0.00/805/97               17 W   RMY 18
8/18 92/70/81/+10/0.27/546/66 *            31 W   RMY 32  TSTM
8/19 87/69/78/+8/0.00/775/94               23 S   RMY 24
8/20 85/70/78/+8/0.00/723/88               22 ESE RMY 22
8/21 82/69/76/+6/0.31/328/40  *            21 S   RMY 23
8/22 73/66/70/0/T/98/12                    18 ENE RMY 16
8/23 70/66/68/-2/0.18/000/00               20 ENE RMY 18
8/24 78/67/73/+3/0.01/122/15               18 SSW RMY 19
8/25 85/68/77/+8/0.00/526/65               22 S   RMY 22
8/26 82/64/73/+4/0.00/629/78               21 NW  RMY 22
8/27 79/59/69/0/0.00/779/97                22 W   RMY 23
8/28 80/58/69/0/0.00/753/94                15 NW  RMY 15
8/29 81/60/71/+2/0.00/766/96  *            21 WSW RMY 21
8/30 86/65/76/+8/0.00/588/74               23 W   RMY 23
8/31 87/68/78/+10/0.00/705/89              26 W   RMY 28

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/trace/…/..              17 E   RMY N/A TSTM
9/4  72/58/65/0/0.00/…/..                31 ENE RMY N/A

9/5  low since midnight is 55F; normal low is now 58F

* Sunshine corrected for August 21st and 29th.
* Mean temperature corrected for August 18th and 29th.

DAILY RECORDS FOR AUGUST 2015
None so far.

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

RECORDS FOR SEPTEMBER 5
HIGH 90F IN 1971
LOW 45F IN 1906
PRECIP 1.37 INCHES IN 1907
PEAK GUST 46 MPH NW IN 1994

RECORDS FOR SEPTEMBER 6
HIGH 92F IN 1900
LOW 39F IN 1888
PRECIP 3.19 INCHES IN 1890
PEAK GUST 78e MPH SE IN 1979 (TROPICAL STORM DAVID)

TODAY’S REPORT PREPARED BY: Mike Iacono