Tuesday, September 6, 2016

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, SEPTEMBER 6, 2016
ALL TIMES ARE IN EASTERN STANDARD TIME

POST TROPICAL STORM HERMINE BRINGS A RATHER UNEXPECTEDLY
HEAVY AMOUNT OF RAINFALL–ONE INCH TO THE SUMMIT
WIND GUSTS PEAK AT 42 NNE EARLY MONDAY EVENING

There was really a lot more rain overnight than we thought
possible out of post-Tropical Storm overnight into early this
morning. A measurement of 0.95 inches in the standard 8-inch
rain gauge was made at 8 A.M. EDT this morning. There was a
half inch by midnight EST late last night and almost an equal
amount during the next 8 hours although the greatest hourly
amount during the whole period as just 0.15 inches last evening!
There were no downpours but just a persistent steady light
rain where only 2 hours out of 15 hours had 0.10 and 0.15 in!
Part of the rainfall was likely the result of orographic
lifting of the very moist air over the hills.

Winds from the NNE-NE peaked at 42 MPH at about 7 P.M. EDT last
evening while the fastest 2-minute wind blew 28 MPH from the
NNE early Labor Day afternoon during a time when we had partial
sunshine through only some high clouds.

Hermine was a tropical cyclone with four names as it first moved
into the Gulf of Mexico from the Caribbean as tropical depression
number nine. It then became a tropical storm and finally Hurricane
(category 1) as it approached northwest Florida from the Gulf. It
then weakened to a tropical storm in Georgia and the Carolinas
before entering the Atlantic off of the North Carolina coast. After
losing its tropical characteristics east of Virginia and Maryland
it became known as post-Tropical Storm Hermine while moving quite
slowly through the ocean well east of the Middle Atlantic states.

Wind gusts to 50 to 60 MPH were recorded across the Cape and Islands
as rain bands swept in from the east. The precipitation then became
more generalized rain and heavy drizzle over eastern Massachusetts
last night and continuing into early this morning. Amounts were generally
up to a half inch (only 0.19 inches at Boston) with the exception of our
unusually heavy rainfall of almost an inch on the summit of Blue Hill.
Even nearby Norwood Airport (3 miles SW) had only 0.57 inches.

PRELIMINARY STATS FOR AUGUST 2016

TEMPERATURE, Deg. F
Avg. Max. 85.1 [+5.9] Avg. Min. 65.0 [+3.2] Mean      75.1 [+4.6] 24-hour corrected mean: 74.1
Max. for month: 95F on 12th
Min. for month: 54F on 23rd

HEATING DEGREE DAYS
Total heating units: 0 [-16] Total for the season: 10 [-15] Total for last season: 1

COOLING DEGREE DAYS
Total cooling units: 318 [+132] Total for the season: 792 [+255] Total for last season: 666

PRECIPITATION, Inches
Total: 1.78 [-2.25] Greatest in 24 hrs: 0.55 in. on 13th and 14th

WIND, mph
Avg. uncorrected wind speed: 10.3
Avg. corrected wind speed: 10.8
Prevailing wind direction: SSW at 14%
Peak gust and direction: 40 SSW on 14th

SUNSHINE:
Campbell-Stokes card minutes: 17460 mins. of possible 24780 or 70%
Astronomical total minutes: 18130 mins. of possible 25714 or 71%

The 24-hour corrected mean temperature for August of 74.1 deg F breaks
the previous record of 72.6 deg F set in 2012 for the warmest August.
August 2016 was 1.5 deg F warmer than the second warmest August on record
while previous records were all within 0.1-0.2 deg F of each other. The
average maximum and minimum temperatures for August 2016 are also new records.
The previous high average max was 83.2 deg F set in August 2005; the previous
high average min was 64.9 deg F set in August 2001.

Summer 2016 was also the warmest summer on record with an average temperature
of 71.6 deg F.  This breaks the previous record of 71.3 deg F set in 2012.
Even with the extreme drought in the Boston area, summer 2016 only ranks as
third driest.

BHO Warmest Augusts, deg F (1885-2016):

1) 74.1 in 2016
2) 72.6 in 2012
3) 72.5 in 1988
4) 72.4 in 2015
5) 72.3 in 2005
6) 72.1 in 2002

BHO Warmest Summers (Jun-Aug), deg F (1885-2016):

1) 71.6 in 2016
2) 71.3 in 2010
3) 70.8 in 1949
4) 70.6 in 1999
5) 70.4 in 1952
6) 70.2 in 2005

BHO Driest Summers (Jun-Aug), inches (1885-2016):

1) 3.48 in 1949
2) 3.54 in 1957
3) 4.90 in 2016
4) 5.24 in 1965
5) 5.43 in 1964
6) 5.45 in 1997

7 A.M.
Weather: Obscurement with heavy fog, light rain and heavy drizzle
Temperature: 62F; Dew Point: 62F; Wind: NNE at 10 kts
Sea-level pressure: 30.06 ins. Hg, rising
Visibility: 1/16 mile in fog, light rain and heavy drizzle
6-hr Max temp: 62F
6-hr Min temp: 62F
24 HR-PRECIP: 0.95 inch
BHO SA 1155 W2X 1/16R-L+F 181/62/62/0210/006/ R- INTMT L+
OCNL L WND GST 22 KTS PST HR/ 8//// 51021 ASOS 60040
MANUAL 6XXX/ ASOS 70094 MANUAL 70095 10062 20062

10 A.M.
Weather: Obscured dense fog
Temperature: 65F; Dew Point: 65F; Wind: NE at 13G20 kts,
Sea-level pressure: 30.11 ins. Hg, about steady
Visibility: 1/16 variable zero mile
3-hr. precip: 0.09
BHO SA 1455 W1X 1/16VF 195/65/65/0513G20/011/ VSBY 1/16V0
WND 36V08 LEXX/ 8//// 51006 MANUAL 6009/

1 P.M.
Weather: Obscured in fog, light drizzle (very light)
Temperature: 66F; Dew Point: 66F; Wind: NE at 12 kts,
Sea-level pressure: 30.11 ins. Hg, about steady
Visibility: 1/8 mile, fog, very light drizzle
6 hr: Max. temp. 67F
6 HR: Min. temp. 62F
6 hr  Precip: 0.11 in.
BHO SA 1755 W3X 1/8L-F 194/66/66/0512/011/ FG DRFTG OVR SMT
LB45 PCPN VRY LGT/ 8//// 58001 MANUAL 6011/ ASOS 60012
10067 20062

SUMMARY FOR MONDAY, SEPTEMBER 5, 2016 – LABOR DAY

TEMPERATURE (DEGREES F)
MAX…..73   NORMAL…..75
MIN…..57   NORMAL…..56
MEAN….65   NORMAL…..67

DEPARTURE FROM 30-YEAR NORMAL……………………-2
TOTAL DEPARTURE FOR THE MONTH……………………-7 [-1.6 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-3
TOTAL COOLING UNITS FOR THE MONTH……………5   DEPARTURE………-13
TOTAL COOLING UNITS FOR THE SEASON…………797   DEPARTURE……..+242
TOTAL COOLING UNITS LAST SEASON TO DATE…….698   DIFFERENCE……..+99

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….-2
TOTAL HEATING UNITS FOR THE MONTH……………0   DEPARTURE……….-7
TOTAL HEATING UNITS FOR THE SEASON………….10   DEPARTURE………-22
TOTAL HEATING UNITS LAST SEASON TO DATE………1   DIFFERENCE………+9

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….42 NNE AT  6:00 P.M. *
AEROVANE………………..33 NNE AT  6:00 P.M.
ASOS……………………43 NNE AT  5:57 P.M.
DAVIS…………………..40 NNE AT  5:56 P.M. RMY 43
FASTEST MILE FOR YESTERDAY…………………27 MME AT  1:31 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………28 NE  AT  1:31 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..26 NNE AT  1:31 P.M.
AVERAGE WIND SPEED AND DIRECTION………….17.2 N
ASOS………………….16.9
DAVIS…………………15.0 NNE [020 Deg.] * Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.95  DEPARTURE……+0.83
ASOS…………..0.94
TOTAL PRECIPITATION FOR THE MONTH……….1.04  DEPARTURE……+0.46
ASOS…………..1.04
TOTAL PRECIPITATION FOR THE YEAR……….26.01  DEPARTURE….. -9.59
ASOS………….26.31

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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

9/1  72/64/68/0/0.09/…/..                  21 NNW AERO 16 NNW RMY 20
9/2  76/58/67/-1/0.00/…/..                 23 ENE AERO 17 NE  RMY 23
9/3 *72/57/65/-2/0.00/…/..                 16 E   AERO 12 E   RMY N/A
9/4  71/58/65/-2/0.00/…/..                 28 NE  AERO 21 NE  RMY 27
9/5  73/57/65/-3/…./..                     42 NNE AER0 33 NNE RMY 43

* there was an error in the computation of the mean temp. for 9/3;
the mean of 72/57 has been corrected to 65 from 64 and a correction
has been made to the departure from normal from -3 to -2. Other parts
of this discussion have been corrected to reflect this change.

9/6  Low temp since midnight is 61F; normal low is now 58F

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

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)

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

TODAY’S REPORT PREPARED BY: Robert Skilling