Thursday, September 14, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, SEPTEMBER 14, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

OVERNIGHT THUNDERSTORM LEAVES TRACE OF PRECIPITATION

A quick shower and thunderstorm moved over Great Blue
Hill overnight around 8:00 PM EST leaving only a trace
of precipitation. Temperatures continue to be above
normal with a max. temp. yesterday of 84F which made
the day the second in a row 6F above normal.

Light haze appeared yesterday afternoon and lingered
today reducing visibility to 30 miles during each
observation. The dew point has been steady all day
between 64-65F. This has made for a lower relative
humidity but the air has remained sticky feeling
throughout the day.

Today’s Observations:

7 A.M.
Weather: Broken altocumulus, broken cirrostratus, few
distant cumulus in all directions
Temperature: 69F; Dew Point: 65F; Wind: SW at 10 kts
Sea-level pressure: 29.89 ins. Hg, rising, then more slowly
Visibility: 30 miles except NNE-SSE 50 miles distant fog
SSE-NNE
6-hr Max temp: 69F
6-hr Min temp: 66F
24-hr Precip:  Trace
BHO SA 1155 E120 BKN E250 BKN 30 121/69/65/2310/989/
FEW DSNT CU E AND SSW-W VSBY NNE-SSE 50 DSNT FG SSE-NNE/
8/136 51013 10069 20066

10 A.M.
Weather: Scattered altocumulus, thin broken cirrus, cirrocumulus
overhead, few distant cumulus in all directions
Temperature: 77F; Dew Point: 65F; Wind: SW at 11G17 kts
Sea-level pressure: 29.90 ins. Hg, rising then falling
Visibility: 30 miles, distant haze in all directions
BHO SA 1455 140 SCT E200 -BKN 30 126/77/65/2311G17/990/ FEW
DSNT CU ALQDS CC OVHD DSNT HZ ALQDS/ 8/139 50005

1 P.M.
Weather: Broken cumulus, broken altocumulus, broken
cirrostratus
Temperature: 77F; Dew Point: 64F; Wind: SW at 12G17 kts
Sea-level pressure: 29.88 ins. Hg, falling, then more slowly
Visibility: 30 miles, distant haze in all directions
6-hr Max temp: 80F
6-hr Min temp: 69F
BHO SA 1755 E45 BKN E140 BKN E200 BKN 30 119/77/64/2312G17/988/
DSNT HZ ALQDS/ 8/138 56007 10080 20069

SUMMARY FOR WEDNESDAY, SEPTEMBER 13, 2017

TEMPERATURE (DEGREES F)
MAX…..84   NORMAL…..73
MIN…..59   NORMAL…..56
MEAN….72   NORMAL…..64

DEPARTURE FROM 30-YEAR NORMAL…………………….+8
TOTAL DEPARTURE FOR THE MONTH……………………-20 [-1.7 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………7   DEPARTURE……….+5
TOTAL COOLING UNITS FOR THE MONTH…………..27   DEPARTURE………-12
TOTAL COOLING UNITS FOR THE SEASON…………634   DEPARTURE………+58
TOTAL COOLING UNITS LAST SEASON TO DATE…….847   DEPARTURE……..-213

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….-3
TOTAL HEATING UNITS FOR THE MONTH…………..31   DEPARTURE……….+6
TOTAL HEATING UNITS FOR THE SEASON………….57   DEPARTURE……….+7
TOTAL HEATING UNITS LAST SEASON TO DATE……..11   DEPARTURE………+46

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….18 WSW AT  8:21 P.M.
AERO……………………15 WSW AT  8:20 P.M.
ASOS……………………18 SW  AT  8:21 P.M.
DAVIS………………….N/A                  RMY 20
FASTEST MILE FOR YESTERDAY…………………13 WSW AT  8:21 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………14 SW  AT  8:29 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..13  W  AT 12:01 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..8.5 WSW
ASOS…………………..9.1
DAVIS………………….N/A  W [263 DEG.] 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……….1.52  DEPARTURE……-0.09
ASOS…………..1.55
TOTAL PRECIPITATION FOR THE YEAR……….37.88  DEPARTURE……+1.25
ASOS……………N/A ***
*** ASOS annual total not available due to erroneous readings

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
M:    Missing data

9/1  68/47/58/-10/0.00/749/95              26 WNW AERO 28 WNW RMY 31
9/2  72/46/59/-9/0.00/542/69               18 NNW AERO 18 NNW RMY 21
9/3  63/52/58/-9/0.24/000/00               33 W   AERO 33 W   RMY 37
9/4  79/55/67/0/0.00/702/90                29 SSW AERO 28 SSW RMY N/A
9/5  84/62/73/+6/0.00/583/75               36 S   AERO 32 S   RMY 38
9/6  76/59/68/+1/0.49/070/09               28 S   AERO 28 S   RMY 30
9/7  74/58/66/0/0.79/…/..                24*WSW AERO 23 WSW RMY 24
9/8  74/53/64/-2/T/…/..                  21 WSW AERO 18 WSW RMY 22
9/9  68/51/60/-5/T/…/..                  18 ENE AERO 16 ENE RMY 18
9/10 71/51/61/-4/0.00/…/..               18 NW  AERO 16 NW  RMY N/A
9/11 77/50/64/-1/0.00/…/..               20 NNW AERO 17 NNW RMY 20
9/12 84/58/71/+6/0.00/…/..               22 WSW AERO 18 WSW RMY 23
9/13 84/59/72/+7/…./…/..               18 WSW AERO 15 WSW RMY 20

9/14 Low temp since midnight is 66F; normal low is now 56F

DAILY RECORDS FOR SEPTEMBER

9/1/17: DAILY RECORD LOW MINIMUM TEMPERATURE OF 47F,
TIES PREVIOUS RECORD SET IN 1975

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

RECORDS FOR SEPTEMBER 14
HIGH 90F IN 1931
LOW 34F IN 1911
PRECIP 4.38 INCHES IN 1944 (Great Atlantic Hurricane in 1944)
PEAK GUST 96e MPH E IN 1944 (Great Atlantic Hurricane in 1944)

RECORDS FOR SEPTEMBER 15
HIGH 89F IN 1931
LOW 35F IN 1913
PRECIP 3.93 INCHES IN 1904 (Extra-tropical storm making landfall
in New England on 9/15/1904 passing east of BHO and bringing a
storm total of 4.11 inches 9/14-15/1904)
PEAK GUST 65e MPH NW, WSW IN 1944
(In the wake of Great Atlantic Hurricane)

TODAY’S REPORT PREPARED BY: Kaitlin Geagan