Tuesday, September 12, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, SEPTEMBER 12, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM AND DRY CONDITIONS PERSIST

It’s another warm day for September.  Temperatures
fell to 58F overnight and rose to 83F by 1:00PM EST
already making the day 6F above normal.  The dry air
has kept dew points in the low 50s for most of the day
and skies mostly sunny with few to scattered cirrus.
Winds were light and variable and out of the west, while
visibility remained at 70 miles.

Today’s Observations:

7 A.M.
Weather: Few cirrus SE-W
Temperature: 63F; Dew Point: 49F; Wind: WNW at 7 kts
Sea-level pressure: 30.03 ins. Hg, rising then falling
Visibility: 70 miles
6-hr Max temp: 63F
6-hr Min temp: 58F
24-hr Precip:  0.00 in.
BHO SA 1155 CLR 70 168/63/49/3007/003/ FEW CI SE-W/
8/001 58005 10063 20058

10 A.M.
Weather: Few cirrus in all directions
Temperature: 75F; Dew Point: 55F; Wind: estimated W at 2 kts,
Wind: Light and variable
Sea-level pressure: 30.00 ins. Hg, steady then falling
Visibility: 70 miles
BHO SA 1455 CLR 70 160/75/55/E2702/000/ FEW CI ALQDS WND L/V/
8/001 58008

1 P.M.
Weather: Scattered cirrus
Temperature: 82F; Dew Point: 51F; Wind: W at 7 kts,
Wind direction: Variable WSW to NW
Sea-level pressure: 29.95 ins. Hg, falling, then more quickly
Visibility: 70 miles
6-hr Max temp: 83F
6-hr Min temp: 63F
BHO SA 1755 250 SCT 70 141/82/51/2707/995/ WND 25V32/
8/001 58019 10083 20063

SUMMARY FOR MONDAY, SEPTEMBER 11, 2017

TEMPERATURE (DEGREES F)
MAX…..77   NORMAL…..74
MIN…..50   NORMAL…..57
MEAN….64   NORMAL…..65

DEPARTURE FROM 30-YEAR NORMAL…………………….-1
TOTAL DEPARTURE FOR THE MONTH……………………-34 [-3.3 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-2
TOTAL COOLING UNITS FOR THE MONTH…………..14   DEPARTURE………-21
TOTAL COOLING UNITS FOR THE SEASON…………621   DEPARTURE………+49
TOTAL COOLING UNITS LAST SEASON TO DATE…….843   DEPARTURE……..-222

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………1   DEPARTURE……….-2
TOTAL HEATING UNITS FOR THE MONTH…………..31   DEPARTURE………+12
TOTAL HEATING UNITS FOR THE SEASON………….57   DEPARTURE………+13
TOTAL HEATING UNITS LAST SEASON TO DATE……..11   DEPARTURE………+46

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….20 NNW AT 4:38 A.M.
AERO……………………17 NNW AT 4:36 A.M.
ASOS……………………20 NNW AT 4:39 A.M.
DAVIS…………………..24 NW  AT 8:13 A.M. RMY 20
FASTEST MILE FOR YESTERDAY…………………14 NNW AT 4:38 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………15 NW  AT 7:53 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..14 NW  AT 7:52 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..9.5 WNW
ASOS…………………..9.8
DAVIS………………….7.5 NW [307 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……+0.17
ASOS…………..1.55
TOTAL PRECIPITATION FOR THE YEAR……….37.88  DEPARTURE……+1.51
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 Low temp since midnight is 58F; 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 12
HIGH 92F IN 1961
LOW 42F IN 1958,1967,1985
PRECIP 2.79 INCHES IN 1960 (HURRICANE DONNA)
PEAK GUST 140 MPH SSE IN 1960 (HURRICANE DONNA)

RECORDS FOR SEPTEMBER 13
HIGH 91F IN 1957
LOW 40F IN 1985
PRECIP 3.10 INCHES IN 1987
PEAK GUST 44 MPH WNW IN 1986

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle