Sunday, September 10, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, SEPTEMBER 10, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

ANOTHER COOL BUT PLEASANT DAY

Yesterday’s afternoon rain showers mostly stayed to
the north and west of the observatory, but a brief
rain shower did fall around 3:00PM EST leaving no
measurable amount of precip.  Scattered showers are
again possible this afternoon as larger cumulus
continue to develop through the day.

Temperatures remain slightly below normal today.  A
minimum of 51F occurred this morning, and the max. by
1:00PM was 70F.  The dry air and mostly sunny skies
have made this early fall day a pleasant one.

Today’s Observations:

7 A.M.
Weather: Few distant cumulus WNW-SE
Temperature: 55F; Dew Point: 50F; Wind: N at 9 kts
Sea-level pressure: 30.32 ins. Hg, rising, then more slowly
Visibility: 70 miles
6-hr Max temp: 55F
6-hr Min temp: 51F
24-hr Precip:  Trace
BHO SA 1155 CLR 70 269/55/50/3509/032/ FEW CU DSNT WNW-SE/
8/100 51016 10055 20051

10 A.M.
Weather: Few cumulus in all directions
Temperature: 65F; Dew Point: 51F; Wind: N at 8 kts
Sea-level pressure: 30.34 ins. Hg, rising then falling
Visibility: 70 miles
BHO SA 1455 CLR 70 275/65/51/3508/034/ FEW CU ALQDS/ 8/100 50006

1 P.M.
Weather: Scattered cumulus, scattered cirrus
Temperature: 70F; Dew Point: 53F; Wind: N at 6 kts,
Wind speed: Light
Sea-level pressure: 30.32 ins. Hg, falling, then more quickly
Visibility: 70 miles
6-hr Max temp: 70F
6-hr Min temp: 55F
BHO SA 1755 34 SCT 250 SCT 70 268/70/53/3506/032/ WND LGT/
8/101 58007 10070 20055
SUMMARY FOR SATURDAY, SEPTEMBER 9, 2017

TEMPERATURE (DEGREES F)
MAX…..68   NORMAL…..74
MIN…..51   NORMAL…..57
MEAN….60   NORMAL…..66

DEPARTURE FROM 30-YEAR NORMAL…………………….-6
TOTAL DEPARTURE FOR THE MONTH……………………-29 [-3.4 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-3
TOTAL COOLING UNITS FOR THE MONTH…………..14   DEPARTURE………-16
TOTAL COOLING UNITS FOR THE SEASON…………621   DEPARTURE………+54
TOTAL COOLING UNITS LAST SEASON TO DATE…….827   DEPARTURE……..-206

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………5   DEPARTURE……….+3
TOTAL HEATING UNITS FOR THE MONTH…………..26   DEPARTURE………+11
TOTAL HEATING UNITS FOR THE SEASON………….52   DEPARTURE………+12
TOTAL HEATING UNITS LAST SEASON TO DATE……..11   DEPARTURE………+41

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….18 ENE AT 10:39 A.M.
AERO……………………16 ENE AT 10:52 A.M.
ASOS……………………19 ENE AT 10:56 A.M.
DAVIS…………………..22  NW AT  4:11 A.M. RMY 18
FASTEST MILE FOR YESTERDAY…………………13  NW AT  1:11 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………14 ENE AT 10:58 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..13 ENE AT 10:56 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..7.9 NNW
ASOS…………………..8.6
DAVIS………………….6.8  N [347 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……+0.43
ASOS…………..1.55
TOTAL PRECIPITATION FOR THE YEAR……….37.88  DEPARTURE……+1.77
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/…/..              26 WNW AERO 28 WNW RMY 31
9/2  72/46/59/-9/0.00/…/..               18 NNW AERO 18 NNW RMY 21
9/3  63/52/58/-9/0.24/…/..               33 W   AERO 33 W   RMY 37
9/4  79/55/67/0/0.00/…/..                29 SSW AERO 28 SSW RMY N/A
9/5  84/62/73/+6/0.00/…/..               36 S   AERO 32 S   RMY 38
9/6  76/59/68/+1/…./…/..               28 S   AERO 28 S   RMY 30
9/7  74/58/66/0/…./…/..                24*WSW AERO 23 WSW RMY 24
9/8  74/53/64/-2/0.00/…/..               21 WSW AERO 18 WSW RMY 22
9/9  68/51/60/-5/T/…/..                  18 ENE AERO 16 ENE RMY 18

9/10 Low temp since midnight is 51F; normal low is now 57F

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 10
HIGH 90F IN 1931,1989
LOW 41F IN 1956
PRECIP 5.60 INCHES IN 1999 (DAILY RECORD FOR SEPTEMBER)
PEAK GUST 48 MPH NW IN 1972

RECORDS FOR SEPTEMBER 11
HIGH 93F IN 1983, 2013
LOW 37F IN 1917
PRECIP 5.23 INCHES IN 1954 (HURRICANE EDNA)
PEAK GUST 101 MPH NW IN 1954 (HURRICANE EDNA)

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle