Thursday, September 21, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, SEPTEMBER 21, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

TROPICAL STORM JOSE BRINGS STRONG WINDS TO BLUE HILL

Winds coming from the NNE have been strong and
consistent today. So far today we have had a peak
gust of 47 MPH by 1:00 PM EST. Although today’s
winds are strong it will not match our record daily
peak wind gust of 186 MPH set back in 1938. This is
our highest wind gust of any day on record.

An afternoon storm yesterday brought 0.31 inches
of precip. Today has been dry with humidity lowering
throughout the day but a distant fog lingered keeping
visibility at 30-40 miles.

Today’s Observations:

7 A.M.
Weather: Overcast Stratus
Temperature: 65F; Dew Point: 61F; Wind: NNE at 20G34 kts,
Peak wind: 34 kts (39 MPH) NNE at 6:54 AM EST
Sea-level pressure: 29.98 ins. Hg, rising unsteadily
Visibility: 40 miles
6-hr Max temp: 69F
6-hr Min temp: 65F
24-hr Precip:  0.31 in.
BHO SA 1155 E15 OVC 40 153/65/61/0220G34/998/ DSNT FG ALQDS
PK WND 0234/54/ 8/6// 53024 MANUAL 70031 ASOS 70032 10069 20065

10 A.M.
Weather: Few cumulus SSE-NW, scattered altocumulus,
overcast cirrostratus
Temperature: 66F; Dew Point: 56F; Wind: NNE at 19G35 kts,
Peak wind: 35 kts (40 MPH) NNE at 9:39AM EST
Sea-level pressure: 30.03 ins. Hg, rising, then more quickly
Visibility: 30 miles
BHO SA 1455 200 SCT 250 OVC 30 168/66/56/0219G35/003/ FEW CU SSE-NW
DSNT FG ALQDS PK WND 0236/39/ 8/156 53015

1 P.M.
Weather: Scattered altocumulus, broken cirrostratus
Temperature: 66F; Dew Point: 48F; Wind: NNE at 20G35 kts,
Peak wind: 41 kts (47 MPH) NNE at 12:44 PM EST
Sea-level pressure: 30.01 ins. Hg, rising then falling
Visibility: 40 miles
6-hr Max temp: 68F
6-hr Min temp: 65F
BHO SA 1755 140 SCT E200 BKN 40 164/66/48/0220G35/001/ DSNT FG ALQDS
PK WND 0241/44/ 58004 10068 20065

SUMMARY FOR WEDNESDAY, SEPTEMBER 20, 2017

TEMPERATURE (DEGREES F)
MAX…..68   NORMAL…..70
MIN…..62   NORMAL…..53
MEAN….65   NORMAL…..62

DEPARTURE FROM 30-YEAR NORMAL…………………….+3
TOTAL DEPARTURE FOR THE MONTH……………………+23 [+0.7 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-1
TOTAL COOLING UNITS FOR THE MONTH…………..58   DEPARTURE……….+7
TOTAL COOLING UNITS FOR THE SEASON…………665   DEPARTURE………+77
TOTAL COOLING UNITS LAST SEASON TO DATE…….876   DEPARTURE……..-211

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….-5
TOTAL HEATING UNITS FOR THE MONTH…………..34   DEPARTURE………-18
TOTAL HEATING UNITS FOR THE SEASON………….60   DEPARTURE………-17
TOTAL HEATING UNITS LAST SEASON TO DATE……..17   DEPARTURE………+43

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….41 NNE AT  3:44 P.M.
AERO……………………44 NNE AT  3:42 P.M.
ASOS……………………43 NNE AT  3:44 P.M.
DAVIS…………………..37 NNE AT 11:14 P.M. RMY 45
FASTEST MILE FOR YESTERDAY…………………27 NNE AT  3:43 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………25 NNE AT  3:44 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..25 NNE AT 10:55 P.M.
AVERAGE WIND SPEED AND DIRECTION………….18.0 NNE
ASOS………………….18.0
DAVIS…………………15.6 NNE [018 DEG.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.31  DEPARTURE……+0.17
ASOS…………..0.32
TOTAL PRECIPITATION FOR THE MONTH……….2.39  DEPARTURE……-0.19
ASOS…………..2.43
TOTAL PRECIPITATION FOR THE YEAR……….38.75  DEPARTURE……+1.15
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 TSTM
9/7  74/58/66/0/0.79/417/54                24*WSW AERO 23 WSW RMY 24
9/8  74/53/64/-2/0.00/577/75               21 WSW AERO 18 WSW RMY 22
9/9  68/51/60/-5/T/620/81                  18 ENE AERO 16 ENE RMY 18
9/10 71/51/61/-4/0.00/694/91               18 NW  AERO 16 NW  RMY N/A
9/11 78/50/64/-1/0.00/692/91               20 NNW AERO 17 NNW RMY 20
9/12 84/58/71/+6/0.00/690/91               22 WSW AERO 18 WSW RMY 23
9/13 84/59/72/+8/T/680/90                  18 WSW AERO 15 WSW RMY 20 TSTM
9/14 82/66/74/+10/0.00/233/31              23 SW  AERO 23 WSW RMY 25 TSTM
9/15 83/66/75/+11/0.05/300/40              18 WNW AERO 15 WNW RMY 18
9/16 78/65/72/+9/T/…/..                  14 E   AERO  9 E   RMY 12
9/17 79/61/70/+7/T/…/..                  15 SSE AERO 14 SSE RMY 15
9/18 67/62/65/+3/…./…/..               21 NE  AERO 18 NE  RMY N/A
9/19 63/61/62/0/…./…/..                28 NE* AERO 25 NNE RMY N/A
9/20 68/62/65/+3/…/../..                 41 NNE AERO 44 NNE RMY 45

9/21 Low temp since midnight is 65F; normal low is now 53F

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 21
HIGH 91 IN 1895
LOW 35 IN 1929, 1956, 1962
PRECIP 5.58 INS IN 1961 (HURRICANE ESTHER; RETURNED AS TS SEPT 25-26TH)
PEAK GUST 186 MPH S IN 1938 (GREAT NEW ENGLAND HURRICANE;
CALCULATED GUST, STATION RECORD)

RECORDS FOR SEPTEMBER 22
HIGH 90F IN 1895, 1914
LOW 30F IN 1904 (Earliest freeze)
PRECIP 1.16 INCHES IN 2001
PEAK GUST 60 MPH SSW IN 1989

TODAY’S REPORT PREPARED BY: Kaitlin Geagan