Monday, September 18, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, SEPTEMBER 18, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

LIGHT DRIZZLE BEGINS BEFORE 10:00AM EST

A trace of precip. was measured at the 1:00PM ob from
light drizzle which began shortly before 10:00AM.  The
mostly cloudy skies in the morning became overcast by
late morning as the drizzle began.  After some clearing
in the morning, fog again returned to Great Blue Hill
and limited visibility to 2-3 miles in the afternoon.

Temperatures have remained fairly constant due to the
overcast skies and fog.  The max. at 1:00PM was 67F
from an overnight low of 63F.  Wind direction became
northeasterly around 7:00AM, while wind speeds have
slightly increased compared to the previous days to
approximately 6-7 miles per hour.

Today’s Observations:

7 A.M.
Weather: Fog N-NE, few stratus fractus ENE-SSE, broken stratocumulus
Temperature: 65F; Dew Point: 63F; Wind: estimated NE at 3 kts,
Wind speed: Light
Sea-level pressure: 30.18 ins. Hg, rising, then more quickly
Visibility: 15 miles, except 5 miles N-NE, distant fog ENE-NNW
6-hr Max temp: 65F
6-hr Min temp: 63F
24-hr Precip:  0.00 in.
BHO SA 1155 E11 BKN 15 221/65/63/E0503/018/ FEW STFRA ENE-SSE
VSBY N-NE 5 FG N-NE DSNT FG ENE-NNW WND LGT/ 8/700 53007 10065
20063

10 A.M.
Weather: Light drizzle, broken stratus, overcast nimbostratus
Temperature: 66F; Dew Point: 63F; Wind: NE at 6 kts,
Wind speed: Light
Sea-level pressure: 30.19 ins. Hg, rising then falling
Visibility: 15 miles, except 10 miles N-ENE, distant fog in all
directions
3-hr Precip: Trace
BHO SA 1455 E8 BKN 18 OVC 15L- 222/66/63/0406/019/ VSBY N-ENE 10
DSNT FG ALQDS PCPN VRY LGT WND LGT/ 8/62/ 50001 MANUAL 600//

1 P.M.
Weather: Light drizzle, sky obscurement due to fog
Temperature: 65F; Dew Point: 65F; Wind: NE at 6 kts,
Wind speed: Light
Sea-level pressure: 30.18 ins. Hg, falling, then more quickly
Visibility: 2 miles, except 3 miles SE
6-hr Max temp: 67F
6-hr Min temp: 65F
6-hr Precip: Trace
BHO SA 1755 W3 X 2L-F 219/65/65/0606/018/ VSBY SE 3 PCPN VRY LGT
WND LGT/ 8//// 58003 MANUAL 600// 10067 20065

SUMMARY FOR SUNDAY, SEPTEMBER 17, 2017

TEMPERATURE (DEGREES F)
MAX…..79   NORMAL…..71
MIN…..61   NORMAL…..55
MEAN….70   NORMAL…..63

DEPARTURE FROM 30-YEAR NORMAL…………………….+7
TOTAL DEPARTURE FOR THE MONTH……………………+17 [+0.8 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………5   DEPARTURE……….+3
TOTAL COOLING UNITS FOR THE MONTH…………..58   DEPARTURE………+12
TOTAL COOLING UNITS FOR THE SEASON…………665   DEPARTURE………+82
TOTAL COOLING UNITS LAST SEASON TO DATE…….856   DEPARTURE……..-191

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….-4
TOTAL HEATING UNITS FOR THE MONTH…………..31   DEPARTURE……….-8
TOTAL HEATING UNITS FOR THE SEASON………….57   DEPARTURE……….-7
TOTAL HEATING UNITS LAST SEASON TO DATE……..17   DEPARTURE………+40

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….15 SSE AT 6:50 P.M.
AERO……………………14 SSE AT 6:44 P.M.
ASOS……………………14 SSE AT 6:50 P.M.
DAVIS…………………..14  S  AT 6:42 P.M. RMY 15
FASTEST MILE FOR YESTERDAY…………………11 SSE AT 6:48 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………12  S  AT 8:06 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..10 SSE AT 6:50 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..3.9 SSW
ASOS…………………..4.6
DAVIS………………….2.7 SSE [161 DEG.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.14
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….1.57  DEPARTURE……-0.59
ASOS…………..1.59
TOTAL PRECIPITATION FOR THE YEAR……….37.93  DEPARTURE……+0.75
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 Low temp since midnight is 63F; normal low is now 54F

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 18
HIGH 88F IN 1906
LOW 36F IN 1919
PRECIP 4.25 INCHES IN 1996
PEAK GUST 77e MPH WNW IN 1948

RECORDS FOR SEPTEMBER 19
HIGH 87F IN 1906,1983
LOW 37F IN 1929
PRECIP 3.69 INCHES IN 1936
PEAK GUST 55 MPH S IN 2012

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle