Sunday, September 17, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, SEPTEMBER 17, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

SKIES CLEAR IN AFTERNOON AFTER FOGGY START TO THE DAY

Thick fog limited visibility to 1/16 mile this morning
and persisted through the 10:00AM observation when
visibility was 1/4 mile.  The fog lifted to reveal
mostly sunny skies with few cumulus by the afternoon.
Winds have again been very light today and have measured
only 1-3 miles per hour for most of the day.  Dew points
measured in the low 60s making for slightly more comfortable
conditions than in the previous days.

Today’s Observations:

7 A.M.
Weather: Sky obscured due to thick fog, thin spots in overcast overhead
Temperature: 62F; Dew Point: 62F; Wind: estimated S at 3 kts,
Wind speed: Light
Sea-level pressure: 30.19 ins. Hg, rising, then more quickly
Visibility: 1/16 mile
6-hr Max temp: 64F
6-hr Min temp: 61F
24-hr Precip:  Trace
BHO SA 1155 W3 X 1/16F 224/62/62/E1903/019/ THN SPTS IOVC OVHD WND LGT/
8//// 53011 10064 20061

10 A.M.
Weather: Sky obscured due to fog
Temperature: 67F; Dew Point: 64F; Wind: estimated SSE at 1 kt,
Wind speed: Light
Sea-level pressure: 30.19 ins. Hg, rising then falling
Visibility: 1/4 mile, except 1/8 mile SW
BHO SA 1455 W3 X 1/4F 223/67/64/E1601/019/ VSBY 1/8 SW WND LGT/
8//// 58001

1 P.M.
Weather: Few cumulus in all directions
Temperature: 77F; Dew Point: 63F; Wind: estimated NE at 2 kts,
Wind: Light and variable
Sea-level pressure: 30.16 ins. Hg, falling, then more quickly
Visibility: 20 miles, hazy
6-hr Max temp: 78F
6-hr Min temp: 62F
BHO SA 1755 CLR 20 213/77/63/E0502/016/ FEW CU ALQDS HAZY WND L/V/
8/100 58010 10078 20062

SUMMARY FOR SATURDAY, SEPTEMBER 16, 2017

TEMPERATURE (DEGREES F)
MAX…..78   NORMAL…..72
MIN…..65   NORMAL…..55
MEAN….72   NORMAL…..63

DEPARTURE FROM 30-YEAR NORMAL…………………….+9
TOTAL DEPARTURE FOR THE MONTH……………………+10 [+0.4 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………7   DEPARTURE……….+5
TOTAL COOLING UNITS FOR THE MONTH…………..53   DEPARTURE……….+8
TOTAL COOLING UNITS FOR THE SEASON…………660   DEPARTURE………+78
TOTAL COOLING UNITS LAST SEASON TO DATE…….855   DEPARTURE……..-195

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….-4
TOTAL HEATING UNITS FOR THE MONTH…………..31   DEPARTURE……….-4
TOTAL HEATING UNITS FOR THE SEASON………….57   DEPARTURE……….-3
TOTAL HEATING UNITS LAST SEASON TO DATE……..17   DEPARTURE………+40

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….14  E  AT  5:30 P.M.
AERO…………………….9  E  AT  5:30 P.M.
ASOS……………………13  S  AT  8:45 P.M.
DAVIS…………………..12 SSE AT  8:53 P.M. RMY 12
FASTEST MILE FOR YESTERDAY………………….9  E  AT  5:39 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….9 SW  AT 11:01 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………8 SSE AT  8:54 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..3.5 WNW
ASOS…………………..4.3
DAVIS………………….1.7 SSE [162 DEG.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…Trace  DEPARTURE……-0.14
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….1.57  DEPARTURE……-0.45
ASOS…………..1.59
TOTAL PRECIPITATION FOR THE YEAR……….37.93  DEPARTURE……+0.89
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 Low temp since midnight is 61F; 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 17
HIGH 87F IN 2015
LOW 38F IN 1959
PRECIP 2.73 INCHES IN 1933
PEAK GUST 60 MPH WNW IN 1999

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

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle