Saturday, October 12, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, OCTOBER 12, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

SUB-TROPICAL STORM MELISSA WEAKENING AND MOVING OUT
TO SEA TODAY THOUGH LIGHT DRIZZLE AND LOW CLOUDS LINGER…

Steady light to moderate rain on Friday totaled over one
and a half inches, and light to moderate drizzle continued
on Saturday morning. The total rainfall since Wednesday
has been 1.93 inches with most of that being measured on
Friday. The daily rainfall on Friday of nearly 1.5 inches
will be a new record for the date. Drizzle mostly ended by
late morning today and the dense fog lifted from the summit
by early afternoon.
A peak wind gust of 41 mph NE was observed at 3:48 PM EST
on Friday, and the peak gust so far today has been 39 mph
just after midnight. Both the wind and temperature changed
very little on Friday with the temperature holding in the
range of 48F to 52F all day. The hourly wind speeds on
Friday were all in the 19-22 mph range and the wind direction
was northeast for the entire day. On Saturday, the visibility
has climbed from 1/8 mile earlier this morning to more than
70 miles to the northwest this afternoon as drier air finally
started to move into the area.

PRELIMINARY STATS FOR SEPTEMBER 2019

TEMPERATURE, Deg. F
Avg. Max. 73.6 [+2.0] Avg. Min. 54.5 [-0.1] Mean      64.1 [+1.0] 24-hour corrected mean: 63.4
Max. for month: 88F on the 23rd
Min. for month: 43F on the 19th

HEATING DEGREE DAYS
Total heating units:    81 [-36] Total for the season:   93 [-49] Total for last season:  87

COOLING DEGREE DAYS
Total cooling units:    58  [-2] Total for the season:  680 [+83] Total for last season: 863

PRECIPITATION, Inches
Total: 1.27 [-2.79] Greatest in 24 hrs: 0.37 ins. on the 2nd

WIND, mph
Avg. uncorrected wind speed: 10.3 mph
Avg. corrected wind speed:   10.9 mph
Prevailing wind direction:   SSW [11%] Peak gust and direction:     39 W on the 2nd

SUNSHINE:
Campbell-Stokes card minutes: 14790 minutes of possible 21582 or 69%
Astronomical total minutes: 15399 minutes of possible 22468 or 69%

Today’s Observations:

7 A.M.
Weather: Sky obscured in light drizzle and fog
Temperature: 50F; Dew Point: 50F; Wind: NNE at 14G27 kts,
Peak Wind: 31 MPH (27 kts) NE at 6:48 A.M.
Sea-level pressure: 29.97 ins. Hg, falling then increasing
Visibility: 1 1/2 miles, variable 1/2 to 2 1/2 miles
6-hr Max temp: 50F
6-hr Min temp: 49F
24-hr Precip: 1.53 ins.
BHO SA 1155 W2 X 11/2VL-F 148/50/50/0314G27/997/ VSBY 1/2V21/2
PK WND 0427/48/ 8//// 55003 60/// 70153 10050 20049

10 A.M.
Weather: Sky obscured in moderate drizzle and fog
Temperature: 51F; Dew Point: 51F; Wind: NNE at 9 kts,
Sea-level pressure: 29.98 ins. Hg, rising
Visibility: 1/8 mile
3-hr Precip: 0.08 ins.
BHO SA 1455 W2 X 1/8LF 152/51/51/0209/998/ 8//// 51004 6008/

1 P.M.
Weather: Overcast stratocumulus
Temperature: 52F; Dew Point: 50F; Wind: N at 8 kts,
Sea-level pressure: 29.96 ins. Hg, falling then more quickly
Visibility: 50 miles, visibility WNW-NW 70, E-SE 30
6-hr Max temp: 53F
6-hr Min temp: 50F
6-hr Precip: 0.10 ins.
BHO SA 1755 E10 OVC 50 147/52/50/0108/996/ VSBY WNW-NW 70
E-SE 30/ 8/5// 58005 6010/ 10053 20050

SUMMARY FOR FRIDAY, OCTOBER 11, 2019

TEMPERATURE (DEGREES F)
MAX…..52   NORMAL…..62
MIN…..48   NORMAL…..45
MEAN….50   NORMAL…..53

DEPARTURE FROM 30-YEAR NORMAL………………….-3
TOTAL DEPARTURE FOR THE MONTH………………….-8 [-0.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………15   DEPARTURE………+3
TOTAL HEATING UNITS FOR THE MONTH…………..118   DEPARTURE…….. +6
TOTAL HEATING UNITS FOR THE SEASON………….211   DEPARTURE……..-44
TOTAL HEATING UNITS LAST SEASON TO DATE……..141   DEPARTURE……..+70

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….0
TOTAL COOLING UNITS FOR THE MONTH……………2   DEPARTURE………-2
TOTAL COOLING UNITS FOR THE SEASON…………682   DEPARTURE……..+81
TOTAL COOLING UNITS LAST SEASON TO DATE…….874   DEPARTURE…….-192

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..41 NE  AT  3:48 P.M. *
AERO…………………….39 NE  AT  3:48 P.M. *
ASOS…………………….42 NE  AT 12:54 A.M.
DAVIS……………………42 NE  AT 12:52 A.M. RMY 41
FASTEST MILE FOR YESTERDAY………………….29 NE  AT  3:13 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….28 NNE AT  3:14 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………28 NNE AT  3:13 P.M.
AVERAGE WIND SPEED AND DIRECTION…………….20.4 NE
ASOS…………………….19.4 NE
DAVIS……………………19.7 NE [44 deg.] * Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….1.53  DEPARTURE……+1.38
ASOS…………..1.63
TOTAL PRECIPITATION FOR THE MONTH……….2.56  DEPARTURE……+0.93
ASOS…………..2.65
TOTAL PRECIPITATION FOR THE YEAR……….40.98  DEPARTURE……+0.26
ASOS………….40.88

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

9/01  73/56/65/-3/0.00/703/89                21 ENE AERO 14 ENE RMY 18
9/02  75/57/66/-2/0.37/165/21                39 W   AERO 41 W   RMY 41
9/03  77/61/69/+2/0.00/643/82                18 S   AERO 16 S   RMY N/A
9/04  83/61/72/+5/0.00/375/48                30 SW  AERO 28 SW  RMY 30
9/05  68/54/61/-6/0.00/513/66                23 NW  AERO 17 NW  RMY N/A
9/06  65/56/61/-6/0.03/054/07                37 ENE AERO 36 ENE RMY 36
9/07  70/51/61/-5/0.27/325/42                37 N   AERO 37 N   RMY N/A
9/08  73/53/63/-3/0.00/631/82                25 W   AERO 21 W   RMY N/A
9/09  71/54/63/-3/0.00/537/70                17 SE  AERO 16 SE  RMY 16
9/10  73/57/65/0/0.00/207/27                 25 S   AERO 25 S   RMY N/A
9/11  83/63/73/+8/0.00/419/55                31 SW  AERO 32 SW  RMY N/A
9/12  70/52/61/-4/0.11/015/02                29 ENE AERO 28 ENE RMY 28
9/13  65/49/57/-7/0.00/741/98                29 ENE AERO 27 ENE RMY 27
9/14  69/49/59/-5/0.19/030/04                36 S   AERO 37 S   RMY 37
9/15  78/62/70/+6/0.00/600/80                24 W   AERO 23 W   RMY 22
9/16  72/54/63/0/T/673/90                    25 WNW AERO 23 WNW RMY 25
9/17  67/49/58/-5/0.00/611/82                23 NW  AERO 23 N   RMY N/A
9/18  61/49/55/-7/0.00/579/78                26 NE  AERO 25 NE  RMY 25
9/19  67/43/55/-7/0.00/709/96                17 NE  AERO 18 NE  RMY N/A
9/20  78/50/64/+2/0.00/677/92                21 W   AERO 18 W   RMY 20
9/21  83/60/72/+11/0.00/689/94               21 WNW AERO 18 WNW RMY N/A
9/22  85/62/74/+13/0.00/687/94               24 SW  AERO 23 SW  RMY 25
9/23  88/65/77/+17/0.00/539/74               29 SSW AERO 28 SSW RMY 29
9/24  76/56/66/+6/0.04/616/85                26 W   AERO 26 W   RMY 27
9/25  73/50/62/+2/0.00/686/95                22 W   AERO 21 W   RMY 21
9/26  79/55/67/+8/0.25/388/54                38 SW  AERO 37 SW  RMY 39
9/27  72/50/61/+2/0.00/695/97                23 S   AERO 23 S   RMY 22
9/28  78/55/67/+9/0.00/664/93                31 S   AERO 29 S   RMY 30
9/29  75/53/64/+6/0.00/619/87                24 NW  AERO 23 NW  RMY 23
9/30  62/49/56/-2/0.00/609/86                23 NNE AERO 16 NNE RMY N/A

PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 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

10/01  67/52/60/+3/0.06/…/..               28 SW  AERO 25 SSW RMY 29
10/02  74/49/62/+5/0.42/…/..               30 ENE AERO 25 ENE RMY 28
10/03  51/46/49/-7/…./…/..               28 ENE AERO 26 ENE RMY N/A
10/04  59/40/50/-6/…./…/..               38 NNW AERO 38 NNW RMY 38
10/05  58/35/47/-9/0.00/…/..               21 N   AERO 18 SSW RMY N/A
10/06  65/44/55/0/0.00/…/..                36 SSW AERO 35 SSW RMY N/A
10/07  77/57/67/+12/0.12/…/..              47 SSW AERO 46 SSW RMY 49
10/08  60/52/56/+2/T/…/..                  22 NE  AERO 18 NW  RMY N/A
10/09  55/49/52/-2/…./…/..               43 NE  AERO 37 NE  RMY 44
10/10  54/47/51/-3/…./…/..     41 NE  AERO 37 NE  RMY 42
10/11  52/48/50/-3/…./000/00               41 NE  AERO 39 NE  RMY 41

The low since midnight is 49F, normal daily minimum is 44F

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):

RECORDS FOR OCTOBER 12
HIGH 87F IN 1954
LOW 31F IN 1906
PRECIP 1.53 INCHES IN 1948
SNOWFALL TRACE IN 1941
PEAK GUST 55 MPH NW IN 1963

RECORDS FOR OCTOBER 13
HIGH 84F IN 1930,1954
LOW 29F IN 2012
PRECIP 5.92 INCHES IN 1895
SNOWFALL 4.2 INCHES IN 1934
PEAK GUST 46e MPH W IN 1950

TODAY’S REPORT PREPARED BY: Mike Iacono / Ann Murphy