Tuesday, September 18, 2018
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, SEPTEMBER 18, 2018
ALL TIMES ARE IN EASTERN STANDARD TIME
SIGNIFICANT RAINFALL AND THUNDERSTORMS FROM THE REMNANTS
OF HURRICANE FLORENCE ….
We observed heavy rain and thunderstorms today atop
Great Blue Hill. By 1 P.M. we measured a storm total
of 3.15 inches of rain, with light rain still in progress.
There are only four other instances this decade where
more than 3 inches of rain fell in one day (see below).
Most of the rain that was measured occurred between 10 and
11 A.M., when almost 2 inches of rain fell. During this time,
there was a wind shift from S to NNW and frequent lightning.
Between 11 A.M and noon, another inch of rain fell.
After noontime, the wind went calm and intensity of
precipitation decreased.
Today began with fog obscuring visibility to 20 miles.
Fog increased throughout the day, bringing visibility
to 5 miles by 1 P.M. Pressure decreased rapidly since
this morning, dropping almost 3 millibars by noontime.
The high so far today is 74F, 3 degrees above
the daily normal of 71F. The low since midnight is 67F,
13 degrees above the normal minimum of 54F.
Here are the four other calendar days this decade with
more than 3 inches of liquid precipitation at the
Blue Hill Observatory:
3.23 inches on 9 December 2014
3.66 inches on 23 October 2014
3.28 inches on 7 June 2013
4.95 inches on 14 March 2010
Today’s Observations:
7 A.M.
Weather: Light drizzle, overcast stratus
Temperature: 71F; Dew Point: 71F; Wind: S at 16G22 kts
Sea-level pressure: 29.80 ins. Hg, falling, then more slowly
Visibility: 20 miles, distant fog in all directions
6-hr Max temp: 71F
6-hr Min temp: 69F
24-hr Precip: 0.07 ins.
BHO SA 1155 E20 OVC 20L- 092/71/71/1916G22/980/ DSNT FG ALQDS/ 8/6// 56027
70007 10071 20069
10 A.M.
Weather: Light drizzle becoming light rain
Temperature: 74F; Dew Point: 72F; Wind: S at 20G27 kts,
Peak wind: 27 kts (31 mph) at 9:26 A.M.
Sea-level pressure: 29.73 ins. Hg, falling, then more rapidly
Visibility: 7 miles
3-hr Precip: 0.02
BHO SA 1455 W3 X 7R- 067/74/72/1920G27/973/ THN FOG PK WND 1927/26
L-BCMG R-UKN/ 8//// 60002 56025
1 P.M.
Weather: Thunderstorm with continued distant lightning,
light rain
Temperature: 67F; Dew Point: 67F; Wind: SSW at 5 kts
Sea-level pressure: 29.72 ins. Hg, falling steadily
Visibility: 5 miles, fog
6-hr Max temp: 74F
6-hr Min temp: 67F
6-hr Precip: 3.08 ins.
BHO SA 1755 W3 X 5R-F 066/67/67/2105/972/ FOG TS CTD R CTD DSNT
LTG ALQDS/ 8//// 60308 58001 10074 20067
SUMMARY FOR MONDAY, SEPTEMBER 17, 2018
TEMPERATURE (DEGREES F)
MAX…..82 NORMAL…..71
MIN…..64 NORMAL…..54
MEAN….73 NORMAL…..63
DEPARTURE FROM 30-YEAR NORMAL………………….+10
TOTAL DEPARTURE FOR THE MONTH………………….+68 [+3.8 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0 DEPARTURE………+4
TOTAL HEATING UNITS FOR THE MONTH…………..18 DEPARTURE……..-21
TOTAL HEATING UNITS FOR THE SEASON………….18 DEPARTURE……..-46
TOTAL HEATING UNITS LAST SEASON TO DATE……..57 DIFFERENCE…….-39
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………8 DEPARTURE……….+6
TOTAL COOLING UNITS FOR THE MONTH…………..96 DEPARTURE………+50
TOTAL COOLING UNITS FOR THE SEASON…………849 DEPARTURE……..+266
TOTAL COOLING UNITS LAST SEASON TO DATE…….665 DIFFERENCE…….+184
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY…………………22 SSW AT 3:27 P.M.
AERO……………………..22 SSW AT 3:24 P.M.
ASOS……………………..23 SSW AT 3:29 P.M.
DAVIS…………………….26 M AT 3:28 P.M. RMY N/A
FASTEST MILE FOR YESTERDAY…………………..16 SSW AT 3:27 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………..17 SSW AT 3:28 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………….20 M AT 3:28 P.M.
AVERAGE WIND SPEED AND DIRECTION…………….9.9 S
ASOS…………………….10.4
DAVIS……………………10.8 **
**Davis direction malfunctioning
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.07 DEPARTURE……-0.07
ASOS…………..0.07
TOTAL PRECIPITATION FOR THE MONTH……….3.03 DEPARTURE……+0.87
ASOS…………..3.05
TOTAL PRECIPITATION FOR THE YEAR……….40.98 DEPARTURE……+3.98
ASOS………….42.54
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 75/58/67/-1/0.00/521/66 17 NE AERO 15 NE RMY 16
9/02 83/61/72/+4/0.00/684/87 20 SSW AERO 18 SSW RMY N/A
9/03 92/68/80/+13/0.00/650/83 24 WSW AERO 22 WSW RMY 25
9/04 88/70/79/+12/0.00/695/89 17 W AERO 16 W RMY 17
9/05 89/67/78/+11/0.00/638/82 23 SSW AERO 23 SSW RMY 25
9/06 92/70/81/+14/0.56/488/63 29 NNW AERO 29 NNW RMY N/A TSTM
9/07 70/63/67/+1/0.01/000/00 24 NE AERO 22 NE RMY N/A
9/08 68/54/61/-5/0.00/031/04 22 NE AERO 18 NE RMY 21
9/09 61/53/57/-9/0.00/000/00 23 NE AERO 21 NE RMY N/A
9/10 62/56/59/-6/…./…/.. 30 E AERO 28 E RMY 28
9/11 75/61/68/+3/…./…/.. 23 E AERO 21 E RMY N/A TSTM
9/12 69/63/66/+1/…./…/.. 21 ENE AERO 21 ENE RMY 21 TSTM
9/13 68/62/65/+1/…./…/.. 21 NE AERO 21 NE RMY N/A TSTM
9/14 75/61/68/+4/…./…/.. 13 NE AERO 12 ENE RMY 12
9/15 76/62/69/+5/0.01/…/.. 14 SW AERO 13 SW RMY 13
9/16 84/61/73/+10/…./…/.. 15 S AERO 14 S RMY N/A
9/17 82/64/73/+10/…./…/.. 22 SSW AERO 22 SSW RMY N/A
9/18 Low temp since midnight is 67F; normal low is now 54F
DAILY RECORDS FOR SEPTEMBER
09/04/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F,
BREAKS PREVIOUS RECORD OF 68F SET IN 1937 AND 1959
09/06/18: DAILY RECORD HIGH MAXIMUM TEMPERATURE OF 92F,
TIES PREVIOUS RECORD OF 92F SET IN 1900
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: Benjamin Turner
