Wednesday, September 18, 2024

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

WEDNESDAY, SEPTEMBER 18, 2024
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0528E
SUNSET:  1748E

CLOUDS INCREASING WITH VERY LIGHT WIND AND WARM TEMPERATURES…

Clouds have been increasing and thickening as the day progresses.
We had some filtered sunshine this morning, but by early this
afternoon the clouds have thickened enough to now block the sun.

Despite the cloud cover, temperatures are still a bit above normal
with readings reaching the mid to upper 70s. More notably, the dew
point is considerably higher today than it has been the past
couple of days with values into the upper 50 to lower 60s.

The wind has been quite light, even spending quite a bit of time
this morning calm. The average speed for the day so far is only
around 5mph. The peak gust so far is 14mph, which occurred around
1:30am this morning.

Visibility has been decreasing as the day progresses thanks in
part to the higher dew point, but also due to haziness being
trapped under an inversion. The view started around 40 miles
early this morning, but has decreased to only around 30 miles
early this afternoon.

The maximum temperature so far today is 77F, which is 5 degrees
above the normal high of 72F. The minimum temperature since midnight
is 60F, which is 5 degrees above the normal low of 55F.

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Today’s Observations:

7 A.M.
Weather: Broken cirrus, thin stratus layer distant E-S-WNW,
thin smoke layer along horizon distant N-NE
Temperature: 63F; Dew Point: 59F; Relative Humidity: 87%
Wind: Calm
Sea-level pressure: 1020.9 mb; 30.15 in. Hg: falling unsteadily
Visibility: 40 miles
6-hr Max temp: 64F
6-hr Min temp: 60F
24-hr Precip:  0.00 inches
BHO SA 1155 E250 BKN 40 209/63/59/0000/015/ THN ST LYR DSNT E-S-WNW
THN K LYR ALG HRZN DSNT N-NE WND CALM/ 8/604 57001 10064 20060

10 A.M.
Weather: Scattered cirrostratus, broken cirrus, few stratus fractus
distant ESE-SSW
Temperature: 73F; Dew Point: 61F; Relative Humidity: 66%
Wind: Calm
Sea-level pressure: 1021.2 mb; 30.16 in. Hg: rising, then falling
Visibility: 35 miles, hazy
3-hr Precip: 0.00 inches
BHO SA 1455 210 SCT 250 BKN 35 212/73/61/0000/016/ FEW STFRA DSNT
ESE-SSW HAZY WND CALM/ 8/606 50003

1 P.M.
Weather: Overcast cirrostratus, few altocumulus distant WNW-NNE,
fog bank along shore distant NNE-ESE
Temperature: 76F; Dew Point: 58F; Relative Humidity: 54%
Wind: ESE @ 2 kts, wind light and variable
Sea-level pressure: 1019.9 mb; 30.12 in. Hg: steady, then falling
Visibility: 30 miles, hazy
6-hr Max temp: 77F
6-hr Min temp: 63F
6-hr Precip: 0.00 inches
BHO SA 1755 E220 OVC 30 199/76/58/1102/012/ FEW AC DSNT WNW-NNE
F BNK ALG SHR DSNT NNE-ESE HAZY WND L/V/ 8/657 58013 10077 20063

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SUMMARY FOR TUESDAY, SEPTEMBER 17, 2024

TEMPERATURE (DEGREES F)
MAX…….83  NORMAL…..72
MIN…….55  NORMAL…..55
MEAN……69  NORMAL…..64

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………..+5
TOTAL DEPARTURE FOR THE MONTH…………………….+18 [+0.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY…………….0  DEPARTURE……..-3
TOTAL HEATING UNITS FOR THE MONTH……………10  DEPARTURE…….-22
TOTAL HEATING UNITS FOR THE SEASON…………..21  DEPARTURE…….-29
TOTAL HEATING UNITS LAST SEASON TO DATE………12  DEPARTURE……..+9

COOLING DEGREE DAYS (SEASON: JAN 2024 THRU DEC 2024)
TOTAL COOLING UNITS FOR YESTERDAY…………….4  DEPARTURE……..+2
TOTAL COOLING UNITS FOR THE MONTH……………55  DEPARTURE……..-3
TOTAL COOLING UNITS FOR THE SEASON………….749  DEPARTURE…….+95
TOTAL COOLING UNITS LAST SEASON TO DATE……..689  DEPARTURE…….+60

PEAK WIND GUST (MPH):
Note: Instruments designated #1 = Main Tower, #2 = South Tower,
F420C, Contacting, Merlin, and Richards are all on Main Tower.
E=Estimated

F420C (Official)……….E16 SW   @   10:35 P.M.
VECTOR #1 (1-Sec)……….14 S    @   07:04 P.M.
VECTOR #2 (1-Sec)……….15 S    @   06:55 P.M.
DAVIS #1……………….15 S    @   07:04 P.M.
DAVIS #2 ………………19 S    @   06:29 P.M.
RMY #1 (Instantaneous)…..15 S    @   07:04 P.M.
RMY #2 (Instantaneous)…..15 S    @   06:55 P.M.
MERLIN…………………13 S
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………12 SW   @   01:02 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..12      @   01:03 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..12      @   06:34 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………12 SW   @   01:03 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 S    @   06:34 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..12 SW   @   01:03 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..12 S    @   06:34 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..5.5 SW [133 total miles] VECTOR #1………………6.5
VECTOR #2………………6.5
DAVIS #1……………….5.9 SSW
DAVIS #2……………….6.1 SSW
RMY #1…………………6.3 SSW
RMY #2…………………6.6 SSW
RICHARDS (C5C)………….OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.15
TOTAL PRECIPITATION FOR THE MONTH…………..0.04 DEPARTURE…..-2.08
TOTAL PRECIPITATION FOR THE YEAR (2024)…….41.25 DEPARTURE…..+4.52

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PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN)/SUN(%)/PEAK GUST/VEC1/RMY GUST
PEAK GUST: F420C (Official)
VEC1: Vector #1 1-second gust
RMY:  R.M. Young #1 wind gust recording system (Instantaneous)
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

9/1   82/67/75/+6/T/244/31                28 SSW VEC1 27 SW  RMY 28
9/2   79/56/68/-1/0.00/644/82             31 NNW VEC1 31 NNW RMY 32
9/3   74/49/62/-6/0.00/766/98             23 NW  VEC1 23 NNW RMY 23
9/4   80/56/68/0/0.00/732/94              18 ESE VEC1 19 SE  RMY 18
9/5   77/58/68/0/0.00/737/95              20 ESE VEC1 19 ESE RMY 19
9/6   73/58/66/-2/0.00/240/31             22 E   VEC1 21 ENE RMY 23
9/7   77/56/67/0/0.04/301/39              34 WNW VEC1 31 WNW RMY 33
9/8   70/50/60/-7/0.00/753/98             35 W   VEC1 35 W   RMY 34
9/9   75/51/63/-4/0.00/727/95             31 WNW VEC1 28 WNW RMY 30
9/10  78/56/67/+1/0.00/717/94             21 NW  VEC1 20 SW  RMY 21
9/11  78/53/66/0/0.00/714/94              20 S   VEC1 19 S   RMY 18
9/12  82/58/70/+4/0.00/…/..             20 S   VEC1 19 S   RMY 20
9/13  85/59/72/+7/0.00/…/..             21 SSW VEC1 20 SSW RMY 20
9/14  81/61/71/+6/0.00/…/..             21 ENE VEC1 20 ENE RMY 21
9/15  78/60/69/+4/0.00/…/..             23 SE  VEC1 23 SE  RMY 25
9/16  83/55/69/+5/0.00/…/..             22 SSW VEC1 21 SSW RMY 21
9/17  83/55/69/+5/0.00/../..              16 SW  VEC1 14 S   RMY 15

9/18  The low since midnight is 60F, the daily normal low is 55F.

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SEPTEMBER DAILY RECORDS TO DATE

NONE.

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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: Matt Douglas