Thursday, September 7, 2023

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

THURSDAY, SEPTEMBER 7, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0516E
SUNSET:  1808E

HAZY, HOT, AND HUMID CONDITIONS WITH MID SUMMER-LIKE HEAT….

The triple H weather finally arrived, in September! It definitely
has the feel of midsummer out there today with the temperature
reaching the low 90s here on the summit early this afternoon.
Interestingly, today is only the 4th 90+ degree day of the year
here at Blue Hill, with 1 in June, and 2 in July!

So far the high is 91F. The record high for today is 92F set in
2007 and 2015. It appears we have an excellent chance to tie it,
and perhaps even beat it as most of our maxes lately have been
occurring between 2-4pm. Stay tuned! The overnight low this
morning was 72F, which is a new record high minimum should it
hold through midnight tonight. The previous record is 70F set in
1999.

The dew point has been in the low 70s all day, so this is of
course making it feel pretty nasty. The heat index has reached
the upper 90s now.

To make matters worse, there really isn’t much air movement
either. The wind has been rather light with an average speed
of only around 8mph. The highest gust so far today is around
15mph which occurred just before 6am this morning.

Visibility has been limited to around 15-30 today due to the
haziness.

The maximum temperature so far today has been 91F, which is
15 degrees above the normal high of 76F. The minimum temperature
since midnight is 72F, which is 13 degrees above the normal low
of 59F.

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Today’s Observations:

7 A.M.
Weather: Clear, few altocumulus/castellanus all quadrants,
few cirrus distant NE-SE
Temperature: 75F; Dew Point: 70F; Relative Humidity: 84%
Wind: WNW @ 8 kts
Sea-level pressure: 1009.9 mb; 29.82 in. Hg: rising, then more slowly
Visibility: 15 miles, hazy
6-hr Max temp: 75F
6-hr Min temp: 72F
24-hr Precip: 0.00 inches
BHO SA 1155 CLR 15 099/75/70/3008/982/ FEW AC/ACC ALQDS
FEW CI DSNT NE-SE HAZY/ 8/081 51014 10075 20072

10 A.M.
Weather: Clear, few cumulus distant ESE
Temperature: 85F; Dew Point: 71F; Relative Humidity: 65%
Wind: WNW @ 2 kts, wind light and variable
Sea-level pressure: 1010.4 mb; 29.84 in. Hg: rising, then steady
Visibility: 20 miles, hazy
3-hr Precip: 0.00 inches
BHO SA 1455 CLR 20 104/85/71/3002/984/ FEW CU DSNT ESE HAZY WND L/V/
8/100 51005

1 P.M.
Weather: Scattered cumulus
Temperature: 90F; Dew Point: 73F; Relative Humidity: 58%
Heat Index: 98F
Wind: WSW @ 4 kts, wind light and variable
Sea-level pressure: 1010.0 mb; 29.83 in. Hg: falling steadily
Visibility: 30 miles, hazy
6-hr Max temp: 91F
6-hr Min temp: 75F
6-hr Precip: 0.00 inches
BHO SA 1755 40 SCT 30 100/90/73/2404/983/ HAZY WND L/V/
HEAT INDEX 98/ 8/200 57004 10091 20075

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SUMMARY FOR WEDNESDAY, SEPTEMBER 6, 2023

TEMPERATURE (DEGREES F)
MAX…….89   NORMAL…..76
MIN…….70   NORMAL…..59
MEAN……80   NORMAL…..68

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………+12
TOTAL DEPARTURE FOR THE MONTH…………………+28 [+4.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY…………….0  DEPARTURE……..-1
TOTAL HEATING UNITS FOR THE MONTH…………….2  DEPARTURE……..-5
TOTAL HEATING UNITS FOR THE SEASON……………3  DEPARTURE…….-22
TOTAL HEATING UNITS LAST SEASON TO DATE……….5  DEPARTURE……..-2

COOLING DEGREE DAYS (SEASON: JAN 2023 THRU DEC 2023)
TOTAL COOLING UNITS FOR YESTERDAY……………15  DEPARTURE…….+11
TOTAL COOLING UNITS FOR THE MONTH……………50  DEPARTURE…….+24
TOTAL COOLING UNITS FOR THE SEASON………….620  DEPARTURE……..-2
TOTAL COOLING UNITS LAST SEASON TO DATE……..857  DEPARTURE……-237

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

F420C (Official)……….E17 WSW  @  10:52 P.M.
VECTOR #1 (1-Sec)……….17 SSW  @  05:56 P.M.
VECTOR #2 (1-Sec)……….18 SSW  @  05:53 P.M.
DAVIS #1……………….17 SSW  @  05:55 P.M.
DAVIS #2 ………………17 SSW  @  05:53 P.M.
RMY #1 (Instantaneous)…..18 SSW  @  05:56 P.M.
RMY #2 (Instantaneous)…..18 SSW  @  05:53 P.M.
MERLIN…………………17 S
RICHARDS (C5C) (Inst)……17      @  03:25 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………14 NNW  @  04:38 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..12      @  01:43 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..13      @  02:05 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………13 W    @  01:39 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………13 WNW  @  02:05 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..12 NNW  @  04:25 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..13 SSW  @  05:59 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………13      @  01:55 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..7.5 WNW [180 total miles] VECTOR #1………………8.0
VECTOR #2………………8.3
DAVIS #1……………….7.8 WNW
DAVIS #2……………….8.0 WNW
RMY #1…………………7.8 WNW
RMY #2…………………8.2 WNW
RICHARDS (C5C)………….8.2

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.13
TOTAL PRECIPITATION FOR THE MONTH………….TRACE DEPARTURE…..-0.71
TOTAL PRECIPITATION FOR THE YEAR…………..40.45 DEPARTURE…..+5.13

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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   73/52/63/-6/0.00/774/98             23 SSW VEC1 22 SSW RMY 21
9/2   79/56/68/-1/0.00/708/90             25 SW  VEC1 24 SW  RMY 26
9/3   85/61/73/+5/T/674/86                21 SW  VEC1 21 SW  RMY 21
9/4   85/68/77/+9/0.00/719/92             17 NW  VEC1 16 NW  RMY 16
9/5   86/68/77/+9/0.00/647/83             16 NNE VEC1 16 ENE RMY 16
9/6   89/70/80/+12/0.00/722/93            17 WSW VEC1 17 SSW RMY 18

9/7 The low since midnight is 72F, the daily normal low is 59F

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

RECORDS FOR SEPTEMBER 7
HIGH 92F IN 2007, 2015
LOW 40F IN 1888
PRECIP 2.91 INCHES IN 1891
PEAK GUST 58e MPH W IN 1941

RECORDS FOR SEPTEMBER 8
HIGH 97F IN 2015
LOW 42F IN 1978
PRECIP 1.51 INCHES IN 2011
PEAK GUST 45 MPH S IN 2012

TODAY’S REPORT PREPARED BY: Matt Douglas