Friday, September 11, 2020

| September 11, 2020 | Reply

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

FRIDAY, SEPTEMBER 11, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

A CHANGEABLE DAY ATOP GREAT BLUE HILL..

After sweating through tropical warmth and humidity
this week, fall weather has finally returned.
Temperatures began in the lower-70s very early this
morning. Our long-awaited cold front then swept through
the region resulting in crashing temperatures and dew
points. We so far we have bottomed out at 57 degrees and
a minimum dew point of 52 degrees…very refreshing!

It is worth mentioning yesterday’s near recording setting
event. We only managed to hit 69 degrees as the low
temperature. This ties for 2nd highest minimum temperature
on record for this date. 71 degrees remains the undefeated
top spot since 2016.

Overall, skies have remained predominantly overcast with
fluctuating visibility. Like yesterday, a sprinkle was felt
in between observations. Winds are now gusting from the north
peaking at so far at 24 MPH compliments of the early morning
cold front.

The high since midnight is 72F, 1 degree below the daily
normal max of 73F. The low since midnight is 57F, which
is 1 degree above the normal low of 56F.

PRELIMINARY STATS FOR AUGUST 2020

TEMPERATURE, Deg. F
Avg. Max. 82.5 [+3.3]
Avg. Min. 64.3 [+2.5]
Mean      73.4 [+2.9]
24-hour corrected mean: 72.3
Max. for month: 94F on the 10th
Min. for month: 54F on the 31st

HEATING DEGREE DAYS
Total heating units:     2 [-14]
Total for the season:    3 [-22]
Total for last season:  12

COOLING DEGREE DAYS
Total cooling units:    270  [+84]
Total for the season:   757  [+220]
Total for last season:  622

PRECIPITATION, Inches
Total: 3.74 [-0.29]
Greatest in 24 hrs: N/A

WIND, mph
Avg. uncorrected wind speed: 10.0 mph
Avg. corrected wind speed:   10.6 mph
Prevailing wind direction:   SSW [12%]
Peak gust and direction:     67 SSE on the 4th

SUNSHINE:
Campbell-Stokes card minutes: 15366 minutes of a possible 24780 or 62%
Astronomical total minutes: 15940 minutes of a possible 25709 or 62%

Today’s Observations:

7 A.M.
Weather: Overcast Stratus (few lower stratocumulus distant W;
few breaks in overcast SW-NW)
Temperature: 64F; Dew Point: 60F; Relative Humidity: 87%
Wind: N at 10G18 kts
Sea-level pressure: 30.17 ins. Hg: rising, then rising more slowly
Visibility: 35 miles (except N 15 miles & NE-S 10 miles, distant fog)
6-hr Max temp: 72F
6-hr Min temp: 63F
24-hr Precip: 0.28 ins.
BHO SA 1155 E24 OVC 35 217/64/60/3610G18/017/ FEW LWR SC DSNT W
FEW BINOVC SW-NW VSBY N 15 NE-S 10 THN F ALQDS/ 8/6// 51022
70028 10072 20063

10 A.M.
Weather: Overcast Stratus
Temperature: 58F; Dew Point: 56F; Relative Humidity: 94%
Wind: NE at 9G19 kts
Sea-level pressure: 30.21 ins. Hg: rising, then rising more slowly
Visibility: 20 miles (except E-S 2 miles & S-NW 5 miles, distant fog)
3-hr Precip: 0.01 ins.
BHO SA 1455 E17 OVC 20 231/58/56/0409G19/021/ VSBY E-S 2 S-NW 5
THN F ALQDS/ 8/6// 51014 6001/

1 P.M.
Weather: Overcast Stratus Fractus (few breaks in overcast W-N)
Temperature: 60F; Dew Point: 52F; Relative Humidity: 75%
Wind: NE at 7 kts
Sea-level pressure: 30.20 ins. Hg: rising, then rising more slowly
Visibility: 75 miles
6-hr Max temp: 64F
6-hr Min temp: 57F
6-hr Precip: 0.01 ins.
BHO SA 1755 E25 OVC 75 227/60/52/0507/020/ FEW BINOVC W-N/ 8/6//
51004 6001/ 10064 20057

SUMMARY FOR THURSDAY, SEPTEMBER 10, 2020

TEMPERATURE (DEGREES F)
MAX…..81   NORMAL…..74
MIN…..69   NORMAL…..57
MEAN….75   NORMAL…..65

DEPARTURE FROM 30-YEAR NORMAL……………. +10
TOTAL DEPARTURE FOR THE MONTH……………. +30 [+2.8 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY………… 10  DEPARTURE……+7
TOTAL COOLING UNITS FOR THE MONTH………… 48  DEPARTURE…..+16
TOTAL COOLING UNITS FOR THE SEASON………..805  DEPARTURE….+236
TOTAL COOLING UNITS LAST SEASON TO DATE……634  DEPARTURE….+171

PEAK WIND GUST FOR YESTERDAY (MPH)
420C/Official…………….21 SSW AT  6:04 P.M.
AERO…………………….21 SSW AT  5:59 P.M.
ASOS…………………….21 SSW AT  5:59 P.M.
DAVIS……………………21 S   AT  3:49 P.M.
RMY n/a  MERLIN n/a
FASTEST MILE FOR YESTERDAY………………….15 SSW AT  5:57 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….16 S   AT  5:55 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………15 SW  AT 12:05 P.M.
AVERAGE WIND SPEED AND DIRECTION……………8.5 SSW
ASOS……………………8.9
DAVIS…………………..8.0 SSW [211 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.28  DEPARTURE….+0.15
ASOS…………..0.27
TOTAL PRECIPITATION FOR THE MONTH……….0.51  DEPARTURE….-0.71
ASOS…………..0.51
TOTAL PRECIPITATION FOR THE YEAR……….33.32  DEPARTURE….-2.92
ASOS………….34.09

PRELIMINARY CLIMATE SUMMARY FOR AUGUST 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

08/01  87/66/77/+5/0.00/866/100            18 S    AERO 21 S    RMY 19
08/02  85/69/77/+5/0.02/320/37             36 S    AERO 37 S    RMY 38
08/03  91/75/83/+11/0.00/715/83            36 WSW  AERO 38 SW   RMY 36
08/04  83/71/77/5/0.21/094/11              67 SSE  AERO 71 S    RMY 70
08/05  90/68/79/+7/0.00/668/78             28 SW   AERO 30 SW   RMY 29
08/06  84/65/75/3/0.00/701/82   20 W    AERO 17 W    RMY 19
08/07  79/65/72/0/T/136/16                 16 NE   AERO 16 NE   RMY N/A
08/08  83/64/74/+2/0.00/612/72             20 S    AERO 20 S    RMY 19
08/09  90/65/78/+6/0.00/661/78             26 SSW  AERO 26 SSW  RMY 26
08/10  94/69/82/+11/0.00/727/86            22 W    AERO 20 W    RMY 20
08/11  92/72/82/+11/0.00/708/84            31 SSW  AERO 35 SSW  RMY 31  TSTM
08/12  93/74/84/+13/0.00/647/77            22 SSW  AERO 22 SW   RMY 19
08/13  88/71/80/+9/0.00/528/63             18 ENE  AERO 18 NE   RMY 18
08/14  82/67/75/+4/0.00/618/74             23 ENE  AERO 23 ENE RMY N/A
08/15  67/62/65/-6/T/000/00                33 NNE  AERO 32 NNE  RMY N/A
08/16  69/62/66/-5/…./000/00             26 ENE  AERO 28 ENE  RMY 26
08/17  73/59/66/-5/…./339/41             25 NE   AERO 24 NE   RMY N/A
08/18  84/63/74/+3/…./784/95             23 W    AERO 23 W    RMY 24
08/19  81/59/70/0/0.03/526/64              26 W    AERO 28 W    RMY 27
08/20  80/56/68/-2/0.00/804/98             22 W    AERO 21 W    RMY 22
08/21  88/61/75/+5/0.00/719/88             28 SW   AERO 26 SW   RMY 28
08/22  85/66/76/+6/0.26/521/64             18 NNE  AERO 16 S    RMY 16
08/23  89/63/76/+6/2.21/552/68             60 WNW  AERO 53 WNW  RMY 58  TSTM HAIL
08/24  87/67/77/+7/0.00/493/61             18 S    AERO 18 S    RMY 19  TSTM
08/25  86/65/76/+7/0.01/492/61             35 NNW  AERO 37 NNW  RMY 35
08/26  74/56/65/-4/0.00/780/97             29 NW   AERO 32 NW   RMY N/A
08/27  68/57/63/-6/0.33/008/01             18 SSE  AERO 20 SSE  RMY 20  TSTM
08/28  80/59/70/+1/0.00/559/70             20 W    AERO 20 W    RMY N/A
08/29  74/65/70/+1/0.06/000/00             32 W    AERO 32 W    RMY N/A
08/30  75/57/66/-2/0.00/793/100            36 W    AERO 36 W    RMY N/A
08/31  75/54/65/-3/0.00/569/72             20 S    AERO 20 S    RMY 20

DAILY RECORDS FOR AUGUST 2020

8/23/20: DAILY RECORD HIGH MAXIMUM TEMPERATURE OF 89F,
BREAKS PREVIOUS RECORD of 88F SET IN 1918, 1947, 1949, 1996

8/23/20: DAILY RECORD PRECIPITATION OF 2.21 INS,
BREAKS PREVIOUS RECORD OF 2.09 INS SET IN 2010

8/23/20: DAILY RECORD PEAK WIND GUST OF 60 MPH,
TIES PREVIOUS RECORD OF 60 MPH SET IN 1940

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

09/01  76/59/68/0/0.00/…/..              22 SSE  AERO 21 SE   RMY 20
09/02  69/59/64/-4/…/…/..              23 SSE  AERO 23 SSE  RMY 24
09/03  75/66/71/+4/…/…/..              22 SSW  AERO 21 SSW  RMY n/a
09/04  82/62/72/+5/0.00/…/..             26 WNW  AERO 26 WNW  RMY 25
09/05  76/55/66/-1/0.00/…/..             25 W    AERO 25 W    RMY 24
09/06  78/58/68/+1/0.00/…/..             24 W    AERO 24 W    RMY n/a
09/07  79/61/70/+4/0.00/…/..             27 SSE  AERO 30 SSE  RMY 28
09/08  82/61/72/+6/0.00/…/..             17 S    AERO 16 S    RMY 17
09/09  80/62/71/+5/0.00/…/..             16 S    AERO 15 S    RMY 16
09/10  81/69/75/+10/0.29/…/..            21 SSW  AERO 21 SSW  RMY n/a

09/11 The low since midnight is 57F, the daily normal low is 56F

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

RECORDS FOR SEPTEMBER 11
HIGH 93F IN 1983, 2013
LOW 37F IN 1917
PRECIP 5.23 INCHES IN 1954 (HURRICANE EDNA)
PEAK GUST 101 MPH NW IN 1954 (HURRICANE EDNA)

RECORDS FOR SEPTEMBER 12
HIGH 92F IN 1961
LOW 42F IN 1958,1967,1985
PRECIP 2.79 INCHES IN 1960 (HURRICANE DONNA)
PEAK GUST 140 MPH SSE IN 1960 (HURRICANE DONNA)

TODAY’S REPORT PREPARED BY: Andrew Swanson

Category: Daily Discussions

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