Wednesday, May 13, 2020

| May 14, 2020 | Reply

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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 13, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

AN ALMOST CLEAR DAY WITH GREAT VISIBILITY AND A
NEAR FREEZING OVERNIGHT LOW….

Today we observed a few fair weather cumulus with skies
being completely clear at the 7 A.M. observation. There
was a good westerly breeze, with a max gust of 38 mph.
The overnight low was 32.4F, setting a new record for the
daily minimum temperature. The old record was 35F, set in 2005.
Conditions remain dry, with a humidity of 22% by 1 P.M.

The high so far today is 57F, this is 9 degrees below the
daily normal high of 66F. The low since midnight is 32F,
which is 15 degrees below the daily normal low of 47F.

The temperature of 32F this morning was also the second
latest freezing temperature ever observed at Blue Hill,
behind only 30F on May 16th, 1936.

BHO Latest Freezing Temperature, deg F (1885-2020):

1) 30F on 16 May 1936
2) 32F on 13 May 2020
3) 29F on 12 May 1907
30F on 12 May 1963
5) 28F on 11 May 1900
31F on 11 May 1907
31F on 11 May 1913
30F on 11 May 1923
9) 29F on 10 May 1900
31F on 10 May 1902
31F on 10 May 1947
32F on 10 May 1966
32F on 10 May 1977
31F on 10 May 2020

PRELIMINARY STATS FOR APRIL 2020

TEMPERATURE, Deg. F
Avg. Max. 50.6 [-5.1]
Avg. Min. 35.8 [-1.9]
Mean      43.4 [-3.3]
24-hour corrected mean: 42.9
Max. for month: 63F on the 7th
Min. for month: 28F on the 1st

HEATING DEGREE DAYS
Total heating units:    648 [+97]
Total for the season:  5521 [-514]
Total for last season: 5900

PRECIPITATION, Inches
Total: 7.71 [+3.16]
Greatest in 24 hrs: 2.23 ins. on the 3rd-4th

SNOWFALL, Inches
Total: 4.3 [+1.3]
Greatest in 24 hrs: 4.3 ins. on the 18th

WIND, mph
Avg. uncorrected wind speed: 13.9 mph
Avg. corrected wind speed:   14.3 mph
Prevailing wind direction:   W [24%]
Peak gust and direction:     79 S on the 13th

SUNSHINE:
Campbell-Stokes card minutes: 8358 minutes of possible 23250 or 36%
Astronomical total minutes: 8676 minutes of possible 24148 or 36%

Today’s Observations:

7 A.M.
Weather: Clear
Temperature: 42F; Dew Point: 22F; Relative Humidity: 22%
Wind: WNW at 9 kts
Sea-level pressure: 30.21 ins. Hg: rising
Visibility: 80 miles
6-hr Max temp: 57F
6-hr Min temp: 42F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 CLR 80 231/42/22/2909/021/ 52023 10057 20042

10 A.M.
Weather: Few cumulus
Temperature: 51F; Dew Point: 21F; Relative Humidity: 30%
Wind: WNW at 11G27 kts, peak wind 35 mph at 9:39 A.M.
Sea-level pressure: 30.20 ins. Hg: falling
Visibility: 80 miles
3-hr Precip:  0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 CLR 80 228/51/21/3011G27/020/ FEW CU ALQDS PK
WND 2830/39/ 8/100 58003

1 P.M.
Weather: Few cumulus
Temperature: 56F; Dew Point: 18F; Relative Humidity: 22%
Wind: W at 14G26 kts, peak wind 33 mph at 12:29 P.M.
Sea-level pressure: 30.16 ins. Hg: falling
Visibility: 75 miles
6-hr Max temp: 57F
6-hr Min temp: 42F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 CLR 75 214/56/18/2814G26/016/ FEW CU ALQDS PK
WND 2929/29/ 8/100 58014 10057 20042

SUMMARY FOR TUESDAY, MAY 12, 2020

TEMPERATURE (DEGREES F)
MAX…..55   NORMAL…..65
MIN…..37   NORMAL…..47
MEAN….46   NORMAL…..56

DEPARTURE FROM 30-YEAR NORMAL………………-10
TOTAL DEPARTURE FOR THE MONTH………………-33 [-3.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………19  DEPARTURE…….+10
TOTAL HEATING UNITS FOR THE MONTH…………..162  DEPARTURE…….+29
TOTAL HEATING UNITS FOR THE SEASON…………5683  DEPARTURE……-484
TOTAL HEATING UNITS LAST SEASON TO DATE…….6064  DEPARTURE……-381

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……………2  DEPARTURE……..-4
TOTAL COOLING UNITS LAST SEASON TO DATE……….0  DEPARTURE……..+2

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..37 W   AT  3:55 P.M.
AERO…………………….37 W   AT  4:00 P.M.
ASOS…………………….40 WNW AT  4:18 P.M.
DAVIS……………………39 W   AT  3:50 P.M. RMY 37
FASTEST MILE FOR YESTERDAY………………….29 W   AT  3:58 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….29 WNW AT  3:58 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………31 W   AT  3:58 P.M.
AVERAGE WIND SPEED AND DIRECTION…………….17.3 WNW
ASOS…………………….16.5
DAVIS……………………17.6 WNW [288 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.13
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….1.61  DEPARTURE……+0.14
ASOS…………..1.60
TOTAL PRECIPITATION FOR THE YEAR……….18.65  DEPARTURE……-1.37
ASOS………….19.20

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE MONTH…………..Trace  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE SEASON…………..31.9  DEPARTURE……-30.8

PRELIMINARY CLIMATE SUMMARY FOR APRIL CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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

04/01  42/28/35/-6/0.00/0.0/008/01         28 NE  AERO 28 NE  RMY 30
04/02  46/35/41/0/0.34/0.0/000/00          39 NW  AER0 40 NW  RMY 41
04/03  42/38/40/-2/2.14/0.0/000/00         48 NE  AERO 53 NE  RMY 49
04/04  46/36/41/-1/0.24/0.0/278/36         38 NE  AERO 38 NE  RMY N/A
04/05  55/36/46/+3/0.00/0.0/039/05         22 S   AERO 21 S   RMY 21
04/06  61/40/51/+8/0.00/0.0/732/94         29 NW  AERO 30 NW  RMY 29
04/07  63/42/53/+10/0.00/0.0/649/83        29 W   AERO 30 W   RMY 28
04/08  50/41/46/+2/0.08/T/047/06           23 S   AERO 22 S   RMY 22
04/09  47/37/42/-2/0.66/T/000/00           58 W   AERO 58 W   RMY 56
04/10  47/35/41/-4/0.02/T/324/41           48 W   AERO 50 W   RMY 53
04/11  51/33/42/-3/0.00/0.0/730/92         38 WNW AERO 39 WNW RMY 40
04/12  60/33/47/+2/0.00/0.0/326/41         38 S   AERO 40 S   RMY N/A
04/13  59/50/55/+9/1.42/0.0/000/00         79 S   AERO 83 S   RMY 78
04/14  57/41/49/+3/0.00/0.0/641/80         41 W   AERO 40 W   RMY N/A
04/15  52/36/44/-3/0.02/0.0/450/56         37 W   AERO 36 W   RMY 37
04/16  47/32/40/-7/T/T/379/47              33 WNW AERO 33 WNW RMY 32
04/17  49/29/39/-8/0.01/0.0/591/73         41 W   AERO 39 W   RMY 41
04/18  37/31/34/-14/0.73/4.3/000/00        29 NE  AERO 25 NE  RMY 25
04/19  60/31/46/-2/0.00/0.0/693/85         40 SSW AERO 40 SSW RMY 41
04/20  49/37/43/-6/0.00/0.0/000/00         25 ENE AERO 22 W   RMY N/A
04/21  53/33/43/-6/0.34/T/271/33           52 S   AERO 52 S   RMY 52
04/22  43/30/37/-12/0.00/0.0/601/73        51 W   AERO 50 W   RMY 50
04/23  55/29/42/-8/0.00/0.0/545/66         31 W   AERO 29 W   RMY N/A
04/24  42/37/40/-10/0.34/0.0/000/00        31 NNE AERO 29 NNE RMY 29
04/25  60/38/49/-1/0.00/0.0/557/67         25 S   AERO 24 S   RMY 24
04/26  51/38/45/-6/0.42/0.0/000/00         51 NE  AERO 50 NE  RMY 50
04/27  39/35/37/-14/0.94/T/000/00          54 NE  AERO 52 NNE RMY 55
04/28  48/35/42/-10/0.00/0.0/159/19        28 N   AERO 27 N   RMY N/A
04/29  55/35/45/-7/0.00/0.0/656/78         24 ENE AERO 23 ENE RMY 22
04/30  52/42/47/-5/0.01/0.0/000/00         36 SE  AERO 32 SE  RMY N/A

DAILY RECORDS FOR APRIL 2020

4/13/2020
NEW PEAK GUST OF 79 MPH S, REPLACING THE OLD
RECORD OF 59 MPH SSW IN 1995

4/18/2020
NEW RECORD SNOWFALL OF 4.3 INS, REPLACING THE OLD
RECORD OF 3.7 INS IN 1965

4/27/2020
NEW RECORD LOW MAX TEMPERATURE OF 39F, REPLACING
THE OLD RECORD OF 40F IN 1917

PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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

05/01  64/52/58/+5/…./0.0/…/..         46 SSE  AERO 44 SSE RMY N/A
05/02  70/42/56/+3/…./0.0/…/..         41 NW   AERO 40 NW  RMY N/A
05/03  78/55/67/+14/0.00/0.0/…/..        35 SSW  AERO 35 SSW RMY 36
05/04  72/45/59/+5/T/0.0/…/..            37 NW   AERO 40 WNW RMY 39
05/05  60/40/50/-4/0.00/0.0/…/..         31 NW   AERO 32 NW  RMY N/A
05/06  57/38/48/-6/T/0.0/…/..            24 ESE  AERO 22 ENE RMY 22
05/07  63/37/50/-5/0.00/0.0/…/..         30 WSW  AERO 29 WSW RMY N/A
05/08  57/40/49/-6/…./0.0/…/..         31 W    AERO 32 W   RMY N/A
05/09  44/32/38/-17/…./T/…/..          52 W    AERO 53 W   RMY 54
05/10  59/31/45/-10/0.00/0.0/…/..        46 W    AERO 46 W   RMY 49
05/11  65/43/54/-2/0.22/0.0/…/..         39 S    AERO 43 S   RMY 41
05/12  55/37/46/-10/0.00/0.0/…/..        37 W    AERO 37 W   RMY 37

05/13 The low since midnight is 32F, the daily normal low is 47F

DAILY RECORDS FOR MAY 2020

5/13/2020: NEW RECORD LOW OF 32F, REPLACING 35F SET IN
1914 AND 2005

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

RECORDS FOR MAY 12
HIGH 88F IN 2001
LOW 29F IN 1907
PRECIP 1.49 INCHES IN 1968
PEAK GUST 76 MPH S IN 1974

RECORDS FOR MAY 13
HIGH 85F IN 1947
LOW 35F IN 1914, 2005
PRECIP 2.39 INCHES IN 2006
PEAK GUST 49 MPH NNW IN 1965

TODAY’S REPORT PREPARED BY: Benjamin Turner

Category: Daily Discussions

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