Saturday, May 9, 2020

| May 9, 2020 | Reply

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 9, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

LIGHT SNOW IN THE MORNING LEADS TO A PARTLY
CLOUDY AFTERNOON…

Today began with some light snow in the morning
hours following some rainfall overnight. This
totaled 0.45 inches, and a light snow began
shortly before the 7 A.M. observation. The
snowfall left only a trace, ending before 9 A.M.
After that, clouds decreased with a steady rise
in pressure. With this rise in pressure, wind
was strong today, with an average speed of
almost 30 mph. The max gust exceeded 50 mph.
Visibility is excellent between 80 and 85 miles
with Mount Monadnock in good view. This was after
this morning where visibility was only 3 miles due
to fog.

Strong cold air advection from the west kept temperatures
well below seasonal averages. The high so far today is 44F,
which is 20 degrees below our daily normal high temperature
of 64F. The low since midnight is 33F, which is 12 degrees
below the daily normal low of 45F.

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: N/A

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: Overcast stratus, light snow
Temperature: 34F; Dew Point: 31F; Relative Humidity: 88%
Wind: WNW at 15G26 kts, peak of 36 mph at 6:41 A.M.
Sea-level pressure: 29.50 ins. Hg: rising steadily
Visibility: 3 miles, fog
6-hr Max temp: 40F
6-hr Min temp: 34F
24-hr Precip:   0.45 ins.
24-hr Snowfall: Trace
BHO SA 1155 E40 OVC 3F 989/34/31/2915G26/950/ PK WND 2931/41
S-B55 NEW SNW PST 24 HRS TRACE/ 8/6// 70045 53019 10040 20034

10 A.M.
Weather: Broken stratocumulus
Temperature: 38F; Dew Point: 27F; Relative Humidity: 77%
Wind: WNW at 25G42 kts, peak of 50 mph at 9:38 A.M.
Sea-level pressure: 29.57 ins. Hg: rising steadily
Visibility: 80 miles
3-hr Precip:   Trace
3-hr Snowfall: Trace
BHO SA 1455 E40 BKN 80 014/38/27/3025G42/957/ PK WND 2841/38
NEW SNW PST 3 HRS TRACE/ 8/800 600// 51025

1 P.M.
Weather: Broken stratocumulus
Temperature: 42F; Dew Point: 18F; Relative Humidity: 37%
Wind: W at 30G42 kts, peak of 51 mph at 12:44 P.M.
Sea-level pressure: 29.63 ins. Hg: rising steadily
Visibility: 80 miles
6-hr Max temp: 44F
6-hr Min temp: 33F
6-hr Precip:   Trace
6-hr Snowfall: Trace
BHO SA 1755 E50 BKN 80 035/42/18/2830G42/963/ PK WND
2842/44 NEW SNW PST 6 HRS TRACE/ 8/800 600// 51021 10044 20033

SUMMARY FOR FRIDAY, MAY 8, 2020

TEMPERATURE (DEGREES F)
MAX…..57   NORMAL…..64
MIN…..40   NORMAL…..45
MEAN….49   NORMAL…..55

DEPARTURE FROM 30-YEAR NORMAL……………… -6
TOTAL DEPARTURE FOR THE MONTH……………… +6 [+0.6 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………16  DEPARTURE…….+6
TOTAL HEATING UNITS FOR THE MONTH……………85  DEPARTURE…….-8
TOTAL HEATING UNITS FOR THE SEASON…………5606  DEPARTURE……-521
TOTAL HEATING UNITS LAST SEASON TO DATE…….6012  DEPARTURE……-406

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………….0  DEPARTURE…….. 0
TOTAL COOLING UNITS FOR THE MONTH…………….2  DEPARTURE……..+1
TOTAL COOLING UNITS FOR THE SEASON……………2  DEPARTURE……..-2
TOTAL COOLING UNITS LAST SEASON TO DATE……….0  DEPARTURE……..+2

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..31 W   AT  7:53 A.M.
AERO…………………….32 W   AT  7:53 A.M.
ASOS…………………….31 W   AT  7:53 A.M.
DAVIS……………………32 W   AT  7:53 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….24 W   AT  7:53 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….24 W   AT  7:55 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………25 W   AT  7:55 A.M.
AVERAGE WIND SPEED AND DIRECTION…………….11.3 W
ASOS…………………….11.0
DAVIS……………………11.5 W [260 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.45  DEPARTURE……+0.32
ASOS…………..0.43
TOTAL PRECIPITATION FOR THE MONTH……….1.39  DEPARTURE……+0.52
ASOS…………..1.39
TOTAL PRECIPITATION FOR THE YEAR……….18.43  DEPARTURE……-0.99
ASOS………….18.99

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……..Trace  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/…/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/…/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/-5/0/0.0/…/..            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 The low since midnight is 34F, the daily normal low is 46F

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

RECORDS FOR MAY 9
HIGH 93F IN 2000
LOW 31F IN 1947
PRECIP 2.72 INCHES IN 1954
SNOWFALL 5.0 INS IN 1977 (RECORD FOR MAY)
PEAK GUST 70e MPH NE IN 1977

RECORDS FOR MAY 10
HIGH 93F IN 1896
LOW 29F  IN 1900
PRE 1.85 INS IN 1998
SNOW 2.8 INS 1977 (7.8 INS TOTAL 5/9-5/10 1977)
PEAK GUST 64 MPH S IN 1990

TODAY’S REPORT PREPARED BY: Andrew Swanson

Category: Daily Discussions

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