Friday, May 1, 2020

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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 1, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

OVERCAST SKIES AND RAIN WELCOME US INTO MAY…

A beneficial overnight rain yielded 0.70 ins.
with another 0.14 ins. by the early afternoon.
Winds have relaxed quite a bit since peaking
around 3:45 AM this morning at 46 MPH. Only 10-
15 MPH gusts were felt by 1PM. Winds continue
to remain predominantly southerly since late
Wednesday evening.

Being socked in low clouds throughout the
morning, our max visibility only reached 1/2 mile,
but it quickly increased to 50 miles right before
the 1PM observation.

Temperature-wise, today has been notably milder
with a low so far of only 52F and a high of 59F.

Speaking of temperatures, as we wrap up the
month of April, it will go down in the books
as the first month since February 2015 with
at least 23 days below average. April 2020
will also be known for recording 16 consecutive
days of below average temps. The last time
this occurred was also in February 2015.
Precipitation? April was good for the 7th
wettest April dating back to 1885.

The high so far today is 59F, this is 2 degrees
below our daily normal high temperature of 61F.
The low since midnight is 52F, which is 9 degrees
above the daily normal low of 43F.

BHO Greatest April Precipitation, inches (1885-2020):

1) 10.37 in 1987
2) 9.38 in 2004
3) 8.71 in 1929
4) 8.68 in 2007
5) 8.53 in 1904
6) 8.14 in 2019
7) 7.70 in 2020 (through 7 AM EST on the 30th)
8) 7.57 in 1935
7.57 in 1983
10) 7.31 in 1901

Today’s Observations:

7 A.M.
Weather: Vertical visibility 300 ft, sky obscured, moderate rain
Temperature: 54F; Dew Point: 54F; Relative Humidity: 100%
Wind: SE at 20 kts
Peak Wind: 38 MPH (33 kts) S at 5:08 A.M.
Sea-level pressure: 29.80 ins. Hg: falling unsteadily
Visibility: 1/8 mile, fog
6-hr Max temp: 54F
6-hr Min temp: 52F
24-hr Precip: 0.70 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 X W3 1/8RF 091/54/54/1420/980/ RCTD PK WND 1733/1008/
8/// 57009 70070 10054 20052

10 A.M.
Weather: Vertical visibility 300 ft, sky obscured
Temperature: 54F; Dew Point: 54F; Relative Humidity: 100%
Wind: SSE at 13G28 kts
Peak Wind: 35 MPH (30 kts) SSE at 9:41 A.M.
Sea-level pressure: 29.70 ins. Hg: falling unsteadily
Visibility: 1/2 mile, fog
3-hr Precip:  0.14 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 X W3 1/2F 057/54/54/1513G28/970/ PK WND 1630/41/
8/// 6014 57034

1 P.M.
Weather: Overcast Stratus Fractus
Temperature: 58F; Dew Point: 55F; Relative Humidity: 90%
Wind: SW at 11 kts
Sea-level pressure: 29.66 ins. Hg: rising, then falling
Visibility: 50 miles (25 miles SE), distant fog
6-hr Max temp: 59F
6-hr Min temp: 54F
6-hr Precip:  0.14 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 E40 OVC 50 045/58/55/2211/966/ DSNT FG ALQDS
VSBY 25 SE/ 8/6// 6014 58012 10059 20054

SUMMARY FOR THURSDAY, APRIL 30, 2020

TEMPERATURE (DEGREES F)
MAX…..52   NORMAL…..61
MIN…..42   NORMAL…..43
MEAN….47   NORMAL…..52

DEPARTURE FROM 30-YEAR NORMAL……………….-5
TOTAL DEPARTURE FOR THE MONTH……………….-100 [-3.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………18  DEPARTURE……..+5
TOTAL HEATING UNITS FOR THE MONTH…………..648  DEPARTURE…….+97
TOTAL HEATING UNITS FOR THE SEASON…………5521  DEPARTURE……-514
TOTAL HEATING UNITS LAST SEASON TO DATE…….5900  DEPARTURE……-379

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..36 SE  AT  10:42 P.M.
AERO…………………….32 SE  AT  10:59 P.M.
ASOS…………………….31 SSE AT  10:42 P.M.
DAVIS……………………35 SE  AT  10:42 P.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….26 SE  AT  10:44 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….23 SE  AT  10:45 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………26 SE  AT  10:46 P.M.
AVERAGE WIND SPEED AND DIRECTION…………….12.8 SE
ASOS…………………….11.6
DAVIS……………………12.9 SE [143 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.70  DEPARTURE……+0.58
ASOS…………..0.67
TOTAL PRECIPITATION FOR THE MONTH……….7.70  DEPARTURE……+3.15
ASOS…………..7.87
TOTAL PRECIPITATION FOR THE YEAR……….17.03  DEPARTURE……-1.52
ASOS………….17.60

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE MONTH…………….4.3  DEPARTURE…….+1.3
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/…/0.0/000/00           39 NW  AER0 40 NW  RMY 41
04/03  42/38/40/-2/…./0.0/000/00         48 NE  AERO 53 NE  RMY 49
04/04  46/36/41/-1/…./0.0/278/36         38 NE  AERO 38 NE  RMY N/A
04/05  55/36/46/+3/T/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/…./…/047/06         23 S   AERO 22 S   RMY 22
04/09  47/37/42/-2/…./…/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/…./0.0/591/73         41 W   AERO 39 W   RMY 41
04/18  37/31/34/-14/…./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/…/..         25 ENE AERO 22 W   RMY N/A
04/21  53/33/43/-6/…./…/…/..         52 S   AERO 52 S   RMY 52
04/22  43/30/37/-12/0.00/0.0/…/..        51 W   AERO 50 W   RMY 50
04/23  55/29/42/-8/0.00/0.0/…/..         31 W   AERO 29 W   RMY N/A
04/24  42/37/40/-10/…./…/…/..        31 NNE AERO 29 NNE RMY 29
04/25  60/38/49/-1/0.00/0.0/…/..         25 S   AERO 24 S   RMY 24
04/26  51/38/45/-6/…./0.0/…/..         51 NE  AERO 50 NE  RMY 50
04/27  39/35/37/-14/…./T/…/..          54 NE  AERO 52 NNE RMY 55
04/28  48/35/42/-10/…./…/…/..        28 N   AERO 27 N   RMY N/A
04/29  55/35/45/-7/0.00/0.0/…/..         24 ENE AERO 23 ENE RMY 22
04/30  52/42/47/-5/…/0.0/…/..          36 SE  AERO 32 SE  RMY N/A

05/01 The low since midnight is 52F, daily normal minimum is 43F

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

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

RECORDS FOR MAY 1
HIGH 87F IN 1899
LOW 29F IN 1978
PRECIP 2.53 INCHES IN 1921
SNOWFALL TRACE IN 1905,1917,1921,1995,2016
PEAK GUST 57 MPH NW IN 1974

RECORDS FOR MAY 2
HIGH 92F IN 2001
LOW 29F IN 1903
PRECIP 1.36 INCHES IN 2006
SNOWFALL 1.0 INS IN 1888
PEAK GUST 58 MPH S IN 1983

TODAY’S REPORT PREPARED BY: Andrew Swanson