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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 8, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

A SUNNY START, BUT CLOUDS ON THE INCREASE...

We began the day with brilliant sunshine. As
the morning progressed, a high-altitude cloud
deck filtered in thus overtaking the sunshine.
Mid-level altostratus were then introduced by the 1 PM
observation - all an indication of an approaching
low pressure center. Dew points have remained in
the mid-teens to mid-20s despite the increasing
cloudiness. Thanks to this very dry air, visibility
has remained excellent between 80 and 85 miles
with southwestern New Hampshire in good view.

The high so far today is 57F, this is 7 degrees below
our daily normal high temperature of 64F. The  low
since midnight is 42F, which is 3 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: N/A

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: N/A
Astronomical total minutes: N/A

Today's Observations:

7 A.M.
Weather: Scattered Cirrostratus, Few Cumulus, Few Cirrus
Temperature: 45F; Dew Point: 26F; Relative Humidity: 47%
Wind: W at 17G24 kts  
Sea-level pressure: 29.81 ins. Hg: rising, then more slowly
Visibility: 80 miles
6-hr Max temp: 51F
6-hr Min temp: 42F
24-hr Precip: 0.00 ins
24-hr Snowfall: 0.0 ins.
BHO SA 1155 250 SCT 80 094/45/26/2717G24/981/ FEW CU SW AND W-N
SCT CS DSNT SSE-SW FEW CI E-SW/ 8/106 51021 10051 20042

10 A.M.
Weather: (thin) Broken Cirrostratus, Few Cumulus
Temperature: 51F; Dew Point: 19F; Relative Humidity: 27%
Wind: W at 14G23 kts
Peak Wind: 31 (27 kts) W @ 8:54 A.M.
Sea-level pressure: 29.81 ins. Hg: falling, then more slowly
Visibility: 85 miles 
3-hr Precip:  0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA1455 1455 E250 –BKN 85 096/51/19/2614G23/981/
FEW CU W-N PK WND 2627/1254/ 8/106 55002

1 P.M.
Weather: Broken Altostratus, (thin) Overcast Cirrostratus,
Few Cumulus
Temperature: 55F; Dew Point: 14F; Relative Humidity: 18%
Wind: WSW at 11G16 kts
Sea-level pressure: 29.74 ins. Hg: steady, then falling
Visibility: 80 miles 
6-hr Max temp: 57F
6-hr Min temp: 45F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 E150 BKN E250 –OVC 80 080/55/14/2411G16/974/
FEW CU W-N/ 8/126 58016 10057 20045

SUMMARY FOR THURSDAY, MAY 7, 2020 

TEMPERATURE (DEGREES F)
MAX.....63   NORMAL.....64
MIN.....37   NORMAL.....45
MEAN....50   NORMAL.....55

DEPARTURE FROM 30-YEAR NORMAL.................. -5
TOTAL DEPARTURE FOR THE MONTH..................+12 [+1.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............15  DEPARTURE....... +4
TOTAL HEATING UNITS FOR THE MONTH...............69  DEPARTURE.......-13
TOTAL HEATING UNITS FOR THE SEASON............5590  DEPARTURE......-527
TOTAL HEATING UNITS LAST SEASON TO DATE.......6005  DEPARTURE......-415

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....................30 WSW AT 11:31 P.M.  
                   AERO.........................29 WSW AT 11:35 P.M.  
                   ASOS.........................29 WSW AT 11:31 P.M. 
                   DAVIS........................30 WSW AT 11:30 P.M. RMY N/A
FASTEST MILE FOR YESTERDAY......................23 W   AT 11:43 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................22 W   AT 11:42 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................23 W   AT 11:42 P.M.
AVERAGE WIND SPEED AND DIRECTION................9.7 NW               
                   ASOS.........................10.8
                   DAVIS........................9.9 WNW [289 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..........0.94  DEPARTURE......+0.20
                         ASOS..............0.96
TOTAL PRECIPITATION FOR THE YEAR..........17.98  DEPARTURE......-1.31
                         ASOS.............18.56

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE........0.0
TOTAL SNOWFALL FOR THE MONTH................0.0  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/.../0.0/000/00           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

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 The low since midnight is 42F, the daily normal low is 45F
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):  

RECORDS FOR MAY 8
HIGH 89F IN 2000
LOW 29F IN 1956
PRECIP 1.48 INCHES IN 1886
SNOWFALL TRACE IN 1898, 1947
PEAK GUST 68e MPH NNW IN 1943

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

TODAY'S REPORT PREPARED BY: Andrew Swanson