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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 15, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

A CHANGEABLE WEATHER DAY HERE ATOP GREAT BLUE HILL...

Today began with a visibility of 1/16 mile in
thick fog. As the morning progressed, the ceiling
lifted allowing visibility to increase to 45 miles
and skies to become scattered.  Winds have been on
the lighter side with gusts capping out so far at
only 18 MPH. Overnight rain amounted to 0.06 ins. 

It has been noticeably more humid with dew points
topping out at 57F so far - a big difference from
yesterday when dew points in the teens were recorded.

The high so far today is 75F, this is 9 degrees above the 
daily normal high of 66F. The low since midnight is 50F,
which is 2 degrees above the daily normal low of 48F.


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: Vertical visibility 100 ft, sky obscured
Temperature: 51F; Dew Point: 51F; Relative Humidity: 100%
Wind: S at 8 kts  
Sea-level pressure: 29.98 ins. Hg: steady, then falling
Visibility: 1/16 miles, fog
6-hr Max temp: 54F
6-hr Min temp: 50F
24-hr Precip:  0.06 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 X W1 1/16F 153/51/51/1808/998/ 8////
58004 70006 10054 20050

10 A.M.
Weather: Scattered Cumulus & Stratocumulus; Scattered Cirrus
Temperature: 60F; Dew Point: 55F; Relative Humidity: 82%
Wind: SW at 8 kts
Sea-level pressure: 29.96 ins. Hg: steady, then falling
Visibility: 35 miles, distant fog
3-hr Precip:  0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 15 SCT 250 SCT 35 146/60/55/2208/996/
DSNT FG ALQDS/ 8/802 58007

1 P.M.
Weather: Broken Cumulus
Temperature: 74F; Dew Point: 55F; Relative Humidity: 56%
Wind: SW at 9 kts
Sea-level pressure: 29.91 ins. Hg: falling, then more rapidly
Visibility: 45 miles, hazy
6-hr Max temp: 75F
6-hr Min temp: 51F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 BKN 30 45 129/74/55/2309/991/ HAZY/ 8/100 58017
10075 20051

SUMMARY FOR THURSDAY, MAY 14, 2020 

TEMPERATURE (DEGREES F)
MAX.....70   NORMAL.....66
MIN.....40   NORMAL.....47
MEAN....55   NORMAL.....57

DEPARTURE FROM 30-YEAR NORMAL...................-2
TOTAL DEPARTURE FOR THE MONTH..................-45 [-3.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............10  DEPARTURE........+1
TOTAL HEATING UNITS FOR THE MONTH..............191  DEPARTURE.......+40
TOTAL HEATING UNITS FOR THE SEASON............5712  DEPARTURE......-474
TOTAL HEATING UNITS LAST SEASON TO DATE.......6108  DEPARTURE......-396

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY................0  DEPARTURE........-1
TOTAL COOLING UNITS FOR THE MONTH................2  DEPARTURE........-3
TOTAL COOLING UNITS FOR THE SEASON...............2  DEPARTURE........-5
TOTAL COOLING UNITS LAST SEASON TO DATE..........0  DEPARTURE........+2

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................29 W AT 3:13 P.M.  
                   AERO.........................26 W AT 3:13 P.M.  
                   ASOS.........................27 W AT 3:14 P.M. 
                   DAVIS........................29 W AT 3:13 P.M. RMY 27
FASTEST MILE FOR YESTERDAY......................22 W AT 3:15 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................22 W AT 3:15 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................23 W AT 3:15 P.M.
AVERAGE WIND SPEED AND DIRECTION................11.0 W               
                   ASOS.........................10.8
                   DAVIS........................11.2 WSW [253 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.06  DEPARTURE......-0.06
                         ASOS..............0.06
TOTAL PRECIPITATION FOR THE MONTH..........1.67  DEPARTURE......-0.04
                         ASOS..............1.66
TOTAL PRECIPITATION FOR THE YEAR..........18.71  DEPARTURE......-1.55
                         ASOS.............19.26

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  59/32/46/-10/0.00/0.0/.../..        37 WNW  AERO 37 WNW RMY 38
05/14  70/40/55/-2/0.00/0.0/.../..         29 W    AERO 26 W   RMY 27

05/15 The low since midnight is 50F, the daily normal low is 48F
 
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 15
HIGH 93F IN 1900
LOW 36F IN 1947,1985
PRECIP 1.63 INCHES IN 1978
PEAK GUST 53e MPH NE IN 1978, W 2002

RECORDS FOR MAY 16
HIGH 90F IN 1951
LOW 30F IN 1936
PRECIP 2.63 INCHES IN 1954
PEAK GUST 56e MPH NW IN 1952

TODAY'S REPORT PREPARED BY: Andrew Swanson