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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 22, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

ANOTHER DAY WITH COMFORTABLE HUMIDITY, LIGHT
WINDS, AND ABUNDANT SUNSHINE ATOP GREAT BLUE
HILL....

Today has been a near carbon copy of yesterday,
albeit a little warmer and a little more wind. 
We observed mainly clear conditions this morning
minus a few decorative cirrus clouds to our northeast.
Visibility was limited to 35 miles with haze at 7AM
decreasing  to 30 miles by the 1PM observation. With
the lack of any rainfall recently, pollen is largely
to blame for the limited visibility rather than the
humidity which is in the mid-30s (%). Peak wind
speed so far is 29 MPH.

We continued with the warm air advection from the
southwest and west-southwest today boosting temperatures
into the lower-80s. That makes the first 80-degree
reading since September 23rd, 2019!

The high so far today is 80F, this is 12 degrees above the 
daily normal high of 68F. The low since midnight is 50F,
which is equal to the daily normal low of 50F.


Today's Observations:

7 A.M.
Weather: Clear; few cirrus (north to east)
Temperature: 61F; Dew Point: 51F; Relative Humidity: 68%
Wind: W at  11G17kts   
Sea-level pressure: 30.16 ins. Hg: falling unsteadily
Visibility: 35 miles, hazy
6-hr Max temp: 61F
6-hr Min temp: 51F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 CLR 35 215/61/51/2611G17/016/ FEW CI N-E HAZY/
8/001 57002 10061 20051

10 A.M.
Weather: Clear; few cumulus (southeast to southwest)
Temperature: 74F; Dew Point: 50F; Relative Humidity: 43%
Wind: WSW at 10G16kts
Sea-level pressure: 30.13 ins. Hg: falling, then more rapidly
Visibility: 35 miles, hazy
3-hr Precip:  0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 CLR 35 203/74/50/2510G16/013/ FEW CU SE-SW HAZY/
8/100 58012 

1 P.M.
Weather: Clear; few cumulus (southeast to southwest)
Temperature: 79F; Dew Point: 51F; Relative Humidity: 38%
Wind: SW at 11G25 kts
Sea-level pressure: 30.06 ins. Hg: falling, then more rapidly
Visibility: 30 miles, hazy
6-hr Max temp: 80F
6-hr Min temp: 61F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
BHO SA 1755 CLR 30 178/79/51/2311G25/006/ FEW CU SE-SW HAZY/
8/100 58025 10080 20061

SUMMARY FOR THURSDAY, MAY 21, 2020 

TEMPERATURE (DEGREES F)
MAX.....76   NORMAL.....68
MIN.....42   NORMAL.....49
MEAN....59   NORMAL.....59

DEPARTURE FROM 30-YEAR NORMAL..................+/-0
TOTAL DEPARTURE FOR THE MONTH..................-53 [-2.7 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY................6  DEPARTURE........-1
TOTAL HEATING UNITS FOR THE MONTH..............250  DEPARTURE.......+42
TOTAL HEATING UNITS FOR THE SEASON............5771  DEPARTURE......-471
TOTAL HEATING UNITS LAST SEASON TO DATE.......6143  DEPARTURE......-382

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY................0  DEPARTURE........-1
TOTAL COOLING UNITS FOR THE MONTH................2  DEPARTURE........-8
TOTAL COOLING UNITS FOR THE SEASON...............2  DEPARTURE.......-10
TOTAL COOLING UNITS LAST SEASON TO DATE..........4  DEPARTURE........-2

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................26 S  AT 5:10 P.M.  
                   AERO.........................25 S  AT 6:33 P.M.  
                   ASOS.........................26 S  AT 3:22 P.M. 
                   DAVIS........................28 S  AT 6:39 P.M. RMY 25
FASTEST MILE FOR YESTERDAY......................20 S  AT 6:32 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................20 S  AT 6:32 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................19 SW AT 5:11 P.M.
AVERAGE WIND SPEED AND DIRECTION................11.8 SSW               
                   ASOS.........................12.1
                   DAVIS........................11.5 SW [222 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.14
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.55  DEPARTURE......-0.06
                         ASOS..............2.54
TOTAL PRECIPITATION FOR THE YEAR..........19.59  DEPARTURE......-1.57
                         ASOS.............20.14

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 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/..../0.0/000/00         46 SSE  AERO 44 SSE RMY N/A 
05/02  70/42/56/+3/..../0.0/729/86         41 NW   AERO 40 NW  RMY N/A
05/03  78/55/67/+14/0.00/0.0/613/72        35 SSW  AERO 35 SSW RMY 36
05/04  72/45/59/+5/T/0.0/247/29            37 NW   AERO 40 WNW RMY 39  
05/05  60/40/50/-4/0.00/0.0/821/96         31 NW   AERO 32 NW  RMY N/A
05/06  57/38/48/-6/T/0.0/498/58            24 ESE  AERO 22 ENE RMY 22
05/07  63/37/50/-5/0.00/0.0/576/67         30 WSW  AERO 29 WSW RMY N/A
05/08  57/40/49/-6/..../0.0/328/38         31 W    AERO 32 W   RMY N/A
05/09  44/32/38/-17/..../T/484/56          52 W    AERO 53 W   RMY 54
05/10  59/31/45/-10/0.00/0.0/763/88        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  78/50/64/+7/..../0.0/.../..         40 WSW  AERO 40 WSW RMY 43
05/16  69/47/58/+1/..../0.0/.../..         31 NW   AERO 31 NW  RMY 32
05/17  67/47/57/0/0.00/0.0/.../..          22 SSW  AERO N/A    RMY 21
05/18  60/47/54/-4/T/0.0/.../..            24 W    AERO 22 ENE RMY N/A
05/19  56/45/51/-7/0.00/0.0/.../..         35 ENE  AERO 34 ENE RMY 32
05/20  63/43/53/-5/0.00/0.0/.../..         22 ESE  AERO 20 SE  RMY 19
05/21 76/42/59/0/0.00/0.0/.../..           26 S    AERO 25 S   RMY 25

05/22 The low since midnight is 50F, the daily normal low is 50F
 
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 22
HIGH 93F IN 1911
LOW 35F IN 1907
PRECIP 3.75 INCHES IN 1920
PEAK GUST 49e MPH SSW IN 1947

RECORDS FOR MAY 23
HIGH 92F IN 1964,1992
LOW 38F IN 1976
PRECIP 0.97 INS IN 1979
PEAK GUST 49e MPH W IN 1945

TODAY'S REPORT PREPARED BY: Andrew Swanson