BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, MAY 21, 2020 ALL TIMES ARE IN EASTERN STANDARD TIME DRY WITH LOW HUMIDITY AND A LIGHT WIND ATOP GREAT BLUE HILL.... We observed almost clear conditions this morning, with some extra clouds in the afternoon with a steady pressure fall. Visibility was great at 75 miles on average, with the best of 80 being seen at the 7 A.M. observation. Today was warm, with some light warm air advection from the southwest. Despite an average speed below 10 mph, the peak gust so far today has reached 20 mph. Humidity is very low, reaching 18% following the 1 P.M. observation. The high so far today is 74F, this is 6 degrees above the daily normal high of 68F. The low since midnight is 42F, which is 7 degrees below the daily normal low of 49F. Today's Observations: 7 A.M. Weather: Few cirrus Temperature: 50F; Dew Point: 34F; Relative Humidity: 54% Wind: WSW at 7 kts   Sea-level pressure: 30.42 ins. Hg: steady, then rising Visibility: 80 miles 6-hr Max temp: 50F 6-hr Min temp: 42F 24-hr Precip:  0.00 ins. 24-hr Snowfall: 0.0 ins. BHO SA 1155 CLR 80 303/50/34/2507/042/ FEW CI ALQDS/ 8/002 52004 10050 20042 10 A.M. Weather: Few cirrus Temperature: 65F; Dew Point: 25F; Relative Humidity: 21% Wind: SSW at 6 kts, light Sea-level pressure: 30.39 ins. Hg: falling, then more slowly Visibility: 70 miles 3-hr Precip:  0.00 ins. 3-hr Snowfall: 0.0 ins. BHO SA 1455 CLR 70 293/65/25/2106/039/ FEW CI ALQDS WND LGT/ 8/002 58010 1 P.M. Weather: Broken cirrus Temperature: 74F; Dew Point: 30F; Relative Humidity: 19% Wind: SSW at 7 kts Sea-level pressure: 30.33 ins. Hg: falling steadily Visibility: 80 miles 6-hr Max temp: 74F 6-hr Min temp: 50F 6-hr Precip:  0.00 ins. 6-hr Snowfall: 0.0 ins. BHO SA 1755 E250 BKN 80 273/74/30/2107/033/ 8/002 58020 10074 20050 SUMMARY FOR WEDNESDAY, MAY 20, 2020 TEMPERATURE (DEGREES F) MAX.....63   NORMAL.....68 MIN.....43   NORMAL.....48 MEAN....53   NORMAL.....58 DEPARTURE FROM 30-YEAR NORMAL...................-5 TOTAL DEPARTURE FOR THE MONTH..................-53 [-2.9 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY...............12  DEPARTURE........+5 TOTAL HEATING UNITS FOR THE MONTH..............244  DEPARTURE.......+44 TOTAL HEATING UNITS FOR THE SEASON............5765  DEPARTURE......-470 TOTAL HEATING UNITS LAST SEASON TO DATE.......6149  DEPARTURE......-384 COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY................0  DEPARTURE........-1 TOTAL COOLING UNITS FOR THE MONTH................2  DEPARTURE........-7 TOTAL COOLING UNITS FOR THE SEASON...............2  DEPARTURE........-9 TOTAL COOLING UNITS LAST SEASON TO DATE..........4  DEPARTURE........-2 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY....................22 ESE AT  1:42 P.M.                      AERO.........................20 SE  AT  6:42 P.M.                     ASOS.........................18 S   AT 10:16 P.M.                    DAVIS........................19 E   AT  1:41 P.M. RMY 19 FASTEST MILE FOR YESTERDAY......................13 SSE AT  9:32 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...................14 S   AT 10:16 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..................14 SSE AT  9:28 P.M. AVERAGE WIND SPEED AND DIRECTION................7.9 ENE                                  ASOS.........................8.1                    DAVIS........................8.5 ESE [107 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..........2.55  DEPARTURE......+0.07                          ASOS..............2.54 TOTAL PRECIPITATION FOR THE YEAR..........19.59  DEPARTURE......-1.44                          ASOS.............20.04 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 The low since midnight is 42F, the daily normal low is 49F   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 21 HIGH 92F IN 1921 LOW 35F IN 1907 PRECIP 1.61 INS IN 1954 PEAK GUST 74 MPH WSW IN 2006 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 TODAY'S REPORT PREPARED BY: Benjamin Turner