BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 9, 2020 ALL TIMES ARE IN EASTERN STANDARD TIME LIGHT SNOW IN THE MORNING LEADS TO A PARTLY CLOUDY AFTERNOON... Today began with some light snow in the morning hours following some rainfall overnight. This totaled 0.45 inches, and a light snow began shortly before the 7 A.M. observation. The snowfall left only a trace, ending before 9 A.M. After that, clouds decreased with a steady rise in pressure. With this rise in pressure, wind was strong today, with an average speed of almost 30 mph. The max gust exceeded 50 mph. Visibility is excellent between 80 and 85 miles with Mount Monadnock in good view. This was after this morning where visibility was only 3 miles due to fog. Strong cold air advection from the west kept temperatures well below seasonal averages. The high so far today is 44F, which is 20 degrees below our daily normal high temperature of 64F. The low since midnight is 33F, which is 12 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: 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: Overcast stratus, light snow Temperature: 34F; Dew Point: 31F; Relative Humidity: 88% Wind: WNW at 15G26 kts, peak of 36 mph at 6:41 A.M.   Sea-level pressure: 29.50 ins. Hg: rising steadily Visibility: 3 miles, fog 6-hr Max temp: 40F 6-hr Min temp: 34F 24-hr Precip:   0.45 ins. 24-hr Snowfall: Trace BHO SA 1155 E40 OVC 3F 989/34/31/2915G26/950/ PK WND 2931/41 S-B55 NEW SNW PST 24 HRS TRACE/ 8/6// 70045 53019 10040 20034 10 A.M. Weather: Broken stratocumulus Temperature: 38F; Dew Point: 27F; Relative Humidity: 77% Wind: WNW at 25G42 kts, peak of 50 mph at 9:38 A.M. Sea-level pressure: 29.57 ins. Hg: rising steadily Visibility: 80 miles 3-hr Precip:   Trace 3-hr Snowfall: Trace BHO SA 1455 E40 BKN 80 014/38/27/3025G42/957/ PK WND 2841/38 NEW SNW PST 3 HRS TRACE/ 8/800 600// 51025 1 P.M. Weather: Broken stratocumulus Temperature: 42F; Dew Point: 18F; Relative Humidity: 37% Wind: W at 30G42 kts, peak of 51 mph at 12:44 P.M. Sea-level pressure: 29.63 ins. Hg: rising steadily Visibility: 80 miles 6-hr Max temp: 44F 6-hr Min temp: 33F 6-hr Precip:   Trace 6-hr Snowfall: Trace BHO SA 1755 E50 BKN 80 035/42/18/2830G42/963/ PK WND 2842/44 NEW SNW PST 6 HRS TRACE/ 8/800 600// 51021 10044 20033 SUMMARY FOR FRIDAY, MAY 8, 2020 TEMPERATURE (DEGREES F) MAX.....57   NORMAL.....64 MIN.....40   NORMAL.....45 MEAN....49   NORMAL.....55 DEPARTURE FROM 30-YEAR NORMAL.................. -6 TOTAL DEPARTURE FOR THE MONTH.................. +6 [+0.6 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY...............16  DEPARTURE.......+6 TOTAL HEATING UNITS FOR THE MONTH...............85  DEPARTURE.......-8 TOTAL HEATING UNITS FOR THE SEASON............5606  DEPARTURE......-521 TOTAL HEATING UNITS LAST SEASON TO DATE.......6012  DEPARTURE......-406 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....................31 W   AT  7:53 A.M.                      AERO.........................32 W   AT  7:53 A.M.                     ASOS.........................31 W   AT  7:53 A.M.                    DAVIS........................32 W   AT  7:53 A.M. RMY N/A FASTEST MILE FOR YESTERDAY......................24 W   AT  7:53 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE...................24 W   AT  7:55 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..................25 W   AT  7:55 A.M. AVERAGE WIND SPEED AND DIRECTION................11.3 W                                  ASOS.........................11.0                    DAVIS........................11.5 W [260 deg.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.45  DEPARTURE......+0.32                          ASOS..............0.43 TOTAL PRECIPITATION FOR THE MONTH..........1.39  DEPARTURE......+0.52                          ASOS..............1.39 TOTAL PRECIPITATION FOR THE YEAR..........18.43  DEPARTURE......-0.99                          ASOS.............18.99 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M........Trace  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/.../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/.../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/-5/0/0.0/.../..            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 The low since midnight is 34F, the daily normal low is 46F   DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated):   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 RECORDS FOR MAY 10 HIGH 93F IN 1896 LOW 29F  IN 1900 PRE 1.85 INS IN 1998 SNOW 2.8 INS 1977 (7.8 INS TOTAL 5/9-5/10 1977) PEAK GUST 64 MPH S IN 1990 TODAY'S REPORT PREPARED BY: Andrew Swanson