BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, DECEMBER 24, 2019 ALL TIMES ARE IN EASTERN STANDARD TIME A FAIR WEATHER DAY WITH A COOL NORTHERLY BREEZE.... Today we observed partly cloudy skies with abundant sunshine. Visibility was excellent at 80 miles on average, with 85 miles being seen at 10 A.M. and 1 P.M. Wind was consistent at a speed of 10 mph from the north. Humidity dropped to 40% by the 1 P.M. observation.   The high so far today is 42F, which is 6 degrees above the daily normal maximum of 36F. The low since midnight is 33F, which is 12 degrees above the normal minimum of 21F. Today's Observations: 7 A.M. Weather: Scattered cirrus Temperature: 34F; Dew Point: 23F; Wind: NW at 13G16 kts Sea-level pressure: 30.06 ins. Hg, rising steadily Visibility: 75 miles 6-hr Max temp: 42F 6-hr Min temp: 34F 24-hr Precip:  0.00 ins. 24-hr Snowfall: 0.0 ins. Snow Depth: Trace BHO SA 1155 250 SCT 75 171/34/23/3213G18/006/ 8/002 53031 10042 20034 10 A.M. Weather: Broken cirrus Temperature: 36F; Dew Point: 20F; Wind: NNW at 11G18 kts, Sea-level pressure: 30.15 ins. Hg, rising steadily Visibility: 85 miles 3-hr Precip:  0.00 ins. 3-hr Snowfall: 0.0 ins. BHO SA 1455 E250 BKN 85 200/36/20/3311G18/015/ 8/002 53029 1 P.M. Weather: Scattered cirrus Temperature: 42F; Dew Point: 19F; Wind: N at 8 kts Sea-level pressure: 30.12 ins. Hg, falling steadily Visibility: 85 miles 6-hr Max temp: 42F 6-hr Min temp: 33F 6-hr Precip:  0.00 ins. 6-hr Snowfall: 0.0 ins. Snow Depth: Trace BHO SA 1755 250 SCT 85 190/42/19/3508/012/ 8/002 56010 10042 20033 SUMMARY FOR MONDAY, DECEMBER 23, 2019 TEMPERATURE (DEGREES F) MAX.....54   NORMAL.....37 MIN.....33   NORMAL.....21 MEAN....44   NORMAL.....29 DEPARTURE FROM 30-YEAR NORMAL.....................+15 TOTAL DEPARTURE FOR THE MONTH.....................-38 [-1.9 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY...............21  DEPARTURE.......-15 TOTAL HEATING UNITS FOR THE MONTH..............781  DEPARTURE.......+36 TOTAL HEATING UNITS FOR THE SEASON............2018  DEPARTURE.......+11 TOTAL HEATING UNITS LAST SEASON TO DATE.......2041  DEPARTURE.......-23 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY....................30 WSW AT  8:47 P.M.                      AERO.........................30 SW  AT  6:08 P.M.                      ASOS.........................31 W   AT  8:48 P.M.                    DAVIS........................32 SW  AT  7:35 P.M. RMY 30 FASTEST MILE FOR YESTERDAY......................25 SW  AT  5:52 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...................22 W   AT  8:57 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..................24 W   AT  8:55 P.M. AVERAGE WIND SPEED AND DIRECTION..............14.1 WSW                                      ASOS.......................13.9                    DAVIS......................13.9 WSW  [243 deg.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.16                          ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........6.06  DEPARTURE......+2.35                          ASOS..............6.51 TOTAL PRECIPITATION FOR THE YEAR..........55.14  DEPARTURE......+2.89                          ASOS.............55.91 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.......-0.5 TOTAL SNOWFALL FOR THE MONTH...............19.1  DEPARTURE.......+9.9 TOTAL SNOWFALL FOR THE SEASON..............19.2  DEPARTURE.......+7.4 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 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 12/01  32/16/24/-13/..../5.8/011/02           33 ENE AERO 32 ENE RMY N/A 12/02  37/25/31/-5/..../2.7/000/00            52 NE  AERO 47 NE  RMY 53 12/03  30/23/27/-9/..../4.6/000/00            32 N   AERO 35 N   RMY 36 12/04  34/22/28/-7/..../0.0/000/00            23 WNW AERO 23 NNW RMY N/A 12/05  41/26/34/-1/..../0.0/343/62            33 NW  AERO 35 NW  RMY 37 12/06  33/23/28/-7/0.02/0.1/000/00            25 NW  AERO 23 NW  RMY 29 12/07  31/18/25/-9/0.00/0.0/519/94            25 NW  AERO 23 NW  RMY N/A 12/08  36/15/26/-8/0.00/0.0/.../..            31 SSW AERO 32 SSW RMY N/A 12/09  57/36/47/+13/..../0.0/.../..           53 S   AERO 52 S   RMY 54 12/10  58/37/48/+15/..../0.0/.../..           35 SW  AERO 39 SW  RMY N/A 12/11  36/23/30/-3/..../3.0/.../..            25 NW  AERO 25 NW  RMY N/A 12/12  29/17/23/-10/..../1.8/.../..           29 W   AERO 30 W   RMY 25 12/13  46/22/34/+2/..../0.0/.../..            25 SSE AERO 25 SSE RMY N/A 12/14  58/46/52/+20/..../0.0/.../..           45 S   AERO 41 S   RMY N/A 12/15  48/28/38/+6/0.00/0.0/.../..            53 W   AERO 53 W   RMY 50 12/16  30/25/28/-3/0.00/0.0/.../..            36 W   AERO 36 W   RMY N/A 12/17  35/23/29/-2/..../1.0/.../..            22 NNW AERO 21 NE  RMY 23 12/18  33/18/26/-5/.../0.0/.../..             44 WNW AERO 45 WNW RMY N/A 12/19  20/9/15/-15/.../0.0/.../..             51 W   AERO 47 W   RMY N/A 12/20  29/11/20/-10/0.00/0.0/..../..          32 W   AERO 30 W   RMY 29 12/21  31/16/24/-6/0.00/0.0/..../..           16 SSE AERO 15 SSE RMY N/A 12/22  40/26/33/+4/0.00/0.0/..../..           23 SW  AERO 21 SW  RMY 23 12/23  54/33/44/+15/0.00/0.0/..../..          30 WSW AERO 30 SW  RMY 30 12/24 The low since midnight is 33F, daily normal minimum is 21F DAILY RECORDS FOR DECEMBER 12/01/19: DAILY RECORD SNOWFALL OF 5.8 INS.,           BREAKS PREVIOUS RECORD OF 2.0 INS. SET IN 1902. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated):   RECORDS FOR DECEMBER 24 HIGH 67 IN 2015 LOW -6 IN 1943 PRECIP 2.21 INS. IN 1994 SNOWFALL 12.3 INS. IN 1961 PEAK GUST 79e MPH SE IN 1941 RECORDS FOR DECEMBER 25 HIGH 64 IN 2015 LOW -11 IN 1980 PRECIP 1.37 INS. IN 2002 SNOWFALL 8.5 INS. IN 2002 PEAK GUST 80 MPH NW IN 1971 TODAY'S REPORT PREPARED BY: Benjamin Turner