BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, DECEMBER 17, 2016 WARM FRONT BRINGS 4 IN OF SNOW TO SUMMIT, CHANGES TO LIGHT DRIZZLE BEFORE NOON Snow began early this morning and measured a total of 4.3 inches before turning to light rain by noon and then light drizzle. Total precipiation measured 0.58 in. at 1:00PM. Visibility was limted to less than 2 miles all day by fog. Temperatures had warmed to a max. of 33F, and winds became light and variable by the 1:00PM ob. 7 A.M. Weather: Light snow, fog, overcast stratus Temperature: 22F; Dew Point: 20F; Wind: ESE at 7 kts Sea-level pressure: 30.22 ins. Hg, falling, then less quickly Visibility: 1 1/2 miles 6-hr Max temp: 22F 6-hr Min temp: 19F 24-hr precip: 0.14 in. 2-hr snowfall: 1.7 in. BHO SA 1155 E12 OVC 1 1/2S-F 234/22/20/1207/022/ NEW SNW PST 24 HRS 1.7 INS/ 8/6// 4/002 56044 MANUAL 70014 ASOS 70014 10022 20019 10 A.M. Weather: Light snow, fog, overcast stratus Temperature: 27F; Dew Point: 25F; Wind: ESE at 14 kts Sea-level pressure: 30.07 ins. Hg, falling, then more quickly Visibility: 1/2 mile 3-hr precip: 0.16 in. 3-hr snowfall: 1.3 in. BHO SA 1455 E5 OVC 1/2S-F 184/27/25/1114/007/ NEW SNW PST 3 HRS 1.3 INS/ 8/6// MANUAL 6016/ ASOS 60015 58050 1 P.M. Weather: Light drizzle, thick fog Temperature: 32; Dew Point: 31F; Wind: E at 5 kts, Wind: Light and variable Sea-level pressure: 29.89 ins. Hg, falling, then more quickly Visibility: 1/8 mile 6-hr Max temp: 33F 6-hr Min temp: 22F 6-hr precip: 0.44 in. 6-hr snowfall: 2.6 in. BHO SA 1755 W3 X 1/8L-F 121/32/31/1005/989/ WND L/V NEW SNW PST 3 HRS 1.3 INS/ 8//// 56063 MANUAL 6044/ ASOS 60043 10033 20022 SUMMARY FOR FRIDAY, DECEMBER 16, 2016 TEMPERATURE (DEGREES F) MAX.....18 NORMAL.....39 MIN......1 NORMAL.....24 MEAN....10 NORMAL.....31 DEPARTURE FROM 30-YEAR NORMAL.......................-21 TOTAL DEPARTURE FOR THE MONTH.......................-34 [-2.3 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY..............55 DEPARTURE.........+21 TOTAL HEATING UNITS FOR THE MONTH.............532 DEPARTURE.........+33 TOTAL HEATING UNITS FOR THE SEASON...........1562 DEPARTURE........-199 TOTAL HEATING UNITS LAST SEASON TO DATE......1318 DIFFERENCE.......+244 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...................39 WNW AT 1:44 A.M. ASOS........................51 WNW AT 1:45 A.M. DAVIS.......................50 W AT 1:45 A.M. RMY N/A FASTEST MILE FOR YESTERDAY.....................36 W AT 1:54 A.M.* MAXIMUM 2-MINUTE ASOS AVERAGE..................33 WNW AT 1:49 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.................33 W AT 2:00 A.M. AVERAGE WIND SPEED AND DIRECTION.............14.4 W ASOS......................14.1 DAVIS.....................12.8 W [260 Deg.] *last of multiple occurances PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.14 DEPARTURE......-0.02 ASOS..............0.14 TOTAL PRECIPITATION FOR THE MONTH..........0.98 DEPARTURE......-1.64 ASOS..............1.07 TOTAL PRECIPITATION FOR THE YEAR..........37.95 DEPARTURE.....-13.20 ASOS.............38.50 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........1.7 DEPARTURE.......+1.2 TOTAL SNOWFALL FOR THE MONTH................3.4 DEPARTURE.......-2.4 TOTAL SNOWFALL FOR THE SEASON...............3.4 DEPARTURE.......-5.0 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 12/1 55/39/47/+10/0.20/0.0/385/69 36 W AERO 37 W RMY 36 12/2 48/34/41/+5/0.00/0.0/535/96 32 W AERO 32 W RMY N/A 13/3 44/31/38/+2/0.00/0.0/445/80 37 WNW AERO 39 WNW RMY 40 12/4 39/27/33/-2/0.00/0.0/355/64 25 NW AERO 25 NW RMY N/A 12/5 36/27/32/-3/0.13/0.4/000/00 26 W AERO 25 W RMY 29 12/6 42/30/36/+1/0.00/0.0/392/71 22 W AERO 21 W RMY N/A 12/7 39/34/37/+3/0.10/0.0/000/00 21 E AERO 21 E RMY N/A 12/8 40/29/35/+1/0.00/0.0/033/06 30 W AERO 31 W RMY 33 12/9 35/21/28/-6/0.00/0.0/549/100 35 W AERO 36 WNW RMY 34 12/10 27/17/22/-11/0.00/0.0/544/99 26 WNW AERO 27 WNW RMY 29 12/11 33/16/25/-8/0.06/0.4/411/75 17 SSW AERO 15 SW RMY N/A 12/12 41/27/34/+1/0.35/0.9/038/07 29 ESE AERO 29 SE RMY 30 12/13 41/30/36/+4/0.00/0.0/.../.. 25 WSW AERO 25 W RMY 27 12/14 40/26/33/+1/0.00/0.0/.../.. 30 WNW AERO 31 WNW RMY N/A 12/15 29/13/21/-11/T/T/.../.. 50 W AERO 62 W RMY 56 12/16 18/01/10/-21/0.00/0.0/.../.. 39 WNW AERO 51 WNW RMY N/A 12/17 Low temp since midnight is 18F; normal low is now 23F DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR DECEMBER 17 HIGH 63 IN 2000 LOW -10 IN 1942 PRECIP 3.03 INS. IN 1888 SNOWFALL 7.5 INS. IN 1988 PEAK GUST 78 MPH SSE IN 2000 RECORDS FOR DECEMBER 18 HIGH 59 IN 1928 LOW -11 IN 1919 PRECIP 1.44 INS. IN 1915 SNOWFALL 7.0 INS. IN 1904 PEAK GUST 76e W IN 1978 TODAY'S REPORT PREPARED BY: Cecilia Borries-Strigle