BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY WEDNESDAY, DECEMBER 20, 2017 ALL TIMES ARE IN EASTERN STANDARD TIME STRONG WEST WIND LEAVES CLOSE TO SEASONABLE TEMPERATURES... Today winds from the west were strong frequently gusting over 29 kts (33 MPH). So far today we have had a peak gust of 36 kts (41 MPH). Yesterday temperatures were well above seasonable with a max of 49F, this is 11 degrees above the daily normal of 38F. Since midnight the low is 36F which is 14 degrees above the normal daily minimum of 22F. Today temperatures returned to more seasonable conditions with a high maximum of 41F by 1:00 PM, which is 3 degrees above the normal of 38F. Overnight a rain shower left a trace of precip. on top of Great Blue Hill. Humidity dropped throughout the day from 54 to 32%. This made for excellent visibility at 80 miles during the 10:00 AM and 1:00 PM observations. Today's Observations: 7 A.M. Weather: Broken altocumulus, few cumulus distant along horizon ENE-E Temperature: 37F; Dew Point: 22F; Wind: W at 11 kts Sea-level pressure: 29.72 ins. Hg, rising, then more quickly Visibility: 60 miles 6-hr Max temp: 42F 6-hr Min temp: 36F 24-hr precip: Trace 24-hr snowfall: 0.0 ins. Snow cover: 0 ins. BHO SA 1155 E70 BKN 60 066/37/22/2711/972/ FEW CU DSNT ALG HRZN ENE-E/ 8/130 53021 10042 20036 10 A.M. Weather: Broken cumulus Temperature: 38F; Dew Point: 18F; Wind: W at 25G32 kts, Peak Wind: 32 kts W at 9:54 A.M. Sea-level pressure: 29.77 ins. Hg, falling, then more slowly Visibility: 80 miles 3-hr precip: 0.00 ins. 3-hr snowfall: 0.0 ins. BHO SA 1455 E60 BKN 80 082/38/18/2725G32/977/ PK WND 2732/54/ 8/030 53016 1 P.M. Weather: Scattered cumulus, scattered cirrostratus Temperature: 41F; Dew Point: 14F; Wind: W at 13G28 kts, Peak Wind: 28 kts W at 12:47 P.M. Sea-level pressure: 29.74 ins. Hg, falling, steadily Visibility: 80 miles 6-hr Max temp: 41F 6-hr Min temp: 37F 6-hr precip: 0.00 ins. 6-hr snowfall: 0.0 ins. Snow cover: 0 ins. BHO SA 1755 60 SCT 250 SCT 80 076/41/14/2813G28/975/ PK WND 2728/47/ 8/105 58006 10041 20037 SUMMARY FOR TUESDAY, DECEMBER 19, 2017 TEMPERATURE (DEGREES F) MAX.....49 NORMAL.....38 MIN.....34 NORMAL.....23 MEAN....42 NORMAL.....30 DEPARTURE FROM 30-YEAR NORMAL..........................+12 TOTAL DEPARTURE FOR THE MONTH...........................-6 [-0.5 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY.............23 DEPARTURE.........-12 TOTAL HEATING UNITS FOR THE MONTH............608 DEPARTURE..........+5 TOTAL HEATING UNITS FOR THE SEASON..........1577 DEPARTURE........-287 TOTAL HEATING UNITS LAST SEASON TO DATE.....1663 DIFFERENCE........-86 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...................36 WNW AT 10:59 P.M. AERO........................35 SW AT 8:39 P.M. ASOS........................36 SW AT 8:10 P.M. DAVIS.......................37 SW AT 8:09 P.M. RMY 38 FASTEST MILE FOR YESTERDAY.....................25 WNW AT 11:00 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE..................25 W AT 11:01 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.................25 WNW AT 11:01 P.M. AVERAGE WIND SPEED AND DIRECTION.............14.6 SW ASOS......................14.1 DAVIS.....................14.0 WSW [248 DEG.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE......-0.15 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.54 DEPARTURE......-1.54 ASOS..............1.63 TOTAL PRECIPITATION FOR THE YEAR..........51.38 DEPARTURE......-0.23 ASOS...............N/A ** ** ASOS annual total not available due to erroneous readings SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.......-0.5 TOTAL SNOWFALL FOR THE MONTH................5.7 DEPARTURE.......-1.5 TOTAL SNOWFALL FOR THE SEASON...............5.7 DEPARTURE.......-4.1 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 50/35/43/+6/0.04/262/47 28 NW AERO 29 NW RMY 30 12/02 42/29/36/0/0.00/033/06 20 NNW AERO 18 NNW RMY N/A 12/03 42/32/37/+1/0.00/172/31 14 N AERO 10 N RMY N/A 12/04 43/32/38/+3/0.00/522/94 16 E AERO 14 E RMY N/A 12/05 58/34/46/+11/0.18/000/00 62 S AERO 66 S RMY 65 12/06 56/32/44/+9/0.54/160/29 52 S AERO 55 S RMY N/A 12/07 44/30/37/+3/0.00/540/98 25 WSW AERO 24 WSW RMY 25 12/08 38/28/33/-1/0.00/116/21 21 W AERO 18 W RMY 20 12/09 34/28/31/-3./..../000/00 23 NNW AERO 23 NNW RMY 23 12/10 35/27/31/-2/..../384/70 30 W AERO 30 W RMY 27 12/11 38/29/34/+1/0.00/301/55 23 W AERO 21 W RMY 22 12/12 43/31/37/+4/0.06/000/00 35 W AERO 31 W RMY N/A 12/13 31/18/25/-7/0.00/312/57 44 W AERO 44 W RMY 44 12/14 27/14/21/-11/T/.../.. 35 WSW AERO 33 W RMY 34 12/15 24/12/18/-14/T/.../.. 25 W AERO 23 W RMY N/A 12/16 32/17/25/-6/0.00/.../.. 33 W AERO 35 W RMY 36 12/17 27/14/21/-10/0.00/.../.. 21 NW AERO 21 NW RMY 20 12/18 35/20/28/-3/T/.../.. 20 SSE AERO 16 SSE RMY 20 12/19 49/34/42/+12/..../.../.. 36 WNW AERO 35 SW RMY 38 12/20 Low temp since midnight is 36F; normal low is now 22F DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR DECEMBER 20 HIGH 61 IN 1957 LOW -16 IN 1942 PRECIP 1.69 INS. IN 1936 SNOWFALL 13.7 INS. IN 2009 PEAK GUST 75 MPH S IN 2002 RECORDS FOR DECEMBER 21 HIGH 60 IN 1957 LOW -10 IN 1942 PRECIP 2.01 INS. IN 1946 SNOWFALL 11.4 INS. IN 1954 PEAK GUST 77 MPH SSE IN 1957 TODAY'S REPORT PREPARED BY: Kaitlin Geagan<