BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, DECEMBER 20, 2014 ALL TIMES ARE IN EASTERN STANDARD TIME PARTIAL SUNSHINE THIS MORNING FADES AS LOW CLOUDS MOVE IN FROM THE OCEAN BY MID-DAY...LIGHT SNOW FALLING ALONG SHORELINE TO THE EAST AT LATE MORNING REACHES SUMMIT JUST AFTER 1 PM EST... The low temperature this morning of 24F was the coldest reading since 16F on December 8th. The temperature has struggled to climb today, and it has reached only the low 30s by early afternoon. There was partial sunshine for a few hours this morning with a deck of stratocumulus along the shoreline to the east. This moved inland during the morning and overspread the area by late morning. A few light snow showers and flurries were occurring along the coastline with the visibility dropping to about 2 miles in light snow at Plymouth at mid-day. Snow showers were observed just to the east of the hill at 1 PM EST moving west-southwest, and light snow began on the summit at 1:07 PM EST. This continued intermittently for the rest of that hour, then the visibility improved and the snow ended by 2 PM EST. Each of the local ponds, Houghton's and Ponkapoag, have about 2/10 ice cover today. For a time before the snow began, the visibility increased to 75 miles to the WNW, and using binoculars the snow cover on the summit of Grand Monadock, 67 miles to the NW, could be seen. Today's Observations: 7 A.M. Weather: Scattered stratocumulus (2 layers), few cumulus fractus ENE-SW, hazy Temperature: 24F; Dew Point: 20F; Wind: N at 9 kts Sea-level pressure: 30.25 ins. Hg, rising then more rapidly Visibility: 30 miles, hazy 6-hr max temp: 25F 6-hr min temp: 24F 24-hr precip: 0.00 ins. 24-hr snowfall: 0.00 ins. BHO SA 1155 20 SCT 30 SCT 30 245/24/20/3509/025/ FEW CUFRA ENE-SW HAZY/ 8/570 53021 10025 20024 10 A.M. Weather: Scattered stratocumulus, scattered altocumulus, few cumulus fractus vicinity of station, hazy Temperature: 31F; Dew Point: 22F; Wind: N at 10 kts Sea-level pressure: 30.29 ins. Hg, rising then more slowly Visibility: 45 miles, visibility SW-NW 55, NE-SE 35, hazy BHO SA 1455 20 SCT 70 SCT 45 259/31/22/3610/029/ FEW CUFRA VCNTY STN VSBY SW-NW 55 NE-SE 35 HAZY/ 8/570 51014 1 P.M. Weather: Broken stratocumulus, overcast stratocumulus, higher clouds visible distant W-N, snow shower E moving WSW Temperature: 31F; Dew Point: 26F; Wind: N at 6 kts, Wind: Light Sea-level pressure: 30.27 ins. Hg, falling Visibility: 50 miles, visibility W-WNW 75, ENE-E 6, decreasing E 6-hr max temp: 31F 6-hr min temp: 24F 6-hr precip: 0.00 ins. BHO SA 1755 E15 BKN 25 OVC 50 250/31/26/3606/027/ HIR CLDS VSBL DSNT W-N VSBY W-WNW 75 ENE-E 6 VSBY DCRNG E SW E MVNG WSW WND LGT/ 8/5// 56009 10031 20024 SUMMARY FOR FRIDAY, DECEMBER 19, 2014 TEMPERATURE (DEGREES F) MAX.....34 NORMAL.....38 MIN.....25 NORMAL.....23 MEAN....30 NORMAL.....30 DEPARTURE FROM 30-YEAR NORMAL..........................0 TOTAL DEPARTURE FOR THE MONTH........................+39 [+1.9 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY..............35 DEPARTURE............0 TOTAL HEATING UNITS FOR THE MONTH.............562 DEPARTURE..........-41 TOTAL HEATING UNITS FOR THE SEASON...........1721 DEPARTURE.........-143 TOTAL HEATING UNITS LAST SEASON TO DATE......1897 DIFFERENCE........-176 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..................26 NW AT 9:22 A.M. ASOS.......................29 NW AT 9:22 A.M. DAVIS......................27 WNW AT 9:22 A.M. RMY 29 FASTEST MILE FOR YESTERDAY....................21 NW AT 9:21 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE.................20 NW AT 9:23 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE................18 NW AT 9:22 A.M. AVERAGE WIND SPEED AND DIRECTION............11.3 NW ASOS.....................10.8 DAVIS.....................9.0 NW [309 degrees] * Last of several occurrences... 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..........5.85 DEPARTURE.....+2.77 ASOS..............6.01 TOTAL PRECIPITATION FOR THE YEAR..........53.61 DEPARTURE.....+2.00 ASOS.............54.20 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE......-0.5 TOTAL SNOWFALL FOR THE MONTH................0.6 DEPARTURE......-6.6 TOTAL SNOWFALL FOR THE SEASON...............9.3 DEPARTURE......-0.5 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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 12/1 63/37/50/+13/0.01/0.0/391/70 28 WNW RMY 31 12/2 37/30/34/-2/0.10/T/000/00 26 E RMY 29 12/3 49/34/42/+6/0.31/0.0/000/00 40 W RMY 43 12/4 41/27/34/-1/0.00/0.0/505/91 29 WNW RMY N/A 12/5 42/23/33/-2/0.12/0.0/382/69 21 E RMY 22 12/6 43/36/40/+5/0.99/0.0/000/00 25 NNW RMY N/A 12/7 36/18/27/-7/0.15/0.0/193/35 31 N RMY 34 12/8 25/16/21/-13/0.01/0.1/000/00 24 N RMY N/A 12/9 48/25/37/+3/3.23/0.0/000/00 48 ENE RMY 52 12/10 47/35/41/+8/0.43/0.0/000/00 35 NNE RMY 37 12/11 35/29/32/-1/0.05/0.5/000/00 27 SW RMY 27 12/12 36/26/31/-2/0.00/0.0/230/42 23 WNW RMY 25 12/13 40/27/34/+2/0.00/0.0/191/35 28 NW RMY 28 12/14 43/28/36/+4/0.00/0.0/377/69 20 NW RMY 20 12/15 41/28/35/+3/0.00/0.0/536/98 17 NW RMY 17 12/16 42/33/38/+7/T/T/011/02 17 E RMY N/A 12/17 45/37/41/+10/0.43/0.0/000/00 27 W RMY N/A 12/18 41/32/37/+6/0.02/T/213/39 35 WNW RMY 38 12/19 34/25/30/0/0.00/0.0/000/00 26 NW RMY 29 12/20 morning low temp: 24F since midnight; normal low is now 22F DAILY RECORDS FOR DECEMBER 2014: -DAILY PRECIPITATION RECORD FOR DECEMBER 9 2014 Old record of 1.51 inches set in 1952, replaced with new record of 3.23 inches. 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: Mike Iacono