BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, DECEMBER 10, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME YESTERDAY'S WINTRY MESS ENDED AS LIGHT DRIZZLE INTO THE EVENING; LIGHT SNOW BEGAN AT 8 A.M. TODAY WITH 0.8 INCH THROUGH 1 P.M. Yesterday's wintry precipitation transitioned to light drizzle during the afternoon before ending late in the evening. The storm total snowfall/sleet was 0.6 inch, with total liquid precipitation of 0.35 inch. The temperature has remained in the lower 30s so far today. Snow began falling at 7:59 A.M. and continued for another hour before coming down hard enough to begin accumulating. Snowfall through 1 P.M. has reached 0.8 inch, with snow continuing to fall after 1 P.M. The liquid to snow ratio so far has been 1:13. As snow continues to fall, this will likely be our first 1 inch or greater snowfall so far this season. Plenty of cold air looks poised to invade the area behind the storm system that is currently bringing the light snow. Today's Observations: 7 A.M. Weather: Broken altocumulus (3 levels), broken cirrus, higher altocumulus and cirrus layers visible distant ESE-SSW, thin fog all quadrants, frost most surfaces, total new snow past 24 hours 0.2 inch (ice pellets) Temperature: 32F; Dew Point: 31F; Wind: SW at 5 kts. Sea-level pressure: 29.92 ins. Hg, rising then falling Visibility: 50 miles, thin fog all quadrants 24-hr. snowfall: 0.2 inch 24-hr. precip: 0.28 inch 6-hr. min temp: 31F BHO SA 1155 E100 BKN 120 BKN 140 BKN 250 BKN 50 132/32/31/2305/992/ HIER AC AND CI VSBL DSNT ESE-SSW THN FG ALQDS FROST MST SFCS TOTAL NEW SNW PST 24 HRS 0.2 IN/ 8/071 50005 ASOS 70029 MANUAL 70028 10033 20031 10 A.M. Weather: Light snow and fog, broken stratocumulus, overcast nimbostratus, light snow continued, total new snow past 3 hours 0.1 inch Temperature: 31F; Dew Point: 31F; Wind: SW at 5 kts, Wind: Direction gradually backing over the past hour (counterclockwise) Sea-level pressure: 29.93 ins. Hg, rising then falling Visibility: 3/4 mile, variable 1/2 to 1 mile, light snow and fog 3-hr. snowfall: 0.1 inch 3-hr. precip: 0.01 inch BHO SA 1455 E4 BKN 25 OVC 3/4VS-F 137/31/31/2305/993/ VSBY 1/2V1 WND GRDLY BACKING PST HR S- CTD TOTAL NEW SNW PST 3 HRS 0.1 IN/ 8/72/ 50005 MANUAL 60001 ASOS 60001 1 P.M. Weather: Light snow and fog, broken stratocumulus (2 levels), overcast nimbostratus, light snow continued mostly very light, total new snow past 6 hours 0.8 inch Temperature: 30F; Dew Point: 30F; Wind: SW at 5 kts. Sea-level pressure: 29.82 ins. Hg, falling then falling more slowly Visibility: 3 miles, light snow and fog 6-hr. snowfall 0.8 inch 6-hr. precip: 0.06 inch 6-hr. max temp: 32F 6-hr. min temp: 30F BHO SA 1755 E5 BKN 40 BKN 60 OVC 3S-F 097/30/30/2205/982/ S- CTD MSTLY VRY LGT TOTAL NEW SNW PST 6 HRS 0.8 IN/ 8/82/ 56040 ASOS 60006 MANUAL 60006 10032 20030 WEATHER SUMMARY FOR MONDAY, DECEMBER 9, 2013 TEMPERATURE (DEGREES F) MAX.....41 NORMAL.....41 MIN.....25 NORMAL.....26 MEAN....33 NORMAL.....34 DEPARTURE FROM 30-YEAR NORMAL......................-1 TOTAL DEPARTURE FOR THE MONTH.....................+15 [+1.5 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY..............32 DEPARTURE.........+1 TOTAL HEATING UNITS FOR THE MONTH.............254 DEPARTURE........-15 TOTAL HEATING UNITS FOR THE SEASON...........1478 DEPARTURE........-53 TOTAL HEATING UNITS LAST SEASON TO DATE......1368 DIFFERENCE......+110 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..................28 E AT 8:08 A.M. AERO.......................28 E AT 8:24 A.M. * ASOS.......................27 E AT 8:25 A.M. DAVIS......................25 E AT 8:24 A.M. RMY 24 FASTEST MILE FOR YESTERDAY....................22 E AT 8:24 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE.................21 E AT 8:25 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE................19 WSW AT 9:07 P.M. AVERAGE WIND SPEED AND DIRECTION............10.5 E ASOS.....................10.8 DAVIS.....................9.2 ENE [071 degrees] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.28 DEPARTURE.............+0.12 ASOS..............0.29 TOTAL PRECIPITATION FOR THE MONTH..........1.15 DEPARTURE.............-0.33 ASOS..............1.12 TOTAL PRECIPITATION FOR THE YEAR..........47.75 DEPARTURE..............-2.26 ASOS..............N/A** ** ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M.......0.2 DEPARTURE.............-0.2 TOTAL SNOWFALL FOR THE MONTH.............0.6 DEPARTURE.............-2.2 TOTAL SNOWFALL FOR THE SEASON............0.8 DEPARTURE.............-4.6 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2013 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust RMY: RMY = R.M. Young wind gust recording system added 8/9/2011 TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 12/1 45/30/38/+1/0.28/T/000/00 22 SSE AERO 23 MPH SSE RMY 23 12/2 38/34/36/0/T/0.0/000/00 15 NW AERO 15 MPH NW RMY 16 12/3 45/32/39/+3/0.00/0.0/.../.. 18 NNW AERO 18 MPH NNW RMY 20 12/4 43/29/36/+1/0.00/0.0/.../.. 21 WNW AERO 21 MPH WNW RMY 21 12/5 53/38/46/+11/0.02/0.0/000/00 36 S AERO 40 MPH S RMY 39 12/6 55/33/44/+9/0.38/T/000/00 25 SSW AERO 28 MPH SSW RMY N/A 12/7 40/26/33/-1/0.12/T/.../.. 23 NW AERO 25 MPH NW RMY N/A 12/8 30/22/26/-8/T/T/.../.. 25 NW AERO 27 MPH NW RMY N/A 12/9 41/25/33/-1/0.35/0.6/000/00 28 E AERO 28 MPH E RMY 24 12/10 morning low temp: 31F; the normal low is now 26F DAILY RECORDS FOR DECEMBER 2013 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR DECEMBER 10 HIGH 62 IN 1946 LOW -6 IN 1902 PRECIP 1.67 INS. IN 1907 SNOWFALL 6.0 INS. IN 1905 PEAK GUST 66e SW IN 1940 RECORDS FOR DECEMBER 11 HIGH 63 IN 1911 LOW -1 IN 1988 PRECIP 2.36 INS. IN 1992 SNOWFALL 6.0 INS. IN 1894 PEAK GUST 78 S IN 1969 TODAY'S REPORT PREPARED BY: Sean Fankhauser