BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, DECEMBER 26, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME CLOUDY AND WARMER TODAY WITH VERY LIGHT SNOW AND DRIZZLE OVERNIGHT... With an onshore northeast wind, periods of light precipitation since Friday evening amounted to 0.03 inch melted and a total of 0.2 inch new snow this morning. Temperatures just below freezing before midnight had risen to 34 deg F by 7 AM. As a result, no glazing was noted on the summit this morning. Light drizzle ended before 8 AM, but increasing winds from the ENE and low clouds have persisted all morning. With the temperature rising to the upper 30s for the first time since the 15th, the snow depth on the summit is shrinking quickly now from 9 inches a 7 AM to 7 inches at 1 PM. Friday was also the first day with above average mean temperature since the 15th. The monthly snowfall of 25.0 inches makes December so far the 14th snowiest December on record with five days remaining in the month. Today's observations: 7 A.M. Weather: Broken stratocumulus, overcast nimbostratus with light drizzle, few stratus fractus Temperature: 34F, Dew point: 34F, Wind: ENE at 13 kt Sea-level pressure: 30.46 inches Hg, rising Visibility: 8 miles, 12 miles NW, 10 miles N, 6 miles E-SSW 6-hour minimum temp: 32F 24-hour precipitation: 0.03 inch 24-hour snowfall: 0.2 inch Average snow depth: 9 inches BHO SA 1155 E20 BKN 30 OVC 8L- 314/34/34/0713/046/ FEW LWR STFRA VSBY NW 12 N 10 E-SSW 6 TOTAL NEW SNW PST 24 HRS 0.2 IN/ 8/52/ 4/009 55000 600// 70003/ 10034 20032 10 A.M. Weather: Broken and overcast stratocumulus, few lower stratocumulus Temperature: 36F, Dew point: 34F, Wind: ENE at 13 kt Sea-level pressure: 30.46 inches Hg, rising Visibility: 25 miles, 15 miles N-NE 3-hour precipitation: trace BHO SA 1455 E15 BKN 25 OVC 25 316/36/34/0713/046/ FEW LWR SC VSBY N-NE 15/ 8/5// 53002 6000/ 1 P.M. Weather: Broken and overcast stratocumulus Temperature: 37F, Dew point: 34F, Wind: ENE at 13G23 kt Sea-level pressure: 30.40 inches Hg, falling Visibility: 25 miles 6-hour maximum temp: 37F 6-hour precipitation: trace BHO SA 1755 E15 BKN 25 OVC 25 295/37/34/0713G23/040/ HAZY/ 8/5// 58021 6000/ 10037 20034 WEATHER SUMMARY FOR FRIDAY, DECEMBER 25, CHRISTMAS DAY TEMPERATURE (DEGREES F) MAX.....35 NORMAL.....36 MIN.....25 NORMAL.....21 MEAN....30 NORMAL.....29 DEPARTURE FROM 30-YEAR AVERAGE.............+1 TOTAL DEPARTURE FOR THE MONTH.............-44 [-2.0 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............35 DEPARTURE........-1 TOTAL HEATING UNITS FOR THE MONTH...........869 DEPARTURE.......+50 TOTAL HEATING UNITS FOR THE SEASON.........2029 DEPARTURE.......-79 TOTAL HEATING UNITS LAST SEASON TO DATE....2050 DIFFERENCE......-21 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............18 NNE AT 9:43 P.M. AEROVANE..............18 NNE AT 9:43 P.M. ASOS..................17 NE AT 9:43 P.M. DAVIS.................16 N AT 6:45 A.M. THE FASTEST MILE FOR YESTERDAY...........12 NNE AT 9:40 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............13 NE AT 9:44 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........13 N AT 6:57 A.M. AVERAGE WIND SPEED AND DIRECTION........9.1 NNE ASOS.................8.3 DAVIS................8.0 N [011 DEG] * last of several occurrences.... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.03 DEPARTURE....-0.12 ASOS..............0.01 TOTAL PRECIPITATION FOR THE MONTH..........5.02 DEPARTURE....+1.36 ASOS..............5.15 TOTAL PRECIPITATION FOR THE YEAR..........54.59 DEPARTURE....+4.27 ASOS.............55.91 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.2 DEPARTURE.....-0.2 TOTAL SNOWFALL FOR THE MONTH...............25.0 DEPARTURE....+16.7 TOTAL SNOWFALL FOR THE SEASON..............28.0 DEPARTURE....+16.8 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2009 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 when significant TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 12/1 41/28/35/-1/0/0/497/89 29 NW 12/2 51/33/42/+6/0.08/0/345/62 30 SSE 12/3 67/47/57/+22/1.01/0/428/77 69 SSE AERO 73 MPH SSE 12/4 52/40/46/+11/0/0/488/88 26 W 12/5 42/30/36/+1/0.79/4.7/000/00 36 N 12/6 33/25/29/-5/0.09/0.6/513/93 36 NW 12/7 36/25/31/-3/0/0/050/09 22 WSW 12/8 39/25/32/-3/0/0/512/93 27 WNW 12/9 45/29/37/+4/1.23/5.7/000/00 52 ENE AERO 46 MPH ENE 12/10 40/26/33/0/0/0/351/64 46 WSW AERO 39 MPH W 12/11 26/20/23/-9/0/0/395/72 46 WSW AERO 41 MPH WSW 12/12 30/18/24/-8/0/0/548/100 36 W AERO 33 MPH W 12/13 46/23/35/+3/0.74/0/274/50 35 SSE AERO 31 MPH SSE 12/14 41/33/37/+6/0/0/186/34 29 NW 12/15 46/34/40/+9/0/0/006/01 35 W AERO 32 MPH W 12/16 35/22/29/-2/T/T/459/84 43 W AERO 44 MPH W 12/17 22/7/15/-16/0/0/545/100 52 WNW AERO 52 MPH WNW 12/18 26/6/16/-14/0/0/540/99 37 W AERO 37 MPH W 12/19 30/14/22/-8/0.01/0.1/000/00 38 N 12/20 26/16/21/-9/1.04/13.7/000/00 42 NNW 12/21 30/15/23/-7/0/0/409/75 45 WNW AERO 45 MPH WNW 12/22 28/14/21/-8/0/0/.../.. 35 W 12/23 23/10/17/-12/0/0/.../.. 29 W 12/24 36/14/25/-4/0/0/.../.. 31 NW 12/25 35/25/30/+1/.../../.../.. 18 NNE 12/26 overnight low temperature 30 deg F, normal is 21 NEW DAILY RECORD FOR DECEMBER 2009 12/3 NEW RECORD HIGH MAXIMUM TEMPERATURE of 67F; surpasses previous record of 61F in 1932, 1950. 12/20 NEW RECORD DAILY SNOWFALL 13.7 INCHES; surpasses previous record of 8.3 inches in 1995 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR DECEMBER 26 HIGH 58 IN 1973,1982 LOW -12 IN 1980 PRECIP 3.64 INS. IN 1969 SNOWFALL 17.5 INS. IN 1909 PEAK GUST 84 MPH SSE IN 1957 RECORDS FOR DECEMBER 27 HIGH 57 IN 1895,1949 LOW -4 IN 1903 PRECIP 2.43 INS. IN 1969 SNOWFALL 11.2 INS. IN 1947 PEAK GUST 53e W IN 1957,1978; WNW 1976 TODAY'S REPORT PREPARED BY: Mike Iacono