BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, DECEMBER 31, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Snow began just after 11:00 A.M. and accumulated 1.0 inch as of 1:00 P.M. An additional 0.7 inch of snow fell between 1:00 and 2:00 P.M. Best wishes for a happy and healthy new year from the Blue Hill Observatory staff. Today's observations: 7 A.M. Weather: Overcast stratocumulus, break in overcast distant NE to E, thin spots in overcast overhead, higher altocumulus clouds visible Temperature: 25F, Dew point: 14F, Wind: SE at 12 kts Sea-level pressure: 30.29 inches Hg, rising Visibility: 30 miles, light haze 6-hour minimum temp: 22F 24-hour precipitation: 0.00 inch Average snow depth: None BHO SA 1155 E25 BKN 80 OVC 30 258/25/14/1412/029/ BINOVC DSNT NE-E THN SPTS IOVC OVHD HIER AC CLDS VSBL LGT HZ/ 8/57/ 53004 10025 20022 10 A.M. Weather: Overcast altostratus Temperature: 28F, Dew point: 20F, Wind: SE at 9 kts Sea-level pressure: 30.24 inches Hg, falling Visibility: 25 miles, thin fog, visibility higher NW to NE BHO SA 1455 E70 OVC 25 239/28/20/1409/024/ THN FG VSBY HIER NW-NE/ 8/07/ 55019 1 P.M. Weather: Overcast stratus, moderate snow Temperature: 27F, Dew point: 27F, Wind: SW at 3 kts Sea-level pressure: 30.18 inches Hg, falling Visibility: 1/8 mile, snow, fog 6-hour maximum temp: 29F 3-hour precipitation: 0.08 inch 3-hour snowfall: 1.0 inch BHO SA 1755 E5 OVC 1/8SF 219/27/27/2203/018/ THN FG TOTAL NEW SNW PST 3 HRS 1.0 IN/ 8/7// 58020 MANUAL 6008/ ASOS 60006 10029 20025 WEATHER SUMMARY FOR WEDNESDAY, DECEMBER 30 TEMPERATURE (DEGREES F) MAX.....26 NORMAL.....35 MIN......7 NORMAL.....20 MEAN....17 NORMAL.....28 DEPARTURE FROM 30-YEAR AVERAGE............-11 TOTAL DEPARTURE FOR THE MONTH.............-35 [-1.4 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............48 DEPARTURE.......+11 TOTAL HEATING UNITS FOR THE MONTH..........1045 DEPARTURE.......+42 TOTAL HEATING UNITS FOR THE SEASON.........2205 DEPARTURE.......-87 TOTAL HEATING UNITS LAST SEASON TO DATE....2190 DIFFERENCE......+15 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............36 W AT 3:45 A.M. AEROVANE..............35 W AT 3:45 A.M. ASOS..................33 NW AT 10:45 A.M. DAVIS.................35 W AT 3:45 A.M. THE FASTEST MILE FOR YESTERDAY...........26 W AT 10:46 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............24 NW AT 10:44 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........26 W AT 10:44 A.M. AVERAGE WIND SPEED AND DIRECTION.......14.3 W ASOS................13.9 DAVIS...............13.6 W [272 DEG] * 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..........5.55 DEPARTURE....+1.14 ASOS..............5.74 TOTAL PRECIPITATION FOR THE YEAR..........55.12 DEPARTURE....+4.05 ASOS.............56.50 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.....-0.4 TOTAL SNOWFALL FOR THE MONTH...............25.1 DEPARTURE....+14.8 TOTAL SNOWFALL FOR THE SEASON..............28.1 DEPARTURE....+14.9 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/-8/0/0/528/97 35 W 12/23 23/10/17/-12/0/0/441/81 29 W 12/24 36/14/25/-4/0/0/055/10 31 NW 12/25 35/25/30/+1/0.02/0.1/185/34 18 NNE 12/26 42/30/36/+8/0.01/0.1/000/00 38 E 12/27 52/35/44/+16/0.45/0/033/06 50 ESE AERO 51 MPH SE 12/28 41/27/34/+6/0.08/0.1/.../.. 40 W AERO 42 MPH W 12/29 27/8/18/-10/0/0/.../.. 58 W AERO 58 MPH W 12/30 26/7/17/-11/0/0/.../.. 33 W 12/31 our morning low temp: 22F; the normal low is now 20F 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 31 HIGH 62 IN 1965 LOW -12 IN 1917 PRECIP 0.96 INS. IN 1906 SNOWFALL 7.5 INS. IN 2008 PEAK GUST 78 MPH NW IN 1990 RECORDS FOR JANUARY 1 HIGH 58F IN 1966 LOW -6F IN 1918 PRECIP 1.45 INS. IN 1982 SNOWFALL 7.2 INS. IN 1938 PEAK GUST 90e MPH S IN 1945 TODAY'S REPORT PREPARED BY: Stephanie Radner