BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, DECEMBER 25, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Today's observations: 7 A.M. Weather: Clear with a few stratocumulus and cirrus Temperature: 26F, Dew point: 24F, Wind: N at 12 kt Sea-level pressure: 30.45 inches Hg, rising Visibility: 25 miles 6-hour minimum temp: 25F Average snow depth: 9 inches BHO SA 1155 CLR 25 313/26/24/3512/045/ SC OFFSHR E-SE FEW THN CI S-SW/ 8/401 53007 4/009 10029 20025 10 A.M. Weather: Scattered stratocumulus, thin broken cirrus Temperature: 33F, Dew point: 28F, Wind: NNE at 11 kt Sea-level pressure: 30.47 inches Hg, rising Visibility: 25 miles BHO SA 1455 20 SCT 200 –BKN 25 318/33/28/0211/047/ K LYR ALGN HRZN SW-N/ 8/401 51005 WEATHER SUMMARY FOR THURSDAY, DECEMBER 24 TEMPERATURE (DEGREES F) MAX.....36 NORMAL.....36 MIN.....14 NORMAL.....21 MEAN....25 NORMAL.....29 DEPARTURE FROM 30-YEAR AVERAGE.............-4 TOTAL DEPARTURE FOR THE MONTH.............-45 [-2.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............40 DEPARTURE........+4 TOTAL HEATING UNITS FOR THE MONTH...........834 DEPARTURE.......+51 TOTAL HEATING UNITS FOR THE SEASON.........1994 DEPARTURE.......-78 TOTAL HEATING UNITS LAST SEASON TO DATE....2025 DIFFERENCE......-31 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............31 NW AT 6:05 A.M. AEROVANE..............32 NW AT 6:07 A.M. ASOS..................30 NNW AT 6:05 A.M. DAVIS.................32 WNW AT 6:07 A.M. THE FASTEST MILE FOR YESTERDAY...........23 NW AT 6:09 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE............21 NNW AT 6:11 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........23 WNW AT 6:11 A.M. AVERAGE WIND SPEED AND DIRECTION...... 10.6 NW ASOS................10.7 DAVIS...............11.2 NW [308 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..........4.99 DEPARTURE....+1.48 ASOS..............5.14 TOTAL PRECIPITATION FOR THE YEAR..........54.56 DEPARTURE....+4.39 ASOS.............55.90 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.....-0.4 TOTAL SNOWFALL FOR THE MONTH...............24.8 DEPARTURE....+16.9 TOTAL SNOWFALL FOR THE SEASON..............27.8 DEPARTURE....+17.0 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 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 25 HIGH 62 IN 1889 LOW -11 IN 1980 PRECIP 1.37 INS. IN 2002 SNOWFALL 8.5 INS. IN 2002 PEAK GUST 80 MPH NW IN 1971 TODAY'S REPORT PREPARED BY: Andrew Hoell