BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, DECEMBER 13, 2005 ALL TIMES ARE IN EASTERN STANDARD TIME Today's discussion.... A few hours of light snow flurries this morning left only a trace of snow. Arctic air arrived overnight and this morning's low temperature of 12 degrees was our coldest reading of the season to date. December continues to be a very cold month averaging 5.1 degrees below normal through the 12th. Precipitation for the month is about a half inch below normal through today while snowfall of 13 inches if far over the normal of 3.2 inches to date. Today's observations: 7 A.M. overcast with a break distant s-w-nw and very light snow flurry in progress, visibility 50 miles but 20 miles north thru east temp. 12; dewpoint 03; WIND WNW 17 gusting 25 MPH; windchill -5; six hourly min. temp. 12 deg; six hourly precip and snowfall: trace snow depth: 7 inches. BHO SA 1155 E18 OVC 50SW- 182/12/3/3015G22/007/ BINOVC/CLR SKY BND XTDNG ALG HRZN SSE-SW-NW SNSH/VSBY N 25 NE-SE 20 SBUKN PCPN VRY LGT WND 27V33/ WNDCHILL -5/ 8/5// 4/007 53026 MANUAL 6000/ 10020 20012 10 A.M. scattered clouds with 50 miles visibility and 15 miles northeast thru southeast in flurries and flurries ended past hour; temp. 14; dewpoint 04; wind WNW 16 MPH; 3-hourly precip. trace and 3-hourly snowfall is a trace... BHO SA 1455 34 SCT 50 208/14/4/3014/014/ SNSH NE-SE VSBY NE-SE 15 VSBY NW 60 SE30/ 8/500 51026 MANUAL 6000/ 1 P.M. clear with just a few clouds and visibility 60 miles but 70 miles to the northwest and 30 miles northeast thru southeast; temp. 19; dewpoint 04; wind WNW 12 MPH; six hourly max. temp. 19; min. temp. 12 deg. BHO SA 1755 CLR 60 218/19/4/3010/017/ SC/SCSL/FEW CU NE-SE AND FEW SC S-SW AND DSNT NNW-N VSBY NE-SE 30 NW 70/ 8/800 51010 10019 20012 WEATHER SUMMARY FOR MONDAY, DECEMBER 12: TEMPERATURE (DEGREES F) MAX.....38 NORMAL.....39 HAZEN....38.4 AT 1:54 P.M. MIN.....21 NORMAL.....25 HAZEN....20.9 AT 11:59 P.M. MEAN....30 NORMAL.....32 DEPARTURE FROM 30-YEAR NORMAL......- 2 TOTAL DEPARTURE FOR THE MONTH......-59 (-5.1 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..........35 DEPARTURE.....+2 TOTAL HEATING UNITS FOR THE MONTH.........431 DEPARTURE....+59 TOTAL HEATING UNITS FOR THE SEASON.......1496 DEPARTURE...-163 TOTAL HEATING UNITS LAST SEASON TO DATE..1659 DIFFERENCE...-36 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.........25 W AT 7:41 P.M. ** AEROVANE..........29 W AT 6:14 P.M. ASOS..............23 W AT 7:41 P.M. DAVIS.............26 W AT 6:14 P.M. FASTEST MILE FOR YESTERDAY...........18 WNW AT 6:17 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE........20 WNW AT 6:16 P.M. MAXIMUM 1-MINUTE DAVIS AVERAGE.......20 W AT 6:17 P.M. AVERAGE WIND SPEED AND DIRECTION...11.2 W ASOS............11.7 WSW [240 deg] DAVIS...........11.2 W [260 deg] ** last of several occurrences.... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....trace DEPARTURE....-0.14 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.47 DEPARTURE....-0.32 ASOS..............1.33 TOTAL PRECIPITATION FOR THE YEAR..........63.74 DEPARTURE...+15.44 ASOS.............62.48* *EXCLUDES 3.19 INCHES OF ERRONEOUS PRECIPITATION RECORDED FROM 1/23-1/28. SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........trace DEPARTURE....- 0.3 TOTAL SNOWFALL FOR THE MONTH...............13.1 DEPARTURE....+ 9.9 TOTAL SNOWFALL FOR THE SEASON..............15.2 DEPARTURE....+ 9.1 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2005......CALENDAR DAY DATA DATA REPORTED IN THE FOLLOWING ORDER: DATE MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available 12/1 43/35/39/+3/0/0/212/38 29 MPH N 12/2 41/31/36/0/0/0/217/39 46 MPH WSW Aero 51 MPH WSW 12/3 33/26/30/-5/0/0/534/96 46 MPH W Aero 50 MPH W 12/4 28/22/25/-10/0.24/2.2/000/00 22 MPH W 12/5 32/21/27/-8/0/0/.../.. 23 MPH WSW 12/6 33/23/28/-6/T/0.1/.../.. 31 MPH W Aero 36 MPH W 12/7 28/16/22/-12/T/T/479/87 44 MPH WNW Aero 50 MPH WNW 12/8 31/14/23/-10/0/0/.../.. 25 MPH NW 12/9 32/22/27/-6/1.23/10.8/000/00 53 MPH NW Aero 63 MPH NW TSTM/SLEET/GLAZE 12/10 34/21/28/-5/0/0/.../.. 30 MPH S 12/11 40/27/34/+2/0/0/493/90 27 MPH SSW 12/12 38/21/30/-2/0/0/241/44 25 MPH W 12/13 morning low temp. 12 deg; normal now 24 deg. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): A NEW DAILY EXTREME HAS BEEN SET FOR DECEMBER 2005 12/9 - A NEW MAXIMUM DAILY SNOWFALL OF 10.8 INCHES; the previous record was 6.0 inches in 2001 RECORDS FOR DECEMBER 13 HIGH 60 IN 1984 LOW 0 IN 1893 PRECIP 1.45 INS. IN 1983 SNOWFALL 9.0 INS. IN 1902 PEAK GUST 81e WNW IN 1976 RECORDS FOR DECEMBER 14 HIGH 62 IN 1901 LOW -6 IN 1893 PRECIP 1.94 INS. IN 2002 SNOWFALL 8.0 INS. IN 1907 PEAK GUST 78e ENE IN 1941 TODAY'S REPORT BY: Robert Skilling