BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY WEDNESDAY, DECEMBER 26, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME MILD TEMPERATURES OVER THE CHRISTMAS HOLIDAYS NEGATIVE TEMPERATURE DEPARTURE LESS THAN 4 DEGREES PRECIPITATION FOR THE MONTH WELL OVER 5 INCHES Temperatures have averaged 12 degrees milder than average over the 3-day period, December 23-25, including +6 degrees on Christmas Day. The monthly negative temperature departure is now down to less than 4 degrees below normal after being more than six degrees on the cold side earlier in the month. Our snow cover is at an average of about 2 inches on the summit with lots of bare ground. However, in the wooded areas on the north side of the summit and on the north side of the hill snow depths are still in the order of 4 to 6 inhces. Total snowfall for the month stands at 28.2 inches, and the precipitation total is 5.34 or well past the December normal of 4.56 inches. Today's observations: 7 A.M. Weather: Thin overcast cirrus clouds Temperature: 27F, Dew point: 23F, Wind: WSW at 9 kts Sea-level pressure: 30.26 inches Hg, rising Visibility: 20 miles, thin fog below inversion 6-hour min temp: 26F Snow on ground: 2 inches (patchy snow cover) (4 to 6 inches in woods north side of hill) BHO SA 1155 250 SCT 300 -OVC 20 247/27/23/2509/026/ LWR DENS CI E-SW BINOVC DSNT NW-NE THN FG BLO INVSN HVY FROST/ 8/002 4/002 51004 10029 20026 10 A.M. Weather: High thin overcast cirrus and cirrostratus clouds Temperature: 31F, Dew point: 24F, Wind: W at 5 kts Sea-level pressure: 30.27 inches Hg, rising Visibility: 15 miles, thin smoke layer NW-E, hazy Visibility: higher W-N and 45 above inversion WNW BHO SA 1455 250 SCT 300 -OVC 15 252/31/24/2805/027/ LWR DENS CI SE-W BINOVC DSNT WNW-NE HALO/PARAHELION THN K LYR NW-E HAZY VSBY HIER W-N AND WNW 45 ABV INVSN WNW/ 8/007 53005 1 P.M. Weather: High thin overcast cirrus and cirrostratus clouds, patches of dense cirrus Temperature: 36F, Dew point: 25F, Wind: N at 3 kts Wind: light Sea-level pressure: 30.19 inches Hg, falling Visibility: 20 miles, thin smoke layer NW-E, hazy Visibility: 15 miles NE-SE 6-hourly max. temp. 36F BHO SA 1755 220 SCT 250 -OVC 20 223/36/25/3603/019/ FEW AC SE-SW PTCHS DENS CI ALQDS BINOVC DSNT NW-N THN K LYR NW-E VSBY NE-SE 15 HAZY ALQDS WND LGT/ 8/042 56029 10036 20027 WEATHER SUMMARY FOR TUESDAY, DECEMBER 25, CHRISTMAS DAY TEMPERATURE (DEGREES F) MAX.....40 NORMAL.....36 MIN.....29 NORMAL.....21 MEAN....35 NORMAL.....29 DEPARTURE FROM 30-YEAR NORMAL.......... +6 TOTAL DEPARTURE FOR THE MONTH..........-84 [-3.6 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............30 DEPARTURE.......-6 TOTAL HEATING UNITS FOR THE MONTH...........909 DEPARTURE......+90 TOTAL HEATING UNITS FOR THE SEASON.........1989 DEPARTURE.....-119 TOTAL HEATING UNITS LAST SEASON TO DATE....1678 DIFFERENCE....+311 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............32 WSW AT 12:02 P.M. AEROVANE.............32 WSW AT 12:13 P.M. ASOS.................N/A * DAVIS................33 WSW AT 12:13 P.M. FASTEST MILE FOR YESTERDAY............. 25 W AT 12:06 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........N/A * MAXIMUM 2-MINUTE DAVIS AVERAGE..........26 W AT 11:31 A.M. AVERAGE WIND SPEED AND DIRECTION......13.3 W ASOS...............N/A * DAVIS..............13.9 WSW [250 deg] * ASOS WIND SYSTEM MALFUNCTIONED ON DEC 19. 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..........5.34 DEPARTURE....+1.68 ASOS..............5.42 TOTAL PRECIPITATION FOR THE YEAR..........44.18 DEPARTURE....-6.14 ASOS.............43.64 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.....-0.4 TOTAL SNOWFALL FOR THE MONTH...............28.2 DEPARTURE....+19.9 TOTAL SNOWFALL FOR THE SEASON..............29.0 DEPARTURE....+17.8 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2007...CALENDAR DAY DATA DATA REPORTED: 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 33/15/24/-12/0/0/493/88 54 WNW Aero 57 MPH WNW 12/2 24/15/20/-16/0.03/0.3/000/00 28 WNW 12/3 38/23/31/-4/0.62/1.7/000/00 47 W 12/4 27/17/22/-13/T/T/111/20 48 W 12/5 29/17/23/-12/T/T/244/44 23 WNW 12/6 28/15/22/-12/0/0/554/100 31 WNW 12/7 34/21/28/-6/0.07/0.7/000/00 24 SSW 12/8 41/25/33/0/0/0/452/82 32 W 12/9 33/25/29/-4/0.08/T/000/00 16 NW 12/10 30/26/28/-5/0.10/0/000/00 18 N 12/11 36/22/29/-3/0.09/0/258/47 25 S 12/12 44/22/36/+4/T/0/88/16 39 W 12/13 29/20/25/-7/1.08/9.2/000/00 24 ENE 12/14 37/20/29/-2/0.02/0.2/038/07 28 WSW 12/15 28/15/22/-9/0/0/.../.. 31 WNW 12/16 43/23/33/+2/1.62/8.5/000/00 54 NE 12/17 32/15/24/-7/0/0/.../.. 62 W Aero 65 MPH W 12/18 31/10/21/-9/0/0/.../.. 20 W 12/19 38/24/31/+1/0.04/0/.../.. 19 E 12/20 33/26/30/0/0.90/7.4/000/00 24 NNW 12/21 28/22/25/-5/0.03/0.2/000/00 25 N 12/22 32/26/29/0/0/0/../../.../.. 21 ESE 12/23 54/33/44/+15/0.64/0/000/00 65 SE Aero 70 MPH SE 12/24 53/32/43/+14/0.01/0/.../.. 50 S Aero 51 MPH S 12/25 40/29/35/+6/0/0/.../.. 32 WSW 12/26 morning low temp: 26F; our normal low is now 21F NEW DAILY RECORDS FOR DECEMBER 2007: Dec 13: Record daily snowfall of 9.2 inches surpasses previous record of 9.0 inches in 1902. Dec.16: Record daily snowfall of 8.5 inches surpasses previous record of 7.0 inches in 1896. 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 INCHES IN 1969 SNOWFALL 17.5 INCHES 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: Robert Skilling