BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, DECEMBER 17, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME STRONGEST WINDS FROM THE WEST OVER 60 MPH EARLY TODAY OCCURRED IN THE WAKE OF THE INTENSE LOW PRESSURE SYSTEM OR NOR-EASTER WHICH BROUGHT 8.5 INCHES OF SNOW AND 1.62 INCHES OF PRECIPITATION INCLUDING SNOW, ICE PELLETS, AND RAIN (BRIEF FREEZING RAIN); LATE AFTERNOON TEMP. HIT 43 DEGREES AT 5:54 P.M. WIND SHIFTED NORTH-NORTHEAST TO WEST BAROMETER DROPS TO NEAR 28.9 INCHES EARLY EVENING Very strong and gusty west winds reached 74 MPH on one of our Maximum, Inc. instruments, 65 MPH on the Aerovane and 62 MPH on ASOS and our 420C official manual observation recorder at 3:20 a.m. this morning. Temperatures fell rapidly from near 32 degrees very early this morning to 15 degrees by 8 a.m. Any slush or water left over from yesterday's snow changing to rain froze quickly. The strong winds and falling temperatures followed in the wake of an intense coastal low pressure system the center of which passed just to our east early last evening. The lowest barometric pressure was close to 28.91 inches at 6:45 p.m. Northeast wind gusted up to 54 MPH ahead of the strong storm system Sunday afternoon. Today's observations: 7 A.M. Weather: Scattered stratocumulus, altocumulus Temperature: 16F, Dew point: 6F, Wind: W at 17G33 kts Wind: peak wind W @ 49 kts @ 5:57 a.m. wind variable WSW-WNW Sea-level pressure: 29.42 inches Hg, rising rapdily Visibility: 45 miles 6-hour min temp: 16F 24-hour precip: 1.32 ins. 24-hour snowfall: 5.5 ins. Snow on ground: 12 inches BHO SA 1155 30 SCT 80 SCT 45 976/16/6/2717G33/942/ PTCHS OF ACSL VIRGA DSNT SW-W PK WND 2649/1057/ WND 24V30 PRESRR TOTAL NEW SNW PST 24 HRS 5.5 INS/ 8/540 51063 4/012 ASOS 70126 MANUAL 70132 10032 20016 10 A.M. Weather: Clear, few distant stratocumulus Temperature: 18F, Dew point: 5F, Wind: W at 26G33 kts Wind: peak wind: W @ 40 kts @ 8:57 a.m.; wind variable WSW-WNW Sea-level pressure: 29.59 inches Hg, rising Visibility: 70 miles BHO SA 1455 CLR 70 021/18/5/2726G33/959/ FEW SC ALQDS PK WND 2840/1357/ WND 24V30/ 8/500 51045 1 P.M. Weather: Clear, stratocumulus distant W-N-ESE Temperature: 22F, Dew point: 6F, Wind: W at 23G34 kts Wind: peak wind: W @ 38 kts @ 12:08 p.m.; variable wind: WSW-WNW Sea-level pressure: 29.67 inches Hg, rising Visibility: 70 miles 6-hourly max. temp: 23F BHO SA 1755 CLR 70 046/22/6/2723G34/967/ FEW SC DSNT WNW-N-ESE PK WND 2738/08/ WND 24V30 52025 10023 20015 WEATHER SUMMARY FOR SUNDAY, DECEMBER 16 TEMPERATURE (DEGREES F) MAX.....43 NORMAL.....38 MIN.....23 NORMAL.....24 MEAN....33 NORMAL.....31 DEPARTURE FROM 30-YEAR NORMAL...........+2 TOTAL DEPARTURE FOR THE MONTH..........-99 [-6.4 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............32 DEPARTURE.......-2 TOTAL HEATING UNITS FOR THE MONTH...........606 DEPARTURE.....+103 TOTAL HEATING UNITS FOR THE SEASON.........1686 DEPARTURE.....-106 TOTAL HEATING UNITS LAST SEASON TO DATE....1456 DIFFERENCE....+230 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............54 NE AT 1:32 P.M. AEROVANE.............52 NE AT 1:32 P.M. ASOS.................53 NE AT 1:32 P.M. DAVIS................52 NE AT 1:32 P.M. FASTEST MILE FOR YESTERDAY..............N/A MAXIMUM 2-MINUTE ASOS AVERAGE...........37 ENE AT 10:00 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........36 ENE AT 9:55 A.M. AVERAGE WIND SPEED AND DIRECTION......21.5 ENE ASOS...............20.1 DAVIS..............20.6 ENE [060 deg] * Last of several occurrences PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....1.32 DEPARTURE....+1.18 ASOS..............1.26 TOTAL PRECIPITATION FOR THE MONTH..........3.72 DEPARTURE....+1.37 ASOS..............3.83 TOTAL PRECIPITATION FOR THE YEAR..........42.56 DEPARTURE....-6.45 ASOS.............42.05 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........5.5 DEPARTURE.....+5.1 TOTAL SNOWFALL FOR THE MONTH...............20.6 DEPARTURE....+15.9 TOTAL SNOWFALL FOR THE SEASON..............21.4 DEPARTURE....+13.8 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 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/-2/0.02/0.2/38/7 28 WSW 12/15 28/15/22/-9/0/0/.../.. N/A 12/16 43/23/33/+2/1.62/8.5/000/00 54 NE 12/17 morning low temp: 15F; normal low now 23F 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 17 HIGH 63 IN 2000 LOW -10 IN 1942 PRECIP 3.03 INS. IN 1888 SNOWFALL 7.5 INS. IN 1988 PEAK GUST 78 MPH SSE IN 2000 RECORDS FOR DECEMBER 18 HIGH 59 IN 1928 LOW -11 IN 1919 PRECIP 1.44 INS. IN 1915 SNOWFALL 7.0 INS. IN 1904 PEAK GUST 76e W IN 1978 TODAY'S REPORT PREPARED By: Robert Skilling