BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, JANUARY 17, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME BRIGHT SUNSHINE BUT FRIGID TEMPERATURES AGAIN TODAY... After a high and low temperature of 17 and 0 on Friday, this morning's low was 1 degree. The mean wind speed of 12 mph at 7 AM today and the air temperature of 1 combined to create a wind chill of -16 deg F. A fairly strong inversion was in place again this morning with a low temperature at the nearby Norwood Airport of -10 deg F this morning. The air remains very dry today with the dew point in the -5 to -10 deg F range. Friday's low temperature of 0 was the coldest of the season to date, and it was the coldest temperature since -1 on January 26, 2007. January is now averaging about 4 degrees colder than normal per day. The depth of old snow on the summit remains 7 inches. 7 A.M. Weather: Clear, stratocumulus NE-SE along/offshore, few stratocumulus SE-SSW, few altocumulus N Temperature: 1F, Dew point: -9F, Wind: WSW at 10 kts Sea-level pressure: 30.50 inches Hg, rising Visibility: 40 miles 6-hour minimum temperature: 1F Snow depth on ground: 7 inches BHO SA 1155 CLR 40 329/1/-9/2410/050/ SC MDT CUFRM TOPS OFFSHR NE-SE FEW SC SE-SSW FEW AC N/ 8/530 4/007 51010 10003 20001 10 A.M. Weather: Thin scattered cirrus, stratocumulus NE-ESE along/offshore,thin smoke layer SW-NE Temperature: 9F, Dew point: -5F, Wind: SW at 6 kts Sea-level pressure: 30.53 inches Hg, rising Visibility: 40 miles BHO SA 1455 250 –SCT 40 337/9/-5/2206/053/ FEW SC OFFSHR NE-ESE THN K LYR ALG HRZN SW-NE WND LGT/ 8/501 51008 1 P.M. Weather: Thin scattered cirrus, few stratocumulus distant S-SSW Temperature: 16F, Dew point: -6F, Wind: SW at 9 kts Sea-level pressure: 30.44 inches Hg, falling Visibility: 40 miles 6-hour maximum temperature: 16F BHO SA 1755 250 –SCT 40 308/16/-6/2309/044/ FEW SC DSNT S-SSW/ 8/501 58029 10016 20001 WEATHER SUMMARY FOR FRIDAY, JANUARY 16 TEMPERATURE (DEGREES F) MAX.....17 NORMAL.....34 MIN......0 NORMAL.....18 MEAN.....9 NORMAL.....26 DEPARTURE FROM 30-YEAR NORMAL..............-17 TOTAL DEPARTURE FOR THE MONTH..............-65 [-4.3 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............56 DEPARTURE........+17 TOTAL HEATING UNITS FOR THE MONTH............684 DEPARTURE........+66 TOTAL HEATING UNITS FOR THE SEASON..........2924 DEPARTURE........-23 TOTAL HEATING UNITS LAST SEASON TO DATE.....2667 DIFFERENCE......+257 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............26 W AT 2:50 P.M. AEROVANE.............24 W AT 2:50 P.M. ASOS.................25 W AT 2:50 P.M. DAVIS................26 W AT 2:49 P.M. FASTEST MILE FOR YESTERDAY..............20 W AT 2:55 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........20 W AT 2:56 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........18 W AT 2:56 P.M. AVERAGE.............11.7 W ASOS................11.6 DAVIS...............10.0 WSW [250 deg] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.....0.00 DEPARTURE.........-0.16 ASOS...............0.00 TOTAL PRECIPITATION FOR THE MONTH...........2.04 DEPARTURE.........-0.44 ASOS...............3.02 # TOTAL PRECIPITATION FOR THE YEAR............2.04 DEPARTURE.........-0.44 ASOS...............3.02 # # Includes erroneous ASOS precipitation data on 1/1/09 and 1/2/09 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.........-0.5 TOTAL SNOWFALL FOR THE MONTH................7.6 DEPARTURE.........-0.4 TOTAL SNOWFALL FOR THE SEASON..............38.0 DEPARTURE........+16.4 PRELIMINARY CLIMATE SUMMARY FOR JANUARY 2009 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system gust when significant TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 1/1 16/1/9/-18/0/0/538/98 44 WNW Aero 44 MPH WNW 1/2 32/9/21/-6/0/0/005/01 28 S 1/3 32/21/27/0/T/T/539/98 43 WNW Aero 44 MPH WNW 1/4 35/17/26/-1/0/0/512/93 36 W Aero 33 MPH W 1/5 36/26/31/+4/0.06/0/512/93 30 W 1/6 33/21/27/+1/0/0/183/33 27 W 1/7 36/26/31/+5/1.26/0.8/000/00 46 NE Aero 45 MPH NE 1/8 38/21/30/+4/0.01/0.1/389/70 47 W Aero 45 MPH W 1/9 25/16/21/-5/0/0/546/98 37 W Aero 36 MPH W 1/10 24/11/18/-8/0.10/1.0/329/59 28 W 1/11 31/19/25/-1/0.55/5.3/000/00 30 NW 1/12 27/18/23/-3/0.02/0.4/410/73 24 WNW 1/13 34/16/25/-1/0.04/T/107/19 25 SE 1/14 33/10/22/-4/0/0/518/92 47 W 1/15 16/5/11/-15/0/0/000/00 20 NW 1/16 17/0/9/-17/0/0/.../.. 26 W 1/17 morning low temp: 1F; our normal low is now 18F NEW DAILY RECORDS FOR JANUARY 2009... ..NONE.. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR JANUARY 17 HIGH 55F IN 1973,1995 LOW -8F IN 1907,1982 PRECIP 1.43 INS. IN 1956 SNOWFALL 13.4 INS. IN 1956 PEAK GUST 62 MPH S IN 1994 RECORDS FOR JANUARY 18 HIGH 62F IN 1973,1990 LOW -10F IN 1982 PRECIP 1.68 INS. IN 1915 SNOWFALL 13.0 INS. IN 1948 PEAK GUST 85 MPH SSE IN 2006 TODAY'S REPORT PREPARED By: Mike Iacono