BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SUNDAY, FEBRUARY 25, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME ARCTIC AIRMASS SLOWLY LOSING ITS GRIP SINCE LATE YESTERDAY HIGH CLOUD LAYER SLOWLY ADVANCING FROM THE SOUTHWEST The Arctic airmass that began arriving Friday afternoon and evening produced its coldest day yesterday averaging 8 degrees colder than average. However, this latest mass of frigid air turned out to be quite a bit less harsh than the several earlier ones this month. Between February 4th and 19th there were three much colder seperate episodes averaging between 10 and 16 degrees colder than average on eight days. The sun was observed rising into a clear sky at 6:25 a.m. this morning and under the strong late February sunshine temperatures are rising steadily into the 30's with only gentle WNW winds. A layer of high clouds can be seen slowly advancing from off to our southwest ahead of the extensive precipitation producing system centered this morning in the Missouri Valley. Today's observations: 7 A.M. Weather: Clear, high clouds distant S-SW Temperature: 20F, Dew point: 11F, Wind: WNW at 10 kts Sea-level pressure: 30.10 inches Hg, rising Visibility: 80 miles 6-hourly min. temp. 19 deg. Snow on ground: 1 inch BHO SA 1155 CLR 80 193/20/11/2810/010/ CS LYR ALG HRZN DSNT S-SW/ 8/008 4/001 51006 10023 20019 10 A.M. Weather: Clear, high cloud layer SSE-W slowly advancing toward us Temperature: 31F, Dew point: 14F, Wind: WNW at 10 kts Sea-level pressure: 30.10 inches Hg, falling Visibility: 80 miles BHO SA 1455 CLR 80 192/31/14/2910/010/ CS LYR XTDNG SSE-W SLWLY ADVCNG WND 26V32/ 8/005 58001 WEATHER SUMMARY FOR SATURDAY, FEBRUARY 24 TEMPERATURE (DEGREES F) MAX.....33 NORMAL.....38 MIN.....11 NORMAL.....22 MEAN....22 NORMAL.....30 DEPARTURE FROM 30-YEAR NORMAL..........-8 TOTAL DEPARTURE FOR THE MONTH........-125 (-5.4 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..........43 DEPARTURE........+8 TOTAL HEATING UNITS FOR THE MONTH........1017 DEPARTURE......+120 TOTAL HEATING UNITS FOR THE SEASON.......3961 DEPARTURE......-472 TOTAL HEATING UNITS LAST SEASON TO DATE..3901 DIFFERENCE......+60 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............40 WNW AT 7:44 A.M. * AEROVANE.............43 WNW AT 7:44 A.M. * ASOS.................41 WNW AT 7:44 A.M. DAVIS................43 WNW AT 7:43 A.M. FASTEST MILE FOR YESTERDAY..............35 WNW AT 7:44 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE...........35 WNW AT 7:44 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........36 WNW AT 7:44 A.M. AVERAGE WIND SPEED AND DIRECTION......20.3 WNW ASOS..............20.0 DAVIS.............20.7 WNW [290 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..........2.47 DEPARTURE.....-0.99 ASOS..............2.45 TOTAL PRECIPITATION FOR THE YEAR...........5.41 DEPARTURE.....-2.83 ASOS..............5.32 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE......-0.5 TOTAL SNOWFALL FOR THE MONTH................3.8 DEPARTURE.....-10.2 TOTAL SNOWFALL FOR THE SEASON..............10.4 DEPARTURE.....-33.0 PRELIMINARY CLIMATE SUMMARY FOR FEBRUARY 2007......CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available 2/1 35/20/28/+2/0/0/126/21 37 S Aero 34 MPH S 2/2 35/28/32/+6/0.18/0.3/000/00 20 NW 2/3 32/19/26/0/0.05/0.4/574/95 39 W Aero 47 MPH W 2/4 22/10/16/-10/0/0/601/99 39 WSW Aero 40 MPH WSW 2/5 16/5/11/-16/0/0/493/81 61 W Aero 60 MPH W 2/6 24/10/17/-10/0/0/593/97 38 W Aero 36 MPH W 2/7 21/8/15/-12/0/0/474/77 43 W Aero 41 MPH W 2/8 25/11/18/-9/0/0/370/60 48 WSW 2/9 26/15/21/-6/0/0/600/97 44 WSW Aero 42 MPH WSW 2/10 32/13/23/-4/0/0/199/32 28 W 2/11 31/14/23/-4/0/0/456/73 27 SSW 2/12 36/20/28/0/0/0/602/96 43 WSW Aero 40 MPH W 2/13 22/6/14/-14/0.02/0.2/226/36 28 NW 2/14 36/13/25/-3/2.09/1.4/000/00 47 NE Aero 52 MPH NE 2/15 21/9/15/-13/0/0/616/97 46 W Aero 53 MPH W 2/16 27/9/18/-10/0/0/624/98 51 W Aero 49 MPH W 2/17 34/17/26/-3/0/0/596/93 42 W 2/18 33/16/25/-4/0/0/289/45 38 WNW Aero 40 MPH WNW 2/19 20/5/13/-16/0/0/646/100 46 WNW Aero 51 MPH WNW 2/20 48/17/33/+4/T/0/266/41 35 SSW Aero 34 MPH SSW 2/21 44/30/37/+8/0.01/0/606/93 ** 29 W 2/22 39/28/34/+4/0.02/0.2/007/01 22 SSE 2/23 32/14/23/-7/0.10/1.3/.../.. 55 WNW Aero 56 MPH WNW 2/24 33/11/22/-8/0/0/652/99 40 WNW Aero 43 MPH WNW ** precip. for 2/21 corrected to read 0.01 in.; corrected from zero 2/25 morning low temp. 19 deg; normal now 22 deg. there is still one inch of average snow cover on the ground with many bare spots 2/14 - NEW RECORD DAILY PRECIPITATION OF 2.09 INCHES; the previous record was 1.95 inches in 1940. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR FEBRUARY 25 HIGH 67F IN 1976 LOW -10F IN 1894 PRECIP 2.40 INCHES IN 1981 SNOWFALL 13.6 INCHES IN 1966 PEAK GUST 75 MPH S IN 1965 RECORDS FOR FEBRUARY 26 HIGH 67F IN 1957 LOW -7F IN 1928 PRECIP 2.24 INCHES IN 1979 SNOWFALL 11.1 INCHES IN 1933 PEAK GUST 66 MPH W IN 1961 TODAY'S REPORT By: Robert Skilling