BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, APRIL 17, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Today's weather observations: 7 A.M. Weather: Thin broken cirrus, patches dense cirrus Temperature: 43F, Dew point: 27F, Wind: W at 10 kts Sea-level pressure: 30.24 inches Hg, rising Visibility: 40 miles 6-hour minimum temperature: 35F BHO SA 1155 200 SCT 250 –BKN 40 242/43/27/2810/024/ PTCHS DENS CI THN K LYR ALNG HRZN ALQDS XCPT S-SE/ 8/002 53004 10043 20035 10 A.M. Weather: Clear, few cirrus Temperature: 58F, Dew point: 20F, Wind: W at 8 kts, Wind: Direction variability SW to NNW Sea-level pressure: 30.20 inches Hg, falling Visibility: 60 miles BHO SA 1455 CLR 60 226/58/20/2708/020/ FEW CI WND 23V34/ 8/001 58016 1 P.M. Weather: Clear, few cirrus, halo Temperature: 65F, Dew point: 21F, Wind: W at 12G20 kts Sea-level pressure: 30.10 inches Hg, falling Visibility: 65 miles 6-hourly max. temp: 65F BHO SA 1755 CLR 65 193/65/21/2612G20/010/ FEW CI HALO/ 8/001 56033 10065 20043 WEATHER SUMMARY FOR THURSDAY, APRIL 16, 2009 TEMPERATURE (DEGREES F) MAX.....50 NORMAL......56 MIN.....34 NORMAL......37 MEAN....42 NORMAL......46 DEPARTURE FROM 30-YEAR NORMAL..................-4 TOTAL DEPARTURE FOR THE MONTH..................+5 [+0.1 DEGREE/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............23 DEPARTURE........+4 TOTAL HEATING UNITS FOR THE MONTH............334 DEPARTURE........-5 TOTAL HEATING UNITS FOR THE SEASON..........5752 DEPARTURE.......-51 TOTAL HEATING UNITS LAST SEASON TO DATE.....5458 DIFFERENCE.....+294 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............29 NNE AT 9:41 A.M. AEROVANE.............24 NNE AT 9:41 A.M. * ASOS.................26 NE AT 9:41 A.M. DAVIS................26 N AT 7:45 A.M. FASTEST MILE FOR YESTERDAY..............19 N AT 7:45 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........18 NE AT 9:42 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........19 N AT 7:59 A.M. AVERAGE............11.2 N ASOS...............10.4 DAVIS..............10.6 NNE [032 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...........3.23 DEPARTURE.........+0.83 ASOS...............3.28 TOTAL PRECIPITATION FOR THE YEAR...........13.31 DEPARTURE.........-2.72 ASOS..............14.41 # # Includes erroneous ASOS precipitation data on 1/1/09, 1/2/09 and 2/27/09. SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.........-0.1 TOTAL SNOWFALL FOR THE MONTH................0.2 DEPARTURE.........-1.3 TOTAL SNOWFALL FOR THE SEASON..............78.9 DEPARTURE........+20.3 PRELIMINARY CLIMATE SUMMARY FOR APRIL 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 4/1 43/31/38/-3/0.13/0/015/02 24 SE 4/2 52/39/46/+4/0.02/0/000/00 20 SSE 4/3 58/45/52/+10/0.70//000/00 39 SSE AERO 38 MPH SSE TSTM 4/4 51/38/45/+3/0.01/0/015/02 48 WSW AERO 48 MPH WSW 4/5 58/37/48/+5/0/0/551/71 40 W AERO 37 MPH W 4/6 55/38/47/+4/1.42/0/047/006 42 SE AER0 40 MPH SE TSTM 4/7 50/34/42/-1/T/0/109/14 36 WSW AERO 35 MPH WSW 4/8 45/32/39/-5/0/0/149/19 33 SW AERO 31 MPH SW 4/9 60/34/47/+3/0/0/692/88 36 SSW AERO 33 MPH SSW 4/10 65/41/53/+9/0.18/0/544/69 37 SSW AERO 35 MPH SSW 4/11 44/33/39/-6/0.77/0.2/000/00 35 N AERO 30 MPH N 4/12 43/29/36/-9/0/0/541/68 45 NW AERO 43 MPH WNW 4/13 52/29/41/-4/0/0/734/92 38 W AERO 35 MPH W 4/14 58/37/48/+2/0/0/696/87 25 E 4/15 49/36/43/-3/0/0/.../.. 35 NE AERO 31 MPH NE 4/16 50/34/42/-4/0/0/.../.. 29 NNE AERO 24 MPH NNE 4/17 morning low temp: 35F; our normal low is now 38F NEW DAILY RECORDS FOR APRIL 2009... None to date.. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 17 HIGH 93 IN 2002 LOW 21 IN 1908 PRECIP 1.68 IN 1954 SNOWFALL 1.0 IN. IN 1899 PEAK GUST 58 MPH NW IN 1994 RECORDS FOR APRIL 18 HIGH 92 IN 1976 LOW 23 1887 PRECIP 1.48 IN 1954 SNOWFALL 3.7 IN. IN 1965 PEAK GUST 59 MPH S IN 1982 TODAY'S REPORT PREPARED BY: Stephanie Radner