BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, OCTOBER 17, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME MOSTLY CLOUDY AND COLD WEATHER CONTINUES... NEW RECORD LOW MAXIMUM TEMPERATURES ON THURSDAY AND FRIDAY...TRACE OF SNOWFALL YESTERDAY... The first frozen precipitation of the season occurred on Friday as snow and sleet mixed with the rainfall early in the morning. This has been accompanied by cold temperatures over the past few days, which included the first freeze of the season on the 14th. The maximum temperature on the 15th of 41 was a new record low maximum for the date, breaking the previous record of 47 in 1887 and 1896. On Friday, the high temperature of 41 was also a new record low maximum, breaking the previous 42 set in 1940. October temperature has dropped to about four degrees colder than average. Today's observations: 7 A.M. Weather: Scattered stratocumulus, thin scattered cirrus Temperature: 35F, Dew point: 31F, Wind: N at 10 kts Sea-level pressure: 30.08 inches Hg, falling Visibility: 35 miles, 50 miles NW, 20 miles NE 6-hour minimum temp: 33F 24-hour precipitation: 0.03 in. BHO SA 1155 40 SCT 250 –SCT 35 186/35/31/3510/008/ VSBY NW 50 NE 20 HAZY/ 8/501 50000 70003 10039 20033 10 A.M. Weather: Scattered stratocumulus, overcast stratocumulus, breaks in overcast W-NE Temperature: 44F, Dew point: 36F, Wind: N at 10 kts Wind: Direction variable NNW to NNE Sea-level pressure: 30.11 inches Hg, rising Visibility: 55 miles, 70 miles NW, 35 miles E-S BHO SA 1455 30 SCT E40 OVC 55 196/44/36/3610/011/ BINOVC W-NE VSBY NW 70 E-S 35 WND33V03/ 8/5// 51010 1 P.M. Weather: Scattered stratocumulus, overcast stratocumulus, breaks in overcast all quadrants Temperature: 46F, Dew point: 37F, Wind: N at 10G22 kts, Wind: Direction variable WNW to NE Sea-level pressure: 30.11 inches Hg, rising Visibility: 70 miles 6-hour maximum temp: 48F BHO SA 1755 25 SCT E40 OVC 70 195/46/37/0110G22/011/ BINOVC ALQDS WND 34V04/ 8/5// 51001 10048 20035 WEATHER SUMMARY FOR FRIDAY, OCTOBER 16 TEMPERATURE (DEGREES F) MAX.....41 NORMAL.....60 MIN.....33 NORMAL.....43 MEAN....37 NORMAL.....51 DEPARTURE FROM 30-YEAR AVERAGE..........-14 TOTAL DEPARTURE FOR THE MONTH...........-61 [-4.0 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............28 DEPARTURE......+14 TOTAL HEATING UNITS FOR THE MONTH...........236 DEPARTURE......+57 TOTAL HEATING UNITS FOR THE SEASON..........393 DEPARTURE......+45 TOTAL HEATING UNITS LAST SEASON TO DATE.....257 DIFFERENCE....+136 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............37 NNE AT 5:05 A.M. * AEROVANE..............35 NNE AT 4:55 A.M. * ASOS..................37 NE AT 3:25 A.M. DAVIS.................34 N AT 5:05 A.M. FASTEST MILE FOR YESTERDAY...............26 NNE AT 4:32 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE............24 NE AT 4:33 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........24 NNE AT 4:33 A.M. AVERAGE WIND SPEED AND DIRECTION.......14.6 N ASOS................14.4 DAVIS...............13.6 N [003 DEG] * Last of several occurrences. PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.03 DEPARTURE....-0.11 ASOS..............0.04 TOTAL PRECIPITATION FOR MONTH..............2.74 DEPARTURE....+0.50 ASOS..............2.75 TOTAL PRECIPITATION FOR THE YEAR..........40.62 DEPARTURE....+0.78 ASOS.............41.81 PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 2009 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust when significant TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 10/1 56/39/48/-9/0/155/22 27 WSW 10/2 60/40/50/-6/0/442/63 23 SSE 10/3 63/51/57/+1/1.10/000/00 32 ESE AERO 30 MPH ESE 10/4 67/57/62/+6/0/202/29 21 WSW 10/5 64/49/57/+2/0/595/86 33 W AERO 31 MPH W 10/6 65/45/55/0/0/628/91 25 W 10/7 67/51/59/+4/0.70/344/50 54 W AERO 54 MPH W 10/8 61/48/55/+1/0/602/88 43 W AERO 39 MPH W 10/9 60/48/54/0/0.05/000/00 29 SSE 10/10 62/42/52/-2/0.26/205/30 37 NW 10/11 61/39/50/-3/0/655/97 35 WSW AERO 33 MPH W 10/12 53/36/45/-8/T/471/70 23 SSW 10/13 51/36/44/-8/0.20/074/11 35 WNW 10/14 52/32/42/-10/0/.../.. 27 NW 10/15 41/32/37/-15/0.19/000/00 29 NNE 10/16 41/33/37/-14/0.24/000/00 37 NNE AERO 35 MPH NNE T SNOW 10/17 morning low temp: 33F; our normal low temp: 42F NEW DAILY RECORDS FOR OCTOBER 2009 10/7: NEW RECORD WIND GUST 54 MPH W AT 2005E; surpasses previous record of 52 MPH ESE in 1972 10/15: NEW RECORD LOW MAXIMUM TEMPERATURE 41; surpasses previous 47 set in 1887 and 1896 10/16: NEW RECORD LOW MAXIMUM TEMPERATURE 41; surpasses previous 42 set in 1940 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR OCTOBER 17 HIGH 86F IN 1947 LOW 25F IN 1886 PRECIP 1.87 INCHES IN 1989 SNOWFALL TRACE IN 1970 PEAK GUST 55 MPH NE IN 1964 RECORDS FOR OCTOBER 18 HIGH 82F IN 1908 LOW 26F IN 1939 PRECIP 2.79 INCHES IN 1975 SNOWFALL TRACE IN 1972 PEAK GUST 66 MPH S IN 1967 TODAY'S REPORT PREPARED BY: Mike Iacono