BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, SEPTEMBER 11, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Today's observations: 7 A.M. Weather: Overcast stratus Temperature: 58F, Dew point: 55F, Wind: NE at 13G23 kts Wind: Variable direction N to E Sea-level pressure: 30.36 inches Hg, falling Visibility: 10 miles, thin fog 6-hour minimum temp: 54F BHO SA 1155 E10 OVC 10 282/58/55/0413G23/036/ THN FG WND 35V08/ 8/6// 58003 10058 20054 10 A.M. Weather: Overcast stratus Temperature: 59F, Dew point: 57F, Wind: NE at 12G22 kts Wind: Variable direction N to E Sea-level pressure: 30.35 inches Hg, falling Visibility: 8 miles, thin fog 3-hour precipitation: Trace BHO SA 1455 E8 OVC 8 277/59/57/0512G22/035/ THN FG WND 01V09 REUKN PCPN VRY LGT/ 8/6// 58005 MANUAL 6000/ 1 P.M. Weather: Overcast stratus Temperature: 61F, Dew point: 58F, Wind: NE at 14G21 kts Wind: Varible direction N to E Sea-level pressure: 30.29 inches Hg, falling Visibility: 8 miles, thin fog 6-hour max. temp: 61F 6-hour precipitation: Trace BHO SA 1755 E6 OVC 8 257/61/58/0514G21/029/ THN FG WND 01V10 REUKN PCPN VRY LGT/ 8/6// 56020 MANUAL 6000/ 10061 20058 WEATHER SUMMARY FOR THURSDAY, SEPTEMBER 10 TEMPERATURE (DEGREES F) MAX.....65 NORMAL.....73 MIN.....53 NORMAL.....55 MEAN....59 NORMAL.....64 DEPARTURE FROM 30-YEAR AVERAGE...........-5 TOTAL DEPARTURE FOR THE MONTH...........-14 [-1.6 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............6 DEPARTURE.......+3 TOTAL HEATING UNITS FOR THE MONTH............23 DEPARTURE.......-2 TOTAL HEATING UNITS FOR THE SEASON...........57 DEPARTURE.......+1 TOTAL HEATING UNITS LAST SEASON TO DATE......19 DIFFERENCE.....+38 * * HDD DEPARTURE FOR THE SEASON WAS INCORRECT ON YESTERDAY'S REPORT (9/10/09) AND HAS BEEN CORRECTED IN THE ARCHIVE. PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............31 ENE AT 9:08 A.M. AEROVANE..............30 NE AT 9:26 A.M. ASOS..................30 ENE AT 8:04 A.M. DAVIS................ 31 NE AT 8:03 A.M. FASTEST MILE FOR YESTERDAY...............23 ENE AT 9:02 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE............22 ENE AT 9:02 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........23 NE AT 9:02 A.M. AVERAGE WIND SPEED AND DIRECTION.......12.8 ENE ASOS................12.0 DAVIS...............12.9 NE [054 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE....-0.14 ASOS..............0.00 TOTAL PRECIPITATION FOR MONTH..............0.00 DEPARTURE....-1.33 ASOS..............0.00 TOTAL PRECIPITATION FOR THE YEAR..........34.77 DEPARTURE....-0.03 ASOS.............35.92 PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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 9/1 71/51/61/-6/0/773/98 17 NW 9/2 76/54/65/-1/0/786/100 22 S 9/3 77/56/67/+1/0/587/75 19 SW 9/4 77/60/69/+3/0/764/98 18 NE 9/5 81/59/70/+5/0/591/76 25 NNW 9/6 64/53/59/-6/0/743/96 31 NNE 9/7 70/52/61/-4/0/709/92 20 WSW 9/8 75/56/66/+1/0/369/48 18 WSW 9/9 68/55/62/-2/0/352/46 36 NNE 9/10 65/53/59/-5/0/603/79 31 ENE 9/11 our morning low temp: 54F; the normal low is now 55F NEW DAILY RECORDS FOR SEPTEMBER 2009 TO DATE... None. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 11 HIGH 93F IN 1983 LOW 37F IN 1917 PRECIP 5.23 INCHES IN 1954 (HURRICANE EDNA) PEAK GUST 101 MPH NW IN 1954 (HURRICANE EDNA) RECORDS FOR SEPTEMBER 12 HIGH 92F IN 1961 LOW 42F IN 1958,1967,1985 PRECIP 2.79 INCHES IN 1960 (HURRICANE DONNA) PEAK GUST 140 MPH SSE IN 1960 (HURRICANE DONNA) TODAY'S REPORT PREPARED BY: Stephanie Radner