BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, SEPTEMBER 12, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME COOL, RAINY AND FOGGY TODAY...HEAVY RAIN SHOWERS BRING FIRST MEASURABLE RAIN IN TWO WEEKS AND A BRIEF THUNDERSTORM THIS MORNING... The temperature has remained in the low 60s for the past 24 hours, and the rainfall, which began Friday evening, has accumulated to 1.83 inches as of 2 PM EDT today. The have been several periods of heavy rain since yesterday. In addition there was a brief thunderstorm this morning from 9:25-9:40 AM EDT. Much heavier rain, amounting to 3-4 inches has fallen on the South Shore to the east of the hill since yesterday. This is the first rain since 1.80 inches was measured on August 28-29th. The wind has been remarkably steady lately with the wind direction remaining NE all day Friday until it backed to NNE this morning, and hourly wind speeds have held between 13-17 mph from late Thursday through mid-day today. FROM THE RECORD BOOKS... HURRICANE DONNA STRIKES NEW ENGLAND 49 YEARS AGO TODAY... One of the strongest hurricanes to hit New England in the 20th century made landfall on this date in 1960. It brought a rainfall total of 2.79 inches as the storm passed to the west through Worcester County. The peak gust from this storm, 140 mph SSE, is the second highest gust ever recorded at the Observatory. Today's observations: 7 A.M. Weather: Sky obscured in light rain, light drizzle and fog Temperature: 61F, Dew point: 61F, Wind: NNE at 16G26 kts Wind: Variable direction N to ENE Wind: Peak gust 30 mph NNW at 6:55 AM Sea-level pressure: 30.05 inches Hg, falling Visibility: 1/8 mile, dense fog 6-hour minimum temp: 61F 24-hour precipitation: 1.15 inches BHO SA 1155 W2 X 1/8R-L-F 175/61/61/0316G26/005/ PK WND 0326/55 WND 35V06/ 8//// 58003 60/// 70115 10061 20061 10 A.M. Weather: Sky obscured in light rain, light drizzle and fog heavy rain ended past hour Temperature: 61F, Dew point: 61F, Wind: NNE at 13G21 kts Wind: Variable direction N to ENE Sea-level pressure: 30.03 inches Hg, falling Visibility: 1/8 mile, dense fog 3-hour precipitation: 0.63 inch BHO SA 1455 W2 X 1/8R-L-F 171/61/61/0313G21/003/ R+E48 WND 36V06/ 8//// 58004 6063/ 1 P.M. Weather: Sky obscured in light drizzle and fog Temperature: 62F, Dew point: 62F, Wind: NNE at 11G20 kts Wind: Varible direction N to ENE Sea-level pressure: 29.99 inches Hg, falling Visibility: 1/16 mile, dense fog 6-hour max. temp: 63F 6-hour precipitation: 0.68 inch BHO SA 1755 W1 X 1/16L-F 156/62/62/0311G20/999/ WND 36V06/ 8//// 56015 6068/ 10063 20060 WEATHER SUMMARY FOR FRIDAY, SEPTEMBER 11 TEMPERATURE (DEGREES F) MAX.....61 NORMAL.....73 MIN.....54 NORMAL.....55 MEAN....58 NORMAL.....64 DEPARTURE FROM 30-YEAR AVERAGE...........-6 TOTAL DEPARTURE FOR THE MONTH...........-20 [-2.0 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............7 DEPARTURE.......+4 TOTAL HEATING UNITS FOR THE MONTH............30 DEPARTURE.......+2 TOTAL HEATING UNITS FOR THE SEASON...........64 DEPARTURE.......+5 TOTAL HEATING UNITS LAST SEASON TO DATE......25 DIFFERENCE.....+39 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............30 NE AT 7:09 P.M. AEROVANE..............30 NE AT 3:47 P.M. ASOS..................29 ENE AT 3:46 P.M. DAVIS................ 30 NE AT 7:49 P.M. FASTEST MILE FOR YESTERDAY...............21 NE AT 12:31 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............21 ENE AT 12:31 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........22 NE AT 12:31 P.M. AVERAGE WIND SPEED AND DIRECTION.......14.7 NE ASOS................13.8 DAVIS...............14.2 NE [046 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....1.15 DEPARTURE....+1.01 ASOS..............1.17 TOTAL PRECIPITATION FOR MONTH..............1.15 DEPARTURE....-0.32 ASOS..............1.17 TOTAL PRECIPITATION FOR THE YEAR..........35.92 DEPARTURE....+0.98 ASOS.............37.09 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 3 ENE 9/11 61/54/58/-6/.../0/0 30 NE 9/12 morning low temp: 60F; the normal low is now 54F 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 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) RECORDS FOR SEPTEMBER 13 HIGH 91F IN 1957 LOW 40F IN 1985 PRECIP 3.10 INCHES IN 1987 PEAK GUST 44 MPH WNW IN 1986 TODAY'S REPORT PREPARED BY: Mike Iacono