BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, SEPTEMBER 6, 2008 ALL TIMES ARE IN EASTERN STANDARD TIME UNLESS NOTED RAIN BAND WELL IN ADVANCE OF T.S. HANNA EARLY TODAY PURE TROPICAL AIRMASS TODAY WITH DEW POINTS RISING INTO THE LOW AND MIDDLE 70'S Tropical Storm Hanna was tracking northward and turning to the northeast as the center moved through eastern North Carolina and southeast Virginia this morning headed up along the Middle Atlantic coast. A heavy rain band well in advance of the storm brought a burst of moderate to heavy rain here between 4 and 7 a.m. EDT with a total of 0.47 measured through 8 a.m. This was our first precipitation event of September to date and really the first significant rainfall since 1.32 inches fell on August 15th. Before this morning's rain the total rainfall had been only 0.09 inch since mid-August. A very humid tropical air mass began arriving ahead of Hanna this morning on south-southeast winds with dew points rising to the middle 70's. Today's observations: 8 A.M. EDT Weather: Broken stratocumulus, overcast altocumulus, few stratus fractus drifting over and below summit, dense fog dissipated past hour, rain ended 30 past the hour, very light rain shower began 50 ended 53 past the hour Temperature: 71F, Dew point: 71F, Wind: SSE at 10 kts Sea-level pressure: 30.00 inches Hg, steady Visibility: 15 miles, N 8, thin fog all directions 6-hourly minimum temperature: 68F 24-hourly rainfall: 0.47 BHO SA 1155 E50 BKN 65 OVC 15 159/71/71/1610/000/ FEW STFRA DRFTG OVR BLO/SMT FEW SCC/ACC HIER CLDS VSB SSE DENS FG DSSPTG PST HR VSBY N 8 RE30B50E53/ 8/68/ 56007 MANUAL 6047/ ASOS 60048 MANUAL 70047 ASOS 70048 10070 20069 11 A.M. EDT Weather: Low overcast stratus Temperature: 75F, Dew point: 74F, Wind: SSE at 9 kts Sea-level pressure: 30.00 inches of Hg, steady Visibility: 6 miles in light fog, N-E 15 3-hourly precip: 0.01 inch BHO SA 1455 E3 OVC 6F 159/75/74/1609/000/ VSBY N-E 15 LWRG SE-W/ 8/6/// 58000 ASOS 60001 MANUAL 6001/ 58000 1 P.M. EDT Weather: Broken variable overcast stratocumulus with broken altocumulus and cirrus Temperature: 80F, Dew point: 75F, Wind: S at 12 kts Sea-level pressure: 29.97 ins. Hg, falling Visibility: 20 miles, hazy 5-hourly max. temp. 81F 5-hourly rainfall: 0.01 in. BHO SA 1655 E12V BKN 150 SCT 250 BKN 20 148/80/75/1812/997/ SC MDT CUFRM TOPS 12 BKN V OVC HAZY/ 8/541 WEATHER SUMMARY FOR FRIDAY, SEPTEMBER 5 TEMPERATURE (DEGREES F) MAX.....86 NORMAL.....74 MIN.....67 NORMAL.....57 MEAN....77 NORMAL.....65 DEPARTURE FROM 30-YEAR NORMAL............+12 TOTAL DEPARTURE FOR THE MONTH............+23 (+4.4 PER DAY) PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............32 SSE AT 2:08 P.M. AEROVANE.............32 SSE AT 2:08 P.M. ASOS.................32 SSE AT 2:40 P.M. DAVIS................35 S AT 3:10 P.M. FASTEST MILE FOR YESTERDAY............. 24 SSE AT 2:42 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........24 SSE AT 2:43 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........23 S AT 3:12 P.M. AVERAGE.............13.1 S ASOS................12.2 DAVIS...............11.8 S [180 deg] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.47 DEPARTURE.......+0.34 ASOS..............0.48 TOTAL PRECIPITATION FOR SEPT..............0.47 DEPARTURE.......-0.18 ASOS..............0.48 TOTAL PRECIPITATION FOR THE YEAR..........35.93 DEPARTURE.......+1.81 ASOS.............38.48 # # Includes erroneous ASOS precipitation data on 2/13/08. PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 2008 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/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 9/1 81/57/69/+2/0.00/787/100 29 NW 9/2 74/60/67/+1/0.00/604/77 27 N 9/3 75/57/66/0/0.00/766/98 22 N Aero 20 MPH SSE 9/4 85/62/74/+8/0.00/.../.. 23 SSW 9/5 86/67/78/+13/0.00/.../.. 32 SSE 9/6 morning low temp: 68F; our normal low is now 56F NEW DAILY RECORDS FOR SEPTEMBER None to date.. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 6 HIGH 92F IN 1900 LOW 39F IN 1888 PRECIP 3.19 INCHES IN 1890 PEAK GUST 78e MPH SE IN 1979 (TROPICAL STORM DAVID) RECORDS FOR SEPTEMBER 7 HIGH 92F IN 2007 LOW 40F IN 1888 PRECIP 2.95 INCHES IN 1891 PEAK GUST 58e MPH W IN 1941 TODAY'S REPORT PREPARED By: Robert Skilling