BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, SEPTEMBER 8, 2008 ALL TIMES ARE IN EASTERN STANDARD TIME UNLESS NOTED Today's observations: TROPICAL STORM HANNA BRINGS PEAK WIND GUSTS TO 44 MPH SE AND 43 MPH NW WITH A TOTAL RAINFALL OF 2.19 INCHES (all times below are in Eastern Daylight Time) The passage of the broad center of Tropical Storm HANNA during the early morning hours of September 7 brought a period of calm wind between 2:45 and 2:52 A.M. As Hanna approached from the southwest, southeast winds gusted to 44 MPH just after midnight at 12:07 A.M. on September 7. The lowest barometric pressure of 29.44 inches was recorded by ASOS at 2:44 A.M. Peak wind gusts after the center's passage were 43 MPH from the northwest at 3:47, 4:19 and 4:21 A.M. Fastest 2-minute winds were 29 MPH SE at 12:10 A.M. and 28 MPH NW at 4:20 A.M. Dew point temperatures rose to at least 73-75F during the afternoon and evening of September 6. A band of heavy rainfall arrived well in advance of Hanna on Saturday morning, September 6, and a total 0.47 inch was recorded by 8 A.M. Later, during the afternoon and evening, tropical downpours produced some heavy amounts of rain. The maximum amount in any 60 minutes was 0.42 inch ending at 11 P.M. EDT. The maximum calendar day amount was 1.90 inches on September 6 and greatest in 24 hours 2.15 inches on the 6th-7th. The storm total was 2.19 inches, the most on any one day since 2.27 inches on July 24. 8 A.M. EDT Weather: Clear Temperature: 61F, Dew point: 54F, Wind: W at 10 kts Sea-level pressure: 30.13 inches Hg, rising Visibility: 55 miles 6-hourly minimum temperature: 58F 24-hourly rainfall: 0.00 inches BHO SA 1155 CLR 55 203/61/54/2710/013/ 53020 10061 20058 11 A.M. EDT Weather: Clear, few cumulus forming distant NW, few cirrus distant SSE Temperature: 70F, Dew point: 53F, Wind: W at 8 kts Sea-level pressure: 30.16 inches Hg, falling Visibility: 60 miles, NW 70 miles BHO SA 1455 CLR 60 212/70/53/2608/016/ FEW CU DSNT NW FEW CI DSNT SSE VSBY NW 70/ 8/101 50009 2 P.M. EDT Weather: Clear with few small cumulus and few cirrus Temperature: 76F, Dew point: 53F, Wind: W at 5 kts Sea-level pressure: 30.14 inches Hg, falling Visibility: 65 miles, NW 75 miles 6-hour max. temp: 76F BHO SA 1755 CLR 65 207/76/53/2605/014/ FEW SML CU FEW CI VSBY NW 75/ 8/101 56005 10076 20061 WEATHER SUMMARY FOR SUNDAY, SEPTEMBER 7 TEMPERATURE (DEGREES F) MAX.....78 NORMAL.....74 MIN.....61 NORMAL.....56 MEAN....70 NORMAL.....65 DEPARTURE FROM 30-YEAR NORMAL............+ 5 TOTAL DEPARTURE FOR THE MONTH............+38 (+5.2 PER DAY) PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............43 NW AT 3:21 A.M. * AEROVANE.............43 NW AT 3:21 A.M. * ASOS.................43 NW AT 3:19 A.M. DAVIS................43 NW AT ~3:20 A.M. FASTEST MILE FOR YESTERDAY............. 31 NW AT 3:19 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........28 NW AT 3:20 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........30 NW AT ~3:20 A.M. AVERAGE............14.7 W ASOS...............13.4 DAVIS..............15.4 W [270 deg] * last of several occurrences... ~ time estimated due differences in EST/EDT with Davis system PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE.......-0.13 ASOS..............0.00 TOTAL PRECIPITATION FOR SEPT..............2.19 DEPARTURE.......+1.28 ASOS..............2.21 TOTAL PRECIPITATION FOR THE YEAR..........37.65 DEPARTURE.......+3.27 ASOS.............40.21 # # 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 86/67/77/+12/0.00/.../.. 32 SSE 9/6 82/68/75/+10/.../.../.. 44 SE Aero 39 MPH SE * 9/7 78/61/70/+5/.../.../.. 43 NW Aero 43 MPH NW * * Tropical Storm Hanna 9/8 morning low temp. 58F; 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 8 HIGH 93F IN 2007 LOW 42F IN 1978 PRECIP 0.74 INCHES IN 1888 PEAK GUST 40e MPH NW IN 1941, WSW IN 1944 RECORDS FOR SEPTEMBER 9 HIGH 91F IN 2002 LOW 41F IN 1938 PRECIP 1.97 INCHES IN 1969 PEAK GUST 52 MPH WNW IN 1969, NW IN 1978 TODAY'S REPORT PREPARED By: Robert Skilling