BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 5, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME OBSERVATORY ANNUAL OPEN HOUSE TODAY... PARTLY SUNNY, WARM AND DRY WEATHER TODAY... The annual Spring Open House at Blue Hill Observatory is being held from 10 a.m. to 4 p.m. today at the summit. Early morning sunshine has changed to thin overcast cirrus by late morning, though the temperature has climbed to the low 60s. The air is very dry once again with the dew point in the upper teens. The visibility is very high today at about 75-80 miles. Today's observations: 7 A.M. Weather: Thin scattered cirrus Temperature: 52F, Dew point: 25F, Wind: WNW at 9 kts Sea-level pressure: 30.14 inches Hg, steady Visibility: 70 miles 6-hour min. 45F BHO SA 1155 300 –SCT 70 205/52/25/2909/014/ FEW LWR CI THN K LYR ALG HRZN NNW-NE/ 8/001 54000 10052 20045 10 A.M. Weather: Scattered cirrus, overcast cirrus Temperature: 63F, Dew point: 19F, Wind: WNW at 12 kts Sea-level pressure: 30.11 Hg, falling Visibility: 75 miles BHO SA 1455 200 SCT E250 OVC 75 195/63/19/3012/011/ THN SPTS IOVC ALQDS CLRNG ALG HZN SW-SE SUN VSBL/ 8/008 56010 WEATHER SUMMARY FOR FRIDAY, MAY 4 TEMPERATURE (DEGREES F) MAX.....66 NORMAL.....63 MIN.....44 NORMAL.....43 MEAN....55 NORMAL.....53 DEPARTURE FROM 30-YEAR NORMAL...........+2 TOTAL DEPARTURE FOR THE MONTH..........+11 (+3.0 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY...........10 DEPARTURE.........-2 TOTAL HEATING UNITS FOR THE MONTH...........39 DEPARTURE........-12 TOTAL HEATING UNITS FOR THE SEASON........5655 DEPARTURE.......-422 TOTAL HEATING UNITS LAST SEASON TO DATE...5478 DIFFERENCE......+177 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............39 WNW AT 1:13 P.M. AEROVANE.............40 WNW AT 1:11 P.M. ASOS.................38 WNW AT 1:11 P.M. DAVIS................40 WNW AT 1:10 P.M. FASTEST MILE FOR YESTERDAY..............32 WNW AT 1:11 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........30 WNW AT 1:12 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........31 WNW AT 1:14 P.M. AVERAGE WIND SPEED AND DIRECTION........15.2 NW ASOS................14.2 DAVIS...............15.5 WNW [303 degrees] 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 THE MONTH..........0.06 DEPARTURE....-0.46 ASOS..............0.04 TOTAL PRECIPITATION FOR THE YEAR..........20.48 DEPARTURE....+2.01 ASOS.............20.01 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.......0.0 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE......-0.1 TOTAL SNOWFALL FOR THE SEASON..............27.6 DEPARTURE.....-32.5 PRELIMINARY CLIMATE SUMMARY FOR MAY 2007......CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available 5/1 67/44/56/+4/0/0/624/74 33 NW 5/2 64/45/55/+3/0.06/0/381/45 36 NW Aero 33 MPH WNW 5/3 67/42/55/+2/0/0/849/100 38 W Aero 37 MPH W 5/4 66/44/55/+2/0/0/.../.. 39 WNW 5/5 morning low temp. 44 deg; normal now 43 deg. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 5 HIGH 92F IN 1949 LOW 30F IN 1891 PRECIP 2.74 INCHES IN 1922 SNOWFALL 3.0 INCHES IN 1917 PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976 RECORDS FOR MAY 6 HIGH 90F IN 1930 LOW 29F IN 1891 PRECIP 1.04 INCHES IN 1890 SNOWFALL TRACE IN 1917,1996 PEAK GUST 65 MPH SSE IN 1989 TODAY'S REPORT PREPARED By: Mike Iacono