BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 16, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Today's observations: 7 A.M. Weather: Broken altocumulus, broken cirrus, few lower altocumulus, hazy Temperature: 56F, Dew point: 52F, Wind: NE at 7 kts Sea-level pressure: 30.22 inches Hg, rising Visibility: 20 miles, 12 miles N-E 6-hour minimum temp: 54F 24-hour precipitation: 0.00 in. BHO SA 1155 E120 BKN 250 BKN 20 233/56/52/0407/022/ FEW LWR AC VSBY N-E 12 HAZY WND LGT/ 8/071 51014 10060 20054 10 A.M. Weather: Scattered altocumulus, thin broken cirrus, few stratocumulus NE, fog bank visible offshore NNE-NE Temperature: 61F, Dew point: 52F, Wind: NE at 7 kts Wind: Direction variable N-ENE Sea-level pressure: 30.19 inches Hg, falling Visibility: 20 miles, hazy BHO SA 1455 120 SCT 250 –BKN 20 225/61/52/0407/019/ FEW SC NE FOG BK OFFSHR NNE-NE HAZY WND 01V07/ 8/671 58004 1 P.M. Weather: Scattered cumulus congestus, scattered altocumulus, thin overcast cirrus, few cumulus fractus, fog bank visible NNW-NE, Temperature: 63F, Dew point: 53F, Wind: NE at 11 kts Sea-level pressure: 30.11 inches Hg, falling Visibility: 12 miles, hazy, visibility N-NE 4, SE-SW 35 6-hour maximum temp: 66F BHO SA 1755 100 SCT 250 –OVC 12 197/63/53/0410/011/ FEW CU SE-W FEW CUFRA FOG BNK NNW-NE VSBY N-NE 4 SE-SW 35 HAZY/ 8/271 58028 10066 20056 WEATHER SUMMARY FOR FRIDAY, MAY 15 TEMPERATURE (DEGREES F) MAX.....76 NORMAL.....67 MIN.....54 NORMAL.....47 MEAN....65 NORMAL.....57 DEPARTURE FROM 30-YEAR NORMAL...........+8 TOTAL DEPARTURE FOR THE MONTH..........+42 [+2.6 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............0 DEPARTURE.......-9 TOTAL HEATING UNITS FOR THE MONTH...........117 DEPARTURE......-48 TOTAL HEATING UNITS FOR THE SEASON.........6013 DEPARTURE.....-178 TOTAL HEATING UNITS LAST SEASON TO DATE....5801 DIFFERENCE....+212 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............38 S AT 12:18 A.M. * AEROVANE.............38 S AT 12:44 A.M. ASOS.................N/A DAVIS................39 S AT N/A FASTEST MILE FOR YESTERDAY..............29 S AT 1:05 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE...........29 SSW AT 12:20 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........N/A AVERAGE WIND SPEED AND DIRECTION.......10.8 S ASOS................10.0 DAVIS................9.9 S [187 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE....-0.12 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........2.25 DEPARTURE....+0.40 ASOS..............2.24 TOTAL PRECIPITATION FOR THE YEAR..........16.86 DEPARTURE....-2.94 ASOS.............17.92 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..............78.9 DEPARTURE.....18.8 PRELIMINARY CLIMATE SUMMARY FOR MAY 2009 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 5/1 64/53/59/+7/T/000/00 37 SSW AERO 37 MPH SSW 5/2 68/52/60/+8/0.05/263/31 32 WNW 5/3 64/48/56/+3/T/068/08 25 S 5/4 64/48/56/+3/0.01/009/01 17 SSW 5/5 52/44/48/-5/0.95/000/00 43 NNE AERO 40 MPH NNE 5/6 63/43/53/-1/0.40/189/22 24 SSE 5/7 68/49/59/+5/0.60/009/01 29 S 5/8 75/52/64/+10/0/690/80 28 S 5/9 71/55/63/+8/0.13/104/12 31 W TSTM 5/10 65/46/56/+1/0/840/97 53 W Aero 50 MPH W 5/11 63/41/52/-3/0/781/90 24 WNW 5/12 63/45/54/-2/0/.../.. 22 ENE 5/13 70/45/58/+2/0/.../.. 31 SSE AERO 29 MPH SSE 5/14 62/47/55/-2/0.10/.../.. 53 S AERO 52 MPH S 5/15 76/54/65/+8/0/.../.. 38 S AERO 38 MPH S 5/16 morning low temp: 54F, our normal low temp. 47F NEW DAILY RECORDS FOR MAY 2009... 5/14: RECORD PEAK WIND GUST 53 MPH S; Surpasses previous record of 50 MPH SW in 1976 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 16 HIGH 90F IN 1951 LOW 30F IN 1936 PRECIP 2.63 INCHES IN 1954 PEAK GUST 56e MPH NW IN 1952 RECORDS FOR MAY 17 HIGH 88F IN 1974, 1977 LOW 34F IN 1956, 1957 PRECIP 2.07 INS IN 1916 PEAK GUST 52 MPH SW IN 1967, W IN 1974 TODAY'S REPORT PREPARED BY: Mike Iacono