BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 30, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Today's observations: 7 A.M. Weather: Scattered stratus, broken stratocumulus, broken altocumulus, overcast cirrus, few thin spots in overcast, stratus fractus drifting below summit Temperature: 60F, Dew point: 60F, Wind: WNW at 6 kts, Sea-level pressure: 29.68 inches Hg, rising Visibility: 20 mile2 6-hour minimum temp: 59F 6-hour precipitation: 0.16 in. 24-hour precipitation: 0.21 in. BHO SA 1155 5 SCT E30 BKN 85 BKN 200 OVC 20 051/60/60/2906/968/ FEW THN SPTS IOVC STFRA DRFTG BLO SMT WND LGT/ 8/571 53010 6016/ 70021 10061 20059 10 A.M. Weather: Scattered cumulus, few cirrus and altocumulus Temperature: 68F, Dew point: 58F, Wind: W at 10 kts, Wind: Direction variable WSW-WNW Sea-level pressure: 29.68 inches Hg, steady Visibility: 60 miles, visibility 70 miles NW BHO SA 1455 35 SCT 60 051/68/58/2710/968/ FEW CI AND AC DSNT NE-SE VSBY NW 70 WND 24V30/ 8/571 56000 1 P.M. Weather: Scattered variable broken cumulus and cumulus congestus, scattered cirrus, hazy Temperature: 74F, Dew point: 53F, Wind: W at 13G18 kts Wind: Direction variable WSW to NW Sea-level pressure: 29.65 inches Hg, falling Visibility: 50 miles, hazy 6-hour maximum temp: 75F BHO SA 1755 E45 BKN 250 BKN 50 042/74/53/2813G18/965/ SCT V BKN FEW MDT CU HAZY WND 25V31/ 8/201 58009 10075 20060 WEATHER SUMMARY FOR FRIDAY, MAY 29 TEMPERATURE (DEGREES F) MAX.....63 NORMAL.....71 MIN.....48 NORMAL.....51 MEAN....56 NORMAL.....61 DEPARTURE FROM 30-YEAR NORMAL...........-5 TOTAL DEPARTURE FOR THE MONTH..........+37 [+1.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............9 DEPARTURE.......+4 TOTAL HEATING UNITS FOR THE MONTH...........222 DEPARTURE......-39 TOTAL HEATING UNITS FOR THE SEASON.........6118 DEPARTURE.....-169 TOTAL HEATING UNITS LAST SEASON TO DATE....5898 DIFFERENCE....+220 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............17 NE AT 7:05 A.M. * AEROVANE..............14 NE AT 7:04 A.M. * ASOS..................15 E AT 7:04 A.M. DAVIS.................15 NE AT N/A FASTEST MILE FOR YESTERDAY...............12 NE AT 7:04 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE............13 E AT 7:05 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........13 NE AT 7:03 A.M. AVERAGE WIND SPEED AND DIRECTION.........5.4 NE ASOS..................4.3 DAVIS.................4.5 ENE [059 DEG] * Last of several occurrences. PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.21 DEPARTURE....+0.09 ASOS..............0.21 TOTAL PRECIPITATION FOR THE MONTH..........3.86 DEPARTURE....+0.33 ASOS..............3.85 TOTAL PRECIPITATION FOR THE YEAR..........18.47 DEPARTURE....-3.01 ASOS.............19.53 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/+8/0.14/104/12 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/-2/0/696/80 22 ENE 5/13 70/45/58/+2/0/732/84 31 SSE AERO 29 MPH SSE 5/14 62/47/55/-2/0.10/166/19 53 S AERO 52 MPH S 5/15 76/54/65/+8/0/474/54 38 S AERO 38 MPH S 5/16 68/54/61/+4/T/457/52 35 S AERO 35 MPH S 5/17 61/49/55/-2/0.09/009/01 35 WNW AERO 33 MPH WNW 5/18 53/42/48/-10/0.04/168/19 27 NE 5/19 70/42/56/-2/0/813/92 28 S 5/20 82/49/66/+8/0/771/87 31 SSW 5/21 89/59/74/+15/0/870/98 37 S AERO 34 MPH S 5/22 87/59/73/+14/0/739/83 31 N 5/23 65/50/58/-1/T/428/48 28 NE 5/24 80/50/65/+5/1.07/536/60 25 WNW TSTM TRACE DIME SIZE HAIL 5/25 76/51/64/+4/0/868/97 32 N 5/26 58/46/52/-8/0/601/67 28 NNE 5/27 52/43/48/-13/0.16/000/00 23 E AERO 19 MPH E 5/28 48/45/47/-14/0.03/000/00 28 NE AERO 25 MPH NNE 5/29 63/48/56/-5/..../000/00 17 NE 5/30 our morning low temp: 59F; the normal low is now 51F 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 30 HIGH 93F IN 1929 LOW 39F IN 1949,1961 PRECIP 1.47 INS 1948 PEAK GUST 61e MPH NW IN 1945 RECORDS FOR MAY 31 HIGH 92F IN 1944,1987 LOW 35F IN 1961 PRECIP 5.02 INS 1984 (RECORD FOR MAY) PEAK GUST 54e MPH WNW IN 1945 TODAY'S REPORT PREPARED BY: Mike Iacono