BLUE HILL OBSERVATORY MILTON, MA MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, SEPTEMBER 27, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME BLUE HILL SUMMIT IN THE LOW CLOUDS TODAY LIGHT RAIN AND RAIN SHOWERS AND DRIZZLE COMBINE TO MAKE FOR A COOL AND DAMP DAY The summit has been enveloped in low stratus clouds today with visibility down to 1/16 variable to 1/8 mile. Light rain and showers began in the very early morning hours producing just 0.16 inch through 8 AM EDT. Some additional precipitation was in the form of light drizzle bringing another 0.02 by 2 PM. Today's observations: 7 A.M. Weather: Obscurement with heavy fog, light rain occurring Temperature: 57F, Dew point: 57F; Wind: NE at 12G20 kts Sea-level pressure: 30.17 inches Hg, falling Visibility: 1/8 variable to 1/16 mile 6-hour minimum temp: 56F 6-hourly rainfall: 0.16 inch 24-hour rainfall: 0.16 inch BHO SA 1155 W2 X 1/8R-F 218/57/57/0512G20/017/ VSBY 1/8V1/16/ 8//// 58000 ASOS 60015 MANUAL 6016/ ASOS 70015 MANUAL 70016 10057 20056 10 A.M. Weather: Obscurement ceiling variable 2 hundred to 3 hundred, light drizzle occurring Temperature: 58F, Dew point: 58F; Wind: NNE at 10 kts, Wind: Direction variable N to ENE, Wind: Gust to 19 kts past hour Sea-level pressure: 30.17 inches Hg, falling Visibility: 1/8 mile 3-hourly rainfall: 0.02 inch BHO SA 1455 WV3 X 1/8L-F 217/58/58/0310/017/ CIG 2V3 GST TO 19 KTS PST HR WND 35V06/ 8//// 58001 ASOS 60002 MANUAL 6002/ 1 P.M. Weather: Obscurement with heavy fog, very light drizzle occurring... Temperature: 59F, Dew point: 59F; Wind: NNE at 11 kts Wind: Direction variable NNW to NE Sea-level pressure: 30.13 inches Hg, falling Visibility: 1/16 mile 6-hour maximum temp: 59F 6-hour rainfall: 0.02 in. BHO SA 1755 W2 X 1/16L-F 202/59/59/0211/013/ PCPN VRY LGT WND 34V05/ 8//// 58015 ASOS 60002 MANUAL 6002/ 10059 20057 WEATHER SUMMARY FOR SUNDAY, SEPTEMBER 26 TEMPERATURE (DEGREES F) MAX.....68 NORMAL.....68 MIN.....56 NORMAL.....50 MEAN....62 NORMAL.....59 DEPARTURE FROM 30-YEAR NORMAL..............+3 TOTAL DEPARTURE FOR THE MONTH.............+86 [+3.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............3 DEPARTURE........-4 TOTAL HEATING UNITS FOR THE MONTH........... 60 DEPARTURE.......-47 TOTAL HEATING UNITS FOR THE SEASON...........73 DEPARTURE.......-65 TOTAL HEATING UNITS LAST SEASON TO DATE.....130 DIFFERENCE......-57 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............25 NE AT 5:13 P.M. AEROVANE..............28 NE AT 5:13 P.M. ASOS..................26 NE AT 5:14 P.M. DAVIS.................25 NE AT 10:04 A.M. THE FASTEST MILE FOR YESTERDAY.......... 17 NE AT 5:18 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............18 NE AT 5:19 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........19 NE AT 10:06 A.M. AVERAGE WIND SPEED AND DIRECTION.......11.1 NE ASOS................10.5 DAVIS...............10.5 NNE [030 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.16 DEPARTURE........+0.02 ASOS..............0.15 TOTAL PRECIPITATION FOR THE MONTH..........1.24 DEPARTURE........-2.33 ASOS..............1.20 TOTAL PRECIPITATION FOR THE YEAR..........47.27 DEPARTURE.......+10.23 ASOS.............47.04 ** ** ASOS missing rainfall due to system failure on 6/24-25 PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 2010 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust when significant TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 9/1 93/73/83/+16/0.00/765/97 18 SW 9/2 93/72/83/+17/0.00/740/94 25 SSW 9/3 83/69/76/+10/0.47/039/05 25 NNE 9/4 79/62/71/+5/0.00/672/86 37 WSW AERO 39 MPH WSW 9/5 73/55/64/-1/0.00/778/100 28 SW AERO 32 MPH SW 9/6 76/54/65/0/T/768/99 22 SSW 9/7 84/62/73/+8/0.00/440/57 30 SSW AERO 32 MPH S 9/8 80/59/70/+5/0.08/300/39 35 W AERO 40 MPH W TSTM 9/9 72/55/64/0/T/352/46 28 W 9/10 67/55/61/-3/0.00/260/34 26 WNW 9/11 68/53/61/-3/0.00/723/95 18 NE 9/12 63/54/59/-4/T/045/06 22 ENE AERO 24 MPH NE 9/13 67/54/61/-2/0.02/091/12 22 S 9/14 74/53/64/+1/T/489/65 31 WSW AERO 32 MPH WSW 9/15 67/49/58/-4/0.00/660/88 28 W AERO 31 MPH W 9/16 70/46/58/-4/0.26/530/71 43 S 9/17 68/53/61/-1/0.25/000/00 45 S 9/18 65/53/59/-2/0.00/193/26 15 SE 9/19 76/54/65/+4/T/451/61 17 SW AERO 22 MPH SW 9/20 69/50/60/-1/0.00/707/96 29 NW AERO 33 MPH NW 9/21 70/46/58/-2/0.00/711/97 31 S AERO 35 MPH S 9/22 84/58/71/+11/T/.../.. 32 SSW AERO 36 MPH SSW 9/23 73/58/66/+6/0.00/.../.. 20 SSE 9/24 81/58/70/+11/T/.../.. 29 S 9/25 86/63/75/+16/0.00/.../.. 28 WSW 9/26 68/56/62/+3/..T/.../.. 25 NE AERO 28 MPH NE 9/27 our overnight low temp: 56F; the normal low is now 49F NEW DAILY RECORDS FOR SEPTEMBER 2010 9/1 - High maximum temperature of 93F equals the previous record of 93F set in 1969 9/1 - High minimum temperature of 73F surpasses the previous record of 71F in 1898, 1959 9/2 - High minimum temperature of 72F surpasses the previous record of 71F in 1959 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 27 HIGH 84F IN 1998 LOW 32F IN 1947 PRECIP 2.26 INCHES IN 1962 PEAK GUST 100 MPH SSE IN 1985 (HURRICANE GLORIA) RECORDS FOR SEPTEMBER 28 HIGH 82F IN 1959 LOW 33F IN 1897,1947 PRECIP 2.46 INCHES IN 2004 PEAK GUST 69 MPH NE IN 1962 TODAY'S REPORT PREPARED BY: Robert Skilling