BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, SEPTEMBER 12, 2015 ALL TIMES ARE IN EASTERN STANDARD TIME MEASURABLE RAINFALL TOTALS 0.91 IN FIRST RAIN EVENT OF MONTH FIRST MEASURABLE RAINFALL SINCE AUGUST 23-24TH LOTS OF MOISTURE LEFT BEHIND AFTER THE RAIN RESULTED IN DENSE FOG EARLY TODAY BLUE HILL OBSERVATORY ASKS FOR YOUR SUPPORT FOR OUR KICKSTARTER FUNDRAISER FOR A NEW AEROVANE ANEMOMETER- PLEASE SUPPORT BY VISITING: https://www.kickstarter.com/projects/1451380431/fund-the-future-of-climate-science-at-blue-hill-ob The first rainfall of September left almost an inch (0.91) by the time it ended at late morning yesterday. It was a very badly needed precipitation event since the last rainfall was way back on August 23-24. Considerable moisture has been left behind the rainstorm and so the formation of low clouds and dense fog, especially here at the summit, dropped our visibility down to 1/16 mile by 8 A.M. EDT observation time this morning. Winds have been light under 10 MPH since noon on Friday. Today's Observations: 7 A.M. Weather: Obscurement dense fog, heavy condensation all surfaces Temperature: 60F; Dew Point: 60F; Wind: SSE at 5 kts, Sea-level pressure: 29.88 ins. Hg, falling, then rising and higher Visibility: 1/16 of a mile, dense fog 6-hr Min temp: 58F 24-hr precip: 0.06 in. BHO SA 1155 W2 X 1/16F 118/60/60/1505/988/ HVY CONDENSATION/ ALL SFCS/ 8//// 51008 ASOS 70007 MANUAL 70006 10062 20058 10 A.M. Weather: Broken stratocumulus Temperature: 68F; Dew Point 63F; Wind: S at 3 kts, estimated, Wind: Light and variable w Sea-level pressure: 29.89 ins. Hg, rising, then falling slightly Visibility: 15 miles, except 20 miles NE-S, hazy BHO SA 1455 E7 BKN 15 123/68/63/E1803/989/ VSBY NE-S 20 HAZY WND L/V/ 8/500 50005 1 P.M. Weather: Scattered cumulus, moderate cumulus except NE, few pathces of altocumulus of chaotic sky, patches dense cirrus Temperature: 72F; Dew Point: 61F; Wind: ENE at 3 kts, estimated Sea-level pressure: 29.86 ins. Hg, falling, then more rapidly Visibility: 60 miles, except 70 miles NW, light distant haze M 6-hr Max: 74F 6-hr Min: 60F 6-hr precip: 0.00 inch BHO SA 1755 26 SCT 150 SCT 220 SCT 250 BKN 60 113/72/61/0703/986/ CU/MDT CU XCPT NE FEW SML PTCHS CHAOTIC AC PTCHS DNS CI ALQDS VSBY NW 70 LGT DSNT HZ WND LGT/ 8/292 58010 10074 20060 SUMMARY FOR FRIDAY, SEPTEMBER 11, 2015 TEMPERATURE (DEGREES F) MAX.....70 NORMAL.....73 MIN.....59 NORMAL.....56 MEAN....68 NORMAL.....65 DEPARTURE FROM 30-YEAR NORMAL.........................0 TOTAL DEPARTURE FOR THE MONTH.......................+73 [+6.4 DEGREES/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY...............0 DEPARTURE..........-2 TOTAL COOLING UNITS FOR THE MONTH..............90 DEPARTURE.........+55 TOTAL COOLING UNITS FOR THE SEASON............756 DEPARTURE........+184 TOTAL COOLING UNITS LAST SEASON TO DATE.......565 DIFFERENCE.......+191 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...................33 NNE AT 5:38 A.M. ASOS........................36 NNE AT 5:38 A.M. DAVIS.......................34 NE AT 5:37 A.M. RMY N/A FASTEST MILE FOR YESTERDAY.................... 23 NE AT 1:21 A.M MAXIMUM 2-MINUTE ASOS AVERAGE..................23 NE AT 1:20 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.................22 NE AT 1:20 A.M. AVERAGE WIND SPEED AND DIRECTION.............. 9.7 NNE ASOS........................9.1 DAVIS.......................8.7 NE [040 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.....0.06 DEPARTURE.....-0.07 ASOS...............0.07 TOTAL PRECIPITATION FOR THE MONTH...........0.91 DEPARTURE.....-0.44 ASOS...............0.91 TOTAL PRECIPITATION FOR THE YEAR...........31.17 DEPARTURE.....-5.20 ASOS................N/A *** *** ASOS annual total not available due to erroneous readings PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY GUST RMY: R.M. Young wind gust recording system TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 9/1 81/65/73/+5/0.00/.../.. 20 SSW RMY 20 9/2 89/64/77/+9/0.00/.../.. 20 SW RMY 21 9/3 85/66/76/+9/T/.../.. 17 E RMY N/A TSTM 9/4 72/58/65/0/0.00/.../.. 31 ENE RMY N/A 9/5 77/55/66/-1/0.00/.../.. 14 SW RMY 18 9/6 87/57/72/+5/0.00/.../.. 21 SSW RMY 22 9/7 92/63/78/+12/0.00/.../.. 23 WSW RMY 24 9/8 97/70/84/+18/0.00/.../.. 22 WSW RMY 24 9/9 92/70/81/+15/0.00/.../.. 30 SSW RMY 33 9/10 73/62/68/+3/..../.../.. 29 NE RMY N/A 9/11 70/59/65/0/..../.../.. 33 NE RMY N/A 9/12 low since midnight is 58F; normal low is now 56F DAILY RECORDS FOR SEPTEMBER 2015 **9/7 DAILY RECORD MAXIMUM TEMPERATURE OF 92F TIES PREVIOUS RECORD SET IN 2007** **9/8 DAILY RECORD MAXIMUM TEMPERATURE OF 97F BREAKS PREVIOUS RECORD OF 93F SET IN 2007** **9/8 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F BREAKS PREVIOUS RECORD OF 69F SET IN 1999** **9/9 DAILY RECORD MAXIMUM TEMPERATURE OF 92F BREAKS PREVIOUS RECORD OF 91F SET IN 2002** **9/9 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F BREAKS PREVIOUS RECORD OF 69F SET IN 1999** DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 12 HIGH 92F IN 1961 LOW 42F IN 1958,1967,1985 PRECIP 2.79 INCHES IN 1960 (HURRICANE DONNA) PEAK GUST 140 MPH SSE IN 1960 (HURRICANE DONNA) RECORDS FOR SEPTEMBER 13 HIGH 91F IN 1957 LOW 40F IN 1985 PRECIP 3.10 INCHES IN 1987 PEAK GUST 44 MPH WNW IN 1986 TODAY'S REPORT PREPARED BY: Robert Skilling