BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, OCTOBER 3, 2015 ALL TIMES ARE IN EASTERN STANDARD TIME COLD AND RAINY THIS MORNING WITH GUSTY NE WINDS... A cold rain continued much of this morning, before ending just before mid-day. A total of 0.15 inches was measured in the six hours ending at 1 PM EST today, and a total of 0.51 has been observed since Thursday evening. Very cool temperatures have continued for the last few days with the onshore flow with a high temperature of only 51F on Friday and 50F so far today. The minimum temperature this morning was 45F around 11 AM EST. The wind has been gusty from the NE with a peak gust during the rain this morning to 36 mph at 10:42 AM EST. This was surpassed with a peak gust to 37 mph NE at 2:47 PM EST. The rain and fog earlier today kept the visibility in the 2-e mile range much of the morning, though drier air to the north began to move in as the rain ended. This increased the visibility to 35-40 miles and better than 75 miles to the NW by early afternoon. September 2015 was the warmest September on record here at Blue Hill Observatory. It also featured the slowest mean wind speed on record for September, the warmest September average maximum temperature and second warmest average minimum temperature. August-September combined was also the warmest on record. September was the fifth sunniest on record with 70 percent of the possible bright sunshine, and August-September combined was the sunniest on record with 72 percent sunshine for those two months. Details below: BHO Warmest Septembers (NWS mean), deg F (1885-2015): 1) 68.2 in 2015 2) 66.9 in 1961 3) 66.5 in 1930 4) 66.4 in 1999 5) 66.2 in 2002 66.2 in 2005 BHO Warmest September Average Maximum Temperature, deg F (1885-2015): 1) 77.8 in 2015 2) 76.6 in 1930 3) 75.7 in 2007 4) 75.6 in 1959 5) 75.5 in 1961 BHO Warmest September Average Minimum Temperature, deg F (1885-2015): 1) 58.8 in 1988 2) 58.5 in 2015 3) 58.2 in 1961 58.2 in 1999 5) 57.8 in 2005 BHO Warmest Aug-Sep (24-hour adjusted mean), deg F (1885-2015): 1) 69.8 in 2015 2) 68.9 in 2005 3) 68.6 in 2002 4) 68.2 in 2010 5) 67.8 in 1959 BHO Slowest September Mean Wind Speed, mph (1885-2015): 1) 10.3 in 2015 2) 10.5 in 2014 3) 10.6 in 2013 4) 10.7 in 2011 5) 10.9 in 1917 10.9 in 2003 BHO Sunniest Septembers, hours (1885-2015): 1) 267.7 in 1983 [74%] 2) 266.9 in 1941 [74%] 3) 265.9 in 2007 [74%] 4) 255.3 in 1948 [71%] 5) 251.9 in 2015 [70%] 6) 251.0 in 1967 [70%] 7) 246.8 in 1952 [69%] 246.8 in 1978 [69%] BHO Sunniest Aug-Sep, hours (1885-2015): 1) 555.1 in 2015 [72%] 2) 553.0 in 1941 [72%] 3) 536.0 in 2007 [69%] 4) 527.3 in 2014 [68%] 5) 520.2 in 1932 [67%] 6) 515.3 in 1921 [67%] 7) 514.3 in 1968 [67%] PRELIMINARY STATS FOR SEPTEMBER 2015 TEMPERATURE, Deg. F Avg. Max. 77.8 [+6.2] Avg. Min. 58.5 [+3.9] Mean 68.2 [+5.1] Corrected mean: 67.3 Max. for month: 97 on 8th Min. for month: 46 on 27th COOLING DEGREE DAYS Total cooling units: 144 [+84] Total for the season: 810 [+213] Total for last season: 587 HEATING DEGREE DAYS Total heating units: 42 [-75] Total for the season: 43 [-99] Total for last season: 101 PRECIPITATION, Inches Total: 3.88 [-0.18] Greatest in 24 hrs: 2.53 inches from 9/29-30 WIND, mph Avg. uncorrected wind speed: 10.1 Avg. corrected wind speed: 10.3 Prevailing wind direction: SSW @ 13% Peak gust and direction: 47 S on the 30th SUNSHINE: Campbell-Stokes card minutes: 15114 mins. of possible 21582 or 70% Astronomical total minutes: 15766 mins. of possible 22472 or 70% Today's Observations: 7 A.M. Weather: Sky partly obscured in light rain and fog, overcast stratocumulus and nimbostratus Temperature: 46F; Dew Point: 46F; Wind: NE at 15G24 kts, Sea-level pressure: 30.40 ins. Hg, pressure rising, then more quickly Visibility: 2 miles 6-hr Max temp: 49F 6-hr Min temp: 46F 24-hr precip: 0.31 inches BHO SA 1155 -X E3 OVC 2R-F 293/46/46/0415G24/040/ F1 PK WND 0426/12/ 8/72/ 53014 60/// 70031 10049 20046 10 A.M. Weather: Light rain and fog, overcast stratocumulus and nimbostratus Temperature: 46F; Dew Point 45F; Wind: NE at 17G27 kts, Peak Wind: 27 knots NE at 9:31 AM EST Sea-level pressure: 30.43 ins. Hg, rising, then more slowly Visibility: 3 miles, variable 2-4 miles 3-hr precip: 0.12 inches BHO SA 1455 E5 OVC 3VR-F 305/46/45/0417G27/043/ VSBY 2V4 PK WND 0427/31/ 8/6// 51012 6012/ 1 P.M. Weather: Overcast stratocumulus Temperature: 47F; Dew Point: 43F; Wind: NE at 17G26 kts Peak Wind: 30 knots NE at 11:58 AM EST Sea-level pressure: 30.42 ins. Hg, decreasing then increasing, now lower Visibility: 40 miles, except 25 miles E-SE, 75 miles WNW-NW 6-hr Max: 47F 6-hr Min: 45F 6-hr precip: 0.15 inches BHO SA 1755 E20 OVC 40 302/47/43/0417G26/042/ VSBY E-SE 25 WNW-NW 75 PK WND 0530/58/ 8/5// 55003 6015/ 10047 20045 SUMMARY FOR FRIDAY, OCTOBER 2, 2015 TEMPERATURE (DEGREES F) MAX.....51 NORMAL.....65 MIN.....47 NORMAL.....48 MEAN....49 NORMAL.....57 DEPARTURE FROM 30-YEAR NORMAL........................-8 TOTAL DEPARTURE FOR THE MONTH.......................-12 [-6.2 DEGREES/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY...............0 DEPARTURE...........0 TOTAL COOLING UNITS FOR THE MONTH...............0 DEPARTURE..........-1 TOTAL COOLING UNITS FOR THE SEASON............810 DEPARTURE........+212 TOTAL COOLING UNITS LAST SEASON TO DATE.......587 DIFFERENCE.......+223 HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY..............16 DEPARTURE..........+7 TOTAL HEATING UNITS FOR THE MONTH..............28 DEPARTURE.........+11 TOTAL HEATING UNITS FOR THE SEASON.............71 DEPARTURE.........-88 TOTAL HEATING UNITS LAST SEASON TO DATE.......124 DIFFERENCE........-53 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...................40 NE AT 7:16 P.M. ASOS........................43 NE AT 7:15 P.M. DAVIS.......................42 NE AT 7:15 P.M. RMY 43 FASTEST MILE FOR YESTERDAY.................... 28 NE AT 9:57 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE..................26 NE AT 11:37 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.................26 NE AT 6:28 P.M. AVERAGE WIND SPEED AND DIRECTION.............18.1 NE ASOS......................16.9 DAVIS.....................15.6 NE [047 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.....0.31 DEPARTURE.....+0.16 ASOS...............0.30 TOTAL PRECIPITATION FOR THE MONTH...........0.37 DEPARTURE.....+0.06 ASOS...............0.35 TOTAL PRECIPITATION FOR THE YEAR...........34.19 DEPARTURE.....-4.88 ASOS................N/A *** *** ASOS annual total not available due to erroneous readings PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER & OCTOBER 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/+5/0.00/766/97 20 SSW RMY 20 9/2 89/64/77/+9/0.00/732/93 20 SW RMY 21 9/3 85/66/76/+9/T/612/78 17 E RMY N/A TSTM 9/4 72/58/65/-2/0.00/297/38 31 ENE RMY N/A 9/5 77/55/66/-1/0.00/748/96 14 SW RMY 18 9/6 87/57/72/+5/0.00/753/97 21 SSW RMY 22 9/7 92/63/78/+12/0.00/727/94 23 WSW RMY 24 9/8 97/70/84/+18/0.00/693/90 22 WSW RMY 24 9/9 92/70/81/+15/0.00/683/89 30 SSW RMY 33 9/10 73/62/68/+3/0.32/000/00 29 NE RMY N/A 9/11 70/59/65/0/0.59/084/11 33 NE RMY N/A 9/12 75/58/67/2/..../380/50 18 SSE RMY 25 9/13 66/60/63/-1/..../000/00 25 E RMY N/A 9/14 70/53/62/-2/0.00/550/73 33 W RMY 35 9/15 82/56/69/+5/0.00/736/98 23 W RMY N/A 9/16 84/62/73/+10/0.00/711/95 17 NW RMY N/A 9/17 87/64/76/+13/0.00/723/97 17 SW RMY 16 9/18 86/64/75/+13/0.00/712/96 21 SSW RMY 21 9/19 80/62/71/+9/0.00/480/65 22 S RMY N/A 9/20 74/55/65/+3/T/552/75 24 S RMY N/A 9/21 65/50/58/-3/0.00/646/88 29 ENE RMY 30 9/22 67/55/61/+0/0.00/183/25 21 E RMY 21 9/23 72/50/61/+1/0.00/677/93 15 E RMY N/A 9/24 72/56/64/+4/0.00/696/96 22 E RMY 21 9/25 66/53/60/0/0.00/556/77 21 E RMY 20 9/26 63/49/56/-3/0.00/633/88 25 ENE RMY 25 9/27 71/46/59/+0/0.00/688/96 17 S RMY 18 9/28 81/57/69/+11/0.00/428/60 22 SSW RMY 24 9/29 82/65/74/+16/..../320/45 28 S RMY N/A 9/30 75/53/64/+6/..../000/00 47 S RMY 51 TSTM 10/1 55/51/53/-4/..../.../.. 39 NE RMY N/A 10/2 51/47/49/-8/..../.../.. 40 NE RMY 43 10/3 low since midnight is 45F; normal low is now 48F DAILY RECORDS FOR SEPTEMBER & OCTOBER 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** **9/17 DAILY RECORD MAXIMUM TEMPERATURE OF 87F BREAKS PREVIOUS RECORD OF 86F SET IN 1915, 1941, AND 1991** **9/18 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 64F TIES PREVIOUS RECORD SET IN 1992** DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR OCTOBER 3 HIGH 82F IN 1922 LOW 28F IN 1899 PRECIP 1.76 INCHES IN 1979 PEAK GUST 62 MPH WNW IN 1964 RECORDS FOR OCTOBER 4 HIGH 84F IN 2007 LOW 28F IN 1888 PRECIP 1.87 INCHES IN 2011 PEAK GUST 59 MPH SSW IN 1990 TODAY'S REPORT PREPARED BY: Mike Iacono