BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, AUGUST 18, 2017 ALL TIMES ARE IN EASTERN STANDARD TIME OVERCAST AND MODERATELY WINDY DAY The skies remained overcast with stratus clouds all day. Winds coming from the south-southeast began to pick up early this morning, and we have had a peak gust of 33 MPH by the 1:00 PM observation. Pressure has been falling throughout the day with the anticipation of evening rainstorms. Humidity remained high all day leaving sticky air on top of Great Blue Hill. Looking back at the historical records, back in 1955 on this date 5.75 inches of rain fell due to Tropical Storm Diane, which was followed by another 7.02 inches the next day. The total of 12.77 inches remains the highest two-day rainfall amount on record at Blue Hill. Today's Observations: 7 A.M. Weather: Overcast stratus Temperature: 68F; Dew Point: 63F; Wind: SSE at 12G18 kts Sea-level pressure: 29.98 ins. Hg, rising, then falling Visibility: 30 miles 6-hr Max temp: 67F 6-hr Min temp: 64F 24-hr precip: 0.00 in. BHO SA 1155 E60 OVC 30 151/68/63/1612G18/998/ DSNT FG ALQDS/ 8/6// 50001 10067 20064 10 A.M. Weather: Overcast stratus Temperature: 75F; Dew Point: 68F; Wind: SSE at 13G21 kts Sea-level pressure: 29.93 ins. Hg, falling, then more quickly Visibility: 15 miles BHO SA 1455 E110 OVC 15 136/75/68/1613G21/993/ DSNT FG ALQDS/ 8/6// 56015 1 P.M. Weather: Overcast stratus fractus Temperature: 76F; Dew Point: 69F; Wind: S at 16G27 kts, Sea-level pressure: 29.90 ins. Hg, falling, then more quickly Visibility: 30 miles 6-hr Max temp: 79F 6-hr Min temp: 71F BHO SA 1755 E90 OVC 30 124/76/69/1916G27/990/ DSNT FG ALQDS PK WND 1927/57/ 8/7// 58012 10079 20071 SUMMARY FOR THURSDAY, AUGUST 17, 2017 TEMPERATURE (DEGREES F) MAX.....81 NORMAL.....79 MIN.....58 NORMAL.....62 MEAN....70 NORMAL.....71 DEPARTURE FROM 30-YEAR NORMAL.........................-1 TOTAL DEPARTURE FOR THE MONTH.........................+9 [+0.3 DEGREES/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY...............5 DEPARTURE..........-1 TOTAL COOLING UNITS FOR THE MONTH.............114 DEPARTURE..........+4 TOTAL COOLING UNITS FOR THE SEASON............540 DEPARTURE.........+74 TOTAL COOLING UNITS LAST SEASON TO DATE.......658 DEPARTURE........-118 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...................15 SSW AT 2:00 A.M. AERO........................14 SSW AT 1:28 A.M. ASOS........................18 N AT 2:01 A.M. DAVIS.......................15 NW AT 1:27 A.M. RMY N/A FASTEST MILE FOR YESTERDAY.....................12 SSW AT 1:50 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE..................11 N AT 1:56 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.................13 N AT 1:54 A.M. AVERAGE WIND SPEED AND DIRECTION..............7.4 NNW ASOS.......................7.7 DAVIS......................6.2 W [279 DEG.] *last of multiple occurrences PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE......-0.13 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.39 DEPARTURE......-0.97 ASOS..............1.38 TOTAL PRECIPITATION FOR THE YEAR..........36.15 DEPARTURE......+2.80 ASOS...............N/A *** *** ASOS annual total not available due to erroneous readings PRELIMINARY CLIMATE SUMMARY FOR AUGUST CALENDAR DAY DATA DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST AERO: Aerovane wind recording system 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 M: Missing data 8/1 87/65/76/+4/0.00/762/88 16 ESE*AERO 16 NNW RMY 16 8/2 86/65/76/+4/1.09/372/43 32 W AERO 36 W RMY 34 TSTM 8/3 83/65/74/+2/0.00/552/64 22 S AERO 23 S RMY 24 8/4 84/66/75/+3/0.00/697/81 26 S AERO 30 S RMY 29 8/5 75/63/69/-3/0.10/060/07 23 NW AERO 28 NW RMY 29 8/6 76/57/67/-5/0.00/795/93 30 NW AERO 32 NW RMY 31 8/7 76/60/68/-4/0.01/597/70 28 SSW AERO 28 SSW RMY 29 8/8 74/60/67/-5/0.02/000/00 17 S AERO 16 SSE RMY 16 8/9 83/58/71/-1/0.00/.../.. 18 S AERO 18 S RMY 19 8/10 86/63/75/+4/T/.../.. 20 S AERO 18 S RMY 20 8/11 82/63/73/+2/0.00/.../.. 17 S AERO 16 S RMY 17 8/12 75/57/66/-5/0.17/.../.. 22 SSW*AERO 22 SSW RMY 23 8/13 84/67/76/+5/0.00/.../.. 26 WNW AERO 24 WNW RMY 26 8/14 82/67/75/+4/0.00/.../.. 14 SSW*AERO 14 S RMY 15 8/15 79/64/72/+1/T/.../.. 21 S AERO 21 S RMY 23 8/16 83/64/74/+3/0.00/.../.. 23 NW* AERO 23 NW RMY 25 8/17 81/58/70/-1/0.00/.../.. 15 SSW AERO 14 SSW RMY N/A 8/18 Low temp since midnight is 63F; normal low is now 62F DAILY RECORDS FOR AUGUST None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR AUGUST 18 HIGH 93F IN 2002 LOW 47F IN 1824 PRECIP 5.75 INCHES IN 1955 [DIANE] PEAK GUST 46 MPH WNW IN 2007 RECORDS FOR AUGUST 19 HIGH 90F IN 1906, 1966, 2002 LOW 48F IN 1958 PRECIP 7.02 INCHES IN 1955 [DIANE - RECORD FOR MONTH] PEAK GUST 78 MPH ENE IN 1991 – HURRICANE BOB TODAY'S REPORT PREPARED BY: Kaitlin Geagan