BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, AUGUST 24, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME ANOTHER BEAUTIFUL SUMMER DAY It has been another beautiful summer day today. The temperature fell to 55F this morning, the coolest reading in over a week. It has rebounded into the low 70s this afternoon, which is below normal for today's date. In addition to these comfortable temperatures, the dew point has been very low today, falling from around 50F this morning to just under 40F by early afternoon, making the air feel very refreshing. Dew points this low have not been observed since late May! The sky has been mostly sunny all day, with only a few fair weather clouds. Winds have been steady at about 10mph out of the N-E today, with a few gusts over 20mph. Visibility has been good today, averaging about 75 miles. Also of note today is the high barometric pressure, as the sea level pressure this afternoon has risen to 30.33 ins. Hg, the highest reading of this month so far. The dry stretch of weather continues, with no measurable precipitation recorded on the summit since 0.02 inches of rain fell August 13. This is the longest such streak since we went 12 days without measurable precipitation from April 26 through May 7 of this year. With no rain expected today or tomorrow, we are likely to tie that streak. Despite the recent dry weather, the month is currently only a little over half an inch below normal, largely due to the 2.21 inches of rain on August 9. That one rain event accounts for about 87% of the monthly precipitation so far. Today's Observations: 7 A.M. Weather: Clear, few altocumulus castellanus NE-SE, few cirrus NE-SE Temperature: 61F; Dew Point: 50F; Wind: NE at 9 kts Sea-level pressure: 30.29 ins. Hg, rising then rising more slowly Visibility: 75 miles, light distant haze 6-hr min. temp: 55F BHO SA 1155 CLR 75 256/61/50/0409/029/ FEW ACC NE-SE FEW CI NE-SE LGT DSNT HZ/ 8/081 51024 10062 20055 10 A.M. Weather: Clear, few small cumulus and cumulus fractus distant SE-SSE, few altocumulus castellanus distant E-SE, few cirrus distant NE-SE Temperature: 70F; Dew Point: 45F; Wind: ENE at 10G18 kts, Wind: Direction variable NNE-E Sea-level pressure: 30.32 ins. Hg, rising then rising more slowly Visibility: 75 miles, light distant haze BHO SA 1455 CLR 75 269/70/45/0610G18/032/ FEW SML CU AND CUFRA DSNT SE-SSE FEW ACC DSNT E-SE FEW CI DSNT NE-SE LGT DSNT HZ WND 03V10/ 8/181 51013 1 P.M. Weather: Clear, few cirrus and dense cirrus SW-NNW, dense cirrus distant offshore ENE-E Temperature: 70F; Dew Point: 39F; Wind: E at 10 kts, Wind: Direction variable NE-ESE Sea-level pressure: 30.33 ins. Hg, rising slightly Visibility: 75 miles, light distant haze 6-hr max. temp: 72F BHO SA 1755 CLR 75 271/70/39/0910/033/ FEW CI AND DNS CI SW-NNW DNS CI DSNT OFFSHR ENE-E LGT DSNT HZ WND 05V12/ 8/001 53002 10072 20061 WEATHER SUMMARY FOR FRIDAY, AUGUST 23, 2013 TEMPERATURE (DEGREES F) MAX.....78 NORMAL.....79 MIN.....63 NORMAL.....61 MEAN....70 NORMAL.....70 DEPARTURE FROM 30-YEAR NORMAL........................0 TOTAL DEPARTURE FOR THE MONTH......................-28 [-1.4 DEGREES/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY..............5 DEPARTURE..........0 TOTAL COOLING UNITS FOR THE MONTH............116 DEPARTURE........-33 TOTAL COOLING UNITS FOR THE SEASON...........599 DEPARTURE........+99 TOTAL COOLING UNITS LAST SEASON TO DATE......660 DIFFERENCE.......-61 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY................25 NNW AT 7:37 A.M. AERO.....................25 NNW AT 7:37 A.M. * ASOS.....................26 NNW AT 7:38 A.M. DAVIS....................22 NNW AT 7:37 A.M. RMY: 24 FASTEST MILE FOR YESTERDAY..................18 NNW AT 4:05 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE...............17 NW AT 4:05 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..............15 NW AT 4:04 A.M. AVERAGE WIND SPEED AND DIRECTION...........9.1 NNW ASOS....................8.8 DAVIS...................7.9 NNW [345 deg.] * last of several 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..........2.55 DEPARTURE............-0.58 ASOS..............2.60 TOTAL PRECIPITATION FOR THE YEAR..........37.84 DEPARTURE............+3.72 ASOS..............N/A* *ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals PRELIMINARY CLIMATE SUMMARY FOR AUGUST 2013 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust RMY: RMY = R.M. Young wind gust recording system added 8/9/2011 TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 8/1 81/62/72/0/0.01/503/58 25 S AERO 26 MPH S RMY 27 8/2 81/62/72/0/0.23/518/60 26 W AERO 26 MPH W RMY 28 8/3 77/63/70/-2/T/276/32 22 WSW AERO 23 MPH WSW RMY 23 8/4 79/58/69/-3/T/645/75 25 WNW AERO 21 MPH WNW RMY 26 8/5 75/54/65/-7/0.00/858/100 26 WNW AERO 25 MPH WNW RMY 27 8/6 78/56/67/-5/0.00/846/99 17 ESE AERO 15 MPH S RMY 16 8/7 80/59/70/-2/0.00/759/89 21 S AERO 21 MPH S RMY N/A 8/8 79/62/71/-1/0.08/153/18 25 S AERO 25 MPH S RMY N/A 8/9 73/70/72/0/2.21/000/00 37 S AERO 39 MPH S RMY 40 8/10 81/61/71/-1/0.00/795/94 30 WNW AERO 31 MPH WNW RMY 31 8/11 78/58/68/-3/0.00/835/99 18 W AERO 18 MPH W RMY 21 8/12 81/62/72/+1/0.00/656/78 18 W AERO 17 MPH WSW RMY 19 8/13 73/64/69/-2/0.02/193/23 16 SSE AERO 15 MPH SSE RMY N/A 8/14 73/57/65/-6/0.00/819/98 35 W AERO 35 MPH W RMY 35 8/15 75/53/64/-7/0.00/800/96 23 W AERO 23 MPH W RMY 24 8/16 77/57/67/-4/0.00/740/89 20 W AERO 19 MPH W RMY 21 8/17 77/59/68/-3/0.00/770/93 18 W AERO 18 MPH W RMY N/A 8/18 80/62/71/0/T/231/28 16 SSW AERO 17 MPH SSW RMY 18 8/19 82/58/70/0/T/494/60 17 W AERO 18 MPH W RMY 20 8/20 85/64/75/+5/0.00/772/94 17 NW AERO 18 MPH NW RMY N/A 8/21 87/65/76/+6/0.00/802/98 18 WSW AERO 18 MPH WSW RMY 18 8/22 84/67/76/+6/0.00/.../.. 22 SW AERO 22 MPH SSW RMY N/A 8/23 78/63/70/0/0.00/.../.. 25 NNW AERO 25 MPH NNW RMY 24 8/24 morning low temp: 55F; the normal low is now 61F DAILY RECORDS FOR AUGUST 2013 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR AUGUST 24 HIGH 92F IN 1947 LOW 43F IN 1971 PRECIP 2.40 INCHES IN 2010 PEAK GUST 54 MPH W IN 1986 RECORDS FOR AUGUST 25 HIGH 93F IN 1947, 1948, 2007 LOW 41F IN 1940 PRECIP 2.69 INCHES IN 2010 PEAK GUST 60e MPH SSW IN 1941 TODAY'S REPORT PREPARED BY: Jonathan O'Brien