BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, SEPTEMBER 10, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME RAIN SHOWERS PROVIDE 0.03 INCH OF PRECIPITATION; MOISTURE INCREASES DRAMATICALLY OVER PAST 24 HOURS A morning rain shower and one early this afternoon have only provided 0.03 inch of precipitation. No thunder was observed this afternoon. Otherwise, the sky has remained cloudy all day. The more notable weather occurrences over the past 24 hours have been the change in wind direction and the subsequent warmer and much more moist air mass. Late yesterday morning, the wind direction backed from NNW to SSW. As a result, temperatures are a few degrees warmer today compared to yesterday. Most impressive has been the change in the dew point temperature, rising from the lower 40s yesterday morning into the upper 60s this afternoon! It has also been breezy today, with an average wind speed thus far of 18 mph. There have been several gusts in the 25-30 mph range, with a peak gust so far of 30 mph. Today's Observations: 7 A.M. Weather: Light rain shower, scattered stratocumulus, broken stratocumulus, overcast nimbostratus, few stratocumulus lenticularis all quadrants, rain shower SSW-W-NNW moving E, light rain shower began at 6:52 A.M. EST and continued very light Temperature: 62F; Dew Point: 57F; Wind: S at 13 kts. Sea-level pressure: 30.16 ins Hg, rising then falling Visibility: 30 miles, light rain shower, N-E-SSE 50 miles, W-NW 10 miles 24-hr precip: Trace 6-hr precip: Trace 6-hr min. temp: 56F BHO SA 1155 20 SCT E30 BKN 40 OVC 30RW- 212/62/57/1913/016/ FEW SCSL ALQDS VSBY N-E-SSE 50 W-NW 10 SHRA SSW-W-NNW MOVG E RW-B52 CTD VRY LGT/ 8/52/ 50000 MANUAL 7000/ 6000/ 10062 20056 10 A.M. Weather: Broken stratocumulus, overcast stratus, hazy Temperature: 66F; Dew Point: 61F; Wind SSW at 15G22 kts, Wind: Direction variable S-WSW Sea-level pressure: 30.15 ins. Hg, falling slightly Visibility: 35 miles, hazy 3-hr precip: 0.01 inch BHO SA 1455 E10 BKN 15 OVC 35 209/66/61/2115G22/015/ HAZY WND 18V24/ 8/5// 55003 MANUAL 60001 ASOS 60001 1 P.M. Weather: Broken stratocumulus, overcast stratus, thin overcast NE, sun dimly visible, hazy, rain shower WNW-N moving ESE, light rain became very light and intermittent at 12:25 P.M. EST and ended at 12:46 P.M. EST and was mostly very light Temperature: 69F; Dew Point: 66F; Wind SSW at 15G22 kts, Wind: Direction variable S-WSW Sea-level pressure: 30.07 ins. Hg, falling Visibility: 15 miles, hazy, SE-SW 20 miles, W-NE 15 miles 6-hr precip: 0.03 inch 6-hr max. temp: 69F BHO SA 1755 E10 BKN 15 OVC 15 183/69/66/2115G22/007/ THN OVC NE SUN DIMLY VSBL HAZY SHRA WNW-N MOVG ESE VSBY W-NE 15 SE-SW 20 WND 18V24 R- BCMG VRY LGT AND INTMT 25 E46 MSTLY VRY LGT/ 8/5// 56026 MANUAL 60003 ASOS 60004 10069 20060 WEATHER SUMMARY FOR MONDAY, SEPTEMBER 9, 2013 TEMPERATURE (DEGREES F) MAX.....69 NORMAL.....74 MIN.....47 NORMAL.....57 MEAN....58 NORMAL.....66 DEPARTURE FROM 30-YEAR NORMAL.......................-8 TOTAL DEPARTURE FOR THE MONTH......................-18 [-2.2 DEGREES/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY..............0 DEPARTURE.........-3 TOTAL COOLING UNITS FOR THE MONTH.............23 DEPARTURE.........-7 TOTAL COOLING UNITS FOR THE SEASON...........663 DEPARTURE........+96 TOTAL COOLING UNITS LAST SEASON TO DATE......754 DIFFERENCE.......-91 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..................23 SW AT 9:21 P.M. AERO.......................23 SSW AT 11:49 P.M. ASOS.......................25 SW AT 9:21 P.M. DAVIS......................24 S AT 10:43 P.M. RMY N/A FASTEST MILE FOR YESTERDAY....................19 SSW AT 10:48 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE.................18 SSW AT 11:58 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE................18 SSW AT 10:51 P.M. AVERAGE WIND SPEED AND DIRECTION............10.5 SSW ASOS.....................10.2 DAVIS.....................9.2 SW [233 degrees] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...Trace DEPARTURE.............-0.13 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........2.83 DEPARTURE.............+1.73 ASOS..............2.95 TOTAL PRECIPITATION FOR THE YEAR..........40.84 DEPARTURE.............+4.72 ASOS..............N/A* *ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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 9/1 76/67/72/+4/2.32/008/01 33 S AERO 39 MPH S RMY 38 TSTM 9/2 79/67/73/+5/0.43/056/07 30 SSE AERO 33 MPH SSE RMY N/A TSTM 9/3 79/61/70/+3/0.00/219/28 28 S AERO 29 MPH S RMY 30 TSTM 9/4 78/57/68/+1/0.00/733/94 24 W AERO 25 MPH W RMY 25 9/5 66/51/59/-8/0.08/179/23 20 NNE AERO 20 MPH NNE RMY 21 9/6 68/46/57/-10/0.00/751/97 18 WSW AERO 17 MPH WSW RMY N/A 9/7 78/51/65/-1/0.00/594/77 20 WSW AERO 21 MPH WSW RMY 21 9/8 74/50/62/-4/0.00/646/84 31 NW AERO 33 MPH NW RMY 32 9/9 69/47/58/-8/T/.../.. 23 SW AERO 23 MPH SSW RMY N/A 9/10 morning low temp: 56F; the normal low is now 57F DAILY RECORDS FOR SEPTEMBER 2013 9/1 - NEW DAILY RECORD MAXIMUM PRECIPITATION OF 2.32 INCHES; surpasses previous record of 1.60 inches set in 1927 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 10 HIGH 90F IN 1931,1989 LOW 41F IN 1956 PRECIP 5.60 INCHES IN 1999 (DAILY RECORD FOR SEPTEMBER) PEAK GUST 48 MPH NW IN 1972 RECORDS FOR SEPTEMBER 11 HIGH 93F IN 1983 LOW 37F IN 1917 PRECIP 5.23 INCHES IN 1954 (HURRICANE EDNA) PEAK GUST 101 MPH NW IN 1954 (HURRICANE EDNA) TODAY'S REPORT PREPARED BY: Sean Fankhauser