BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SUNDAY, SEPTEMBER 22, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME MORNING RAINFALL TOTALS UNDER HALF AN INCH CLEARING AND SEASONABLE THIS AFTERNOON Rainfall last night and into this morning left a total of 0.39 inches of rain. The steady rain ended between 7:00 AM and 8:00 AM this morning, and another brief, light rain shower occurred around 9:45 AM. This rain has once again pushed our rainfall surplus for September above one inch, though that surplus will likely decrease this week. This morning's rain was associated with a cold front passing through the region, which will allow for cooler, drier air to settle into New England for the next few days. Winds were gusty out of the south ahead of the front, with several gusts of 35mph yesterday afternoon and a 38mph gust during the heaviest rain this morning. The temperature has climbed slowly today, reaching 69F so far after a warm morning low of 60F. The sky cleared quickly from late morning into early afternoon, with plenty of sunshine developing along with some stratocumulus clouds. The wind has been much lighter today than yesterday, with no gusts greater than 21mph since 7AM, and it has been coming in mostly from the W and WNW, which typically brings in drier air. Visibility has also improved significantly since this morning, rising from 15 miles to about 70 miles this afternoon. Today's Observations: 7 A.M. Weather: Light rain, scattered stratus fractus, overcast nimbostratus, few stratus fractus drifting below summit Temperature: 60F; Dew Point: 60F; Wind: WNW at 10 kts Sea-level pressure: 29.69 ins. Hg, rising Visibility: 15 miles 6-hr min. temp: 60F 24-hr precip: 0.38 inches 6-hr precip: 0.38 inches BHO SA 1155 10 SCT E25 OVC 15R- 054/60/60/2910/969/ FEW STFRA DRFTNG BLO SMT/ 8/72/ 52017 MANUAL 70038 ASOS 70039 MANUAL 60038 ASOS 60039 10068 20060 10 A.M. Weather: Broken stratus fractus, overcast altostratus, few stratus fractus drifting below summit, cumulus distant SE, light rain shower began 9:40 EST, ended 9:50 EST Temperature: 61F; Dew Point: 60F; Wind: WNW at 7 kts Sea-level pressure: 29.70 ins. Hg, rising slightly Visibility: 30 miles 3-hr precip: 0.01 inch BHO SA 1455 E15 BKN 100 OVC 30 059/61/60/2907/970/ FEW STFRA DRFTNG BLO SMT CU DSNT SE R-B40E50/ 8/770 52005 MANUAL 60001 ASOS 60002 1 P.M. Weather: Scattered stratocumulus, altostratus distant NNE-S Temperature: 69F; Dew Point: 56F; Wind: WNW at 9 kts, Wind: Direction variable WSW-NW Sea-level pressure: 29.68 ins. Hg, rising slightly then falling Visibility: 70 miles, light distant haze 6-hr max. temp: 69F 6-hr precip: 0.01 inch BHO SA 1755 30 SCT 70 052/69/56/2909/968/ AS DSNT NNE-S LGT DSNT HZ WND 25V32/ 8/570 58007 MANUAL 60001 ASOS 60002 10069 20060 WEATHER SUMMARY FOR SATURDAY, SEPTEMBER 21, 2013 TEMPERATURE (DEGREES F) MAX.....74 NORMAL.....70 MIN.....57 NORMAL.....53 MEAN....66 NORMAL.....61 DEPARTURE FROM 30-YEAR NORMAL......................+5 TOTAL DEPARTURE FOR THE MONTH.....................-5 [-0.1 DEGREE/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY..............1 DEPARTURE..........0 TOTAL COOLING UNITS FOR THE MONTH.............56 DEPARTURE.........+4 TOTAL COOLING UNITS FOR THE SEASON...........696 DEPARTURE.......+107 TOTAL COOLING UNITS LAST SEASON TO DATE......765 DIFFERENCE.......-69 HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY..............0 DEPARTURE.........-5 TOTAL HEATING UNITS FOR THE MONTH.............64 DEPARTURE.........+7 TOTAL HEATING UNITS FOR THE SEASON............76 DEPARTURE.........-6 TOTAL HEATING UNITS LAST SEASON TO DATE.......42 DIFFERENCE.......+34 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..................35 S AT 4:50 P.M. * AERO.......................40 S AT 3:44 P.M. ASOS.......................39 S AT 3:04 P.M. DAVIS......................36 S AT 3:23 P.M. RMY N/A FASTEST MILE FOR YESTERDAY....................30 S AT 4:13 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE.................28 S AT 4:14 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE................27 S AT 4:14 P.M. AVERAGE WIND SPEED AND DIRECTION.............16.0 S ASOS......................15.2 DAVIS.....................14.5 S [188 degrees] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.38 DEPARTURE.............+0.23 ASOS..............0.39 TOTAL PRECIPITATION FOR THE MONTH..........3.90 DEPARTURE.............+1.16 ASOS..............4.02 TOTAL PRECIPITATION FOR THE YEAR..........41.91 DEPARTURE.............+4.15 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/529/69 23 SW AERO 23 MPH SSW RMY N/A 9/10 73/56/65/0/0.03/007/01 30 S AERO 32 MPH S RMY 33 9/11 93/68/81/+16/0.00/654/86 25 SW AERO 27 MPH SW RMY N/A 9/12 85/66/76/+11/0.47/455/60 32 S AERO 33 MPH S RMY 34 TSTM 9/13 79/58/69/+5/0.17/242/32 24 NNW AERO 25 MPH NNW RMY 23 9/14 67/52/60/-4/0.00/361/48 21 NW AERO 21 MPH NW RMY 21 9/15 70/48/59/-5/0.00/547/73 17 WSW AERO 18 MPH WSW RMY 20 9/16 66/46/56/-7/0.02/179/24 29 NNW AERO 31 MPH NNW RMY 30 9/17 60/40/50/-13/0.00/722/97 27 NNE AERO 27 MPH NNE RMY 26 9/18 73/47/60/-2/0.00/726/98 18 W AERO 18 MPH WSW RMY 20 9/19 78/51/65/+3/0.00/.../.. 17 WSW AERO 16 MPH WSW RMY 18 9/20 78/54/66/+4/0.00/.../.. 18 SSW AERO 18 MPH SSW RMY 23 9/21 74/57/66/+4/0.00/.../.. 35 S AERO 40 MPH S RMY N/A 9/22 morning low temp: 60F; the normal low is now 52F 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 9/11 - TIED DAILY RECORD MAXIMUM HIGH TEMPERATURE OF 93F; ties record of 93F set in 1983 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 22 HIGH 90F IN 1895, 1914 LOW 30F IN 1904 (Earliest freeze) PRECIP 1.16 INCHES IN 2001 PEAK GUST 60 MPH SSW IN 1989 RECORDS FOR SEPTEMBER 23 HIGH 93F IN 1895,1914 LOW 33F IN 1904 PRECIP 2.67 INCHES IN 1994 PEAK GUST 62 MPH SSW IN 1989 TODAY'S REPORT PREPARED BY: Jonathan O'Brien