BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, SEPTEMBER 24, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME COOL, RELATIVELY CALM, AND MOSTLY CLEAR The low temperature this morning of 40F tied the lowest temperature observed so far this Fall season which also occurred only one week ago on the 17th. The afternoon high may reach the mid 60s, but the average temperature for today is will end up several degrees below the 30-year normal for the date. That will push the month of September thus far to 1.0 degree below the 30-year normal. Only a few small cumulus have dotted the sky today along with some high cirrus. The clouds have mostly been to the N through E of the observatory. Winds have been calmer today compared to the past few days, generally averaging around 10-15 mph, with a few gusts near 20 mph. Visibility continues to be great, although some light distant haze has brought it down to 80 miles rather than the 90 miles of yesterday. Today's Observations: 7 A.M. Weather: Scattered thin cirrus, few cumulus distant NE-S and distant WNW-NNW, cirrus distant NNE and distant SW-WNW, thin smoke layer along horizon all quadrants Temperature: 43F; Dew Point: 39F; Wind: W at 10 kts. Sea-level pressure: 29.96 ins. Hg, rising then falling slightly Visibility: 80 miles 6-hr min. temp: 40F BHO SA 1155 250 –SCT 80 145/43/39/2810/996/ FEW CU DSNT NE-S AND DSNT WNW-NNW CI DSNT NNE AND DSNT SW-WNW THN K LYR ALG HRZN ALQDS/ 8/101 58004 10043 20040 10 A.M. Weather: Temperature: 55F; Dew Point: 39F; Wind: NW at 10 kts, Wind: Direction variable W-NNW Sea-level pressure: 29.92 ins. Hg, falling slightly Visibility: 80 miles BHO SA 1455 30 SCT 220 SCT 250 –SCT 80 129/54/41/2810/991/ FEW SML CU FRMG ALQDS PTCHS DNS CI DSNT N-ENE CI DSNT NNW-ENE AND DSNT SSE-SSW LGT DSNT HZ WND 24V31/ 8/102 56016 1 P.M. Weather: Scattered altocumulus, scattered dense cirrus, scattered thin cirrus, few small cumulus distant ENE-SSE, small cumulus distant NW, altocumulus/altocumulus lenticularis distant N-ENE, cirrus and patches of dense cirrus distant NNW-E, patch of cirrus distant SE, light distant haze Temperature: 62F; Dew Point: 43F; Wind: WNW at 7 kts, Wind: Direction variable SW-NW Sea-level pressure: 29.87 ins. Hg, falling Visibility: 80 miles 6-hr max. temp: 64F BHO SA 1755 60 SCT 220 SCT 250 –SCT 80 114/62/43/2907/987/ FEW SML CU DSNT ENE-SSE SML CU DSNT NW AC/ACSL DSNT N-ENE CI AND PTCHS DNS CI DSNT NNW-E PTCH CI DSNT SE LGT DSNT HZ WND 23V32/ 8/142 58015 10064 20043 WEATHER SUMMARY FOR MONDAY, SEPTEMBER 23, 2013 TEMPERATURE (DEGREES F) MAX.....63 NORMAL.....69 MIN.....43 NORMAL.....52 MEAN....53 NORMAL.....60 DEPARTURE FROM 30-YEAR NORMAL.....................-7 TOTAL DEPARTURE FOR THE MONTH....................-13 [-0.8 DEGREE/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY..............0 DEPARTURE.........-1 TOTAL COOLING UNITS FOR THE MONTH.............56 DEPARTURE.........+2 TOTAL COOLING UNITS FOR THE SEASON...........696 DEPARTURE.......+105 TOTAL COOLING UNITS LAST SEASON TO DATE......765 DIFFERENCE.......-69 HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY.............12 DEPARTURE.........+6 TOTAL HEATING UNITS FOR THE MONTH.............81 DEPARTURE........+13 TOTAL HEATING UNITS FOR THE SEASON............93 DEPARTURE..........0 TOTAL HEATING UNITS LAST SEASON TO DATE.......49 DIFFERENCE.......+44 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..................25 NW AT 8:07 A.M. AERO.......................26 NW AT 8:07 A.M. ASOS.......................26 NW AT 8:08 A.M. DAVIS......................24 NW AT 8:13 A.M. RMY 28 FASTEST MILE FOR YESTERDAY....................18 NW AT 8:19 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE.................18 NW AT 8:22 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE................17 NW AT 8:22 A.M. AVERAGE WIND SPEED AND DIRECTION............11.9 NW ASOS.....................10.6 DAVIS....................10.1 NW [314 degrees] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE.............-0.14 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........3.91 DEPARTURE.............+0.88 ASOS..............4.04 TOTAL PRECIPITATION FOR THE YEAR..........41.92 DEPARTURE.............+3.87 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/+3/0.00/731/99 17 WSW AERO 16 MPH WSW RMY 18 9/20 78/54/66/+4/0.00/706/96 18 SSW AERO 18 MPH SSW RMY 23 9/21 74/57/66/+4/T/512/70 35 S AERO 40 MPH S RMY N/A 9/22 70/49/60/-1/0.39/365/50 38 S AERO 39 MPH S RMY 42 9/23 63/43/53/-7/0.00/.../.. 25 NW AERO 26 MPH NW RMY 28 9/24 morning low temp: 40F; 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 24 HIGH 87F IN 1959 LOW 33F IN 1885,1950,1963 PRECIP 1.19 INCHES IN 1955 PEAK GUST 54e MPH SW IN 1940 RECORDS FOR SEPTEMBER 25 HIGH 87F IN 1970 LOW 31F IN 1950 PRECIP 2.68 INCHES IN 1961 PEAK GUST 63 MPH SSW IN 1991 TODAY'S REPORT PREPARED BY: Sean Fankhauser