BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, SEPTEMBER 17, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME COLDEST OF THE SEASON TO DATE..... FIRST LOW TEMPERATURES IN THE 30'S THIS MORNING STRONG RADIATIONAL COOLING...38F, NORWOOD AND TAUNTON MARTHAS VINEYARD AT 39F, NEW BEDFORD AT 41F Strong radiational cooling overnight allowed for the "bottom to drop out of the thermometer" at many tradiationsl cold spots in southeastern Massachusetts. Here atop Blue the low this morning of 51F was 2 degrees above the low of 49F on Sunday morning. Temperatures have warmed nicely to the low 70's by this afternoon with sunshine through just some high cloudiness. Today's observations: 7 A.M. Weather: Thin scattered cirrus, 2 layers Temperature: 54; Dew Point: 44F; Wind: NW at 8 kts Sea-level pressure: 30.10 ins. Hg, rising, then more slowly Visibility: 75 miles, light distant haze 6-hour min. temp: 51F BHO SA 1155 250 –SCT 300 –SCT 60 194/54/44/3208/010/ THN K LYR ALG HRZN SSW-SW THN K LYR ALF SW-NNW VSBY NW 75 DSNT LGT HZ/ 8/001 51014 10055 20051 10 A.M. Weather: Scattered cirrus, thin scattered cirrus, mostly clear sky NW-NNE Temperature: 65F; Dew Point: 47F; Wind: Estimated WNW at 3 kts, Wind: Light Sea-level pressure: 30.11 ins. Hg, rising slightly Visibility: 60 miles, NW 70 miles, light distant haze BHO SA 1455 250 SCT 300 –SCT 60 197/65/47/E3003/011/ MSTLY CLR SKY NW-NNE THN KHZ DSNT NE-ENE/VSBY 30 VSBY NW 70 DSNT LGT HZ WND LGT/ 8/100 50003 1 P.M. Weather: Scattered dense cirrostratus, broken dense cirrostratus, higher thin cirrostatus visible, dense cirrostratus E-S-W, mostly clear sky NW-NE Temperature: 72F; Dew Point: 46F; Wind: SSW @ 7 kts, Wind: Direction variable SE-WSW Sea-level pressure: 30.08 ins. Hg, falling then more rapidly Visibility: 60 miles, light distant haze 6-hour max. temp: 73F BHO SA 220 SCT E250 BKN 300 BKN 60 185/72/46/2107/008/ DENSE CS LYR E-S-W FEW PTCHS DNS CI S MSTLY CLR SKY NW-NE THN K LYR ALG HRZN ENE-E WND 13V24/ 8/006 58012 10073 20054 WEATHER SUMMARY FOR SUNDAY, SEPTEMBER 16 TEMPERATURE (DEGREES F) MAX.....70 NORMAL.....72 MIN.....49 NORMAL.....55 MEAN....60 NORMAL.....63 DEPARTURE FROM 30-YEAR NORMAL.....................-3 TOTAL DEPARTURE FOR THE MONTH....................+20 [+1.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............5 DEPARTURE........+1 TOTAL HEATING UNITS FOR THE MONTH............20 DEPARTURE.......-15 TOTAL HEATING UNITS FOR THE SEASON...........20 DEPARTURE.......-40 TOTAL HEATING UNITS LAST SEASON TO DATE......38 DIFFERENCE......-18 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............23 W AT 3:57 P.M. * AERO..................20 W AT 3:40 P.M. * ASOS..................21 W AT 3:57 P.M. DAVIS.................20 WNW AT 1:49 P.M. RMY 21 THE FASTEST MILE FOR YESTERDAY...........15 W AT 3:41 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............16 W AT 3:58 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........15 W AT 3:15 P.M. AVERAGE WIND SPEED AND DIRECTION........9.4 WNW ASOS.................8.7 DAVIS................8.2 WNW [290 deg] * Last of several occurrences 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..........1.18 DEPARTURE...........-0.84 ASOS..............1.16 TOTAL PRECIPITATION FOR THE YEAR..........26.53 DEPARTURE..........-10.51 ASOS.............26.42 PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 2012 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 75/60/68/0/0.00/637/81 27 ENE AERO 25 MPH ENE RMY 23 9/2 80/60/70/+2/0.00/455/58 21 ENE AERO 20 MPH ENE RMY 20 9/3 76/57/67/0/0.00/485/62 20 SE AERO 20 MPH S RMY 21 9/4 72/62/67/0/0.40/000/00 25 S AERO 23 MPH S RMY N/A 9/5 79/64/72/+5/0.31/171/22 33 SSW AERO 35 MPH SSW RMY 33 9/6 77/62/70/+3/0.00/279/36 20 SSW AERO 20 MPH SSW RMY 19 9/7 85/66/76/+10/0.00/463/60 22 SSW AERO 20 MPH SSW RMY N/A TSTM 9/8 81/62/72/+6/0.38/453/59 45 S AERO 45 MPH S RMY 45 9/9 72/58/65/-1/0.02/283/37 25 WNW AERO 23 MPH WNW RMY N/A 9/10 66/50/58/-7/0.00/313/41 33 NW AERO 32 MPH NW RMY 34 9/11 71/47/59/-6/0.00/714/94 23 NW AERO 21 MPH WNW RMY N/A 9/12 77/53/65/0/0.00/719/95 20 S AERO 18 MPH S RMY 18 9/13 81/59/70/+6/0.00/731/97 21 S AERO 18 MPH S RMY 19 9/14 81/59/70/+6/0.00/.../.. 25 S AERO 23 MPH S RMY 23 9/15 72/54/63/-1/0.07/.../.. 28 NW AERO 27 MPH WNW RMY 27 9/16 70/49/60/-3/0.00/.../.. 23 W AERO 20 MPH W RMY 21 9/17 morning low temp: 51F; the normal low is now 54F DAILY RECORDS FOR SEPTEMBER 2012 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 17 HIGH 86F IN 1915,1941,1991 LOW 38F IN 1959 PRECIP 2.73 INCHES IN 1933 PEAK GUST 60 MPH WNW IN 1999 RECORDS FOR SEPTEMBER 18 HIGH 88F IN 1906 LOW 36F IN 1919 PRECIP 4.25 INCHES IN 1996 PEAK GUST 77e MPH WNW IN 1948 TODAY'S REPORT PREPARED BY: Robert Skillling/Patrick Peters