BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, OCTOBER 13, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME NEW RECORD LOW TEMPERATURE OF 29 THIS MORNING... VERY SUNNY WITH FEW CLOUDS AND EXCELLENT VISIBILITY NEAR 90 MILES... A strong area of high pressure brought in a very cold air mass this morning with many areas dropping into the 20s or low 30s. The low temperature on the summit of Great Blue Hill today was 29 deg F, which establishes a new record minimum temperature for the date. The previous record was 30F recorded in 1934, 1936 and 1988. The low temperature of 29 was recorded in the Hazen shelter at about 6:30 AM EDT, while ASOS reported a low of 30F. The low of 29 is the coldest reading since 24F on 27 March 2012. It has been a long time since a record low temperature has been recorded here. For the month of October the last record low temperature was 28F on October 11, 1993. The last low temperature records for any month were set on March 6th and March 9th in 2007. The sky has been almost completely free of clouds today except for a few stratocumulus offshore and a few cirrus that began to move in from the west at mid-afternoon. Due to the very dry air with the dew point temperature in the middle 20s, the visibility has been spectacular near 90 miles most of the day. Today's observations: 7 A.M. Weather: Clear, few stratocumulus offshore distant NE-SE, few cumulus fractus NW Temperature: 33F; Dew Point: 25F; Wind: NW at 13 kts, Sea-level pressure: 30.45 ins. Hg, rising Visibility: 90 miles 24-hour precip: 0.04 6-hour min. temp: 29F BHO SA 1155 CLR 90 310/33/25/3013/045/ FEW SC OFFSHR DSNT NE-SE FEW CUFRA NW/ 8/500 51010 70004 10033 20029 10 A.M. Weather: Clear, few stratocumulus offshore distant NE-SSE Temperature: 44F; Dew Point: 24F; Wind: WNW at 8 kts, Wind: Direction variable WSW to NNW Sea-level pressure: 30.46 ins. Hg, rising Visibility: 90 miles BHO SA 1455 CLR 90 316/44/24/2908/046/ FEW SC OFFSHR DSNT NE-SSE WND 24V34/ 8/500 50006 1 P.M. Weather: Clear, few cirrus distant WSW-WNW Temperature: 49F; Dew Point: 23F; Wind: NW at 10 kts, Wind: Direction variable SW-WNW Sea-level pressure: 30.40 ins. Hg, falling Visibility: 85 miles 6-hour max. temp: 50F BHO SA 1755 CLR 85 296/49/23/2610/040/ FEW CI DSNT WSW-WNW WND 23V30/ 8/001 58020 10050 20033 WEATHER SUMMARY FOR FRIDAY, OCTOBER 12 TEMPERATURE (DEGREES F) MAX.....51 NORMAL.....62 MIN.....34 NORMAL.....44 MEAN....43 NORMAL.....53 DEPARTURE FROM 30-YEAR NORMAL....................-10 TOTAL DEPARTURE FOR THE MONTH.....................+6 [+0.3 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............22 DEPARTURE.......+10 TOTAL HEATING UNITS FOR THE MONTH...........115 DEPARTURE.......-10 TOTAL HEATING UNITS FOR THE SEASON..........214 DEPARTURE.......-53 TOTAL HEATING UNITS LAST SEASON TO DATE.....153 DIFFERENCE......+61 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............32 NW AT 4:01 P.M. AERO..................30 NW AT 4:01 P.M. ASOS..................31 NW AT 4:01 P.M. DAVIS.................28 NW AT 4:05 P.M. RMY 30 THE FASTEST MILE FOR YESTERDAY...........20 NW AT 4:05 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............21 NW AT 10:01 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........20 NW AT 9:04 A.M. AVERAGE WIND SPEED AND DIRECTION.......13.5 NW ASOS................13.0 DAVIS...............12.3 W [274 deg] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.04 DEPARTURE...........-0.11 ASOS..............0.04 TOTAL PRECIPITATION FOR THE MONTH..........0.83 DEPARTURE...........-0.95 ASOS..............0.78 TOTAL PRECIPITATION FOR THE YEAR..........29.45 DEPARTURE..........-11.41 ASOS.............29.33 PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 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 10/1 66/47/57/0/T/429/61 36 W AERO 35 MPH WSW RMY 36 10/2 69/53/61/+4/0.12/098/14 18 W AERO 16 MPH W RNT 16 10/3 62/58/60/+4/0.02/000/00 20 NE AERO 18 MPH NE RMY 18 10/4 61/58/60/+4/0.08/000/00 17 NNE AERO 14 MPH NE RMY 14 10/5 75/57/66/+10/0.00/623/90 20 SW AERO 19 MPH SW RMY 21 10/6 77/48/63/+8/0.20/269/39 36 SSW AERO 37 MPH SSW RMY 36 TSTM 10/7 57/44/51/-4/0.15/105/27 21 WNW AERO 18 MPH WNW RMY 19 10/8 55/40/48/-6/0.00/328/48 17 WNW AERO 15 MPH WNW RMY N/A 10/9 56/49/53/-1/T/000/00 27 E AERO 25 MPH ENE RMY 25 10/10 60/47/54/0/0.22/000/00 36 WNW AERO 36 MPH WNW RMY 31 10/11 58/41/50/-3/0.00/668/99 35 WNW AERO 33 MPH WNW RMY 34 10/12 51/34/43/-10/0.04/.../.. 32 WNW AERO 30 MPH NW RMY 30 10/13 morning low temp: 29F; the normal low is now 44F DAILY RECORDS FOR OCTOBER 2012 10/13: NEW DAILY RECORD LOW MINIMUM TEMPERATURE 29F; breaks previous record of 30 set in 1934, 1936 and 1988 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR OCTOBER 13 HIGH 84F IN 1930,1954 LOW 29F IN 2012 PRECIP 5.92 INCHES IN 1895 SNOWFALL 4.2 INCHES IN 1934 PEAK GUST 46e MPH W IN 1950 RECORDS FOR OCTOBER 14 HIGH 79F IN 2000 LOW 28F IN 1958 PRECIP 2.69 INCHES IN 1990 SNOWFALL 2.0 INCHES IN 1913 PEAK GUST 63e W IN 1976 TODAY'S REPORT PREPARED BY: Mike Iacono