BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, DECEMBER 18, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME SUNNY AND SEASONABLE WEATHER TODAY... For the first time since last Monday, the temperature will be close to or just below the average for mid-December with a low of 22 this morning and a high in the middle 30s. A few clouds partially blocked the sun this morning, but the sky has become mostly sunny as of mid-day. The visibility has gradually increased to 45 miles at 1 PM. As of Friday, the month has now become drier than average, and the snowfall departure for the season is approaching eight inches below average. Today's observations: 7 A.M. Weather: Scattered stratocumulus, broken altocumulus translucidus, few stratocumulus distant offshore NE-SE, few cumuloform tops ENE-E Temperature: 23F, Dew point: 20F; Wind: WSW at 10 kts Sea-level pressure: 30.08 inches Hg, rising Visibility: 25 miles, light distant haze 6-hour minimum temp: 22F Total snow depth: trace BHO SA 1155 45 SCT 120 SCT 25 186/23/20/2510/008/ SC OFFSHR DSNT NE-SE FEW CUFRM TOPS ENE-E DSNT HZ ALQDS/ 8/530 53010 10023 20022 10 A.M. Weather: Broken stratocumulus, broken altocumulus translucidus, few stratocumulus distant E Temperature: 30F, Dew point: 22F; Wind: WNW at 5 kts, Wind: Light and variable Sea-level pressure: 30.11 inches Hg, rising Visibility: 35 miles, smoke layer N-NE, distant haze SW-N BHO SA 1455 E55 BKN 100 BKN 35 195/30/22/2905/011/ FEW SC DSNT E K LYR N-NE DSNT HZ SW-N WND LGT AND VRB/ 8/530 50009 1 P.M. Weather: Scattered cumulus, few cumulus fractus, few cirrus SE-SSW Temperature: 36F, Dew point: 21F; Wind: W at 5 kts, Wind: Light and variable Sea-level pressure: 30.06 inches Hg, falling Visibility: 45 miles, light haze NW-NE 6-hourly max. temp: 36F BHO SA 1755 45 SCT 45 180/36/21/2705/006/ FEW CUFRA FEW CI SE-SSW LGT HZ NW-NE WND LGT AND VRB/ 8/101 58015 10036 20023 WEATHER SUMMARY FOR FRIDAY, DECEMBER 17 TEMPERATURE (DEGREES F) MAX.....34 NORMAL.....38 MIN.....17 NORMAL.....23 MEAN....26 NORMAL.....31 DEPARTURE FROM 30-YEAR NORMAL.................-5 TOTAL DEPARTURE FOR THE MONTH................-48 [-3.0 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............39 DEPARTURE........+5 TOTAL HEATING UNITS FOR THE MONTH...........589 DEPARTURE.......+52 TOTAL HEATING UNITS FOR THE SEASON.........1749 DEPARTURE.......-77 TOTAL HEATING UNITS LAST SEASON TO DATE....1684 DIFFERENCE......+65 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..............22 WNW AT 2:49 P.M. AEROVANE...............24 WNW AT 2:49 P.M. ASOS...................22 WNW AT 2:50 P.M. DAVIS..................24 W AT 2:01 P.M. THE FASTEST MILE FOR YESTERDAY............17 WNW AT 2:02 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE.............16 WNW AT 2:51 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE............18 W AT 2:04 P.M. AVERAGE WIND SPEED AND DIRECTION.........9.3 WNW ASOS..................8.4 DAVIS.................7.7 W [263 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..........2.43 DEPARTURE........-0.06 ASOS..............2.54 TOTAL PRECIPITATION FOR THE YEAR..........60.46 DEPARTURE.......+11.31 ASOS.............60.45** ** ASOS missing rainfall due to system failure on 6/24-25 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.....-0.4 TOTAL SNOWFALL FOR THE MONTH................0.2 DEPARTURE.....-4.9 TOTAL SNOWFALL FOR THE SEASON...............0.3 DEPARTURE.....-7.7 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2010 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust when significant TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 12/1 55/43/49/+13/0.49/0.0/000/00 55 SE AERO 61 MPH SE 12/2 48/29/39/+3/0.00/0.0/540/100 30 W 12/3 38/29/34/-1/0.00/0.0/050/09 25 WNW 12/4 40/28/34/-1/0.00/0.0/516/93 27 WNW 12/5 34/23/29/-6/0.00/0.0/127/23 24 W 12/6 32/22/27/-7/0.00/0.0/447/81 37 WSW AERO 38 MPH WSW 12/7 33/23/28/-6/0.00/0.0/463/84 35 W AERO 37 MPH W 12/8 31/19/25/-8/0.00/0.0/.../.. 39 W AERO 40 MPH W 12/9 26/14/20/-13/0.00/0.0/.../.. 29 WNW 12/10 25/9/17/-16/0.00/0.0/.../.. 17 SSE 12/11 44/25/35/+3/0.00/0.0/.../.. 23 WSW 12/12 55/33/44/+12/1.57/0.0/000/00 55 SE AERO 69 MPH SE 12/13 55/33/44/+12/0.35/0.0/.../.. 50 SSE AERO 58 MPH SSE 12/14 33/16/25/-6/T/T/.../.. 30 W 12/15 19/13/16/-15/0.02/0.2/.../.. 33 WNW AERO 38 MPH WNW 12/16 32/15/24/-7/0.00/0.0/.../.. 25 SSW 12/17 34/17/26/-5/0.00/0.0/.../.. 22 WNW 12/18 morning low temp: 22F; the normal low is now 23F DAILY RECORDS FOR DECEMBER 2010 12/15 - NEW RECORD LOW MAXIMUM TEMP. OF 19F; this surpasses the previous record of 20F in 1903,1905,1931, and 1962 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR DECEMBER 18 HIGH 59 IN 1928 LOW -11 IN 1919 PRECIP 1.44 INS. IN 1915 SNOWFALL 7.0 INS. IN 1904 PEAK GUST 76e W IN 1978 RECORDS FOR DECEMBER 19 HIGH 59 IN 1899 LOW -1 IN 1919 PRECIP 2.06 INS. IN 1986 SNOWFALL 14.1 INS. IN 1945 PEAK GUST 68 NE IN 1986 TODAY'S REPORT PREPARED BY: Mike Iacono