BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, DECEMBER 24, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME PLEASANT EARLY WINTER DAY WITH ANOTHER DAY OF EXCELLENT VISIBILITY AND MOSTLY SUNNY SKIES Today was a very pleasant day on the summit as mostly clear skies paved way for temperatures in the upper 30's and low 40's across much of the area. Winds have died down noticeably after a couple of gusty days associated with a strong low pressure that has now passed by. Visibility has been up once again, with Grand Monadnock crystal clear out to the WNW, indicating a visibility as high as 85 miles. There have been a few cirrus clouds passing within the vicinity beginning early this afternoon, but have not done much to suppress any sunlight received here on the summit today. Houghton's Pond and Ponkapoag Pond had noticeable ice cover this morning due to such low temperatures overnight. The ice has since melted as the day progressed. The last time both ponds were completely frozen over was on the morning of January 24th. Today's observations: 7 A.M. Weather: Clear, stratocumulus along horizon offshore NNE-E, few cumulus fractus distant NE-ESE, few altocumulus standing lenticularis distant ESE-WSW, contrail E Temperature: 29F; Dew Point: 20F; Wind: W at 10 kts Sea-level pressure: 30.00 ins. Hg, increasing steadily Visibility: 40 miles 6-hour min. temp: 28F BHO SA 1155 CLR 40 159/29/20/2610/000/ SC LYR ALNG HRZN OFFSHR NNE-E FEW CUFRA DSNT NE-ESE FEW ACSL DSNT ESE-SSW CONTRAIL E/ 8/540 52027 10031 20028 10 A.M. Weather: Scattered cirrus fibratus, few stratocumulus distant offshore NNE-E and distant W-NW, few lower cirrus spissatus ESE-WSW, contrails all quadrants Temperature: 34F; Dew Point: 18F; Wind: NW at 12 kts Sea-level pressure: 30.05 ins. Hg, increasing Visibility: 80 miles BHO SA 1455 250 –SCT 80 175/34/18/3212/005/ FEW SC DSNT OFFSHR NNE-E AND DSNT W-NW FEW LWR DNS CI ESE-WSW CONTRAILS ALQDS/ 8/501 50016 1 P.M. Weather: Scattered cirrus spissatus, scattered cirrus fibratus/radiatus, cumulus very distant W, stratocumulus layer very distant offshore NE-E Temperature: 38F; Dew Point: 18F; Wind: W at 7 kts, Wind: Direction variable WSW-NNW Sea-level pressure: 30.03 ins Hg, decreasing Visibility: 85 miles 6-hour max. temp: 39F BHO SA 1755 200 SCT 250 –SCT 85 168/38/18/2807/003/ CU VRY DSNT W SC LYR VRY DSNT OFFSHR NE-E WND 24V34/ 8/101 58007 10039 20028 WEATHER SUMMARY FOR SUNDAY, DECEMBER 23 TEMPERATURE (DEGREES F) MAX.....37 NORMAL.....37 MIN.....25 NORMAL.....21 MEAN....31 NORMAL.....29 DEPARTURE FROM 30-YEAR NORMAL......................+2 TOTAL DEPARTURE FOR THE MONTH....................+150 [+6.3 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............34 DEPARTURE.........-2 TOTAL HEATING UNITS FOR THE MONTH...........593 DEPARTURE.......-152 TOTAL HEATING UNITS FOR THE SEASON.........1743 DEPARTURE.......-264 TOTAL HEATING UNITS LAST SEASON TO DATE....1495 DIFFERENCE......+248 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............44 WNW AT 12:51 A.M. AERO....................44 WNW AT 12:51 A.M. ASOS....................44 WNW AT 12:51 A.M. DAVIS...................38 WNW AT 12:51 A.M. RMY: N/A THE FASTEST MILE FOR YESTERDAY.............30 WNW AT 1:03 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE..............29 W AT 1:03 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............28 W AT 12:52 A.M. AVERAGE WIND SPEED AND DIRECTION.........14.4 W ASOS..................13.5 DAVIS.................12.7 WSW [258 deg.] *...last of several occurrences PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE..........-0.16 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........3.52 DEPARTURE..........-0.19 ASOS..............3.55 TOTAL PRECIPITATION FOR THE YEAR..........38.40 DEPARTURE.........-13.84 ASOS.............38.44 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........0.0 DEPARTURE..........-0.5 TOTAL SNOWFALL FOR THE MONTH...............0.9 DEPARTURE..........-8.3 TOTAL SNOWFALL FOR THE SEASON..............6.9 DEPARTURE..........-4.9 PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 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 12/1 34/25/30/-7/0.08/0.8/000/00 16 E AERO 14 MPH E RMY 16 12/2 52/32/42/+6/0.00/0.0/006/01 32 SSW AERO 32 MPH SSW RMY 34 12/3 57/43/50/+14/0.00/0.0/523/94 31 NW AERO 30 MPH NW RMY 32 12/4 56/40/48/+13/0.03/0.0/000/00 37 S AERO 39 MPH S RMY 38 12/5 56/31/44/+9/0.03/0.0/310/56 38 WNW AERO 37 MPH WNW RMY 40 12/6 38/25/32/-3/0.00/0.0/519/94 31 NW AERO 30 MPH NW RMY N/A 12/7 42/30/36/+2/0.02/0.0/000/00 18 SSW AERO 16 MPH SSW RMY 18 12/8 45/41/43/+9/0.35/0.0/000/00 21 ENE AERO 18 MPH ENE RMY N/A 12/9 45/38/42/+8/0.10/0.0/181/33 24 NNW AERO 24 MPH NNW RMY 25 12/10 59/39/49/+16/0.51/0.0/000/00 32 SSW AERO 33 MPH SSW RMY 35 12/11 54/30/42/+9/0.01/0.0/351/64 25 W AERO 25 MPH W RMY 23 12/12 38/26/32/-1/0.00/0.0/.../.. 20 NW AERO 18 MPH NW RMY N/A 12/13 42/29/36/+4/0.00/0.0/.../.. 18 NW AERO 15 MPH NW RMY N/A 12/14 47/29/38/+6/0.00/0.0/.../.. 28 W AERO 25 MPH W RMY 27 12/15 40/31/36/+4/0.00/0.0/.../.. 24 NNW AERO 22 MPH NNW RMY 21 12/16 36/31/34/+3/0.25/0.1/.../.. 25 E AERO 22 MPH E RMY N/A 12/17 44/36/40/+9/0.65/0.0/000/00 31 ENE AERO 29 MPH ENE RMY 30 12/18 50/40/45/+14/0.61/0.0/000/00 28 E AERO 24 MPH E RMY N/A 12/19 44/35/40/+10/T/0.0/.../.. 42 WNW AERO 40 MPN WNW RMY 43 12/20 42/30/36/+6/T/0.0/.../.. 25 NNW AERO 23 MPH NNW RMY N/A 12/21 53/35/44/+14/0.00/0.0/.../.. 58 E AERO 53 MPH E RMY 57 12/22 37/26/32/+3/T/T/.../.. 47 W AERO 47 MPH W RMY 43 12/23 37/25/31/+2/0.00/0.0/.../.. 44 WNW AERO 44 MPH WNW RMY N/A 12/24 morning low temp: 28F; the normal low is now 21F DAILY RECORDS FOR DECEMBER 2012 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated) RECORDS FOR DECEMBER 24 HIGH 58 IN 1996 LOW -6 IN 1943 PRECIP 2.21 INS. IN 1994 SNOWFALL 12.3 INS. IN 1961 PEAK GUST 79e MPH SE IN 1941 RECORDS FOR DECEMBER 25 HIGH 62 IN 1889 LOW -11 IN 1980 PRECIP 1.37 INS. IN 2002 SNOWFALL 8.5 INS. IN 2002 PEAK GUST 80 MPH NW IN 1971 TODAY'S REPORT PREPARED BY: George Tabeek/Patrick Peters