BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, DECEMBER 20, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME The very mild temperatures of yesterday averaged 10 degrees warmer than normal and pushed the monthly average up to 6.4 degrees above normal. Warmer than normal temperatures continue with a morning low of 30F running 8 degrees above normal. Today's maximum of 42F is 4 degrees warmer than average. Through the first 18 days accumulated departures are +119 in 2011 and +115 degrees December, 2011, went on to become our second warmest December on record at 37.5 degrees. The warmest December is 38.1 degrees in 2006. Today's observations: 7 A.M. Weather: Clear, stratocumulus layer N-E-SSE, few stratocumulus lenticularis ENE-E, few stratocumulus offshore distant SSW, few altocumulus lenticularis disnt SSE-S Temperature: 31F; Dew Point: 28F; Wind: N at 9 kts, Sea-level pressure: 30.15 ins. Hg, rising then more rapidly Visibility: 60 miles, distant haze all quadrants, virga distant offshore NE-SE 6-hour min. temp: 30F BHO SA 1155 CLR 60 211/31/28/3509/015/ FEW SCSL ENE-E SC LYR XTDNG N-NE-SSE VIRGA DSNT OFFSHR NE-SE FEW SC DSNT OFFSHR SSW FEW ACSL DSNT S-SSW DSNT HZ ALQDS/ 8/540 53020 10036 20030 10 A.M. Weather: Overcast stratocumulus with numerous breaks in the overcast, higher cirrus visible distant SW, virga distant offshore NE-SE Temperature: 35F; Dew Point: 29F; Wind: NW at 5 kts, Sea-level pressure: 30.21 ins. Hg, rising then more slowly Visibility: 60 miles, virga distant offshore NE-SE, distant haze, visibility NW 70, montain in cloud 70 NW BHO SA 1455 E28 OVC 60 231/35/29/3105/021/ NMRS BINOVC ALQDS FEW CI VSB DSNT SW BND MSTLY CLR SKY XTDNG SSW-WNW VIRGA OFFSHR DSNT NE-ESE VSBY NW 70 MTN INCLD 70 NW LGT DSNT HZ/ 8/501 51020 1 P.M. Weather: Scattered cirrus and dense cirrus S-SW invading sky, stratocumulus all quadrants, few lower cumulus and moderate cumulus, virga distant offshore NE-SE Temperature: 42F; Dew Point: 28F; Wind: ENE at 11 kts, Wind: Wind direction gradually veering Sea-level pressure: 30.15 ins Hg, falling then more rapidly Visibility: 60 miles 6-hour max. temp: 42F 6-hour min. temp: 30F BHO SA 1755 220 SCT 60 211/42/28/0611/015/ SC ALQDS FEW LWR CU/MDT CU ALQDS CI/DNS CI S-SW INVDNG VIRGA OFFSHR DSNT NE-SE DSNT HZ WND GRDLY VEERING/ 8/802 58020 10042 20030 WEATHER SUMMARY FOR WEDNESDAY, DECEMBER 19 TEMPERATURE (DEGREES F) MAX.....44 NORMAL.....38 MIN.....35 NORMAL.....23 MEAN....40 NORMAL.....30 DEPARTURE FROM 30-YEAR NORMAL....................+10 TOTAL DEPARTURE FOR THE MONTH...................+125 [+6.4 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............25 DEPARTURE........-10 TOTAL HEATING UNITS FOR THE MONTH...........476 DEPARTURE.......-127 TOTAL HEATING UNITS FOR THE SEASON.........1626 DEPARTURE.......-238 TOTAL HEATING UNITS LAST SEASON TO DATE....1401 DIFFERENCE......+225 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............42 WNW AT 10:06 A.M. AERO....................42 WNW AT 10:06 A.M. ASOS....................41 NW AT 10:04 A.M. DAVIS...................42 WNW AT 10:06 A.M. RMY: 43 THE FASTEST MILE FOR YESTERDAY.............28 NNW AT 3:49 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE..............28 NNW AT 3:49 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............27 NW AT 3:48 P.M. AVERAGE WIND SPEED AND DIRECTION.........18.3 NW ASOS..................17.6 DAVIS.................15.8 NW [310 deg.] * last of several occurrences.... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...trace DEPARTURE..........-0.15 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........2.62 DEPARTURE..........-0.46 ASOS..............2.67 TOTAL PRECIPITATION FOR THE YEAR..........37.50 DEPARTURE.........-14.11 ASOS.............37.56 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..........-6.3 TOTAL SNOWFALL FOR THE SEASON..............6.9 DEPARTURE..........-2.9 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 morning low temp: 30F; the normal low is now 22F 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 20 HIGH 61 IN 1957 LOW -16 IN 1942 PRECIP 1.69 INS. IN 1936 SNOWFALL 13.7 INS. IN 2009 PEAK GUST 75 MPH S IN 2002 RECORDS FOR DECEMBER 21 HIGH 60 IN 1957 LOW -10 IN 1942 PRECIP 2.01 INS. IN 1946 SNOWFALL 11.4 INS. IN 1954 PEAK GUST 77 MPH SSE IN 1957 TODAY'S REPORT PREPARED BY: Robert Skilling/Patrick Peters