BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, DECEMBER 10, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME LOW TEMPERATURE DROPS TO 9F CLOUDS INCREASING The low temperature reached 9F this morning. This marked the first single-digit temperature reading since 9F on January 31, 2010. Thursday's average temperature was 13 degrees below average! This was the largest below average daily temperature departure since January 30, 2010. That day also happened to be the coldest day of 2010 thus far, based on average daily temperature. Today will be another double-digit below average day, with a low of 9F this morning and a high through 1PM of 24F. Clouds are increasing today ahead of a very weak area of low pressure. Little if any precipitation is expected here from this system. With that in mind, precipitation is needed. Since November 11 (29 days), we have received 1.66 inches (37%) of precipitation. The longest stretch of days (297) with low temperatures 21F or higher ended December 7. Longest continuous periods at Blue Hill with temperature of 21F or higher: 1) 297 days (Feb 14 - Dec 7, 2010) 2) 292 days (Mar 1 - Dec 17, 1973) 3) 284 days (Feb 24 - Dec 4, 1902) 4) 283 days (Feb 22 - Dec 1, 1945) 5) 279 days (Feb 22 - Nov 27, 1931) 279 days (Feb 24 - Nov 29, 1958) Today's observations: 7 A.M. Weather: Scattered altocumulus, broken thin cirrus, stratocumulus layer with moderate cumuliform tops NNE-SE, altocumulus and few altocumulus lenticularis SE-SW-NNW, cirrus layer ESE-SW-NNW and overhead invading sky, light distant haze Temperature: 10F, Dew point: 5F; Wind: NW at 9 kts Sea-level pressure: 30.43 inches Hg, rising Visibility: 45 miles, light distant haze 6-hour minimum temp: 9F BHO SA 1155 100 SCT 250 –BKN 45 305/10/5/3109/043/ SC LYR MDT CUFRM TOPS NNE-SE AC AND FEW ACSL SE-SW-NNW CI LYR ESE-SW-NNW AND OVHD INVDNG SKY LGT DSNT HZ/ 8/846 52010 100XX 20009 10 A.M. Weather: Scattered cirrostratus, broken thin cirrus, stratocumulus layer with moderate cumuliform tops NE-ESE, few altocumulus/ altocumulus lenticularis distant NNW-N, patches of dense cirrus SE-SW-WNW, thin smoke layer distant WNW-N-ENE, partial halo, light distant haze Temperature: 16F, Dew point: 9F; Wind: Estimated W at 2 kts, Wind: Light and variable Sea-level pressure: 30.44 inches Hg, rising slightly Visibility: 45 miles, light distant haze BHO SA 1455 200 SCT 250 –BKN 45 308/16/9/E2702/044/ SC LYR MDT CUFRM TOPS NE-ESE FEW AC/ACSL DSNT NNW-N PTCHS DNS CI SE-SW-WNW THN K LYR DSNT WNW-N-ENE LGT DSNT HZPARTIAL HALO WND LGT AND VRB/ 8/847 50003 1 P.M. Weather: Broken altocumulus, broken cirrostratus, broken cirrus, stratocumulus layer with moderate cumuliform tops NNE-SE, few altocumulus lenticularis N and ESE-SW, patches of dense cirrus N-SE, thin smoke layer distant N-NE, light distant haze Temperature: 23F, Dew point: 10F; Wind: SSW at 4 kts, Wind: Light and variable Sea-level pressure: 30.39 inches Hg, falling 6-hourly max. temp: 24F Visibility: 60 miles, light distant haze BHO SA 1755 E120 BKN 200 BKN 250 BKN 60 291/23/10/2104/039/ SC LYR MDT CUFRM TOPS NNE-SE FEW ACSL N AND ESE-SW PTCHS DNS CI N-SE THN K LYR DSNT N-NE LGT DSNT HZ WND LGT AND VRB/ 8/847 58017 10024 20010 WEATHER SUMMARY FOR THURSDAY, DECEMBER 9 TEMPERATURE (DEGREES F) MAX.....26 NORMAL.....40 MIN.....14 NORMAL.....26 MEAN....20 NORMAL.....33 DEPARTURE FROM 30-YEAR NORMAL...............-13 TOTAL DEPARTURE FOR THE MONTH...............-26 [-3.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............45 DEPARTURE.......+13 TOTAL HEATING UNITS FOR THE MONTH...........300 DEPARTURE.......+27 TOTAL HEATING UNITS FOR THE SEASON.........1460 DEPARTURE......-102 TOTAL HEATING UNITS LAST SEASON TO DATE....1400 DIFFERENCE......+60 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..............29 WNW AT 5:28 P.M. AEROVANE...............33 WNW AT 5:28 P.M. ASOS.................. 30 WNW AT 5:28 P.M. DAVIS..................31 WW AT 5:28 P.M. THE FASTEST MILE FOR YESTERDAY............20 WNW AT 5:28 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE.............20 WNW AT 5:29 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE............21 W AT 5:29 P.M. AVERAGE WIND SPEED AND DIRECTION..........13.5 WNW ASOS...................12.8 DAVIS..................12.7 W [269 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE........-0.15 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........0.49 DEPARTURE........-0.86 ASOS..............0.53 TOTAL PRECIPITATION FOR THE YEAR..........58.52 DEPARTURE.......+10.51 ASOS.............58.44** ** 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.....-0.3 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE.....-2.3 TOTAL SNOWFALL FOR THE SEASON...............0.1 DEPARTURE.....-5.1 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 our morning low temp: 9F; the normal low is now 25F NEW DAILY RECORDS FOR DECEMBER 2010 None DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR DECEMBER 10 HIGH 62 IN 1946 LOW -6 IN 1902 PRECIP 1.67 INS. IN 1907 SNOWFALL 6.0 INS. IN 1905 PEAK GUST 66e SW IN 1940 RECORDS FOR DECEMBER 11 HIGH 63 IN 1911 LOW -1 IN 1988 PRECIP 2.36 INS. IN 1992 SNOWFALL 6.0 INS. IN 1894 PEAK GUST 78 S IN 1969 TODAY'S REPORT PREPARED BY: Sean Fankhauser