BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA   DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, DECEMBER 19, 2006  ALL TIMES ARE IN EASTERN STANDARD TIME   SUNNY AND MUCH COOLER WEATHER TODAY YESTERDAY WAS LAST OF SIX DAYS IN A ROW MORE THAN 10 DEGREES WARMER THAN NORMAL DRY DECEMBER CONTINUES--NOW ALMOST 2 INCHES BELOW NORMAL--JUST 5 DAYS HAVE HAD MEASURABLE PRECIPITATION   The overcast, gloomy weather of yesterday has been been replaced by very sunny conditions today. Temperatures have finally cooled after a six-day stretch during which each day averaged between 12 and 18 degrees warmer than normal from December 13-18. A total of 13 out of 18 days with above normal temperatures this month has pushed the average up to 40 degrees or 7 degrees above normal to date.   Today's observations:   7 A.M. Weather: High thin scattered clouds northeast thru south-southwest sky clearing. Temperature: 32F, Dew point: 20F, Wind: WNW at 11 kts Sea-level pressure: 30.19 inches Hg, rising Visibility: 60-70 miles 6 hour min. temp. 32 deg; 24 hour rainfall: 0.01 in. BHO SA 1155 180 SCT 250 –SCT 60 222/32/20/2911/019/ SC ALG/OFFSHR NE-SE SKY CLRG EDGE OVHD SKY MSTLY CLR W-N VSBY NW 70/ 8/571 53009 ASOS 70002 MANUAL 70001 10038 20032    10 A.M.    Weather: Clear, few distant clouds  Temperature: 37F, Dew point: 17F, Wind: WNW at 10 kts Sea-level pressure: 30.20 inches Hg, falling Visibility: 80 miles   BHO SA 1455 CLR 80 228/37/17/3010/020/ SC DSNT NW-N-ESE CI DSNT ESE-SSW-SSW/ 8/501 50006   1 P.M.    Weather: Clear, stratocumulus except southeast thru southwest Temperature: 41F, Dew point: 18F, Wind: SW at 13G20 kts Sea-level pressure: 30.14 inches Hg, falling Visibility: 75 miles BHO SA 1755 CLR 75 206/41/18/2813G20/014/ SC XCPT SE-SW FEW CI DSNT WSW-N WND 25V31/ 8/501 56022 10041 20032   WEATHER SUMMARY FOR MONDAY, DECEMBER 18    TEMPERATURE (DEGREES F) MAX.....52   NORMAL.....38 MIN.....38   NORMAL.....23   MEAN....45   NORMAL.....30 DEPARTURE FROM 30-YEAR NORMAL.......+15   TOTAL DEPARTURE FOR THE MONTH.......+131 [+7.1 DEG/DAY]   HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..........20   DEPARTURE.....-14 TOTAL HEATING UNITS FOR THE MONTH.........425   DEPARTURE....-126 TOTAL HEATING UNITS FOR THE SEASON.......1498   DEPARTURE....-362 TOTAL HEATING UNITS LAST SEASON TO DATE..1739   DIFFERENCE...-241   PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...........29  W  AT 7:26 P.M.                                AEROVANE............28  W  AT 7:31 P.M.                                       ASOS................25 WNW AT 11:36 P.M.                                    DAVIS...............29  SW AT 1:15 A.M.            FASTEST MILE FOR YESTERDAY.............21  W  AT 7:33 P.M.*     MAXIMUM 2-MINUTE ASOS AVERAGE..........21  W  AT 7:33 P.M.     MAXIMUM 2-MINUTE DAVIS AVERAGE.........22  W  AT 6:50 P.M.              AVERAGE WIND SPEED AND DIRECTION.......12.0                    ASOS................12.5                              DAVIS...............12.2 WSW [250 deg.] * last of several occurrences..   PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M... 0.01  DEPARTURE.....-0.13                          ASOS..............0.02 TOTAL PRECIPITATION FOR THE MONTH..........0.85  DEPARTURE.....-1.78                          ASOS..............0.88    TOTAL PRECIPITATION FOR THE YEAR..........58.95  DEPARTURE.....+9.81                          ASOS.............58.48   SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0   DEPARTURE.....-0.4 TOTAL SNOWFALL FOR THE MONTH................3.2   DEPARTURE.....-2.7 TOTAL SNOWFALL FOR THE SEASON...............3.2   DEPARTURE.....-5.6   PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2006......CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST   AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available   12/1  65/59/62/+26/0.42/0.0/000/00   63 S    Aero 65 S 12/2  60/35/48/+12/0/0/0/551/99      47 W    Aero 44 W 12/3  44/29/37/+2/0/0/0/506/91       29 S 12/4  38/25/32/-3/0.28/3.2/344/62    38 WNW  Aero 40 WNW 12/5  32/22/27/-8/0/0/255/46         23 W 12/6  44/21/33/-1/0/0/171/31         43 SSE  Aero 41 SSE 12/7  53/33/43/+9/T/T/435/79         37 W 12/8  33/17/25/-8/T/T/215/39         45 W    Aero 46 WNW 12/9  36/19/28/-5/0/0/341/62         31 SSW                    12/10 51/32/42/+9/0/0/516/94         35 SSW 12/11 47/35/41/+9/T/0/077/14         25 WSW  12/12 42/30/36/+4/0/0/400/73         28 SSE 12/13 50/37/44/+12/0/0.11/005/01     31 SE 12/14 56/42/49/+18/0/0/410/75        25 S 12/15 52/42/47/+16/0/0/000/00        31 S 12/16 50/35/43/+12/0.03/0/.../..     35 W        12/17 53/33/43/+12/0/0/.../..        35 SSW 12/18 52/38/45/+15/0.01/0/.../..     29 W   12/19 morning low temp: 32 deg; normal low now 23 deg.         NEW DAILY RECORDS SO FAR THIS MONTH 12/1- New daily and monthly record high minimum temperature 59;       previous daily record 50 in 1908 and 1934, previous       monthly record 53 on 4 and 6 December 1982 and on       22 and 23 December 1990.       In addition: NEW HIGHEST MINIMUM TEMPERATURE SO LATE IN YEAR,       59 deg; previous record 57 deg. 11/17/1927.   DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated):   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   RECORDS FOR DECEMBER 20 HIGH 61 IN 1957 LOW -16 IN 1942 PRECIP 1.69 INS. IN 1936 SNOWFALL 8.3 INS. IN 1995 PEAK GUST 75 MPH S IN 2002   TODAY'S REPORT By: Robert Skilling