BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, JANUARY 18, 2010 MLK DAY ALL TIMES ARE IN EASTERN STANDARD TIME RAIN CHANGED TO SNOW THEN TO ICE PELLETS OVERNIGHT WITH AN ACCUMULATION OF ONE INCH DURING THE EARLY A.M. GUSTY NORTHERLY WINDS REACHED PAST 40 MPH WELL OVER ONE INCH OF MELTED PRECIPITATION Rain changed to ice pellets and freezing rain during the early morning hours after a half inch of liquid precipitation had fallen by midnight last night with temperatures in the mid-30's during the evening. A continued temperature drop to 33 degrees and then finally down to 30 to 32 degrees brought a change of mostly ice pellets (sleet) along with some freezing rain causing a glazing condition. The 1.1 inches of solid precipitation including the rainfall last evening and melted sleet totaled 1.30 inches of liquid by 7 a.m. A change to light snow occurred just before 7 a.m. and put down a light accumulation of a half inch of snow and sleet by 10 a.m. after more snow and sleet started after 9 a.m. An additional 0.8 inch snowfall from 7 a.m. to 1 p.m. brings the daily total to 1.9 inches. Northerly winds reached peak gusts of 40 to 46 MPH mostly between the hours of 2 a.m. and 5 a.m. Today's observations: 7 A.M. Weather: Overcast strafractus ceiling raggad, light snow and fog occurring, ice pellets and freezing rain ended during the past hour, total new snow accumulation 1.1 inches Temperature: 30F, Dew point: 30F, Wind: N at 18G33 kts, Wind: Peak wind gust 34 kts N at 6:00 a.m., Wind: Direction variable NW to NNE Sea-level pressure: 29.58 inches Hg, rising Visibility: 2 miles, light snow and fog 6-hour minimum temp: 30F Average snow depth: 5 inches BHO SA 1155 E5 OVC 2S-F 017/30/30/3618G33/958/ CIG RGD ZRIPESB45 PK WND 3534/1000/ WND 31V03 TOTAL NEW SNW PST 24 HRS 1.1 INS THN GLZ ALL SFCS/ 8/7// 4/005 53002 ASOS 60074 ASOS 70138 MANUAL 6//// MANUAL 70130 10033 20030 10 A.M. Weather: Low overcast stratus fractus Temperature: 30F, Dew point: 30F, Wind: NNW at 17G28 kts, Wind: Peak wind from N at 33 kts at 12 past the hour Sea-level pressure: 29.67 inches Hg, rising Visibility: 2 miles light ice pellets, snow grains and fog BHO SA 1455 E5 OVC 2IP-SG-F 047/30/30/3416G28/967 SIPB10 PK WND 3533/17/ WND 30V01/ TOTAL NEW SNW 3 HRS 0.5 IN/ 8/7// 53030 ASOS 60010 MANUAL 6/010 1 P.M. Weather: Low overcast stratus fractus, very light snow and fog Temperature: 30F, Dew point: 29F, Wind: NNW at 16G24 kts, Wind: Peak wind from NNW at 30 kts at 23 past the hour, Wind: Direction variable WNW to NNED Sea-level pressure: 29.70 inches Hg, rising Visibility: 2 miles very light snow and fog BHO SA 1755 E7 OVC 6S-F 058/30/29/3416G24/970/ PK WND 3430/23/ WND 29V02 PCPN VRY LGT TOTAL NEW SNW PST 6 HRS 0.8 IN/ 8/7// 53011 ASOS 60023 MANUAL 6/026 10031 20030 WEATHER SUMMARY FOR SUNDAY, JANUARY 17 TEMPERATURE (DEGREES F) MAX.....40 NORMAL.....33 MIN.....30 NORMAL.....18 MEAN....35 NORMAL.....26 DEPARTURE FROM 30-YEAR AVERAGE.............+9 TOTAL DEPARTURE FOR THE MONTH.............-19 [-1.3 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............30 DEPARTURE........-9 TOTAL HEATING UNITS FOR THE MONTH...........677 DEPARTURE.......+20 TOTAL HEATING UNITS FOR THE SEASON.........2921 DEPARTURE.......-65 TOTAL HEATING UNITS LAST SEASON TO DATE....2979 DIFFERENCE......-58 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............36 NNE AT 11:59 P.M. * AEROVANE..............36 NE AT 10:47 P.M. ASOS..................37 NE AT 10:54 P.M. DAVIS.................36 NE AT 10:53 P.M. THE FASTEST MILE FOR YESTERDAY...........27 NE AT 10:31 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............26 NE AT 10:22 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........27 ENE AT 10;31 P.M. AVERAGE WIND SPEED AND DIRECTION.......11.6 E ASOS................11.1 DAVIS...............11.1 ENE [060 DEG] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....1.30 DEPARTURE....+1.14 ASOS..............1.39 TOTAL PRECIPITATION FOR THE MONTH..........2.14 DEPARTURE....-0.50 ASOS..............2.13 TOTAL PRECIPITATION FOR THE YEAR...........2.14 DEPARTURE....-0.50 ASOS..............2.13 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........1.1 DEPARTURE.....+0.6 TOTAL SNOWFALL FOR THE MONTH...............11.8 DEPARTURE.....+3.3 TOTAL SNOWFALL FOR THE SEASON..............41.6 DEPARTURE....+19.5 PRELIMINARY CLIMATE SUMMARY FOR JANUARY 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 1/1 31/23/27/0/0.01/0.1/005/01 24 NW 1/2 28/19/24/-3/0.45/5.7/000/00 53 W AERO 55 W 1/3 25/13/19/-8/0.34/4.3/000/00 45 W AER0 44 W 1/4 32/20/26/-1/0/0/397/72 35 W AERO 28 W 1/5 29/18/24/-3/0/0/000/00 29 WNW 1/6 30/17/24/-2/0/0/554/100 33 W 1/7 37/21/29/+3/0/0/549/99 31 W 1/8 25/16/21/-5/0.04/0.6/000/00 22 WNW 1/9 25/10/18/-8/0/0/557/100 31 WNW 1/10 26/5/16/-10/0/0/508/91 23 WNW 1/11 33/12/23/-3/0/0/526/94 21 W 1/12 32/12/22/-4/0/0/146/26 36 WNW AERO 33 WNW 1/13 28/9/19/-7/T/T/303/54 28 WNW AERO 31 WNW 1/14 36/19/28/+2/0/0/486/86 25 S 1/15 44/28/36/+10/0/0/.../.. 35 W 1/16 45/29/37/+11/0/0/.../.. 28 WSW 1/17 40/30/35/+9/../0/.../.. 36 NNE 1/18 our morning low temp: 30F; the normal low is now 18F DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR JANUARY 18 HIGH 62F IN 1973,1990 LOW -10F IN 1982 PRECIP 1.68 INS. IN 1915 SNOWFALL 13.0 INS. IN 1948 PEAK GUST 85 MPH SSE IN 2006 RECORDS FOR JANUARY 19 HIGH 59F IN 1973 LOW -11F IN 1887 PRECIP 2.34 INS. IN 1936 SNOWFALL 10.5 INS. IN 1936 PEAK GUST 93e MPH WNW IN 1943 TODAY'S REPORT PREPARED BY: Robert Skilling