BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MARCH 17, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME LARGEST SNOWSTORM OF THE SEASON BRINGS 8.5 INCHES OF SNOW AND SLEET ON FRIDAY...FOLLOWED BY HEAVY RAIN TODAY... MORE THAN THREE INCHES OF PRECIPITATION SINCE YESTERDAY... ONE-TENTH INCH OF GLAZE THIS MORNING... The frozen precipitation total at the summit was 8.5 inches of snow and sleet through this morning as measured at midnight last night. Only a trace of sleet was observed after midnight. The rain began shortly before midnight, became heavy during the night with the temperature between 32 and 34 deg F. A melted precipitation total of 3.10 inches was measured in our standard rain gage for the past 24 hours. The temperature has dropped below freezing since 7 AM this morning, and a glaze is forming in the continuing light freezing drizzle. The temperature is 29 as of 9 AM EST. A total of 5 inches of snow remains on the summit this morning. As of 1 PM, there has been an additional 0.07 inch of freezing rain and freezing drizzle leaving a tenth inch of glaze on most surfaces. A thicker glaze of up to 0.5 has accumulated on the metal masts and wires on the roof, causing several of our wind instruments to freeze. The storm total liquid equivalent precipitation is 3.17 inches, with ASOS measuring 3.12 inches. Today's observations: 7 A.M. Weather: Sky obscured in light rain, light drizzle and fog Temperature: 32F, Dew point: 32F, Wind: N at 16G21 kts Sea-level pressure: 29.47 inches Hg, falling Visibility: 1/8 mile, fog 6-hour min. temp. 32 deg. 24-hour precipitation: 3.10 inches 24-hour snowfall: 8.5 inches Snow on ground: 5 inches BHO SA 1155 W3 X 1/8R-L-F 739/32/32/3516G21/947/ TOTAL NEW SNOW PST 24 HRS 8.5 INS/ 8//// 4/005 56024 6//// 70310 10034 20032 10 A.M. Weather: Sky obscured in light freezing drizzle and fog Temperature: 27F, Dew point: 26F, Wind: NW at 15 kts Sea-level pressure: 29.44 inches Hg, falling Visibility: 3/4 mile 3-hourly precipitation: 0.07 inch, including 0.1 inch glaze BHO SA 1455 W4 X 3/4ZL-F 725/27/26/3015/944/ TOTAL GLZ PST 3 HRS 0.1 IN/ 8//// 56014 6007/ 1 P.M. Weather: Sky obscured with fog Temperature: 30F, Dew point: 30F, Wind: W at 7 kts Sea-level pressure: 29.47 inches Hg, rising Visibility: 3/4 mile, variable 1/2 to 1 mile 6-hourly precipitation: 0.07 inch BHO SA 1755 W3 X 3/4VF 735/30/30/2807/947/ VSBY 1/2V1 WND LGT/ 8//// 51010 6007/ 10032 20027 WEATHER SUMMARY FOR FRIDAY, MARCH 16 TEMPERATURE (DEGREES F) MAX.....35 NORMAL.....45 MIN.....24 NORMAL.....28 MEAN....30 NORMAL.....36 DEPARTURE FROM 30-YEAR NORMAL...........-6 TOTAL DEPARTURE FOR THE MONTH..........-12 (-1.0 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..........35 DEPARTURE........+6 TOTAL HEATING UNITS FOR THE MONTH.........509 DEPARTURE.......+10 TOTAL HEATING UNITS FOR THE SEASON.......4600 DEPARTURE......-469 TOTAL HEATING UNITS LAST SEASON TO DATE..4559 DIFFERENCE......+42 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............55 NE AT 10:38 P.M. AEROVANE.............53 NE AT 9:07 P.M. ASOS.................54 ENE AT 9:08 P.M. DAVIS................51 NNE AT 6:36 P.M. FASTEST MILE FOR YESTERDAY..............41 NE AT 9:06 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........39 NE AT 9:08 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........38 NE AT 9:07 P.M. AVERAGE WIND SPEED AND DIRECTION........22.9 NNE ASOS................21.2 DAVIS...............20.7 NE [36 deg] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....3.10 DEPARTURE.....+2.94 ASOS..............3.00 TOTAL PRECIPITATION FOR THE MONTH..........5.17 DEPARTURE.....+2.59 ASOS..............5.10 TOTAL PRECIPITATION FOR THE YEAR..........10.89 DEPARTURE.....-0.53 ASOS.............10.73 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........8.5 DEPARTURE......+8.1 TOTAL SNOWFALL FOR THE MONTH................8.9 DEPARTURE......+1.9 TOTAL SNOWFALL FOR THE SEASON..............22.8 DEPARTURE.....-29.6 PRELIMINARY CLIMATE SUMMARY FOR MARCH 2007......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 3/1 40/22/31/-1/0/0/512/76 24 NW Aero 23 MPH NW 3/2 49/28/39/+7/1.74/0.4/000/00 48 E Aero 45 MPH E 3/3 58/33/46/+14/0/0/489/72 44 WNW Aero 43 MPH WNW 3/4 40/26/33/0/0/0/471/69 37 W 3/5 37/19/28/-5/T/T/198/29 58 W Aero 57 MPH W 3/6 19/3/11/-22/0/0/667/97 * 57 W Aero 61 MPH W 3/7 22/2/12/-21/0/0/504/73 28 SW 3/8 25/5/15/-19/T/T/471/68 51 WNW Aero 54 MPH WNW 3/9 34/1/18/-16/0/0/668/96 * 25 S 3/10 49/22/36/+2/0/0/322/46 39 S Aero 39 MPH S 3/11 51/33/42/+7/0.26/0/513/73 32 W 3/12 55/31/43/+8/0/0/423/60 24 SSW 3/13 60/36/48/+13/0/0/319/45 35 S Aero 33 MPH S 3/14 66/42/54/+18/0/0/405/57 36 S 3/15 54/35/45/+9/0.07/0/000/00 36 NW 3/16 35/24/30/-6/1.65/8.5/000/00 55 NE Aero 53 MPH NE 3/17 morning low temp. 27 deg; normal now 28 deg. * Record low maximum temperature of 19 on the 6th surpasses previous 21 set in 1916. * Record low minimum temperature of 3 on the 6th ties previous 3 set in 1948. * Record low minimum temperature of 1 on the 9th breaks previous 5 set in 1885, 1943, and 1996. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MARCH 17 HIGH 69 IN 2003 LOW 6 IN 1885 PRECIP 1.97 INS. IN 1968 SNOWFALL 6.5 INS. IN 1956 PEAK GUST 70 MPH SSW IN 1973 RECORDS FOR MARCH 18 HIGH 68 IN 1999 LOW 0 IN 1885 PRECIP 5.61 INS. IN 1968 [RECORD FOR MONTH] SNOWFALL 9.3 INS. IN 1985 PEAK GUST 71e MPH WNW IN 1941 TODAY'S REPORT By: Mike Iacono If you do not wish to receive this Daily Discussion and Climate Summary from the Blue Hill Observatory, please send an email to sitemaster@bluehill.org.