BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY WEDNESDAY, APRIL 16, 2008 ALL TIMES ARE IN EASTERN STANDARD TIME UNLESS NOTED PERFECTLY CLEAR SKY AGAIN FOR A SECOND DAY SUNNY VERY DRY WEATHER CONTINUES WITH LIGHT WINDS TEMPERATURES RISING FROM 39 TO THE LOW 60'S It's quite rare to have a second consecutive day with not a cloud visible from the summit. Visibility is slowly decreasing from the 80 miles and more of the past two days but is still up to 60 to 70 miles today with slowly increasing distant light haze. The airmass continues very dry with dewpoints not far from 20 degrees and about where they were yesterday. Once again, for a second straight day, the relative humidity has dropped to near 20%. Temperatures are running several degrees warmer reaching the lower 60's early this afternoon after a high of 57 degrees yesterday. Today's observations: 8 A.M. EDT Weather: Clear Temperature: 46F, Dew point: 20F Wind: NW at 6 kts Sea-level pressure: 30.30 inches Hg, rising Visibility: 70 miles 6-hour min temp: 39F 24-hour precipitation: none BHO SA 1155 CLR 70 259/46/20/3206/030/ THN K LYR BLO SHLW DSSPTG INVSN NE HRZN/ 52023 10046 20039 11 A.M. EDT Weather: Clear Temperature: 56F, Dew point: 20F, Wind: WNW at 5 kts Sea-level pressure: 30.31 inches Hg, rising Visibility: 65 miles, NW 70 miles, distant light haze BHO SA 1455 CLR 65 267/56/20/2905/032/ VSBY NW 70 DSNT LGT HZ/ 51008 2 P.M. EDT Weather: Clear Temperature: 61F, Dew point: 19F, Wind: E at 6 kts Wind: Light and variable Sea-level pressure: 30.28 inches Hg, falling Visibility: 65 miles, 70 miles NW, distant light haze 6-hourly max.temp: 62F BHO SA 1755 CLR 65 253/61/19/0806/028/ DSNT LGT HZ WND L/V/ 58014 10062 20046 WEATHER SUMMARY FOR TUESDAY, APRIL 15 TEMPERATURE (DEGREES F) MAX.....57 NORMAL.....55 MIN.....33 NORMAL.....37 MEAN....45 NORMAL.....46 DEPARTURE FROM 30-YEAR NORMAL..........- 1 TOTAL DEPARTURE FOR THE MONTH..........+12 [+0.6 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............20 DEPARTURE....... +1 TOTAL HEATING UNITS FOR THE MONTH...........308 DEPARTURE.......-12 TOTAL HEATING UNITS FOR THE SEASON.........5445 DEPARTURE......-339 TOTAL HEATING UNITS LAST SEASON TO DATE....5407 DIFFERENCE......+38 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............23 SSE AT 6:17 P.M.* AEROVANE.............23 SSE AT 6:27 P.M. ASOS.................22 SSE AT 6:27 P.M. DAVIS................24 SSE AT 6:27 P.M. FASTEST MILE FOR YESTERDAY............. 17 SSE AT 6:27 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........16 SSE AT 7:18 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........18 SSE AT 6:18 P.M. AVERAGE WIND SPEED AND DIRECTION...... 9.1 NW ASOS................9.2 DAVIS...............9.7 WNW [290 deg] * Last of several occurrences. 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..........1.52 DEPARTURE......-0.73 ASOS..............1.66 TOTAL PRECIPITATION FOR THE YEAR..........19.12 DEPARTURE......+3.24 ASOS.............21.54 # Includes erroneous ASOS precipitation data on 2/13/08. SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M.........0.0 DEPARTURE......-0.1 TOTAL SNOWFALL FOR APRIL...................0.0 DEPARTURE......-1.6 TOTAL SNOWFALL FOR THE SEASON.............66.5 DEPARTURE......+7.9 PRELIMINARY CLIMATE SUMMARY FOR APRIL 2008 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available, records not finalized 4/1 59/50/55/+14/0.20/0/000/00 54 S Aero 58 MPH SSW 4/2 47/31/39/-3/0/0/745/97 52 W Aero 51 MPH W 4/3 52/27/40/-2/0/0/648/84 37 SSW 4/4 43/34/39/-3/0.71/0/000/00 35 E 4/5 51/37/44/+1/0.06/0/093/12 21 W 4/6 40/36/38/-5/0.09/0/000/00 36 NE 4/7 39/34/37/-6/0/0/172/22 35 NE Aero 36 MPH NE 4/8 47/30/39/-5/0/0/627/80 22 NE 4/9 59/33/47/+3/0/0/150/19 29 S 4/10 71/44/58/+14/T/0/624/79 34 W 4/11 54/40/47/+2/0.03/096/13 24 SE 4/12 70/43/57/+12/0.43/0/342/43 40 WNW Aero 42 WNW 4/13 47/34/41/-4/T/0/104/13 30 NW 4/14 53/30/42/-4/0/0/625/78 29 NW 4/15 57/33/45/-1/0/0/803/100 23 SSE 4/16 morning low temp. 39F; our normal low is now 37F NEW DAILY RECORDS FOR APRIL 2008 None to date. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 16 HIGH 87 IN 1896 LOW 23 IN 1943 PRECIP 2.45 IN. IN 1929 SNOWFALL 2.0 IN. IN 1904, 1962 PEAK GUST 73 MPH E IN 2007 RECORDS FOR APRIL 17 HIGH 93 IN 2002 LOW 21 IN 1908 PRECIP 1.68 IN 1954 SNOWFALL 1.0 IN. IN 1899 PEAK GUST 58 MPH NW IN 1994 TODAY'S REPORT PREPARED By: Robert Skilling