BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, APRIL 30, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME Today's observations: 7 A.M. Weather: Thin broken cirrus Temperature: 49F, Dew point: 24F, Wind: SW at 7 kts Sea-level pressure: 30.47 inches Hg, rising Visibility: 35 miles, 50 miles NW, light haze 6-hour min temp: 41F BHO SA 1155 300 –BKN 35 318/49/24/2307/047/ THN K LYR N-NE AND SE-SW VSBY NW 50 LGT HZ/ 8/001 53006 10049 20041 10 A.M. Weather: Thin overcast cirrus, few altocumulus SW-W, partial halo Temperature: 63F, Dew point: 26F, Wind: S at 11 kts, Wind: Direction variability SE to W Sea-level pressure: 30.44 inches Hg, falling Visibility: 35 miles, 55 miles northwest, light haze BHO SA 1455 250 –BKN 300 –OVC 35 309/63/26/1711/044/ FEW AC SW-W PARTIAL HALO VSBY NW 55 LGT HZ WND 14V26/ 8/031 58009 1 P.M. Weather: Broken cirrostratus, overcast cirrus, few stratocumulus distant S-SW, few altocumulus lenticularis W-N, partial halo Temperature: 65F, Dew point: 22F, Wind: S at 16G24 kts Wind: Direction variability SE to SW Sea-level pressure: 30.38 inches Hg, falling Visibility: 55 miles, light haze 6-hourly max. temp: 67F BHO SA 1755 E220 BKN 250 OVC 55 287/65/22/1816G24/038/ FEW SC DSNT S-SW AC/ACSL W-N PARTIAL HALO LGT HZ WND 13V23/ 8/547 58022 10067 20049 WEATHER SUMMARY FOR WEDNESDAY, APRIL 29 TEMPERATURE (DEGREES F) MAX.....63 NORMAL.....61 MIN.....44 NORMAL.....41 MEAN....54 NORMAL.....51 DEPARTURE FROM 30-YEAR NORMAL...........+3 TOTAL DEPARTURE FOR THE MONTH..........+99 [+3.2 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............11 DEPARTURE.......-3 TOTAL HEATING UNITS FOR THE MONTH...........467 DEPARTURE......-81 TOTAL HEATING UNITS FOR THE SEASON.........5885 DEPARTURE.....-127 TOTAL HEATING UNITS LAST SEASON TO DATE....5591 DIFFERENCE....+294 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............35 NW AT 12:09 A.M. AEROVANE.............30 NW AT 12:09 A.M. ASOS.................32 NNW AT 12:10 A.M. DAVIS................34 W AT TIME N/A FASTEST MILE FOR YESTERDAY..............22 NW AT 12:14 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........21 NW AT 12:11 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........22 NW AT TIME N/A AVERAGE WIND SPEED AND DIRECTION......10.9 NW ASOS...............10.1 DAVIS..............10.7 NNW [345 DEG] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE....-0.13 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........4.53 DEPARTURE....+0.34 ASOS..............4.55 TOTAL PRECIPITATION FOR THE YEAR..........14.61 DEPARTURE....-3.21 ASOS.............15.68 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.....-0.1 TOTAL SNOWFALL FOR THE MONTH................0.2 DEPARTURE.....-2.8 TOTAL SNOWFALL FOR THE SEASON..............78.9 DEPARTURE.....19.0 PRELIMINARY CLIMATE SUMMARY FOR APRIL 2009 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system gust when significant TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 4/1 43/31/38/-3/0.13/0/015/02 24 SE 4/2 52/39/46/+4/0.02/0/000/00 20 SSE 4/3 58/45/52/+10/0.70//000/00 39 SSE AERO 38 MPH SSE TSTM 4/4 51/38/45/+3/0.01/0/015/02 48 WSW AERO 48 MPH WSW 4/5 58/37/48/+5/0/0/551/71 40 W AERO 37 MPH W 4/6 55/38/47/+4/1.42/0/047/006 42 SE AERO 40 MPH SE TSTM 4/7 50/34/42/-1/T/0/109/14 36 WSW AERO 35 MPH WSW 4/8 45/32/39/-5/0/0/149/19 33 SW AERO 31 MPH SW 4/9 60/34/47/+3/0/0/692/88 36 SSW AERO 33 MPH SSW 4/10 65/41/53/+9/0.18/0/544/69 37 SSW AERO 35 MPH SSW 4/11 44/33/39/-6/0.77/0.2/000/00 35 N AERO 30 MPH N 4/12 43/29/36/-9/0/0/541/68 45 NW AERO 43 MPH WNW 4/13 52/29/41/-4/0/0/734/92 38 W AERO 35 MPH W 4/14 58/37/48/+2/0/0/696/87 25 E 4/15 49/36/43/-3/0/0/650/81 35 NE AERO 31 MPH NE 4/16 50/34/42/-4/0/0/806/100 29 NNE 4/17 69/35/52/+5/0/0/695/86 37 W AERO 33 MPH W 4/18 64/44/54/+7/0.05/0/170/21 28 W 4/19 52/38/45/-2/0.03/0/773/95 33 NNE AERO 28 MPH NNE 4/20 51/36/44/-4/0.10/0/.../... 43 E AERO 39 MPH E 4/21 58/42/50/+2/0.95/0/000/00 43 E AERO 43 MPH S 4/22 62/45/54/+5/0.16/0/.../.. 28 S 4/23 56/40/48/-1/0.01/0/.../.. 43 W 4/24 70/40/55/+6/0/0/.../.. 30 W 4/25 83/49/66/+16/T/0/.../.. 29 S 4/26 88/56/72/+22/0/0/.../.. 33 NE 4/27 72/49/61/+11/0/0/.../.. 4/28 92/57/75/+24/0/0/.../.. 37 SSW AERO 36 MPH S 4/29 63/44/54/+3/T/0/.../.. 35 NW AERO 30 MPH NW TSTM 4/30 morning low temperature 41F; our normal low is now 42F NEW DAILY RECORDS FOR APRIL 2009... New record high maximum temperature for April 25 of 83F surpasses 80F in 1942. New record high maximum temperature for April 26 of 88F surpasses 83F in 1908. New record high minimum temperature for April 26 of 56F surpasses 55F in 1985. Maximum temperature of 92F for April 28 equals record high maximum of 92F in 1990. Minimum temperature of 57F for April 28 equals record high minimum of 57F in 1935. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 30 HIGH 86 IN 1942 LOW 30 IN 1931 PRECIP 1.41 IN 1991 SNOWFALL 0.3 IN. IN 1909 PEAK GUST 64e MPH NW IN 1978 RECORDS FOR MAY 1 HIGH 87F IN 1899 LOW 29F IN 1978 PRECIP 2.53 INCHES IN 1921 SNOWFALL TRACE IN 1905,1917,1921,1995. PEAK GUST 57 MPH NW IN 1974 TODAY'S REPORT PREPARED BY: Stephanie Radner