BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, APRIL 21, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME SPECTACULAR SPRING WEATHER TODAY...HIGH TEMPERATURE REACHES MID-70S FOR THE FIRST TIME THIS YEAR...APRIL NOW 8TH WETTEST ON RECORD... Under full bright sunshine today with high thin clouds decorating the sky, the temperature has soared to a high of 74 deg F by early afternoon. This is the highest temperature so far this year. The air is also very dry with a dew point of 20 and relative humidity of 13% being measured at 2 PM EDT. Visibility is very high today averaging 70-75 miles. The wind direction has veered from W this morning to NNE by 3 PM EDT as a sea breeze is setting up along the coast this afternoon. The monthly rainfall of 7.18 inches already ranks April as the 8th wettest on our 122-year precipitation record through the 20th. Wettest Aprils (inches) 1) 10.37 in 1987 2) 9.38 in 2004 3) 8.71 in 1929 4) 8.53 in 1904 5) 7.57 in 1935 7.57 in 1983 7) 7.31 in 1901 8) 7.18 in 2007 (through 20th) 9) 7.04 in 1933 10) 6.94 in 1958 Today's observations: 7 A.M. Weather: High thin scattered cirrus Temperature: 55F, Dew point: 23F, Wind: NW at 10 kts Sea-level pressure: 30.09 ins. Hg, rising Visibility: 70 miles 6-hour min. 45 deg. BHO SA 1155 250 –SCT 70 190/55/23/3010/009/ FEW HIR CI/ 8/001 51014 10055 20045 10 A.M. Weather: Thin broken cirrus Temperature: 68F, Dew point: 24F, Wind: W at 6 kts Sea-level pressure: 30.08 inches Hg, falling Visibility: 70 miles BHO SA 1455 200 SCT 250 –BKN 70 187/68/24/2806/008/ FEW CC OVHD WND LGT AND VRB/ 8/001 58003 1 P.M. Weather: Thin broken cirrus Temperature: 74F, Dew point: 20F, Wind: NW at 12G21 kts Sea-level pressure: 30.04 inches Hg, falling Visibility: 75 miles BHO SA 1755 250 –BKN 75 173/74/20/3112G21/004/ FEW LWR CI/ 8/001 56014 10074 20055 WEATHER SUMMARY FOR FRIDAY, APRIL 20 TEMPERATURE (DEGREES F) MAX.....57 NORMAL.....57 MIN.....36 NORMAL.....39 MEAN....47 NORMAL.....48 DEPARTURE FROM 30-YEAR NORMAL...........-1 TOTAL DEPARTURE FOR THE MONTH.........-117 (-6.1 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..........18 DEPARTURE.........+1 TOTAL HEATING UNITS FOR THE MONTH.........526 DEPARTURE.......+116 TOTAL HEATING UNITS FOR THE SEASON.......5520 DEPARTURE.......-354 TOTAL HEATING UNITS LAST SEASON TO DATE..5242 DIFFERENCE......+278 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............31 N AT 6:17 A.M. AEROVANE.............28 N AT 6:57 A.M. ASOS.................26 N AT 6:52 A.M. DAVIS................29 N AT 6:16 A.M. FASTEST MILE FOR YESTERDAY..............19 N AT 6:53 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE...........21 N AT 6:53 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........22 N AT 6:52 A.M. AVERAGE WIND SPEED AND DIRECTION........12.0 NNE ASOS................12.1 DAVIS...............11.5 NE [037 deg] * last of several occurrences PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE.....-0.14 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........7.18 DEPARTURE.....+4.22 ASOS..............6.85 TOTAL PRECIPITATION FOR THE YEAR..........18.92 DEPARTURE.....+2.33 ASOS.............18.49 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......-1.9 TOTAL SNOWFALL FOR THE SEASON..............27.6 DEPARTURE.....-31.4 PRELIMINARY CLIMATE SUMMARY FOR APRIL 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 4/1 59/33/46/+5/0.42/0/511/67 30 S 4/2 39/35/37/-5/0.33/0/000/00 27 E 4/3 41/32/37/-5/0.04/0/000/00 28 ENE 4/4 36/32/34/-8/0.90/0.2/000/00 38 E 4/5 43/26/35/-8/0.21/T/163/21 36 WSW 4/6 39/23/31/-12/0/0/590/76 36 WSW 4/7 40/26/33/-10/0/0/405/52 35 W 4/8 40/25/33/-11/0/0/619/79 44 W Aero 42 MPH W 4/9 50/30/40/-4/0/0/746/95 36 W 4/10 43/30/37/-7/0/0/158/20 28 W 4/11 51/28/40/-5/0/0/712/90 22 SSE 4/12 39/32/36/-9/0.89/T/000/00 42 E Aero 40 MPH E 4/13 47/31/39/-6/0/0/096/12 41 W Aero 42 MPH W 4/14 52/35/44/-2/0/0/392/49 37 W 4/15 44/35/40/-6/1.75/T/000/00 66 E Aero 64 MPH E 4/16 50/40/45/-1/1.56/0/000/00 73 E Aero 73 MPH E 4/17 40/35/38/-9/0.69/T/000/00 54 NNE 4/18 39/36/38/-9/0.37/0/000/00 43 N 4/19 49/36/43/-4/0.02/T/285/35 38 NE Aero 35 MPH NE 4/20 57/36/47/-1/0/0/.../.. 31 N 4/21 morning low temp. 45 deg; normal low now 39 deg. NEW DAILY RECORDS FOR APRIL SO FAR.... 4/15 - NEW RECORD HIGH PEAK WIND GUST FOR THIS DATE OF 66 MPH E; the previous record was 59 mph estimated from the S in 1946 and measured from the S in 1980. NEW RECORD DAILY RAINFALL OF 1.75 INS.; previous record 1.29 ins. in 1990. 4/16 - NEW RECORD HIGH PEAK WIND GUST OF 73 MPH E; the previous record for this date was 63 mph SSE in 1996. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 21 HIGH 85 IN 1923 LOW 22 IN 1908 PRECIP 3.18 IN. IN 1991 SNOWFALL 0.8 IN. IN 1947 PEAK GUST 76e MPH NE IN 1940 RECORDS FOR APRIL 22 HIGH 85 IN 1977, 2001 LOW 26 IN 1981 PRECIP 1.85 IN. IN 2000 SNOWFALL 3.0 IN. IN 1940 PEAK GUST 68e MPH NW IN 1945 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.