BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, APRIL 18, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME WARMEST TEMPERATURE OF THE YEAR SO FAR ON FRIDAY... The high temperature of 69 on Friday was the highest recorded so far this year. Sunshine early this morning has been replaced with clouds by mid-morning, and some virga was observed in the area at 11 AM EDT. Although showers are possible later today, it remains very dry with dew points in the upper 20s and the relative humidity near or below 30 percent. April continues to be slightly warmer and wetter than average. Today's weather observations: 7 A.M. Weather: Scattered altocumulus, thin overcast cirrus, few cirrocumulus overhead Temperature: 54F, Dew point: 29F, Wind: W at 8 kts Sea-level pressure: 29.93 inches Hg, rising Visibility: 45 miles, hazy 6-hour minimum temperature: 50F BHO SA 1155 110 SCT 200 –OVC 45 137/54/29/2808/993/ FEW CC OVHD HAZY WND LGT/ 8/071 51003 10054 20050 10 A.M. Weather: Broken stratocumulus, overcast altocumulus, virga NW and ENE Temperature: 59F, Dew point: 28F, Wind: NW at 10 kts, Wind: Direction variable W to NNW Sea-level pressure: 29.92 inches Hg, falling Visibility: 55 miles BHO SA 1455 E70 BKN 100 OVC 55 134/59/28/3110/992/ VIRGA NW AND ENE WND 28V34/ 8/57/ 55003 1 P.M. Weather: Scattered stratocumulus, broken altocumulus, broken cirrus Temperature: 62F, Dew point: 30F, Wind: NW at 7 kts Sea-level pressure: 29.91 inches Hg, falling Visibility: 40 miles 6-hourly max. temp: 64F BHO SA 1755 E65 SCT 100 BKN 200 BKN 40 131/62/30/3207/ 991/ WND LGT AND VRB/ 8/571 58003 10064 20054 WEATHER SUMMARY FOR FRIDAY, APRIL 17, 2009 TEMPERATURE (DEGREES F) MAX.....69 NORMAL......56 MIN.....35 NORMAL......38 MEAN....52 NORMAL......47 DEPARTURE FROM 30-YEAR NORMAL..................+5 TOTAL DEPARTURE FOR THE MONTH.................+10 [+0.4 DEGREE/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............13 DEPARTURE........-5 TOTAL HEATING UNITS FOR THE MONTH............347 DEPARTURE.......-10 TOTAL HEATING UNITS FOR THE SEASON..........5765 DEPARTURE.......-56 TOTAL HEATING UNITS LAST SEASON TO DATE.....5470 DIFFERENCE.....+295 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............37 W AT 5:37 P.M. AEROVANE.............33 W AT 5:37 P.M. * ASOS.................35 W AT 5:36 P.M. DAVIS................37 W AT 3:55 P.M. FASTEST MILE FOR YESTERDAY..............26 W AT 5:47 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........23 WNW AT 5:48 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........26 W AT 5:47 P.M. AVERAGE............14.0 W ASOS...............12.7 DAVIS..............13.3 W [259 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...........3.23 DEPARTURE.........+0.69 ASOS...............3.28 TOTAL PRECIPITATION FOR THE YEAR...........13.31 DEPARTURE.........-2.86 ASOS..............14.41 # # Includes erroneous ASOS precipitation data on 1/1/09, 1/2/09 and 2/27/09. 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.........-1.6 * TOTAL SNOWFALL FOR THE SEASON..............78.9 DEPARTURE........+20.2 * Monthly snowfall departure corrected from value in yesterday's report. 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 AER0 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/.../.. 35 NE AERO 31 MPH NE 4/16 50/34/42/-4/0/0/.../.. 29 NNE 4/17 69/35/52/+5/0/0/.../.. 37 W AERO 33 MPH W 4/18 morning low temp: 50F; our normal low is now 38F NEW DAILY RECORDS FOR APRIL 2009... None to date.. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 18 HIGH 92 IN 1976 LOW 23 1887 PRECIP 1.48 IN 1954 SNOWFALL 3.7 IN. IN 1965 PEAK GUST 59 MPH S IN 1982 RECORDS FOR APRIL 19 HIGH 94 IN 1976 [RECORD FOR MONTH] LOW 21 IN 1890 PRECIP 1.71 IN 1969 SNOWFALL 6.0 IN. IN 1887 PEAK GUST 66 MPH E IN 1984 TODAY'S REPORT PREPARED BY: Mike Iacono