BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, APRIL 12, 2008 ALL TIMES ARE IN EASTERN STANDARD TIME UNLESS NOTED RAIN AND THUNDERSHOWERS EARLY THIS MORNING GIVE WAY TO WARM SUNSHINE AT MID-DAY...CLOUDS AND SHOWERS RETURNING THIS AFTERNOON... A thunderstorm occurred between 6:30 and 7:30 AM EDT this morning, with a quick downpour and a wind gust to 40 mph WNW at 6:33 AM EDT. Fog briefly lifted from the summit just after 8 AM EDT for about 15 minutes revealing a nearly full undercast of low lying fog around the summit. Once all the fog cleared, warm sunshine brought the temperature up to 70 at mid-day. Building cumulus and showers are returning early this afternoon, and there may be more showers later today. Today's observations: 8 A.M. EDT Weather: Partial obscuration, broken stratus and fog, with higher altocumulus visible, partial undercast, rain and thunderstorm ended past hour Temperature: 47F, Dew point: 47F Wind: SE at 10 kts Sea-level pressure: 29.55 inches Hg, falling rapidly Visibility: 6 miles, variable 1 to 10 miles 6-hour min temp: 44F 24-hour precipitation: 0.40 inch BHO SA 1155 –X E2 BKN 100 BKN 6VF 008/47/47/1310/955/ F6 FEW SC VSBY 1V10 VSBY INCR PARTIAL UNDERCAST ALQDS SUN OCNL DMLY VSB RE54 TEUKN PRESFR/ 8/63/ 58017 60/// 70040 10048 20044 11 A.M. EDT Weather: Overcast stratus with fog, sun dimly visible Temperature: 50F, Dew point: 49F, Wind: ESE at 4 kts Sea-level pressure: 29.55 inches Hg, rising then falling Visibility: 1 mile, variable 1/2 to 1 1/2 miles BHO SA 1455 –X E3 OVC 1VF 008/50/49/1204/955/ F7 VSBY 1/2V11/2 VSBY INCR SUN DMLY VSB/ 8/6// 50000 2 P.M. EDT Weather: Scattered cumulus and altocumulus Temperature: 68F, Dew point: 56F, Wind: SSE at E2 kts Wind: Light and variable Sea-level pressure: 29.47 inches Hg, falling Visibility: 35 miles, hazy 6-hourly max.temp: 69F BHO SA 1755 35 SCT 100 SCT 35 981/68/56/E1602/947/ FEW ACSL N CU BLDG ALQDS HAZY WND LGT AND VRB/ 8/270 56027 10069 20047 WEATHER SUMMARY FOR FRIDAY, APRIL 11 TEMPERATURE (DEGREES F) MAX.....54 NORMAL.....54 MIN.....40 NORMAL.....36 MEAN....47 NORMAL.....45 DEPARTURE FROM 30-YEAR NORMAL...........+2 TOTAL DEPARTURE FOR THE MONTH...........+9 [+0.6 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............18 DEPARTURE........-2 TOTAL HEATING UNITS FOR THE MONTH...........233 DEPARTURE........-9 TOTAL HEATING UNITS FOR THE SEASON.........5370 DEPARTURE......-336 TOTAL HEATING UNITS LAST SEASON TO DATE....5306 DIFFERENCE......+64 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............24 SE AT 7:25 P.M. * AEROVANE.............24 SE AT 7:25 P.M. * ASOS.................22 S AT 7:26 P.M. DAVIS................25 SE AT 7:09 P.M. FASTEST MILE FOR YESTERDAY............. 18 SE AT 7:10 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........16 SSE AT 7:12 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........20 SE AT 7:11 P.M. AVERAGE WIND SPEED AND DIRECTION........7.9 NW ASOS.................6.3 DAVIS................7.7 W [268 deg] * Last of several occurrences. PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.40 DEPARTURE......+0.25 ASOS..............0.42 TOTAL PRECIPITATION FOR THE MONTH..........1.46 DEPARTURE......-0.19 ASOS..............1.58 TOTAL PRECIPITATION FOR THE YEAR..........19.06 DEPARTURE......+3.78 ASOS.............21.46 # 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.....-1.2 TOTAL SNOWFALL FOR THE SEASON...............66.5 DEPARTURE.....+8.4 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/.../0/000/00 35 E 4/5 51/37/44/+1/.../0/000/00 21 W 4/6 40/36/38/-5/0.09/0/093/12 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/.../.. 29 S 4/10 71/44/58/+14/T/0/.../.. 34 W 4/11 54/40/47/+2/.../0/.../.. 24 SE 4/12 morning low temp. 44F; normal low is now 36F 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 12 HIGH 82 IN 1945 LOW 17 IN 1926 PRECIP 1.51 IN. IN 1993 SNOWFALL 12.0 IN. IN 1894 PEAK GUST 65e MPH W IN 1978 RECORDS FOR APRIL 13 HIGH 85 IN 1945 LOW 22 IN 1939 PRECIP 2.51 IN. IN 2004 SNOWFALL 6.8 IN. IN 1933 PEAK GUST 59 MPH SSW IN 1995 TODAY'S REPORT PREPARED By: Mike Iacono