BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 5, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME MORNING RAIN SHOWERS BRING 0.04 INCH OF RAINFALL... FOGGY, COOL WITH LOW WINDS THIS MORNING... NO SUNSHINE AGAIN SO FAR TODAY... Rain showers early this morning that occurred between 2-4 AM EDT brought a total of 0.04 inch of precipitation to the summit. Fog was reducing visibility to 1/4 mile during the first morning observation, through the fog slowly lifted later in the morning. Low clouds are holding in as of early afternoon, though there may be some breaks and a little sunshine later. If there is no sun today, this will be the fifth consecutive day with no sunshine. The last stretch of five days or more with no sunshine occurred on May 12-16, 2006. A period of eight days with no sunshine was observed on October 8-15, 2005. The wind speed has been unusually low today with a total of only 31 miles of wind for the period from midnight through 1 PM EST for a mean of 2.4 mph over that time. The peak gust for the day so far is 9 mph NE at 1:14 PM EST. Today's observations: 7 A.M. Weather: Sky obscured in dense fog, visibility briefly 1/2 mile S-W Temperature: 50F, Dew point: 50F, Wind: Calm, Sea-level pressure: 29.98 inches Hg, rising Visibility: 1/4 mile, dense fog 24-hour precip: 0.04 inch 6-hour precip: 0.04 6-hour min. temp: 49F BHO SA 1155 W3 X 1/4F 153/50/50/0000/998/ VSBY BRFLY 1/2 S-W/ 8//// 51014 6004/ 70004 10050 20049 10 A.M. Weather: Sky partly obscured in fog, overcast stratus, stratus drifting over summit, visibility increasing Temperature: 53F, Dew Point: 53F; Wind: NW at 4 kts Sea-level pressure: 30.02 inches Hg, rising Visibility: 1 1/2 miles, increasing past hour, thin fog/haze all quadrants 3-hour precip: Trace BHO SA 1455 –X E2 OVC 11/2F 165/53/53/3204/002/ F3 STRA DRFTG OVR SMT VSBY INCR WND LGT/ 8/6// 52012 1 P.M. Weather: Broken stratus, overcast stratocumulus, few lower stratus fractus, thin fog all quadrants Temperature: 56F, Dew Point: 53F; Wind: NE at 5 kts Wind: Direction gradually veering Wind: Light and variable Sea-level pressure: 30.02 inches Hg, rising slightly Visibility: 12 miles, visibility north 10, east 15, SSE-SSE 8 miles 6-hour precip: none 6-hour max. temp: 56F BHO SA 1755 E15 BKN 30 OVC 12 166/56/53/0505/002/ THN FG ALQDS FEW LWR STFRA VSBY N 10 E 15 SSE-SSW 8 WND LGT AND VRB WND GRDLY VEERING/ 8/6// 52001 10056 20050 WEATHER SUMMARY FOR FRIDAY, MAY 4 TEMPERATURE (DEGREES F) MAX.....55 NORMAL.....63 MIN.....47 NORMAL.....44 MEAN....52 NORMAL.....54 DEPARTURE FROM 30-YEAR NORMAL.......................-2 TOTAL DEPARTURE FOR THE MONTH......................-21 [-5.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY..............13 DEPARTURE..........+1 TOTAL HEATING UNITS FOR THE MONTH..............68 DEPARTURE.........+17 TOTAL HEATING UNITS FOR THE SEASON...........4782 DEPARTURE.......-1295 TOTAL HEATING UNITS LAST SEASON TO DATE......5931 DIFFERENCE......-1149 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............21 SSW AT 10:46 A.M. * AERO..................25 SSW AT 5:58 A.M. ASOS..................24 S AT 5:48 A.M. DAVIS.................22 S AT 10:55 A.M. RMY 23 THE FASTEST MILE FOR YESTERDAY...........17 SSW AT 10:54 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............18 SSW AT 11:18 A.M. DAVIS MAXIMUM 2-MINUTE AVERAGE...........17 S AT 10:56 A.M. AVERAGE WIND SPEED AND DIRECTION........9.2 SSW ASOS.................8.8 DAVIS................8.4 S [188 deg.] * last of several occurrences.... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.04 DEPARTURE..........-0.08 ASOS..............0.04 TOTAL PRECIPITATION FOR THE MONTH..........0.83 DEPARTURE..........+0.34 ASOS..............0.81 TOTAL PRECIPITATION FOR THE YEAR..........10.44 DEPARTURE..........-8.60 ASOS.............10.54 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE...........0.0 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE..........-0.1 TOTAL SNOWFALL FOR THE SEASON..............24.2 DEPARTURE.........-35.9 PRELIMINARY CLIMATE SUMMARY FOR MAY 2012 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust when significant RMY: RMY = R.M. Young wind gust recording system added 8/9/2011 TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 5/1 47/42/45/-8/0.65/0.0/000/00 33 SE AERO 36 MPH SE RMY 37 5/2 50/43/47/-6/0.05/0.0/000/00 16 ENE AERO 16 MPH ENE RMY 17 5/3 51/44/48/-5/0.08/0.0/000/00 14 SSE AERO 16 MPH SSE RMY N/A 5/4 56/47/52/-2/.../0.0/000/00 21 SSW AERO 25 MPH SSW RMY 23 5/5 morning low temp: 49F; the normal low is now 45F DAILY RECORDS FOR MAY 2012 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 5 HIGH 92F IN 1949 LOW 30F IN 1891 PRECIP 2.74 INCHES IN 1922 SNOWFALL 3.0 INCHES IN 1917 PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976 RECORDS FOR MAY 6 HIGH 90F IN 1930 LOW 29F IN 1891 PRECIP 1.04 INCHES IN 1890 SNOWFALL TRACE IN 1917,1996 PEAK GUST 65 MPH SSE IN 1989 TODAY'S REPORT PREPARED BY: Mike Iacono/Peter Volpe