BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 25, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME ANOTHER OVERCAST, FOGGY DAY WITH LIGHT RAIN Once again, clouds, fog, and light rain have made for a gloomy day at the summit today. A total of 0.63 inches of rain fell between 7AM yesterday and 7AM this morning, which helped to further decrease our precipitation deficit for the month. Light showers, mist, and drizzle, which have been almost continuous today, have added another 0.10 inches so far. Temperatures have been running below average, with a morning low of 47F and a high temperature so far of only 50F. Winds have been fairly light and mostly out of the N-NW. The fog has kept the sky at least partially obscured for much of the day, which has generally held the visibility to 3 miles or less. Today's observations: 7 A.M. Weather: Sky partially obscured by light rain and fog, overcast nimbostratus, stratus fractus drifting above and below summit Temperature: 48F; Dew Point: 47F; Wind: N at 10G18 kts, Wind: Direction variable NW-NNE Sea-level pressure: 29.76 ins. Hg, rising then falling Visibility: 1/2 mile, light rain and fog 6-hr min. temp: 47F 24-hr precip: 0.63 inch BHO SA 1155 –X E3 OVC 1/2R-F 079/48/47/3510G18/976/ F3 STFRA DRFTNG OVR AND BLO SMT WND 32V03/ 50003 ASOS 60028 MANUAL 70063 ASOS 70061 8/7// 10048 20047 10 A.M. Weather: Sky partially obscured by light rain and fog, overcast nimbostratus Temperature: 49F; Dew Point: 48F; Wind: NNW at 9 kts Sea-level pressure: 29.73 ins. Hg, falling then falling more rapidly Visibility: 1 miles, 3 miles SSE-SSW, light rain and fog 3-hourly precip: 0.05 inch BHO SA 1455–X E7 OVC 1R-F 068/49/48/3309/973/ F2 VSBY 3 SSE-SSW/ 8/02/ 58011 MANUAL 60005 ASOS 60005 1 P.M. Weather: Sky partially obscured by light rain and fog, overcast nimbostratus, stratus fractus drifting over and below summit SW-NW Temperature: 49F; Dew Point: 49F; Wind: NW at 9 kts Sea-level pressure: 29.72 ins. Hg, falling then falling more rapidly Visibility: 2 miles, light rain and fog 6-hour max temp: 50F 6-hour precip: 0.10 in. BHO SA 1755 –X E7 OVC 2R-F 065/49/49/3209/972/ F3 STFRA DRFTNG OVR AND BLO SMT SW-NW/ 8/7// 58003 MANUAL 60010 ASOS 60009 10050 20047 WEATHER SUMMARY FOR FRIDAY, MAY 24, 2013 TEMPERATURE (DEGREES F) MAX.....68 NORMAL.....69 MIN.....49 NORMAL.....50 MEAN....58 NORMAL.....59 DEPARTURE FROM 30-YEAR NORMAL....................-1 TOTAL DEPARTURE FOR THE MONTH...................+53 [+2.0 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............7 DEPARTURE..........+1 TOTAL HEATING UNITS FOR THE MONTH...........166 DEPARTURE.........-62 TOTAL HEATING UNITS FOR THE SEASON.........5688 DEPARTURE........-574 TOTAL HEATING UNITS LAST SEASON TO DATE....4888 DIFFERENCE.......+800 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............33 S AT 12:17 A.M. AERO....................35 S AT 12:19 A.M. * ASOS....................36 S AT 12:18 A.M. DAVIS...................35 S AT 12:19 A.M. RMY: N/A FASTEST MILE FOR YESTERDAY.................27 S AT 12:19 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE..............25 S AT 12:19 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............N/A AVERAGE WIND SPEED AND DIRECTION.......... 12.3 S ASOS....................11.5 DAVIS...................11.3 SSW [210 deg] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.63 DEPARTURE...........+0.48 ASOS..............0.61 TOTAL PRECIPITATION FOR THE MONTH..........2.20 DEPARTURE...........-0.85 TOTAL ASOS PRECIPITATION FOR MONTH.........2.13 TOTAL PRECIPITATION FOR THE YEAR..........18.58 DEPARTURE...........-3.02 ASOS..............N/A* *ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals 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.............0.0 TOTAL SNOWFALL FOR THE SEASON.............99.0 DEPARTURE...........+36.3 PRELIMINARY CLIMATE SUMMARY FOR MAY 2013 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane wind recording system gust 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 67/45/56/+3/0.00/845/100 18 E AERO 16 MPH E RMY 17 5/2 75/43/59/+6/T/669/79 29 NE AERO 26 MPH NE RMY 29 5/3 54/42/48/-5/0.00/706/83 24 NE AERO 25 MPH NE RMY 28 5/4 55/40/48/-6/0.00/843/99 21 NE AERO 23 MPH NE RMY 23 5/5 58/37/48/-6/0.00/752/88 17 ENE AERO 17 MPH ENE RMY 20 5/6 66/40/53/-1/0.00/600/70 17 S AERO 18 MPH S RMY 20 5/7 77/50/64/+9/0.00/807/94 21 S AERO 23 MPH S RMY 25 5/8 71/55/63/+8/0.42/112/13 31 SSE AERO 35 MPH SSE RMY 35 TSTM 5/9 66/56/61/+6/0.41/078/09 16 NE AERO 16 MPH NE RMY 18 TSTM 5/10 79/54/67/+12/T/333/63 18 S AERO 21 MPH S RMY N/A 5/11 70/56/63/+7/0.06/026/03 43 SSW AERO 44 MPH SSW RMY 46 5/12 71/47/59/+3/0.05/339/39 30 W AERO 32 MPH W RMY 32 5/13 60/41/51/-5/0.00/821/94 25 WSW AERO 28 MPH WSW RMY 30 5/14 58/38/48/-9/T/385/44 22 W AERO 24 MPH W RMY 25 5/15 65/41/53/-4/0.02/456/52 35 S AERO 38 MPH S RMY 40 5/16 80/51/66/+9/0.00/844/96 40 W AERO 45 MPH W RMY 42 5/17 69/50/60/+3/0.00/872/99 24 NW AERO 28 MPH NW RMY 27 5/18 73/47/60/+2/0.00/689/78 21 SE AERO 24 MPH SE RMY 24 5/19 71/50/61/+3/0.11/407/46 21 S AERO 23 MPH S RMY 24 5/20 81/54/68/+10/0.01/496/56 21 S AERO 21 MPH S RMY N/A 5/21 81/49/65/+6/0.14/506/57 29 NE AERO 31 MPH NE RMY 32 TSTM 5/22 66/48/57/-3/0.04/.../.. 27 WNW AERO 25 MPH WNW RMY N/A 5/23 74/53/64/+5/..../.../.. 35 S AERO 39 MPH S RMY 40 5/24 68/49/58/-1/..../.../.. 33 S AERO 35 MPH S RMY N/A 5/25 morning low temp: 47F; the normal low is now 51F DAILY RECORDS FOR MAY 2013 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 25 HIGH 91F IN 2007 LOW 37F IN 1967 PRECIP 3.73 INS IN 1967 PEAK GUST 83 MPH NE IN 1967 (RECORD FOR MAY) RECORDS FOR MAY 26 HIGH 94F IN 2010 (RECORD FOR MAY) LOW 37F IN 1972 PRECIP 1.73 INS IN 2003 SNOWFALL TRACE IN 1967 (Fell as ice pellets in nor'easter) PEAK GUST 62 MPH NE IN 1967 TODAY'S REPORT PREPARED BY: Jonathan O'Brien