BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, MAY 10, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME 0.83 INCH OF MUCH NEEDED RAIN FELL OVER THE PAST 2 DAYS; FOGGY START GIVES WAY TO WARM, MUGGY AFTERNOON WITH SOME SUNSHINE A few rain and thunder showers provided additional much needed rainfall on Thursday. The 2-day rainfall total has now reached 0.83 inch. The summit began the morning shrouded in fog, reducing visibility to near zero at times. The fog quickly dissipated shortly after 8 AM EDT, giving way to a sunny sky. A few cumulus have developed this afternoon, and high thin cirrus clouds have been streaming in throughout the day ahead of an approaching storm system. The sunshine and general S-W flow has pushed temperatures into the mid 70s for the second time this week. For the day, temperatures are averaging about 10 degrees above the 30 year normal. Winds continue to be quite calm. Thursday's winds averaged only 4.8 mph. The wind has been completely calm at times today, and the day will likely end up averaging similar to yesterday's low wind speeds. Today's observations: 7 A.M. Weather: Sky partially obscured by dense fog, stratus drifting over, summit, clear sky overhead, sun visible Temperature: 56F; Dew Point: 56F; Wind: SW at 4 kts. Sea-level pressure: 29.96 ins. Hg, rising Visibility: 1/8 mile, variable 1/16 to 1/4 mile, increasing 24-hour precip: 0.39 inch 6-hour min. temp: 54F BHO SA 1155 –X 1/8VF 147/56/56/2304/996/ F4 STRA DRFTNG OVR SMT CLR SKY OVHD SUN VSBL VSBY 1/16V1/4 VSBY INCRSNG/ 8/600 51014 ASOS 70038 MANUAL 70039 10056 20054 10 A.M. Weather: Scattered cumulus, scattered thin cirrus, small cumulus forming all quadrants, thin line of moderate cumulus distant NW-N, stratus layer over ocean distant NE-ENE, cirrus SSW-W-N invading the sky, distant haze Temperature: 69F; Dew Point: 57F; Wind: Estimated SW at 3 kts, Wind: Light and variable Sea-level pressure: 29.98 ins. Hg, rising slightly Visibility: 50 miles, distant haze BHO SA 1455 20 SCT 250 –SCT 50 151/69/57/E2303/998/ SML CU FRMG ALQDS THN LINE MDT CU DSNT NW-N STRA LYR OVR OCN DSNT NE-ENE CI SSW-W-N INVADING DSNT HZ WND LGT AND VRB/ 8/204 51004 1 P.M. Weather: Scattered cumulus, scattered dense cirrus, broken thin cirrus, few moderate cumulus all quadrants except NE-E, fog/stratus layer over ocean distant NNE-E, patches of dense cirrus SSW-NW and N, thin smoke layer aloft distant N-ESE, distant haze Temperature: 75F; Dew Point: 54F; Wind: Estimated S at 2 kts, Wind: Light and variable Sea-level pressure: 29.96 ins. Hg, falling slightly Visibility: 50 miles, WNW 55 miles, N-E lower due to fog/stratus layer, distant haze 6-hour max. temp: 76F BHO SA 1755 40 SCT 220 SCT 250 –BKN 50 146/75/54/E1802/996/ FEW MDT CU ALQDS XCPT NE-E FG/STRA LYR OVR OCN DSNT NNE-E PTCHS DNS CI SSW-NW AND N THN K LYR ALF DSNT N-ESE DSNT HZ VSBY WNW 55 N-E LWR WND LGT AND VRB/ 8/202 58006 10076 20056 WEATHER SUMMARY FOR THURSDAY, MAY 9, 2013 TEMPERATURE (DEGREES F) MAX.....66 NORMAL.....64 MIN.....56 NORMAL.....46 MEAN....61 NORMAL.....55 DEPARTURE FROM 30-YEAR NORMAL....................+6 TOTAL DEPARTURE FOR THE MONTH...................+14 [+1.4 DEGREE/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............4 DEPARTURE..........-6 TOTAL HEATING UNITS FOR THE MONTH............85 DEPARTURE.........-18 TOTAL HEATING UNITS FOR THE SEASON.........5607 DEPARTURE........-531 TOTAL HEATING UNITS LAST SEASON TO DATE....4834 DIFFERENCE.......+773 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............16 NE AT 3:28 P.M. AERO....................16 NE AT 3:28 P.M. * ASOS....................18 NE AT 3:29 P.M. DAVIS...................17 NE AT 3:27 P.M. RMY: 18 THE FASTEST MILE FOR YESTERDAY.............12 ENE AT 6:49 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE..............13 ENE AT 6:53 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............12 NE AT 3:30 P.M. AVERAGE WIND SPEED AND DIRECTION..........4.8 NE ASOS...................3.5 DAVIS..................4.5 ENE [074 deg] *Last of several occurrences. PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.39 DEPARTURE...........+0.28 ASOS..............0.38 TOTAL PRECIPITATION FOR THE MONTH..........0.83 DEPARTURE...........-0.27 ASOS..............0.80 TOTAL PRECIPITATION FOR THE YEAR..........17.21 DEPARTURE...........-2.44 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/.../.. 17 S AERO 18 MPH S RMY 20 5/7 77/50/64/+9/0.00/.../.. 21 S AERO 23 MPH S RMY 25 5/8 71/55/63/+8/0.42/.../.. 31 SSE AERO 35 MPH SSE RMY 35 TSTM 5/9 66/56/61/+6/0.41/.../.. 16 NE AERO 16 MPH NE RMY 18 TSTM 5/10 morning low temp: 54F; the normal low is now 46F 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 10 HIGH 93F IN 1896 LOW 29F IN 1900 PRE 1.85 INS IN 1998 SNOW 2.8 INS 1977 (7.8 INS TOTAL 5/9-5/10 1977) PEAK GUST 64 MPH S IN 1990 RECORDS FOR MAY 11 HIGH 90F IN 1993 LOW 28F IN 1900 PRE 1.28 INS IN 1957 SNOW 1.0 INS IN 1907 (LATEST MEASURABLE SNOW ON RECORD) PEAK GUST 75e MPH NW IN 1945 TODAY'S REPORT PREPARED BY: Sean Fankhauser