BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 4, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME SUNNY AND CONTINUED COOL TODAY WITH A NORTHEAST WIND... The low temperature was 44F this morning before sunrise, and despite nearly full sunshine, the temperature has once again only climbed into the low 50s as of early afternoon. Friday was 5 degrees cooler than normal with a high of only 54F. The dew point has dropped into the middle 30s today, though the visibility has diminished from near 50 miles earlier to about 35 miles this afternoon with considerable haze, partly due to the increasing levels of tree pollen in the air. Very dry weather continues. From March 20 through today (46 days), Blue Hill has received only 2.44 inches of precipitation. That is only 33% of the 30-year normal of 7.30 inches for this time period. APRIL 2013 PRELIMINARY STATISTICS: (departures relative to 1981-2010 average) TEMPERATURE: Average Max Temp: 58.1F [+2.4F] Average Min Temp: 38.1F [+0.4F] Mean Temp: 48.1F [+1.4F] 24-hr. Corr. Mean Temp: 47.0F [+0.7F] Max Temp: 72F on 9th, 19th, 24th Min Temp: 26F on 4th Total heating degree day units (month): 502 [ -49] *NCDC method Total heating degree day units (season): 5,522 [-513] *start July 1 (NCDC) PRECIPITATION: Total precipitation: 2.29 inches [-2.26 inches] Greatest 24-hr precipitation: 0.61 inches on 11th/12th Total snowfall: Trace [-3.0 inches] Total seasonal snowfall: 99.0 inches [+36.3 inches] WIND: Avg wind speed: 13.3 MPH Avg corrected wind speed: 13.7 MPH Prevailing wind direction: S [14%] Peak gust: 51 MPH S on 7th Peak fastest mile: 40 MPH S on 7th SUNSHINE: Astronomical minutes: 14,392 of possible 24,094 or 60% Campbell-Stokes card minutes: 13,872* of possible 23,250 or 60% *Corrected total Today's observations: 7 A.M. Weather: Clear, few stratocumulus and cumulus fractus NNE-S, few altocumulus WNW-N, hazy Temperature: 49F; Dew Point: 40F; Wind: ENE at 8 kts, Sea-level pressure: 30.36 ins. Hg, rising Visibility: 50 miles, hazy 6-hour min. temp: 49F BHO SA 1155 CLR 50 281/49/40/0608/036/ FEW SC/CUFRA NNE-S FEW AC WNW-N HAZY/ 8/570 53003 10049 20044 10 A.M. Weather: Scattered cumulus, few lower cumulus fractus overhead, hazy Temperature: 52F; Dew Point: 37F; Wind: ENE at 10 kts, Wind: Direction variable NE-ESE Sea-level pressure: 30.37 ins. Hg, rising slightly Visibility: 35 miles, hazy BHO SA 1455 30 SCT 35 285/52/37/0710/037/ FEW LWR CUFRA OVHD HAZY WND 04V10/ 8/100 50004 1 P.M. Weather: Clear, few cumulus and cumulus fractus distant E-SE, thin smoke/haze layer aloft NW-NE Temperature: 52F; Dew Point: 34F; Wind: ENE at 12 kts, Wind: Direction variable NE-ESE Sea-level pressure: 30.37 ins. Hg, falling slightly Visibility: 35 miles, hazy 6-hour max. temp: 55F BHO SA 1755 CLR 35 284/52/34/0712/037/ FEW CU/CUFRA DSNT E-SE THN K/HZ LYR ALF NW-NE HAZY WND 04V10/ 8/100 58001 10055 20049 WEATHER SUMMARY FOR FRIDAY, MAY 3, 2013 TEMPERATURE (DEGREES F) MAX.....54 NORMAL.....63 MIN.....42 NORMAL.....44 MEAN....48 NORMAL.....53 DEPARTURE FROM 30-YEAR NORMAL....................-5 TOTAL DEPARTURE FOR THE MONTH....................+4 [+1.1 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............17 DEPARTURE..........+5 TOTAL HEATING UNITS FOR THE MONTH............32 DEPARTURE..........-5 TOTAL HEATING UNITS FOR THE SEASON.........5554 DEPARTURE........-518 TOTAL HEATING UNITS LAST SEASON TO DATE....4769 DIFFERENCE.......+785 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............24 NE AT 8:03 A.M. AERO....................25 NE AT 8:03 A.M. * ASOS....................26 ENE AT 11:05 A.M. DAVIS...................26 N AT 7:52 A.M. RMY: 28 THE FASTEST MILE FOR YESTERDAY.............19 NE AT 10:09 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE..............20 NE AT 8:45 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............18 NNE AT 8:45 A.M. AVERAGE WIND SPEED AND DIRECTION.........11.1 NE ASOS..................10.0 DAVIS..................9.7 NE [040 deg] * Last of several occurrences PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE...........-0.13 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH.........Trace DEPARTURE...........-0.37 ASOS..............0.00 TOTAL PRECIPITATION FOR THE YEAR..........16.38 DEPARTURE...........-2.54 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 APRIL AND 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 4/1 61/31/46/+5/0.34/0.0/458/60 40 W AERO 44 MPH WNW RMY 46 TSTM 4/2 40/27/34/-7/T/T/460/60 45 W AERO 42 MPH W RMY 47 4/3 45/27/36/-6/0.00/0.0/755/98 44 W AERO 43 MPH W RMY 47 4/4 55/26/41/-1/0.00/0.0/719/93 30 WSW AERO 27 MPH WSW RMY 31 4/5 59/36/48/+5/0.00/0.0/403/52 33 NNW AERO 28 MPH NNW RMY 38 4/6 47/30/39/-4/0.00/0.0/747/96 38 NW AERO 35 MPH NW RMY 40 4/7 52/31/42/-1/0.00/0.0/391/50 51 S AERO 46 MPH S RMY 50 4/8 65/43/54/+10/T/0.0/494/63 29 SSW AERO 22 MPH SSW RMY N/A 4/9 72/44/58/+14/T/0.0/456/58 35 WNW AERO 35 MPH WNW RMY 39 TSTM 4/10 64/43/54/+9/0.13/0.0/426/54 23 SE AERO 20 MPH SE RMY 25 4/11 52/40/46/+1/0.09/0.0/063/08 18 ENE AERO 14 MPH ENE RMY N/A 4/12 40/34/37/-8/0.58/T/000/00 38 E AERO 32 MPH E RMY 41 4/13 52/34/43/-3/0.04/0.0/128/16 31 NNE AERO 27 MPH NNE RMY 31 4/14 52/36/44/-2/0.00/0.0/216/27 31 WNW AERO 27 MPH WNW RMY 32 4/15 55/35/45/-2/0.00/0.0/514/64 21 ESE AERO 15 MPH S RMY N/A 4/16 62/38/50/+3/T/0.0/540/67 44 S AERO 40 MPH S RMY 45 4/17 67/48/58/+11/T/0.0/769/95 29 SSW AERO 25 MPH SSW RMY N/A 4/18 65/43/54/+6/0.00/0.0/503/62 30 S AERO 25 MPH S RMY N/A 4/19 72/50/61/+13/0.07/0.0/195/24 47 SSW AERO 48 MPH SSW RMY 50 4/20 62/39/51/+2/0.48/0.0/147/18 43 SSW AERO 41 MPH SSW RMY N/A 4/21 53/31/42/-7/0.00/0.0/819/100 31 WNW AERO 25 MPH WNW RMY N/A 4/22 49/35/42/-7/0.00/0.0/551/67 32 E AERO 28 MPH E RMY 33 4/23 40/38/39/-11/0.50/0.0/000/00 35 NNE AERO 30 MPH NNE RMY 35 4/24 72/40/56/+6/0.01/0.0/463/56 36 SSW AERO 33 MPH SSW RMY N/A 4/25 64/44/54/+4/0.05/0.0/581/70 38 W AERO 32 MPH W RMY N/A 4/26 58/42/50/-1/0.00/0.0/607/73 28 ENE AERO 22 MPH ENE RMY N/A 4/27 62/42/52/+1/0.00/0.0/802/96 21 S AERO 17 MPH S RMY 22 4/28 69/44/57/+5/0.00/0.0/771/92 25 S AERO 21 MPH S RMY 27 4/29 69/46/58/+6/0.00/0.0/697/83 25 S AERO 30 MPH S RMY 26 4/30 67/47/57/+5/0.00/0.0/717/85 23 ENE AERO 21 MPH ENE RMY 23 5/1 67/45/56/+3/0.00/.../.. 18 E AERO 16 MPH E RMY 17 5/2 75/43/59/+6/T/.../.. 29 NE AERO 26 MPH NE RMY 29 5/3 54/42/48/-5/0.00/.../.. 24 NE AERO 25 MPH NE RMY 28 5/4 morning low temp: 44F; the normal low is now 44F DAILY RECORDS FOR APRIL 2013 None 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 4 HIGH 90F IN 2001 LOW 27F IN 1911 (RECORD FOR MAY) PRECIP 1.92 INCHES IN 1893 SNOWFALL 0.1 INCHES IN 1920 PEAK GUST 60 MPH NW IN 1966 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 TODAY'S REPORT PREPARED BY: Mike Iacono