BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MAY 19, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME WARM AND SUNNY WITH ONLY A FEW CLOUDS TODAY... The sky has been nearly totally free of clouds today with only a band of thin cirrus visible to the southeast all day as a storm passes far offshore. The low temperature of 51 and the high so far of 72 will provide for another warmer than average day, and much of the next week looks to be near or above average for temperature. Other than a little distant haze, the visibility has been very good today in the 70-75 mile range due to a low relative humidity below 35% this afternoon. The thunderstorm on the 16th was the first of the year. This is relatively late, though it was not the latest first thunderstorm in any year. Looking back to 1950, this occurred on June 21st in 1971. Latest First Thunderstorm, (1950-2012): 1) 21 June 1971 2) 19 June 1978 3) 3 June 1960 4) 20 May 1968 5) 19 May 1964 6) 16 May 2012 Today's observations: 7 A.M. Weather: Clear, few cirrus distant E-S, light distant haze, thin smoke layer along horizon NNW-NNE (over city) Temperature: 58F, Dew Point: 42F; Wind: N at 5 kts, Wind: Light and variable Sea-level pressure: 30.19 inches Hg, rising Visibility: 75 miles, light distant haze 6-hour min. temp: 51F BHO SA 1155 CLR 75 222/58/42/3505/019/ FEW CI DSNT E-S LGT DSNT HZ THN K LYR ALG HRZN NNW-NNE WND LGT AND VRB/ 8/001 53010 10058 20051 10 A.M. Weather: Clear, few cirrus distant E-SSW, light distant haze, thin smoke layer NW-NNW Temperature: 67F, Dew Point: 40F; Wind: ENE at 6 kts, Wind: Light and variable Sea-level pressure: 30.18 inches Hg, falling slightly Visibility: 75 miles, light distant haze BHO SA 1455 CLR 75 219/67/40/0606/018/ FEW CI DSNT E-SSW LGT DSNT HZ THN K LYR NW-NNW WND LGT AND VRB/ 8/001 58003 1 P.M. Weather: Thin scattered cirrus, cirrus band E-SSW, light distant haze Temperature: 72F, Dew Point: 42F; Wind: NE at 7 kts, Wind: Direction variable N-E Sea-level pressure: 30.17 inches Hg, falling slowly Visibility: 70 miles, light distant haze BHO SA 1755 220 –SCT 70 218/72/42/0507/017/ CI BND E-SSW LGT DSNT HZ WND 01V09/ 8/001 58001 10072 20058 WEATHER SUMMARY FOR FRIDAY, MAY 18 TEMPERATURE (DEGREES F) MAX.....69 NORMAL.....67 MIN.....49 NORMAL.....48 MEAN....59 NORMAL.....58 DEPARTURE FROM 30-YEAR NORMAL........................+1 TOTAL DEPARTURE FOR THE MONTH.......................+21 [+1.0 DEGREE/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY...............6 DEPARTURE..........-2 TOTAL HEATING UNITS FOR THE MONTH.............159 DEPARTURE.........-31 TOTAL HEATING UNITS FOR THE SEASON...........4873 DEPARTURE.......-1343 TOTAL HEATING UNITS LAST SEASON TO DATE......6103 DIFFERENCE......-1230 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............17 ESE AT 6:21 P.M. AERO..................17 ESE AT 4:38 P.M. ASOS..................17 S AT 10:03 P.M. DAVIS.................17 ESE AT 6:22 P.M. RMY 17 THE FASTEST MILE FOR YESTERDAY...........13 SSW AT 10:05 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............13 SSW AT 10:42 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........13 SE AT 6:57 P.M. AVERAGE WIND SPEED AND DIRECTION....... 8.4 SSW ASOS.................7.2 DAVIS................7.1 SSE [160 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..........2.95 DEPARTURE..........+0.74 ASOS..............2.87 TOTAL PRECIPITATION FOR THE YEAR..........12.56 DEPARTURE..........-8.20 ASOS.............12.60 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/-2/0.01/0.0/000/00 21 SSW AERO 25 MPH SSW RMY 23 5/5 57/46/52/-2/0.04/0.0/034/04 14 NE AERO 15 MPH NE RMY 15 5/6 58/45/52/-2/0.00/0.0/532/62 21 ENE AERO 21 MPH ENE RMY 21 5/7 67/48/58/+3/0.00/0.0/740/86 23 S AERO 25 MPH S RMY 25 5/8 57/48/53/-2/0.18/0.0/000/00 40 S AERO 46 MPH S RMY 46 5/9 61/54/58/+3/0.36/0.0/000/00 25 S AERO 28 MPH S RMY N/A 5/10 65/46/56/+1/0.98/0.0/234/27 33 W AERO 36 MPH W RMY 37 5/11 62/42/52/-4/T/0.0/539/62 30 WNW AERO 33 MPH WNW RMY 34 5/12 77/46/62/+6/0.00/0.0/862/99 30 W AERO 30 MPH W RMY 29 5/13 82/57/70/+14/0.00/0.0/314/36 27 S AERO 29 MPH S RMY 29 5/14 71/52/62/+5/0.05/0.0/096/11 23 S AERO 24 MPH S RMY 23 5/15 72/57/65/+8/0.43/0.0/123/14 32 S AERO 35 MPH S RMY 33 5/16 71/58/65/+8/0.12/0.0/141/16 23 S AERO 24 MPH S RMY N/A 5/17 69/50/60/+3/0.00/0.0/.../.. 31 WNW AERO 32 MPH WNW RMY 26 5/18 69/49/59/+1/0.00/0.0/.../.. 17 ESE AERO 17 MPH ESE RMY 17 5/19 morning low temp: 51F; the normal low is now 49F DAILY RECORDS FOR MAY 2012 5/16 - Minimum temperature of 56F equals record high minimum for the date set in 1951 and 1961 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 19 HIGH 91F IN 1962 LOW 34F IN 2002 PRECIP 1.54 INCHES IN 1900 PEAK GUST 58 MPH NW IN 1964 RECORDS FOR MAY 20 HIGH 91F IN 1975,1996 LOW 37F IN 1948, 2002 PRECIP 1.65 INCHES IN 1969 PEAK GUST 57 MPH S IN 1963, WNW IN 1982 TODAY'S REPORT PREPARED BY: Mike Iacono/Peter Volpe