BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, JUNE 12, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME MOSTLY CLOUDY SKIES AND MARITIME AIR MASS KEEPING TEMPERATURES IN CHECK Some filtered sunshine has been observed today through the mostly cloudy sky. Clouds have been increasing ahead of an approaching storm system that is expected to bring rainfall to the region overnight and through Wednesday. Pressure is slowly falling ahead of the approaching system. Winds have generally been from the south since Wednesday afternoon, but the air mass being advected into the region is of a maritime origin. High pressure off the East Coast, with it's clockwise circulation, is bringing the maritime air mass into the region. Consequently, and because of the cloud cover, temperatures are averaging fairly close to normal for the day, if not slightly on the cool side. Moisture has increased over the past 24 hours, with dew points reaching the mid and upper 50s today. As a result, conditions have been hazy, with visibility only reaching about 45 miles this afternoon. Sunshine for the month is only at 40.3% of possible through June 10. Today's observations: 7 A.M. Weather: Scattered cumulus, broken stratocumulus, broken cirrostratus, broken cirrus, few cumulus fractus all quadrants, few altocumulus lenticularis distant NE-SE, cirrostratus S-W-NNW invading the sky, cirrus layer partly thin, hazy Temperature: 62F, Dew Point: 57F; Wind: S at 11 kts. Sea-level pressure: 30.16 inches Hg, falling Visibility: 30 miles, hazy 6-hour min. temp: 57F BHO SA 1155 10 SCT E80 BKN 200 BKN 250 BKN 30 213/62/57/1911/016/ FEW CUFRA ALQDS FEW ACC DSNT NE-SE CS S-W-NNW INVADING CI LYR PRTLY THN HAZY/ 8/186 56010 10062 20057 10 A.M. Weather: Scattered cumulus, scattered altocumulus castellanus, broken altocumulus, broken altostratus, overcast cirrostratus, cumulus/cumulus fractus distant ESE-SW-NW, altocumulus castellanus NNE-S, few thin spots in overcast NE-E, halo, hazy Temperature: 70F, Dew Point: 58F; Wind: S at 11 kts, Wind: Direction variable SSE-SW Sea-level pressure: 30.13 inches Hg, falling Visibility: 45 miles, hazy BHO SA 1455 20 SCT 60 SCT E80 BKN 160 BKN 200 OVC 45 203/70/58/1811/013/ CU/CUFRA DSNT ESE-SW-NW ACC NNE-S FEW THN SPTS INOVC NE-E HALO HAZY WND 15V22/ 8/187 56010 1 P.M. Weather: Scattered cumulus, broken altocumulus (3 levels), broken cirrostratus, few moderate cumulus SSE-SW, altocumulus chaotic, hazy Temperature: 72F, Dew Point: 58F; Wind: S at 15 kts, Wind: Direction variable SSE-SW Sea-level pressure: 30.09 inches Hg, falling Visibility: 45 miles, hazy 6-hour max. temp: 72F BHO SA 1755 30 SCT E60 BKN 80 BKN 120 BKN 200 BKN 45 190/72/58/1915/009/ FEW MDT CU SSE-SW AC CHAOTIC HAZY WND 15V22/ 8/297 58013 10072 20062 WEATHER SUMMARY FOR MONDAY, JUNE 11 TEMPERATURE (DEGREES F) MAX.....76 NORMAL.....74 MIN.....55 NORMAL.....56 MEAN....66 NORMAL.....65 DEPARTURE FROM 30-YEAR NORMAL.......................+1 TOTAL DEPARTURE FOR THE MONTH......................-44 [-4.2 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY...............0 DEPARTURE..........-3 TOTAL HEATING UNITS FOR THE MONTH..............66 DEPARTURE.........+24 TOTAL HEATING UNITS FOR THE SEASON...........4954 DEPARTURE.......-1385 TOTAL HEATING UNITS LAST SEASON TO DATE......6189 DIFFERENCE......-1235 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............23 S AT 7:11 P.M. * AERO..................21 S AT 4:00 P.M. ASOS..................23 S AT 4:00 P.M. DAVIS.................21 S AT 5:03 P.M. RMY 22 THE FASTEST MILE FOR YESTERDAY...........16 S AT 11:26 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............17 S AT 5:03 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........17 S AT 5:03 P.M. AVERAGE WIND SPEED AND DIRECTION.......10.3 S ASOS................10.2 DAVIS................9.4 S [178] * last of several occurrences. PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE...........-0.16 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.93 DEPARTURE...........+0.11 ASOS..............1.87 TOTAL PRECIPITATION FOR THE YEAR..........15.17 DEPARTURE...........-9.31 ASOS.............15.12 PRELIMINARY CLIMATE SUMMARY FOR JUNE 2012 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/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 6/1 67/53/60/-2/0.00/742/82 28 ENE AERO 28 MPH ENE RMY 29 6/2 63/52/58/-4/0.80/000/00 39 SE AERO 39 MPH SE RMY 40 6/3 62/50/56/-6/0.01/082/09 31 N AERO 28 MPH N RMY 29 6/4 50/47/49/-14/..../000/00 44 NNE AERO 43 MPH NNE RMY 43 6/5 54/47/51/-12/..../009/01 23 NNE AERO 18 MPH NNE RMY N/A 6/6 63/48/56/-7/0.01/310/34 16 ENE AERO 14 MPH ENE RMY 15 6/7 70/50/60/-4/0.27/328/36 31 NE AERO 31 MPH NE RMY 32 TSTM 6/8 76/51/64/0/0.03/502/55 25 WSW AERO 25 MPH WNW RMY 26 TSTM 6/9 76/56/66/+2/0.00/822/90 25 WNW AERO 24 MPH WNW RMY 24 6/10 78/56/67/+2/0.00/868/95 21 E AERO 18 MPH E RMY 18 6/11 76/55/66/+1/0.00/.../.. 23 S AERO 21 MPH S RMY 22 6/12 morning low temp: 57F; the normal low is now 56F DAILY RECORDS FOR JUNE 2012 6/4 - NEW DAILY RECORD LOW MAXIMUM TEMP OF 50F; surpasses the previous record of 51F in 1891. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR JUNE 12 HIGH 92F IN 1973 LOW 40F IN 1906 PRECIP 1.79 INS 1955 PEAK GUST 58 MPH NW IN 1991 RECORDS FOR JUNE 13 HIGH 93F IN 1988 LOW 43F IN 1982 PRECIP 6.07 INS 1998 [Record for month] PEAK GUST 69 MPH N IN 1956 TODAY'S REPORT PREPARED BY: Sean Fankhauser