BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, APRIL 17, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME ANOTHER VERY WARM, VERY DRY, AND VERY SUNNY DAY While it's not nearly as hot as it was yesterday, temperatures are still running about 20 degrees above normal. Monday's heat set a new record high temperature of 89F, beating the VERY old record of 87F set in 1896. Yesterday's warmth did NOT, however, set a new record high minimum temperature, as temperatures cooled to 57F by midnight last night, failing to beat the record of 59F in 1976. The record high for today of 93F set in 2002 will be out of reach. The air mass is notably drier today. Dew point temperatures began the day in the upper 50s and have since dropped into the mid 30s, pushing relative humidity values down to the upper teens. Visibility has improved dramatically with the drier air mass, increasing to 75 miles this afternoon. Sunshine has been uninterrupted today, with only scattered clouds to the SE and NW of the summit. The 0.76 inch of precipitation that we've received on the summit from March 4 - April 16 (over 6 weeks) is just less than 10% of the normal precipitation (7.72) that would be expected in that time frame. Today's observations: 7 A.M. Weather: Scattered thin cirrus, cirrus distant WSW-N, smoke/haze layer distant all quadrants, smoke/haze layer aloft SW-N, hazy Temperature: 66F, Dew point: 57F, Wind: WNW at 9 kts, Sea-level pressure: 30.00 inches Hg, rising Visibility: 35 miles, N-E-S 30 miles, WNW 55 miles above inversion, hazy 6-hour min. temp: 53F BHO SA 1155 250 –SCT 35 158/66/57/3009/000/ CI DSNT WSW-N K/HZ LYR DSNT ALQDS K/HZ LYR ALF SW-N HAZY VSBY N-E-S 30 WNW 55 ABV INVSN/ 8/001 51027 10066 20053 10 A.M. Weather: Scattered altocumulus (2 levels), scattered thin cirrus, few altocumulus/altocumulus castellanus E-SSW, few altocumulus/altocumulus lenticularis distant W-N, few cirrus all quadrants except NW-NNW, distant haze Temperature: 77F, Dew Point: 44F; Wind: WNW at 14G18 kts, Sea-level pressure: 30.03 inches Hg, rising Visibility: 70 miles, distant haze BHO SA 1455 100 SCT 120 SCT 250 –SCT 70 168/77/44/2914G18/003/ FEW AC/ACC E-SSW FEW AC/ACSL DSNT W-N FEW CI ALQDS XCPT NW-NNW DSNT HZ WND 26V33/ 8/081 53010 1 P.M. Weather: Scattered altocumulus, scattered cirrostratus, scattered thin cirrus (2 levels), altocumulus/altocumulus lenticularis SW-W-N, few altocumulus castellanus distant W-WNW, cirrostratus W-NNW invading, cirrus all quadrants, light distant haze Temperature: 82F, Dew Point: 34F; Wind: WNW at 12G17 kts, Wind: Direction variable W-NNW Sea-level pressure: 30.02 inches Hg, falling Visibility: 75 miles, light distant haze 6-hour max. temp: 82F BHO SA 1755 120 SCT 200 SCT 250 –SCT 300 –BKN 75 165/82/34/3012G17/002/ AC/ACSL SW-W-N FEW ACC DSNT W-WNW CS DSNT W-NNW INVADING CI ALQDS LGT DSNT HZ WND 27V33/ 8/085 58003 10082 20066 WEATHER SUMMARY FOR MONDAY, APRIL 16 TEMPERATURE (DEGREES F) MAX.....89 NORMAL.....56 MIN.....57 NORMAL.....38 MEAN....73 NORMAL.....47 DEPARTURE FROM 30-YEAR NORMAL......................+26 TOTAL DEPARTURE FOR THE MONTH......................+86 [+5.2 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY...............0 DEPARTURE.........-19 TOTAL HEATING UNITS FOR THE MONTH.............258 DEPARTURE.........-81 TOTAL HEATING UNITS FOR THE SEASON...........4543 DEPARTURE.......-1260 TOTAL HEATING UNITS LAST SEASON TO DATE......5722 DIFFERENCE......-1179 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............28 SSW AT 5:05 P.M. AERO..................30 SSW AT 5:04 P.M. * ASOS..................31 S AT 5:05 P.M. DAVIS.................30 S AT 2:37 P.M. THE FASTEST MILE FOR YESTERDAY...........26 SSW AT 5:05 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............25 SSW AT 5:06 P.M. DAVIS MAXIMUM 2-MINUTE AVERAGE...........25 S AT 5:05 P.M. AVERAGE WIND SPEED AND DIRECTION.......13.1 S ASOS................13.0 DAVIS...............12.1 SSW [197 deg.] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE..........-0.15 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........0.35 DEPARTURE..........-2.31 ASOS..............0.32 TOTAL PRECIPITATION FOR THE YEAR...........6.44 DEPARTURE.........-10.22 ASOS..............6.47 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE..........-0.1 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE..........-1.7 TOTAL SNOWFALL FOR THE SEASON..............24.2 DEPARTURE.........-34.4 PRELIMINARY CLIMATE SUMMARY FOR APRIL 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 4/1 50/34/42/+1/0.14/0.0/360/47 20 SSW AERO 20 MPH SSW RMY N/A 4/2 51/35/43/+2/0.04/T/353/46 35 NNW AERO 33 MPH NNW RMY 35 4/3 57/31/44/+2/0.00/0.0/724/94 36 NW AERO 37 MPH NW RMY 40 4/4 62/38/50/+8/T/0.0/688/89 40 NW AERO 39 MPH NW RMY 43 4/5 51/33/42/-1/0.00/0.0/660/85 29 NW AERO 27 MPH NW RMY 30 4/6 51/31/41/-2/0.00/0.0/623/80 26 NNW AERO 26 MPH NNW RMY 28 4/7 54/32/43/0/0.00/0.0/305/39 31 NW AERO 32 MPH NW RMY 32 4/8 51/37/44/0/0.00/0.0/086/11 32 NW AERO 31 MPH NW RMY 33 4/9 57/43/50/+6/T/0.0/323/41 44 W AERO 42 MPH W RMY 44 4/10 61/40/51/+6/0.00/0.0/600/76 32 W AERO 31 MPH W RMY 34 4/11 57/40/49/+4/0.00/0.0/397/50 21 NE AERO 20 MPH NE RMY 22 4/12 54/39/47/+2/0.16/0.0/.../.. 25 NNW AERO 24 MPH NNW RMY 28 4/13 63/36/50/+4/0.00/0.0/.../.. 24 W AERO 23 MPH W RMY 25 4/14 70/44/57/+11/0.00/0.0/.../.. 25 SSW AERO 27 MPH SSW RMY 28 4/15 75/52/64/+17/T/0.0/.../.. 23 W AERO 23 MPH W RMY 25 4/16 89/57/73/+26/0.01/0.0/.../.. 28 SSW AERO 30 MPH SSW RMY 32 4/17 the morning low temp: 53F; the normal low is now 38F DAILY RECORDS FOR APRIL 2012 4/16 - NEW DAILY RECORD HIGH MAXIMUM TEMP OF 89F; surpasses the previous record of 87F in 1896. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 17 HIGH 93 IN 2002 LOW 21 IN 1908 PRECIP 1.68 IN 1954 SNOWFALL 1.0 IN. IN 1899 PEAK GUST 63 MPH ESE IN 2011 RECORDS FOR APRIL 18 HIGH 92 IN 1976 LOW 23 1887 PRECIP 1.48 IN 1954 SNOWFALL 3.7 IN. IN 1965 PEAK GUST 59 MPH S IN 1982 TODAY'S REPORT PREPARED BY: Sean Fankhauser