BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, AUGUST 23, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME EARLY MORNING COLD FRONT PASSAGE USHERS IN DRIER, COOLER AIR MASS A cold front moved through the area early this morning, switching the wind direction from SW to NW (check out member content at bluehill.org for more info). A cooler and drier air mass is invading the region as a result. The dew point temperature has fallen into the upper 50s this afternoon, down from the upper 60's of this morning prior to the frontal passage. The high temperature has only reached the upper 70s today. Only a rumble of thunder was observed yesterday ahead of the front. No precipitation fell on the summit in association with the front. The relative dry streak continues as a result. Today's Observations: 7 A.M. Weather: Scattered altocumulus (3 levels), scattered dense cirrus, broken thin cirrus, lower altocumulus and a few altocumulus castellanus distant E-S, few altocumulus lenticularis all quadrants, thin smoke layer distant all quadrants, hazy Temperature: 69F; Dew Point: 61F; Wind: NNW at 11G21 kts, Wind: Direction variable WNW-N Sea-level pressure: 29.92 ins. Hg, rising Visibility: 45 miles, hazy 6-hr min. temp: 67F BHO SA 1155 100 SCT 140 SCT 180 SCT 220 SCT 250 –BKN 45 132/69/61/3311G21/992 LWR AC AND FEW ACC DSNT E-S FEW ACSL ALQDS THN K LYR DSNT ALQDS HAZY WND 29V36/ 8/082 52024 10069 20067 10 A.M. Weather: Scattered cumulus, scattered stratocumulus, scattered altocumulus (2 levels), broken cirrostratus, broken cirrus, few cumulus all quadrants, few stratocumulus lenticularis W-NW, few altocumulus castellanus distant ESE-SSE, partial halo, distant haze, thin smoke layer distant S-W-NNE Temperature: 72F; Dew Point: 60F; Wind: NNW at 7 kts, Wind: Direction variable WNW-NNE Sea-level pressure: 29.97 ins. Hg, rising Visibility: 55 miles, distant haze BHO SA 1455 30 SCT 50 SCT 120 SCT 140 SCT 200 BKN 250 BKN 55 149/72/60/3407/997/ FEW CU ALQDS FEW SCSL W-NW FEW ACC DSNT ESE-SSE PARTIAL HALO DSNT HZ THN K LYR DSNT S-W-NNE WND 30V02/ 8/187 53017 1 P.M. Weather: Scattered cumulus, scattered altocumulus (2 levels), scattered dense cirrus, broken thin cirrus, cumulus and moderate cumulus mostly S-W-NW, few altocumulus lenticularis ESE-SSE, distant haze Temperature: 76F; Dew Point: 59F; Wind: ENE at 7 kts, Wind: Direction variable NE-ESE Sea-level pressure: 29.97 30.12 ins. Hg, rising slightly Visibility: 65 miles, distant haze 6-hr max. temp: 78F BHO SA 1755 40 SCT 100 SCT 120 SCT 220 SCT 250 –BKN 65 150/76/59/0707/997 CU AND MDT CU MSTLY S-W-NE FEW ACSL DSNT ESE-SSE DSNT HZ WND 04V11/ 8/242 53001 10078 20069 WEATHER SUMMARY FOR THURSDAY, AUGUST 22, 2013 TEMPERATURE (DEGREES F) MAX.....84 NORMAL.....79 MIN.....67 NORMAL.....61 MEAN....76 NORMAL.....70 DEPARTURE FROM 30-YEAR NORMAL.......................+6 TOTAL DEPARTURE FOR THE MONTH......................-28 [-1.5 DEGREES/DAY] COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY.............11 DEPARTURE.........+6 TOTAL COOLING UNITS FOR THE MONTH............111 DEPARTURE........-33 TOTAL COOLING UNITS FOR THE SEASON...........594 DEPARTURE........+99 TOTAL COOLING UNITS LAST SEASON TO DATE......651 DIFFERENCE.......-57 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY................22 SW AT 5:33 P.M. AERO.....................22 SSW AT 7:31 P.M. * ASOS.....................23 SSW AT 7:40 P.M. DAVIS....................22 SSW AT 6:21 P.M. RMY: N/A FASTEST MILE FOR YESTERDAY..................17 SSW AT 7:31 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE...............17 SSW AT 7:49 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..............17 SSW AT 7:08 P.M. AVERAGE WIND SPEED AND DIRECTION..........11.6 SW ASOS...................11.2 DAVIS..................10.6 SW [220] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M... 0.00 DEPARTURE............-0.12 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........2.55 DEPARTURE............-0.45 ASOS..............2.60 TOTAL PRECIPITATION FOR THE YEAR..........37.84 DEPARTURE............+3.85 ASOS..............N/A* *ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals PRELIMINARY CLIMATE SUMMARY FOR AUGUST 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 8/1 81/62/72/0/0.01/503/58 25 S AERO 26 MPH S RMY 27 8/2 81/62/72/0/0.23/518/60 26 W AERO 26 MPH W RMY 28 8/3 77/63/70/-2/T/276/32 22 WSW AERO 23 MPH WSW RMY 23 8/4 79/58/69/-3/T/645/75 25 WNW AERO 21 MPH WNW RMY 26 8/5 75/54/65/-7/0.00/858/100 26 WNW AERO 25 MPH WNW RMY 27 8/6 78/56/67/-5/0.00/846/99 17 ESE AERO 15 MPH S RMY 16 8/7 80/59/70/-2/0.00/759/89 21 S AERO 21 MPH S RMY N/A 8/8 79/62/71/-1/0.08/153/18 25 S AERO 25 MPH S RMY N/A 8/9 73/70/72/0/2.21/000/00 37 S AERO 39 MPH S RMY 40 8/10 81/61/71/-1/0.00/795/94 30 WNW AERO 31 MPH WNW RMY 31 8/11 78/58/68/-3/0.00/835/99 18 W AERO 18 MPH W RMY 21 8/12 81/62/72/+1/0.00/656/78 18 W AERO 17 MPH WSW RMY 19 8/13 73/64/69/-2/0.02/193/23 16 SSE AERO 15 MPH SSE RMY N/A 8/14 73/57/65/-6/0.00/819/98 35 W AERO 35 MPH W RMY 35 8/15 75/53/64/-7/0.00/800/96 23 W AERO 23 MPH W RMY 24 8/16 77/57/67/-4/0.00/740/89 20 W AERO 19 MPH W RMY 21 8/17 77/59/68/-3/0.00/770/93 18 W AERO 18 MPH W RMY N/A 8/18 80/62/71/0/T/231/28 16 SSW AERO 17 MPH SSW RMY 18 8/19 82/58/70/0/T/494/60 17 W AERO 18 MPH W RMY 20 8/20 85/64/75/+5/0.00/772/94 17 NW AERO 18 MPH NW RMY N/A 8/21 87/65/76/+6/0.00/802/98 18 WSW AERO 18 MPH WSW RMY 18 8/22 84/67/76/+6/0.00/.../.. 22 SW AERO 22 MPH SSW RMY N/A 8/23 morning low temp: 67F; the normal low is now 61F DAILY RECORDS FOR AUGUST 2013 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR AUGUST 23 HIGH 88F IN 1918, 1947, 1949, 1996 LOW 45F IN 1923 PRECIP 2.09 INCHES IN 2010 PEAK GUST 60e MPH NW IN 1940 RECORDS FOR AUGUST 24 HIGH 92F IN 1947 LOW 43F IN 1971 PRECIP 2.40 INCHES IN 2010 PEAK GUST 54 MPH W IN 1986 TODAY'S REPORT PREPARED BY: Sean Fankhauser