BLUE HILL OBSERVATORY MILTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, SEPTEMBER 3, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME RED SKY AT MORNING, SAILOR TAKE WARNING...! BEGINNING TO FEEL EFFECTS OF HURRICANE EARL HEAT WAVE COMES TO AN END NOT AS HOT, BUT HAZY AND HUMID TODAY We are beginning to feel some of the fringe effects of Hurricane Earl as it approaches the region from the south. A brief shower courtesy of one of Earl's rain bands brought a trace of rainfall to the summit around 12PM EST. The air has felt increasingly tropical through the day, with a dew point temperature now in the lower 70s. Winds have shifted from south and southwest earlier to southeast this afternoon. The pressure has been steadily dropping all day. With the increase in humidity and cloud cover, the backing winds, and the dropping pressure, we are beginning to feel the effects of Hurricane Earl! And, there is plenty more to come! The heat wave has officially ended. Today's high has only reached 83F, breaking the 90-degree streak of the past few days. Thursday's high temperature of 93F has put us in third place for the greatest yearly number of 90-degree days. The 1971-2000 average is only 7. GREATEST YEARLY NUMBER OF 90-DEGREE DAYS 1. 23 2002 23 1949 3. 20 1988 20 2010 (through September 3) Additional August Climate records and comparisons... GREATES AUGUST PRECIPITATION (INCHES) 1. 18.78 in 1955 2. 11.44 in 1946 3. 10.72 in 1927 4. 8.92 in 1976 5. 8.68 in 2010 6. 8.58 in 1917 WARMEST SUMMER (JUN-AUG) CORRECTED MEAN TEMPERATURE, DEG F 1. 71.3 in 2010 2. 70.8 in 1949 3. 70.6 in 1999 4. 70.4 in 1952 5. 70.2 in 2005 WARMEST JAN-AUG CORRECTED MEAN TEMPERATURE, DEG F 1. 53.0 in 2010 2. 52.0 in 1991 3. 51.9 in 1949 51.9 in 1998 51.9 in 2002 6. 51.7 in 1999 GREATEST JAN-AUG PRECIPITATION, INCHES 1. 58.58 in 1998 2. 47.00 in 1920 3. 46.03 in 2010 4. 44.04 in 1958 5. 43.56 in 2006 -Mike Iacono Today's observations: 7 A.M. Weather: Broken altocumulus, broken dense cirrus, broken thin cirrus, few altocumulus lenticularus east thru south, few altocumulus castellanus south thru southwest and west, altocumulus chaotic, patches of dense cirrus, hazy Temperature: 71F, Dew point: 66F; Wind: S at 9 kts Sea-level pressure: 29.89 inches Hg, falling slightly Visibility: 18 miles, hazy 6-hour minimum temp: 69F BHO SA 1155 E130 BKN 200 BKN 250 OVC 18 123/71/66/1809/989/ FEW ACSL E-S FEW ACC S-SW AND W AC CHAOTIC PTCHS DNS CI HAZY/ 8/092 58003 10072 20069 10 A.M. Weather: Broken altocumulus, broken dense cirrus, broken thin cirrus, few small cumulus distant south-southeast thru south-southwest, line of towering cumulus distant southeast thru south-southwest, cumulonimbus distant south, few altocumulus castellanus southeast thru south, few altocumulus lenticularus north thru north-northeast and south-southeast thru south and southwest thru north, altocumulus chaotic, patches dense cirrus, hazy Temperature: 78F, Dew point: 70F; Wind: WSW at 8 kts, Sea-level pressure: 29.83 inches Hg, falling Visibility: 20 miles, hazy BHO SA 1455 E130 BKN 200 BKN 250 OVC 20 103/78/70/2008/983/ FEW SML CU DSNT SSE-SSW LINE TCU DSNT SE-SSW CB DSNT S FEW ACC SE-S FEW ACSL N-NNE AND SSE-S AND SW-N AC CHAOTIC PTCHS DNS CI HAZY/ 8/992 58020 1 P.M. Weather: Scattered cumulus, broken altocumulus, overcast cirrus, line of small cumulonimbus east thru south moving northwest, few altocumulus lenticularus all quadrants except southwest thru northwest, altocumulus chaotic, dark sky distant south-southeast thru northwest, partial halo, hazy Temperature: 81F, Dew point: 73F; Wind: ESE at 9 kts, Sea-level pressure: 29.76 inches Hg, falling Visibility: 20 miles, hazy 6-hour rainfall: Trace 6-hour max. temp: 83F BHO SA 1755 30 SCT E120 BKN 200 OVC 20 077/81/73/1209/976/ LINE SML CBS E-S MVG NW FEW ACSL ALQDS XCPT SW-NW AC CHAOTIC DRK SKY DSNT SSE-NW PARTIAL HALO HAZY/ 8/397 58026 MANUAL 6000/ 10083 20071 WEATHER SUMMARY FOR THURSDAY, SEPTEMBER 2 TEMPERATURE (DEGREES F) MAX.....93 NORMAL.....75 MIN.....72 NORMAL.....57 MEAN....83 NORMAL.....66 DEPARTURE FROM 30-YEAR AVERAGE................+17 TOTAL DEPARTURE FOR THE MONTH.................+33 [16.3 DEGREES/DAY] PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............25 SSW AT 4:40 P.M. * AEROVANE..............29 SSW AT 4:41 P.M. * ASOS..................28 SW AT 4:41 P.M. DAVIS.................30 SSW AT 4:40 P.M. THE FASTEST MILE FOR YESTERDAY...........22 SSW AT 4:21 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE............21 SW AT 4:35 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........22 SSW AT 2:14 P.M. AVERAGE WIND SPEED AND DIRECTION.......12.3 SSW ASOS................12.3 DAVIS...............12.1 SSW [211 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 SEPTEMBER..........0.00 DEPARTURE........-0.26 ASOS..............0.00 TOTAL PRECIPITATION FOR THE YEAR..........46.03 DEPARTURE.......+12.30 ASOS.............45.84 ** ** ASOS missing rainfall due to system failure on 6/24-25 PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 2010 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 TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 9/1 93/73/83/+16/0.00/.../.. 18 SW 9/2 93/72/83/+17/0.00/.../.. 25 SSW 9/3 our morning low temp: 69F; the normal low is now 57F NEW DAILY RECORDS FOR SEPTEMBER 2010 9/1 - MAXIMUM TEMP. of 93F equals the previous record of 93F set in 1969 9/1 - HIGH MINIMUM TEMP. of 73F surpasses the previous record of 71F in 1898, 1969. 9/2 - HIGH MINIMUM TEMP. of 72F surpasses the previous record of 71F in 1959 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 3 HIGH 95F IN 1929 LOW 43F IN 1983 PRECIP 3.82 INCHES IN 1972 (TROPICAL STORM CARRIE) PEAK GUST 58 MPH NNE IN 1972 (TROPICAL STORM CARRIE) RECORDS FOR SEPTEMBER 4 HIGH 90F IN 1953, 1973 LOW 46F IN 1987 PRECIP 3.22 INCHES IN 1922 PEAK GUST 47 MPH SE IN 1966 TODAY'S REPORT PREPARED BY: Sean Fankhauser