BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, SEPTEMBER 1, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME COOLER AND DRIER AIR RETURNS TODAY...VERY LIGHT RAIN SHOWER FRIDAY EVENING...AUGUST SECOND DRIEST ON RECORD...SUMMER 2007 SLIGHTLY WARMER AND MUCH DRIER THAN AVERAGE... A scant 0.01 inch of rainfall was measured just before midnight last night bringing the final rainfall total for August to just 0.63 inch. This makes last month the second driest August on record, behind only 0.53 inch in 1981. There were only seven days with measureable precipitation last month and two of these were just 0.01 inch. Only 0.17 inch of rainfall has been observed here on the summit over the last three weeks. The July-August total rainfall was 4.01 inch, which is the tenth driest for these two months combined. The summer (June-August) rainfall of 6.83 inches was about 58% of the average for summer. The dew point has dropped into the middle 40s this afternoon with the temperature in the 70s. Visibility is approaching 80 miles this afternoon under a mostly sunny sky. Driest Augusts (inches) 1) 0.53 in 1981 2) 0.63 in 2007 3) 0.91 in 1984 4) 1.05 in 1910 5) 1.22 in 1948 August 2007 Summary Avg Max Temp: 81.0 deg F [+2.1] Avg Min Temp: 62.2 deg F [+1.3] Average Temp: 71.6 Deg F [+1.7] Corrected Mean Temp: 70.5 deg F Highest Temp: 93 deg F [25th] Lowest Temp: 51 deg F [19th] Precipitation: 0.63 inch [-3.43] Heating Degree Days: 19 [-3] Cooling Degree Days: 229 [+56] Average Wind Speed: 10.8 mph, S Peak Wind Gust: 46 mph WNW [18th] Mean Vapor Pressure: 17.8 mb Sunshine: 65% (not final) Summer 2007 Summary (June-August) Avg Max Temp: 79.3 deg F [+0.8] Avg Min Temp: 60.2 deg F [+0.6] Average Temp: 69.8 Deg F [+0.7] Corrected Mean Temp: 68.8 deg F Highest Temp: 93 deg F [6/27 and 8/25] Lowest Temp: 44 deg F [6/7] Precipitation: 6.83 inches [-4.90] Today's observations: 7 A.M. Weather: Clear, few altocumulus Temperature: 62F, Dew point: 51F, Wind: NW at 10 kts Wind: variable W-N Sea-level pressure: 30.08 inches Hg, rising Visibility: 45 miles 6-hour min temp: 57F 24-hour rainfall: 0.01 BHO SA 1155 CLR 45 185/62/51/3110/008/ FEW AC DSNT WSW-WNW WND 27V35/ 8/030 51020 70001 10064 20057 10 A.M. Weather: Scattered cumulus Temperature: 72F, Dew point: 50F, Wind: NW at 10 kts Wind: variable W-N Sea-level pressure: 30.09 inches Hg, rising Visibility: 50 miles BHO SA 1455 45 SCT 50 188/72/50/3110/009/ WND 27V35/ 8/100 51003 1 P.M. Weather: Broken cumulus Temperature: 75F, Dew point: 45F, Wind: NW at 10 kts Wind: variable W-N Sea-level pressure: 30.10 inches Hg, rising Visibility: 75 miles 6-hour max. temp: 78 deg. F BHO SA 1755 E50 BKN 75 191/75/45/3210/010/ WND 28V36/ 8/100 50003 10079 20062 WEATHER SUMMARY FOR FRIDAY, AUGUST 31 TEMPERATURE (DEGREES F) MAX.....78 NORMAL.....76 MIN.....65 NORMAL.....58 MEAN....72 NORMAL.....67 DEPARTURE FROM 30-YEAR NORMAL.........+5 TOTAL DEPARTURE FOR THE MONTH........+58 (+1.7 DEGREES/DAY) PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY..............28 NNE AT 3:26 P.M. AEROVANE...............24 NNE AT 3:26 P.M. ASOS...................N/A # DAVIS..................26 NNE AT 3:25 P.M. FASTEST MILE FOR YESTERDAY................17 NNW AT 3:26 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE.............N/A # MAXIMUM 2-MINUTE DAVIS AVERAGE............18 NE AT 2:55 P.M. AVERAGE WIND SPEED AND DIRECTION..........9.5 NNW ASOS...................N/A # DAVIS..................8.8 NNE [23 deg] * last of several occurrences.. # ASOS WINDS SWITCHED OFF BY NWS 6/6, IT IS NOT KNOWN WHEN THAT DATA WILL RESUME PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.01 DEPARTURE.....-0.13 ASOS..............0.01 TOTAL PRECIPITATION FOR THE MONTH..........0.63 DEPARTURE.....-3.43 ASOS..............0.56 TOTAL PRECIPITATION FOR THE YEAR..........30.99 DEPARTURE.....-2.48 ASOS.............30.23 PRELIMINARY CLIMATE SUMMARY FOR AUGUST 2007......CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available 8/1 84/67/76/+4/0/851/98 20 NNE 8/2 92/68/80/+8/0/823/95 21 S 8/3 92/70/81/+9/0/760/88 28 SSW 8/4 89/71/80/+8/0/827/96 29 WSW 8/5 80/62/71/-1/0/842/98 23 SSE 8/6 77/61/69/-3/0.05/129/15 36 SSE Aero 34 MPH SSE TSTM 8/7 82/67/75/+4/0.12/410/48 15 SSE 8/8 88/70/79/+8/0.10/349/41 36 S 8/9 75/60/68/-3/0/722/85 32 NW 8/10 63/53/58/-13/0.19/017/02 16 SSW 8/11 83/52/68/-3/0/743/88 21 WNW 8/12 86/64/75/+4/0/665/79 21 SSW 8/13 83/64/74/+3/0.01/260/31 30 NW TSTM 8/14 78/58/68/-2/0/812/97 23 NW 8/15 83/59/71/+1/0/651/78 36 SSW Aero 34 MPH SSW 8/16 87/67/77/+7/0/641/77 33 SSW 8/17 78/62/70/0/0.07/241/29 43 S Aero 39 MPH S TSTM 8/18 71/52/62/-8/0.08/761/92 46 WNW Aero 42 MPH WNW, Davis 46 MPH WNW TSTM 8/19 74/51/63/-7/0/619/75 25 WNW 8/20 70/56/63/-6/0/411/50 21 ENE 8/21 68/56/62/-7/0/271/33 23 E 8/22 70/55/63/-6/0/147/18 23 NE 8/23 75/59/67/-2/T/024/03 22 SSE 8/24 88/66/77/+8/0/552/68 30 SSW 8/25 93/69/81/+13/0/566/70 25 SSE 8/26 84/68/76/+8/T/169/21 22 S 8/27 79/64/72/+4/0/731/91 25 NNE 8/28 83/64/74/+6/0/736/92 21 ESE 8/29 88/64/76/+9/0/782/98 24 SSE Aero 21 MPH SSE 8/30 89/65/77/+10/0/.../.. 23 S Aero 20 MPH SSE 8/31 78/65/72/+5/0.01/.../.. 28 NNE Aero 24 MPH NNE 9/1 morning low temp. 57F; normal low now 58F NEW DAILY RECORDS FOR AUGUST 2007: 8/18 - NEW RECORD PEAK GUST FOR OF 46 MPH WNW; the previous record was 39 MPH SW in 1991 8/25 - RECORD HIGH TEMPERATURE OF 93F; ties previous record set in 1947,1948 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR SEPTEMBER 1 HIGH 93F IN 1969 LOW 47F IN 1975 PRECIP 1.60 INCHES IN 1927 PEAK GUST 59e MPH S IN 1945, SSW IN 1965 RECORDS FOR SEPTEMBER 2 HIGH 99F IN 1953 (SEPTEMBER MAXIMUM RECORD) LOW 44F IN 1909 PRECIP 2.73 INCHES IN 1947 PEAK GUST 55e MPH WNW IN 1944 TODAY'S REPORT PREPARED By: Mike Iacono If you do not wish to receive this Daily Discussion and Climate Summary from the Blue Hill Observatory, please send an email to sitemaster@bluehill.org.