BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, JULY 31, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME A LITTLE EARLY MORNING SUNSHINE BUT RAIN BEGINS BEFORE NOON AS VERY HUMID CONDITIONS RETURN SENDING THE DEW POINT TEMPERATURES INTO THE LOW 70'S We had almost two hours worth of sunshine early today before the clouds thickened and rain started shortly before noon. At 2 p.m. EDT a total of 0.22 inch has brought our monthly total to 7.34 inches and the month now ranks 8th wettest on record. Additional rainfall is likely to push the monthly total to over 7.55 inches making for the 6th wettest July on record. A high temperature of 81F was recorded just after 10 a.m. EDT this morning and it now appears that July will end up 3.2 degrees cooler than the 30-year average. The rankings for July precipitation in inches, dating back to 1886 are: 1. 11.67 in 1938 2. 10.66 in 1988 3. 10.43 in 1921 4. 9.52 in 1915 5. 8.47 in 1889 6. 7.55 in 1916 7. 7.41 in 1898 8. 7.34 in 2009 * 9. 7.31 in 1989 10. 6.66 in 1959 * through 2 PM EDT on the 31st. Today's observations: 7 A.M. Weather: High thin overcast, few altocumulus west to northwest, few cirrocumulus Temperature: 73F, Dew point: 64F, Wind: SE at 10 kts Sea-level pressure: 29.93 inches Hg, falling Visibility: 25 miles, hazy 24-hour precipitation: 0.25 inch 6-hour minimum temp: 67F BHO SA 1155 220 SCT 250 –OVC 25 136/73/64/1410/993/ AC/FEW ACSL W-NW FEW CC ALQDS HAZY WND GRDLY BACKING PST HR/ 8/047 58003 ASOS 70024 MANUAL 70025 10073 20067 10 A.M. Weather: Overcast altocumulus, few stratocumulus Temperature: 78F, Dew point: 68F, Wind: SSE at 13 kts Sea-level pressure: 29.90 inches Hg, falling Visibility: 15 miles BHO SA 1455 E130 OVC 15 124/78/68/1613/990/ FEW SC HZ INCRSNG/ 8/57/ 56012 1 P.M. Weather: Low stratus fractus overcast drifting over and below summit, light rain and drizzle Temperature: 72F, Dew point: 72F, Wind: SSE at 14G22 kts, Wind: direction variability SE to S Sea-level pressure: 29.83 inches Hg, falling Visibility: 1 mile, variable 3/4 to 1.5 miles 6-hourly max. temp: 81F 6-hourly precipitation: 0.22 inch BHO SA 1755 E3 OVC 1VR-L-F 101/72/72/1614G22/983/ STFRA DRFTG OVR AND BLO SMT VSBY 3/4V11/2 R- INTMT WND 13V19/ 8/7// 58023 ASOS 60021 MANUAL 6022/ 10081 20072 WEATHER SUMMARY FOR THURSDAY JULY 30 TEMPERATURE (DEGREES F) MAX.....84 NORMAL.....81 MIN.....69 NORMAL.....63 MEAN....77 NORMAL.....72 DEPARTURE FROM 30-YEAR AVERAGE..........+5 TOTAL DEPARTURE FOR THE MONTH..........-90 [-3.2 DEGREES/DAY] HEATING DEGREE DATA WILL RESUME IN SEPTEMBER PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............25 S AT 2:03 A.M. * AEROVANE..............25 S AT 1:48 A.M. ASOS..................25 SSE AT 2:05 A.M. DAVIS.................25 S AT 1:22 A.M. FASTEST MILE FOR YESTERDAY...............20 S AT 12:56 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE............20 S AT 12:58 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........19 S AT 12:57 A.M. AVERAGE WIND SPEED AND DIRECTION.......10.7 W ASOS................10.7 DAVIS...............10.1 SW [220 DEG] * last of several occurrences.... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.25 DEPARTURE....+0.13 ASOS..............0.24 TOTAL PRECIPITATION FOR THE MONTH..........7.12 DEPARTURE....+3.50 ASOS..............7.25 TOTAL PRECIPITATION FOR THE YEAR..........30.76 DEPARTURE....+1.47 ASOS.............31.90 PRELIMINARY CLIMATE SUMMARY FOR JULY 2009 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 7/1 62/57/60/-10/0.51/000/00 25 NNE TSTM 7/2 66/56/61/-9/1.00/000/00 29 SSW TSTM 7/3 75/58/67/-3/T/283/31 23 WSW 7/4 77/59/68/-2/0/838/92 43 W 7/5 78/54/66/-5/0/856/94 33 W 7/6 79/60/70/-1/0/883/97 20 SSE 7/7 66/58/62/-9/0.73/027/03 28 SE TSTM 7/8 67/56/62/-9/0.23/091/10 27 NNE TSTM 7/9 66/55/61/-10/0/689/76 23 NE 7/10 76/54/65/-6/0/896/99 21 SW 7/11 77/56/67/-5/0.29/686/76 36 S 7/12 78/60/69/-3/0.33/650/72 30 SSW TSTM 7/13 76/55/66/-6/0/802/89 32 SW 7/14 75/56/66/-6/0/567/63 25 WNW 7/15 79/55/67/-5/0/826/92 30 WSW 7/16 77/62/70/-2/T/161/18 30 S 7/17 86/65/76/+4/0.01/582/65 24 ESE 7/18 84/66/75/+3/0.35/447/50 25 SSW TSTM 7/19 80/62/71/-1/0/865/97 27 WSW 7/20 80/64/72/0/0/481/54 16 E 7/21 66/61/64/-8/0.62/000/00 29 NNE 7/22 77/61/69/-3/T/160/18 15 W 7/23 72/60/66/-6/0.68/195/22* 35 NE 7/24 69/60/65/-8/2.07/088/10* 46 NE AERO 45 NE 7/25 83/61/72/-1/0/766/87 30 SSE 7/26 82/68/75/+3/0.05/422/48 32 S 7/27 83/69/76/+4/0/588/67 30 S TSTM (no rain, (12-1AM) 7/28 86/67/77/+5/0/709/81 24 S 7/29 82/69/76/+4/0/070/08 29 S 7/30 84/69/77/+5/0.25/392/45 25 S TSTM 7/31 our morning low temp: 67F; the normal low is now 63F NEW DAILY RECORDS FOR JULY 2009 TO DATE... 7/24: New record peak gust 46 MPH NE at 3:32 A.M. surpasses previous record of 43 MPH S IN 2008 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR JULY 31 HIGH 95F IN 1917 LOW 50F IN 1895,1918 PRECIP 1.34 INCHES IN 1892 PEAK GUST 43e MPH WNW IN 1953, 43 SW IN 1971 RECORDS FOR AUGUST 1 HIGH 97F IN 1917 LOW 49F IN 1891 PRECIP 3.61 INCHES IN 1927 PEAK GUST 41 MPH NNW IN 1985 TODAY'S REPORT PREPARED BY: Robert Skilling