BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, JULY 30, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME A BEAUTIFUL MID-SUMMER DAY A cold front cleared the air as it passed through the area late last night. The wind direction shifted from S to NW and eventually over to WNW, the prevailing direction today. A cooler and much drier and very pleasant air mass has taken over the region as a result. The dew point temperature has fallen by 10 degrees compared to yesterday, providing for a very comfortable feel to the air and great visibility that is reaching 70-75 miles today. With a low of 61F and a high barely breaking into the lower 80s, today's average temperature will likely finish just slightly below the 30-year normal for the date. Prior to the frontal passage yesterday, thunderstorms developed across Massachusetts, with one providing 0.10 inch of rain early in the afternoon. Additional thunderstorms that affected areas in and around Boston during the evening did not impact the summit at all. BHO Greatest Number of 90-Degree Days per Month, (1885-2013) 1) 14 in July 1952 2) 13 in August 2002 3) 10 in August 1944 10 in July 1949 10 in July 1963 10 in July 2010 10 in July 2013 (through 7/28) 8) 9 in July 1911 9 in August 1928 10) 8 in August 1949 8 in July 1963 8 in July 1988 Today's Observations: 7 A.M. Weather: Scattered dense cirrus, scattered thin cirrus, few altocumulus distant E-SE, cirrus and patches of dense cirrus distant NE-SSE, thin smoke layer along horizon all quadrants, thin smoke layer aloft distant SSW-W-N, light distant haze Temperature: 66F; Dew Point: 57F; Wind: WNW at 9 kts, Wind: Direction variable W-NW Sea-level pressure: 30.09 ins. Hg, rising Visibility: 70 miles, light distant haze 24-hr precip: 0.10 inch 6-hr min. temp: 61F BHO SA 1155 220 SCT 250 –SCT 70 191/66/57/3009/009/ FEW AC DSNT E-SE CI AND PTCHS DNS CI DSNT NE-SSE THN K LYR ALG HRZN ALQDS THN K LYR ALF DSNT SSW-W-N LGT DSNT HZ WND 26V32/ 8/072 51010 ASOS 70010 MANUAL 70010 10067 20061 10 A.M. Weather: Scattered thin cirrus, few cumulus forming distant WSW-NE, few moderate cumulus distant W-NW, few patches of dense cirrus W-WNW and distant NE-ESE cirrus distant NE-ESE and SW-NNW invading the sky, thin smoke layer distant all quadrants and aloft SW-NE, light distant haze Temperature: 75F; Dew Point: 60F; Wind: WNW at 10 kts, Wind: Direction variable W-NNW Sea-level pressure: 30.07 ins. Hg, falling Visibility: 70 miles, light distant haze BHO SA 1455 250 –SCT 70 183/75/60/3010/007/ FEW CU FRMG DSNT WSW-NE FEW MDT CU DSNT W-NW FEW PTCHS DNS CI W-WNW AND DSNT NE-ESE CI DSNT NE-ESE AND SW-NNW INVADING THN K LYR DSNT ALQDS ALF SW-NE LGT DSNT HZ WND 26V33/ 8/204 51007 1 P.M. Weather: Scattered cumulus, scattered dense cirrus, scattered thin cirrus, cumulus all quadrants, few moderate cumulus distant WSW-NE, few patches of dense cirrus distant ENE and distant WSW-W, thin smoke layer distant NNE-SE, light distant haze Temperature: 79F; Dew Point: 58F; Wind: W at 10 kts, Wind: Direction variable WSW-NW Sea-level pressure: 30.04 ins. Hg, falling Visibility: 75 miles, light distant haze 6-hr max. temp: 79F BHO SA 1755 45 SCT 220 SCT 250 –SCT 75 173/79/58/2810/004/ CU ALQDS FEW MDT CU DSNT WSW-NE FEW PTCHS DNS CI DSNT ENE AND DSNT WSW-W THN K LYR DSNT NNE-SE LGT DSNT HZ WND 25V32/ 8/202 58010 10079 20066 WEATHER SUMMARY FOR MONDAY, JULY 29, 2013 TEMPERATURE (DEGREES F) MAX.....81 NORMAL.....81 MIN.....66 NORMAL.....63 MEAN....74 NORMAL.....72 DEPARTURE FROM 30-YEAR NORMAL......................+2 TOTAL DEPARTURE FOR THE MONTH....................+114 [+3.7 DEGREES/DAY] PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY................20 S AT 3:42 P.M. * AERO.....................18 S AT 3:42 P.M. * ASOS.....................21 SSW AT 3:57 P.M. DAVIS....................20 S AT 3:57 P.M. RMY 21 FASTEST MILE FOR YESTERDAY..................15 S AT 3:43 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE...............15 S AT 3:43 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..............15 SSE AT 12:23 P.M. AVERAGE WIND SPEED AND DIRECTION...........7.7 S ASOS....................8.0 DAVIS...................6.9 S [188 deg.] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.10 DEPARTURE............-0.05 ASOS..............0.10 TOTAL PRECIPITATION FOR THE MONTH..........3.09 DEPARTURE............-0.62 ASOS..............3.05 TOTAL PRECIPITATION FOR THE YEAR..........35.29 DEPARTURE............+4.61 ASOS..............N/A* *ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals PRELIMINARY CLIMATE SUMMARY FOR JULY 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 7/1 82/69/76/+6/0.05/247/27 29 S AERO 31 MPH SSW RMY 32 7/2 82/61/72/+2/T/100/11 23 SSW AERO 23 MPH SSW RMY 25 7/3 87/62/75/+4/T/556/61 28 SW AERO 30 MPH SW RMY 30 7/4 90/71/81/+10/0.00/811/89 25 WSW AERO 26 MPH SW RMY 28 7/5 92/73/83/+12/0.00/874/96 24 W AERO 25 MPH WSW RMY 25 7/6 90/73/82/+11/0.00/836/92 25 WNW AERO 25 MPH WNW RMY 26 7/7 91/72/82/+11/0.21/508/56 38 SSW AERO 43 MPH SSW RMY 44 TSTM 7/8 82/64/73/+1/0.04/617/68 18 NE AERO 20 MPH NE RMY 20 TSTM 7/9 72/63/68/-4/0.01/054/06 14 ENE AERO 14 MPH ENE RMY 14 7/10 84/65/75/+3/T/335/37 32 S AERO 36 MPH S RMY 35 7/11 79/69/74/+2/0.62/009/01 23 W AERO 23 MPH W RMY N/A TSTM 7/12 70/62/66/-6/0.00/162/18 29 NE AERO 29 MPH NE RMY 30 7/13 75/62/69/-3/0.08/009/01 21 ENE AERO 20 MPH ENE RMY N/A 7/14 89/71/80/+8/0.00/477/53 16 W AERO 16 MPH W RMY 16 7/15 91/72/82/+10/0.00/665/74 17 NW AERO 16 MPH NW RMY 18 7/16 91/71/81/+9/0.00/843/94 18 NNW AERO 16 MPH NNW RMY 16 7/17 93/74/84/+12/0.00/841/94 22 SW AERO 23 MPH SW RMY 25 7/18 90/75/83/+11/0.00/724/81 20 S AERO 21 MPH S RMY 22 7/19 95/76/86/+14/0.00/723/81 36 WSW AERO 38 MPH WSW RMY 38 7/20 93/72/82/+10/0.00/570/64 29 W AERO 30 MPH W RMY 31 TSTM 7/21 82/68/75/+3/0.00/568/64 16 NE AERO 16 MPH NE RMY 17 7/22 80/67/74/+2/T/514/58 17 NE AERO 17 MPH NE RMY 19 7/23 82/68/75/+3/0.82/159/18 35 WSW AERO 36 MPH WSW RMY 39 TSTM 7/24 84/64/74/+2/0.00/627/71 23 N AERO 23 MPH N RMY 23 7/25 64/57/61/-11/0.43/000/00 24 NNE AERO 24 MPH NNE RMY 25 7/26 67/59/63/-9/0.70/000/00 23 NNW AERO 23 MPH N RMY 23 7/27 82/60/71/-1/0.00/535/61 22 S AERO 23 MPH S RMY 23 7/28 78/66/72/0/0.03/149/17 16 ENE AERO 16 MPH ENE RMY 15 7/29 81/66/74/+2/0.10/.../.. 20 S AERO 18 MPH S RMY 21 TSTM 7/30 morning low temp: 61F; the normal low is now 63F DAILY RECORDS FOR JULY 2013 7/14 - TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 71F; ties previous record of 71F set in 1997 7/15 - NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 72F; surpasses previous record of 70F set in 1901, 1934, 1995 7/16 - TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 71F; ties previous record of 71F set in 1901, 1958, 1968 7/17 - TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 74F; ties previous record of 74F set in 1900 7/18 - NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 75F; surpasses previous record of 73F set in 1900, 1999 7/19 - NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 76F; surpasses previous record of 72F set in 1949, 1991, 2005 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR JULY 30 HIGH 99F IN 1949 LOW 51F IN 1956 PRECIP 1.84 INCHES IN 1976 PEAK GUST 70e MPH SW 1944 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 TODAY'S REPORT PREPARED BY: Sean Fankhauser