BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY WEDNESDAY, SEPTEMBER 23, 2015  ALL TIMES ARE IN EASTERN STANDARD TIME   OVERNIGHT TEMPS DIP TO 50F DURING ARRIVAL OF FALL  **BLUE HILL OBSERVATORY KICKSTARTER CAMPAIGN NEARLY  HALFWAY TO RAISING FUNDS TO REPLACE OUR BELFORT AEROVANE ANEMOMETER. PLEASE MAKE A TAX-DEDUCTIBLE DONATION TODAY SO WE CAN MAKE THIS CRITICAL INSTRUMENT PURCHASE:** https://www.kickstarter.com/projects/1451380431/fund-the-future-of-climate-science-at-blue-hill-ob The autumnal equinox arrived at 4:21 AM EDT this morning, and with it, tying the coolest temperatures we have seen so far this month, with an overnight low of 50F. Skies were mostly this morning as well, with visibility observed at a rare station maximum of 90 miles during this morning's 7:00 AM EST. By the 1:00 PM EST observation skies had remained mostly clear with only a few small cumulus and cirrus distant to mostly our SE. Temperatures had climbed to a maximum of 71F while dew points had dropped into the lowers 40s. Relatively humidity reflected this large spread at 34 percent. Visibility was 80 miles in all directions.   Today's Observations: 7 A.M. Weather: Clear, few cumulus distant offshore ENE-S, few cirrus distant E-SW Temperature: 53F; Dew Point: 51F; Wind: N at 9 kts, Sea-level pressure: 30.27 ins. Hg, rising slightly Visibility: 35 miles, except 90 miles WSW-N, thin fog NNE-SW  6-hr Max temp: 54F   6-hr Min temp: 50F 24-hr precip: none BHO SA 1155 CLR 35 252/53/51/3609/027/ VSBY WSW-N 90 MI FEW CU DSNT OFFSHR ENE-S FEW CI DSNT E-SW THN FG DSNT NNE-SW/ 8/101 50002 10054 20050  10 A.M. Weather: Clear, few cumulus distant ESE-SSE, few cirrus distant ENE-SW Temperature: 67F; Dew Point 45F; Wind: estimated ENE at 5 kts, Wind Speed: Light  Sea-level pressure: 30.29 ins. Hg, rising, then falling but higher still  Visibility: 80 miles BHO SA 1455 CLR 80 257/67/45/E0705/029/ FEW CU DSNT ESE-SSE FEW CI DSNT ENE-SW WND LGT/ 8/101 50005 1 P.M. Weather: Clear, few small cumulus distant ESE-SSE, few cirrus distant ENE-SSW         Temperature: 71F; Dew Point: 42F; Wind: estimated NE 4 kts Wind Speed and Direction: Light and Variable Sea-level pressure: 30.26 ins. Hg, falling, then more slowly  Visibility: 80 miles 6-hr Max: 71F  6-hr Min: 53F BHO SA 1755 CLR 80 248/71/42/E0504/026/ FEW SML CU DSNT ESE-SSE FEW CI DSNT ENE-SSW WND LGT AND VRB/ 8/101 56009 10071 20053   SUMMARY FOR TUESDAY, SEPTEMBER 22, 2015     TEMPERATURE (DEGREES F) MAX.....67   NORMAL.....69  MIN.....55   NORMAL.....52  MEAN....61   NORMAL.....61    DEPARTURE FROM 30-YEAR NORMAL........................+0 TOTAL DEPARTURE FOR THE MONTH......................+123  [+5.4 DEGREES/DAY]   COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY...............0   DEPARTURE..........-1 TOTAL COOLING UNITS FOR THE MONTH.............131   DEPARTURE.........+78 TOTAL COOLING UNITS FOR THE SEASON............797   DEPARTURE........+207 TOTAL COOLING UNITS LAST SEASON TO DATE.......571   DIFFERENCE.......+226 HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY...............4   DEPARTURE..........-1 TOTAL HEATING UNITS FOR THE MONTH..............16   DEPARTURE.........-46 TOTAL HEATING UNITS FOR THE SEASON.............17   DEPARTURE.........-70 TOTAL HEATING UNITS LAST SEASON TO DATE........68   DIFFERENCE........-51   PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...................21  E   AT  1:36 P.M.                       ASOS........................22  ENE AT  1:19 P.M.                         DAVIS.......................20  E   AT  1:18 P.M. RMY 21 FASTEST MILE FOR YESTERDAY.....................13  E   AT  1:18 P.M.    MAXIMUM 2-MINUTE ASOS AVERAGE..................15  ENE AT  1:34 P.M.      MAXIMUM 2-MINUTE DAVIS AVERAGE.................14  E   AT  1:20 P.M.      AVERAGE WIND SPEED AND DIRECTION..............9.3 ENE                     ASOS.......................9.5                      DAVIS......................8.5 ENE [058 DEG]  PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.....0.00  DEPARTURE.....-0.15                          ASOS...............0.00 TOTAL PRECIPITATION FOR THE MONTH...........1.35  DEPARTURE.....-1.53                          ASOS...............1.33 TOTAL PRECIPITATION FOR THE YEAR...........31.60  DEPARTURE.....-6.29                          ASOS................N/A *** *** ASOS annual total not available due to erroneous readings PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY GUST RMY:  R.M. Young wind gust recording system TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized 9/1  81/65/73/+5/0.00/766/97               20 SSW RMY 20 9/2  89/64/77/+9/0.00/732/93               20 SW  RMY 21   9/3  85/66/76/+9/T/612/78                  17 E   RMY N/A TSTM  9/4  72/58/65/0/0.00/297/38                31 ENE RMY N/A 9/5  77/55/66/-1/0.00/748/96               14 SW  RMY 18 9/6  87/57/72/+5/0.00/753/97               21 SSW RMY 22 9/7  92/63/78/+12/0.00/727/94              23 WSW RMY 24 9/8  97/70/84/+18/0.00/693/90              22 WSW RMY 24 9/9  92/70/81/+15/0.00/683/89              30 SSW RMY 33 9/10 73/62/68/+3/..../000/00               29 NE  RMY N/A 9/11 70/59/65/0/..../084/11                33 NE  RMY N/A 9/12 75/58/67/2/..../380/50                18 SSE RMY 25  9/13 66/60/63/-1/..../000/00               25 E   RMY N/A 9/14 70/53/62/-2/0.00/550/73               33 W   RMY 35 9/15 82/56/69/+5/0.00/736/98               23 W   RMY N/A 9/16 84/62/73/+10/0.00/711/95              17 NW  RMY N/A 9/17 87/64/76/+13/0.00/723/97              17 SW  RMY 16 9/18 86/64/75/+13/0.00/712/96              21 SSW RMY 21 9/19 80/62/71/+9/0.00/.../..               22 S   RMY N/A 9/20 74/55/65/+3/T/..../...                24 S   RMY N/A   9/21 65/50/58/-3/0.00/.../..               29 ENE RMY 30 9/22 67/55/61/+0/0.00/.../..               21 E   RMY 21 9/23 low since midnight is 50F; normal low is now 52F   DAILY RECORDS FOR SEPTEMBER 2015 **9/7 DAILY RECORD MAXIMUM TEMPERATURE OF 92F  TIES PREVIOUS RECORD SET IN 2007** **9/8 DAILY RECORD MAXIMUM TEMPERATURE OF 97F BREAKS PREVIOUS RECORD OF 93F SET IN 2007** **9/8 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F BREAKS PREVIOUS RECORD OF 69F SET IN 1999** **9/9 DAILY RECORD MAXIMUM TEMPERATURE OF 92F BREAKS PREVIOUS RECORD OF 91F SET IN 2002** **9/9 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F BREAKS PREVIOUS RECORD OF 69F SET IN 1999** **9/17 DAILY RECORD MAXIMUM TEMPERATURE OF 87F BREAKS PREVIOUS RECORD OF 86F SET IN 1915, 1941, AND 1991** **9/18 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 64F TIES PREVIOUS RECORD SET IN 1992** DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated):  RECORDS FOR SEPTEMBER 23 HIGH 93F IN 1895,1914 LOW 33F IN 1904 PRECIP 2.67 INCHES IN 1994 PEAK GUST 62 MPH SSW IN 1989 RECORDS FOR SEPTEMBER 24 HIGH 87F IN 1959 LOW 33F IN 1885,1950,1963 PRECIP 1.19 INCHES IN 1955 PEAK GUST 54e MPH SW IN 1940 TODAY'S REPORT PREPARED BY: Brian Fitzgerald