BLUE HILL OBSERVATORY MILTON, MA MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, SEPTEMBER 25, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME SULTRY SUMMER CONDITIONS CONTINUE... Summer just doesn't want to fade away. The past two days of warmth and humidity have felt more like mid-summer days. Friday's high of 81F was 13 degrees above average, and the average temperature for the day was 11 degrees above average. Southerly winds continue to transport warm, humid air into the region today. The temperature has already reached 81F as of 10:00 AM EST. The overnight low only reached 67F! That's 17 degrees above average, and very close to the average high for the date! Dew points are quite high, and continuing in the upper 60s today. The added moisture in the air is restricting visibility to about 10-15 miles today. Rain is needed. Rainfall for the month of September is now more than 2 inches below average. In the 31 days (including today) since our big August storm that brought 7.47 inches of rain, we've only received 1.08 inches of rain. We've had only 25% of our normal rainfall over the past 31 days. Today's observations: 7 A.M. Weather: Broken altocumulus, few altocumulus lenticularus southeast thru south and northwest, few altocumulus castellanus west-southwest thru west-northwest, thin fog and haze Temperature: 71F, Dew point: 67F; Wind: S at 14 kts Sea-level pressure: 29.77 inches Hg, falling slightly Visibility: 8 miles, thin fog and haze 6-hour minimum temp: 67F BHO SA 1155 E120 BKN 8 081/71/67/1914/977/ FEW ACSL SE-S AND NW FEW ACC WSW-WNW THN FG HAZY/ 8/080 56003 10071 20067 10 A.M. Weather: Scattered altocumulus, few altocumulus lenticularus distant north-northeast thru southeast and southwest, few altocumulus castellanus east and south-southwest thru west thru north-northwest, hazy Temperature: 81F, Dew point: 68F; Wind: SSW at 11 kts, Wind: Direction variable S to W Sea-level pressure: 29.78 inches Hg, rising slightly Visibility: 15 miles, hazy BHO SA 1455 120 SCT 15 083/81/68/2111/978/ FEW ACSL DSNT NNE-SE AND SW FEW ACC E AND SSW-W-NNW HAZY WND 18V27/ 8/080 53002 WEATHER SUMMARY FOR FRIDAY, SEPTEMBER 24 TEMPERATURE (DEGREES F) MAX.....81 NORMAL.....68 MIN.....58 NORMAL.....50 MEAN....70 NORMAL.....59 DEPARTURE FROM 30-YEAR NORMAL.............+11 TOTAL DEPARTURE FOR THE MONTH.............+67 [+2.6 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY.............0 DEPARTURE........-7 TOTAL HEATING UNITS FOR THE MONTH........... 57 DEPARTURE.......-36 TOTAL HEATING UNITS FOR THE SEASON...........70 DEPARTURE.......-54 TOTAL HEATING UNITS LAST SEASON TO DATE.....110 DIFFERENCE......-40 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............29 S AT 10:45 A.M. AEROVANE..............31 S AT 10:43 A.M. * ASOS..................29 SW AT 10:45 A.M. DAVIS.................31 SSW AT 7:58 A.M. THE FASTEST MILE FOR YESTERDAY...........23 S AT 10:46 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............23 SSW AT 10:46 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........25 S AT 10:47 A.M. AVERAGE WIND SPEED AND DIRECTION.......17.0 S ASOS................16.4 DAVIS...............15.0 S [179 DEG] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...Trace DEPARTURE........-0.14 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.08 DEPARTURE........-2.21 ASOS..............1.05 TOTAL PRECIPITATION FOR THE YEAR..........47.11 DEPARTURE.......+10.35 ASOS.............46.89 ** ** 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/+16/0.00/765/97 18 SW 9/2 93/72/83/+17/0.00/740/94 25 SSW 9/3 83/69/76/+10/0.47/039/05 25 NNE 9/4 79/62/71/+5/0.00/672/86 37 WSW AERO 39 MPH WSW 9/5 73/55/64/-1/0.00/778/100 28 SW AERO 32 MPH SW 9/6 76/54/65/0/T/768/99 22 SSW 9/7 84/62/73/+8/0.00/440/57 30 SSW AERO 32 MPH S 9/8 80/59/70/+5/0.08/300/39 35 W AERO 40 MPH W TSTM 9/9 72/55/64/0/T/352/46 28 W 9/10 67/55/61/-3/0.00/260/34 26 WNW 9/11 68/53/61/-3/0.00/723/95 18 NE 9/12 63/54/59/-4/T/045/06 22 ENE AERO 24 MPH NE 9/13 67/54/61/-2/0.02/091/12 22 S 9/14 74/53/64/+1/T/489/65 31 WSW AERO 32 MPH WSW 9/15 67/49/58/-4/0.00/660/88 28 W AERO 31 MPH W 9/16 70/46/58/-4/0.26/530/71 43 S 9/17 68/53/61/-1/0.25/000/00 45 S 9/18 65/53/59/-2/0.00/193/26 15 SE 9/19 76/54/65/+4/T/451/61 17 SW AERO 22 MPH SW 9/20 69/50/60/-1/0.00/707/96 29 NW AERO 33 MPH NW 9/21 70/46/58/-2/0.00/711/97 31 S AERO 35 MPH S 9/22 84/58/71/+11/T/.../.. 32 SSW AERO 36 MPH SSW 9/23 73/58/66/+6/0.00/.../.. 20 SSE 9/24 81/58/70/+11/T/.../.. 29 S 9/25 our overnight low temp: 67F; the normal low is now 50F NEW DAILY RECORDS FOR SEPTEMBER 2010 9/1 - High maximum temperature of 93F equals the previous record of 93F set in 1969 9/1 - High minimum temperature of 73F surpasses the previous record of 71F in 1898, 1959 9/2 - High minimum temperature 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 25 HIGH 87F IN 1970 LOW 31F IN 1950 PRECIP 2.68 INCHES IN 1961 PEAK GUST 63 MPH SSW IN 1991 RECORDS FOR SEPTEMBER 26 HIGH 91F IN 2007 LOW 36F IN 1905,1922,1978 PRECIP 3.84 INCHES IN 1888 PEAK GUST 54e MPH S IN 1977 TODAY'S REPORT PREPARED BY: Sean Fankhauser