BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, OCTOBER 15, 2009 ALL TIMES ARE IN EASTERN STANDARD TIME FREEZING TEMPERATURES OVERNIGHT FOR SECOND CONSECUTIVE DAY AND POSSIBLE RECORD LOW MAXIMUM TEMPERATURE TODAY Our morning low temperature of 32.2F in the Hazen shelter was the second consecutive overnight freeze. Frost was observed at lower elevations, but not on the summit this morning. Yesterday's low of 32F was only four degrees short of the record low temperature for the date, and the low today of 32F was only three degrees short of the record low for today's date of 29F in 1887 and 1937. The temperature so far today has only reached 41F, which will be a record low maximum for the date if it holds through midnight. The previous record low maximum for today's date was 45F in 1962. Today's observations: 7 A.M. Weather: Broken stratocumulus, broken altocumulus, overcast cirrostratus, bright spots in overcast NE-S Temperature: 35F, Dew point: 26F, Wind: NNW at 7 kts Sea-level pressure: 30.16 inches Hg, rising Visibility: 80 miles 6-hour minimum temp: 32F BHO SA 1155 E55 BKN 140 BKN 220 OVC 80 212/35/26/3407/016/ BRGHT SPTS IOVC NE-S THN K LYR SE-S-SW/ 8/577 50004 10035 20032 10 A.M. Weather: Scattered altocumulus, overcast cirrostratus, few stratocumulus NE-SE distant NW-N Temperature: 40F, Dew point: 24F, Wind: NNE at 5 kts, Wind: Light and variable Sea-level pressure: 30.15 inches Hg, falling Visibility: 75 miles BHO SA 1455 120 SCT 200 OVC 75 210/40/24/0205/015/ FEW SC NE-SE AND DSNT NW-N WND LGT AND VRB/ 8/537 58002 1 P.M. Weather: Scattered altocumulus, overcast altostratus, few stratocumulus NE-SE and distant NW, sun dimly visible Temperature: 41F, Dew point: 26F, Wind: NNE at 8 kts, Wind: Direction variable NNW to E Sea-level pressure: 30.09 inches Hg, falling Visibility: 75 miles 6-hour maximum temp: 41F BHO SA 1755 120 SCT E180 OVC 70 191/41/26/0208/009/ FEW SC NE-SE AND DSNT NW SUN DMLY VSBL WND 33V09/ 8/57/ 58019 10041 20035 WEATHER SUMMARY FOR WEDNESDAY, OCTOBER 14 TEMPERATURE (DEGREES F) MAX.....52 NORMAL.....61 MIN.....32 NORMAL.....43 MEAN....42 NORMAL.....52 DEPARTURE FROM 30-YEAR AVERAGE..........-10 TOTAL DEPARTURE FOR THE MONTH...........-32 [-2.5 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............23 DEPARTURE......+10 TOTAL HEATING UNITS FOR THE MONTH...........180 DEPARTURE......+28 TOTAL HEATING UNITS FOR THE SEASON..........337 DEPARTURE......+16 TOTAL HEATING UNITS LAST SEASON TO DATE.....244 DIFFERENCE.....+93 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............27 NW AT 9:17 A.M. AEROVANE..............25 NW AT 9:17 A.M. ASOS..................24 NNW AT 9:17 A.M. DAVIS.................27 WNW AT 9:45 A.M. FASTEST MILE FOR YESTERDAY...............16 WNW AT 9:46 A.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............16 NNW AT 10:18 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........19 WNW AT 10:17 A.M. AVERAGE WIND SPEED AND DIRECTION.......10.1 WNW ASOS................10.4 DAVIS...............10.6 WNW [304 DEG] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE....-0.14 ASOS..............0.00 TOTAL PRECIPITATION FOR MONTH..............2.31 DEPARTURE....+0.35 ASOS..............2.34 TOTAL PRECIPITATION FOR THE YEAR..........40.19 DEPARTURE....+0.63 ASOS.............41.40 PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 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 10/1 56/39/48/-9/0/155/22 27 WSW 10/2 60/40/50/-6/0/442/63 23 SSE 10/3 63/51/57/+1/1.10/000/00 32 ESE AERO 30 MPH ESE 10/4 67/57/62/+6/0/202/29 21 WSW 10/5 64/49/57/+2/0/595/86 33 W AERO 31 MPH W 10/6 65/45/55/0/0/628/91 25 W 10/7 67/51/59/+4/0.70/344/50 54 W AERO 54 MPH W 10/8 61/48/55/+1/0/602/88 43 W AERO 39 MPH W 10/9 60/48/54/0/0.05/000/00 29 SSE 10/10 62/42/52/-2/0.26/205/30 37 NW 10/11 61/39/50/-3/0/655/97 35 WSW AERO 33 MPH W 10/12 53/36/45/-8/T/471/70 23 SSW 10/13 51/36/44/-8/0.20/074/11 35 WNW 10/14 52/32/42/-10/0/.../.. 27 NW 10/15 our morning low temp: 32F; our normal low temp: 43F NEW DAILY RECORDS FOR OCTOBER 2009 10/7: NEW RECORD WIND GUST 54 MPH W AT 2005E; surpasses previous record of 52 MPH ESE in 1972 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR OCTOBER 15 HIGH 83F IN 1897 LOW 29F IN 1887,1937 PRECIP 4.58 INCHES IN 2005 SNOWFALL TRACE IN 1961,1972 PEAK GUST 69 MPH W IN 2003 RECORDS FOR OCTOBER 16 HIGH 86 IN 1897 LOW 28 IN 1886 PRECIP 2.82 INCHES IN 1974 SNOWFALL (NONE) PEAK GUST 68e MPH SSE IN 1954 (HURRICANE HAZEL) TODAY'S REPORT PREPARED BY: Stephanie Radner