BLUE HILL OBSERVATORY MILTON, MA MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA   DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, OCTOBER 21, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME   ZERO VISIBILITY IN DENSE FOG EARLY THIS MORNING  SHOWERS ARRIVE DURING NOON HOUR WITH LIGHT RAINFALL   Visibility was down to zero between 7 and 8 A.M. EDT this morning but rose quickly once the low stratus clouds lifted during the next hour. A few breaks in the overcast and a brief glimpse of sunshine was observed before heavy clouds arrived during the hour before noon EDT.   Showers arrived from the west by noontime. The rainfall amount was small here (0.07 inch) but downpours were reported in the area. Our Hingham weather station had one of those down- pours with a tenth of an inch of rain falling in about 5 minutes.  Thunderstorms occurred well to our southwest through southeast.    Today's observations:    7 A.M. Weather: Obscurement with heavy fog, sun disc visible Temperature: 45F, Dew point: 45F; Wind: SSE at 13 kts Sea-level pressure: 29.64 inches Hg, falling  Visibility: 1/16 mile, increasing, zero past hour 6-hour minimum temp: 44F BHO SA 1155 W2 X 1/16F 036/45/45/1613/964/ VSBY INCR ZERO PST HR SUN DISC VSB/ 8//// 56012 10048 20044    10 A.M. Weather: Scattered altocumulus, layer increasing, high dense cirrostratus overcast, dark sky WSW-NNW, few small breaks and thin spots in overcast distant ESE-S     Temperature: 55F, Dew point: 48F; Wind: S at 13 kts, Wind: Gust to 24 kts past hour, Wind: Direction variable SE to SSW  Sea-level pressure: 29.57 inches Hg, falling Visibility: 12 miles, 8 miles W-NW hazy all quadrants  BHO SA 1455 80 SCT E220 OVC 12 015/55/48/1713/957/ FEW SC ALQDS AC LYR SW-NW INCR DRK WSW-NNW SML BINOVC THN SPTS IOVC DSNT ESE-S VSBY W-NW 8 HAZY ALQDS WND 14V21 GST TO 24 KTS PST HR/ 8/557 58021    1 P.M.  Weather: Scattered stratocumulus, scattered cumulonimbus, overcast altocumulus, cumulonimbus distant E-SE moving east-northeast, bright spots in overcast, light rain was occurring, precipitation very light Temperature: 52F, Dew point: 49F; Wind: SSW at 13 kts. Wind: Direction variable S to WSW Sea-level pressure: 29.51 inches Hg, falling Visibility: 20 miles, except 15 miles northeast, 8 miles to the southeast      6-hour max. temp: 56F  6-hourly precip: 0.07 in.  BHO SA 1755 32 SCT E55 BKN 65 OVC 20R- 992/52/49/2113/951/ CBS DSNT E-SE MOVG ENE BRGHT SPTS IOVC VSBY NE 15 SE 8 PCPN VRY LGT WND 18V24/ 8/37/ 58023 MANUAL 6007/ AS0S 60007 10056 20045   WEATHER SUMMARY FOR WEDNESDAY, OCTOBER 20   TEMPERATURE (DEGREES F) MAX.....61     NORMAL.....59 MIN.....44     NORMAL.....42 MEAN....53     NORMAL.....50   DEPARTURE FROM 30-YEAR NORMAL..............+3 TOTAL DEPARTURE FOR THE MONTH.............-14 [-0.9 DEGREE/DAY]   HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............12    DEPARTURE........-3 TOTAL HEATING UNITS FOR THE MONTH...........249    DEPARTURE.......+12 TOTAL HEATING UNITS FOR THE SEASON..........328    DEPARTURE.......-78 TOTAL HEATING UNITS LAST SEASON TO DATE.....478    DIFFERENCE.....-150   PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............21 S   AT 12:56 P.M.                     AEROVANE..............23 S   AT 12:56 P.M.                    ASOS..................21 S   AT 12:56 P.M.                      DAVIS.................20 S   AT 12:53 P.M.   THE FASTEST MILE FOR YESTERDAY...........16 S   AT 12:55 P.M.  MAXIMUM 2-MINUTE ASOS AVERAGE............17 S   AT 12:57 P.M.   MAXIMUM 2-MINUTE DAVIS AVERAGE...........16 S   AT 12:54 P.M.  AVERAGE WIND SPEED AND DIRECTION....... 9.8 SSW                     ASOS.................9.9                    DAVIS............... 8.9 S [190 DEG]   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 THE MONTH..........5.50  DEPARTURE........+2.70                          ASOS..............5.53 TOTAL PRECIPITATION FOR THE YEAR..........53.52  DEPARTURE.......+13.12                          ASOS.............53.37** ** ASOS missing rainfall due to system failure on 6/24-25   PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 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   10/1  80/55/68/+11/0.56/035/05  55 SSE  AERO 63 MPH SSE 10/2  65/46/56/0/0.00/688/98    28 WNW  AERO 31 MPH WNW 10/3  55/43/49/-7/T/133/19      35 NNE  AERO 39 MPH NNE 10/4  54/48/51/-5/0.78/000/00   39 NNE  AERO 43 MPH NNE 10/5  57/51/54/-1/0.40/000/00   37 NE   AERO 39 MPH NNE 10/6  57/49/53/-2/1.63/000/00   47 NE   AERO 51 MPH NE 10/7  62/47/55/0/0.00/275/40    37 W    AERO 40 MPH W 10/8  70/47/59/+5/0.00/610/89   35 WSW  AERO 37 MPH WSW 10/9  62/43/53/-1/0.00/675/99   33 WNW  AERO 37 MPH WNW 10/10 64/38/51/-3/0.00/679/100  25 SW   AERO 29 MPH SSW 10/11 68/47/58/+5/0.00/542/80   28 W    10/12 61/43/52/-1/0.01/297/44   24 ENE 10/13 61/38/50/-2/0.00/663/99   18 NW 10/14 59/45/52/0/0.41/294/44    29 ENE 10/15 51/39/45/-7/1.71/033/05   48 WSW  AERO 50 MPH WSW TSTM * 10/16 55/39/47/-4/0.00/544/82   47 WNW  AERO 54 MPH WNW 10/17 63/38/51/0/0.00/581/88    43 W    AERO 47 MPH W 10/18 57/41/49/-2/0.00/519/79   32 W    AERO 35 MPH W 10/19 57/38/48/-3/0.00/497/76   21 W  10/20 61/44/53/+3/T/.../..      21 S   10/21 our morning low temp: 44F; the normal low is now 41F   NEW DAILY RECORDS FOR OCTOBER 2010 None so far.   DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated):    RECORDS FOR OCTOBER 21 HIGH 79 IN 1979 LOW 24 IN 1974 PRECIP 2.39 INCHES IN 1944 SNOWFALL TRACE IN 1895,1907,1940 PEAK GUST 69e MPH S IN 1976   RECORDS FOR OCTOBER 22 HIGH 85 IN 1979 LOW 22 IN 1940 PRECIP 1.37 INCHES IN 1898 SNOWFALL TRACE IN 1969 PEAK GUST 67 MPH ESE IN 1988   TODAY'S REPORT PREPARED BY: Robert Skilling