BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY THURSDAY, OCTOBER 25, 2012 ALL TIMES ARE IN EASTERN STANDARD TIME CLEAR SKY AND VERY LIGHT WINDS OVERNIGHT INTO THIS MORNING STEEP TEMPERATURE INVERSION DEVELOPS FROM 29F to 46F 24-HOUR WIND AVERAGE AMONG OUR LOWEST ON RECORD NEPONSET VALLEY WATERSHED FEELING DROUGHT EFFECTS Temperatures fell to 29 degrees at Norwood and 30 degrees at Taunton airports early this morning while the low was a relatively mild 46F here at the summit as a steep temperature inversion developed overnight. The 24-hour wind average of only around 3 MPH and recorded at 2.6 MPH on Merlin ending at 7 a.m. EST this morning is likely among our lowest on record for a 24-hour value. The month remains dry with only 37% of our normal rainfall to date. The rainfall deficit for the year has now began to approach 13 inches. The total for 2012 is 70% of normal at 29.91 inches. The Neponset River is running at less than 20% of normal runoff and a well has gone dry at Meditech at the base of Blue Hill. Today's observations: 7 A.M. Weather: Scattered altocumulus, high scattered cirrus, patches altocumulus SSW-N, patches thin cirrus to the north thru ESE Temperature: 50F; Dew Point: 39F; Wind: ENE at 5 kts. Sea-level pressure: 30.28 ins. Hg, rising then more slowly Visibility: 20 miles, thin fog below summit and inversion with few dense patches SE-SW, dissipating, haze 6-hour max. temp. 50F 6-hour min. temp: 46F 24-hour precip: Trace BHO SA 1155 70 SCT 300 SCT 20 254/50/39/0605/028/ PTCHS AC SSW-N PTCHS THN CI N-ESE PTCHY THN FG BLO INVSN BLO SMT FEW DNS PTCHS SE-SW PTCHS THN STEAM FOG OVR PONDS VC SE/ 8/031 51011 10050 20046 10 A.M. Weather: Clear, altocumulus layer extending distant SSW-WNW, few altocumulus lenticularis distant SSE-S, stratocumulus, moderate cumuloform tops offshore distant to the NE Temperature: 58F; Dew Point: 33F; Wind: E at 3 kts, Wind: Light Sea-level pressure: 30.32 ins. Hg, rising then more slowly Visibility: 35 miles, N-NE 20, WNW 45, smoke layer along the horizon WNW-ENE, dark smoke layer along and above horizon over city NNW-N, distant haze BHO SA 1455 CLR 35 266/58/33/0903/032/ AC LYR DSNT SSW-WNW FEW ACSL DSNT SSE-S K LYR ALG HRZN WNW-ENE DRK K LYR HRZN AND ALF OVR CTY NNW-N VSBY N-NE 20 WNW 45 DSNT HZ/ 8/070 51012 1 P.M. Weather: Scattered stratocumulus lenticularis, S-NW, few cumulus NNE, stratocumulus/cumuloform tops distant in the offshore NE-ENE, altocumulus layer distant SSW-W Temperature: 62F; Dew Point: 33F; Wind: ENE at 6 kts, Wind: Light Sea-level pressure: 30.29 ins. Hg, falling then more rapidly Visibility: 50 miles, distant haze, smoke layer aloft NW-N and aloft above horizon NNE-ENE 6-hour max. temp: 62F 6-hour min. temp: 50F BHO SA 1755 38 SCT 90 SCT 50 256/62/33/0706/029/ FEW CU NNE SCSL S-NW AC LYR DSNT SSW-W SC/CUFRM TOPS OFFSHR DSNT NE-ENE THN K LYR NW-N ALF K LYR ALF NNE-ENE DSNT HZ WND LGT/ 8/870 58010 10062 20050 WEATHER SUMMARY FOR WEDNESDAY, OCTOBER 24 TEMPERATURE (DEGREES F) MAX.....53 NORMAL.....58 MIN.....46 NORMAL.....40 MEAN....50 NORMAL.....49 DEPARTURE FROM 30-YEAR NORMAL.....................+1 TOTAL DEPARTURE FOR THE MONTH....................+53 [+2.0 DEGREE/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............15 DEPARTURE........-1 TOTAL HEATING UNITS FOR THE MONTH...........242 DEPARTURE.......-57 TOTAL HEATING UNITS FOR THE SEASON..........341 DEPARTURE......-100 TOTAL HEATING UNITS LAST SEASON TO DATE.....256 DIFFERENCE......+85 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............21 NNE AT 1:27 A.M. * AERO..................20 NNE AT 1:27 A.M. ASOS..................21 NNE AT 1:06 A.M. DAVIS.................18 NE AT 12:47 A.M. RMY N/A THE FASTEST MILE FOR YESTERDAY...........11 NE AT 1:48 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE............14 NE AT 1:28 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........13 NNE AT 1:48 A.M. AVERAGE WIND SPEED AND DIRECTION........4.7 NNE ASOS.................4.3 DAVIS................4.6 NNE [030 deg] * last of several occurrences PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...Trace DEPARTURE...........-0.15 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.29 DEPARTURE...........-2.31 ASOS..............1.23 TOTAL PRECIPITATION FOR THE YEAR..........29.91 DEPARTURE..........-12.77 ASOS.............29.78 PRELIMINARY CLIMATE SUMMARY FOR OCTOBER 2012 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 10/1 66/47/57/0/T/429/61 36 W AERO 35 MPH WSW RMY 36 10/2 69/53/61/+4/0.12/098/14 18 W AERO 16 MPH W RNT 16 10/3 62/58/60/+4/0.02/000/00 20 NE AERO 18 MPH NE RMY 18 10/4 61/58/60/+4/0.08/000/00 17 NNE AERO 14 MPH NE RMY 14 10/5 75/57/66/+10/0.00/623/90 20 SW AERO 19 MPH SW RMY 21 10/6 77/48/63/+8/0.20/269/39 36 SSW AERO 37 MPH SSW RMY 36 TSTM 10/7 57/44/51/-4/0.15/185/27 21 WNW AERO 18 MPH WNW RMY 19 10/8 55/40/48/-6/0.00/328/48 17 WNW AERO 15 MPH WNW RMY N/A 10/9 56/49/53/-1/T/000/00 27 E AERO 25 MPH ENE RMY 25 10/10 60/47/54/0/0.22/000/00 36 WNW AERO 36 MPH WNW RMY 31 10/11 58/41/50/-3/0.00/668/99 35 WNW AERO 33 MPH WNW RMY 34 10/12 51/34/43/-10/0.04/296/44 32 WNW AERO 30 MPH NW RMY 30 10/13 52/29/41/-12/0.00/582/87 22 SSW AERO 20 MPH WNW RMY N/A 10/14 66/43/55/+3/0.09/167/25 40 SW AERO 39 MPH SW RMY 39 10/15 73/58/66/+14/0.03/279/42 43 SSW AERO 43 MPH SSW RMY 43 10/16 61/40/51/0/0.03/522/79 38 WNW AERO 36 MPH WNW RMY 38 10/17 60/35/48/-3/0.00/612/93 22 NW AERO 18 MPH NW RMY N/A 10/18 66/46/56/+5/0.00/636/97 25 ESE AERO 23 MPH ESE RMY 25 10/19 66/51/59/+9/0.20/007/01 39 SSE AERO 38 MPH SSE RMY 39 10/20 73/53/63/+13/0.11/377/58 33 SSW AERO 32 MPH SSW RMY 34 TSTM 10/21 63/45/54/+4/0.00/564/87 36 WNW AERO 32 MPH WNW RMY 34 10/22 65/46/56/+7/0.00/632/98 37 WNW AERO 35 MPH WNW RMY 36 10/23 64/46/55/+6/0.00/398/62 27 NW AERO 24 MPH NW RMY 26 10/24 53/46/50/+1/T/000/00 21 NNE AERO 20 MPH NNE RMY N/A 10/25 our morning low temp: 46F; the normal low is now 40F DAILY RECORDS FOR OCTOBER 2012 10/13 - NEW DAILY RECORD LOW MINIMUM TEMPERATURE OF 29F; surpasses previous record of 30F set in 1934, 1936, 1988 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR OCTOBER 25 HIGH 81F IN 1963 LOW 26F IN 1922,1939 PRECIP 2.45 INCHES IN 2005 SNOWFALL 1.2 INCHES IN 1960 PEAK GUST 72 MPH ESE IN 1980 RECORDS FOR OCTOBER 26 HIGH 80F IN 1963 LOW 24F IN 1933 PRECIP 1.72 INCHES IN 1894 SNOW 3.0 INCHES IN 1962 WIND 59 MPH SSE IN 1967 TODAY'S REPORT PREPARED BY: Robert Skilling