BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, APRIL 13, 2010 ALL TIMES ARE IN EASTERN STANDARD TIME TEMPERATURES DROP TO UPPER 30'S ON SUMMIT COLDEST TEMPS. OF MONTH TO DATE AT LOWEST ELEVATIONS The lowest temperature dropped below 40 degrees for only the 3rd time this month with a low of 39F. Lower elevations had lows of freezing and below with a light frost. A dense layer of high cirrus and cirrostratus cloudiness overspread the region this morning but was thinning and clearing away by this afternoon allowing more and more bright sunshine. High temperatures were being held to the mid-50's and quite a bit cooler than yesterday's high of 61F. Today's observations: 7 A.M. Weather: Scattered cirrus and cirrostratus layer, thin broken cirrus and cirrostratus layer slowly invading the sky, break in overcast is a clear band distant north thru northeast Temperature: 46F, Dew point: 26F, Wind: NNW at 2 kts (estimated) Sea-level pressure: 30.48 inches Hg, rising Visibility: 60 miles, thin smoke layer along horizon NNW-NE T 6-hour minimum temp: 39F 24-hour precipitation: 0.00 inches BHO SA 1155 250 SCT 300 –BKN 60 322/46/26/E3402/048/ BINOVC/CLR SKY DSNT N-NE THN K LYR ALG HRZN NNW-NE/ 8/006 52017 10046 20039 10 A.M. Weather: Broken dense cirrostratus layer, overcast layer higher cirrus and cirrostratus, cumulus forming west thru north, breaks in overcast and overcast partly thin to the northwest thru the northeast, solar halo Temperature: 49F, Dew point: 28F, Wind: NE at 7 kts, Wind: Direction variability north to east-northeast Sea-level pressure: 30.52 inches Hg, rising Visibility: 70 miles BHO SA 1455 E220 BKN 250 OVC 70 335/49/28/0407/052/ CU FRMG W-N-E BINOVC/OVC PTLY THN NW-NE HALO WND 35V07/ 8/107 51013 1 P.M. Weather: Scattered dense cirrostratus layer southeast thru southwest, thin broken layer cirrus, cumulus few moderate except overhead and northeast thru east Temperature: 52F, Dew point: 30F, Wind: NNE at 7 kts, Wind: Direction variable northwest to east-northeast Sea-level pressure: 30.49 inches Hg, falling Visibility: 70 miles 6-hour maximum temp: 55F BHO SA 1755 220 SCT 250 –BKN 70 325/52/30/0207/049/ CU/FEW MDT XCPT OVHD-NE-E DENS CS LYR SE-SW WND 32V07/ 8/208 58010 10055 20046 WEATHER SUMMARY FOR MONDAY, APRIL 12 TEMPERATURE (DEGREES F) MAX.....61 NORMAL.....54 MIN.....43 NORMAL.....36 MEAN....52 NORMAL.....45 DEPARTURE FROM 30-YEAR AVERAGE................+7 TOTAL DEPARTURE FOR THE MONTH...............+160 (+13.1 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............13 DEPARTURE........-7 TOTAL HEATING UNITS FOR THE MONTH...........105 DEPARTURE......-157 TOTAL HEATING UNITS FOR THE SEASON.........5201 DEPARTURE......-525 TOTAL HEATING UNITS LAST SEASON TO DATE....5666 DIFFERENCE.....-465 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY.............31 W AT 1:39 P.M. AEROVANE..............33 W AT 1:38 P.M. ASOS..................31 W AT 1:40 P.M. DAVIS.................32 W AT 1:39 P.M. THE FASTEST MILE FOR YESTERDAY...........20 WNW AT 1:57 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE............20 WNW AT 1:59 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE...........22 WNW AT 1:59 P.M. AVERAGE WIND SPEED AND DIRECTION..........9.3 W ASOS.................. 8.7 DAVIS.................10.0 NW {310 DEG] * last of several occurrences... 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..........1.12 DEPARTURE......-0.68 ASOS..............1.10 TOTAL PRECIPITATION FOR THE YEAR..........29.03 DEPARTURE.....+13.60 ASOS.............29.20 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE......-0.1 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE......-1.3 TOTAL SNOWFALL FOR THE SEASON..............64.4 DEPARTURE......+6.2 PRELIMINARY CLIMATE SUMMARY FOR APRIL 2010 CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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 4/1 59/43/51/+10/T/0/359/47 24 NNW AERO 30 MPH NNW 4/2 67/46/57/+15/0.00/0/728/95 21 SSE 4/3 75/45/60/+18/0.00/0/731/95 26 SSE 4/4 76/45/61/+19/0.00/0/617/80 27 W AERO 29 MPH W 4/5 72/53/63/+20/0.00/0/635/82 37 SSE AERO 40 MPH SSE 4/6 68/50/59/+16/T/0/202/26 23 W 4/7 90/45/68/+25/0.00/0/.../.. 36 WSW AERO 41 MPH WSW 4/8 65/45/55/+11/.../0/.../.. 31 ENE 4/9 56/37/47/+3/1.12/0/.../.. 35 W AERO 39 MPH W 4/10 56/37/47/+3/0.00/0/.../.. 45 W AERO 52 MPH W 4/11 69/47/58/+13/0.00/0/.../.. 36 W AERO 40 MPH W 4/12 61/43/52/+7/0.00/0/.../.. 31 W AERO 33 MPH W Our morning low temp: 39F; the normal low temp: is now 36F NEW DAILY RECORDS FOR APRIL 2010 4/4 - new record high maximum temperature of 76F; surpasses 71F in 1950. 4/5 - new record high minimum temperature of 53F; surpasses 52F in 1981 4/7 - new record high maximum temperature of 90F; surpasses 86F in 1929 DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 13 HIGH 85 IN 1945 LOW 22 IN 1939 PRECIP 2.51 IN. IN 2004 SNOWFALL 6.8 IN. IN 1933 PEAK GUST 59 MPH SSW IN 1995 RECORDS FOR APRIL 14 HIGH 80 IN 1945 LOW 21 IN 1923 PRECIP 2.22 IN. IN 1895 SNOWFALL 8.4 IN. IN 1953 PEAK GUST 71e MPH W IN 1943 TODAY'S REPORT PREPARED BY: Robert Skilling/Sean Fankhauser