BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, APRIL 15, 2013 PATRIOTS DAY, MARATHON MONDAY ALL TIMES ARE IN EASTERN STANDARD TIME HIGH CLOUDINESS DIMS SUNSHINE BUT TEMPS. NEAR NORMAL APRIL TEMPERATURES RUNNING SLIGHTLY ABOVE NORMAL MONTH CONTINUES TO RUN BELOW NORMAL IN PRECIPITATION The sky has remained covered by cirrostratus clouds during today and part of the layer is opaque; little blue sky has been visible. Despite the dimmed sunshine and light northeast winds our afternoon high temperature has risen to near normal at 55F. The cooler than normal temperatures have lowered the monthly average to less than one degree on the warm side of normal. April continues to be a drier than normal month and as of mid-month we're closing in on an inch and a half drier than normal. Today's observations: 7 A.M. Weather: High overcast cirrostratus, thn spots in the overcast overhead thru NW-NE, clear sky band distant NNW-NE, break in overcast distant NNW-NE, few altocumulus distant WNW Temperature: 41F; Dew Point: 29F; Wind: NE at 6 kts Sea-level pressure: 30.35 ins. Hg, rising then more rapidly Visibility: 70 miles, light distant haze 6-hour min. temp: 35F BHO SA 1155 E250 OVC 70 279/41/29/0406/035/ FEW AC DSNT WNW BINOVC AND CLR SKY BND DSNT NNW-NE OVC PTLY THN OVHD-NW-NE THN K LYR ALG HRZN DSNT SSE-SSW AND ALG HRZN DSNT NNW-NE LGT DSNT HZ INVSN DSSPTNG/ 8/047 53029 10041 20035 10 A.M. Weather: Scattered altocumulus [2 layers], lower layer duplicatus, broken cirrus, cirrostratus, [2 layers, partly thin], patch of clear sky NE, few small cumulus forming distant NNW-NNE Temperature: 48F; Dew Point: 29F; Wind: ESE at 4 kts, Wind: Light Sea-level pressure: 30.39 ins. Hg, rising steady then rising Visibility: 60 miles, NW 70 miles, ENE 25 miles, light distant haze BHO SA 1455 130 SCT 150 SCT 250 BKN 300 BKN 60 291/48/29/1204/039/ FEW SML CU FRMG DSNT NNW-NNE PTCH CLR SKY NE 250/300 LYRS PTLY THN VSBY ENE 25 NW 70 LGT DSNT HZ WND LGT/ 8/178 51012 1 P.M. Weather: Scattered dense cirrostratus layer, overcast cirrostratus, few small cumulus mostly distant SE-S, few altocumulus lenticularis E-S-NW, dense cirrostratus layer E-S-W, overcast partly thin overhead thru NW-NE, solar halo Temperature: 53F; Dew Point: 33F; Wind: ENE at 8 kts, Wind: Direction variable N-E Sea-level pressure: 30.36 ins. Hg, falling then more slowly Visibility: 60 miles, except 70 NW and lower NE-SE, light distant haze 6-hour max temp: 55F BHO SA 1755 220 SCT E250 OVC 60 280/53/33/0608/036/ FEW SML CU MSTLY DSNT SE-S FEW ACSL E-S-WNW DNS CS LYR E-S-W OVC PTLY THN OVHD-NW-NE SOLAR HALO VSBY NW 70 LWR NE-SE LGT DSNT HZ WND 01V10/ 8/147 56011 10055 20041 WEATHER SUMMARY FOR SUNDAY, APRIL 14 TEMPERATURE (DEGREES F) MAX.....52 NORMAL.....55 MIN.....36 NORMAL.....37 MEAN....44 NORMAL.....46 DEPARTURE FROM 30-YEAR NORMAL....................-2 TOTAL DEPARTURE FOR THE MONTH...................+12 [+0.7 DEGREE/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............21 DEPARTURE..........+2 TOTAL HEATING UNITS FOR THE MONTH...........289 DEPARTURE.........-11 TOTAL HEATING UNITS FOR THE SEASON.........5309 DEPARTURE........-475 TOTAL HEATING UNITS LAST SEASON TO DATE....4542 DIFFERENCE.......+767 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............31 WNW AT 4:43 P.M. * AERO....................27 WNW AT 4:43 P.M. * ASOS....................31 WNW AT 4:44 P.M. DAVIS...................30 WNW AT 4:41 P.M. RMY: 32 THE FASTEST MILE FOR YESTERDAY.............23 WNW AT 4:43 P.M. * MAXIMUM 2-MINUTE ASOS AVERAGE..............22 WNW AT 4:43 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............21 WNW AT 4:40 P.M. AVERAGE WIND SPEED AND DIRECTION.........10.8 WNW ASOS..................10.3 DAVIS..................9.6 WNW [290 deg] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00 DEPARTURE...........-0.16 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.18 DEPARTURE...........-1.18 ASOS..............1.13 TOTAL PRECIPITATION FOR THE YEAR..........15.27 DEPARTURE...........-1.09 ASOS..............N/A* *ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M...........0 DEPARTURE............-0.1 TOTAL SNOWFALL FOR THE MONTH..............trace DEPARTURE............-2.1 TOTAL SNOWFALL FOR THE SEASON.............99.0 DEPARTURE...........+37.2 PRELIMINARY CLIMATE SUMMARY FOR APRIL 2013 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 4/1 61/31/46/+5/0.34/0.0/458/60 40 W AERO 44 MPH WNW RMY 46 TSTM 4/2 40/27/34/-7/T/T/460/60 45 W AERO 42 MPH W RMY 47 4/3 45/27/36/-6/0.00/0.0/755/98 44 W AERO 43 MPH W RMY 47 4/4 55/26/41/-1/0.00/0.0/719/93 30 WSW AERO 27 MPH WSW RMY 31 4/5 59/36/48/+5/0.00/0.0/403/52 33 NNW AERO 28 MPH NNW RMY 38 4/6 47/30/39/-4/0.00/0.0/747/96 38 NW AERO 35 MPH NW RMY 40 4/7 52/31/42/-1/0.00/0.0/391/50 51 S AERO 46 MPH S RMY 50 4/8 65/43/54/+10/T/0.0/494/63 29 SSW AERO 22 MPH SSW RMY N/A 4/9 72/44/58/+14/T/0.0/456/58 35 WNW AERO 35 MPH WNW RMY 39 TSTM 4/10 64/43/54/+9/0.13/0.0/426/54 23 SE AERO 20 MPH SE RMY 25 4/11 52/40/46/+1/0.09/0.0/.../.. 18 ENE AERO 14 MPH ENE RMY N/A 4/12 40/34/37/-8/..../T/.../.. 38 E AERO 32 MPH E RMY 41 4/13 52/34/43/-3/..../0.0/.../.. 31 NNE AERO 27 MPH NNE RMY 21 4/14 52/36/44/-2/0.00/0.0/.../.. 31 WNW AERO 27 MPH WNW RMY 32 4/15 the morning low temp: 35F; the normal low is now 38F DAILY RECORDS FOR APRIL 2013 None so far. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR APRIL 15 HIGH 81 IN 1896 LOW 23 IN 1943 PRECIP 1.75 IN. IN 2007 SNOWFALL 1.0 IN. IN 1916, 1962 PEAK GUST 66 MPH E IN 2007 RECORDS FOR APRIL 16 HIGH 89 IN 2012 LOW 23 IN 1943 PRECIP 2.45 IN. IN 1929 SNOWFALL 2.0 IN. IN 1904, 1962 PEAK GUST 73 MPH E IN 2007 TODAY'S REPORT PREPARED BY: Robert Skilling