BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY SATURDAY, MARCH 16, 2013 ALL TIMES ARE IN EASTERN STANDARD TIME CHILLY AND PARTLY SUNNY WITH LIGHT WINDS TODAY... The low temperature this morning of 25F was much warmer than the 17F measured on Friday, though this is still colder than average for the middle of March. The high temperature through early afternoon of 35F is well below the average, which is in the mid-40s. There has been some sunshine today, though it has been filtered through high and middle level clouds much of the day. For a couple of hours after sunrise, a pair of optical effects known as perihelia appeared on either side of the sun this morning as the sunlight refracted through the ice crystals in the high clouds. Ponkapoag Pond is getting very close to being thawed with about five percent ice cover remaining along the east and south shores. Today's observations: 7 A.M. Weather: Thin overcast cirrus, few stratocumulus along/offshore distant NE-SE, few cumulus/stratocumulus SSE-S, few lower dense cirrus, perihelia (optical effects on either side of the sun) Temperature: 27F; Dew Point: 14F; Wind: NW at 7 kts Sea-level pressure: 29.84 ins. Hg, rising Visibility: 75 miles 6-hr min. temp: 25F 6-hour precip: Trace 6-hour snowfall: Trace Snow depth: Trace BHO SA 1155 250 –OVC 75 104/27/14/3107/984/ FEW SC ALG/OFFSHR DSNT NE-SE FEW CU/SC SSE-S FEW LWR DNS CI PERIHELIA/ 8/501 51024 6000/ 10031 20025 10 A.M. Weather: Scattered altocumulus, overcast cirrus fibratus and cirrostratus, few cumulus distant WNW-N, few stratocumulus offshore distant NE-ESE, few lower altocumulus S-SW, breaks in overcast distant NNW-E, sun dimly visible, partial halo Temperature: 32F; Dew Point: 13F; Wind: NW at 7 kts Sea-level pressure: 29.83 ins. Hg, falling slightly Visibility: 75 miles BHO SA 1455 150 SCT E250 OVC 75 103/32/13/3107/983/ FEW CU DSNT WNW-N FEW SC OFFSHR DSNT NE-ESE FEW LWR AC S-SW BINOVC DSNT NNW-E SUN DMLY VSBL PARTIAL HALO WND 38V34/ 8/578 58001 1 P.M. Weather: Scattered altocumulus (2 levels), scattered cirrostratus, thin broken cirrus, few stratocumulus offshore distant ENE-E, few altocumulus lenticularis SE-SW Temperature: 35F; Dew Point: 9F; Wind: NW at 6 kts, Wind: Light and variable Sea-level pressure: 29.82 ins. Hg, falling slightly Visibility: 75 miles 6-hour max. temp: 35F BHO SA 1755 120 SCT 150 SCT 200 SCT 250 –BKN 75 099/35/9/3206/982/ FEW SC OFFSHR DSNT ENE-E FEW ACSL SE-SW WND LGT AND VRB/ 8/538 58004 10035 20027 WEATHER SUMMARY FOR FRIDAY, MARCH 15 TEMPERATURE (DEGREES F) MAX.....39 NORMAL.....44 MIN.....17 NORMAL.....26 MEAN....28 NORMAL.....35 DEPARTURE FROM 30-YEAR NORMAL.......................-7 TOTAL DEPARTURE FOR THE MONTH......................+37 [+2.3 DEGREES/DAY] HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY............37 DEPARTURE............+7 TOTAL HEATING UNITS FOR THE MONTH...........443 DEPARTURE...........-38 TOTAL HEATING UNITS FOR THE SEASON.........4563 DEPARTURE..........-486 TOTAL HEATING UNITS LAST SEASON TO DATE....4029 DIFFERENCE.........+534 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY...............35 NW AT 3:22 A.M. AERO....................37 NW AT 3:21 A.M. ASOS....................37 NW AT 3:23 A.M. DAVIS...................36 NW AT 3:21 A.M. RMY: 34 THE FASTEST MILE FOR YESTERDAY.............29 NW AT 3:22 A.M. MAXIMUM 2-MINUTE ASOS AVERAGE..............25 NW AT 3:23 A.M. MAXIMUM 2-MINUTE DAVIS AVERAGE.............27 NW AT 3:22 A.M. AVERAGE WIND SPEED AND DIRECTION.........14.5 W ASOS..................13.4 DAVIS.................12.7 W [277 deg] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...Trace DEPARTURE...........-0.18 ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........3.96 DEPARTURE...........+1.37 ASOS..............4.20 TOTAL PRECIPITATION FOR THE YEAR..........12.35 DEPARTURE...........+1.34 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.......Trace DEPARTURE............-0.4 TOTAL SNOWFALL FOR THE MONTH..............30.0 DEPARTURE...........+22.7 TOTAL SNOWFALL FOR THE SEASON.............91.2 DEPARTURE...........+36.9 PRELIMINARY CLIMATE SUMMARY FOR MARCH 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 3/1 39/33/36/+5/0.00/0.0/047/07 25 NNW AERO 24 MPH NNW RMY 28 3/2 42/30/36/+5/0.00/0.0/400/59 18 NW AERO 16 MPH NW RMY 21 3/3 42/30/36/+4/0.01/0.2/034/05 17 WNW AERO 15 MPH WNW RMY N/A 3/4 39/26/33/+1/T/T/328/48 32 NW AERO 33 MPH WNW RMY 37 3/5 43/30/37/+5/0/0/123/18 27 WNW AERO 24 MPH WNW RMY N/A 3/6 37/33/35/+3/.../.../000/00 * 47 NE AERO 46 MPH NE RMY 51 3/7 34/29/32/-1/.../.../000/00 * 45 NE AERO 45 MPH NE RMY 47 3/8 37/28/33/0/.../.../000/00 * 41 NNE AERO 39 MPH NNW RMY 45 3/9 40/29/35/+2/0.00/0.0/677/97 29 N AERO 23 MPH N RMY 28 3/10 40/27/34/+1/0.00/0.0/372/53 21 S AERO 17 MPH S RMY N/A 3/11 50/32/41/+7/0.00/0.0/099/14 27 S AERO 25 MPH S RMY N/A 3/12 52/39/46/+12/0.51/0.0/000/00 45 S AERO 46 MPH S RMY 47 3/13 50/33/42/+8/T/0.0/674/95 32 WNW AERO 32 MPH WNW RMY 34 3/14 34/20/27/-8/0.00/0.0/.../.. 37 W AERO 37 MPH NW RMY 38 3/15 39/17/28/-7/0.00/0.0/.../.. 35 NW AERO 37 MPH W RMY 34 3/16 the morning low temp: 25F; the normal low is now 26F * Precipitation and snowfall for calendar days March 6-8 are under review. The records under review are as follows: (inches) March 6 0.19 precip // 0.3 snowfall March 7 1.36 precip // 11.5 snowfall March 8 1.89 precip // 18.0 snowfall DAILY RECORDS FOR MARCH 2013 None so far. Calendar day precipitation and snowfall amounts for 3/6-8 are under review. DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MARCH 16 HIGH 73 IN 1990 LOW 8 IN 1932 PRE 1.95 INS. IN 1900 SNOW 10.0 INS. IN 1896 WIND 79 MPH NE IN 1956 RECORDS FOR MARCH 17 HIGH 69 IN 2003 LOW 6 IN 1885 PRECIP 1.97 INS. IN 1968 SNOWFALL 6.5 INS. IN 1956 PEAK GUST 70 MPH SSW IN 1973 TODAY'S REPORT PREPARED BY: Mike Iacono