BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS 02186 ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY FRIDAY, MAY 18, 2007 ALL TIMES ARE IN EASTERN STANDARD TIME LIKELY TO SET NEW RECORD LOW MAXIMUM TEMPERATURE TODAY ALMOST ONE INCH OF RAIN THROUGH EARLY THIS AFTERNOON Temperatures stuck in the very chilly lower 40's today will likely set a new record low maximum temperature for this date. The high reading has been only 42 degrees occurring very early this morning and the record low maximum for this date is 48 degrees in 1895 and 1956. Light to moderate rainfall since around 1 a.m. EDT this morning has totaled almost an inch by early this afternoon. Today's observations: 7 A.M. Weather: Low overcast, modt. rain and fog Temperature: 40F, Dew point: 40F, Wind: NNE at 15G29 kts Wind: Peak gust 29 kts NNE @ 51 past the hour, direction variable from NNW to NE Sea-level pressure: 30.25 inches Hg, steady Visibility: 2 miles, 1/2-1 N-NE 24-hourly precip: 0.60 inch 6- hourly min temp. 40 deg. BHO SA 1155 E3 OVC 2RF 244/40/40/0215G29/025/ CIG RGD STRA DRFTG OVR SMT VSBY N-NE 1/2V1 PK WND 0229/51/ WND 34V05 R OCNL R-/ 8/7// 51003 MANUAL 6059/ ASOS 60058 MANUAL 70060 ASOS 70059 10041 20040 10 A.M. Weather: Low overcast stratus fractus, light rain & fog Temperature: 41F, Dew point: 40F, Wind: NNE at 15G27 kts Wind: Peak gust 32 kts NNE @ 36 past the hour, direction variability NNW-NE Sea-level pressure: 30.21 inches Hg, rising Visibility: 6 miles 3-hourly rainfall: 0.16 in. BHO SA 1455 E5 OVC 6R-F 230/41/40/0215G27/021/ CIG RGD STFRA DRFTG BLO OCNL OVR SMT PK WND 0232/36/ WND 33V05/ 8/7// 55014 ASOS 60016 MANUAL 6017/ 1 P.M. Weather: Low overcast, moderate rain and fog Temperature: 40F, Dew point: 40F, Wind: N at 11G25 kts Wind: direction variability NNW-NNE Sea-level pressure: 30.17 inches Hg, falling Visibility: 21/2 miles variable 2-3 miles Six hourly max. temp: 41 deg. BHO SA 1755 E4 OVC 21/2RF 217/40/40/3611G25/017/ CIG RGD STFRA DRFTG OVR AND BLO SMT VSBY 2V3 WND 33V03/ 8/7// 58013 ASOS 60036 MANUAL 6037/ 10041 20040 WEATHER SUMMARY FOR THURSDAY, MAY 17 TEMPERATURE (DEGREES F) MAX.....50 NORMAL.....68 MIN.....42 NORMAL.....47 MEAN....46 NORMAL.....57 DEPARTURE FROM 30-YEAR NORMAL..........-11 TOTAL DEPARTURE FOR THE MONTH..........+52 (+2.9 DEGREES/DAY) HEATING DEGREE DAYS TOTAL HEATING UNITS FOR YESTERDAY...........19 DEPARTURE........+11 TOTAL HEATING UNITS FOR THE MONTH..........136 DEPARTURE........-44 TOTAL HEATING UNITS FOR THE SEASON........5752 DEPARTURE.......-456 TOTAL HEATING UNITS LAST SEASON TO DATE...5643 DIFFERENCE......+109 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY............28 NE AT 9:44 P.M. * AEROVANE.............24 NE AT 9:44 P.M. * ASOS.................29 NE AT 9:44 P.M. DAVIS................26 ENE AT 8:49 P.M. FASTEST MILE FOR YESTERDAY..............19 NE AT 8:50 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...........20 NE AT 11:13 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..........20 ENE AT 8:50 P.M. AVERAGE WIND SPEED AND DIRECTION....... 9.2 NE ASOS FOR THE DAY........................9.9 DAVIS FOR THE DAY ......................8.7 NE [050 deg] * last of several occurrences... PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.60 DEPARTURE.....+0.48 ASOS..............0.59 TOTAL PRECIPITATION FOR THE MONTH..........1.26 DEPARTURE.....-0.83 ASOS..............1.19 TOTAL PRECIPITATION FOR THE YEAR..........21.68 DEPARTURE....+1.64 ASOS.............21.16 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0 DEPARTURE.......0.0 TOTAL SNOWFALL FOR THE MONTH................0.0 DEPARTURE......-0.1 TOTAL SNOWFALL FOR THE SEASON..............27.6 DEPARTURE.....-32.5 PRELIMINARY CLIMATE SUMMARY FOR MAY 2007......CALENDAR DAY DATA DATA REPORTED: DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOWFALL/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST AERO: Aerovane recording wind system when significant TSTM: Thunderstorm day ....: Data not yet available 5/1 67/44/56/+4/0/0/624/74 33 NW 5/2 64/45/55/+3/0.06/0/381/45 36 NW Aero 33 MPH WNW 5/3 67/42/55/+2/0/0/849/100 38 W Aero 37 MPH W 5/4 66/44/55/+2/0/0/842/99 39 WNW Aero 40 MPH WNW 5/5 65/45/55/+2/0/0/384/45 33 N 5/6 51/42/47/-7/T/0/514/60 36 N Aero 33 MPH N 5/7 68/39/54/0/0/0/798/93 25 S 5/8 77/43/60/+6/0/0/851/99 33 S Aero 31 MPH S 5/9 85/54/70/+15/0/0/707/92 30 S 5/10 85/60/73/+18/0/0/692/80 29 S Aero 27 MPH S 5/11 74/60/67/+12/0.02/0/355/41 23 S 5/12 63/47/55/-1/0.02/0/469/54 32 NE 5/13 65/46/56/0/T/0/775/89 33 WNW Aero 33 MPH WNW 5/14 73/43/58/+1/0/0/822/94 30 SSW 5/15 80/50/65/+8/0.01/0/210/24 30 S TSTM evening 5/16 66/44/55/-2/0.54/0/527/60 40 NW TSTM P.M. 5/17 50/42/46/-11/0.01/0/.../.. 28 NE 5/18 morning low temp. 40 deg; normal now 48 deg. rainfall midnight to 7 a.m. 0.60 inch DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 18 HIGH 88F IN 1906, 1936, 1986 LOW 35F IN 2002 PRE 1.58 INS IN 2002 SNOW TRACE IN 2002 (Ice pellets) PEAK GUST 64 MPH SSW IN 2000 RECORDS FOR MAY 19 HIGH 91F IN 1962 LOW 34F IN 2002 PRECIP 1.54 INCHES IN 1900 PEAK GUST 58 MPH NW IN 1964 TODAY'S REPORT PREPARED By: Robert Skilling