BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY TUESDAY, MAY 21, 2019 ALL TIMES ARE IN EASTERN STANDARD TIME GUSTY WINDS AND SEASONABLE CONDITIONS ON TOP OF THE GREAT BLUE HILL At the 7 A.M. observation, 0.35 inches was observed in the rain gauge from passing thunderstorms on the afternoon of the 20th. Winds have been gusty throughout the day with a peak gust of 38 miles per hour reported by the 420c. Skis remained partly cloudy and visibility 75 miles through the 1 P.M. observation. The high so far today is 67F, 1 degrees below the normal maximum of 68F. The low since midnight is 51 F, 3 degree above the normal daily minimum of 48F. PRELIMINARY STATS FOR APRIL 2019 TEMPERATURE, Deg. F Avg. Max. 57.2 [+1.5] Avg. Min. 39.3 [+1.6] Mean 48.3 [+1.6] 24-hour corrected mean: 47.3 Max. for month: 71F on the 13th, 14th, and 19th Min. for month: 27F on the 2nd and 5th HEATING DEGREE DAYS Total heating units: 496 [-55] Total for the season: 5901 [-134] Total for last season: 5693 PRECIPITATION, Inches Total: 8.14 [+3.59] Greatest in 24 hrs: 3.00 ins. on the 22nd-23rd SNOWFALL, Inches Total: Trace [-3.0] Greatest in 24 hrs: Trace on the 10th WIND, mph Avg. uncorrected wind speed: 13.2 Avg. corrected wind speed: 13.6 Prevailing wind direction: S at 15% Peak gust and direction: 54 W on 3rd SUNSHINE: Campbell-Stokes card minutes: 8238 minutes of possible 23250 or 35% Astronomical total minutes: 8543 minutes of possible 24086 or 35% BHO Greatest April Precipitation, inches (1886-2019): 1) 10.37 in 1987 2) 9.38 in 2004 3) 8.71 in 1929 4) 8.68 in 2007 5) 8.53 in 1904 6) 8.14 in 2019 7) 7.57 in 1935 7.57 in 1983 9) 7.31 in 1901 The calendar day rainfall on Monday, 4/22, was more than two and a half inches, which made it one of the wettest calendar days ever observed in April. The finalized amount for the day is now available. BHO Greatest April Calendar Day Precipitation, inches (1886-2019): 1) 3.47 on April 1, 2004 2) 3.18 on April 21, 1991 3) 2.63 on April 16, 2018 4) 2.60 on April 22, 2019 5) 2.51 on April 24, 1898 2.51 on April 13, 2004 6) 2.45 on April 16, 1929 7) 2.41 on April 28, 1904 8) 2.40 on April 10, 1935 BHO Lowest April Sunshine, hours (1886-2019): 1) 82.6 in 1901 [21%] 2) 121.1 in 1987 [31%] 3) 121.7 in 1988 [31%] 4) 131.6 in 1983 [34%] 5) 132.2 in 1921 [34%] 6) 137.3 in 2019 [35%] 7) 138.1 in 1939 [36%] 8) 140.7 in 1955 [36%] 9) 141.1 in 2000 [36%] Today's Observations: 7 A.M. Weather: Scattered cumulus, few altocumulus Temperature: 53F; Dew Point: 43F; Wind: WNW at 21G29 kts, Sea-level pressure: 29.76 ins. Hg, falling then rising Visibility: 75 miles 6-hr Max temp: 85F 6-hr Min temp: 52F 24-hr Precip: 0.35 ins. 24-hr snowfall: 0.0 ins. Snow depth: 0 ins. BHO SA 1155 05 SCT 75 080/53/43/2921G29/976/ FEW AC NE-E PK WND 2930/55 8/100 53014 70035 10085 20052 10 A.M. Weather: Scattered cumulus, few altocumulus Temperature: 62F; Dew Point: 50F; Wind: WSW at 19G28 kts, Sea-level pressure: 29.75 ins. Hg, rising then falling Visibility: 75 miles 3-hr Precip: 0.00 ins. BHO SA 1455 52 SCT 75 077/62/50/2919G28/975/ FEW AC ALQDS PK WND 2928/20 8/100 58003 1 P.M. Weather: Scattered cirrostratus, few cumulus Temperature: 66F; Dew Point: 36F; Wind: WNW at 15G28 kts Sea-level pressure: 29.75 ins. Hg, rising then falling Visibility: 75 miles, 6-hr Max temp: 67F 6-hr Min temp: 60F 6-hr Precip: 0.00 ins. BHO SA 1755 250 SCT 75 077/66/36/3015G28/975/ FEW CU ALQDS PK WND 3034/44 8/008 50004 10067 20060 SUMMARY FOR MONDAY, MAY 20, 2019 TEMPERATURE (DEGREES F) MAX.....69 NORMAL.....68 MIN.....50 NORMAL.....49 MEAN....60 NORMAL.....58 DEPARTURE FROM 30-YEAR NORMAL........................-8 TOTAL DEPARTURE FOR THE MONTH.......................-75 [-3.75 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY...............0 DEPARTURE..........0 TOTAL HEATING UNITS FOR THE MONTH.............249 DEPARTURE........+49 TOTAL HEATING UNITS FOR THE SEASON...........6150 DEPARTURE........-85 TOTAL HEATING UNITS LAST SEASON TO DATE......5817 DIFFERENCE......+333 COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY...............4 DEPARTURE..........0 TOTAL COOLING UNITS FOR THE MONTH...............4 DEPARTURE.........-5 TOTAL COOLING UNITS FOR THE SEASON.............-7 DEPARTURE.........11 TOTAL COOLING UNITS LAST SEASON TO DATE........37 DEPARTURE........-33 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY....................35 SW AT 3:03 P.M. AERO.........................40 SW AT 3:00 P.M. ASOS.........................35 W AT 3:03 P.M. DAVIS........................38 S AT 3:14 P.M. RMY 39 FASTEST MILE FOR YESTERDAY......................26 SW AT 3:01 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...................25 W AT 3:03 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..................26 WSW AT 3:04 P.M. AVERAGE WIND SPEED AND DIRECTION...............14.8 SSW ASOS........................13.7 DAVIS.......................14.5 WSW [204 deg.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.35 DEPARTURE.......0.01 ASOS..............0.37 TOTAL PRECIPITATION FOR THE MONTH..........3.00 DEPARTURE.......+0.17 ASOS..............2.82 TOTAL PRECIPITATION FOR THE YEAR..........24.18 DEPARTURE.......+3.15 ASOS.............24.03 PRELIMINARY CLIMATE SUMMARY FOR APRIL CALENDAR DAY DATA DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST AERO: Aerovane wind recording system gust RMY: R.M. Young wind gust recording system TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized M: Missing data 04/01 45/29/37/-4/0.00/0.0/748/98 40 WNW AERO 37 W RMY 42 04/02 50/27/39/-2/0.08/0.0/605/79 29 S AERO 25 S RMY 31 04/03 62/35/49/+7/0.36/0.0/484/63 54 W AERO 58 W RMY 56 04/04 50/34/42/0/0.00/0.0/717/93 46 W AERO 41 W RMY N/A 04/05 47/27/37/-6/0.10/0.0/341/44 23 SSW AERO 17 SSW RMY 23 04/06 64/32/48/+5/0.12/0.0/536/69 24 NW AERO 18 W RMY 26 04/07 66/41/54/+11/0.00/0.0/320/41 24 S AERO 18 S RMY 25 04/08 48/34/41/-3/0.49/0.0/000/00 25 NE AERO 20 NE RMY 26 04/09 40/32/36/-8/0.08/0.0/000/00 23 NE AERO 16 N RMY 25 04/10 43/30/37/-8/T/T/000/00 32 NW AERO 26 NW RMY 36 04/11 51/29/40/-5/0.00/0.0/403/51 23 NW AERO 18 NW RMY N/A 04/12 53/38/46/+1/0.15/0.0/000/00 35 SSW AERO 29 SSW RMY 39 04/13 71/54/63/+17/0.38/0.0/167/21 38 SSW AERO 32 SSW RMY N/A 04/14 71/51/61/+15/0.15/0.0/224/28 25 S AERO 18 S RMY N/A 04/15 67/40/54/+7/0.93/0.0/168/21 46 W AERO 52 W RMY 50 04/16 58/37/48/+1/0.00/0.0/805/100 46 W AERO 44 W RMY 44 04/17 62/36/49/+2/0.00/0.0/807/100 26 ESE AERO 25 S RMY 28 04/18 63/39/51/+3/T/0.0/000/00 44 S AERO 44 S RMY 50 04/19 71/58/65/+17/0.03/0.0/049/06 47 SSW AERO 51 SSW RMY 52 04/20 68/60/64/+15/0.46/0.0/000/00 50 SSW AERO 54 SSW RMY 52 04/21 68/51/60/+11/0.06/0.0/123/15 35 S AERO 35 S RMY N/A 04/22 53/45/49/0/2.60/0.0/000/00 35 NNE AERO 32 NNE RMY 35 04/23 52/44/48/-2/0.42/0.0/041/05 30 NNE AERO 26 NNE RMY N/A 04/24 65/44/55/+5/0.02/0.0/438/53 29 WNW AERO 29 WNW RMY 30 04/25 61/39/50/0/0.00/0.0/696/84 22 S AERO 22 S RMY 21 04/26 53/42/48/-3/0.84/0.0/000/00 35 ESE AERO 30 W RMY 33 04/27 54/39/47/-4/0.62/0.0/100/12 41 W AERO 44 W RMY 47 04/28 51/38/45/-7/0.08/0.0/159/19 28 W AERO 28 W RMY N/A 04/29 60/34/47/-5/0.00/0.0/612/73 23 NW AERO 24 WNW RMY 24 04/30 48/40/44/-8/0.17/0.0/000/00 26 NW AERO 23 NW RMY 25 PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST AERO: Aerovane wind recording system gust RMY: R.M. Young wind gust recording system TSTM: Thunderstorm day (thunder heard some time during day) ....: Data not yet available, records not finalized M: Missing data 05/01 57/40/49/-4/0.00/0.0/.../.. 21 S AERO 21 SSE RMY 21 05/02 45/41/43/-10/0.02/0.0/.../.. 21 NE AERO 21 SSW RMY 20 05/03 60/43/52/-1/..../.../.../.. 23 S AERO 23 S RMY 22 05/04 54/46/50/-4/..../.../.../.. 14 ENE AERO 14 ENE RMY 17 05/05 52/44/48/-6/0.00/0.0/.../.. 18 NE AERO 20 NE RMY N/A 05/06 58/44/51/-3/..../0.0/.../.. 25 NE AERO 26 ENE RMY 24 05/07 72/41/57/+2/0.12/0.0/.../.. 30 S AERO 29 S RMY 30 05/08 67/48/58/+3/0.00/0.0/.../.. 20 NE AERO 20 NE RMY 19 05/09 60/43/52/-3/0.00/0.0/.../.. 21 SE AERO 21 E RMY 22 05/10 61/46/54/-1/0.16/0.0/.../.. 35 S AERO 37 S RMY 37 05/11 68/50/59/+3/..../.../.../.. 26 NW AERO M M RMY N/A 05/12 50/36/43/-13/0.68/.../.../.. 30 ENE AERO M M RMY N/A 05/13 52/38/45/-11/..../.../.../.. 35 E AERO M M RMY 34 05/14 44/38/41/-16/..../.../.../.. 26 NNE AERO M M RMY 25 05/15 58/40/49/-8/..../.../.../.. 28 NW AERO M M RMY 28 05/16 68/46/57/0/..../.../.../.. 17 NW AERO M M RMY 19 05/17 64/49/57/0/..../.../.../.. 22 WNW AERO 21 WNW RMY 25 05/18 72/49/61/+3/..../.../.../.. 26 SSE AERO 25 SSE RMY 29 05/19 69/50/60/+2/..../.../.../.. 39 S AERO 43 SSE RMY 42 05/20 85/52/69/11/..../.../.../.. 35 SW AERO 40 SW RMY 39 5/21 Low temp since midnight is 50F; normal low is 49F DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated): RECORDS FOR MAY 20 HIGH 91F IN 1975,1996 LOW 37F IN 1948, 2002 PRECIP 1.65 INCHES IN 1969 PEAK GUST 57 MPH S IN 1963, WNW IN 1982 RECORDS FOR MAY 21 HIGH 92F IN 1921 LOW 35F IN 1907 PRECIP 1.61 INS IN 1954 PEAK GUST 74 MPH WSW IN 2006 TODAY'S REPORT PREPARED BY: Nicholas Rousseau