BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA DAILY DISCUSSION AND CLIMATE SUMMARY MONDAY, MAY 11, 2020 ALL TIMES ARE IN EASTERN STANDARD TIME SUNNY AND CALM START, TURNED WINDY AND MILD WITH A FEW SHOWERS AROUND... We started the day with plenty of sunshine and light winds. As the morning progressed into the early afternoon clouds rapidly increased along with a stiffening south wind. A few rain showers moved through late this morning into early this afternoon. The showers amounted to 0.01" through the 1pm observation. The wind rather suddenly increased out of the south with gusts around 40 mph at times. The high so far today is 65F, this is normal for the day. The low since midnight is 43F, which is 3 degrees below the daily normal low of 46F. Here are some interesting stats on the cold air mass we just had this past weekend per our Chief Scientist Mike Iacono.. The low temperature of 31F on Sunday was the latest freeze (32F or less) since 32F on May 10, 1977 and the latest 31F or lower since 30F on May 12, 1963.  The latest freeze on record remains 30F on May 16, 1936. Here is the rankings on latest freeze at Blue Hill.. BHO Latest Freezing Temperature, deg F (1885-2020): 1) 30F on 16 May 1936 2) 29F on 12 May 1907    30F on 12 May 1963 4) 28F on 11 May 1900    31F on 11 May 1907    31F on 11 May 1913    30F on 11 May 1923 8) 29F on 10 May 1900    31F on 10 May 1902    31F on 10 May 1947    32F on 10 May 1966    32F on 10 May 1977    31F on 10 May 2020 PRELIMINARY STATS FOR APRIL 2020 TEMPERATURE, Deg. F Avg. Max. 50.6 [-5.1] Avg. Min. 35.8 [-1.9] Mean      43.4 [-3.3] 24-hour corrected mean: 42.9 Max. for month: 63F on the 7th Min. for month: 28F on the 1st HEATING DEGREE DAYS Total heating units:    648 [+97] Total for the season:  5521 [-514] Total for last season: 5900 PRECIPITATION, Inches Total: 7.71 [+3.16] Greatest in 24 hrs: N/A SNOWFALL, Inches Total: 4.3 [+1.3] Greatest in 24 hrs: 4.3 ins. on the 18th WIND, mph Avg. uncorrected wind speed: 13.9 mph Avg. corrected wind speed:   14.3 mph Prevailing wind direction:   W [24%] Peak gust and direction:     79 S on the 13th SUNSHINE: Campbell-Stokes card minutes: 8358 minutes of possible 23250 or 36% Astronomical total minutes: 8676 minutes of possible 24148 or 36% Today's Observations: 7 A.M. Weather: Scattered cirrocumulus Temperature: 50F; Dew Point: 39F; Relative Humidity: 65% Wind: S at 4 kts, wind light   Sea-level pressure: 29.91 ins. Hg: falling, then more slowly Visibility: 40 miles, hazy 6-hr Max temp: 50F 6-hr Min temp: 43F 24-hr Precip:  0.00 ins. 24-hr Snowfall: 0.0 ins. BHO SA 1155 250 SCT 40 129/50/39/1904/991/ WND LGT HAZY/ 8/009 56004 10050 20043 10 A.M. Weather: Scattered altocumulus, broken cirrostratus, thin broken cirrus Temperature: 62F; Dew Point: 34F; Relative Humidity: 34% Wind: S at 14G20 kts. Sea-level pressure: 29.85 ins. Hg: falling, then more rapidly Visibility: 55 miles, hazy 3-hr Precip:  0.00 ins. 3-hr Snowfall: 0.0 ins. BHO SA 1455 130 SCT 180 BKN 250 –BKN 55 110/62/34/1814G20/985/ MDT CU DSNT WSW-WNW HAZY/ 8/272 58019 1 P.M. Weather: Scattered cumulus, broken altocumulus, broken altostratus, overcast cirrostratus, sun dimly visible Temperature: 55F; Dew Point: 44F; Relative Humidity: 66% Wind: S at 15G22 kts, peak wind 28 kts at 12:20 P.M. Sea-level pressure: 29.80 ins. Hg: falling, then more rapidly Visibility: 30 miles, hazy 6-hr Max temp: 65F 6-hr Min temp: 50F 6-hr Precip:  0.01 ins. 6-hr Snowfall: 0.0 ins. BHO SA 1755 45 SCT 90 BKN 140 BKN 180 OVC 30 090/55/44/1715G22/980/ SUN DMLY VSBL HAZY PK WND 1828/20/ RE25/ 8/256 58020 6001 10065 20050 SUMMARY FOR SUNDAY, MAY 10, 2020 TEMPERATURE (DEGREES F) MAX.....59   NORMAL.....65 MIN.....31   NORMAL.....46 MEAN....45   NORMAL.....55 DEPARTURE FROM 30-YEAR NORMAL..................-10 TOTAL DEPARTURE FOR THE MONTH..................-21 [-2.3 DEGREES/DAY] HEATING DEGREE DAYS (SEASON JUL TO JUN) TOTAL HEATING UNITS FOR YESTERDAY...............20  DEPARTURE.......+10 TOTAL HEATING UNITS FOR THE MONTH..............132  DEPARTURE.......+19 TOTAL HEATING UNITS FOR THE SEASON............5653  DEPARTURE......-495 TOTAL HEATING UNITS LAST SEASON TO DATE.......6036  DEPARTURE......-383 COOLING DEGREE DAYS (SEASON JAN TO DEC) TOTAL COOLING UNITS FOR YESTERDAY................0  DEPARTURE........ 0 TOTAL COOLING UNITS FOR THE MONTH................2  DEPARTURE........-1 TOTAL COOLING UNITS FOR THE SEASON...............2  DEPARTURE........-3 TOTAL COOLING UNITS LAST SEASON TO DATE..........0  DEPARTURE........+2 PEAK GUST AND AVERAGE WIND SPEED (MPH) PEAK WIND GUST FOR YESTERDAY....................46 W   AT  4:13 P.M.                      AERO.........................46 W   AT  1:17 P.M.                     ASOS.........................46 W   AT  4:13 P.M.                    DAVIS........................47 WSW AT  1:08 P.M. RMY 49 FASTEST MILE FOR YESTERDAY......................34 W   AT  2:16 P.M. MAXIMUM 2-MINUTE ASOS AVERAGE...................32 W   AT  2:17 P.M. MAXIMUM 2-MINUTE DAVIS AVERAGE..................35 W   AT  2:17 P.M. AVERAGE WIND SPEED AND DIRECTION................16.6 W                                  ASOS.........................15.8                    DAVIS........................16.8 W [261 deg.] PRECIPITATION (INCHES) THROUGH THIS MORNING (EST) TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.12                          ASOS..............0.00 TOTAL PRECIPITATION FOR THE MONTH..........1.39  DEPARTURE......+0.17                          ASOS..............1.39 TOTAL PRECIPITATION FOR THE YEAR..........18.43  DEPARTURE......-1.34                          ASOS.............18.99 SNOWFALL (INCHES) THROUGH THIS MORNING (EST) TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE........0.0 TOTAL SNOWFALL FOR THE MONTH..............Trace  DEPARTURE........0.0 TOTAL SNOWFALL FOR THE SEASON..............31.9  DEPARTURE......-30.8 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  42/28/35/-6/0.00/0.0/008/01         28 NE  AERO 28 NE  RMY 30 04/02  46/35/41/0/0.34/0.0/000/00          39 NW  AER0 40 NW  RMY 41 04/03  42/38/40/-2/2.14/0.0/000/00         48 NE  AERO 53 NE  RMY 49 04/04  46/36/41/-1/0.24/0.0/278/36         38 NE  AERO 38 NE  RMY N/A 04/05  55/36/46/+3/0.00/0.0/039/05         22 S   AERO 21 S   RMY 21 04/06  61/40/51/+8/0.00/0.0/732/94         29 NW  AERO 30 NW  RMY 29 04/07  63/42/53/+10/0.00/0.0/649/83        29 W   AERO 30 W   RMY 28 04/08  50/41/46/+2/0.08/T/047/06           23 S   AERO 22 S   RMY 22 04/09  47/37/42/-2/0.66/T/000/00           58 W   AERO 58 W   RMY 56 04/10  47/35/41/-4/0.02/T/324/41           48 W   AERO 50 W   RMY 53 04/11  51/33/42/-3/0.00/0.0/730/92         38 WNW AERO 39 WNW RMY 40 04/12  60/33/47/+2/0.00/0.0/326/41         38 S   AERO 40 S   RMY N/A 04/13  59/50/55/+9/1.42/0.0/000/00         79 S   AERO 83 S   RMY 78 04/14  57/41/49/+3/0.00/0.0/641/80         41 W   AERO 40 W   RMY N/A 04/15  52/36/44/-3/0.02/0.0/450/56         37 W   AERO 36 W   RMY 37 04/16  47/32/40/-7/T/T/379/47              33 WNW AERO 33 WNW RMY 32 04/17  49/29/39/-8/0.01/0.0/591/73         41 W   AERO 39 W   RMY 41 04/18  37/31/34/-14/0.73/4.3/000/00        29 NE  AERO 25 NE  RMY 25 04/19  60/31/46/-2/0.00/0.0/693/85         40 SSW AERO 40 SSW RMY 41 04/20  49/37/43/-6/0.00/0.0/000/00         25 ENE AERO 22 W   RMY N/A 04/21  53/33/43/-6/0.34/T/271/33         52 S   AERO 52 S   RMY 52 04/22  43/30/37/-12/0.00/0.0/601/73        51 W   AERO 50 W   RMY 50 04/23  55/29/42/-8/0.00/0.0/545/66         31 W   AERO 29 W   RMY N/A 04/24  42/37/40/-10/0.34/0.0/000/00        31 NNE AERO 29 NNE RMY 29 04/25  60/38/49/-1/0.00/0.0/557/67         25 S   AERO 24 S   RMY 24 04/26  51/38/45/-6/0.42/0.0/000/00         51 NE  AERO 50 NE  RMY 50 04/27  39/35/37/-14/0.94/T/000/00          54 NE  AERO 52 NNE RMY 55 04/28  48/35/42/-10/0.00/0.0/159/19        28 N   AERO 27 N   RMY N/A 04/29  55/35/45/-7/0.00/0.0/656/78         24 ENE AERO 23 ENE RMY 22 04/30  52/42/47/-5/0.01/0.0/000/00         36 SE  AERO 32 SE  RMY N/A DAILY RECORDS FOR APRIL 2020 4/13/2020 NEW PEAK GUST OF 79 MPH S, REPLACING THE OLD RECORD OF 59 MPH SSW IN 1995 4/18/2020 NEW RECORD SNOWFALL OF 4.3 INS, REPLACING THE OLD RECORD OF 3.7 INS IN 1965 4/27/2020 NEW RECORD LOW MAX TEMPERATURE OF 39F, REPLACING THE OLD RECORD OF 40F IN 1917 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  64/52/58/+5/..../0.0/.../..         46 SSE  AERO 44 SSE RMY N/A 05/02  70/42/56/+3/..../0.0/.../..         41 NW   AERO 40 NW  RMY N/A 05/03  78/55/67/+14/0.00/0.0/.../..        35 SSW  AERO 35 SSW RMY 36 05/04  72/45/59/+5/T/0.0/.../..            37 NW   AERO 40 WNW RMY 39   05/05  60/40/50/-4/0.00/0.0/.../..         31 NW   AERO 32 NW  RMY N/A 05/06  57/38/48/-6/T/0.0/.../..            24 ESE  AERO 22 ENE RMY 22 05/07  63/37/50/-5/0.00/0.0/.../..         30 WSW  AERO 29 WSW RMY N/A 05/08  57/40/49/-6/..../0.0/.../..         31 W    AERO 32 W   RMY N/A 05/09  44/32/38/-17/..../T/.../..          52 W    AERO 53 W   RMY 54 05/10  59/31/45/-10/0.00/0.0/.../..        46 W    AERO 46 W   RMY 49 05/11 The low since midnight is 43F, the daily normal low is 46F   DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated):   RECORDS FOR MAY 11 HIGH 90F IN 1993 LOW 28F IN 1900 PRE 1.28 INS IN 1957 SNOW 1.0 INS IN 1907 (LATEST MEASURABLE SNOW ON RECORD) PEAK GUST 75e MPH NW IN 1945   RECORDS FOR MAY 12 HIGH 88F IN 2001 LOW 29F IN 1907 PRECIP 1.49 INCHES IN 1968 PEAK GUST 76 MPH S IN 1974 TODAY'S REPORT PREPARED BY: Matt Douglas