BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 4, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

TEMPERATURES BEGIN TO DROP AFTER TWO DAYS OF 
CLOSE TO RECORD BREAKING HIGH TEMPERATURES...

We did break one record yesterday for high minimum
temperature of 67F. The record of 66F was set during 
an early season heatwave back in 2001. Our high max
temperature of 90F was 2 degrees below the record of 
92F also set in 2001. Our daily average yesterday was 
26 degrees above the daily normal. So far today we 
reached a lower but still above seasonable high of 
80F. This is 17 degrees above the daily normal of 63F. 
So far since midnight we have a record breaking high 
minimum temperature of 67F, although this record will 
not stand if temperatures drop below 66F before 
midnight. 
Rain showers began yesterday afternoon at 2:30 P.M.
EST and continued sporadically throughout the day. 
Since yesterday's showers began we have measured 0.18 
ins. of rainfall. 
Skies remained mostly cloudy today with a mixture of 
clouds at each observation. Humidity remained higher
today than yesterday making for very sticky feeling air. 
Wind has remained from the SW/SSW and was light midday
but has begun to pick up this afternoon. Visibility 
was limited due to a distant fog today but improved 
from 20 miles in the morning to 40 miles at 1:00 P.M.

PRELIMINARY STATS FOR APRIL 2018
 
TEMPERATURE, Deg. F
Avg. Max. 52.4 [-3.3]
Avg. Min. 34.9 [-2.8]
Mean      43.7 [-3.0]
24-hour corrected mean: 43.1
Max. for month:  73F on 28th
Min. for month:  24F on  9th
 
HEATING DEGREE DAYS
Total heating units:    635  [+84]
Total for the season:  5693 [-342]
Total for last season: 5333

PRECIPITATION, Inches
Total: 6.51 [+1.93]
Greatest in 24 hrs: 2.85 on the 15-16th 

SNOWFALL, Inches
Total: 2.6 [-0.4]
Greatest in 24 hrs: 1.6 in. on 2nd
 
WIND, mph
Avg. uncorrected wind speed: 12.2
Avg. corrected wind speed: 12.6
Prevailing wind direction: WNW at 16%
Peak gust and direction: 56 NW on the 2nd 
 
SUNSHINE:
Campbell-Stokes card minutes:N/A
Astronomical total minutes: N/A

Today's Observations:

7 A.M.
Weather: Light rain, scattered nimbostratus, broken 
altocumulus, and overcast altostratus   
Temperature: 67F; Dew Point: 64F; Wind: SW at 4 kts,
Wind: Light 
Sea-level pressure: 29.94 ins. Hg, rising, then more slowly    
Visibility: 20 miles, distant fog in all directions
6-hr Max temp: 69F
6-hr Min temp: 67F
24-hr precip:  0.16 ins. 
24-hr snowfall: 0.0 ins.  
Snow depth: 0 ins.
BHO SA 1155 65 SCT E100 BKN E200 OVC 20R- 139/67/64/2304/994/ 
DSNT FG ALQDS WND LGT/ 8/72/ 53008 MANUAL 70016 ASOS 70015 
10069 20067 

10 A.M.
Weather: Scattered altocumulus, overcast altostratus, and
few cumulus SSW-NNW
Temperature: 86F; Dew Point: 53F; Wind: SW at 9G16 kts
Sea-level pressure: 29.95 ins. Hg, falling, then more rapidly  
Visibility: 20 miles, distant fog in all directions 
3-hr precip: 0.02 ins.  
3-hr snowfall: 0.0 ins. 
BHO SA 1455 70 SCT E140 OVC 20 136/73/65/2103/993/ 
FEW CU SSW-NNW DSNT FG ALQDS WND LGT/ 8/21/ 58003 
MANUAL 6002/ ASOS 60002 

1 P.M.
Weather: Scattered altocumulus, broken cirrostratus, and
a few cumulus SSW-NNW  
Temperature: 80F; Dew Point: 54F; Wind: SSW at 10G17 kts
Sea-level pressure: 29.87 ins. Hg, falling, then more rapidly 
Visibility: 40 miles, distant fog in all directions 
6-hr Max temp: 80F
6-hr Min temp: 67F
6-hr precip:   0.02 ins
6-hr snowfall: 0.0 ins.   
Snow depth: 0 ins.
BHO SA 1755 100 SCT E230 BKN 40 114/80/54/2010G17/987/ FEW CU 
SSW-NNW DSNT FG ALQDS/ 8/292 58022 MANUAL 6002/ ASOS 60002 
10080 20067
     
SUMMARY FOR THURSDAY, MAY 3, 2018

TEMPERATURE (DEGREES F)
MAX.....90   NORMAL.....63
MIN.....67   NORMAL.....44
MEAN....79   NORMAL.....53

DEPARTURE FROM 30-YEAR NORMAL.........................+26 
TOTAL DEPARTURE FOR THE MONTH.........................+46 [+15.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............0   DEPARTURE.........-13
TOTAL HEATING UNITS FOR THE MONTH.............13   DEPARTURE.........-24
TOTAL HEATING UNITS FOR THE SEASON..........5706   DEPARTURE........-366
TOTAL HEATING UNITS LAST SEASON TO DATE.....5374   DIFFERENCE.......+332

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY..............14   DEPARTURE..........14
TOTAL COOLING UNITS FOR THE MONTH..............23   DEPARTURE.........+22
TOTAL COOLING UNITS FOR THE SEASON.............23   DEPARTURE.........+20
TOTAL COOLING UNITS LAST SEASON TO DATE........20   DEPARTURE..........+3

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................36 SW AT  1:17 P.M. 
                   AERO........................32 SW AT  1:17 P.M.* 
                   ASOS........................36 SW AT  1:17 P.M.
                   DAVIS.......................37 M  AT  1:17 P.M.** RMY 35
FASTEST MILE FOR YESTERDAY.....................26 SW AT 12:55 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................25 SW AT  1:17 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................28 M  AT  1:18 P.M.**
AVERAGE WIND SPEED AND DIRECTION.............11.6 SW
                   ASOS......................12.3 
                   DAVIS.....................11.3 M**
*  Last of multiple occurrences
** Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.16  DEPARTURE......+0.03
                         ASOS..............0.15
TOTAL PRECIPITATION FOR THE MONTH..........0.16  DEPARTURE......-0.21
                         ASOS..............0.15  
TOTAL PRECIPITATION FOR THE YEAR..........25.47  DEPARTURE......+6.67
                         ASOS.............27.07

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.........0.0
TOTAL SNOWFALL FOR THE SEASON..............92.8  DEPARTURE.......+30.0

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
*   : Estimated data 

4/01 58/33/46/+5/0.00/0.0/336/44   45 SSW AERO 43 SSW RMY N/A  
4/02 38/30/34/-7/0.13/1.6/077/10   20 SSW AERO 15 SSW RMY 17
4/03 48/30/39/-3/0.54/0.0/238/31   28 SSE AERO 25 SSE RMY 25
4/04 54/36/45/+3/0.21/0.0/000/00   56 WNW AERO 56 WNW RMY 54
4/05 40/27/34/-9/0.00/0.0/760/98   53 WNW AERO 53 WNW RMY 52 
4/06 41/25/33/-10/0.25/1.0/156/20  37 S   AERO 36 S   RMY 38
4/07 46/32/35/-4/0.00/0.0/312/40   32 WNW*AERO 35 WNW RMY 34
4/08 41/29/35/-9/0.00/0.0/290/37   35 WNW*AERO 31 WNW RMY 34
4/09 45/24/35/-9/0.00/0.0/715/01   28 WNW AERO 25 WNW RMY 29
4/10 39/31/35/-10/T/T/000/00       14 SSW AERO 13 SSW RMY N/A
4/11 48/29/39/-6/T/0.0/364/46      24 SSE AERO 23 SSE RMY 25 
4/12 61/33/47/+2/0.03/0.0/500/63   39 SSW AERO 38 SSW RMY 41 
4/13 65/47/56/+10/T/0.0/096/12     37 SSW AERO 37 SSW RMY N/A
4/14 51/36/44/-2/0.00/0.0/328/41   33 ENE AERO 31 ENE RMY N/A
4/15 36/30/33/-14/0.32/T/000/00    39 ENE AERO 39 ENE RMY N/A
4/16 55/32/44/-3/2.63/000/00       41 ENE AERO 43 ENE RMY 41
4/17 48/36/42/-5/0.00/0.0/210/26   37 W   AERO 33 W   RMY 37
4/18 53/32/43/-5/0.00/0.0/633/78   35 W   AERO 31 W   RMY 34
4/19 41/34/38/-10/0.22/T/000/00    28 WNW AERO 25 WNW RMY N/A 
4/20 52/31/42/-7/0.00/0.0/522/64   34 NW  AERO 33 NW  RMY 36
4/21 60/33/47/-2/0.00/0.0/811/99   28 NW  AERO 26 NW  RMY 29
4/22 61/36/49/0/0.00/0.0/821/100   25 NW  AERO 24 NW  RMY 26 
4/23 62/40/51/+1/0.00/0.0/816/99   25 S   AERO 25 S   RMY 26
4/24 67/39/53/+3/0.00/0.0/645/78   31 S   AERO 29 S   RMY 32
4/25 57/47/52/+2/..../0.0/000/00   32 SE  AERO 32 SE  RMY 33 
4/26 66/48/57/+6/..../0.0/308/37   36 WNW AERO 35 WNW RMY 37 
4/27 60/45/53/+2/..../0.0/.../..   18 W   AERO 15 W   RMY N/A
4/28 73/47/60/+8/0.00/0.0/.../..   25 S   AERO 21 S   RMY 25
4/29 59/38/49/-3/0.04/0.0/.../..   32 SW  AERO 26 SW  RMY 31
4/30 46/36/41/-11/0.37/0.0/.../..  23 WSW AERO 16 WSW RMY N/A

DAILY RECORDS FOR APRIL 2018

4/16/18: NEW DAILY RECORD MAXIMUM PRECIPITATION OF 2.63 INS.
         PREVIOUS RECORD WAS 2.45 INS. SET IN 1929

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

5/1 65/39/52/-1/0.00/0.0/.../..    25 WNW AERO 21 WNW RMY 25
5/2 88/59/74/+21/0.00/0.0/.../..   37 WSW AERO 29 WSW RMY 35 
5/3 90/67/70/+26/..../0.0/.../..   36 SW  AERO 32 WSW RMY 36  

5/4  Low temp since midnight is 67F; normal low is now 44F

DAILY RECORDS FOR MAY 2018

5/03/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 67F,
         BREAKS PREVIOUS RECORD OF 66F SET IN 2001

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):    

RECORDS FOR MAY 4
HIGH 90F IN 2001
LOW 27F IN 1911 (RECORD FOR MAY)
PRECIP 1.92 INCHES IN 1893
SNOWFALL 0.1 INCHES IN 1920
PEAK GUST 60 MPH NW IN 1966

RECORDS FOR MAY 5
HIGH 92F IN 1949
LOW 30F IN 1891
PRECIP 2.74 INCHES IN 1922
SNOWFALL 3.0 INCHES IN 1917
PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976

TODAY'S REPORT PREPARED BY: Kaitlin Geagan