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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, MAY 1, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

MAY BEGINS DRY WITH CLOSE TO SEASONABLE TEMPERATURES,
APRIL ENDS WETTER AND COLDER THAN NORMAL...

April's temperatures ran 3.1 degrees below the monthly
normal. April also ended with 1.94 inches more precip 
than the monthly normal.
May started with close to seasonable temperatures. So 
far we reached a max of 60F which is 2 degrees below 
the daily normal of 62F. This morning we measured 0.37 
inches of precipitation from yesterday's rain showers. 
So far today has remained dry. Winds remained light today,
slightly picking up in the afternoon. We had increasing 
visibility from 60 miles at 7:00 A.M. to 80 miles by 
1:00 P.M. today. This was due to decreasing humidity from 
94% at 7:00 A.M. down to 51% at 1:00 P.M. Skies remained 
partly sunny today with a mixture of cumulus and 
cirrus clouds.   

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: 6.49 [+1.94]
Greatest in 24 hrs: N/A

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: Scattered stratocumulus 
Temperature: 45F; Dew Point: 43F; Wind: NW at 6 kts,
Wind: Light  
Sea-level pressure: 30.03 ins. Hg, rising, then more slowly    
Visibility: 60 miles
6-hr Max temp: 45F
6-hr Min temp: 39F
24-hr precip:  0.37 ins. 
24-hr snowfall: 0.0 ins.  
Snow depth: 0 ins.
BHO SA 1155 30 SCT 60 170/45/43/3106/003/ FEW CU DSNT ALNG 
HRZN ALQDS WND LGT/ 8/800 51021 MANUAL 70037 ASOS 70036 10045 

10 A.M.
Weather: Broken cumulus, broken cirrus 
Temperature: 52F; Dew Point: 39F; Wind: NW at 5 kts,
Wind: Light 
Sea-level pressure: 30.03 ins. Hg, rising then falling 
Visibility: 70 miles
3-hr precip: 0.00 ins.  
3-hr snowfall: 0.0 ins. 
BHO SA 1455 E30 BKN 250 BKN 70 170/52/39/3205/003/ 
WND LGT/ 8/101 50000 

1 P.M.
Weather: Scattered stratocumulus, scattered cirrostratus
few cumulus in all directions 
Temperature: 60F; Dew Point: 42F; Wind: WNW at 8 kts
Sea-level pressure: 30.03 ins. Hg, falling unsteadily 
Visibility: 80 miles 
6-hr Max temp: 60F
6-hr Min temp: 45F
6-hr precip:   0.00 ins
6-hr snowfall: 0.0 ins.   
Snow depth: 0 ins.
BHO SA 1755 60 SCT 300 SCT 80 168/60/42/2908/003/ FEW CU ALQDS/ 
8/805 58002 10060 20045
     
SUMMARY FOR MONDAY, APRIL 30, 2018

TEMPERATURE (DEGREES F)
MAX.....46   NORMAL.....61
MIN.....36   NORMAL.....43
MEAN....41   NORMAL.....52

DEPARTURE FROM 30-YEAR NORMAL..........................-11
TOTAL DEPARTURE FOR THE MONTH..........................-87 [-3.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............24   DEPARTURE.........+11
TOTAL HEATING UNITS FOR THE MONTH............635   DEPARTURE.........+84
TOTAL HEATING UNITS FOR THE SEASON..........5693   DEPARTURE........-342
TOTAL HEATING UNITS LAST SEASON TO DATE.....5333   DIFFERENCE.......+360

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................23 WSW AT 12:27 P.M. 
                   AERO........................16 WSW AT 12:27 P.M.* 
                   ASOS........................20 W   AT 12:27 P.M.
                   DAVIS.......................19 M   AT 12:26 A.M.** RMY N/A
FASTEST MILE FOR YESTERDAY.....................13 WSW AT 12:27 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................15 W   AT 10:02 A.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................14 M   AT 12:28 A.M.**
AVERAGE WIND SPEED AND DIRECTION..............5.7 WSW
                   ASOS.......................6.3 
                   DAVIS......................5.3 M**
*  Aerovane reading low
** Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.37  DEPARTURE......+0.22
                         ASOS..............0.36
TOTAL PRECIPITATION FOR THE MONTH..........6.49  DEPARTURE......+1.94
                         ASOS..............6.68  
TOTAL PRECIPITATION FOR THE YEAR..........25.30  DEPARTURE......+6.90
                         ASOS.............26.92

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.........0.0
TOTAL SNOWFALL FOR THE MONTH................2.6  DEPARTURE........-0.4
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/..../0.0/238/31   28 SSE AERO 25 SSE RMY 25
4/04 54/36/45/+3/..../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/..../T/000/00    39 ENE AERO 39 ENE RMY N/A
4/16 55/32/44/-3/..../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/..../0.0/633/78   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

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  Low temp since midnight is 39F; normal low is now 43F

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

RECORDS FOR MAY 1
HIGH 87F IN 1899
LOW 29F IN 1978
PRECIP 2.53 INCHES IN 1921
SNOWFALL TRACE IN 1905,1917,1921,1995,2016
PEAK GUST 57 MPH NW IN 1974

RECORDS FOR MAY 2
HIGH 92F IN 2001
LOW 29F IN 1903
PRECIP 1.36 INCHES IN 2006
SNOWFALL 1.0 INS IN 1888
PEAK GUST 58 MPH S IN 1983

TODAY'S REPORT PREPARED BY: Kaitlin Geagan