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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, APRIL 30, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

A BELOW SEASONABLE DAY WITH LIGHT RAIN SHOWERS, 
DECREASING WINDS, AND OVERCAST SKIES ON GREAT BLUE HILL....

We observed occasional rain showers during the day, 
becoming more frequent after 1:00 P.M. So far, 0.04 
inches of rain have been measured. Winds decreased 
since this morning, becoming light and variable by noontime. 
Temperatures are noticeably below normal, only reaching a 
maximum so far today of 47F. This is 14 degrees below the 
normal daily maximum of 61F. The low since midnight was 36F, 
7 degrees under the normal minimum of 43F.

Today's Observations:

7 A.M.
Weather: Broken stratocumulus and cumulus, broken cirrostratus 
Temperature: 40F; Dew Point: 36F; Wind: NW at 7G11 kts  
Sea-level pressure: 29.91 ins. Hg, rising, then more slowly    
Visibility: 70 miles
6-hr Max temp: 40F
6-hr Min temp: 36F
24-hr precip:  0.04 ins. 
24-hr snowfall: 0.0 ins.  
Snow depth: 0 ins.
BHO SA 1155 E60 BKN 300 BKN 70 129/40/36/2508G14/991/ 8/808 51009 
MANUAL 70004 ASOS 70004 10040 20036  

10 A.M.
Weather: Overcast nimbostratus, light rain
Temperature: 41F; Dew Point: 39F; Wind: W at 9G18 kts 
Sea-level pressure: 29.92 ins. Hg, rising steadily
Visibility: 30 miles, distant fog in all directions
3-hr precip: 0.01 ins.  
3-hr snowfall: 0.0 ins. 
BHO SA 1455 E40 OVC 30R- 132/41/39/2609G18/992/ DSNT FG ALQDS/
8/02/ 53004 MANUAL 60001 ASOS 60001 

1 P.M.
Weather: Broken cumulus and overcast altostratus 
Temperature: 46F; Dew Point: 41F; Wind: WSW at 2 kts,
Wind: Light and variable 
Sea-level pressure: 29.89 ins. Hg, falling, then more slowly  
Visibility: 40 miles 
6-hr Max temp: 47F
6-hr Min temp: 40F
6-hr precip:   0.04 ins
6-hr snowfall: 0.0 ins.   
Snow depth: 0 ins.
BHO SA 1755 E50 BKN 70 OVC 40 125/46/41/2402/989/ BINOVC OVHD WND 
L/V/ 8/22/ 58007 MANUAL 60004 ASOS 60004 10047 20040
     
SUMMARY FOR SUNDAY, APRIL 29, 2018

TEMPERATURE (DEGREES F)
MAX.....59   NORMAL.....61
MIN.....38   NORMAL.....43
MEAN....49   NORMAL.....52

DEPARTURE FROM 30-YEAR NORMAL...........................-3
TOTAL DEPARTURE FOR THE MONTH..........................-76 [-2.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............16   DEPARTURE..........+3
TOTAL HEATING UNITS FOR THE MONTH............611   DEPARTURE.........+73
TOTAL HEATING UNITS FOR THE SEASON..........5669   DEPARTURE........-353
TOTAL HEATING UNITS LAST SEASON TO DATE.....5320   DIFFERENCE.......+344

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................32 SW AT 5:36 P.M. 
                   AERO........................26 SW AT 1:34 P.M. 
                   ASOS........................30 SW AT 1:34 P.M.
                   DAVIS.......................33 M  AT 1:33 P.M.** RMY 31
FASTEST MILE FOR YESTERDAY.....................26 SW AT 5:36 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................23 SW AT 5:36 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................26 M  AT 1:33 P.M.**
AVERAGE WIND SPEED AND DIRECTION..............10.9 W
                   ASOS.......................10.7 WSW
                   DAVIS......................10.2 M **
*  Last of multiple occurrences
** Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.04  DEPARTURE......-0.09
                         ASOS..............0.04
TOTAL PRECIPITATION FOR THE MONTH..........6.13  DEPARTURE......+1.70
                         ASOS..............6.32  
TOTAL PRECIPITATION FOR THE YEAR..........24.93  DEPARTURE......+6.68
                         ASOS.............26.56

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/.../..   39 SSW AERO 38 SSW RMY 41 
4/13 65/47/56/+10/T/0.0/.../..     37 SSW AERO 37 SSW RMY N/A
4/14 51/36/44/-2/0.00/0.0/.../..   33 ENE AERO 31 ENE RMY N/A
4/15 36/30/33/-14/..../T/.../..    39 ENE AERO 39 ENE RMY N/A
4/16 55/32/44/-3/..../.../..       41 ENE AERO 43 ENE RMY 41
4/17 48/36/42/-5/0.00/0.0/.../..   37 W   AERO 33 W   RMY 37
4/18 53/32/43/-5/..../0.0/.../..   35 W   AERO 31 W   RMY 34
4/19 41/34/38/-10/0.22/T/.../..    28 WNW AERO 25 WNW RMY N/A 
4/20 52/31/42/-7/0.00/0.0/.../..   34 NW  AERO 33 NW  RMY 36
4/21 60/33/47/-2/0.00/0.0/.../..   28 NW  AERO 26 NW  RMY 29
4/22 61/36/49/0/0.00/0.0/.../..    25 NW  AERO 24 NW  RMY 26 
4/23 62/40/51/+1/0.00/0.0/.../..   25 S   AERO 25 S   RMY 26
4/24 67/39/53/+3/0.00/0.0/.../..   31 S   AERO 29 S   RMY 32
4/25 57/47/52/+2/..../0.0/.../..   32 SE  AERO 32 SE  RMY 33 
4/26 66/48/57/+6/..../0.0/.../..   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 Low temp since midnight is 36F; normal low is now 43F

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

RECORDS FOR APRIL 30
HIGH 86 IN 1942
LOW 30 IN 1931
PRECIP 1.41 IN 1991
SNOWFALL 0.3 IN. IN 1909
PEAK GUST 64e MPH NW IN 1978

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

TODAY'S REPORT PREPARED BY: Benjamin Turner