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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, APRIL 9, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

A BELOW SEASONABLE DAY WITH SOME HIGH CLOUDS AND 
DRY AIR ON GREAT BLUE HILL....

We observed high clouds that have decreased slightly
since 7 A.M. Humidity has dropped from 55 percent to
25 percent between 7 A.M. and 1 P.M., making for a 
very dry observation day. The low temperature since 
midnight was 24F, 11 degrees below the daily normal
of 35F. The maximum temperature observed at 1 P.M. is 
42F, 11 degrees below the normal maximum of 53. Visibility
has stayed at or above 70 miles most of the day. Winds have
become light and westerly since 2 P.M.                
              
PRELIMINARY STATS FOR MARCH 2018
 
TEMPERATURE, Deg. F
Avg. Max. 41.2 [-3.1]
Avg. Min. 27.9 [+1.3]
Mean      34.6 [-0.9]
24-hour corrected mean: 33.9
Max. for month: 62F on 30th
Min. for month: 10F on 18th
 
HEATING DEGREE DAYS
Total heating units:   941  [+25]
Total for the season: 4063 [-421]
Total for last season: 4902

PRECIPITATION, Inches
Total: 8.68 [+3.10]
Greatest in 24 hrs: 3.47 on the 2nd 

SNOWFALL, Inches
Total: 45.5 [+32.8]
Greatest in 24 hrs: 23.0 in. on 13th
 
WIND, mph
Avg. uncorrected wind speed: 13.9
Avg. corrected wind speed: 14.3
Prevailing wind direction: NW at 14%
Peak gust and direction: 73 NNE on 2nd
 
SUNSHINE:
Campbell-Stokes card minutes: 8742 minutes of possible 21516 or 41%
Astronomical total minutes: 9023 minutes of possible 22243 or 41%

Blue Hill Observatory Greatest March Snowfall Totals, 
Inches (1885-2018)

1) 52.0 in 1956
2) 45.5 in 2018 
3) 42.2 in 1916
4) 41.4 in 2001
5) 41.0 in 1967
6) 37.8 in 2013
7) 35.5 in 1993

BHO Greatest March Monthly Precipitation, 
inches (1885-2018):

1) 18.81 in 2010
2) 13.07 in 2001
3) 10.96 in 1968
4) 10.02 in 1983
5) 9.53 in 1953
6) 9.00 in 1984
7) 8.72 in 1993
8) 8.68 in 2018
9) 8.09 in 1956
10) 7.98 in 1994

Today's Observations:

7 A.M.
Weather: Scattered cirrostratus, few cumulus W-SE, few
cirrus SSE-WNW
Temperature: 29F; Dew Point: 15F; Wind: W at 13G19 kts
Sea-level pressure: 30.09 ins. Hg, rising steadily     
Visibility: 70 miles 
6-hr Max temp: 28F
6-hr Min temp: 24F
24-hr precip:  0.00 ins. 
24-hr snowfall: 0.0 ins. 
Snow depth: 0 ins.
BHO SA 1155 250 SCT 70 193/29/15/2813G20/009/ FEW CU W-SE 
FEW CI SSE-WNW/ 8/108 52023 10028 20024

10 A.M.
Weather: Scattered Cirrostratus, few cirrus overhead
Temperature: 35F; Dew Point: 5F; Wind: NW at 12G19 kts 
Sea-level pressure: 30.13 ins. Hg, rising, then more slowly  
Visibility: 70 miles
3-hr precip: 0.00 ins.  
3-hr snowfall: 0.0 ins. 
BHO SA 1455 250 SCT 70 203/35/5/3212G19/013/ FEW CI OVHD/ 8/005 
51010  

1 P.M.
Weather: Scattered Cirrostratus, few cirrus NE-W
Temperature: 42F; Dew Point: 9F; Wind: WNW at 11G18 kts 
Sea-level pressure: 30.12 ins. Hg, steady then falling
Visibility: 75 miles
6-hr Max temp: 42F
6-hr Min temp: 28F
6-hr precip: 0.00 ins.
6-hr snowfall: 0.0 ins. 
Snow depth: 0 ins.
BHO SA 1755 250 SCT 75 201/42/9/3011G18/012/ FEW CI NE-W/ 8/005 
58002 10042 20028 

SUMMARY FOR SUNDAY, APRIL 8, 2018

TEMPERATURE (DEGREES F)
MAX.....41   NORMAL.....53
MIN.....29   NORMAL.....35
MEAN....35   NORMAL.....44

DEPARTURE FROM 30-YEAR NORMAL...........................-9
TOTAL DEPARTURE FOR THE MONTH..........................-34 [-4.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............30   DEPARTURE..........+9
TOTAL HEATING UNITS FOR THE MONTH............215   DEPARTURE.........+34
TOTAL HEATING UNITS FOR THE SEASON..........5273   DEPARTURE........-392
TOTAL HEATING UNITS LAST SEASON TO DATE.....5089   DIFFERENCE.......+184

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................35 WNW AT 6:37 A.M.*  
                   AERO........................31 WNW AT 6:37 A.M.
                   ASOS........................33 NW  AT 6:37 P.M.
                   DAVIS.......................31 M   AT 5:56 P.M ** RMY 34
FASTEST MILE FOR YESTERDAY.....................24 NW  AT 7:14 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................23 NW  AT 7:14 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE.................22 M   AT 7:14 P.M.**
AVERAGE WIND SPEED AND DIRECTION.............11.1 WNW
                   ASOS......................10.8
                   DAVIS......................9.8 M
*  Estimated
** Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.16
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........1.13  DEPARTURE......-0.22
                         ASOS..............0.82  
TOTAL PRECIPITATION FOR THE YEAR..........19.93  DEPARTURE......+4.76
                         ASOS.............21.06

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE........-0.2
TOTAL SNOWFALL FOR THE MONTH................2.6  DEPARTURE........+1.2
TOTAL SNOWFALL FOR THE SEASON..............92.8  DEPARTURE.......+31.6

PRELIMINARY CLIMATE SUMMARY FOR MARCH 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

3/01 61/37/49/+18/0.00/0.0/378/56    39 ENE AERO 37 ENE RMY N/A 
3/02 40/32/36/+5/3.47/0.7/000/00     73 NNE AERO 70 NNE RMY N/A
3/03 40/32/26/+4/T/T/034/05          52 NNE AERO 50 NNE RMY 49
3/04 39/34/37/+5/T/T/000/00          36 NNE AERO 32 NNE RMY 32 
3/05 40/29/35/+3/0.12/1.2/261/38     40 NE  AERO 39 NE  RMY 40
3/06 34/29/32/0/0.00/0.0/062/09      20 N   AERO 16 N   RMY N/A
3/07 35/31/33/0/1.49/10.0/000/00     52 ENE AERO 53 ENE RMY 50 
3/08 34/28/31/-2/0.67/5.0/000/00     44 NNE AERO 47 NNE RMY N/A
3/09 36/24/30/-3/T/T/265/38          28 W   AERO 26 W   RMY N/A 
3/10 37/28/33/0/0.00/0.0/343/49      38 WNW AERO 38 WNW RMY 41
3/11 42/26/34/0/0.00/0.0/583/83      28 NW  AERO 26 NW  RMY 29
3/12 39/26/33/-1/T/T/155/22          36 ENE AERO 33 ENE RMY N/A
3/13 35/26/31/-3/2.20/23.0/000/00    60 N   AERO 60 N   RMY 64
3/14 36/24/30/-5/0.00/0.0/470/66     38 WSW AERO 38 WSW RMY 41
3/15 40/29/35/0/0.01/0.2/422/59      44 W   AERO 44 W   RMY 44
3/16 35/23/29/-6/0.00/0.0/308/43     41 NW  AERO 41 NW  RMY 45
3/17 40/15/28/-8/0.00/0.0/533/74     46 W   AERO 45 W   RMY 49
3/18 31/10/21/-15/0.00/0.0/694/96    39 NW  AERO 38 NW  RMY 40
3/19 35/13/24/-12/0.00/0.0/704/97    32 WNW AERO 32 WNW RMY 34
3/20 40/18/29/-8/0.00/0.0/372/51     23 NW  AERO 21 NW  RMY N/A
3/21 35/31/33/-4/0.04/0.2/000/00     43 NE  AERO 44 NE  RMY N/A
3/22 39/30/35/-2/0.41/3.4/000/00     28 NNW AERO 26 NNW RMY 30
3/23 44/28/36/-2/0.00/0.0/539/73     21 NNW AERO 18 NNW RMY 21
3/24 45/32/39/+1/T/T/185/25          23 NE  AERO 21 NE  RMY N/A
3/25 36/29/33/-5/0.18/1.8/134/18     35 NNE AERO 30 NNE RMY 33
3/26 38/27/33/-6/0.00/0.0/701/94     33 NE  AERO 26 NE  RMY 30
3/27 44/25/35/-4/0.00/0.0/592/79     24 NE  AERO 17 NE  RMY 20
3/28 55/33/44/+5/0.01/0.0/293/39     21 SSW AERO 14 SSW RMY 18 
3/29 55/39/47/+7/T/0.0/242/32        24 SSE AERO 21 SSE RMY N/A
3/30 62/42/52/+12/0.08/0.0/000/00    32 NW  AERO 30 NW  RMY N/A
3/31 56/35/46/+5/T/0.0/731/96        37 NW  AERO 36 NW  RMY N/A

DAILY RECORDS FOR MARCH 2018

3/02/18: NEW DAILY RECORD MAXIMUM PRECIPITATION OF 3.47 INS.
         PREVIOUS RECORD WAS 2.15 INS. SET IN 1983

3/13/18: NEW DAILY RECORD MAXIMUM SNOWFALL OF 23.0 INS.
         PREVIOUS RECORD WAS 10.0 INS. SET IN 1993

3/13/18: NEW MONTHLY RECORD MAXIMUM DAILY SNOWFALL OF 23.0 INS.
         PREVIOUS RECORD WAS 18.0 INS. SET ON 8 MARCH 2013

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

4/01 58/33/46/+5/..../0.0/.../..   45 SSW AERO 43 SSW RMY N/A  
4/02 38/30/34/-7/..../1.6/.../..   20 SSW AERO 15 SSW RMY 17
4/03 48/30/39/-3/..../0.0/.../..   28 SSE AERO 25 SSE RMY 25
4/04 54/36/45/+3/..../0.0/.../..   56 WNW AERO 56 WNW RMY 54
4/05 40/27/34/-9/0.00/0.0/.../..   53 WNW AERO 53 WNW RMY 52 
4/06 41/25/33/-10/0.25/1.0/.../..  37 S   AERO 36 S   RMY 38
4/07 46/32/35/-4/0.00/0.0/.../..   32 WNW AERO 35 WNW RMY 34
4/08 41/29/35/-9/0.00/0.0/.../..   35 WNW*AERO 31 WNW RMY 34

4/09 Low temp since midnight is 28F; normal low is now 35F

*Estimated

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

RECORDS FOR APRIL 9
HIGH 83 IN 1991
LOW 18 IN 1888
PRECIP 2.38 IN. IN 1935
SNOWFALL 11.0 IN. IN 1917
PEAK GUST 72 MPH WNW IN 1962

RECORDS FOR APRIL 10
HIGH 83 IN 1922
LOW 20 IN 1985
PRECIP 2.40 IN. IN 1935
SNOWFALL 10.1 IN. IN 1996
PEAK GUST 66 MPH WNW IN 1967

TODAY'S REPORT PREPARED BY: Benjamin Turner