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

SUNDAY, APRIL 18, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0459E
SUNSET:  1829E

INCREASINGLY CLOUDY WITH THE WIND PICKING UP
IN THE AFTERNOON HOURS....

We observed 55 miles of visibility on average today,
as the sky became covered by more and more clouds.
Wind is westerly with an average speed of 10 mph and
a max gust of 20 so far today.

The rainfall and snowfall we received over the last few
days has helped a little in the precipitation department.
The departure for rainfall on the month is +0.73 inches,
with an annual deficit of 3.09 inches. Snowfall departure
is +1.2 on the month with an annual surplus of +14.6
inches.  

The high so far today is 56F, this is a degree below the
normal high of 57F. The low since midnight is 38F, which is
a degree below the daily normal low of 39F.


Today's Observations:

7 A.M.
Weather: Broken stratocumulus and cirrostratus
Temperature: 43F; Dew Point: 36F; Relative Humidity: 76%
Wind: WNW at 5 kts, wind light
Sea-level pressure: 29.80 in Hg, rising steadily  
Visibility: 40 miles
6-hr Max temp: 43F
6-hr Min temp: 38F
24-hr Precip: 0.02 ins.
24-hr Snow: Trace
Snow Depth: 0.0 ins.
BHO SA 1155 50 BKN 250 BKN 40 092/43/36/3005/980/ WND LGT
NEW SNW PST 24 HRS TRACE/ 8/806 70002 53008 10043 20038

10 A.M.
Weather: Scattered cumulus, broken altocumulus and
cirrostratus
Temperature: 49F; Dew Point: 34F; Relative Humidity: 54%
Wind: NW @ 7 kts
Sea-level pressure: 29.79 in Hg; falling steadily
Visibility: 55 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 40 SCT 140 BKN 250 BKN 55 088/49/34/3107/979/
8/156 58004

1 P.M.
Weather: Broken stratocumulus, altocumulus, and
cirrostratus
Temperature: 54F, Dew point: 34F; Relative Humidity: 46%
Wind: NW @ 13G21 kts
Sea-level pressure: 29.76 in Hg; falling steadily
Visibility: 65 miles
6-hr Max temp: 56F
6-hr Min temp: 43F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 50 BKN 140 BKN 250 OVC 65 077/54/34/3113G21/976/
8/856 58011 10056 20043


SUMMARY FOR SATURDAY, APRIL 17, 2021

TEMPERATURE (DEGREES F)
MAX.......45     NORMAL.....56
MIN.......34     NORMAL.....38
MEAN......40     NORMAL.....47

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL.......-7
TOTAL DEPARTURE FOR THE MONTH...................+24 [+1.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............25  DEPARTURE.......+7
TOTAL HEATING UNITS FOR THE MONTH..............330  DEPARTURE......-24
TOTAL HEATING UNITS FOR THE SEASON............5152  DEPARTURE.....-686
TOTAL HEATING UNITS LAST SEASON TO DATE.......5226  DEPARTURE......-74

PEAK WIND GUST (MPH):
                     420C/Official..............27 NNW @ 12:05 A.M.
                     AEROVANE (south tower).....30 NNW @ 12:02 A.M.
                     ASOS.......................28 NW  @ 12:04 A.M.
                     DAVIS #1...................28 NNW @ 12:05 A.M.
                     DAVIS #2 (south tower).....27 NNW @ 12:04 A.M.
                     RMY........................29     @ 12:04 A.M.
                     VECTOR.....................32     @ 12:05 A.M.
                     MERLIN.....................M

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL..................21 NNW @ 12:08 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE...................18 NNW @ 12:09 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE...............20 NNW @ 12:10 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE...............20 N   @ 12:07 A.M.
MAXIMUM 2-MINUTE RMY AVERAGE....................19 NNW @ 12:06 A.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE.................19     @ 12:06 A.M.

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL......10.2 NNW [244 total miles]
                     ASOS......................9.4
                     DAVIS #1.................10.1 NNW  
                     DAVIS #2.................10.3 NNW
                     RMY.......................9.7 NNW
                     VECTOR...................10.3

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M.......0.02  DEPARTURE....-0.12
                             ASOS.............0.03
TOTAL PRECIPITATION FOR THE MONTH.............3.53  DEPARTURE....+0.73
                             ASOS.............3.42
TOTAL PRECIPITATION FOR THE YEAR.............13.70  DEPARTURE....-3.09
                              ASOS...........13.93

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M.........TRACE  DEPARTURE.....-0.1
TOTAL SNOWFALL FOR THE MONTH ..................3.6  DEPARTURE.....+1.2
TOTAL SNOWFALL FOR THE SEASON.................76.2  DEPARTURE....+14.6


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   56/30/43/+2/0.89/T/000/00        44 NW   AERO 51 NW   RMY 49
04/02   37/24/31/-10/0.00/0.0/614/80     28 NW   AERO 32 NNW  RMY 30
04/03   48/23/36/-6/0.00/0.0/755/98      24 NW   AERO 25 NW   RMY 26
04/04   58/33/46/+4/0.00/0.0/734/95      38 NNW  AERO 41 NNW  RMY 41
04/05   57/41/49/+6/T/T/031/04           41 NNW  AERO 48 NNW  RMY 50
04/06   61/40/51/+8/0.00/0.0/412/53      26 NNW  AERO 25 NNW  RMY 31
04/07   57/41/49/+6/0.00/0.0/391/50      23 ENE  AERO 21 ENE  RMY 22
04/08   59/43/51/+7/0.00/0.0/745/95      22 ENE  AERO 22 ENE  RMY 24
04/09   69/42/56/+12/0.00/0.0/707/90     24 S    AERO  M   M  RMY 26
04/10   75/43/59/+14/0.00/0.0/576/73     26 SSW  AERO 28 SSW  RMY 30
04/11   53/40/47/+2/T/0.0/000/00         33 ENE  AERO 33 ENE  RMY 34
04/12   46/37/42/-3/0.05/0.0/000/00      36 ENE  AERO 37 ENE  RMY 41
04/13   56/37/47/+1/T/0.0/.../..         31 NE   AERO 30 NE   RMY 33
04/14   56/42/49/+3/0.00/0.0/.../..      22 ESE  AERO 23 ESE  RMY 22
04/15   51/37/44/-3/.../0.0/.../..       26 ESE  AERO 25 ESE  RMY 28
04/16   39/31/35/-12/..../3.6/.../..     48 NNW  AERO 58 NNW  RMY 58
04/17   45/34/40/-7/..../T/.../..        27 NNW  AERO 30 NNW  RMY 29

04/18   The low since midnight is 34F, the daily normal low is 39F


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

RECORDS FOR APRIL 18
HIGH 92 IN 1976
LOW 23 1887
PRECIP 1.48 IN 1954
SNOWFALL 4.3 IN. IN 2020
PEAK GUST 59 MPH S IN 1982

RECORDS FOR APRIL 19
HIGH 94 IN 1976 [RECORD FOR MONTH]
LOW 21 IN 1890
PRECIP 1.71 IN 1969
SNOWFALL 1.3 IN. IN 1967
PEAK GUST 66 MPH E IN 1984

TODAY'S REPORT PREPARED BY: Benjamin Turner