Monday, April 20, 2020

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, APRIL 20, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

CLOUDY AND COOL, BUT DRY TODAY WITH EXCELLENT VISIBILITY…

What a difference a day makes! After a very nice day
yesterday in which the high reached 60 degrees under
a mostly sunny sky, today has been overcast with a
chilly breeze. Temperatures have only reached the
upper 40s, which occurred late in the morning. Since
then temperatures have actually fallen a bit as the
wind turned onshore this afternoon.

Visibility has been excellent all day despite the cloud
cover, hanging at 70 miles.

Our high temperature so far today is 48F, which is 10
degrees below our daily normal high temperature of 58F.
The low since midnight is 43F, which is 3 degrees above
the daily normal low of 40F.

Today’s Observations:

7 A.M.
Weather: Broken altocumulus, overcast dense cirrus
Temperature: 46F; Dew Point: 34F; Relative Humidity: 62%
Wind: NW at 8 kts
Sea-level pressure: 29.71 ins. Hg: rising, then more slowly
Visibility: 70 miles
6-hr Max temp: 47F
6-hr Min temp: 43F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 E110 BKN 180 OVC 70 061/46/34/3208/971/ FEW BINOVC
DSNT NW-NE FEW SC W-NW-NE SUN DMLY VSBL/ 8/572 51019 10047 20043

10 A.M.
Weather: Scattered altocumulus, overcast dense cirrus
Temperature: 48F; Dew Point: 32F; Relative Humidity: 53%
Wind: N at 8 kts
Sea-level pressure: 29.70 ins. Hg: rising, then falling
Visibility: 70 miles
3-hr Precip:   0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 SCT 120 E180 OVC 70 058/48/32/3608/970/ FEW BINOVC
DSNT W-N FEW SC S-SW SUN DMLY VSBL/ 8/572 55003

1 P.M.
Weather: Overcast dense cirrus
Temperature: 47F; Dew Point: 27F; Relative Humidity: 45%
Wind: ENE at 10G21 kts
Sea-level pressure: 29.64 ins. Hg: falling, then more rapidly
Visibility: 70 miles
6-hr Max temp: 49F
6-hr Min temp: 46F
6-hr Precip:   0.00 ins
6-hr Snowfall: 0.0 ins
BHO SA 1755 E160 OVC 70 038/47/27/0610G21/964/ FEW BINOVC DSNT
W-N SUN DMLY VSBL/ 8/072 58020 10049 20046

SUMMARY FOR SUNDAY, APRIL 19, 2020

TEMPERATURE (DEGREES F)
MAX…..60   NORMAL…..57
MIN…..31   NORMAL…..39
MEAN….46   NORMAL…..48

DEPARTURE FROM 30-YEAR NORMAL………………. -2
TOTAL DEPARTURE FOR THE MONTH……………….-15 [-1.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………19  DEPARTURE……. +2
TOTAL HEATING UNITS FOR THE MONTH…………..403  DEPARTURE…….+14
TOTAL HEATING UNITS FOR THE SEASON…………5276  DEPARTURE……-596
TOTAL HEATING UNITS LAST SEASON TO DATE…….5742  DEPARTURE……-466

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..40 SSW AT  3:43 P.M.
AERO…………………….40 SSW AT  3:43 P.M
ASOS…………………….39 S   AT  3:44 P.M.
DAVIS……………………40 S   AT  3:44 P.M. RMY 41
FASTEST MILE FOR YESTERDAY………………….29 SSW AT  3:44 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….30 SSW AT  3:44 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………29 SSW AT  3:44 P.M.
AVERAGE WIND SPEED AND DIRECTION…………….15.3 SW
ASOS…………………….14.6
DAVIS……………………15.1 WSW [238 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.14
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….5.66  DEPARTURE……+2.58
ASOS…………..5.84
TOTAL PRECIPITATION FOR THE YEAR……….14.99  DEPARTURE……-2.09
ASOS………….15.57

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.1
TOTAL SNOWFALL FOR THE MONTH…………….4.3  DEPARTURE…….+1.7
TOTAL SNOWFALL FOR THE SEASON…………..31.9  DEPARTURE……-30.4

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  42/28/35/-6/0.00/0.0/…/..         28 NE  AERO 28 NE  RMY 30
04/02  46/35/41/0/…/0.0/…/..           39 NW  AER0 40 NW  RMY 41
04/03  42/38/40/-2/…./0.0/…/..         48 NE  AERO 53 NE  RMY 49
04/04  46/36/41/-1/…./0.0/…/..         38 NE  AERO 38 NE  RMY N/A
04/05  55/36/46/+3/T/0.0/…/..            22 S   AERO 21 S   RMY 21
04/06  61/40/51/+8/0.00/0.0/…/..         29 NW  AERO 30 NW  RMY 29
04/07  63/42/53/+10/0.00/0.0/…/..        29 W   AERO 30 W   RMY 28
04/08  50/41/46/+2/…./…/…/..         23 S   AERO 22 S   RMY 22
04/09  47/37/42/-2/…./…/…/..         58 W   AERO 58 W   RMY 56
04/10  47/35/41/-4/0.02/T/…/..           48 W   AERO 50 W   RMY 53
04/11  51/33/42/-3/0.00/0.0/…/..         38 WNW AERO 39 WNW RMY 40
04/12  60/33/47/+2/0.00/0.0/…/..         38 S   AERO 40 S   RMY N/A
04/13  59/50/55/+9/1.42/0.0/…/..         79 S   AERO 83 S   RMY 78
04/14  57/41/49/+3/0.00/0.0/…/..         41 W   AERO 40 W   RMY N/A
04/15  52/36/44/-3/0.02/0.0/…/..         37 W   AERO 36 W   RMY 37
04/16  47/32/40/-7/T/T/…/..              33 WNW AERO 33 WNW RMY 32
04/17  49/29/39/-8/…./…/…/..         41 W   AERO 39 W   RMY 41
04/18  37/31/34/-14/…./4.3/…/..        29 NE  AERO 25 NE  RMY 25
04/19 60/31/46/-2/0.00/0.0/…/.. 40 SSW AERO 40 SSW RMY 41

04/20 The low since midnight is 43F, daily normal minimum is 39F

DAILY RECORDS FOR APRIL 2020

4/13/2020
NEW PEAK GUST OF 79 MPH S, REPLACING THE OLD
RECORD OF 59 MPH SSW IN 1995

4/18/2020
NEW RECORD SNOWFALL OF 4.3 INS, REPLACING
SNOWFALL OF 3.7 IN. IN 1965

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

RECORDS FOR APRIL 20
HIGH 88 IN 1927
LOW 18 IN 1897
PRECIP 1.14 IN 1972
SNOWFALL 2.5 IN. IN 1904, 1972
PEAK GUST 76 MPH WNW IN 1963

RECORDS FOR APRIL 21
HIGH 85 IN 1923
LOW 22 IN 1908
PRECIP 3.18 IN. IN 1991
SNOWFALL 0.8 IN. IN 1947
PEAK GUST 76e MPH NE IN 1940

TODAY’S REPORT PREPARED BY: Matt Douglas