Monday, May 18, 2020

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, MAY 18, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME

OVERCAST AND COOL WITH LIGHT ONSHORE WIND….

It’s been a quiet day today under cloudy skies. A few
very light rain showers moved through this morning, but
only amounted to a trace. Otherwise a light wind that
started out of the west, gradually veered to the northeast
helping to keep temperatures on the cool side.

Visibility has been limited to only 50 miles today.

The high so far today is 58F, this is 9 degrees below the
daily normal high of 67F. The low since midnight is 49F,
which is a degree above the daily normal low of 48F.

Today’s Observations:

7 A.M.
Weather: Overcast altostratus
Temperature: 55F; Dew Point: 46F; Relative Humidity: 72%
Wind: N at 8 kts
Sea-level pressure: 30.21 ins. Hg: rising, then more slowly
Visibility: 50 miles
6-hr Max temp: 55F
6-hr Min temp: 49F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
BHO SA 1155 E90 OVC 50 231/55/46/3508/021/ FEW BINOVC SE-S/
8/02/ 51009 10055 20049

10 A.M.
Weather: Overcast altostratus
Temperature: 53F; Dew Point: 44F; Relative Humidity: 70%
Wind: NE at 8G14 kts
Sea-level pressure: 30.22 ins. Hg: steady, then rising
Visibility: 50 miles
3-hr Precip: Trace
3-hr Snowfall: 0.0 ins.
BHO SA 1455 E85 OVC 50RW- 234/53/44/0508G14/022/ PCPN VRY LGT
RB20/ 8/02/ 53003 6000

1 P.M.
Weather: Broken altostratus, overcast dense cirrus, few breaks
in overcast distant NNW-NE
Temperature: 58F; Dew Point: 42F; Relative Humidity: 55%
Wind: NE at 7 kts
Sea-level pressure: 30.22 ins. Hg: rising then falling
Visibility: 50 miles
6-hr Max temp: 58F
6-hr Min temp: 53F
6-hr Precip: Trace
6-hr Snowfall: 0.0 ins.
BHO SA 1755 E130 BKN 180 OVC 50 234/58/42/0507/022/
FEW BINOVC DSNT NNW-NE/ 8/022 58000 10058 20053

SUMMARY FOR SUNDAY, MAY 17, 2020

TEMPERATURE (DEGREES F)
MAX…..67   NORMAL…..67
MIN…..47   NORMAL…..48
MEAN….57   NORMAL…..57

DEPARTURE FROM 30-YEAR NORMAL………………. 0
TOTAL DEPARTURE FOR THE MONTH………………-37 [-2.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………… 8  DEPARTURE…….. 0
TOTAL HEATING UNITS FOR THE MONTH…………..207  DEPARTURE…….+30
TOTAL HEATING UNITS FOR THE SEASON…………5728  DEPARTURE……-484
TOTAL HEATING UNITS LAST SEASON TO DATE…….6140  DEPARTURE……-412

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………….0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH…………….2  DEPARTURE……..-5
TOTAL COOLING UNITS FOR THE SEASON……………2  DEPARTURE……..-7
TOTAL COOLING UNITS LAST SEASON TO DATE……….0  DEPARTURE……..+2

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..22 S   AT  8:27 P.M.
AERO…………………….MM MMM AT MM:MM M.M.
ASOS…………………….21 S   AT  8:46 P.M.
DAVIS……………………21 S   AT  5:41 P.M. RMY 21
FASTEST MILE FOR YESTERDAY………………….15 S   AT  8:48 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….16 S   AT  8:49 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………15 S   AT  7:59 P.M.
AVERAGE WIND SPEED AND DIRECTION……………. 8.0 SSW
ASOS……………………. 8.3
DAVIS…………………… 7.8 SSW [203 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE……-0.13
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….2.55  DEPARTURE……+0.47
ASOS…………..2.54
TOTAL PRECIPITATION FOR THE YEAR……….19.59  DEPARTURE……-1.04
ASOS………….20.04

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE MONTH…………..Trace  DEPARTURE……..0.0
TOTAL SNOWFALL FOR THE SEASON…………..31.9  DEPARTURE……-30.8

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

05/01  64/52/58/+5/…./0.0/000/00         46 SSE  AERO 44 SSE RMY N/A
05/02  70/42/56/+3/…./0.0/729/86         41 NW   AERO 40 NW  RMY N/A
05/03  78/55/67/+14/0.00/0.0/613/72        35 SSW  AERO 35 SSW RMY 36
05/04  72/45/59/+5/T/0.0/247/29            37 NW   AERO 40 WNW RMY 39
05/05  60/40/50/-4/0.00/0.0/821/96         31 NW   AERO 32 NW  RMY N/A
05/06  57/38/48/-6/T/0.0/498/58            24 ESE  AERO 22 ENE RMY 22
05/07  63/37/50/-5/0.00/0.0/576/67         30 WSW  AERO 29 WSW RMY N/A
05/08  57/40/49/-6/…./0.0/328/38         31 W    AERO 32 W   RMY N/A
05/09  44/32/38/-17/…./T/484/56          52 W    AERO 53 W   RMY 54
05/10  59/31/45/-10/0.00/0.0/763/88        46 W    AERO 46 W   RMY 49
05/11  65/43/54/-2/0.22/0.0/…/..         39 S    AERO 43 S   RMY 41
05/12  55/37/46/-10/0.00/0.0/…/..        37 W    AERO 37 W   RMY 37
05/13  59/32/46/-10/0.00/0.0/…/..        37 WNW  AERO 37 WNW RMY 38
05/14  70/40/55/-2/0.00/0.0/…/..         29 W    AERO 26 W   RMY 27
05/15  78/50/64/+7/…./0.0/…/..         40 WSW  AERO 40 WSW RMY 43
05/16  69/47/58/+1/…./0.0/…/..         31 NW   AERO 31 NW  RMY 32
05/17  67/47/57/0/0.00/0.0/…/..          22 SSW  AERO N/A    RMY 21

05/18 The low since midnight is 49F, the daily normal low is 48F

DAILY RECORDS FOR MAY 2020

5/13/2020: NEW RECORD LOW OF 32F, REPLACING 35F SET IN
1914 AND 2005

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

RECORDS FOR MAY 18
HIGH 96F IN 2017(RECORD FOR MAY)
LOW 35F IN 2002
PRECIP 1.93 INS IN 2007
SNOW TRACE IN 2002 (Ice pellets)
PEAK GUST 64 MPH SSW IN 2000

RECORDS FOR MAY 19
HIGH 91F IN 1962
LOW 34F IN 2002
PRECIP 1.54 INCHES IN 1900
PEAK GUST 58 MPH NW IN 1964

TODAY’S REPORT PREPARED BY: Matt Douglas