Wednesday, May 15, 2019

| May 15, 2019 | Reply

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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 15, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

MOSTLY CLOUDY AND COOL WITH GOOD VISIBILITY
ATOP GREAT BLUE HILL….

Last night’s rain left 0.15 inches in the gauge
at the 7 A.M. observation. Conditions have become
gradually drier, with a humidity of 50% after noon.
Visibility has remained 80 miles throughout the day.
Wind is northwesterly with an average speed of 15 mph
and a peak gust of 25 mph. Cloudy skies and cold air
advection from the northwest have continued to keep
temperatures below seasonal averages. The high so far
today is 58F, 9 degrees below the normal maximum of
67F. The low since midnight is 40F, 7 degrees below
the normal daily minimum of 47F.

PRELIMINARY STATS FOR APRIL 2019

TEMPERATURE, Deg. F
Avg. Max. 57.2 [+1.5]
Avg. Min. 39.3 [+1.6]
Mean      48.3 [+1.6]
24-hour corrected mean: 47.3
Max. for month: 71F on the 13th, 14th, and 19th
Min. for month: 27F on the 2nd and 5th

HEATING DEGREE DAYS
Total heating units:    496 [-55]
Total for the season:  5901 [-134]
Total for last season: 5693

PRECIPITATION, Inches
Total: 8.14 [+3.59]
Greatest in 24 hrs: 3.00 ins. on the 22nd-23rd

SNOWFALL, Inches
Total: Trace [-3.0]
Greatest in 24 hrs: Trace on the 10th

WIND, mph
Avg. uncorrected wind speed: 13.2
Avg. corrected wind speed: 13.6
Prevailing wind direction: S at 15%
Peak gust and direction: 54 W on 3rd

SUNSHINE:
Campbell-Stokes card minutes: 8238 minutes of possible 23250 or 35%
Astronomical total minutes:   8543 minutes of possible 24086 or 35%

BHO Greatest April Precipitation, inches (1886-2019):

1) 10.37 in 1987
2)  9.38 in 2004
3)  8.71 in 1929
4)  8.68 in 2007
5)  8.53 in 1904
6)  8.14 in 2019
7)  7.57 in 1935
7.57 in 1983
9)  7.31 in 1901

The calendar day rainfall on Monday, 4/22, was more than
two and a half inches, which made it one of the wettest
calendar days ever observed in April. The finalized
amount for the day is now available.

BHO Greatest April Calendar Day Precipitation, inches (1886-2019):

1) 3.47 on April 1,  2004
2) 3.18 on April 21, 1991
3) 2.63 on April 16, 2018
4) 2.60 on April 22, 2019
5) 2.51 on April 24, 1898
2.51 on April 13, 2004
6) 2.45 on April 16, 1929
7) 2.41 on April 28, 1904
8) 2.40 on April 10, 1935

BHO Lowest April Sunshine, hours (1886-2019):

1)  82.6 in 1901  [21%]
2) 121.1 in 1987  [31%]
3) 121.7 in 1988  [31%]
4) 131.6 in 1983  [34%]
5) 132.2 in 1921  [34%]
6) 137.3 in 2019  [35%]
7) 138.1 in 1939  [36%]
8) 140.7 in 1955  [36%]
9) 141.1 in 2000  [36%]

Today’s Observations:

7 A.M.
Weather: Scattered cumulus, broken altocumulus,
broken cirrus
Temperature: 44F; Dew Point: 42F; Wind: WNW at 10G12 kts
Sea-level pressure: 29.79 ins. Hg, falling then rising
Visibility: 40 miles
6-hr Max temp: 44F
6-hr Min temp: 40F
24-hr Precip: 0.15 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 40 SCT E110 BKN 250 BKN 80 088/44/42/
3010G12/979/ 8/182 70015 50002 10044 20040

10 A.M.
Weather: Broken cumulus
Temperature: 50F; Dew Point: 40F; Wind: NW at 9G18 kts
Sea-level pressure: 29.78 ins. Hg, falling steadily
Visibility: 80 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 E40 BKN 80 085/50/40/3109G18/978/ 8/100
56003

1 P.M.
Weather: Broken cumulus
Temperature: 56F; Dew Point: 38F; Wind: NW at 9G17 kts
Sea-level pressure: 29.76 ins. Hg, falling steadily
Visibility: 80 miles
6-hr Max temp: 58F
6-hr Min temp: 44F
6-hr Precip: 0.00 ins.
BHO SA 1755 E50 BKN 80 080/56/38/3209G17/976/ 8/100
58005 10058 20044

SUMMARY FOR TUESDAY, MAY 14, 2019

TEMPERATURE (DEGREES F)
MAX…..44   NORMAL…..66
MIN…..38   NORMAL…..47
MEAN….41   NORMAL…..57

DEPARTURE FROM 30-YEAR NORMAL…………………..-16
TOTAL DEPARTURE FOR THE MONTH…………………..-64 [-4.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..24   DEPARTURE……..+16
TOTAL HEATING UNITS FOR THE MONTH………….208   DEPARTURE……..+57
TOTAL HEATING UNITS FOR THE SEASON………..6109   DEPARTURE……..-77
TOTAL HEATING UNITS LAST SEASON TO DATE……5775   DIFFERENCE……+334

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..26 NNE AT 11:03 A.M.
AERO……………………..M M   AT N/A
ASOS…………………….26 NE  AT 10:18 A.M.
DAVIS……………………25 ENE AT 12:50 A.M.  RMY 25
FASTEST MILE FOR YESTERDAY………………….18 NNE AT 11:04 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….20 NE  AT 11:04 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………18 NNE AT 11:04 A.M.
AVERAGE WIND SPEED AND DIRECTION……………8.6 NNE
ASOS……………………8.8
DAVIS…………………..8.8 NE [36 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.15  DEPARTURE…….+0.03
ASOS…………..0.13
TOTAL PRECIPITATION FOR THE MONTH……….2.44  DEPARTURE…….+0.73
ASOS…………..2.37
TOTAL PRECIPITATION FOR THE YEAR……….23.62  DEPARTURE…….+3.36
ASOS………….23.58

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 45/29/37/-4/0.00/0.0/748/98           40 WNW AERO 37 W   RMY 42
04/02 50/27/39/-2/0.08/0.0/605/79           29 S   AERO 25 S   RMY 31
04/03 62/35/49/+7/0.36/0.0/484/63           54 W   AERO 58 W   RMY 56
04/04 50/34/42/0/0.00/0.0/717/93            46 W   AERO 41 W   RMY N/A
04/05 47/27/37/-6/0.10/0.0/341/44           23 SSW AERO 17 SSW RMY 23
04/06 64/32/48/+5/0.12/0.0/536/69           24 NW  AERO 18 W   RMY 26
04/07 66/41/54/+11/0.00/0.0/320/41          24 S   AERO 18 S   RMY 25
04/08 48/34/41/-3/0.49/0.0/000/00           25 NE  AERO 20 NE  RMY 26
04/09 40/32/36/-8/0.08/0.0/000/00           23 NE  AERO 16 N   RMY 25
04/10 43/30/37/-8/T/T/000/00                32 NW  AERO 26 NW  RMY 36
04/11 51/29/40/-5/0.00/0.0/403/51           23 NW  AERO 18 NW  RMY N/A
04/12 53/38/46/+1/0.15/0.0/000/00           35 SSW AERO 29 SSW RMY 39
04/13 71/54/63/+17/0.38/0.0/167/21          38 SSW AERO 32 SSW RMY N/A
04/14 71/51/61/+15/0.15/0.0/224/28          25 S   AERO 18 S   RMY N/A
04/15 67/40/54/+7/0.93/0.0/168/21           46 W   AERO 52 W   RMY 50
04/16 58/37/48/+1/0.00/0.0/805/100          46 W   AERO 44 W   RMY 44
04/17 62/36/49/+2/0.00/0.0/807/100          26 ESE AERO 25 S   RMY 28
04/18 63/39/51/+3/T/0.0/000/00              44 S   AERO 44 S   RMY 50
04/19 71/58/65/+17/0.03/0.0/049/06          47 SSW AERO 51 SSW RMY 52
04/20 68/60/64/+15/0.46/0.0/000/00          50 SSW AERO 54 SSW RMY 52
04/21 68/51/60/+11/0.06/0.0/123/15          35 S   AERO 35 S   RMY N/A
04/22 53/45/49/0/2.60/0.0/000/00            35 NNE AERO 32 NNE RMY 35
04/23 52/44/48/-2/0.42/0.0/041/05           30 NNE AERO 26 NNE RMY N/A
04/24 65/44/55/+5/0.02/0.0/438/53           29 WNW AERO 29 WNW RMY 30
04/25 61/39/50/0/0.00/0.0/696/84            22 S   AERO 22 S   RMY 21
04/26 53/42/48/-3/0.84/0.0/000/00           35 ESE AERO 30 W   RMY 33
04/27 54/39/47/-4/0.62/0.0/100/12           41 W   AERO 44 W   RMY 47
04/28 51/38/45/-7/0.08/0.0/159/19           28 W   AERO 28 W   RMY N/A
04/29 60/34/47/-5/0.00/0.0/612/73           23 NW  AERO 24 WNW RMY 24
04/30 48/40/44/-8/0.17/0.0/000/00           26 NW  AERO 23 NW  RMY 25

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 57/40/49/-4/0.00/0.0/…/..           21 S   AERO 21 SSE  RMY 21
05/02 45/41/43/-10/0.02/0.0/…/..          21 NE  AERO 21 SSW  RMY 20
05/03 60/43/52/-1/…./…/…/..           23 S   AERO 23 S    RMY 22
05/04 54/46/50/-4/…./…/…/..           14 ENE AERO 14 ENE  RMY 17
05/05 52/44/48/-6/0.00/0.0/…/..           18 NE  AERO 20 NE   RMY N/A
05/06 58/44/51/-3/…./0.0/…/..           25 NE  AERO 26 ENE  RMY 24
05/07 72/41/57/+2/0.12/0.0/…/..           30 S   AERO 29 S    RMY 30
05/08 67/48/58/+3/0.00/0.0/…/..           20 NE  AERO 20 NE   RMY 19
05/09 60/43/52/-3/0.00/0.0/…/..           21 SE  AERO 21 E    RMY 22
05/10 61/46/54/-1/0.16/0.0/…/..           35 S   AERO 37 S    RMY 37
05/11 68/50/59/+3/…./…/…/.. 26 NW  AERO M  M    RMY N/A
05/12 50/36/43/-13/0.68/T/…/..          30 ENE AERO M  M    RMY N/A
05/13 52/38/45/-11/…./…/…/..          35 E   AERO M  M    RMY 34
05/14 44/38/41/-16/…./…/…/..          26 NNE AERO M  M    RMY 25

05/15 Low temp since midnight is 40F; normal low is 48F

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

RECORDS FOR MAY 15
HIGH 93F IN 1900
LOW 36F IN 1947,1985
PRECIP 1.63 INCHES IN 1978
PEAK GUST 53e MPH NE IN 1978, W 2002

RECORDS FOR MAY 16
HIGH 90F IN 1951
LOW 30F IN 1936
PRECIP 2.63 INCHES IN 1954
PEAK GUST 56e MPH NW IN 1952

TODAY’S REPORT PREPARED BY: Benjamin Turner

Category: Daily Discussions

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