Sunday, May 12, 2019

| May 12, 2019 | Reply

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, MAY 12, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

RAINY, COLD DAY WITH LOW VISIBILITY…

After a beautiful warm day yesterday, today’s weather
is just the opposite. Temperatures have been dropping
since midnight, with a high so far of 50F at midnight,
and a low of 40F between 10AM and 1PM. Humidity has increased
with cloud cover, and overcast conditions have been observed
since around 6 AM. Showers today have brought a total of
0.30 inches of rain, all falling after 6 o’clock this
morning. Visibility has remained at 20 miles throughout
the duration of the day, with distant fog present at
each observation.

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) 2.57 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: Light rain, distant fog in all directions,
overcast stratus
Temperature: 42F; Dew Point: 36F; Wind: ENE at 8G18 kts
Sea-level pressure: 30.10 ins. Hg, rising, then more slowly
Visibility: 20 miles, distant fog
6-hr Max temp: 50F
6-hr Min temp: 42F
24-hr Precip: 0.03 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 E20 OVC 20R-F 193/42/36/0708G18/010/ R-CTD DSNT
FOG ALQDS/ 8/6// 51014 70003 10050 20042

10 A.M.
Weather: Light rain, distant fog in all directions,
overcast stratus
Temperature: 40F; Dew Point: 39F; Wind: E at 6 kts
Sea-level pressure: 30.09 ins. Hg, rising then steady
Visibility: 20 miles, distant fog
3-hr Precip: 0.14 ins.
BHO SA 1455 E20 OVC 20R-F 191/40/39/0906/009/ R-CTD DSNT FOG
ALQDS/ 8/6// 55002 6014/

1 P.M.
Weather: Light rain, distant fog in all directions,
overcast stratus
Temperature: 40F; Dew Point: 39F; Wind: E at 4 kts,
Wind: Light
Sea-level pressure: 30.03 ins. Hg, falling, then more slowly
Visibility: 20 miles, distant fog
6-hr Max temp: 42F
6-hr Min temp: 40F
6-hr Precip: 0.27 ins.
BHO SA 1755 E20 OVC 20R-F 169/40/39/0804/003/ R-CTD DSNT FOG
ALQDS WND LGT/ 8/6// 56022 60027/ 10042 20040

SUMMARY FOR SATURDAY, MAY 11, 2019

TEMPERATURE (DEGREES F)
MAX…..68   NORMAL…..65
MIN…..50   NORMAL…..46
MEAN….59   NORMAL…..56

DEPARTURE FROM 30-YEAR NORMAL……………………+3
TOTAL DEPARTURE FOR THE MONTH…………………..-24 [-2.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………6   DEPARTURE………-4
TOTAL HEATING UNITS FOR THE MONTH………….142   DEPARTURE……..+19
TOTAL HEATING UNITS FOR THE SEASON………..6043   DEPARTURE…….-115
TOTAL HEATING UNITS LAST SEASON TO DATE……5741   DIFFERENCE……+302

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..26 NW  AT 7:33 A.M.
AERO……………………..M M   AT N/A
ASOS…………………….18 NW  AT 7:35 A.M.
DAVIS……………………37 S   AT 9:13 A.M.  RMY 28
FASTEST MILE FOR YESTERDAY………………….19 NW  AT 8:11 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….27 NNW AT 9:14 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………19 W   AT 8:03 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..10.7 NW
ASOS…………………..10.8
DAVIS………………….11.0 W [281 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.03  DEPARTURE…….-0.10
ASOS…………..0.01
TOTAL PRECIPITATION FOR THE MONTH……….0.51  DEPARTURE…….-0.83
ASOS…………..0.46
TOTAL PRECIPITATION FOR THE YEAR……….21.69  DEPARTURE…….+1.70
ASOS………….21.67

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/…./0.0/605/79           29 S   AERO 25 S   RMY 31
04/03 62/35/49/+7/…./0.0/484/63           54 W   AERO 58 W   RMY 56
04/04 50/34/42/0/…./0.0/717/93            46 W   AERO 41 W   RMY N/A
04/05 47/27/37/-6/…./0.0/341/44           23 SSW AERO 17 SSW RMY 23
04/06 64/32/48/+5/…./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/…./0.0/000/00           35 SSW AERO 29 SSW RMY 39
04/13 71/54/63/+17/…./0.0/167/21          38 SSW AERO 32 SSW RMY N/A
04/14 71/51/61/+15/…./0.0/224/28          25 S   AERO 18 S   RMY N/A
04/15 67/40/54/+7/…./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/+3/0.00/0.0/000/00           44 S   AERO 44 S   RMY 50
04/19 71/58/65/+17/…./0.0/049/06          47 SSW AERO 51 SSW RMY 52
04/20 68/60/64/+15/…./0.0/000/00          50 SSW AERO 54 SSW RMY 52
04/21 68/51/60/+11/…./0.0/123/15          35 S   AERO 35 S   RMY N/A
04/22 53/45/49/0/…./0.0/000/00            35 NNE AERO 32 NNE RMY 35
04/23 52/44/48/-2/…./0.0/041/05           30 NNE AERO 26 NNE RMY N/A
04/24 65/44/55/+5/…./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/…./0.0/000/00           35 ESE AERO 30 W   RMY 33
04/27 54/39/47/-4/…./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/+3/6/0/…/…/..            26 NW  AERO M  M    RMY N/A

05/12 Low temp since midnight is 40F; normal low is 47F

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

RECORDS FOR MAY 12
HIGH 88F IN 2001
LOW 29F IN 1907
PRECIP 1.49 INCHES IN 1968
PEAK GUST 76 MPH S IN 1974

RECORDS FOR MAY 13
HIGH 85F IN 1947
LOW 35F IN 1914, 2005
PRECIP 2.39 INCHES IN 2006
PEAK GUST 49 MPH NNW IN 1965

TODAY’S REPORT PREPARED BY: Samantha Richard

Category: Daily Discussions

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