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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 11, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

RAIN SHOWERS DEPART OVERNIGHT...BEAUTIFUL SPRING DAY TODAY...

A rain shower before midnight brought 0.16 inches of rain in under
an hour. A few low clouds lingered early this morning, though these
moved out during the morning, leaving only a few high clouds and a
brilliant, sunny day. It has been breezy with frequent gusts to
20-25 mph. The visibility climbed quickly from 45 miles at 7 AM
to 75 miles by mid-morning as drier air moved in and the dew point
dropped to the upper 30s by early afternoon.  The high temperature 
so far today is 67F, 2 degrees above the daily normal maximum of 65F. 
The low since midnight is 52F, 6 degrees warmer than the normal 
minimum of 46F.


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: Scattered stratocumulus, scattered altocumulus,
thin scattered cirrus, few lower stratocumulus SW-NNE
Temperature: 54F; Dew Point: 42F; Wind: WNW at 10 kts
Sea-level pressure: 29.96 ins. Hg, rising, then more slowly
Visibility: 45 miles, visibility WNW-NW 50, SE-S 30, hazy
6-hr Max temp: 58F
6-hr Min temp: 52F
24-hr Precip: 0.16 ins. 
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins. 
BHO SA 1155 65 SCT 85 SCT 250 –SCT 45 145/54/42/3010/996/ FEW LWR 
SC SW-NNE VSBY WNW-NW 50 SE-S 30 HAZY/ 8/531 51016 6000/ 70016 
10058 20052

10 A.M.
Weather: Scattered stratocumulus, scattered cirrus
Temperature: 61F; Dew Point: 40F; Wind: NW at 10G16 kts
Wind: Direction variable W-NNW
Sea-level pressure: 29.98 ins. Hg, rising, then more rapidly
Visibility: 75 miles
3-hr Precip: 0.00 ins. 
BHO SA 1455 35 SCT 250 SCT 75 151/61/40/3110G16/998/ WND 28V34/ 
8/101 53006

1 P.M.
Weather: Thin scattered cirrus, few cumulus distant W and SE
Temperature: 66F; Dew Point: 39F; Wind: NW at 11G28 kts
Sea-level pressure: 29.96 ins. Hg, falling, then more slowly
Visibility: 75 miles
6-hr Max temp: 67F
6-hr Min temp: 54F
6-hr Precip: 0.00 ins. 
BHO SA 1755 250 –SCT 75 144/66/39/3111G18/996/ FEW CU DSNT W AND 
DSNT SE/ 8/101 56007 10067 20054

SUMMARY FOR FRIDAY, MAY 10, 2019 

TEMPERATURE (DEGREES F)
MAX.....61   NORMAL.....65
MIN.....46   NORMAL.....46
MEAN....54   NORMAL.....55

DEPARTURE FROM 30-YEAR NORMAL........................-1
TOTAL DEPARTURE FOR THE MONTH.......................-27 [-2.9 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............11   DEPARTURE.........+1
TOTAL HEATING UNITS FOR THE MONTH.............136   DEPARTURE........+23
TOTAL HEATING UNITS FOR THE SEASON...........6037   DEPARTURE.......-111
TOTAL HEATING UNITS LAST SEASON TO DATE......5737   DIFFERENCE......+300

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................35 S   AT  3:14 P.M. *
                   AERO.........................37 S   AT  2:44 P.M.
                   ASOS.........................36 S   AT  2:23 P.M. 
                   DAVIS........................37 S   AT 10:51 A.M.  RMY 37
FASTEST MILE FOR YESTERDAY......................26 S   AT  2:23 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE...................26 S   AT  2:43 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE..................26 SSE AT  2:43 P.M.
AVERAGE WIND SPEED AND DIRECTION..............15.4 S
                   ASOS.......................15.6
                   DAVIS......................15.2 S [171 deg.]
* Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.16  DEPARTURE.......+0.04
                         ASOS..............0.17
TOTAL PRECIPITATION FOR THE MONTH..........0.48  DEPARTURE.......-0.74
                         ASOS..............0.45
TOTAL PRECIPITATION FOR THE YEAR..........21.66  DEPARTURE.......+1.89
                         ASOS.............21.66


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 Low temp since midnight is 52F; normal low is 46F


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

RECORDS FOR MAY 11
HIGH 90F IN 1993
LOW 28F IN 1900
PRE 1.28 INS IN 1957
SNOW 1.0 INS IN 1907 (LATEST MEASURABLE SNOW ON RECORD)
PEAK GUST 75e MPH NW IN 1945

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

TODAY'S REPORT PREPARED BY: Mike Iacono