Saturday, May 18, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, MAY 18, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

WARM SUNNY DAY ON TOP OF GREAT BLUE HILL….

Today we observed clear skies in the morning with
a cirrostratus layer becoming more prevalent in the
afternoon. Wind has decreased throughout the day
with a light variable wind between observations.
The high so far today is 70F, 3 degrees above the
normal maximum of 67F. The low since midnight is 49F,
1 degree above the normal daily minimum of 48F.

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: Clear, few cirrostratus
Temperature: 53F; Dew Point: 46F; Wind: NW at 9G16 kts,
Sea-level pressure: 29.94 ins. Hg, rising, then more slowly
Visibility: 60 miles, distant haze
6-hr Max temp: 64F
6-hr Min temp: 49F
24-hr Precip: 0.07 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 CLR 60 140/53/46/3209G16/994/ FEW AS ALQDS
DSNT HZ ALQDS/ 8/005 70007 51026 10064 20049

10 A.M.
Weather: Scattered cirrostratus
Temperature: 62F; Dew Point: 38F; Wind: NNW at 8 kts,
Sea-level pressure: 29.99 ins. Hg, rising, then more slowly
Visibility: 80 miles,
3-hr Precip: 0.00 ins.
BHO SA 1455 250 SCT 80 156/62/38/3308/999/ 8/008 51016

1 P.M.
Weather: Scattered cirrostratus
Temperature: 69F; Dew Point: 40F; Wind: NNW at 6 kts,
Wind: Light and variable
Sea-level pressure: 29.97 ins. Hg, rising, then more slowly
Visibility: 80 miles,
6-hr Max temp: 70F
6-hr Min temp: 53F
6-hr Precip: 0.00 ins.
BHO SA 1755 250 SCT 80 152/69/40/3306/997/ 8/008 51004
10070 20053

SUMMARY FOR FRIDAY, MAY 17, 2019

TEMPERATURE (DEGREES F)
MAX…..64   NORMAL…..66
MIN…..49   NORMAL…..48
MEAN….57   NORMAL…..57

DEPARTURE FROM 30-YEAR NORMAL…………………….0
TOTAL DEPARTURE FOR THE MONTH…………………..-72 [-4.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………8   DEPARTURE………+8
TOTAL HEATING UNITS FOR THE MONTH………….240   DEPARTURE……..+63
TOTAL HEATING UNITS FOR THE SEASON………..6141   DEPARTURE……..-71
TOTAL HEATING UNITS LAST SEASON TO DATE……5790   DIFFERENCE……+351

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..19 WNW AT 1:16 P.M.
AERO…………………….21 WNW AT 1:09 P.M.
ASOS…………………….23 W   AT 1:16 P.M.
DAVIS……………………23 S   AT 6:51 P.M.  RMY 25
FASTEST MILE FOR YESTERDAY………………….19 W   AT 10:32 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….18 W   AT 10:32 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………19 SW  AT 10:31 P.M.
AVERAGE WIND SPEED AND DIRECTION……………8.8 S
ASOS……………………8.9
DAVIS…………………..9.3 S [186 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.07  DEPARTURE…….-0.13
ASOS…………..0.08
TOTAL PRECIPITATION FOR THE MONTH……….2.51  DEPARTURE…….+0.43
ASOS…………..2.45
TOTAL PRECIPITATION FOR THE YEAR……….23.69  DEPARTURE…….+3.06
ASOS………….23.66

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/-2/0.08/0.0/605/79           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 58/40/49/-8/…./…/…/..           28 NW  AERO M  M    RMY 28
05/16 68/46/57/0/…./…/…/..            17 NW  AERO M  M    RMY 19
05/17 64/49/57/0/…./…/…/.. 22 WNW AERO 21 WNW  RMY 25

05/18 Low temp since midnight is 49F; normal low is 48F

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: Nicholas Rousseau