Tuesday, May 21, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, MAY 21, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

GUSTY WINDS AND SEASONABLE CONDITIONS ON TOP OF THE GREAT BLUE HILL

At the 7 A.M. observation, 0.35 inches was observed in the rain gauge
from passing thunderstorms on the afternoon of the 20th. Winds have
been gusty throughout the day with a peak gust of 38 miles per hour
reported by the 420c. Skis remained partly cloudy and visibility 75
miles through the 1 P.M. observation. The high so far today is 67F,
1 degrees below the normal maximum of 68F. The low since midnight is
51 F, 3 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: Scattered cumulus, few altocumulus
Temperature: 53F; Dew Point: 43F; Wind: WNW at 21G29 kts,
Sea-level pressure: 29.76 ins. Hg, falling then rising
Visibility: 75 miles
6-hr Max temp: 85F
6-hr Min temp: 52F
24-hr Precip: 0.35 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 05 SCT 75 080/53/43/2921G29/976/ FEW AC NE-E
PK WND 2930/55 8/100 53014 70035 10085 20052

10 A.M.
Weather: Scattered cumulus, few altocumulus
Temperature: 62F; Dew Point: 50F; Wind: WSW at 19G28 kts,
Sea-level pressure: 29.75 ins. Hg, rising then falling
Visibility: 75 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 52 SCT 75 077/62/50/2919G28/975/ FEW AC ALQDS
PK WND 2928/20 8/100 58003

1 P.M.
Weather: Scattered cirrostratus, few cumulus
Temperature: 66F; Dew Point: 36F; Wind: WNW at 15G28 kts
Sea-level pressure: 29.75 ins. Hg, rising then falling
Visibility: 75 miles,
6-hr Max temp: 67F
6-hr Min temp: 60F
6-hr Precip: 0.00 ins.
BHO SA 1755 250 SCT 75 077/66/36/3015G28/975/ FEW CU ALQDS
PK WND 3034/44 8/008 50004 10067 20060

SUMMARY FOR MONDAY, MAY 20, 2019

TEMPERATURE (DEGREES F)
MAX…..69   NORMAL…..68
MIN…..50   NORMAL…..49
MEAN….60   NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL……………………-8
TOTAL DEPARTURE FOR THE MONTH…………………..-75 [-3.75 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….0
TOTAL HEATING UNITS FOR THE MONTH………….249   DEPARTURE……..+49
TOTAL HEATING UNITS FOR THE SEASON………..6150   DEPARTURE……..-85
TOTAL HEATING UNITS LAST SEASON TO DATE……5817   DIFFERENCE……+333

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………4   DEPARTURE……….0
TOTAL COOLING UNITS FOR THE MONTH……………4   DEPARTURE………-5
TOTAL COOLING UNITS FOR THE SEASON………….-7   DEPARTURE………11
TOTAL COOLING UNITS LAST SEASON TO DATE……..37   DEPARTURE……..-33

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..35 SW AT 3:03 P.M.
AERO…………………….40 SW AT 3:00 P.M.
ASOS…………………….35 W  AT 3:03 P.M.
DAVIS……………………38 S  AT 3:14 P.M.  RMY 39
FASTEST MILE FOR YESTERDAY………………….26 SW AT 3:01 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….25 W AT 3:03 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………26 WSW AT 3:04 P.M.
AVERAGE WIND SPEED AND DIRECTION……………14.8 SSW
ASOS……………………13.7
DAVIS…………………..14.5 WSW [204 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.35  DEPARTURE…….0.01
ASOS…………..0.37
TOTAL PRECIPITATION FOR THE MONTH……….3.00  DEPARTURE…….+0.17
ASOS…………..2.82
TOTAL PRECIPITATION FOR THE YEAR……….24.18  DEPARTURE…….+3.15
ASOS………….24.03

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/…/…/..          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 72/49/61/+3/…./…/…/..           26 SSE AERO 25 SSE  RMY 29
05/19 69/50/60/+2/…./…/…/..           39 S   AERO 43 SSE  RMY 42
05/20 85/52/69/11/…./…/…/..    35 SW  AERO 40 SW   RMY 39

5/21 Low temp since midnight is 50F; normal low is 49F

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

RECORDS FOR MAY 20
HIGH 91F IN 1975,1996
LOW 37F IN 1948, 2002
PRECIP 1.65 INCHES IN 1969
PEAK GUST 57 MPH S IN 1963, WNW IN 1982

RECORDS FOR MAY 21
HIGH 92F IN 1921
LOW 35F IN 1907
PRECIP 1.61 INS IN 1954
PEAK GUST 74 MPH WSW IN 2006

TODAY’S REPORT PREPARED BY: Nicholas Rousseau