Monday, May 20, 2024

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

MONDAY, MAY 20, 2024
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0418E
SUNSET:  1904E

MORNING CLOUDS GIVING WAY TO AFTERNOON SUNSHINE, MUCH MILDER….

Overcast skies this morning finally gave way to partial sunshine
early this afternoon. As a result of the sun and lighter wind off
the ocean, temperatures are being allowed to warm significantly
today compared to the past few days..

Temperature readings have reached the mid 60s early this afternoon,
which is a considerable difference from the low 50s we were only
able to muster yesterday. As a matter of fact, the high for
yesterday was 15 degrees below expected levels for this time of
year. The dew point remains in the 50s however, so the air mass
still has a decent moisture content within it as represented by
a relative humidity of 73% at 1pm.

The wind is much lighter today than it has been over the past
couple of days. The average speed for the day so far is around 7mph.
The peak gust thus far for the day is only 16mph, which occurred
just before 9am this morning.

Visibility has been gradually improving as the day progresses,
going from around 15-20 miles early this morning upto around 40
miles by early this afternoon.

The maximum temperature so far today is 64F degrees, which is 4
degrees below the normal high of 68F. The minimum temperature since
midnight is 48F degrees, which is 1 degree below the normal low of
49F.

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Today’s Observations:

7 A.M.
Weather: Broken stratus fractus, overcast stratocumulus, few breaks
in overcast distant NNE
Temperature: 53F; Dew Point: 52F; Relative Humidity: 97%
Wind: NNE @ 5 kts, wind light
Sea-level pressure: 1018.8 mb; 30.09 in. Hg: rising, then more rapidly
Visibility: 20 miles, thin fog
6-hr Max temp: 53F
6-hr Min temp: 48F
24-hr Precip:  0.12 inches
BHO SA 1155 E6 BKN 20 OVC 20 188/53/52/0305/009/ FEW BINOVC DSNT
NNE THN F ALQDS WND LGT/ 8/5// 53007 70012 10053 20048

10 A.M.
Weather: Overcast stratocumulus, few lower stratocumulus distant NNE-ESE
Temperature: 58F; Dew Point: 52F; Relative Humidity: 82%
Wind: E @ 7 kts
Sea-level pressure: 1019.1 mb; 30.09 in. Hg: rising, then more slowly
Visibility: 35 miles, hazy
3-hr Precip:  0.00 inches
BHO SA 1455 E12 OVC 35 191/58/52/0807/009/ FEW LWR SC DSNT NNE-ESE
HAZY/ 8/5// 51003

1 P.M.
Weather: Scattered stratocumulus, thin broken cirrus
Temperature: 63F; Dew Point: 54F; Relative Humidity: 73%
Wind: ESE @ 5 kts, wind light
Sea-level pressure: 1018.6 mb; 30.08 in. Hg: rising, then falling
Visibility: 40 miles, hazy
6-hr Max temp: 64F
6-hr Min temp: 53F
6-hr Precip:  0.00 inches
BHO SA 1755 15 SCT E250 -BKN 40 186/63/54/1105/008/ HAZY WND LGT/
8/501 58005 10064 20053

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SUMMARY FOR SUNDAY, MAY 19, 2024

TEMPERATURE (DEGREES F)
MAX…….53   NORMAL…..68
MIN…….48   NORMAL…..49
MEAN……51   NORMAL…..58

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………….-7
TOTAL DEPARTURE FOR THE MONTH……………………-22 [-1.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2023 THRU JUN 2024)
TOTAL HEATING UNITS FOR YESTERDAY……………14  DEPARTURE……..+6
TOTAL HEATING UNITS FOR THE MONTH…………..200  DEPARTURE…….+17
TOTAL HEATING UNITS FOR THE SEASON…………5357  DEPARTURE……-713
TOTAL HEATING UNITS LAST SEASON TO DATE…….5128  DEPARTURE……+229

COOLING DEGREE DAYS (SEASON: JAN 2024 THRU DEC 2024)
TOTAL COOLING UNITS FOR YESTERDAY…………….0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH…………….2  DEPARTURE……..-8
TOTAL COOLING UNITS FOR THE SEASON……………2  DEPARTURE…….-11
TOTAL COOLING UNITS LAST SEASON TO DATE………25  DEPARTURE…….-23

PEAK WIND GUST (MPH):
Note: Instruments designated #1 = Main Tower, #2 = South Tower,
F420C, Contacting, Merlin, and Richards are all Main Tower.
E=Estimated

F420C (Official)……….E30 NE   @  06:17 A.M.
VECTOR #1 (1-Sec)……….30 NE   @  04:37 A.M.
VECTOR #2 (1-Sec)……….29 NE   @  08:59 A.M.
DAVIS #1……………….28 NE   @  04:37 A.M.
DAVIS #2 ………………28 ENE  @  08:59 A.M.
RMY #1 (Instantaneous)…..30 NE   @  04:18 A.M.
RMY #2 (Instantaneous)…..31 NE   @  04:37 A.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)……27      @  06:17 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………18 NE   @  09:20 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..17      @  05:19 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..18      @  05:19 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………18 ENE  @  12:10 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………18 NE   @  05:19 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..17 NE   @  06:49 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..18 NE   @  05:19 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………17      @  06:50 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……11.0 NE [263 total miles] VECTOR #1…………….10.6
VECTOR #2…………….11.1
DAVIS #1……………..11.2 ENE
DAVIS #2……………..11.1 ENE
RMY #1……………….10.4 NE
RMY #2……………….10.8 NE
RICHARDS (C5C)………..10.9

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.12 DEPARTURE…..+0.01
TOTAL PRECIPITATION FOR THE MONTH…………..3.22 DEPARTURE…..+0.96
TOTAL PRECIPITATION FOR THE YEAR (2024)…….28.18 DEPARTURE…..+7.14

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE…….0.0
TOTAL SNOWFALL FOR THE MONTH………………..0.0 DEPARTURE…….0.0
TOTAL SNOWFALL FOR THE SEASON (2023-2024)……26.8 DEPARTURE…..-42.9

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PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN)/SUN(%)/PEAK GUST/VEC1/RMY GUST
PEAK GUST: F420C (Official)
VEC1: Vector #1 1-second gust
RMY:  R.M. Young #1 wind gust recording system (Instantaneous)
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)

5/1   53/42/48/-5/0.06/0.0/177/21         18 ESE VEC1 18 ESE RMY 18
5/2   69/44/57/+3/0.21/0.0/535/63         35 NE  VEC1 36 NE  RMY 35 TSTM
5/3   57/44/51/-3/0.02/0.0/408/48         24 NE  VEC1 24 NE  RMY 25
5/4   55/44/50/-4/0.00/0.0/589/69         22 ENE VEC1 21 NE  RMY 21
5/5   51/42/47/-8/0.35/0.0/000/00         21 S   VEC1 22 S   RMY 21
5/6   75/46/61/+6/0.02/0.0/343/40         20 SW  VEC1 18 SW  RMY 20
5/7   78/55/67/+12/0.00/0.0/851/99        23 NW  VEC1 24 NE  RMY 23
5/8   62/49/56/+1/0.60/0.0/078/09         30 S   VEC1 31 S   RMY 31 TSTM
5/9   63/45/54/-2/0.00/0.0/588/68         33 NW  VEC1 33 NW  RMY 34
5/10  56/42/49/-7/0.00/0.0/572/66         28 ENE VEC1 27 ENE RMY 27
5/11  55/39/47/-9/0.00/0.0/617/71         26 ENE VEC1 26 NE  RMY 27
5/12  60/41/51/-6/T/0.0/305/35            16 WSW VEC1 15 SW  RMY 15
5/13  68/45/57/0/0.00/0.0/663/76          25 S   VEC1 25 SE  RMY 26
5/14  76/48/62/+5/T/0.0/718/82            33 SSW VEC1 33 SSW RMY 32
5/15  73/53/63/+6/0.46/0.0/079/09         24 ENE VEC1 24 E   RMY 24
5/16  56/52/54/-4/1.02/0.0/141/16         32 ENE VEC1 32 ENE RMY 31
5/17  66/50/58/0/0.00/0.0/662/75          29 ENE VEC1 28 ENE RMY 27
5/18  58/50/54/0/0.26/0.0/000/00          32 NE  VEC1 33 NE  RMY 34
5/19  53/48/51/-7/0.22/0.0/000/00         30 NE  VEC1 30 NE  RMY 30

5/20 The low since midnight is 48F, the daily normal low is 49F.

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MAY DAILY RECORDS TO DATE

NONE…

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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 1.97 INCHES IN 2023
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: Matt Douglas