Saturday, May 20, 2023

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

SATURDAY, MAY 20, 2023
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0418E
SUNSET:  1904E

RAINY WITH LOW VISIBILITY AS WE HEAD INTO THE AFTERNOON
HOURS….

Today started off with a limited visibility of 15 miles due to haze,
and got worse from there! This morning included spot showers leaving
trace amounts of rainfall, and rain became stronger and more
consistent around noontime. Since then, we have been experiencing
a visibility around a 1/2 mile with a rainfall rate around 0.15 inches
per hour.

Rainfall is definitely needed however, as both the monthly and
annual rain deficits are around 2 inches. This will hopefully make
up for our less than satisfactory April showers!

Our high temperature so far today is 65F, 3 degrees below the
normal of 68F. The low since midnight is 51F, which is 2 degrees
above the normal low of 49F.

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Today’s Observations:

7 A.M.
Weather: Broken stratocumulus, overcast altostratus
Temperature: 60F; Dew Point: 55F; Relative Humidity: 83%
Wind: S @ 8 kts
Sea-level pressure: 1023.6 mb; 30.23 in. Hg: rising then falling
Visibility: 15 miles, hazy
6-hr Max temp: 60F
6-hr Min temp: 51F
24-hr Precip:  0.00 ins.
BHO SA 1155 50 BKN 100 OVC 15 236/60/55/1808/023/ HAZY/ 8/52/
50001 10060 20051

10 A.M.
Weather: Broken cumulus fractus, overcast nimbostratus,
rain shower for around 10 minutes before the top of the hour
Temperature: 64F; Dew Point: 58F; Relative Humidity: 80%
Wind: SSE @ 8G15 kts,
Sea-level pressure: 1022.9 mb; 30.21 in. Hg: falling, then more
slowly
Visibility: 10 miles, hazy
3-hr Precip:  Trace
BHO SA 1455 50 BKN 100 OVC 10 229/64/58/1608G15/021/ HAZY RW-B45E55/
8/72/ 56007 6000/

1 P.M.
Weather: Rain and fog
Temperature: 62F; Dew Point: 62F; Relative Humidity: 100%
Wind: SE @ 7 kts
Sea-level pressure: 1020.0 mb; 30.11 in. Hg: falling, then less
rapidly
Visibility: 1/2 mile
6-hr Max temp: 65F
6-hr Min temp: 60F
6-hr Precip:  0.22 ins.
BHO SA 1755 X W3 1/2RF 200/62/62/1307/011/ 8//// 56029
6022/ 10065 20060

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SUMMARY FOR FRIDAY, MAY 19, 2023

TEMPERATURE (DEGREES F)
MAX…….68   NORMAL…..68
MIN…….42   NORMAL…..49
MEAN……55   NORMAL…..58

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL………-3
TOTAL DEPARTURE FOR THE MONTH………………..+31 [+1.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2022 THRU JUN 2023)
TOTAL HEATING UNITS FOR YESTERDAY……………10  DEPARTURE……..+2
TOTAL HEATING UNITS FOR THE MONTH…………..147  DEPARTURE…….-36
TOTAL HEATING UNITS FOR THE SEASON…………5118  DEPARTURE……-952
TOTAL HEATING UNITS LAST SEASON TO DATE…….5542  DEPARTURE……-424

COOLING DEGREE DAYS (SEASON: JAN 2023 THRU DEC 2023)
TOTAL COOLING UNITS FOR YESTERDAY…………….0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH……………16  DEPARTURE……..+6
TOTAL COOLING UNITS FOR THE SEASON…………..25  DEPARTURE…….+12
TOTAL COOLING UNITS LAST SEASON TO DATE………24  DEPARTURE……..+1

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)………..36 SSW @   5:05 P.M.
VECTOR #1 (1-Sec)……….39 SSW @   7:02 P.M.
VECTOR #2 (1-Sec)……….40 SSW @   5:06 P.M.
DAVIS #1……………….41 S   @   3:48 P.M.
DAVIS #2 ………………42 S   @   5:06 P.M.
RMY #1 (Instantaneous)…..40 SSW @   5:06 P.M.
RMY #2 (Instantaneous)…..40 SSW @   5:06 P.M.
MERLIN…………………34 SW
RICHARDS (C5C) (Inst)……35     @   6:37 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………26 SSW @   6:08 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..26     @   5:05 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..28     @   5:06 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………26 S   @   6:08 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………30 S   @   5:06 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..26 SSW @   6:08 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..28 SSW @   5:06 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………25     @   6:04 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………15.9 SSW [382 total miles] VECTOR #1……………….15.7
VECTOR #2……………….16.6
DAVIS #1………………..15.2 SSW
DAVIS #2………………..16.8 SSW
RMY #1………………….15.5 SSW
RMY #2………………….16.6 SSW
RICHARDS (C5C)…………..14.8

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.11
TOTAL PRECIPITATION FOR THE MONTH…………..0.45 DEPARTURE…..-1.80
TOTAL PRECIPITATION FOR THE YEAR…………..18.65 DEPARTURE…..-2.38

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 (2022-2023)……34.9 DEPARTURE…..-34.8

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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

5/1   63/45/54/+1/0.04/0.0/540/64         44 SSE  VEC1 46 SSE RMY 48
5/2   57/43/50/-4/0.22/0.0/144/17         33 S    VEC1 34 S   RMY 35
5/3   55/42/49/-5/0.01/0.0/093/11         25 E    VEC1 25 E   RMY 25
5/4   45/40/43/-11/0.07/0.0/009/01        29 NE   VEC1 29 NE  RMY 29
5/5   59/43/51/-4/0.07/0.0/367/43         18 NE   VEC1 19 NE  RMY 19
5/6   74/43/59/+4/0.00/0.0/847/99         25 NW   VEC1 26 NW  RMY 26
5/7   78/52/65/+10/0.01/0.0/789/92        26 WNW  VEC1 27 W   RMY 28
5/8   74/49/62/+7/0.03/0.0/800/93         32 NW   VEC1 33 NW  RMY 35
5/9   60/45/53/-3/0.00/0.0/819/95         24 NE   VEC1 25 NE  RMY 25
5/10  72/51/62/+6/0.00/0.0/830/96         25 WSW  VEC1 26 WSW RMY 26
5/11  81/53/67/+11/T/0.0/729/84           30 W    VEC1 30 W   RMY 30
5/12  84/57/71/+14/T/0.0/687/79           31 WNW  VEC1 35 WNW RMY 34
5/13  81/58/70/+13/0/0.0/715/82           28 NNW  VEC1 30 NNW RMY 35
5/14  66/47/57/0/0.00/0.0/822/94          28 NNW  VEC1 29 NNW RMY 31
5/15  72/45/59/+2/0.00/0.0/675/77         33 W    VEC1 35 W   RMY 34
5/16  80/55/68/+10/0.00/0.0/…/..        38 SW   VEC1 39 SW  RMY 41
5/17  62/37/50/-8/0.00/0.0/…/..         36 NNW  VEC1 37 NNW RMY 40
5/18  64/34/49/-9/0.00/0.0/…/..         26 SSW  VEC1 28 SSW RMY 28
5/19  68/42/55/-3/0.00/0.0/…/..         36 SSW  VEC1 36 SSW RMY 34

5/20 The low since midnight is 51F, the daily normal low is 49F

DAILY RECORDS

05/18/2023: NEW RECORD LOW MINIMUM TEMPERATURE OF 34F,
THIS BEATS THE OLD RECORD OF 35F SET IN 2002

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: Benjamin Turner