Monday, May 19, 2025

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

MONDAY, MAY 19, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0419E
SUNSET:  1903E

PARTLY TO MOSTLY CLOUDY SKIES, GUSTY WINDS AND COOLER
TEMPERATURES MOVE INTO THE AREA TODAY….

The system that moved through yesterday afternoon brought us a
trace of precipitation, putting us at +1.19 inches for the month
and -3.47 inches for the season. The system has stalled to our
southeast and for much of today we have had increasing clouds and
cooler than normal temperatures. A strong northwesterly flow has
been present since late last night.

The temperature dipped just below 50F right before sunrise. The
temperatures rebounded slowly into the low 60s for much of the morning
and early afternoon. Increasing clouds and the persistent northwesterly
flow kept temperatures from getting to our normal range for this time
of year.

Winds have been predominantly out of the northwest today, with the
morning receiving gusts in the 30-35mph range at times. By the late
morning and early afternoon the gusts had decreased in frequency,
but it was still quite breezy overall. The average speed for the day
so far is around 17mph. The peak gust so far for today is 42mph,
which occurred at 4:O9am.

Another day of high pollen counts in our area has impacted visibility
to about 40 miles for much of the day. There was a slight improvement
to our west by the early afternoon.

The maximum temperature for today is 63F degrees, which is 5 degrees
below the normal high of 68F. The minimum temperature since midnight
is 49F degrees, which is equal to the normal low.

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Today’s Observations:

7 A.M.
Weather: Scattered altocumulus, few stratocumulus all quadrants
Temperature: 53F; Dew Point: 42F; Relative Humidity: 64%
Wind: NW @ 14G20 kts, peak wind NW 36 mph at 6:03 A.M.
Sea-level pressure: 1003.7 mb; 29.64 in. Hg: rising, then more slowly
Visibility: 40 miles
6-hr Max temp: 54F
6-hr Min temp: 49F
24-hr Precip:  Trace
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 150 SCT 40 037/53/42/3214G20/964/ FEW SC S-SW-WNW
PK WND 3131/03/ 8/550 51019 70000 10054 20049

10 A.M.
Weather: Scattered stratocumulus, scattered altocumulus
Temperature: 60F; Dew Point: 44F; Relative Humidity: 54%
Wind: NW @ 11G22 kts, peak wind NW 37 mph at 9:33 A.M.
Sea-level pressure: 1004.4 mb; 29.66 in. Hg: rising, then more slowly
Visibility: 40 miles
3-hr Precip:  0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 60 SCT 180 SCT 40 044/60/44/3211G22/966/ PK WND 3231/33/
8/550 51007

1 P.M.
Weather: Overcast stratocumulus, few breaks in overcast all quadrants
Temperature: 62F Dew Point: 45F; Relative Humidity: 54%
Wind: NW @ 10 kts
Sea-level pressure: 1004.2 mb; 29.65 in. Hg: rising, then falling
Visibility: 45 miles
6-hr Max temp: 63F
6-hr Min temp: 53F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 E85 OVC 45 042/62/45/3210/965/ 8/05/ 58002 10063 20053

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SUMMARY FOR SUNDAY, MAY 18, 2025

TEMPERATURE (DEGREES F)
MAX…….68   NORMAL…..67
MIN…….54   NORMAL…..49
MEAN……61   NORMAL…..58

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………+3
TOTAL DEPARTURE FOR THE MONTH………………………+84 [+4.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………..4  DEPARTURE……..-4
TOTAL HEATING UNITS FOR THE MONTH…………….92  DEPARTURE…….-83
TOTAL HEATING UNITS FOR THE SEASON………….5490  DEPARTURE……-572
TOTAL HEATING UNITS LAST SEASON TO DATE……..5343  DEPARTURE……+147

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH…………….11  DEPARTURE……..+2
TOTAL COOLING UNITS FOR THE SEASON……………14  DEPARTURE……..+2
TOTAL COOLING UNITS LAST SEASON TO DATE………..2  DEPARTURE…….+12

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

F420C (Official)………..39 W    @   04:02 P.M.
VECTOR #1 (1-Sec)……….39 W    @   04:02 P.M.
VECTOR #2 (1-Sec)……….40 W    @   03:59 P.M.
DAVIS #1……………….39 W    @   01:41 P.M.
DAVIS #2 ………………41 W    @   03:59 P.M.
RMY #1 (Instantaneous)…..38 W    @   03:59 P.M.
RMY #2 (Instantaneous)…..43 W    @   04:00 P.M.
MERLIN…………………39 W
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………29 W    @   04:01 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..26      @   04:01 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..29      @   04:00 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………28 W    @   04:01 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………30 W    @   04:00 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..25 WNW  @   12:05 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..28 W    @   04:00 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..15.3 W   [366 total miles] VECTOR #1………………14.7
VECTOR #2………………15.2
DAVIS #1……………….15.4 W
DAVIS #2……………….15.2 WNW
RMY #1…………………13.9 W
RMY #2…………………14.8 W
RICHARDS (C5C)…………..OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….TRACE DEPARTURE…..-0.12
TOTAL PRECIPITATION FOR THE MONTH…………..3.34 DEPARTURE…..+1.19
TOTAL PRECIPITATION FOR THE YEAR (2025)…….17.46 DEPARTURE…..-3.47

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 (2024-2025)……35.8 DEPARTURE…..-33.9

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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

5/1   69/43/56/+3/0.00/0.0/744/88        28 S   VEC1 28 SSW RMY 28
5/2   79/47/63/+9/0.19/0.0/339/40        28 SE  VEC1 29 SE  RMY 25 TSTM
5/3   84/54/69/+15/0.15/0.0/561/66       43 SSW VEC1 42 SSW RMY 44 TSTM
5/4   77/50/64/+10/0.06/0.0/256/30       33 SW  VEC1 34 SW  RMY 32
5/5   50/46/48/-7/0.26/0.0/000/00        35 ENE VEC1 35 ENE RMY 36
5/6   61/48/55/0/0.57/0.0/000/00         26 S   VEC1 27 ENE RMY 27
5/7   72/54/63/+8/0.01/0.0/310/36        33 SSW VEC1 33 SW  RMY 35
5/8   74/51/63/+8/0.04/0.0/474/55        18 ESE VEC1 18 ESE RMY 18
5/9   51/46/49/-7/1.15/0.0/000/00        33 E   VEC1 34 ENE RMY 35
5/10  62/45/54/-2/0.29/0.0/121/14        36 NW  VEC1 37 NW  RMY 41
5/11  70/49/60/+4/0.00/0.0/851/98        33 NW  VEC1 32 NW  RMY 34
5/12  73/46/60/+3/0.00/0.0/853/98        36 SW  VEC1 34 SW  RMY 36
5/13  70/51/61/+4/0.00/0.0/759/87        26 ESE VEC1 27 ESE RMY 26
5/14  73/48/61/+4/0.00/0.0/586/67        18 SSE VEC1 19 SSE RMY 17
5/15  72/58/65/+8/0.62/0.0/079/09        20 SSE VEC1 20 SSE RMY 19 TSTM
5/16  78/61/70/+12/0.00/0.0/404/46       23 SW  VEC1 23 SSW RMY 23
5/17  76/58/67/+9/T/0.0/…/..           30 S   VEC1 29 S   RMY 30
5/18  68/54/61/+3/T/0.0/…/..           39 W   VEC1 39 W   RMY 38

5/19 The low since midnight is 49F, the daily normal low is 49F.

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MAY DAILY RECORDS TO DATE

5/16 RECORD HIGH MINIMUM TEMPERATURE OF 61F;
PREVIOUS RECORD WAS 60F SET IN 2014

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

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

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

TODAY’S REPORT PREPARED BY: Amanda Joly