Thursday, May 15, 2025

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

THURSDAY, MAY 15, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0422E
SUNSET:  1859E

MORNING SHOWERS AND THUNDERSTORMS GIVE WAY TO MAINLY CLOUDY, BUT
MUGGY AFTERNOON….

An area of showers and thunderstorms moved through the area this
morning, bringing a total of 0.62″ of much needed rain to Blue
Hill. These showers finally moved out during the late morning
hours leaving us with mainly cloudy skies into early this afternoon.
A few splashes of sun have been observed at times as well.

Temperatures have warmed into the lower 70s by early this afternoon,
however it’s the dew point rise that’s been the most noticeable. Dew
point values have risen into the mid 60s by early this afternoon,
which are the highest values we’ve seen so far this season. Needless
to say it feels rather muggy out there this afternoon.

Winds were steady for the first half of the morning, but have been
decreasing into early this afternoon. The average speed for the day
so far is around 9mph, mainly out of the southeast and south-
southeast. The peak gust for the day occurred at 8am this morning
with a value of 20mph.

Visibility has been gradually improving, from around 1/16th of a
mile early this morning to around 15-20 miles early this afternoon.

The maximum temperature for today is 72F degrees, which is 5 degrees
above the normal high of 67F. The minimum temperature since midnight
is 58F degrees, which is 10 degrees above the normal low of 48F.

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Today’s Observations:

7 A.M.
Weather: Sky obscured, vertical visibility 200ft, light rain showers
Temperature: 59F; Dew Point: 59F; Relative Humidity: 100%
Wind: SE @ 8 kts
Sea-level pressure: 1016.1 mb; 30.01 in. Hg: falling, then more rapidly
Visibility: 1/8th mile, fog
6-hr Max temp: 59F
6-hr Min temp: 58F
24-hr Precip:  0.46 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 X W2 1/8RW-F 161/59/59/1408/001/ TB40E55 OCNL LTGIC/
8//// 58011 6046/ 70046 10059 20058

10 A.M.
Weather: Broken stratus fractus, broken stratocumulus, broken nimbostratus,
broken altocumulus, few lower stratus fractus all quadrants, very light
rain showers
Temperature: 66F; Dew Point: 66F; Relative Humidity: 99%
Wind: SSE @ 6 kts, wind light
Sea-level pressure: 1015.1 mb; 29.98 in. Hg: falling, then more rapidly
Visibility: 4 miles, 10 miles NE and S-SSW, fog
3-hr Precip:  0.16 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 E1 BKN 40 BKN 65 BKN 85 BKN 4RW-F 151/66/66/1506/998/
FEW LWR STFRA ALQDS RW-E08B29 PCPN VRY LGT VSBY 10 NE AND S-SSW
WND LGT/ 8/770 58010 6016/

1 P.M.
Weather: Overcast stratocumulus, few lower stratus fractus distant
W-N-NE
Temperature: 71F Dew Point: 66F; Relative Humidity: 85%
Wind: S @ 5 kts, wind light
Sea-level pressure: 1013.9 mb; 29.94 in. Hg: falling, then more rapidly
Visibility: 20 miles, 15 miles WNW-NW and N-ENE, thin fog
6-hr Max temp: 72F
6-hr Min temp: 59F
6-hr Precip:  0.16 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 E20 OVC 20 139/71/66/1805/994/ FEW LWR STFRA DSNT W-N-NE
THN F ALQDS VSBY 15 WNW-NW AND N-ENE WND LGT/ 8/5// 58012 6016/
10072 20059

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SUMMARY FOR WEDNESDAY, MAY 14, 2025

TEMPERATURE (DEGREES F)
MAX…….73   NORMAL…..66
MIN…….48   NORMAL…..48
MEAN……61   NORMAL…..57

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+4
TOTAL DEPARTURE FOR THE MONTH………………………+52 [+3.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………..4  DEPARTURE……..-5
TOTAL HEATING UNITS FOR THE MONTH…………….88  DEPARTURE…….-55
TOTAL HEATING UNITS FOR THE SEASON………….5486  DEPARTURE……-544
TOTAL HEATING UNITS LAST SEASON TO DATE……..5312  DEPARTURE……+174

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH……………..4  DEPARTURE……..-3
TOTAL COOLING UNITS FOR THE SEASON…………….7  DEPARTURE……..-3
TOTAL COOLING UNITS LAST SEASON TO DATE………..2  DEPARTURE……..+5

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)………..18 SSE  @   12:21 A.M.
VECTOR #1 (1-Sec)……….19 SSE  @   12:20 A.M.
VECTOR #2 (1-Sec)……….17 SE   @   12:30 A.M.
DAVIS #1……………….18 SSE  @   12:27 A.M.
DAVIS #2 ………………17 SE   @   12:26 A.M.
RMY #1 (Instantaneous)…..17 SSE  @   12:20 A.M.
RMY #2 (Instantaneous)…..18 NE   @   02:23 P.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………14 SSE  @   12:34 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..14      @   12:19 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..14      @   12:28 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………14 SSE  @   12:05 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………14 SE   @   12:28 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..13 SSE  @   12:04 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 SSE  @   12:08 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………6.3 SE [151 total miles] VECTOR #1……………….6.9
VECTOR #2……………….7.3
DAVIS #1………………..6.8 ESE
DAVIS #2………………..6.8 ESE
RMY #1………………….6.7 ESE
RMY #2………………….7.4 ESE
RICHARDS (C5C)…………..OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.46 DEPARTURE…..+0.35
TOTAL PRECIPITATION FOR THE MONTH…………..3.18 DEPARTURE…..+1.50
TOTAL PRECIPITATION FOR THE YEAR (2025)…….17.30 DEPARTURE…..-3.16

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 The low since midnight is 58F, the daily normal low is 48F.

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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 15
HIGH 93F IN 1900
LOW 36F IN 1947,1985
PRECIP 1.63 INCHES IN 1978
PEAK GUST 53e MPH NE IN 1978, W 2002

RECORDS FOR MAY 16
HIGH 90F IN 1951
LOW 30F IN 1936
PRECIP 2.63 INCHES IN 1954
PEAK GUST 56e MPH NW IN 1952

TODAY’S REPORT PREPARED BY: MFD