Station 44020 (LLNR 13700) - NANTUCKET SOUND Image indicating link to RSS feed of recent meteorological observations for station 44020


Conditions at 44020 as of
(1:10 am EST)
0610 GMT on 11/21/2024:
     

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

5-day plot - Wind Direction Wind Direction (WDIR): NE ( 40 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 7.8 kts
5-day plot - Wind Gust Wind Gust (GST): 9.7 kts
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES):29.71 in
5-day plot - Air Temperature Air Temperature (ATMP): 48.6 °F
5-day plot - Water Temperature Water Temperature (WTMP): 51.4 °F
5-day plot - Dew Point Dew Point (DEWP): 46.9 °F
5-day plot - Wind Chill Wind Chill (CHILL): 44.6 °F
5-day plot - Wind Speed at 10 Meters Wind Speed at 10 meters (WSPD10M): 7.8 kts
5-day plot - Wind Speed at 20 Meters Wind Speed at 20 meters (WSPD20M): 7.8 kts
5-day plot -  Wind Speed, Wind Gust and Atmospheric Pressure Combined plot of Wind Speed, Gust, and Air Pressure
Supplemental Measurements
Highest 1-minute Wind Speed
Time (EST)5-day plot - 1-Minute Wind Speed WSPD 5-day plot - 1-Minute Wind Direction WDIR
1:05 am 7.8 kts-
Previous observations
TIME
(EST)
5-day plot - Wind Direction
WDIR
 
5-day plot - Wind Speed
WSPD
kts
5-day plot - Wind Gust
GST
kts
5-day plot - Wave Height
WVHT
ft
5-day plot - Dominant Wave Period
DPD
sec
5-day plot - Average Wave Period
APD
sec
5-day plot - Mean Wave Direction
MWD
 
5-day plot - Atmospheric Pressure
PRES
in
5-day plot - Pressure Tendency
PTDY
in
5-day plot - Air Temperature
ATMP
°F
5-day plot - Water Temperature
WTMP
°F
5-day plot - Dew Point
DEWP
°F
5-day plot - Salinity
SAL
psu
5-day plot - Visibility
VIS
nmi
5-day plot - Tide (above MLLW)
TIDE
ft
2024-11-21 01:00 am NE 9.7 11.7----29.72-0.05 48.7 51.4 46.9---
2024-11-21 12:50 am NE 9.7 11.7 1.0 33.0ENE29.72- 48.9 51.4 46.9---
2024-11-21 12:40 amENE 9.7 11.7----29.73- 48.7 51.4 46.6---
2024-11-21 12:30 am NE 7.8 11.7----29.73- 48.6 51.4 46.6---
2024-11-21 12:20 am NE 7.8 9.7 1.0 33.1 E29.73- 48.4 51.4 46.2---
2024-11-21 12:10 am NE 7.8 11.7 1.0-3.1 E29.74- 48.6 51.4 46.2---
2024-11-21 12:00 am NE 9.7 11.7----29.74-0.04 48.7 51.4 46.0---
2024-11-20 11:50 pmENE 9.7 13.6 1.0 33.0 E29.73- 48.9 51.3 45.9---
2024-11-20 11:40 pm NE 11.7 13.6----29.74- 48.9 51.3 45.7---
2024-11-20 11:30 pm NE 11.7 13.6----29.74- 48.9 51.1 45.5---
2024-11-20 11:20 pm NE 11.7 13.6 1.0 33.1ENE29.75- 48.7 51.1 45.3---
2024-11-20 11:10 pm NE 11.7 15.5 1.0-3.1ENE29.75- 48.7 50.9 45.3---
2024-11-20 11:00 pmENE 9.7 13.6----29.76-0.03 48.9 51.1 45.7---
2024-11-20 10:50 pm NE 9.7 11.7 1.0 33.1ENE29.76- 48.7 51.1 45.3---
2024-11-20 10:40 pmENE 9.7 13.6----29.76- 48.6 51.1 45.1---
2024-11-20 10:30 pmENE 9.7 13.6----29.76- 48.6 50.9 45.0---
2024-11-20 10:20 pmENE 9.7 11.7 1.0 33.1ENE29.77- 48.6 50.9 45.1---
2024-11-20 10:10 pmENE 9.7 13.6 1.0-3.1ENE29.77- 48.4 50.9 44.8---
2024-11-20 10:00 pmENE 9.7 13.6----29.77-0.01 48.2 50.7 44.8---
2024-11-20 09:50 pm NE 9.7 13.6 1.0 33.1ENE29.77- 48.4 50.7 45.1---
2024-11-20 09:40 pm NE 7.8 11.7----29.77- 48.4 50.7 45.1---
2024-11-20 09:30 pm NE 9.7 13.6----29.77- 48.2 50.7 45.1---
2024-11-20 09:20 pm NE 9.7 11.7 1.0 33.0ENE29.77- 48.4 50.7 45.5---
2024-11-20 09:10 pmNNE 9.7 11.7 1.0-3.0ENE29.77- 48.4 50.7 45.3---
2024-11-20 09:00 pmNNE 7.8 11.7----29.77+0.00 48.4 50.7 45.1---
2024-11-20 08:50 pm NE 9.7 11.7 1.0 33.1 E29.78- 48.2 50.7 45.0---
2024-11-20 08:40 pm NE 9.7 11.7----29.78- 48.4 50.7 45.1---
2024-11-20 08:30 pmENE 7.8 9.7----29.79- 48.6 50.7 45.3---
2024-11-20 08:20 pm NE 7.8 9.7 1.0 32.9ENE29.79- 48.7 50.7 45.3---
2024-11-20 08:10 pmNNE 5.8 9.7 1.0-2.9ENE29.79- 48.6 50.7 45.0---
2024-11-20 08:00 pmNNE 7.8 11.7----29.79+0.00 48.4 50.7 44.8---
2024-11-20 07:50 pm NE 7.8 11.7 1.0 22.9 NE29.79- 48.4 50.7 45.0---
2024-11-20 07:40 pm NE 7.8 11.7----29.78- 48.4 50.7 45.0---
2024-11-20 07:30 pm NE 9.7 13.6----29.78- 48.6 50.9 45.1---
2024-11-20 07:20 pm NE 9.7 13.6 1.0 22.7 NE29.78- 48.4 50.9 45.0---
2024-11-20 07:10 pm NE 11.7 13.6 1.0-2.7 NE29.78- 48.4 50.9 44.8---
2024-11-20 07:00 pm NE 11.7 17.5----29.78+0.00 48.2 51.1 44.8---
2024-11-20 06:50 pmNNE 11.7 15.5 1.0 22.7 NE29.78- 48.4 51.1 45.0---
2024-11-20 06:40 pmNNE 11.7 15.5----29.78- 48.2 51.1 44.8---
2024-11-20 06:20 pmNNE 11.7 19.4 1.0 22.7 NE29.77- 48.0 51.1 44.6---
2024-11-20 06:10 pmNNE 11.7 15.5----29.78- 47.8 51.1 44.4---
2024-11-20 06:00 pm NE 11.7 17.5----29.78+0.01 47.7 51.1 44.2---
2024-11-20 05:50 pm NE 11.7 15.5 1.0 22.7NNE29.78- 47.7 51.3 44.1---
2024-11-20 05:40 pmNNE 13.6 17.5----29.78- 47.7 51.3 44.2---
2024-11-20 05:30 pm N 11.7 15.5----29.78- 47.5 51.4 43.9---
2024-11-20 05:20 pm N 11.7 15.5 1.0 22.6NNE29.78- 47.5 51.4 43.7---
2024-11-20 05:10 pmNNE 11.7 15.5 1.0-2.6NNE29.79- 47.5 51.4 43.7---
2024-11-20 05:00 pmNNE 13.6 15.5----29.79+0.03 47.7 51.4 44.1---
2024-11-20 04:50 pm N 11.7 15.5 1.0 22.6 NE29.78- 47.8 51.4 44.1---
2024-11-20 04:40 pmNNE 11.7 13.6----29.79- 48.0 51.4 44.2---
2024-11-20 04:30 pmNNE 9.7 13.6----29.79- 48.0 51.4 44.1---
2024-11-20 04:20 pmNNE 9.7 13.6 1.0 22.7 NE29.79- 48.0 51.4 44.1---
2024-11-20 04:10 pmNNE 11.7 15.5 1.0-2.7 NE29.78- 48.0 51.4 43.9---
2024-11-20 04:00 pmNNE 9.7 13.6----29.78+0.03 48.2 51.4 44.1---
2024-11-20 03:50 pm N 11.7 15.5 1.3 22.7NNE29.78- 48.6 51.4 44.6---
2024-11-20 03:40 pm N 9.7 13.6----29.78- 48.6 51.4 44.4---
2024-11-20 03:30 pmNNE 11.7 15.5----29.78- 48.7 51.4 44.4---
2024-11-20 03:20 pm N 11.7 15.5 1.0 22.9NNE29.77- 48.6 51.4 44.2---
2024-11-20 03:10 pm N 13.6 15.5 1.0-2.9NNE29.77- 48.7 51.4 44.4---
2024-11-20 03:00 pm N 11.7 15.5----29.76+0.01 48.7 51.4 44.2---
2024-11-20 02:50 pm N 9.7 13.6 1.0 63.0 E29.76- 48.7 51.4 44.1---
2024-11-20 02:40 pm N 11.7 13.6----29.76- 48.9 51.4 44.2---
2024-11-20 02:30 pm N 9.7 13.6----29.76- 48.9 51.4 44.2---
2024-11-20 02:20 pmNNE 9.7 13.6 1.0 22.9NNE29.76- 49.1- 44.4---
2024-11-20 02:10 pm N 11.7 13.6 1.0-2.9NNE29.76- 49.3 51.4 44.6---
2024-11-20 02:00 pm N 9.7 11.7----29.76-0.01 49.3 51.4 44.4---
2024-11-20 01:50 pm N 7.8 9.7 1.0 32.9 N29.76- 49.3 51.4 44.4---
2024-11-20 01:40 pm N 7.8 9.7----29.76- 49.1 51.4 44.1---
2024-11-20 01:30 pm N 9.7 13.6----29.76- 49.3 51.4 44.4---
2024-11-20 01:20 pm N 9.7 13.6 1.0 22.8 N29.76- 49.5 51.4 44.6---
2024-11-20 01:10 pm N 9.7 13.6 1.0-2.8 N29.76- 49.3 51.4 44.2---
2024-11-20 01:00 pm N 7.8 13.6----29.76-0.04 49.3 51.4 44.1---
2024-11-20 12:50 pm N 9.7 13.6 1.0 32.7 N29.76- 49.3 51.4 44.2---
2024-11-20 12:40 pm N 9.7 15.5----29.75- 49.5 51.4 44.4---
2024-11-20 12:30 pm N 11.7 13.6----29.75- 49.5- 44.4---
2024-11-20 12:20 pm N 11.7 13.6 1.0 32.8NNE29.75- 49.6 51.6 44.6---
2024-11-20 12:10 pm N 11.7 15.5 1.0-2.8NNE29.75- 49.8 51.6 44.8---
2024-11-20 12:00 pm N 11.7 15.5----29.75-0.04 49.8 51.6 44.6---
2024-11-20 11:50 am N 11.7 15.5 1.0 32.7 N29.75- 50.0 51.6 44.8---
2024-11-20 11:40 am N 11.7 13.6----29.75- 50.0 51.6 44.8---
2024-11-20 11:30 am N 11.7 13.6----29.76- 50.2 51.6 45.1---
2024-11-20 11:20 am N 11.7 13.6 0.7-2.7-29.77- 50.2 51.6 45.1---
2024-11-20 11:10 am N 11.7 13.6 0.7-2.7-29.77- 50.2 51.6 45.3---
2024-11-20 11:00 am N 11.7 13.6----29.77-0.02 50.2 51.6 45.1---
2024-11-20 10:50 am N 9.7 13.6 0.7-2.7-29.78- 50.4 51.6 45.3---
2024-11-20 10:40 am N 9.7 11.7----29.78- 50.2 51.6 45.0---
2024-11-20 10:30 am N 9.7 13.6----29.79- 50.2 51.4 45.1---
2024-11-20 10:20 am N 11.7 13.6 0.7-2.9-29.79- 50.2- 45.3---
2024-11-20 10:10 am N 9.7 13.6 0.7-2.9-29.79- 50.0 51.4 45.3---
2024-11-20 10:00 amNNW 9.7 11.7----29.80+0.01 49.5 51.4 45.1---
2024-11-20 09:50 amNNW 9.7 9.7 0.7-2.6-29.80- 48.9 51.3 44.6---
2024-11-20 09:40 amNNW 9.7 11.7----29.80- 48.6 51.3 44.2---
2024-11-20 09:30 amNNW 9.7 11.7----29.80- 48.4 51.3 44.2---
2024-11-20 09:20 amNNW 9.7 11.7 0.7-2.7-29.80- 48.2 51.3 44.1---
2024-11-20 09:10 amNNW 9.7 11.7 0.7-2.7-29.80- 48.2 51.3 44.2---
2024-11-20 09:00 amNNW 9.7 11.7----29.80+0.02 48.0 51.3 44.2---
2024-11-20 08:50 amNNW 9.7 11.7 0.7-2.9-29.79- 47.8 51.3 44.1---
2024-11-20 08:40 am NW 9.7 11.7----29.80- 47.8 51.3 43.9---
2024-11-20 08:30 amNNW 9.7 11.7----29.79- 47.7 51.3 43.7---
2024-11-20 08:20 amNNW 9.7 11.7 0.7-2.9-29.79- 47.7 51.3 43.7---
2024-11-20 08:10 amNNW 9.7 11.7 0.7-2.9-29.79- 47.5 51.3 43.5---
2024-11-20 08:00 amNNW 9.7 11.7----29.79+0.01 47.3 51.3 43.3---
2024-11-20 07:50 amNNW 9.7 11.7 0.7-2.8-29.79- 46.9 51.3 43.0---
2024-11-20 07:40 amNNW 7.8 9.7----29.79- 46.4 51.3 42.4---
2024-11-20 07:30 amNNW 7.8 9.7----29.79- 46.4 51.3 42.4---
2024-11-20 07:20 amNNW 7.8 9.7 0.7-2.9-29.79- 46.2 51.3 42.3---
2024-11-20 07:10 amNNW 7.8 9.7 0.7-2.9-29.79- 46.0 51.3 42.1---
2024-11-20 07:00 amNNW 7.8 9.7----29.79+0.03 45.9 51.3 41.9---
2024-11-20 06:50 amNNW 7.8 9.7 0.7-2.8-29.79- 45.5 51.3 41.7---
2024-11-20 06:40 amNNW 7.8 9.7----29.78- 45.3 51.3 41.4---
2024-11-20 06:30 amNNW 7.8 11.7----29.78- 45.1 51.3 40.6---
2024-11-20 06:20 amNNW 7.8 9.7 1.0 32.8 NW29.78- 45.1 51.3 40.6---
2024-11-20 06:10 am NW 9.7 9.7 1.0-2.8 NW29.78- 45.3 51.4 40.6---
2024-11-20 06:00 am NW 9.7 9.7----29.78+0.02 45.5 51.4 40.8---
2024-11-20 05:50 amNNW 9.7 11.7 1.0 32.8WNW29.78- 45.7 51.4 40.8---
2024-11-20 05:40 amNNW 9.7 9.7----29.78- 46.0 51.4 41.4---
2024-11-20 05:30 am NW 9.7 9.7----29.78- 46.2 51.4 41.5---
2024-11-20 05:20 am NW 9.7 11.7 1.0 32.8WNW29.78- 46.4 51.4 41.7---
2024-11-20 05:10 am NW 9.7 11.7 1.0-2.8WNW29.78- 46.6 51.4 41.7---
2024-11-20 05:00 amNNW 9.7 11.7----29.78+0.02 46.8 51.4 42.1---
2024-11-20 04:50 amNNW 9.7 11.7 1.0 32.8WNW29.78- 46.4 51.4 41.5---
2024-11-20 04:40 amNNW 11.7 13.6 1.0-2.8WNW29.78- 46.6 51.4 41.9---
2024-11-20 04:30 amNNW 11.7 13.6----29.78- 46.4 51.4 41.4---
2024-11-20 04:20 amNNW 11.7 15.5 1.0 32.9WNW29.77- 46.4 51.4 41.5---
2024-11-20 04:10 amNNW 13.6 13.6 1.0-2.9WNW29.76- 46.2 51.4 41.5---
2024-11-20 04:00 amNNW 11.7 13.6----29.76+0.00 46.2 51.4 41.4---
2024-11-20 03:50 amNNW 11.7 13.6 1.0 33.0WNW29.75- 46.2 51.4 41.2---
2024-11-20 03:40 amNNW 11.7 13.6----29.76- 46.2 51.4 41.2---
2024-11-20 03:30 am NW 11.7 13.6----29.76- 46.2 51.4 41.2---
2024-11-20 03:20 am NW 11.7 13.6 1.0 32.9 NW29.76- 46.2 51.4 41.0---
2024-11-20 03:10 am NW 11.7 13.6 1.0-2.9 NW29.76- 46.6 51.4 41.5---
2024-11-20 03:00 am NW 11.7 13.6----29.76+0.00 46.6 51.4 41.4---
2024-11-20 02:50 am NW 11.7 13.6 1.0 32.9WNW29.76- 46.8 51.4 41.4---
2024-11-20 02:40 am NW 11.7 13.6----29.77- 46.9 51.4 41.7---
2024-11-20 02:30 am NW 11.7 13.6----29.77- 46.9 51.4 41.7---
2024-11-20 02:20 am NW 11.7 13.6 1.0 32.7WNW29.76- 46.9 51.4 41.7---
2024-11-20 02:10 am NW 11.7 13.6 1.0-2.7WNW29.76- 46.9 51.4 41.5---
2024-11-20 02:00 am NW 11.7 13.6----29.76+0.00 46.8 51.4 41.2---
2024-11-20 01:50 am NW 11.7 13.6 0.7-2.6-29.76- 46.8 51.4 41.0---
2024-11-20 01:40 am NW 11.7 13.6----29.76- 46.8 51.4 40.8---
2024-11-20 01:30 amWNW 11.7 13.6----29.77- 46.9 51.4 41.0---
2024-11-20 01:20 amWNW 11.7 13.6 0.7-2.8-29.77- 47.3 51.4 41.2---
2024-11-20 01:10 amWNW 11.7 13.6 0.7-2.8-29.76- 47.3 51.4 41.2---
2024-11-20 01:00 amWNW 9.7 11.7----29.76-0.01 47.5 51.4 41.2---
2024-11-20 12:50 amWNW 7.8 9.7 0.3-2.8-29.76- 47.8 51.6 41.5---

Detailed Wave Summary
for 44020 as of (12:40 am EST)
0540 GMT on 11/21/2024:

These wave data are displayed in rounded times.

     

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

5-day plot - Significant Wave Height Significant Wave Height (WVHT): 1.0 ft
5-day plot - Swell Height Swell Height (SwH): 0.3 ft
5-day plot - Swell Period Swell Period (SwP): 4.8 sec
5-day plot - Swell Direction Swell Direction (SwD):ESE
5-day plot - Wind Wave Height Wind Wave Height (WWH): 1.0 ft
5-day plot - Wind Wave Period Wind Wave Period (WWP): 3.0 sec
5-day plot - Wind Wave Direction Wind Wave Direction (WWD):ENE
5-day plot - Average Wave Period Average Wave Period (APD): 3.0 sec
Previous observations
TIME
(EST)
5-day plot - Wave Height
WVHT
ft
5-day plot - Swell Height
SwH
ft
5-day plot - Swell Period
SwP
sec
5-day plot - Swell Direction
SwD
 
5-day plot - Wind Wave Height
WWH
ft
5-day plot - Wind Wave Period
WWP
sec
5-day plot - Wind Wave Direction
WWD
 
5-day plot - Wave Steepness
STEEPNESS
 
5-day plot - Average Wave Period
APD
sec
2024-11-21 12:10 am 1.0 0.3 4.3ESE 1.0 3.0 E N/A 3.1
2024-11-20 11:40 pm 1.0 0.3 6.2ESE 1.0 2.9 E N/A 3.0
2024-11-20 11:10 pm 1.0 0.3 6.2 E 1.0 3.0 ENE N/A 3.1
2024-11-20 10:40 pm 1.0 0.3 6.7 E 0.7 2.9 ENE N/A 3.1
2024-11-20 10:10 pm 1.0 0.3 7.1ESE 1.0 2.6 ENE N/A 3.1
2024-11-20 09:40 pm 1.0 0.3 4.3 E 1.0 2.9 ENE N/A 3.1
2024-11-20 09:10 pm 1.0 0.3 6.7ESE 1.0 2.9 ENE N/A 3.0
2024-11-20 08:40 pm 1.0 0.3 6.2ESE 0.7 2.9 E N/A 3.1
2024-11-20 08:10 pm 1.0 0.7 6.7ESE 1.0 2.6 ENE N/A 2.9
2024-11-20 07:40 pm 1.0 0.7 6.7ESE 1.0 2.5 NE N/A 2.9
2024-11-20 07:10 pm 1.0 0.3 5.9ESE 1.0 2.2 NE N/A 2.7
2024-11-20 06:40 pm 1.0 0.3 6.7ESE 1.0 2.4 NE N/A 2.7
2024-11-20 06:10 pm 1.0 0.3 5.6ESE 1.0 2.5 NE N/A 2.7
2024-11-20 05:40 pm 1.0 0.3 5.3 E 1.0 2.2 NNE N/A 2.7
2024-11-20 05:10 pm 1.0 0.3 5.3 E 1.0 2.5 NNE N/A 2.6
2024-11-20 04:40 pm 1.0 0.3 5.9ESE 1.0 2.2 NE N/A 2.6
2024-11-20 04:10 pm 1.0 0.3 5.9ESE 1.0 2.5 NE N/A 2.7
2024-11-20 03:40 pm 1.3 0.3 5.6ESE 1.0 2.2 NNE N/A 2.7
2024-11-20 03:10 pm 1.0 0.3 5.9 E 1.0 2.2 NNE N/A 2.9
2024-11-20 02:40 pm 1.0 0.3 5.6 E 1.0 2.2 NNE N/A 3.0
2024-11-20 02:10 pm 1.0 0.3 5.3ESE 1.0 2.5 NNE N/A 2.9
2024-11-20 01:40 pm 1.0 0.7 5.6ESE 1.0 2.6 N N/A 2.9
2024-11-20 01:10 pm 1.0 0.3 5.6ESE 1.0 2.5 N N/A 2.8
2024-11-20 12:40 pm 1.0 0.3 6.2ESE 1.0 2.7 N N/A 2.7
2024-11-20 12:10 pm 1.0 0.3 6.7ENE 1.0 2.7 NNE N/A 2.8
2024-11-20 11:40 am 1.0 0.3 6.2ESE 1.0 2.6 N N/A 2.7
2024-11-20 11:10 am 0.7------ N/A 2.7
2024-11-20 10:40 am 0.7------ N/A 2.7
2024-11-20 10:10 am 0.7------ N/A 2.9
2024-11-20 09:40 am 0.7------ N/A 2.6
2024-11-20 09:10 am 0.7------ N/A 2.7
2024-11-20 08:40 am 0.7------ N/A 2.9
2024-11-20 08:10 am 0.7------ N/A 2.9
2024-11-20 07:40 am 0.7------ N/A 2.8
2024-11-20 07:10 am 0.7------ N/A 2.9
2024-11-20 06:40 am 0.7------ N/A 2.8
2024-11-20 06:10 am 1.0 0.3 5.6ESE 0.7 2.6 NW N/A 2.8
2024-11-20 05:40 am 1.0 0.3 4.5ESE 1.0 2.7 WNW N/A 2.8
2024-11-20 05:10 am 1.0 0.3 5.6 SE 0.7 2.7 WNW N/A 2.8
2024-11-20 04:40 am 1.0 0.3 5.6ESE 1.0 2.9 WNW N/A 2.8
2024-11-20 04:10 am 1.0 0.3 6.2ENE 1.0 2.9 WNW N/A 2.9
2024-11-20 03:40 am 1.0 0.3 5.9ESE 1.0 2.9 WNW N/A 3.0
2024-11-20 03:10 am 1.0 0.3 5.9ESE 1.0 2.9 NW N/A 2.9
2024-11-20 02:40 am 1.0 0.3 5.6ESE 1.0 2.9 WNW N/A 2.9
2024-11-20 02:10 am 1.0 0.3 5.0ESE 1.0 2.6 WNW N/A 2.7
2024-11-20 01:40 am 0.7------ N/A 2.6
2024-11-20 01:10 am 0.7------ N/A 2.8

Plot of wave energy versus frequency (and period)