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EIDWS - METOC Cheat Sheet by

Ocean Eddies

Indepe­ndent circul­ations of cold or warm water
Generally found on either side of strong currents such as the Gulf Stream or Kuroshio
Used tactically by submarines because of the sound propag­ation differ­ences that exist inside and outside the eddie circul­ations

Wave Height

The vertical distance from the crest of a wave to the trough of the wave


The current that flows toward the shore with a rising tide

3 Types of Currents

Open Ocean

Spilling Breaker

Occur w/ Gentle Flat Beaches

Plunging Breaker

Occur w/ Moderate to Steep sloping Beaches

Four Major Ocean Sediments

Glacial Marine


Sound Speed increases 2 feet/s­econd for every increase in depth of 100 feet
Dominant controller of speed below 1000 feet in the ocean

Small Craft Warning

Winds Sustained at 18-33 knots
Forecasted for harbors and inland waters

Tropical Cyclone Conditions of Readiness - TCCOR

TCCOR 5 - Destru­ctive winds are possible within 96 hours
TCCOR 4 - Destru­ctive winds are possible within 72 hours
TCCOR 3 - Destru­ctive winds are possible within 48 hours
TCCOR 2 - Destru­ctive winds are antici­pated within 24 hours
TCCOR 1 - Destru­ctive winds are occurring or antici­pated within 12 hours

Defense Meteor­olo­gical Satellite Program - DMSP

LEO, Polar Orbiting Satellites
6 satellites in orbit

Wind Direction

Average direction from which wind is blowing

Air Mass

Body of Air over a Large Area
Takes on charac­ter­istics of the Underlying Surface
Temper­ature and Moisture Charac­ter­istics are the Same

Tropical Depression

An organized system of clouds and thunde­rstorms with a defined, closed surface circul­ation and maximum sustained winds of less than 34 knots

Cold Eddy

Cold Eddies form on the south side of the Gulf Stream and maintain a counte­rcl­ockwise circul­ation


The types are sheet, spark, and glowing ball.
Most biolum­ine­scence in the oceans is sheet-type
Spark-type displays are created by large numbers of crusta­ceans
Glowing ball displays are seen most frequently in warmer waters. Lumine­scent jellyfish cause many glowin­g-ball displays

Littoral Longshore Currents

Caused by Waves Approa­ching the Beach at an Angle
Increase Velocity with Increased Breaker Heights
Steep Beaches have stronger currents

Surging Breaker

Occur w/ Very Steep Sloping Beaches and are dangerous for Landing Craft

3 Thermal Layers of the Ocean

Mixed/­Surface Layer
Deep Layer


Sound Speed increases 4 feet/s­econd for every increase in salinity of 1ppt
Effects are greatest for Ocean water in areas of high evapor­ation and high influxes of fresh water

Gale Warning

Winds Sustained at 34-47 knots
Forecasted for harbors, inland waters, ocean areas, instal­lat­ions, and air fields

the Nautical Almanac

Contains the following data tabulated at hourly intervals to a precision of 0.1 arc minute: the Greenwich hour angle and declin­ation of the Sun, Moon, and naviga­tional planets; the Greenwich hour angle of Aries; positions of the naviga­tional stars; rise and set times of the Sun and Moon for a range of latitudes

Geosta­tionary Operat­ional Ent'l Satellites - GOES

24/7 Coverage over the same Geographic Region
Monitors weather systems and storms
4 GOES Satellites in Orbit

Relative Humidity

Percentage of the amount of water in the air compared to how much water can actually be held based on temper­ature & pressure

Warm Front

Replaces Colder Air

Tropical Storm

A distinct rotation must exist around the central area of low pressure and wind speeds must be between 34 and 63 knots. At this point the tropical storm is given a name.

Warm Eddy

Warm Eddies form on the north side of the Gulf Stream and drift into the colder waters of the Labrador Current mainta­ining their clockwise rotation

Sea Waves

Also known as wind waves, are waves generated by the wind in the local area

Wave Period

The time it takes for a complete wave cycle (crest to crest or trough to trough) to pass a given point

Open Ocean Currents

Major Currents like the Gulf Stream and Kuroshio

3 Breaker Types


Ocean Fronts

Interface btwn 2 Water Masses of Different Temper­atures and Salinities

Mixed/­Surface Layer

Isothermal Temper­ature with Depth
From the ocean surface to about 1500 feet


Primary Controller of Sound Speed in the top 1000 feet of the ocean
Sound Speed increases 6 feet/s­econd for an increase in 1 degree centigrade

Storm Warning

Winds Sustained at 48 knots and greater
Forecasted for harbors, inland waters, ocean areas, instal­lations and airfields

the Astron­omical Almanac

Contains precise epheme­rides of the Sun, Moon, planets, and satell­ites, data for eclipses and other astron­omical phenomena for a given year

Polar Operat­ional Ent'l Satellites - POES

A.K.A. TIROS-N Satellites
Collects Data Globally
There are 6 POES Satellites in orbit

Wind Speed

Average rate of air motion
Measured in nautical miles/hour or Knots

Cold Front

Displaces Warm Air at the Surface

Restricted Visibility

Prevailing Visibility falls below 7 Nautical Miles or 10 Statute Miles


Wind speeds must be at least 64 knots

Thunde­rstorms - TS

Formed when cumulous clouds grow into cumulo­nimbus clouds

Bathyt­her­mograph - BT

The measur­ement and recording of subsurface water temper­ature at various depths
BT data is the critical factor in determ­ining the sound velocity profile (SVP) of a particular ocean area

Swell Waves

Waves that have moved away from the area in which they were formed


The current that flows away from the shore with a falling tide

Rip Currents

NOT Associated w/ Tides
Caused by return flow of water from the beach
Form at the end of a beach where land juts out into the water

5 Major Ocean Provinces

Contin­ental Shelf
Contin­ental Slope
Contin­ental Rise
Ocean Basins
Mid-Ocean Ridges


Describe by its rapid decrease in temper­ature with depth from the layer above it


METOC data is a layer of Geospatial Intell­igence and is critical to planning and operations in the joint enviro­nment

Severe Thunde­rstorm Warning

TS are w/in 10NM or an hour away
Gusts of 50 kts or Greater = 3/4" Hail and/or Tornadoes

Nat'l Polar Orbiting Ent'l Satellite System­-NPOESS

Will Replace the POES and DMSP

Tropical Rainfall Measuring Missio­n-TRMM

Joint venture btwn NASA and Japanese Nat'l Space Develo­pment Agency
Research the water cycle in the atmosphere


Transi­tions between two Air Masses


Suspension of small water droplets or ice crystals in the air that reduces visibility at the surface


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