Q: Why are there global models and regional models?

Global models (such as GFS or ECMWF) cover the entire planet. They are essential for long crossings and long-term forecasts (up to 10–15 days), but their resolution remains limited (20 to 50 km). They are used to get an overall view of the weather and for long-distance passages. Regional models focus on a specific area (France, Europe, the Mediterranean…). Their coverage is smaller, but their resolution is much finer (2 to 10 km), allowing for better anticipation of local effects such as thermal breezes, thunderstorms, terrain, and coastal winds. In return, they generally only extend 2 to 3 days into the future. They are used for day trips or short cruises.

Question 1

What regional atmospheric models are available outside Europe?

Henri · Accepted Answer

NavimetriX offers several high-resolution regional models for popular sailing destinations worldwide, in addition to global models like GFS, ECMWF, and ICON Global.

North America

NAM (11 km resolution) — NOAA's North American Mesoscale model covers the continental United States. Forecasts up to 84 hours with hourly time steps. Ideal for coastal navigation along the US East Coast, West Coast, and Gulf of Mexico.

HRRR CONUS (3 km resolution) — The High-Resolution Rapid Refresh model provides the finest resolution for the continental US. Forecasts up to 18 hours, updated hourly. Perfect for racing and detecting rapidly evolving conditions like sea breezes and thunderstorms.

Caribbean & South America

Arome Antilles (3 km resolution) — Météo-France model covering the Lesser Antilles from Puerto Rico to Trinidad. Forecasts up to 48 hours. Excellent for inter-island passages and detecting trade wind variations.

Arome Guyane (3 km resolution) — Covers waters off French Guiana and the nearby South American coast. Forecasts up to 33 hours. Useful for sailors transiting between the Caribbean and Brazil.

Pacific Islands

Arome Polynésie (3 km resolution) — Covers French Polynesia including Tahiti and the Society Islands. Forecasts up to 48 hours. Ideal for detecting local effects around high volcanic islands and reef passes.

Arome Calédonie (3 km resolution) — Covers New Caledonia and the Coral Sea. Forecasts up to 48 hours. Essential for navigating the lagoon system and anticipating thermal effects around Grande Terre.

Indian Ocean

Arome Réunion-Mayotte (3 km resolution) — Covers the western Indian Ocean from the Mozambique Channel to the Mascarene Islands, including Madagascar, Réunion, Mauritius, and Mayotte. Forecasts up to 48 hours. Critical for this cyclone-prone region.

Read also: Why are there global models and regional models

Question 2

What regional atmospheric models are available outside Europe?

Henri · Accepted Answer

NavimetriX offers several high-resolution regional models for popular sailing destinations worldwide, in addition to global models like GFS, ECMWF, and ICON Global.

North America

NAM (11 km resolution) — NOAA's North American Mesoscale model covers the continental United States. Forecasts up to 84 hours with hourly time steps. Ideal for coastal navigation along the US East Coast, West Coast, and Gulf of Mexico.

HRRR CONUS (3 km resolution) — The High-Resolution Rapid Refresh model provides the finest resolution for the continental US. Forecasts up to 18 hours, updated hourly. Perfect for racing and detecting rapidly evolving conditions like sea breezes and thunderstorms.

Caribbean & South America

Arome Antilles (3 km resolution) — Météo-France model covering the Lesser Antilles from Puerto Rico to Trinidad. Forecasts up to 48 hours. Excellent for inter-island passages and detecting trade wind variations.

Arome Guyane (3 km resolution) — Covers waters off French Guiana and the nearby South American coast. Forecasts up to 33 hours. Useful for sailors transiting between the Caribbean and Brazil.

Pacific Islands

Arome Polynésie (3 km resolution) — Covers French Polynesia including Tahiti and the Society Islands. Forecasts up to 48 hours. Ideal for detecting local effects around high volcanic islands and reef passes.

Arome Calédonie (3 km resolution) — Covers New Caledonia and the Coral Sea. Forecasts up to 48 hours. Essential for navigating the lagoon system and anticipating thermal effects around Grande Terre.

Indian Ocean

Arome Réunion-Mayotte (3 km resolution) — Covers the western Indian Ocean from the Mozambique Channel to the Mascarene Islands, including Madagascar, Réunion, Mauritius, and Mayotte. Forecasts up to 48 hours. Critical for this cyclone-prone region.

Read also: Why are there global models and regional models

Question 3

Why are there global models and regional models?

Henri · Accepted Answer

Global models (such as GFS or ECMWF) cover the entire planet. They are essential for long crossings and long-term forecasts (up to 10–15 days), but their resolution remains limited (20 to 50 km). They are used to get an overall view of the weather and for long-distance passages.

Regional models focus on a specific area (France, Europe, the Mediterranean…). Their coverage is smaller, but their resolution is much finer (2 to 10 km), allowing for better anticipation of local effects such as thermal breezes, thunderstorms, terrain, and coastal winds. In return, they generally only extend 2 to 3 days into the future. They are used for day trips or short cruises.

Question 4

Which NMEA0183 XDR sensors can I use?

Henri · Accepted Answer

FAQ - NMEA0183 XDR Sentence (Transducers)

What is the XDR sentence?

The XDR (Transducer Measurement) sentence is a generic NMEA0183 sentence used to transmit measurements from various types of sensors (transducers). It allows multiple measurements to be grouped into a single sentence.

What is the general format of the XDR sentence?

$xxXDR,a,x.x,u,n,a,x.x,u,n,...*hh

Where for each transducer group:

a: Transducer type (one letter)
x.x: Measured value
u: Unit of measurement (one letter)
n: Transducer name (character string)

The checksum (*hh) is mandatory.

Which transducers are supported by NavimetriX?

1. Heel/Pitch

Field	Value
Type	`A` (Angular)
Unit	`D` (Degrees)
Name	`PTCH`

Example:

$IIXDR,A,5.2,D,PTCH*XX

This indicates a pitch angle of 5.2°.

2. Roll

Field	Value
Type	`A` (Angular)
Unit	`D` (Degrees)
Name	`ROLL`

Example:

$IIXDR,A,-1.1,D,ROLL*XX

This indicates a roll angle of -1.1°.

Combined example (Roll + Pitch):

$IIXDR,A,-1.1,D,ROLL,A,5.0,D,PTCH*74

3. Water Temperature

Field	Value
Type	`C` (Temperature)
Unit	`C` (Celsius), `F` (Fahrenheit), or `K` (Kelvin)
Name	Must contain `water` (e.g., WATERTEMP, WaterTemp, water)

Examples:

$IIXDR,C,18.5,C,WATERTEMP*XX
  $IIXDR,C,65.3,F,WaterTemp*XX
  $IIXDR,C,291.65,K,water*XX

4. Air Temperature

Field	Value
Type	`C` (Temperature)
Unit	`C` (Celsius), `F` (Fahrenheit), or `K` (Kelvin)
Name	Must contain `air` (e.g., AIRTEMP, AirTemp, air)

Examples:

$IIXDR,C,22.0,C,AIRTEMP*XX
  $IIXDR,C,71.6,F,AirTemp*XX

Combined example (Water + Air):

$IIXDR,C,18.1,C,WATERTEMP,C,22.0,C,AIRTEMP*49

5. Barometric Pressure

Field	Value
Type	`P` (Pressure)
Unit	`B` (Bars)
Name	Must contain `baro` (e.g., BARO, Barometer, baro)

Note: The value must be expressed in Bars (1 bar = 1000 hPa). NavimetriX automatically converts it to hPa.

Example:

$IIXDR,P,1.013,B,BARO*XX

This indicates a pressure of 1013 hPa.

How do I combine multiple measurements in a single sentence?

Transducer groups can be chained in the same XDR sentence (up to 10 transducers per sentence):

$IIXDR,A,-2.5,D,ROLL,A,3.1,D,PTCH,C,18.5,C,WATERTEMP,C,21.0,C,AIRTEMP,P,1.015,B,BARO*XX

Is the transducer name case-sensitive?

No. Transducer name recognition is not case-sensitive for temperatures and pressure:

WATERTEMP, WaterTemp, watertemp → all recognized
AIRTEMP, AirTemp, airtemp → all recognized
BARO, Barometer, baro → all recognized

Exception: For roll and pitch, the names must be exactly ROLL and PTCH.

Which talker prefix should I use?

NavimetriX accepts all standard talker prefixes (II, GP, HC, etc.). The examples above use $II (Integrated Instrumentation), but $GP, $HC, or others are equally valid.

Summary of accepted formats

Measurement	Type	Unit	Transducer Name
Pitch	A	D	`PTCH`
Roll	A	D	`ROLL`
Water temperature	C	C, F, or K	contains `water`
Air temperature	C	C, F, or K	contains `air`
Barometric pressure	P	B	contains `baro`

What regional atmospheric models are available outside Europe?

What regional atmospheric models are available outside Europe?

North America

Caribbean & South America

Pacific Islands

Indian Ocean

Contact

Politique de confidentialité

Conditions Générales d’utilisation

What regional atmospheric models are available outside Europe?

What regional atmospheric models are available outside Europe?

North America

Caribbean & South America

Pacific Islands

Indian Ocean

Related Posts

Why are there global models and regional models?

Which NMEA0183 XDR sensors can I use?

Which NMEA0183 XDR sensors can I use?

Quels modèles atmosphériques régionaux sont disponibles hors d’Europe ?

Contact

Politique de confidentialité

Conditions Générales d’utilisation