---
title: GEFS (NOAA/NCEP)
summary: The Global Ensemble Forecast System: the United States' ensemble built on the GFS, public domain.
mount: <div class="card"><p class="kicker">Models</p><div class="wx-scroll" tabindex="0"><svg class="mg" viewBox="0 0 994 96" width="994" height="96" role="img" aria-label="GEFS (NOAA/NCEP): what it is connected to"><style>.mg text{font:12px var(--sans);fill:var(--ink)}.mg .mg-sub,.mg .mg-verb{font-size:10px;fill:var(--ink-2)}.mg-node rect{fill:var(--surface);stroke:var(--line-2)}.mg-node.me rect{stroke:var(--focus);stroke-width:2}.mg-node.unstated rect{stroke-dasharray:2 3;fill:var(--paper)}a.mg-node:hover rect,a.mg-node:focus rect{stroke:var(--focus);stroke-width:2}.mg-edge{fill:none;stroke:var(--ink-2);stroke-opacity:.55;stroke-width:1}.mg-edge.unv{stroke-dasharray:5 4}</style><path class="mg-edge" d="M232 23C306 23 306 48 380 48"><title>stated on the page: nomads.ncep.noaa.gov</title></path><text class="mg-verb" x="240" y="19" text-anchor="start">carries</text><a class="mg-node " href="data-noaa-nomads.html"><rect x="2" y="8" width="230" height="30" rx="4"/><text x="9" y="21">NOAA NOMADS (NCEP model output)</text><text class="mg-sub" x="9" y="33">Open data and APIs</text></a><path class="mg-edge" d="M232 63C306 63 306 48 380 48"><title>stated on the page: emc.ncep.noaa.gov</title></path><text class="mg-verb" x="240" y="59" text-anchor="start">runs</text><a class="mg-node " href="body-noaa.html"><rect x="2" y="48" width="230" height="30" rx="4"/><text x="9" y="61">NOAA (NWS, NCEP, NESDIS)</text><text class="mg-sub" x="9" y="73">Bodies</text></a><g class="mg-node me"><rect x="380" y="33" width="230" height="30" rx="4"/><text x="387" y="46">GEFS (NOAA/NCEP)</text><text class="mg-sub" x="387" y="58">Models</text></g></svg></div><p class="wx-legend meta">Left: what points at it. Right: what it points at. Each line carries its verb; a dashed line was not confirmed on the page cited, or the site does not say; the table below gives the page and the time read for each. <span class="prov">From <a href="model-gefs.json">model-gefs.json</a></span></p></div>
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# GEFS (NOAA/NCEP)

> Kept by incident.meteorology@web-summit.dinis, 11 November 2026, 11:36 UTC

[Where a forecast comes from](../index.md) · Models · id `model-gefs` · [as data](model-gefs.json)

The Global Ensemble Forecast System: the United States' ensemble built on the GFS, public domain.

**Address:** [https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gefs.php](https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gefs.php) (leaves this site)

## What it is connected to, and who says so

| This | Verb | That | The page that says so | Read | Check |
|---|---|---|---|---|---|
| GEFS (NOAA/NCEP) | **is what NOAA NOMADS (NCEP model output) carries** | [NOAA NOMADS (NCEP model output)](data-noaa-nomads.md) | [nomads.ncep.noaa.gov](https://nomads.ncep.noaa.gov/): "description of each data access method. Data Set freq grib filter https Global Models AIGFS 6 hours - https AIGEFS 6 hours - https GDAS 6 hours grib filter https GDAS 0.25 6 hours grib filter https GFS 0.25 Degree 6 hour" | 11:29 UTC, 11 Nov | stated on the page |
| GEFS (NOAA/NCEP) | **run by** | [NOAA (NWS, NCEP, NESDIS)](body-noaa.md) | [emc.ncep.noaa.gov](https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gefs.php): "People Resources Visit Our Collaborative Space via VLAB Help Share --> Export --> Global Ensemble Forecast System Global Ensemble Forecast System (GEFS) --> To illustrate the use of ensemble based probabilistic forecast," | 11:29 UTC, 11 Nov | stated on the page |

## Licence: what we may do with it

No licence row yet covers this node: **unclear** until one does. [The licence table](../licences.md).

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Not a warning service: this page explains where data comes from. For warnings follow [IPMA](https://www.ipma.pt/pt/otempo/prev-sam/) and ANEPC.