NOAA / Space Weather Prediction Center

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History and Announcements

July 25, 2012 -- New G-based Watches are implemented

Effective Wednesday, July 25, 2012, at 1600 UTC (10:00 AM MDT), SWPC will modernize its geomagnetic storm watch products. These products will now be issued relative to the highest expected geomagnetic storm category (NOAA Scale) and will be based on the 3-hour geomagnetic K-index rather than the 24-hour A-index. Watch products will still be valid for the entire UTC day, just as they are under the A-based watches today. This change will better align SWPC’s geomagnetic watch products with its geomagnetic warning and alert products and NOAA Scale designations. Product Subscription Service customers are not required to take any action regarding this change. The current A-based watches contain expected geomagnetic storm scale (G-level) information so all subscriptions will be automatically transferred to the new G-based watch products.

For more information, please see the NWS Service Change Notification at
or contact SWPC Customer Support at

November 1, 2010 -- SWPC will no longer issue Proton Alert Continuations.

April 13, 2007 -- The SEC designated primary GOES satellite for X-rays changed from GOES 12 to GOES 11. See GOES Data at SEC for more details.

February 9, 2005 -- SEC has a new Product Subscription Service (PSS) for email delivery of our products

The PSS system replaces the Majordomo List Server and the Space Weather Alerts email service. Both older services will continue through April 2005, but new subscriptions are not being accepted.

PSS is an online, interactive system that allows you to register and then subscribe to the wide variety of email space weather products. There are even new products. Go to and register as new user. Then subscribe to one or more products.

Nov 24, 2004 -- The Stratwarm alert service provided by the NOAA Space Environment Center (SEC) will end on 01 December 2004.

SEC was informed that the Free University of Berlin (FUB) will no longer issue stratwarm alerts. The Berlin group was the responsible agency for developing and issuing this product. The stratwarm alerts were sent to SEC who, in turn, issued the alert to interested customers. The alert was also appended to the Joint USAF/NOAA Solar and Geophysical Activity Summary (SGAS), and the International Space Environment Service (ISES) GEOALERT.

The daily development of the stratospheric circulation can still be found on the FUB web site ( The general evaluation is, however, left to the user.

On October 19, 2004 the NOAA Scale keywords were added to Space Weather Alerts.

On March 12, 2002 SEC's New Space Weather Alerts were implemented, replacing the old format alerts.

February 11, 2002


Beginning February 11, 2002, an operational preview of SEC's new Space Weather Alerts is available online. The new Watches, Warnings, Alerts, and Summaries are being issued in parallel with the current operational products, based upon prevailing space weather conditions and event criteria.

These new products are being issued to the SEC web site only, on a time-permitting basis with priority given to the current operational products. Users can visit the web site periodically, to preview the new products and formats, in comparison to those based on current operations. In cases where new or different criteria apply to new products, they are being issued accordingly. For further information on the new products and criteria, please refer to the Space Weather Alerts Description.

The scheduled date for full implementation of the new system, when the new products will replace current ones on all delivery systems, is: MARCH 12 at 1700 UTC.

NO RE-REGISTRATION FOR THE PRODUCTS YOU CURRENTLY RECEIVE WILL BE REQUIRED! Prior to the March 12 implementation date, customers who presently receive affected products will get individual notifications of changes to their product subscriptions that will be implemented with the new system.

November 15, 2001

You may have noticed a general announcement in our most recent SEC User Notes newsletter, regarding proposed changes to the space weather alerts products (including Watches, Warnings, Alerts, and Summaries) issued by the NOAA Space Environment Center (SEC). This message is a reminder for all interested customers to review the online documentation.

Essential features of the proposed changes are as follows:

Your comments on this proposed change are welcome through November 2001.

The exact implementation date for the new products is to be determined, but our target implementation period is for January, 2002. The exact date will be posted on the online documentation, and announced to all customers via a similar message.

PLEASE NOTE: NO RE-REGISTRATION FOR THE PRODUCTS YOU CURRENTLY RECEIVE WILL BE REQUIRED! For all products you currently receive, you will instead receive the new, equivalent products via the same delivery method you presently do, automatically after the implementation date.

November 15, 2001

Geomagnetic Indices Warnings/Alerts Changes

You have received a general notice regarding proposed changes to the space weather alerts products (including Watches, Warnings, Alerts, and Summaries) issued by the NOAA Space Environment Center (SEC). This message is in regards to the proposed discontinuation of our A-index Warnings and Alerts products which you may currently receive.

The details of this proposed change are described below:

With the planned implementation of new product formats, the NOAA Space Environment Center (SEC) proposes to eliminate all Warnings and Alerts based on the running, 24 hour geomagnetic A-index derived from USGS Boulder magnetometer data. However, Watches for 24 hour A-index values (at >=20, 30, 50, and 100 thresholds) will continue to be issued, as general indicators of longer term (e.g. one day or greater lead time) expectations for geomagnetic activity, based on daily forecasts issued by SEC.

At the present time, the vast majority of SEC Alerts customers subscribe to both A-index and K-index products. The A-index Warnings and Alerts are essentially redundant, when considered against the newly available Warnings and Alerts based on the 3 hourly K-index.

Any given A-index value is a result of cumulative geomagnetic activity over a 24-hour period, for which eight separate, 3-hour K-index values also apply, and essentially define the A-index. Changes in the running, 24 hour A-index can be driven by many varied combinations of K-index values. For example, an equal mix of eight values with K=3 and 4, versus a period with seven values of K=1 followed by a single value of K=7 (say, from a sudden storm
commencement), would both yield a 24-hour A-index value of 20, but would represent vastly different geomagnetic effects. Since Warnings and Alerts on the 3 hourly K-index value are to be further improved with near-real time issue, a more timely mechanism for reporting on persistent vs. sporadic behavior of the geomagnetic field will now be available to customers that are variously affected by such types of activity.

K-index product description is available online.

The Boulder (and estimated Planetary) A-index values, updated every 3 hours, will be available on improved NOAA-SEC web site pages, along with K-index values, for the benefit of customers who may wish to track the evolution of A-index values, after having received the more timely Warnings and Alerts based on K-index activity.

The elimination of A-index products further streamlines the operations involved in issuance of products, particularly during times of ongoing geomagnetic storm conditions.

SEC recommends the following changes for current A-index product customers:

No changes required.

A >= 20 should move to the K=4, 5, 6, >=7 lists
A >= 30 should move to the K=5, 6, >=7 lists
A >= 50 should move to the K=6, >=7 lists

A >= 20 should move to the K=4, 5, 6, 7, 8, 9 lists
A >= 30 should move to the K=5, 6, 7, 8, 9 lists
A >= 50 should move to the K=6, 7, 8, 9 lists

November 15, 2001

Particle Event Alert Changes:

You have received a general notice regarding proposed changes to the space weather alerts products (including Watches, Warnings, Alerts, and Summaries) issued by the NOAA Space Environment Center (SEC). This message is in regards to the proposed changes in criteria for issuing >2MeV electron flux alerts, which you may presently receive. Electron Flux Alert description is available online.

The details of this proposed change, due to the strong diurnal pattern of electron flux at geosynchronous orbit, are described below:

Current procedures call for the use of GOES-8, located in geosynchronous orbit at 75W (local noon = 1700 UTC), as the primary source of data for issuing Electron Alerts when the 2 MeV Integral Flux exceeds 1000 pfu. Upon initial detection, subsequent Alert "Continuations" are currently issued shortly after 0000 UTC on each succeeding day, IF the electron flux observed on the PRIOR day was at levels above threshold. When the levels fail to exceed threshold, the issue of these "continuations" ceases.

The proposed new criteria is to issue one Electron Alert per "satellite day" approximately 0500 to 0500 UTC for GOES-8), at the time when electron fluxes are confirmed to have exceeded event threshold (1000 pfu) for that day. On subsequent "days", an additional Electron Alert will be similarly issued upon a new threshold crossing, and will include information on the prior day's maximum flux time and value observed on GOES-8 (if it occurred). No Alerts will be issued for any "day" when the threshold is not exceeded. This procedure will replace the current "continuations" described above, as well as provide additional information about maximum flux observations over the course of an Electron Event. As with any electron event, users will have to consider the locations of their platforms of interest (vs. the location of GOES-8), with regard to the specific timing of enhanced electron exposures that may occur.

Please also refer to the details of the new, higher threshold products that will be introduced for Proton Events.

Updated: October 1, 2007