WA8LMF Home Page | Get NWS ShapeFiles | Main APRS Page | Updated  26 December 2009


Reasons For The Reduced Volume Of Weather Data On The APRS-IS

25 December 2009

The following is an excerpt of an email between Randy (WF5X) and the current owner/maintainer  of the APRS-IS weather server.   In mid-summer 2009, this server replaced the older one that put everything from the NWS into the APRS-IS system. Lines that begin with > are from me; all non-marked lines are from the wxsvr owner/maintainer (AE5PL).

PLEASE, read this a few times and understand what isn't put put out by the current wxsvr and why, and that a good part of what we aren't seeing is due to a procedure policy of the NWS, not the wxsvr maintainer.

/begin quote/

> I'm sure you are aware of all the buzz on the APRSSIG and UIVIEW lists
> about how the wxsvr isn't working. The biggest gripe from people right
> now is that they aren't seeing the winter weather warnings. I'm sure
> that the primary reason is that you aren't parsing the event code from
> the NWS stream for those. A big part of that is that the NWS lumps a

No, the reason they are not being put on APRS-IS is because they are not (according to the NWS) Immediate, Actual, Meteorological alerts.  The reason the NWS does not classify them this way is because there is no immediate identification in a winter weather warning, a flood warning, a watch, a special weather statement, etc.  To qualify as an immediate, actual alert, the NWS office determines that there is an immediate, identifiable threat to life or property in a specific area.  This includes Severe Thunderstorm Warnings, Tornado Warnings, and Flash Flood Warnings.

> good part of the winter stuff under the same code of WSW and you were
> wishing to limit the wxsvr to warning messages only. I am asking you to
> consider adding the WSW and BZW event codes as valid for passage by
> the wxsvr in order that winter storm warning and blizzard warnings are
> passed along to the APRS-IS.

APRS-IS #1 primary purpose is to support APRS on RF; not APRS on the Internet.  I used this statement to determine the criteria for publishing weather alerts on APRS-IS.  As stated above, it has nothing to do with type of warning.  The only criteria used are if the local weather office determines the alert is Immediate and Actual in nature (this is their terminology and ratings, not mine).  Generic warnings such as winter weather, blizzard, etc. are wide-area events that are best disseminated via reliable sources such as weather radio, commercial radio, TV, and the Internet just as watches and special weather statements are dispensed.  The reason for the Immediate and Actual criteria allowing dissemination to APRS-IS is because:

It will not congest an RF channel and all NWS alerts gated to APRS-IS are important so they should be looked at immediately as they may affect a mobile or remote operator's safety.

I know Dale (note: Dale was the person that maintained the old WXSVR ) had a lot of heartburn over the excessive amount of information his weather server was pumping into APRS-IS and therefore onto local APRS channels.  I decided to take a "learn from past experience" approach and focus on information that is vital to a field APRS operator that may not be available otherwise due to active operations in the mobile at the time.

/end quote/


The translation of this is that only LOCAL weather service issued warnings ( FFW, TOR, SVR event codes ) will be ported to the APRS-IS, due to the belief that having *ALL* NWS watch/warn/advis messages was causing too much local RF traffic *AND* that general area and broad coverage events such at blizzards, winter storms, hurricanes, and floods are best received via Internet or media sources including NOAA weather radio.

Flash Flood, Tornado, and Severe Thunderstorm Warnings are all LOCALIZED events that IMMEDIATELY affect safety of life and property. Many of the other warnings ( blizzard, winter storm, flood, hurricane, etc. ) are wide spread events that often have many *HOURS* of lead time to prepare for or react to them. Flash Flood, Tornado, and Severe Thunderstorm Warnings have lead times in the *minutes*, and thus warrant *immediate* dissemination by all means, including APRS.

Please note, there is nothing that precludes someone from creating these types of objects locally for their area and submitting them via RF. If you want to parse the NWS stream yourself for all information related to your locality, go right ahead. Just be mindful of the traffic you add to your local network in doing so.

I'm only the messenger, not the policy maker. Hope this sheds light on this "issue" for lots of people, and rest assured that your UI-NWS is working correctly *if* you have it set up according to the instructions located on this website:

  WA8LMF UIview Notes

Merry Christmas.