[EAS] Improving weather alerts on WEA mobile devices

[Sean Donelan]

On Tue, 26 Feb 2019, Robert Bunge wrote:
> On Tue, Feb 26, 2019 at 3:12 PM Sean Donelan <sean at donelan.com> wrote:
>> messages. Some of NWS alerts are important for the public at home. But
>> most weather warnings are aimed at travelers getting home or work. There
>> isn't a good reason to mobile devices to sound the WEA Alarm in the middle
>> of the night waking people up at home for travel weather warnings. It just
>> annoys them and causes them to turn off all WEA warnings.
>
> I don't understand this.  I'm going to guess the majority of NWS' WEAs 
> are for flash floods, followed by Tornado warnings.  FFW's certainly 
> have an important home target audience.  Waking someone up in the 
> middle of the night for a TOR or FFW (also realize WEA would have been 
> triggered during the levee breech during Katrina, or any damn break) is 
> pretty critical.

NWS could do that, but NWS doesn't do that currently. NWS sets CMAS/WEA 
U-C-S values statically. Other alert originators just seem to be confused, 
and set all the values to the maximum.

My proposed change still has four-levels of weather alerts (low, medium, 
high and extreme). NWS could still use top levels to wake people 
up for levee breaches and use a low level for winter weather travel 
advisories. Most of the new NWS hazard simplification proposals have 
four-levels, so a four-level proposal for weather alerts seems to fit 
well.

The CAP "Certainty" value has no practical affect in the CMAS/WEA 
standards. The code exists, but doesn't actually do anything different in 
CMAS/WEA or any other country's mobile public warning system worldwide.

Here are the 7,190 types of WEA messages sent in 2017.

FFW	3485
TOR	2857
HUW	265
CAE	184
LAE	116
SSW	75
CEM	70
FRW	45
DSW	23
LEW	19
EVI	18
EWW	18
CDW	7
SPW	4
HMW	2
AVW	1
EQW	1

>> Because Weather Alerts are the biggest contributor to WEA, I propose
>> exchanging the CAP Certainty with the CAP Category "Met" (i.e.
>> meteorological) for WEA weather alerts. Coding WEA messages would enable
>
> I guess I'm not following why the category, which NWS already populates 
> with "Met" couldn't be used without any changes.

The CMAS/WEA protocol only extracts a few selected CAP elements. The 
existing CMAS/WEA over-the-air protocol does not include the CAP Category 
at all in the cell-broadcast message to mobile devices. Essentially all the 
CAP values are reduced to 15 code numbers in the UMTS/GSM/LTE 
transmission.

The Cell-broadcast channel is extremely bandwidth contrained, where each 
bit matters. Adding a bit to the cell-broadcast message, means removing a 
bit.

See appendix A in my filed comments.

> I think you are actually proposing that FCC require end user devices to 
> add a Met category and allow opt-out.  I know in the past round of 
> discussion, NWS asked FCC to look at standardization of the end user 
> devices interface and or options.  NWS experience had been the 
> differences in options in the WEA application was a source of end user 
> confusion and exposed NWS to a more complex support environment when the 
> public sought out help from the NWS.

Again, more details in my comments filed with the FCC.

> The full U-S-C suite, IMHO, offers a rich future one day, when NWS gets 
> to the point where even a seemly low level alert like a Winter Storm 
> Advisory could be set to trigger WEA if the event was going to have a 
> major impact, an example being light snow causing slippery roads right 
> at rush hour in a large metro area.

The fact that the "C" in U-S-C in the current CMAS/WEA protocol has no 
practical affect appears confusing to even warning system experts.
And after reviewing hundreds of WEA messages, the U-S-C matrix seems to be 
even more confusing to alert originators and not understood by the public 
at all.

Hence lots of confusing customer support calls.

Which combination of U-S-C (actually S-U-C in CMAS/WEA) does what in 
CMAS/WEA? Few people get it right without referring to a cheat sheet. And 
looking at hundreds of WEA messages, almost no alert originators know 
which S-U-C to use.

My proposed converts the existing eight alert levels in CMAS/WEA into 
four-levels of weather alerts and four-levels of non-weather alerts. 
Naming the four alert levels is something for social science and user 
interface design research. Lets call the four levels: low, medium, high 
and extreme imminent threats for now.

CAP and CMAS/WEA are different standards. Alert messages are translated 
between the two protocols by the IPAWS federal gateway. Its at that point 
the CAP severity, CAP urgency and CAP catagory="Met" would change.