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<p><font face="DejaVu Sans">There was one run which failed to
converge. Ie the model got into a loop where instead of each
step getting closer to a solution the results started to diverge
again. This leads to a model crash.</font></p>
<p><font face="DejaVu Sans">It is caused by an anomaly in the input
data - often associated with unusual weather events like "cut
off lows" (but that was not the cause of recent crashes).
This coupled with compromises made when the model was
constructed makes the model run crash. It happens on a handful
of runs a year.</font></p>
<p><font face="DejaVu Sans">In order to avoid this, the model would
have to have smaller "time step" intervals and/or a smaller
"resolution ratio" ie 12km -> 4km -> 1.3km. That would
make it run slower and use more computer time and electric
power. The parameters selected were a compromise that work most
of the time.</font></p>
<p><font face="DejaVu Sans">When this happens I have seen the same
date forecast crash on subsequent forecasts runs, ie 1 day
ahead, night before etc.</font></p>
<p><font face="DejaVu Sans">If you see this, have a look at the
alternate model legacy vs beta. It is possible one crashes when
the other manages to resolve.</font></p>
<p><font face="DejaVu Sans">Regards</font></p>
<p><font face="DejaVu Sans">Ian</font></p>
<p><font face="DejaVu Sans"><br>
</font></p>
<div class="moz-cite-prefix">On 4/8/26 20:40, AirSchool Paragliding
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAPKYDukPiNb+hWhGodoEFu4nkaN2WJOONwPdxcxFk8gQbDhbkQ@mail.gmail.com">
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<div dir="ltr">Greetings all<br>
<br>
Just noticed that a few <span class="Asgive ng"
style="border-style:none;background:none">of the </span>RASP
days haven't been updated since yesterday e.g. RASP 1.3km d0 and
d2, RASP 2km d4 and d5<br>
<br>
Many thanks<br>
Ria</div>
</blockquote>
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