Chris Weijenborg

Although main findings are very similar as for winter cyclones, we did find more continental moisture sources and that there is (relatively) less exchange between primary and secondary cyclones. Moreover, we find a stronger influence of cyclones undergoing an extratropical transition.

Precipitation, Moisture Sources and Transport Pathways associated with Summertime North Atlantic Deep Cyclones Abstract. Extratropical cyclones are essential for redistributing moisture from lower latitudes to the poles, and are known for their ability to produce (extreme) precipitation. While wintertime extra...

In a new preprint on a study lead by Rikke Stoffels, we looked at the pathways and moisture sources of these summer cyclones, which received less attention than their winter counterpart. #precipitation #cyclones #moisturesources egusphere.copernicus.org/preprints/20...

I understand your frustration! I hope you can resubmit it, or can submit it somewhere else.

Yes, ideally you have some pressure gradient (e.g. Laplacian) or vorticity based intensity measure which should work better in both the cyclostrophic and geostrophic limit.

The pressure is also dependent on the latitude and a smaller cyclone of the same minimum pressure is much more intense as a cyclone with the same minimum pressure but twice that large.

Impact will probably/hopefully be less, also because the region of strongest winds south of #Herminia seem to pass south of Ireland.

#StormEowyn is off to Norway, but the next one in the train of the same cluster of cyclones is approaching Ireland tomorrow, named #Herminia by the Spanish met service. Looks again a bit more a Shapiro-Keyser type cyclone, though this is less clear as that compared to Eowyn.

Agreed as well, but this is the case for many diagnostics we use, like wavier or not wavier jets, influence of stratosphere interaction (there is also still debate on that: when can we really prove the stratosphere influenced the troposphere), atmospheric rivers, or my own topic cyclone clustering.

I know, but I meant also that this is mainly of interest from a scientific (and possibly modelling) point of view and probably less of interest for the general public.

Voor alle Nederlandse meteorologen met interesse in modelleren:

I think the whole terminology is a bit confusing, if both the synoptic airflow as well possibly mesoscale sting jet play a role in forming the wind maximum, how can you separate the two? But don't know if we need another term for the combination of the two.

Which cyclone does completely follow the evolution depicted by either the Norwegian or Shapiro-Keyser model? Given its frontal evolution I would say it is clearly more a SK cyclone.

The intensity & structure of #StormÉowyn were certainly conducive to sting-jet descent. This satellite image would be consistent with it, as would be the timing and location of the record gust. However, we can't yet say whether the cold conveyor belt also played a role there 1/2

#StormÉowyn's development continues.

What in most cyclones of this type is at this stage a dry slot, is more of a dry sea within the centre of circulation.

Into it, air is descending from aloft & there's a chance of a 'sting jet' establishing at the cloud hook end (www.rmets.org/metmatters/w...).

The main issue is that the cyclone reaches maximum intensity just before it hits Ireland. Hope for the best and not too many problems.

Is this median gust from the ensemble the best predictor to your experience or would you rather go lower/higher?

Airmass (theta-w) forecast of ICON-EU for the storm to hit Ireland soon

#StormEowyn is predicted to intensify rapidly until reaching Ireland. Still some spread but most models agree with wind gusts up to 200+ km/hour (Arome as well) at land fall in Ireland, possibly related to a sting jet.

The next cyclone developing along the same jet streak is already predicted a few days later until Sunday, though it seems less intense than #Eowyn for now.

Very interesting case of cyclone clustering coming up at the end of the week. The atmospheric jet stream already intensified along the east coast of the USA/West Atlantic, which leads to the rapid deeping of
#StormEowyn later this week. Quite often these intense cyclones are warm core cyclones.

What is also interesting is quite often warm core cyclones (more like the Shapiro Keyser like evolution), which is also the case for #StormEowyn and seems to be happening again for the following cyclone as well which develops in the night till Sunday.

Choosing a default colour bar can be quite tricky, though 28 m/s might be a bit low for the extreme cases.

Soms moet je als politicus lege handen accepteren om te voorkomen dat je met te vuile handen achterblijft.

Dat klopt ja, ik had het eigenlijk ook vooral over Nederland (al was dat niet duidelijk in mijn vorige post). De zon is hier ook een aangename afwisseling in het grijze eind november.

The Response of Extreme Jet Stream Waviness on Large-Scale Spatial Warming on an Aquaplanet - Thomas J. Batelaan - UP3.2 This talk was given at the EMS Annual Meeting 2024 in Barcelona during the Session UP3.2 - Mid-latitude atmospheric teleconnection dynamics. …

Also interesting is the talk of Thomas Batelaan on the (lack) of changes in jet stream waviness in aquaplanet simulations:
vimeo.com/showcase/114...
Also available as paper at GRL:
agupubs.onlinelibrary.wiley.com/doi/full/10....

Helaas/Gelukkig (doorhalen wat niet van toepassing is) niet meer zo warm als vorige week.

I gave a presentation on this at the EMS in Barcelona last September, all the talks are now available online, this is the link to mine:
vimeo.com/showcase/114.... This talk includes also some thoughts on the relation to storm track biases and future changes which is not in the preprint.

Aluminium hoedje - Wikipedia

Ter bescherming tegen gedachtenlezen door de mens? nl.wikipedia.org/wiki/Alumini...

Dat wel, maar gisteren was het volgens mij nu nog vrij onzeker hoe sterk de wind(stoten) nu zou(den) worden. Een Eunice bijvoorbeeld in februari 2022 zat er ook al een week van te voren in (al was dat redelijk uitzonderlijk).

Het interessante is dat het de afgelopen dagen nog steeds vrij onzeker was hoe sterk Collan nu zou worden. Het leek eerst niet heel indrukwekkend te worden.