A few of the IFS’s 101 members have a zonal wind reversal too — but not the majority. 18Z GFS equivalent to a single ensemble member scenario charts.ecmwf.int/products/ext...

Not sure if it's more effective, just that it seems more common. Wave-2 events usually need more preconditioning through the winter.

Still beyond 2 weeks out so will fluctuate a fair bit, especially now we have daily runs so can see every little wiggle

Evolution of these forecasts is pretty wild simonleewx.com/ecmwf_north_...

I don’t know if that statement is generally true but if you have a look at forecasts on my website, it seems true of late with adjustment away in recent runs

BUT all that said, tropospheric forecasts seem to have been overconfident in Pacific Trough regime persistence recently and are now drifting away from that... so quite possible vortex forecast shifts

Early season weakening/warming tends to be more over Canada/N Pacific as this is mostly wave-1 driven, which is the primary mode in early season

Wave-1 amplitude is exceptional for the time of year in GEOS forecasts acd-ext.gsfc.nasa.gov/Data_service...

Thanks! There appears to be quite a lot of deep cyclones coming off W Asia/N Pacific, which can drive enhanced vertical wave activity due to constructive interference with wavenumber-1. We're also in an established EQBO which favours early season weakening.

I don't know enough about hurricane dynamics, I'm afraid! Sometimes a lack of forward movement can weaken a storm due to cold upwelling, but that doesn't seem to be an issue at all here. Perhaps @jakecarstens.bsky.social has some thoughts!

Yup.