leo2000

That was a strong El Nino that faded into a weak La Nina.

Yes, that looks to be happening and even if it gets mild somewhat in early January but that may not happen as models have been forecasting warm in the long range and it never materializes. I think we could have indeed some storm threats before Christmas and on Christmas itself.

I got the feeling we are going to have a early January thaw for the first two weeks of January then back to the colder pattern we had since late November into all of February.

Risky business to bet on the "coast to coast" ridge holding firm at the margins, as I've been warning @weathertrader (I'm hyping cold right now) Polar vortex anchored over Hudson Bay just needs a subtle nudge and it dumps out e.g. Day 12 (AI-GFS)

Interesting situation happening here the big warm up is being muted by the latest Euro Ensembles as the -WPO is fighting back. On the other hand the latest GEFS holds onto the big warm up and so does the GEPS.

I know many are down on this big warm up the up side however is this may actually offer a chance for a big coastal storm as the cold pattern relaxes.

They are too you can see the EPO ridge in Alaska high heights where before there was low heights. This could a trend GEFS 12z shows this.

A lot of people are forgetting all it takes is a transitional +PNA to get a big storm to pop on the east coast. Speaking about that models seem to be showing that on the 13th of December. I watch that period very closely for a miller b snowstorm.

Indeed a full blown blizzard

Yeah overall cold but I don't like seeing those low heights over Alaska ak vortex.

So we should expect the models to be getting colder?. For some reason the Ak vortex is still there plus the EPS this morning did not look that cold.

I don't buy the +EPO with MJO going in phase 8 along with the weak polar vortex. I do think a +PNA is coming.

Precip predictions

Confirms what I have been thinking (so far). We shall see though.

The data seems to show though that this SSW event is a combined reflective-absorptive sudden stratospheric warming event. The reflection phase allows for the Alaskan Ridge and a positive AO and positive NAO in the near term. Absorbing Phase: Subsequently, the stratosphere switches to an absorbing state, where it absorbs the upward wave energy, leading to a breakdown or weakening of the polar vortex. This absorption phase causes downward propagation of anomalous winds and is typically associated with a negative phase of the AO/NAM, leading to an increased likelihood of cold air outbreaks in mid-latitudes, particularly across North America and Eurasia. Tropospheric Impacts The distinct phases of a combined event lead to a sequence of different weather impacts on the Earth's surface: Near-term (Reflective Phase): Stronger westerlies and an active storm track across northern Europe may be observed, with temporary ridging in the North Pacific. Medium-term (Absorptive Phase): Increased pattern uncertainty emerges as the vortex breaks down, typically leading to the negative AO pattern and potential severe winter cold in mid-latitude regions. From Met Jens Bonewitz Stratospheric Update: hashtag#Potential Combined Reflective-Absorptive hashtag#SSW Developing! Following yesterday's discussion (link: https://lnkd.in/egEFCFuq), models continue to indicate persistent hashtag#wave-1 forcing on the stratospheric polar vortex (SPV) extending into December—this time driven primarily by an intensifying hashtag#Aleutian Low. We may be witnessing a combined or consecutive reflective-absorptive hashtag#SSW event. As discussed in the recent hashtag#Hannachi et al. (2025) paper, these complex events occur when upward propagating planetary waves first reflect off the disturbed vortex (creating negative heat fluxes that temporarily strengthen the SPV and accelerate the polar jet), before subsequently being absorbed, leading to vortex breakdown and downward wave activity flux propagation to the troposphere. Expected hashtag#Tropospheric Response: Near-term (into early hashtag#December): hashtag#Pacific: Temporary Alaskan Ridge (AkR) development; N Atlantic: Positive AO/NAO as reflected waves accelerate the jet stream—stronger westerlies and active storm track across northern EuropMedium-term (mid-late December): Increasing pattern uncertainty as absorption phase dominates. Downward coupling from the disturbed SPV likely triggers AO/NAO trend reversal. Enhanced (negative) blocking potential across Atlantic-European sector. Key hashtag#Uncertainty: The timing and magnitude of stratosphere-troposphere coupling in consecutive wave forcing events remains highly non-linear. While the ~60-day lag framework provides guidance, the volatile nature of this setup challenges deterministic forecasts beyond 2-3 weeks. hashtag#Graphics (attached): Time-height evolution of max.wave-1 height amplitude showing sustained and intense forcing in the upper and into the middle stratosphere (1-10 hPa) from late November through early December; source, incl.latest hashtag#forecast: https://lnkd.in/esD7gEtP. The persistent high-amplitude wave activity (>1500-1900 gpdm in the upper stratosphere) represents the continuous pressure on the polar vortex—key driver for the potential reflective-absorptive hashtag#SSW sequence. Additional Context: 500 hPa hashtag#GFS forecast (30 Nov) showing the main tropospheric driver: intense hashtag#Aleutian Low. Note the deep low pressure system over the North Pacific providing upward wave forcing into the stratosphere. Additional diagnostics: https://lnkd.in/eM2nHteb https://lnkd.in/eXr7cGtG