Alexander Renășteanu

Citizen Scientist (22) | Author of SDI-BI-CI-EI Suite | Scienza libera: la conoscenza non ha prezzo

[Giuseppe Petricca @gmrpetricca]

The 10 hPa zonal mean wind at 60°N, having briefly touched 0 m/s on Nov. 6th, has now properly reversed into easterly flow over the past few days.

As mentioned in previous updates, this is the earliest such reversal on record. Previously, the earliest occurrences were during the 1968/69 and 2025/26 winters, both on Nov. 28th.

Models are still struggling to resolve this unprecedented evolution and its interaction with the tropospheric circulation, so significant run-to-run changes are to be expected. It will certainly be interesting to follow!

Looking at the recovery, the vortex at 10 hPa is forecast to return towards seasonal-average strength. GFS and GEFS show a faster recovery, while ECMWF and AIFS are more conservative.

However, the multi-level charts suggest that weaker-than-normal winds could persist lower down in the stratosphere. This is consistent with the signals in the zonal GPH charts, where some downward progression of the anomalies and potentially renewed stratosphere-troposphere coupling remains possible.

[AllNature @PvForecast]

AAM is astuning #winter #denniswinterindex

[Alexander Renășteanu @AlexWeather25]

@PvForecast I’ve spotted an interesting situation that bears watching very closely.

[AllNature @PvForecast]

some is ahead to PV again Wave 2 #denniswinterindex

[MetRyan @MetRyan96]

Fuck it, cant be calm anywhere it doesn't work. WIDEPREAD HEAVY FUCKNI TWATTING SNOW SHOWERS (also organised bands of snow) WANKING IN FROM THE EAST. ACCUMULATIONS EASY OVER A FOOT FROM THIS RUN EASY

[Alexander Renășteanu @AlexWeather25]

@PvForecast @judah47 @Superchri90 @Recretos

[Alexander Renășteanu @AlexWeather25]

With the help of AI, I’ve managed to reconstruct the QBO situation... and, let me tell you, it looks like we might be heading toward a scenario similar to 2016 only earlier than it unfolded that year. We’re talking about a potential QBO disruption
#ElNiño
#PolarVortex
#Winter

[AllNature @PvForecast]

Zonal #polarvortex wave2 #denniswinterindex

[UK Weather Updates @UKWX_]

We are in SSW territory, marking this the earliest SSW on record. The impacts of the SSW are likely to flow down to surface over the next few weeks increasing the risk of blocking episodes going into December, aided by other tropospheric influences.

[AllNature @PvForecast]

Gfs 6z #WINTER

[Alexander Renășteanu @AlexWeather25]

@judah47 @Superchri90 @PvForecast @Recretos

[Paweł Huryn @PawelHuryn]

Many people have wondered why they couldn't access Gemini 4 Carbon on Google AI Pro. Here's a reference card.

(yes, disappointing, you have to upgrade or use the API)

[PyRe Weather @pyreweather]

BOOM! Here it is!! That little green wedge on the right side of the lower image? that's the easterly turn of the 10mb winds at 60N Latitude.

The Sudden Stratospheric Warming event has officially arrived!!
@Statisticizer

[Judah Cohen @judah47]

Did someone order Turkey on ice? The models are in agreement on a an interesting pattern for Thanksgiving that is favorable for an East Coast snowstorm. I admit more what if than a real risk for now but I'd be excited to this pattern in a month! Consistent with influence of #SSW

[Judah Cohen @judah47]

@HamoudaMosti & I computed the patterns of October Eurasian #snow cover extent. The dominant one is a continent wide snow cover that is increasing. The second is a dipole with more snow in East Asia but less snow in West Asia, that is getting stronger with 2026 the highest value.

[Alexander Renășteanu @AlexWeather25]

@judah47 @Recretos @Superchri90 @PvForecast

[Alexander Renășteanu @AlexWeather25]

Since October 1st, I have been collecting data on Eurasian snow cover using NOAA IMS satellite data. I will update these charts every Thursday.
#Winter
#Snow
#ElNiño
#PolarVortex
#weatherforecast

[Alexander Renășteanu @AlexWeather25]

@MUweather @epawawx It was, therefore, a unique event, so we cannot use it as a point of reference for what we are experiencing now.

[Alexander Renășteanu @AlexWeather25]

@MUweather @epawawx I understand perfectly; however, based on what I’ve read in published studies on the subject, it appears to have been a hybrid one that, in terms of its circulation patterns, was almost a Modoki type

[Met4Cast - UK Weather @Met4CastUK]

There is a growing signal within model outputs that today’s major SSW will “drip” down into the troposphere later this month and into early December.

This, coupled with favourable troposphere teleconnections will increase the likelihood of high latitude blocking and outbreaks of cold weather during early December.