Kaylan Patel

At this time, 6-12ish hours after Erin peak, the PBL was mixing very well with the highest recorded winds occurring at the end of the dropsonde rotations when it was actually closest to the surface.

Another way to visualize sondes rotating to other quadrants in smaller eyes is on a map. You can see the normal flight path into #Erin in the "X" path while the sondes they drop along the way rotate cyclonically around the <5km pinhole eye.

It's genuinely impressive how prominent the Canadian Wildfires are this early in the season. With dozens already burning across the Canadian Shield and Interior Plains, 2025 is shaping up to become another notable season for areas that have been hit hard in recent years.

It's hard to say what the impacts are beyond just the SSTs. As it stands, the atmosphere in the region is still coupled to the prior +TNI with rising favoured in the region. That being said, moving forward as the atmosphere reacts to a more canonical cold-tilt TNI, is TBD.

In the long term this is just another complexity in the Spring Predictability Barrier moving forward. SSTs have dropped from a convective temperature (27-28C) to one that is not supportive of convection (24-25C) across the equatorial cold tongue region.

A fairly benign EWB has traversed across the Pacific over the last week and in the process was able to upwell the shallow warm pool across Nino1.2. In just a few days, the area off Peru has cooled by 2C with cooling extending into the Nino3 region.

The stratospheric polar vortex is set to weaken further in the coming days putting the 10mb u-wind near -30m/s. That value would represent the strongest reversal since the SSW of March 2016 and greatest reversal so late in the season since MERRA2 records began in the 1970s.

-Back to back days with events
-Early CI
-Rapid motions
-Dixie
-First event of the year

… The storm chasing incident page will likely begin early this year

didn't post this at 11:30 so I'm rescinding my like

TPG also denotes that there were tornadoes the Southern Plains/Dixie which aligns well with the cyclone's warm sector as it moved eastward. There's just the outlier in Northern Minnesota which doesn't align with the other factors at hand which leads me to believe it's not right.

Weather charts from Feb 22 and Feb 23 1909 show a low pressure system tracking across the Central Plains with 8am temperatures in the cold sector ranging from 10F to 20F. The warmest Moorhead (located 50 miles SW of the tornado) got over the time frame was only 28F and no precip.

I say probably because you might see that singular dot in NW Minnesota which according to Grazuli was an F2 that occurred at 2:30am on February 23rd 1909. Now I don't doubt the man but I think either the date or location is wrong for that particular tornado.

This tornado was *probably* the furthest north one was seen in either January & February east of the Rockies and in the top 5 furthest north for the month of December.

We'll have to see where exactly the rain/snow line sets up and whether it's along the QEW corridor or closer to the 407 corridor. Furthermore we'll have to see how much the high winds affect not only the SLR but also how the snow is measured on the snowboard.

The all-time snow-depth for Toronto is 67cm that was set during the winter of 1998-99. With 32cm on the ground currently and another 30-50cm on the way through this weekend, the city has a very good chance of nearing if not surpassing that total by storm's end.

Woke DEI cars has hit the ski slopes :(

Feb 2017: Predicted strong El Niño -> got La Niña instead
Feb 2020: Predicted Warm Neutral -> got La Niña
Feb 2021: Predicted Neutral -> got double dip La Niña
Feb 2022: Predicted Neutral -> got triple dip La Niña

Beyond that I'd take the output with a grain of salt due to the aforementioned Spring Predictability Barrier. There are have been a few FEB runs in the past where it's been quite far off in it's prediction compared to what actually transpired in a similar La Niña transition phase

With a growing warm pool west of the IDL and a period of weaker trade winds across the EQPAC, we should see a DKW and/or a weakening in the cold pool. This would align with the decay that the ECMWF Plumes show through the next few weeks.

The ECMWF Annual ENSO Plumes came out earlier this week and there is general consensus through the spring predictability barrier reaching neutral warm/weak ENSO+, but beyond that a whole assortment of possibilities exist as we head into the second half of 2025.

For some reason the graphic above should be a gif but it's apparently a png on Bsky :(

Why does this matter? If we do get a strato/tropo coupled SSW, the 30 days following it tend to be quite cold and snowy across North America and Europe. A strong -NAO/-AO sets up allowing for polar air to filter into the mid-latitudes for extended periods of time.

GEFS and EPS are not as excited on the prospects of a full blown SSW but agree on the PV weakening from record strong to normal levels in a few weeks time. It should be noted that they tend to have a strong vortex bias so take it with a grain of salt.

As it stands, the GFS is the most aggressive with a major SSW with a complete reversal of winds at 10mb over the North Pole. Furthermore, it shows a complete coupling of the stratosphere and troposphere suggesting that impacts would be felt at the surface.

A week later and the GFS is still holding strong on a potential PV disruption later this month. Substantial eddy flux anomalies originating across Asia will push into the Stratosphere which should weaken the Polar Vortex heading into Mid-February.

As it stands, the GFS is the most aggressive with a major SSW with a complete reversal of winds at 10mb over the North Pole. Furthermore, it shows a complete coupling of the stratosphere and troposphere suggesting that impacts would be felt at the surface.

One last thing to note is that it's impressive how the troposphere for the majority of the winter has stayed uncoupled with the stratosphere. Outside of a few week bouts, the AM in the troposphere has been consistently negative and the stratosphere consistently positive.

While nothing is imminent now, the extended range GEFS has been showing a weakening trend in the PV over the past few days. Noting the strong vortex bias, this would something to keep in mind moving forward.

I'd keep an eye on PV shenanigans as we head enter February. The GFS is showing substantial heat flux anomalies into the stratosphere during the early part of February. As a result the AM, looks to flip back negative and could couple with the troposphere later in Feb or March.

One of the goofiest snow depth maps in recent memory. Snow belts along the Gulf Coast, I-70, I-94, the two coasts and nothing in between.