We may have to deal with another intrusion of the polar vortex in just a handful of days.
Shown above is the GFS ensemble mean forecast of 500mb height anomalies over North America. We see a situation eerily similar to the one that brought about the severe cold in early January 2014. We see a Rossby Wave pushing north into eastern Alaska and Canada, as the strong positive 500mb height anomalies shows. As a result of this strong high pressure, we see a lobe of the polar vortex dropping to the south from Canada. This lobe of the vortex is illustrated well by the deep greens and low contour numbers superimposed on those deep negative height anomalies.
The GFS Ensemble 850mb level (5,000 feet level) temperature forecast for that same timeframe shows how cold conditions may get if this lobe of the polar vortex decides to scrape the United States just to our north again.
The GFS Ensemble Control 850mb temperature anomaly forecast is even stronger, with anomalies as low as -28.4 degrees Celsius in the core of the lobe of the polar vortex.
There's good reason to be concerned about a second intrusion of a lobe of the polar vortex: The Lezak Recurring Cycle supports it.
The Lezak Recurring Cycle, or LRC, is a tool developed by meteorologist Gary Lezak that, in essence, can enable forecasters to predict the overall weather pattern months in advance. The gist of the LRC involves a cycling weather pattern that develops in October and November of each year; no pattern is the same from year to year. Around mid November, the LRC begins to repeat, meaning we start to see a similar weather pattern in mid November that we saw in early October. This means that the cycling pattern has begun, and it will continue to cycle on a regular, somewhat-unchanging 40-60 day interval for the next ~10 months before it dissipates over the following summer. This season, the length of the LRC has been pegged at 57 days. If we take the January 6th date and move ahead ~57 days, we arrive in the timeframe of late February, a couple of days within the very cold weather the GFS Ensembles showed above. Considering the LRC has been an efficient tool of use in not only this winter season, but in prior winter seasons, this is likely a real threat of a lobe of the vortex coming south once again.
To sum up:
•The atmosphere looks primed for a strong cold blast in late February that will likely produce anomalously cold weather.
Andrew
Shown above is the GFS ensemble mean forecast of 500mb height anomalies over North America. We see a situation eerily similar to the one that brought about the severe cold in early January 2014. We see a Rossby Wave pushing north into eastern Alaska and Canada, as the strong positive 500mb height anomalies shows. As a result of this strong high pressure, we see a lobe of the polar vortex dropping to the south from Canada. This lobe of the vortex is illustrated well by the deep greens and low contour numbers superimposed on those deep negative height anomalies.
The GFS Ensemble 850mb level (5,000 feet level) temperature forecast for that same timeframe shows how cold conditions may get if this lobe of the polar vortex decides to scrape the United States just to our north again.
The GFS Ensemble Control 850mb temperature anomaly forecast is even stronger, with anomalies as low as -28.4 degrees Celsius in the core of the lobe of the polar vortex.
There's good reason to be concerned about a second intrusion of a lobe of the polar vortex: The Lezak Recurring Cycle supports it.
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500mb chart from January 6th |
To sum up:
•The atmosphere looks primed for a strong cold blast in late February that will likely produce anomalously cold weather.
Andrew