Location: New York
Author: Weather 2000, Inc.
Date: Wednesday, February 6, 2008
Jet Stream buckles up across East, as next Polar wave enters Midwest.........
~ Model/NWS output for several Midwest regions revised 12°F-22°F colder since yesterday....
~ Exemplifying pitfalls of mimicking/relying on models for forecast info....
On schedule, the Upper-Midwest will now embark on a 10-Day stretch very similar to the previous 10 Days, exemplified by Chicago contending with another significant snowstorm and several max temperatures failing to get above the freezing mark (including a potential single-digit max). Of course the classic "see-saw" effect is once again at work as the plunge or cold air in the Central U.S. helps buckle up mild air advection downstream (East) along with some robust thunderstorms, before they cool off as well.
Because numerical model prediction has registered such poor skill even beyond just 5 days this Winter, events like this cause any colder weather to get revised colder every half-day until a significant week is upon us. But since people's attention is continually focused "way down the road", mean-reverting models and the preoccupation with levels of the atmosphere above where we live (500, 700, 850), often paints a very benign picture that is frequently shattered by 'surprisingly' anomalous weather when these episodes are upon us.
Another stumbling block is the religious following of Ensemble Means. While ensemble techniques have been a valuable development in numerical weather prediction over the past 2 Decades, they can dilute or smooth-out the short-waves, gravity waves and IPV anomalies, which have profound impacts on volatile Winters like this year. The favoritism shown toward ensemble means can overlook the Devil in the Details, which is why true climate prediction is so much more thorough and complex than just relaying what computer models and analogs say each day.
Throughout the balance of the Winter, please remain guarded against and wary of short-term forecasters improperly attributing various climate variables to a forecast. For example, pointing to MJO (proper: Tropical Storms, Western North American Precipitation patterns, etc.) regarding Midwest/Northeast temperatures may look good on paper and make sense to a non-climate scientist, but it is overwhelmed by several other hemispheric phenomena. Before long, these forecasters will start to point explicitly to La Niņa/ENSO (proper: Hurricane Season, Tornado Season, Southwest Monsoon, etc.) for Summer temperature outlooks, and people still fall into this annual trap (even despite the negative skill these 'factors' have scored that past several years).
Such "correlations" may appear harmless, fun, be marketed with graphs, and even appear to "work. But rumor can then become belief taking you down a path of dangerous expectations. Please let us know if you'd ever like scientific clarification about a climate acronym, mechanism or hemispheric process, and we'd be happy to set the record straight.
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