Monday, December 19, 2005

Ridge, "I'll be Back (Week 2?)"

Current weather-climate situation is nothing short of a "non-linear mess", and where the atmosphere is going after days 5-7 is about as unclear as it gets! While the main area of tropical convective forcing remains stationary at around 110-120E near the equator, yet another second region is at about 160E. Meanwhile, the north Pacific jet has evolved into a deep trough at roughly 150W, with 250mb wind speed anomalies on the order of 50 m/s.

We think the impacts of the seasonal cycle may be starting, with some evidence of the convection starting to move into the southern hemisphere. Will this shift reset the atmosphere like what happens when you reboot a computer? Perhaps two reasonable possibilities exist: (1) the convection suddenly shifts east (and south), and the north Pacific jet remains extended and stronger than average, or (2) forcing remains generally across the eastern hemisphere and we get more eastern Pacific/west coast anomalous ridges. While (1) is in the process of occurring for week 1 (through Christmas weekend), the scales of atmospheric balance may tilt slightly to (2) as we go into weeks 2-3 (December 26-January 9). Indeed, some of the global ensembles such as the 1200 UTC 19 Dec NCEP GFS start to rebuild the ridge strongly starting early next week. We think this situation needs to be monitored very closely.

Folks in southwest Kansas can expect dry and warmer weather through Christmas weekend. Most of the snow should melt during the next few days. From the period of December 23-26 maximum temperatures may reach well into the 60s and lower 70s. Cooler and wetter conditions may return to southwest Kansas during the first week in 2006.

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