Oklahoma needed moisture badly to stymie raging grass fires. After setting record highs on Sunday, much of Oklahoma got some needed moisture late Monday and Tuesday -- in the form of snow.

While welcome, the 1-4 inches of snow that fell on central and western Oklahoma is not remotely close to a drought-breaker for them, nor is it anything resembling a wholesale return to winter over the continental United States.

The jet stream is continuing to roar from west to east out of the Pacific, continually reinforcing the mild Pacific air we've been experiencing while keeping the Arctic air bottled up in Canada. There's nothing in the northern Atlantic to block this flow, as would happen in a cold period like in December.

While this pattern probably will change with time, maybe in late January or February, to bring more winterlike weather back to the states, the drought over the Southern Plains is something to be concerned about for its longer-term importance.

Drought has a way of perpetuating itself. A long period of below-average rains dries out the soil, and this in turn leads to having less moisture to evaporate into the air immediately above the surface.

As a result of the dry air above the surface, weaker rain systems that would normally bring showers have their rain evaporated in the dry air before reaching the surface. This in turn leads to areas east of the drought region seeing less precipitation, and the drought can expand with time.

The Dust Bowl of the 1930s occurred something like this, beginning in the Southern Plains and spreading out to affect many areas of the country.

Some areas of Texas, Oklahoma and Arkansas are running 20-30 inches below normal in precipitation for the past year. It will take more than a few dinky showers or light snowfalls to break that kind of drought. And should it persist into the warm months, this area could become a center for unseasonably hot weather that could spread eastward and northward and result in hot, dry weather in other areas of the country.

We all know that droughts can be broken. What it requires, though, is a fundamental change in the overall weather pattern to absolutely flood a drought area with a vein of moisture from a warm ocean region.

Often in winter, a train of storm systems comes across southern California or northern Mexico across the southern United States, the Gulf of Mexico region, and then either heads out to sea or up the Eastern Seaboard. This southern branch of the jet stream has been almost nonexistent this winter.

So, as we watch the weather pattern to see if it will eventually bring winter back to our area, we'll also examine whether or not it can restore some moisture to the Southern Plains. If not, a mild winter for much of the country may run on into a warm, dry spring, and a hot, dry summer.

A few notes

n In Saturday's column, I wrote of our area being overdue for a major snowstorm. To clarify, I meant that we have gone longer between foot-plus snows than we typically do, statistically. The fact that we have not had a big snowstorm does not increase or decrease the likelihood that we'll have one soon, just as the fact that we had a 100-year flood in 1985 does not increase or decrease the likelihood that we'll have one of those soon.

n Some of you have e-mailed or called about the weather chart on the back of the Virginia section showing the same sunrise time (7:34 a.m.) for several days in a row. We've checked, and this is actually correct: The sunrise time changes by only a few seconds for several days in January. Why? I'll have to ask someone with more of an astronomical bent.

n The Virginia Tech Seismological Observatory recorded a seismic event at the Sago Mine in West Virginia on Jan. 2 that correlates closely with detection of a lightning strike by Weatherbug's lightning network. This comes from a news release from Weatherbug and also the Virginia Tech Web site. The parties involved in this finding stress that this does not conclusively prove that lightning caused the blast that killed 12 miners, but this information is being provided to investigators seeking the cause of the mine accident.