Indecision 2008: Southern Plains Edition

If you don't like the weather in Oklahoma, wait five minutes and it'll change. That old saying has been particularly true during the last week of January, during which time Oklahoma has experienced unseasonably warm 70 degree weather, frigid lows dipping into the single digits, south winds gusting to 50 miles per hour, north winds gusting to 40 miles per hour, red flag warnings, wildfires, freezing rain, sleet, and in areas, upwards of six inches of snow with drifts of up to two feet in depth expected. So, just what has been causing this meteorological roller-coaster ride? Sit back, relax, keep reading, and we'll reveal the culprits.

The most obvious culprit has been a series of fast-moving storm systems tracking across the plains, keeping our winds and our weather in a constant state of flux. A visible satellite image of one of these storms is shown above - you can see a line of convection over the gulf that extends into central Louisiana, a large deck of stratiform clouds associated with rain and snowfall from Oklahoma through Kansas, Arkansas, Missouri, and extending north and east beyond the edge of the image into Illinois. Key to the constantly shifting weather pattern has been the fast motion of the storm systems and a lack of cold, arctic air to move in behind the system and reinforce the cold advection brought in its wake. Without arctic reinforcement, southerly return flow has been allowed to re-establish itself after the passage of each storm system, resulting in strong warm advection and gusty southerly winds. In fact, in the five days between Jan. 27 and Jan. 31, the dominant wind direction in central Oklahoma has shifted each day, from northerly, to southerly, to northerly, back to southerly, and finally back to northerly once again.

These shifting, gusty winds have not only brought alternating shots of warmth and cold, but also the return of another danger: wildfires. It might seem somewhat counterintuitive that we'd be facing wildfires after just recording the wettest year on record over much of Oklahoma (in Oklahoma city the annual record was utterly demolished as 2007 posted a rainfall total five inches above the previous all-time high). However, much of that rainfall came during the spring and summer months, leading to an abundance of lush, green vegetation. In the fall and winter that followed, we actually experienced drier than normal conditions, allowing all this lush vegetation to dry out and die, creating an abundant supply of fuel for wildfires. Add to that the results of December's impressive ice storm - branches and debris still yet to be cleaned up and removed - still more fuel for the flames. Gusty winds, low humidity, and warm conditions during portions of the final week of January led to red flag (fire weather) warnings, and several fires in southern, southwestern, and central Oklahoma, including small fires within the Oklahoma City metro area.

From fire, let's move on to ice. The frontal system pictured above brought late-January snowfall to much of central and northern Oklahoma. Up to seven inches fell over parts of northern Oklahoma, and strong northwesterly winds behind the cold front whipped up blowing snow and near-whiteout conditions. Snowfall in January is not uncommon - Oklahoma City averages around 3 inches of snowfall during the month of January. Average highs in central Oklahoma for the last week of January are in the upper 40's, and large departures, both above and below average, are also quite common.

Looking forward into early February, a pattern of zonal flow (characterized by a lack of strong ridges and troughs) is predicted to develop, bringing hope for a respite from the wildly changing weather patterns of late January, at least for a few days. The beginning of February will also bring the annual appearance of one of the nation's most famous forecasters: Punxsutawney Phil the Groundhog. As of January 31, the Groundhog Day forecast for Phil's locale is cloudy with a chance of snow - and a distinct lack of shadows.

For more information on (and photos of) the December 2007 ice storm, check out this summary by the Tulsa NWS forecast office .

For more information on local weather and climate, visit the Oklahoma Climatological Survey.
For more information on Oklahoma weather, we recommend the following local links:

• Significant Weather Events from the National Weather Service office in Norman
• Climate Event Summaries from the Oklahoma Climatological Survey

Story is © Nate Snook, 2008