A weak front is positioned to our south this morning with some colder air moving into the northern half of the state this morning. Temperatures in the 20s will warm into the mid to upper 40s for most locations with some 50 degree weather possible across the southern third of the state.
A weak system in the southern stream will pass the state tonight and Wednesday while the upper air flow will become entrenched from the northwest into the next few days.
Another upper level system off the southern California coastline will be ejecting into the southern plains this weekend brining increasing clouds Saturday and some rain Saturday evening into Sunday morning. The timing of this ejection will be tweaked over the next few days and would have direct impact on the amount of precipitation and the onset of some rain. EURO data would suggest some rain by Saturday afternoon while the GFS would give us some light showers late Saturday evening into the early morning of Sunday. Regardless of the timing, this system is not the focus of the forecast.
The real focus of the forecast begins this weekend into the early part of next week. Model data continues to suggest a major upper air pattern change late this week that will result in an arctic air mass developing and moving southward early next week. The initial surge will occur Monday or possibly late Sunday evening and there will be a chance of some light wintry precipitation with this first advance of the shallow cold air mass. The significant issues actually result from the lack of change in the upper air pattern next week. Data suggest a high pressure ridge near Alaska with an upper level low over western or central Canada. This will effectively keep the arctic air entrenched and even augmented through much of next week. The hints in the model data are displaying a McFarland signature which is many times present with the onset of a serious surge of bitter arctic air. This signature suggests the air mass may travel well south into Texas or the Deep South with the central and especially the northern high plains in store for extremely cold air by the middle of next week.
January is typically the coldest month of the year from a climate stand point and the expected pattern next week will offer the potential for an extended period of temperatures below freezing.