Good Tuesday Evening. A wet weather day lingers into the night. The HRRR model did well predicting this weather event. Rainfall totals of 5-8 inches were common across the southern and eastern-facing slopes. Away from the mountains, generally 2-4 inches of rain fell. Light rain and drizzle will continue into the night.
After a Wednesday Morning with fog and drizzle, look for clearing to be slow. The rain will come to an end finally, though. Dry weather moves in for Wednesday Night before an upper-level low-pressure system brings colder weather. Snow will develop in the Mountains Thursday Night and last into Saturday. Snow may break containment of the mountains Friday into Friday Night. Behind the upper low, we will dry out late Saturday into Sunday before another low-pressure system threatens our area on New Year’s Day.
The flash flood watch has ended across Polk and Rutherford Counties. Still, the watch will remain in effect through Wednesday Morning for the I-40 Corridor, which continues to include Cleveland and Lincoln Counties. The back end of the rain has stopped its eastward progression early tonight, but it should start moving east as we move past the midnight hour.
The rainfall is light enough across the western foothills now that it should let the streams and creeks crest and then slowly recede. There continue to be some embedded torrential downpours with cells moving north through Cleveland, Lincoln, Catawba, Alexander, and Gaston. These areas of heavier rain should continue to weaken as the most significant lift shifts East of the region early Wednesday Morning.
High pressure will begin to build on Wednesday, drying the atmosphere out. With overnight lows struggling to drop out of the 50s tonight, the stage is set for another warm Wednesday. Highs will likely top out in the mid-60s across the foothills. Even the mountains could get close to 60°.
The upper-level low-pressure energy is now cut off from the northern jet stream and is situated right over the middle of the country. That low will begin to drop South and East Wednesday Afternoon, reaching the mountains Thursday Night into Friday and the foothills Friday into Friday Night. Even so, temperatures will still return to the mid-50s Thursday. The area becomes under the influence of that upper low Friday, impacting the area’s high temperatures a bit more.
Friday highs will be in the low to mid-40s. As the upper low moves from middle Tennessee southeast to the southern Appalachians Friday, temps in the mountains will support snow showers. Depending on the timing of the best dynamics East of the mountains across the foothills, I think a mix of rain and snow showers will be possible. If, and a big if, a deformation band of precipitation can develop as a surface low grows along the coast, a period of light snow is possible even across the I-40 corridor. I wouldn’t expect any accumulation as surface temps will most likely remain above freezing until midnight Friday Night and Saturday Morning. I don’t see any scenario where heavy snow develops outside the mountains to effectively dynamically cool the atmosphere from the top down because the surface low will be lifting up the coast quickly and out to sea. Any surfaces that do get wet will freeze after midnight into Saturday Morning as lows reach the mid and upper 20s.
Saturday Afternoon and Sunday should be quiet across the area as high pressure builds into the area. Expect highs to remain in the 40s all weekend with mostly sunny conditions.
The pattern continues to be active across the southeast, though, going into next week. Another upper-level low and clipper-type system will likely impact the area on New Year’s Day. This energy will bring the next shot of a brief wintery mix Monday outside the mountains. Right now, models are in significant disagreement as to the amount of moisture that moves North ahead of the upper-level feature. The GFS activates the southern jet and brings more moisture into the area, falling as mainly a rain/snow mix. The EURO does not see the southern jet as being in a playful mood and in turn, is mute on any precipitation outside of mountain northwest flow.
Next week, the pattern looks to remain cool, with yet another system potentially impacting our area late next week. A low-pressure system could develop in the southern stream around the Gulf of Mexico and then move up the east coast. It is to be determined as to how strong or what track this system will make. This system would be in a Thursday to Friday timeframe next week, so there is plenty of time to watch it. What gets me a little more excited about that system on January 4th and 5th is that it has decent ensemble support, something we haven’t seen in a long time. So, let’s keep an eye on it.