Hopefully everyone has been enjoying a week of unseasonably mild temperatures and even record warmth in the Southern Appalachian region this week, because we have changes ahead of us, and quite a few them at that. Let’s get started:
Tracking Remnants Of Nicole:
Nicole, once a hurricane, has now weakened to a depression and is currently located over the Florida/Georgia border as of around midnight eastern daylight time. The storm will track northeast along the spine of the Appalachians with heavy rainfall and scattered lines of severe storms over the Carolinas and Virginia overnight tonight into Friday. The parameters are actually quite concerning for tornado activity from rotating cells over these areas and the Storm Prediction Center has outlined those areas accordingly. Be cautious if traveling into these areas today east of the Appalachians.
Meanwhile, the Tri-Cities should not experience any tornado activity, but winds may gust in excess of 30 mph in the lower elevations with higher gusts possible in the mountains where wind advisories are in effect. Moderate to heavy rainfall will be likely at times in East Tennessee through Friday evening. As much as 1-2 inches may fall in some areas; a welcome addition to many areas close to our southwest who have been grappling with drought conditions in recent months. Temperatures are still fairly mild for your Friday with highs expected to reach into the mid upper 60s for many areas before changes arrive later this weekend. The unseasonably warm weather is ending; probably for a considerable stretch of time.
Turning Colder This Weekend:
November For This Weekend
Map Courtesy: Tropical Tidbits
If you’ve been following us this month, you know we’ve been talking about this pattern change for upwards of a week now. On November 2nd, we talked about the unseasonably warm pattern that would likely bring 80° heat to the Tri-Cities , followed by a late season tropical system impacting us later this week, and then a change in the pattern by this weekend. Everything is in fact going according to planned. Looking at the current GEFS jet stream pattern, we find things are very similar to what the ensemble forecast showed as much as 9 days ago. You still have a ridge over the Eastern US, but it’s beginning to be penetrated by Nicole moving in from the south, and a trough incoming from the west as the ridge begins to build. Western ridging will bring a noticeably and predominantly colder pattern to the Eastern US for the next week to 10 days at least, including the Tri-Cities.
Map courtesy: Tropical Tidbits
Behind Nicole, another disturbance on the front of the trough in tandem with a cold front, will bring about more rain showers on Saturday as temperatures gradually begin to fall. Colder air just to our west will catch up with the backside of moisture allowing for a swath of wet snow over portions of western and middle Tennessee into the Ohio Valley where light accumulation may occur.
Our area will see highs in the 50s Saturday and will not see temperatures fall sufficiently enough to allow for frozen precipitation until Saturday night. At that point, moisture will be very limited, but northwest flow may allow for a few flurries into early Sunday in spots, with no appreciable accumulation anticipated. Lows Saturday night will drop into the upper 20s and lower 30s, and Sunday will only climb into the 40s at best; a dramatic shift from last Sunday’s June standards.
Cold And Active Next Week:
What is allowing our pattern to turn colder? For that answer we are looking at something known as the East Pacific Oscillation, or (EPO). The East Pacific Oscillation refers to the jet stream pattern over the North Pacific. When it is in its negative phase, it allows a ridge of high pressure to form over the North Pacific and Alaska; effectively cutting off much of the mild air flow from the Pacific into North America and begins to encourage colder air over Siberia and the North Pole regions to charge south in what is termed “cross polar flow”.
This can lead to anomalously cold temperatures in much of North America, including the United States. The EPO is expected to be deeply negative over the next week to ten days at least; strongly encouraging that idea. This will allow temperatures to be predominantly colder than normal in the Eastern US; including our region, and with an active storm track we may see some opportunities for frozen precipitation.
Given it is still November, it’s a little early in the season for winter weather chances to be overly high and there are some limitations. Nevertheless, we are tracking multiple systems next week that may at least offer up the chance for some wet snow or wintry mix with periods of cold rainfall. Stay tuned for more in depth updates on that in the next few days as our forecast models consolidate more precisely.
Thank you for following with us as we track changeable conditions heading into the winter!
– StormTrackerSacker
Assistant Forecaster TWAC2