Our beautiful work week is going to turn into a wet, raw, and breezy weekend as a tropical disturbance off the southeast coast is poised to develop and move northward. Let's dive in.
This setup is pretty straightforward. We commonly see subtropical or tropical systems develop this time of year off of decaying boundaries off the southeast coast, and that's what's happening here. A broad area of low pressure is currently non-tropical off the southeast coast, and is expected to consolidate some and intensify.
Frequently, we see these systems go harmlessly eastward and out to sea, but this time, we have an Atlantic ridge that will strengthen and steer this low northward to north-northwestward. As that happens, a strong high pressure will develop to our north, blocking it from going out to sea until it gets close to our latitude and a weakness between the two ridges develops.
The general track guidance is now a high confidence forecast, and the GFS depiction below shows this steering pattern well.
Tomorrow looks like another great day. The low pressure is likely to become a tropical storm as it heads north into North Carolina. The next name on the list is Ophelia.
Future Ophelia is likely to take a track that allows for tropical moisture to push into CT on Saturday. Unfortunately, even the morning hours are now looking wet, as moisture from the storm pushes into the state from south to north around 7am. One thing to watch is the push of heavy rain. The guidance for the most part has kept the heaviest rain offshore on Saturday, which reduces flooding risk. However, we need to see if this changes over the next few days as a boundary could set itself up somewhere south of CT allowing for more efficient (read: heavier) rainfall.
Here's the GFS depiction of that push of moisture on Saturday. It looks like a rainy, raw, and windy day, far more than what we saw with Lee. There may be some minor coastal flooding with a persistent onshore flow, and that's something we'll be watching.
Winds could be on the order of 25-35mph, maybe a little higher at the immediate shoreline, as a gradient between the strong low to the south and high pressure to the north clash.
That's not the end of the rain, however. While there may be a break late Saturday into early Sunday, the remnants of Ophelia will turn northeast, putting the remnant low below CT most likely. As this happens, the rain may be enhanced near the center, meaning that Sunday may be even worse than Saturday even as the wind diminishes. The timing is still uncertain, but heavy rain is possible Sunday into early Monday.
Once again, the GFS (and other guidance) depicts something similar.
What is likely to become Ophelia is likely to bring a washout weekend. I do not anticipate significant power outages or coastal flooding issues. It won't rain heavy all the time, but between Saturday morning and early Monday morning we could see 1-3+ inches of rain. Considering that most of the state has already seen well above normal precipitation for the month of September, and the summer overall, we have to watch for flooding if the wetter solutions play out. As a reminder, the entire month of September usually sees around 4" of rain.
This is likely to play out like another very wet nor'easter.
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