The first week of October is almost in the books, and it has been a torch. The amplified pattern we've seen, with persistent ridging and high humidity for this time of year, has left both inland and shoreline locations well above normal through the first week of the month.
The story of the week however, is poised to be Tropical Storm Michael.
This is going to be a packed discussion, so grab a beverage, sit back, and let's take a look at what could be an interesting week ahead...
Tropical Storm Michael
Tropical Storm Michael has formed and is moving toward the Gulf of Mexico and the US. The guidance has continued to look bullish when it comes to intensification in the Gulf, and the National Hurricane Center (NHC) expects Michael to be a hurricane when it makes landfall.
The latest NHC forecast track is below. It's important to not just look at the points on the map. The cone shows the amount of uncertainty that exists, particularly toward the end of the week when Michael makes its closest approach to our region. 1/3 of the time, the center of a system will end up outside the cone. In addition, impacts tend to extend further away from the center point.
The steering pattern is relatively straight forward. The massive ridge that will bring us warmer than normal temperatures this week will slide east, just as a trough begins to slide east through the continental US and lift north. That will cause Michael to move northward, then NNE and northeast. The timing of the turn and speed of the system will have a significant role in what impacts, if any, Connecticut sees. Below is both the 500mb (upper level pattern) and surface depiction from the latest GFS model. I'm posting the surface depiction because I think we're close enough in time to consider this a plausible solution. This is one run of one model and other guidance has different solutions (some more impactful, some less). Take this with a grain of salt.
Usually, this kind of track would bring weak remnants, i.e., a brief period of rain with no wind. This time however, I think this bears watching for a couple of reasons.
Let's be clear. The biggest "threat", if any, would be rain. We've had significant flash flooding recently, and we've been wetter than normal in general. With an approaching tropical system, we're looking at an atmosphere that's loaded with moisture and tropical systems--even if weak--are very effective at wringing out the moisture in the air. We don't need a center passing over us to get a lot of rain quickly.
This kind of potential track could bring a period of significant rain because of the overall setup as well. It's going to be a warm week, and we're going to see a front come through just as Michael is moving northeast. If both are close enough, we could see enhanced rainfall or something known as a Predecessor Rain Event. That would bring potentially heavy rain even if the storm passes far to our south.
Of course, the other potential impact is wind and coastal flooding. However, that is highly track dependent. Instead of a weak decaying low, all of the guidance has this as a strong low that moves northeast. Much of this is because of the interaction between warm sea surface temperatures, and the baroclinic boost from the approaching through.
Overall, there's no reason to panic. Be careful of the hype that you may see on social media.
However, this is something that bears close watching, and something you will need to take seriously if we see more impactful solutions verify. A close approach would bring significant impacts, mostly in the form of rain. SCW will be tracking this closely.
The Week Ahead
The week looks warm, but there is relief in sight. We may actually go from a late summer feel to fall to a taste of winter if some of the guidance is to be believed...
Tomorrow will not feel like today. We will see a backdoor cold front push through tonight and tomorrow looks cloudy, cool, and potentially wet. We should see shower chances tomorrow, but it doesn't look like a washout. A warm front will pass through Monday night and that will bring summer's last stand.
The second day of the work week will be drier and warmer than normal, with highs for most likely ending up well into the 70s. Wednesday should be the nicest day of the work week, though it will be warm and humid. Highs may top 80 degrees again.
This is the SCW period of interest. There is significant model spread when it comes to sensible weather, but right now I think we at least see some showers and periods of heavier rain. The GFS is faster, centering any rain on Thursday, while the European model centers rain on Friday and early Saturday. We're going to have to hone this in as the week progresses. The latter part of Saturday looks better, as we begin to clear out and enjoy a fall like day. Finally.
Remember when I said taste of winter? Well, maybe that brief taste begins on Sunday. All this depends on the timing of the clearing of the front, but once the cold front passes and Michael is long gone, there will be a significant change with much cooler temperatures, particularly at night. How low can we go?
Thursday: SCW period of interest. Mostly cloudy with a chance of rain. Highs in the mid to upper 70s. Chance of rain 40%.
Friday: SCW period of interest. Mostly cloudy with a chance of rain. Highs in the upper 60s to low 70s. Chance of rain 40%.
Saturday: Mostly cloudy early with a chance of showers. Highs in the low to mid 60s. Chance of rain 20%.
Sunday: Mostly sunny and significantly cooler. Morning lows in the mid 30s (hills) to mid 40s (shore). Daytime highs in the low to mid 50s.