Good afternoon from Southern Connecticut Weather.
Tropical Storm Warning flags continue to fly along the entire coastline of southern Connecticut in anticipation of a close approach by post-tropical cyclone Hermine. At this hour, Hermine is a strong storm sitting off the US coast, packing winds of 70mph in embedded thunderstorms. Hermine is expected to strengthen more today and tomorrow, packing hurricane force winds over the Atlantic. Tropical storm force winds extend out more than 200 miles as of the latest NHC (National Hurricane Center) advisory.
Tropical Storm Warning flags continue to fly along the entire coastline of southern Connecticut in anticipation of a close approach by post-tropical cyclone Hermine. At this hour, Hermine is a strong storm sitting off the US coast, packing winds of 70mph in embedded thunderstorms. Hermine is expected to strengthen more today and tomorrow, packing hurricane force winds over the Atlantic. Tropical storm force winds extend out more than 200 miles as of the latest NHC (National Hurricane Center) advisory.
Note that the tropical storm warnings are only for the immediate coast. These are the areas most likely to experience tropical storm force winds (+39mph) over the next few days.
Above is a visible satellite loop of Hermine. You’ll notice that much of the convection (thunderstorms) are displaced well to the northeast of the well defined center of circulation. This is a telltale sign that this remains a post-tropical system. The NHC believes there is a possibility of Hermine reacquiring tropical characteristics in the next 48 hours, but this would have no meaningful impact on our sensible weather.
Right now, Hermine is moving slowly to the east-northeast, but this motion is expected to change to the north and eventually north-northwest as Hermine meanders offshore for the next few days. From there—by the end of the week—Hermine will begin moving northeast again and out to sea for good.
Right now, Hermine is moving slowly to the east-northeast, but this motion is expected to change to the north and eventually north-northwest as Hermine meanders offshore for the next few days. From there—by the end of the week—Hermine will begin moving northeast again and out to sea for good.
Connecticut Impacts
To be clear—while this is a storm to prepare for, we do not currently anticipate this being a storm on the level of either Irene or Sandy in terms of damage—especially away from the coast. First, there are no pieces of guidance showing a direct landfall in Connecticut or in our region. Those are our most impactful storms. Second, unlike some other storms, we are anticipating there being a very sharp cutoff of precipitation, which strongly limits the flooding potential away from the shoreline. Storm surge however remains a significant hazard and must be taken seriously. Let’s dive into impacts hazard by hazard.
Wind
Winds will be strong—likely reaching sustained tropical storm force along parts of the shoreline and gusts to tropical storm force are possible further inland. The latest NHC wind prediction product shows significant chances of tropical storm force winds at some point in CT over the next few days.
To be clear—while this is a storm to prepare for, we do not currently anticipate this being a storm on the level of either Irene or Sandy in terms of damage—especially away from the coast. First, there are no pieces of guidance showing a direct landfall in Connecticut or in our region. Those are our most impactful storms. Second, unlike some other storms, we are anticipating there being a very sharp cutoff of precipitation, which strongly limits the flooding potential away from the shoreline. Storm surge however remains a significant hazard and must be taken seriously. Let’s dive into impacts hazard by hazard.
Wind
Winds will be strong—likely reaching sustained tropical storm force along parts of the shoreline and gusts to tropical storm force are possible further inland. The latest NHC wind prediction product shows significant chances of tropical storm force winds at some point in CT over the next few days.
While we anticipate tropical storm force sustained winds and gusts at the shore, we expect them to be low end TS storm force. The best chance to see truly severe wind will be in eastern CT, the windy spot of the state.
Overall, wind will be strong, but nothing exceptional. I think there will be scattered power outages because of wind, but these will most likely be concentrated at the shore. If you are in an area the loses power easily, you should be prepared for that happening here.
Rain
When you think of a tropical (or post-tropical) system, you usually think about heavy flooding rains. That is unlikely to be the case here, with Hermine staying well offshore according to latest estimates.
Rain
When you think of a tropical (or post-tropical) system, you usually think about heavy flooding rains. That is unlikely to be the case here, with Hermine staying well offshore according to latest estimates.
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Above are the GFS (left) and High resolution NAM (right). That's not much rain. Rainfall is highly dependent on whether any rain bands make it far into CT, but right now we think a few will between late tonight and late Tuesday, bringing a tenth to quarter inch inland to a quarter to half inch to inch of rain along the immediate shoreline—more the further east you go. Again, this is highly dependent on where the rain actually sets up. Northwest CT and far northern CT is least likely to see rain. I currently think there will be no rainwater flooding in the state, except for maybe an isolated spot.
Storm Surge
Between rain and wind, this is likely a non-event to mild event at most for much of the state, what we do have concerns about however, is storm surge. For those at the shoreline, you should have taken steps to secure property—especially in basements and areas that are prone to flooding during events such as strong noreasters. We expect the water to begin rising as early as this afternoon, when Hermine begins to shift north. During the peak between late Sunday and early Tuesday, storm surge could rise as much as 2-4 feet in western CT, with significant beach erosion. Below is a quote from the National Weather Service on this hazard. Remember, it does not take an Irene or Sandy for storm surge to be dangerous. Take this hazard seriously.
Western and Central CT shoreline (Bridgeport/New Haven)
Storm Surge
Between rain and wind, this is likely a non-event to mild event at most for much of the state, what we do have concerns about however, is storm surge. For those at the shoreline, you should have taken steps to secure property—especially in basements and areas that are prone to flooding during events such as strong noreasters. We expect the water to begin rising as early as this afternoon, when Hermine begins to shift north. During the peak between late Sunday and early Tuesday, storm surge could rise as much as 2-4 feet in western CT, with significant beach erosion. Below is a quote from the National Weather Service on this hazard. Remember, it does not take an Irene or Sandy for storm surge to be dangerous. Take this hazard seriously.
Western and Central CT shoreline (Bridgeport/New Haven)
Eastern CT shoreline (Old Lyme/New London/Groton)
NHC PROTOTYPE Storm Surge Hazard Headlines and current NHC track.
Timing
We currently expect that conditions will deteriorate along the shore beginning very late tonight, with off and on wind/rain Monday and into early Tuesday. By Wednesday, things will clear statewide. I expect travel delays and potential cancellations at the shore, with a much reduced impact inland.
Bottom line
All in all, this is a storm to be prepared for, but nothing extraordinary unless at the immediate shore in flood prone areas. Make sure you are prepared for the prospect of power outage and flooding (at the shore) and listen to updates from your local officials.
We will be here providing updates as necessary. Please share, like and ask questions if you have them. Please send your observations (safely) on Facebook or Twitter @SouthernCTWX.
Thank you
-DB
Timing
We currently expect that conditions will deteriorate along the shore beginning very late tonight, with off and on wind/rain Monday and into early Tuesday. By Wednesday, things will clear statewide. I expect travel delays and potential cancellations at the shore, with a much reduced impact inland.
Bottom line
- Hermine will begin to turn northward and north-northwest over the next 24-48 hours, making a relatively close approach to the shoreline.
- Although currently nice outside, conditions will gradually deteriorate during late Sunday night and early Monday as Hermine make a close approach.
- Storm surge is the greatest hazard, with flooding expected to be worst along the western and central CT shore.
- There will not be a direct hit by this storm, and we expect a glancing blow with the greatest impacts being at the shoreline.
- Scattered power outages are possible, especially at the shoreline and southeast CT due to wind.
- Rainfall totals are likely to be light inland to modest at the shore. It is unlikely to be raining the entirety of any day.
- Conditions clear by Wednesday as Hermine weakens and heads out to sea.
All in all, this is a storm to be prepared for, but nothing extraordinary unless at the immediate shore in flood prone areas. Make sure you are prepared for the prospect of power outage and flooding (at the shore) and listen to updates from your local officials.
We will be here providing updates as necessary. Please share, like and ask questions if you have them. Please send your observations (safely) on Facebook or Twitter @SouthernCTWX.
Thank you
-DB
