Joe’s Weather Blog: A multi part storm in Florence (TUE-9/11)

Hurricane Florence continues to move towards the Carolinas…and the data hasn’t wavered much over the past 5 days or so…it’s been somewhat amazingly consistent (except the GFS model) and that’s why you’re hearing more confident forecasts and have for the last few days. There are still obvious landfall issues and while many focus purely on that part of Florence, in reality, it’s a small part of what waits for that part of the country. For example…many remember the devastating flooding in the Houston area from Harvey…but landfall on that terrible hurricane was actually much farther south…north of Corpus Christi…it was the stalling part of the storm and the looping back into the Gulf that created the devastating floods that were the main component of the storm.

Florence has now become the biggest news story of the day and you’re hearing a lot about preparations…over 1 million being evacuated, perhaps more. Storm surge…wind…tornadoes…coastal erosion, and what may be the biggest issue..inland flooding…are all likely unless something different happens in a substantial way compared to the data available.

Models this morning are showing the tell tale signs of either a slowing hurricane or a hurricane that tries to do loop de loops (sp) as the storm comes inland…this is a result of a collapse of steering. Also sometimes as hurricanes come ashore the frictional effects of land can slow the storm down…especially when there is not a lot of push to the storm to begin with.

More of Florence in a minute.

Back home into KC though…status quo…nice weather with warmer temperatures through the weekend…highs may nudge close to 90° in some spots, especially downtown KC. No rain is expected till early next week and I’m not confident we’ll get that much from that although we should see a nice cold front come through the region.



Forecast:

Today: Sunny and seasonable with higher into the lower 80s

Tonight: Clear and pleasant with lows near 60°

Wednesday: Sunny with highs 80-85°

Thursday: Sunny with highs in the mid 80s



Discussion:

Obviously let’s get more into Florence.

When hurricanes intensify rapidly, like what happened yesterday, in many cases they peak out and actually weaken a bit. This is because the core of the storm undergoes a restructuring. This is called an ERC or Eyewall Replacement Cycle. This occurred last night. What happens is that the eye of the storm falls apart as a new eye surrounds it and eventually replaces it. Instead of a nice clear center of a hurricane on the satellite pictures…the eye gets more disorganized and isn’t circular anymore. As this process occurs the winds around the core of the storm tend to weaken.

This happened as well…the morning update has Florence “down” to 130 MPH…

Interestingly though…as this process occurs the wind field of the hurricane actually expands…so the hurricane actually becomes bigger in size. Winds expand away from the core of the storm…the waves increase farther away from the center as a result…and in the end you have a bigger hurricane in size at least.

When the cycle completes…assuming the atmosphere is still favorable and the Ocean is still warm (that’s the gas for the hurricane engine) the storm can get stronger again from a wind perspective and model data this morning shows this potential today and tomorrow.

As the day moves along and you watch the images looping above…note the eye of the hurricane…IF it starts to clear out again…that will be a sign that the storm is strengthening from a core standpoint. There is recon data this morning that is showing perhaps a new strengthening process is beginning

What happens at flight level (close to 10,000 feet or so I think) isn’t necessarily what happens on the surface…but it can be an eventual indicator down the road.

Messaging of the storm though hasn’t changed really. Again while the landfall point may change the results will be about the same.

The winds from Florence will really start increasing later Wednesday into Thursday morning.

All the graphics above will be updating throughout the day and night so the most current information will be on the blog.

When many talk about hurricanes…the winds are always the 1st item of conversation…how strong are the winds? That seems to be the measure of hurricanes…which gets you half way down the road really when it comes to landfall. In the end though, as I showed you yesterday…flooding is almost the bigger issue and with Florence that will likely be the main thing again.

From a wind standpoint…lots of damage will take place near and to the right of the core’s landfall along the coastal areas.

The chart above, via the EURO model shows the cumulative wind swath of the storm into the weekend.

Look carefully below…the EURO model portrays the strongest wind gusts in the Carolinas. I saw a 120 MPH gust and odds are there are stronger winds somewhere near the core. These would be the strongest winds later Thursday as the storm comes ashore

From the NWS in NC…

Then data suggests that the storm will stall. Flooding is going to be the main problem then.

The map above is VERY subject to change…and the axis of heaviest rains/flooding will be changing I think over the next couple of days as we try to figure out where the stall occurs and what happens from there.

As you might expect…while we may think that the Carolinas are used to this…it’s not that often that this strong a hurricane hits.

Note the height of the water from 1954 and Hurricane Hazel…another 5 FEET higher than the devastating floods/water levels from the other storms at Wrightsville Beach.

Are folks in NC prepared…well yes and no…

A LOT of people don’t have the proper insurance…so that aspect isn’t encouraging. Flood insurance is VERY expensive and many simply can’t afford it.

Then there is the aspect of new people moving there…and this is a BIG issue as well. The last major (110+ MPH winds) hurricane to hit the Carolinas was HUGO back in 1989…that’s almost 30 years ago! Many haven’t gone through a hurricane like that before.

For example…in Wilmington, NC…in the mid 80s there were about 45,000 people living there…since then the population has more than doubled to close to 120,000. A LOT of folks don’t have a memory of a storm to fall back on…and say to themselves “we want no part of that again”. You can really appreciate this by looking towards the coastal areas especially…and this is since the year 2000!

Since Hugo…it’s even more apparent courtesy @SteveBowenwx

 

 

 

 

 

 

 

 

 

The land use has changed as well over the decades. I sent this tweet out yesterday showing the changes since the mid 80s in Wilmington, NC.

So there are many aspects to this eventual disaster at play right now. From storm surge (more on that tomorrow) to wind damage along the coastal areas…to flooding…and other items to consider with this storm.

It is an impressive storm!

There is some consternation within the weather community about the seemingly poor forecasts coming out of the GFS model. It remains to be seen what eventually happens with Florence but in most cases the GFS model has been ignored by most seasoned forecasters because is some strange solutions. The GFS model is likely to be replaced to start 2019 by a model called the FV3…which has been more consistent and seemingly more realistic with it’s portrayal of intensity etc with this storm. One meteorologist took a deeper dive into WHY the GFS model may be performing poorly with it’s forecast. I even learned something and it all comes down to microphysics.

OK I need to stop here…if you can find a more thorough and comprehensive blog about this storm…let me know I need to check it out!

Our feature photo comes from Tammi Camlin…

Joe

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1 Comment

  • Richard

    Thorough and comprehensive to the max Joe !
    Really appreciate all of these blogs about this monster.
    Very extensive data and info. A lot of thought and work went into them.
    I learned a lot. Thank you