Tuesday, August 04, 2020

Hurricane Isaias: August 3, Update A

Congratulations to Bob and Doug who made Earthfall yesterday afternoon in the Gulf of Mexico! (see end of this post for more on Bob and Doug). 

But the story for today is Hurricane Isaias, who made Landfall at around 11.10pm in southern North Carolina, near Ocean Isle Beach. 

He was doing really well today, fluctuating between a strong and very strong Tropical Storm/almost cat 1, but in the last few hours he did jump the hurdle into the cat 1 hurricane bucket (that's what happens if you put buckets on the other side of hurdles ;-)). Maximum winds at landfall were 85mph, which makes him officially a mid-range cat 1 storm (central pressure 988mb). I'll go with the NHC on this, although I'm not sure he was quite that strong. He started to fall apart just before landfall and you can clearly see his center as it moves over North Carolina in the infrared satellite imagery: 

However, there is some vorticity (circulation) in the upper troposphere, so I would definitely place him as a cat 1 with winds of at least 75mph. He'll continue to weaken as he moves over land. 

This satellite image also shows that his convection has decreased quite substantially since even this morning. As I said, he was getting a lot of that rain from the warm Gulf Stream waters he passed over, so as he moves farther inland, this will also continue to decrease. As a reminder in interpreting this sort of satellite image: the gray areas are just clouds, the blue are drizzle/light rain, the green is heavier rain, yellow is quite a bit of a downpour, and orange/red is torrential rain with thundery stuff and possibly a tornado. 

He is currently at 33.9N, 78.4W, heading NNE at a rapid 22mph and is forecast to continue inland from here on out: 

He's also moving a lot faster now compared to the past few days and will cover a LOT of ground over the next 2 days (which means he'll be through your area quite quickly of course). That's because he's getting caught up by the jet stream (a boundary of strong winds between warm and cold air in the upper levels of the troposphere), which will give him some energy from the atmosphere (instead of gaining energy from warm water below). He'll have a lot of forward speed, even though his intensity will decrease - but the combination of the two will make him stay a little windier as he moves up the coast. 

As for storm surge, it looks like water levels are around 2 ft above mean sea level in Wrightsville Beach and along the coast (from the tidesandcurrents website). 

A quick note on the Atlantic Blobette that's hanging out around 26N, 66W - I see you! There's some vorticity in the lower half of the troposphere in this system, so the structure is there, but there isn't any convection really. The NHC give her a 40% chance of developing in the next 48 hours. Next name would be Josephine.

And a final word about Bob and Doug...

Can you believe these guys just returned from space? I hope they figured out the answer to the beer question. 

More tomorrow my maybe-soggy friends!

Twitter: jyovianstorm
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 

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