Saturday, October 7, 2017

Is Hurricane Nate A Hurricane?

Trick question?  Nope.  Bear with me.

From the 8PM EDT Statement:
LOCATION...29.0N 89.2W
Winds 85 mph, forward movement North, or 350 degrees, at 20 mph.   Around the time of Irma, last month, I learned that the winds are reported, the forward motion is already taken into account. It raises the question of just what the winds in Nate really are.
In general, the strongest winds in a hurricane are found on the right side of the storm because the motion of the hurricane also contributes to its swirling winds. A hurricane with a 90 mph [145 km/hr] winds while stationary would have winds up to 100 mph [160 km/hr] on the right side and only 80 mph [130 km/hr] on the left side if it began moving (any direction) at 10 mph [16 km/hr].

Note that forecasting center advisories already take this asymmetry into account and, in this case, would state that the highest winds were 100 mph [160 km/hr]. [Note: emphasis in original - SiG]
Consider the geometry they describe:
In this case, the red arrow is pointing north.  The winds on the right (east) side of the storm are reported at 85 mph and that includes the 20 mph forward motion.  That means the winds on the north side of the eye where the forward motion contributes nothing are 65 mph, 10 mph below Hurricane strength, and the winds on the west side of the storm are (WindReported - 2 x (forward speed))  or 45 mph.  That's the weakest wind defined as a tropical storm.  The winds along the south side of the eyewall, where forward motion again contributes nothing to the speed, are 65 mph again.   Stripped of the effects from forward motion, it becomes a tropical storm with 65 mph winds everywhere.

There is only one area in Nate that's a hurricane force storm and that's a small area in the eyewall on the east side of the storm.   Normalized to 10 meters (33 feet) elevation. 

Why does this matter?  Follow the money.  Far more geographical area is going to be affected by Nate than will experience hurricane force winds.  Because this is called a hurricane, it will invoke the higher deductibles homeowner's insurance charges for hurricanes.  That's typically a much higher deductible than if this was treated like a thunderstorm, which can easily generate winds that will be seen in most of Nate.  I honestly don't think Nate should be called a hurricane.  If the 85 mph winds were on the north and south sides of the eye wall, and the east side became 105 because of forward motion, that seems more like a hurricane than a storm with a tiny area that reaches 85 because of the geometry of its path.  Which means the NHC would have to describe the winds as if the storm weren't moving. 


  1. Watch the reported surface winds tonight. Not much so far.
    Is there any part of out government that doesn't lie to us?

    1. Rampant speculation department. After Andrew the insurance companies in Florida said they almost went bankrupt because the expenses were so much higher than what was planned for. IIRC, it was the first major hurricane in Florida in a long time and they were unprepared.

      So the state did a lot to convince insurance companies to stay. I'm wondering if part of the compromise was to get the higher deductibles and get the NHC to make the forecasts include more minor storms. Maybe also make them hype storms more than they were doing then.

    2. If they actually reported storm strength in the manner you request, just HOW MUCH do you think your homeowner's insurance would cost? If you could even get any, that is. I insure with USAA. I am eligible because of my time in the Air Force. My rates are better than what you're paying, but not massively so. USAA is an insurance cooperative. As an insured, I am a part owner. They don't make a profit. And also their insured tend to be somewhat more honest than many in the general population. Yet they STILL charge in the same general area as the rest of the industry. In this case, Our Betters are really looking out for the Mere Citizens. The only thing they could do better would be to let the insurers charge the Beach Bunnies a valid cost for THEIR insurance. But that ain't gonna happen for two reasons:

      1. Beach Bunnies tend to be major donors to political campaigns - follow the money.

      2. Media High Rollers tend to like being Beach Bunnies. If politicians dared to let the insurers charge Beach Bunnies with insurance rates appropriate to the risk, the Media would have something more important than Donald Trump to feature on their "news".

    3. "Nonprofit" can be a bit misleading. The company may be non-profit, but the people who run it certainly make large bundles of cash.
      Orlando Health, a non-profit that runs a chain of hospitals in central Florida, pays its COO more than $1.5 million a year.

      The Clinton's non-profit company is funneling millions into the Clintons' pockets.

  2. And I'm learning about snow all over again!

    Got our first winter storm headed in, with 3"~5" expected Sunday night/Monday morning.

    And the temps will be 30* Monday, and 19* Monday night.

  3. After 2004, Florida insurance regulator did not allow insurance companies to not-renew coastal policies they now decided were too risky. Either renew all policies, or not do business in Florida. Yet another way prudent risk-takers subsidize careless risk-takers.

    Exaggerating danger always leads to the public demanding more government. Gore's movie said fossil fuel use leads to hurricanes. Presto! You have more hurricanes. Older rating of hurricanes relied on minimum central pressure, and 982 is not an exciting number.

    1. I think something here isn't quite right. After the '04 hurricanes, I think it was '06, State Farm dropped us. We live east of I-95 but still on the mainland, and State Farm dropped everyone living east of 95 around here. When we complained to our agent, she said they had dropped her insurance, too. It's not due to any claims in particular, just a re-assessment of the risks.

      We were able to go with another insurance company, but I think the state's mechanism is (was?) a high risk pool insurance to cover the beaches and mobile home parks. At least then, and it's far enough back that it's not in my computer records which go back to 2010, the insurance companies could drop policies.

    2. Agree, your report and the googles now don't match my memories of news then.

      "State Farm Florida president Jim Thompson said that even without any major hurricanes in the past three years, the Florida operation has been losing $20 million a month and was on pace to go insolvent by 2011. Losing a recent legal battle to hike its property insurance rates by an average of 47 percent was the last straw, he said."

      "State Farm blamed the decision to pull out, in part, on the state-imposed doubling of discounts for property owners who shore up their homes against hurricane damage (the Windstorm Mitigation Discount Program)."

      "McCarty said his office is also working with state Sen. Mike Fasano, R-New Port Richey, to develop legislation that will limit the number of polices a company can drop in a year. Fasano wants that legislation to be retroactive."

      First they came for your home insurance, then they came for your doctor and your health insurance.

    3. When my I was asking my wife if she remembered exactly when it was, she thought it was after '06. The earliest record I have in my computer is a 2010 payment to our current homeowners ins.

      I've always said that when the return on investment becomes greater for a politician than improving the products, that's where the money ends up being spent. The state has essentially taken over the insurance industry with one of state commissions, like the utilities. I'd suspect that state insurance commissioner is a position with a lot of perks.

      We had some minor damage in the two '04 hurricanes and State Farm was stellar in how they handled it. In addition, the way they handled our claims from our bike accident around New Years of 2000 was exemplary. I have no problems with them.

  4. It is now the morning after and I just looked at a lot of the surface observations along the gulf coast. I couldn't even find a tropical storm. Did I miss something?

  5. Also check