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NorthGeorgiaWX

Hurricane Dorian (05L)

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10 minutes ago, NorthGeorgiaWX said:

My dad who is 91, has been taking care of here his whole time. I can't imagine the struggle and can't imagine what it's like to watch your wife, that you've known for all practical purposes, all of his life, slowly fade away. It's sad enough as it is, but to actually live it on a daily basis... I hope I never have to know. As far as I'm concerned... the man is a saint. 
 

My prayers are with you and your family, stay safe.

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6 minutes ago, NorthGeorgiaWX said:

I may have a problem getting there though... I'm hearing of gas stations even in Orlando without gas. For me, it's about 560 miles and 8 hours, so I have to get gas at least once on the way, and that is usually after I get into Florida. I need to do some planning. And take extra gas cans. 

Take cans and stop in north Florida!

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No U.S. LANDFALL  ?   LOL   This is what i was asking about Steve .  The steering because of changes in timing

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It is possible, but I doubt the NHC will change much at 5 pm as far as track goes. They need more consensus than one Euro run. 🙂 The ensembles come in around 3:30, so I'd wait to see how those turn out first. 

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Going out on a limb.. I think the Euro will come back.  I question the Euro at this range ~4 days out) with tropical systems. Only time will tell though. If it starts coming back around tomorrow, we'll know. If not... we'll know. 😜

 

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1 minute ago, KingOfTheMountains said:

Ensemble mean was even further offshore. If this does end up being right, chalk it up as another huge win for the European model. 

Let's talk PR   With the coming of the internet craze the NHC/AND tv meteorologist has taken a beating, along with the government.  Of course i understand the politics part of it with global warming and the global govt implication. If Dorian never hits U.S. soil and brushes along the coast and most of the damage is surge i am afraid the integrity of the NHC will again be weakened.  All i read when the initial talk began was "don't pay the hype any attention.  NOAA is also part of the commerce Dept.   Could there be a controversy brewing?

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The NHC has done a great job with this so far. People get upset because they don't jump on every model change, but they shouldn't. Models are just tools, the model models the better because then you get to look at all the options, find a consensus, and go with it. Their track and intensity errors go down year after, so I'm not sure what they are doing wrong. 

I'll say this too... way too much emphasis is placed on the Euro and its solutions. It's good but it's not always right. I want to see the overnight models (all of them) before I change my mind about what I've seen this afternoon. I watched the Euro lose it last year with Florence when it came up with a path that no one else had, and it was wrong.  For me to have confidence in a model run, there needs to be a consensus from other models, ensembles, etc, and right now, other than its own 12z ensembles, it's not there.  Who knows, it may be in the morning. But I certainly would not change my forecast based on one set of model runs, take note yes, but flipping around from run to run is not meteorology, it's modelology.

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Posted (edited)

My wife and Ii was speaking of this.  Help us understand.  If models are tools, then why dismiss what they say?  How do you know which one is correct? I watch James Spann everyday  walk us through the GFS/Euro.  Then he gives us the temps from those models?  How do meteorologists predict if not with the tools?  How do you know when to dismiss what you programmed to give you that "certain" answer?

Edited by RickyD

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So I'm not a meteorologist and I didn't sleep in a Holiday Inn last night, but ... my day job involves building computational models to make decisions in a problem domain.  Broadly: its really, really hard.  If you're at a point where you need to build these sorts of things to make decisions, you're already in a complex (I mean that in a technical sense) domain with lots of feedback loops that you don't understand.

My armchair assessment of the issues in climate:

  1. It's complex and chaotic, and there are tons of feedback loops we don't even know exist
  2. The ones we do know exist, we probably don't fully understand
  3. Climate phenomenon are continuous and our data regimes are discrete
  4. Like so many other issues we assess and evaluate with computational models, we are constantly fighting a philosophical slide towards cryptoinductivism vs an improved Popperian approach - which is where meteorology shines relative to other disciplines, because meteorologists on social media and excellent sites like this one can share and argue (in a formal sense) their ideas in public and further the state of the domain knowledge
  5. ...but we're still extrapolating observations forward.  

I dont know anything about or anyone at NHC/NOAA but I am betting they have a process involving humans, models, and forecasts to put together their official releases.  I think they have so far properly balanced awareness with uncertainty in a very difficult forecast.

Backing up to your bigger question, the human consciousness has not evolved to be good at forecasting.  Humans are REALLY good at surviving the next five minutes with limited information and tools.  If your hunter gatherer ancestors woke up in a cave with their heads in the jaws of a sabre toothed tiger, they didn't study 10,000 other times that a human woke up in the same situations, they used what they know of the world and themselves to reason that the best path towards survival is to stab the thing in the eye, because humans have eyes too, and when something gets in your eye you cant see, etc.

So we invented computers to do this thing that we aren't very good at but we're still driving the computers and we still aren't really oriented towards forcasting and data and so on.  Its just not what we do.  Little biological survival benefit to forecasting harvests for next year if you're going to be killed by a tiger in your sleep.

I digress.

You get good at using models as tools by using them every day, staring at them every day, watching them handle different situations, setups, and so on, until you're like Thomas Hoving sniffing out phony ancient kouros statues just by looking at it.  Essentially you take forecasting and you turn it into a thing that we are good at.

This is a long and difficult question, not least because the closer you look at complex phenomenon, the less they make sense.

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Off the shore is in the cone so the forecast from the NHC would be absolutely right. If the public/media wants to bash the NHC because they don't understand the forecast products then that's on them. The same stuff happened after Irma when in reality they nailed what was an abnormally difficult forecast. The NHC has made leaps and bounds improvements over the past two decades and their forecasts are only getting better. As for the models, it's a numbers thing. They are quite literally numerical models, essentially a game of probability. Experience and knowledge allow them to read these outputs, and their inherent weaknesses, in ways that we never could. 

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Friday, August 30, 5 PM Discussion Update

Hurricane Dorian Discussion Number  26
NWS National Hurricane Center Miami FL       AL052019
500 PM EDT Fri Aug 30 2019

High resolution satellite images show that Dorian's cloud pattern
has become much better organized, with a distinct eye surrounded by
a ring of very deep convection and fair upper-level outflow.
Satellite intensity estimates, both objectives from CIMMS and
subjective from TAFB and SAB, are in good agreement with the 100-kt
winds recently measured by a reconnaissance aircraft. This is the
intensity assigned to Dorian in this advisory.

Since the upper-level environment is already becoming more favorable
for intensification and Dorian will be over high sea surface
temperatures, the NHC forecast calls for additional intensification.
Dorian is expected to be an extremely dangerous major hurricane as
it moves through the northwestern Bahamas and near the east coast of
the Florida peninsula in about 2 to 4 days.

The ridge over the western Atlantic appears to be already building
to the north of Dorian and is beginning to force the hurricane on a
more west-northwest track or 300 degrees at 9 kt.  The ridge is
forecast to build even more and steer Dorian on a westward track for
the next 3 to 4 days
. However, the steering currents will then
weaken, and this should result in a decrease in the hurricane's
forward speed. Given the collapse of the steering currents, the
track forecast by the end of the forecast period is highly
uncertain, and any small deviation in the track could bring the
core of the powerful hurricane well inland over the Florida, keep
it near the coast, or offshore. The models have not been very
consistent from run to run in terms of the timing of the northward
turn, but there are more models now indicating that the turn could
occur near the east coast of Florida instead of well inland.  Given
this latest change, the NHC forecast has been shifted just a little
to the right at this time, but users should be prepared for
additional adjustments to the left or right depending on future
model trends.

Based on the new forecast, a hurricane warning has been issued for
portions of the northwest Bahamas. However, given the slower
forecast speed of Dorian, it is too soon to issue and watches for
the Florida coast at this time.

Key Messages:

1. Life-threatening storm surge and devastating hurricane-force
winds are likely in portions of the northwestern Bahamas, where a
hurricane warning is in effect. Residents should execute their
hurricane plan and listen to advice given by local emergency
officials.

2. Life-threatening storm surge and devastating hurricane-force
winds are likely along portions of the Florida east coast by early
next week, but since Dorian is forecast to slow down and turn
northward near the coast, it is too soon to determine when or where
the highest surge and winds will occur. Residents should have their
hurricane plan in place, know if they are in a hurricane evacuation
zone, and listen to advice given by local emergency officials.

3. A prolonged period of storm surge, high winds and rainfall is
possible in portions of Florida into next week, including the
possibility of hurricane-force winds over inland portions of the
Florida peninsula.

4. Heavy rains, capable of life-threatening flash floods, are
expected over portions of the Bahamas and coastal sections of the
southeastern United States this weekend through much of next week.

FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 25.0N  70.7W  100 KT 115 MPH
 12H  31/0600Z 25.6N  72.0W  105 KT 120 MPH
 24H  31/1800Z 26.2N  73.8W  110 KT 125 MPH
 36H  01/0600Z 26.5N  75.4W  115 KT 130 MPH
 48H  01/1800Z 26.8N  76.9W  120 KT 140 MPH
 72H  02/1800Z 27.0N  78.8W  120 KT 140 MPH
 96H  03/1800Z 27.5N  80.4W  120 KT 140 MPH...NEAR FL EAST COAST

120H  04/1800Z 30.0N  81.5W   85 KT 100 MPH...INLAND

205152_5day_cone_no_line_and_wind.png.9d476062c9e1bcc319f144400519f0d5.png

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57 minutes ago, RickyD said:

My wife and Ii was speaking of this.  Help us understand.  If models are tools, then why dismiss what they say?  How do you know which one is correct? I watch James Spann everyday  walk us through the GFS/Euro.  Then he gives us the temps from those models?  How do meteorologists predict if not with the tools?  How do you know when to dismiss what you programmed to give you that "certain" answer?

Model results are discarded all the time. 

Every morning I post the Weather Prediction Center "Model Diagnostic Discussion" here:

It gives a lot of insight as to how the models are used to develop a forecast. You might hear Spann talk about the GFS and Euro, but look at the additional models the WPC uses in their forecast. It's a complex process to generate a forecast and models are only one set of tools that a meteorologist will use. Upper air soundings are are just one example of a tool that not only gets assimilated into the model ingest, but also data that is used immediately. 

Models are "guidance" not gospel. They give you clues. And all models have biases under certain conditions. Experienced meteorologist use that knowledge to see when a model is "correct" or maybe off a little due to the bias. I highly recommend that you read those diagnostic discussions for a better perspective on how models are used... or not. 🙂

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