The NHC still struggles mightily w/intensity

[otowntiger]

Its almost as if up until he made landfall in Cuba that they were dismissive of the effects that would have on his strength. I had my suspicions about it still being a major storm as it exited the Cuban coastline. I really had my doubts when after just the first couple of hours of being over land looking at the rapid decay of the system and the track he was on that he could survive as a major. This mornings discussion makes it sound as if they are surprised and in fact state that he is not even as strong as they deem in the advisory. Now they admit they aren't sure what to do with the intensity forecast. It is even a little funny to me that when a lot of the guidance is now telling them that the storm will not re-strengthen or at least not very much but for "consistency" sake they keep it as strong as they first said it would be as it makes US landfall. I guess it is better safe than sorry, but they really need to improve in this area to be more realistic.

[Derek Ortt]

intensity guidance is less reliable than our CIA. I only use it for trends and try to figure out why it is doing what its doing (SHIPS is easy to decipher since its a statistical model, but some of the others...)

[wxwatcher91]

I think one of the big factors for the extreme weakening of Dennis over Cuba was that Dennis took a jog to the west while over Cuba. This made Dennis stay over Cuba longer than if he just zipped through.

[arcticfire]

um , from what I can see whatever guidance was saying it would not re-stengthen was/is completly wronge.

[otowntiger]

um , from what I can see whatever guidance was saying it would not re-stengthen was/is completly wronge.

"Um" read the 5am discussion from the NHC itself. That's what I was referring to.

[arcticfire]

um , from what I can see whatever guidance was saying it would not re-stengthen was/is completly wronge.

"Um" read the 5am discussion from the NHC itself. That's what I was referring to.

From the 5am discussion:

SHIPS MODEL IS NO LONGER RE-INTENSIFYING DENNIS BUT THE
GFDL DOES.

I fail to see how that constitutes a "lot of guidance". Please feel free to explain why that model should be given so much wieght.

[recmod]

Wouldn't looking at current trends bear more weight than a model guidance? Anyone can clearly see on the IR loop that the convection is becoming much more intense with a better defined eye. When the hurricane was exiting the Cuban coast, there was just a very small ball of convection left. This has exploded into a large area of deeper convection in the past couple hours. If this does not indicate a trend toward strengthening, then I must be clueless...

--Lou

[Brent]

7am advisory:

105 mph Cat 2... 969 mb.

Not good.

[otowntiger]

um , from what I can see whatever guidance was saying it would not re-stengthen was/is completly wronge.

"Um" read the 5am discussion from the NHC itself. That's what I was referring to.

From the 5am discussion:

SHIPS MODEL IS NO LONGER RE-INTENSIFYING DENNIS BUT THE
GFDL DOES.

I fail to see how that constitutes a "lot of guidance". Please feel free to explain why that model should be given so much wieght.

Ask the NHC. Over the last several years in all of their forcast advisories they mention the ships model whenever they discuss intensity, more than any other. Rarely do they mention the GFDL regarding intensity.

Also read Soonertwister's post in another thread. He is a professional met by the way.

[arcticfire]

Well then it would seem to me they simply did not agree with the ships model. I'm sure they are pro's also and probly far better at deciding if a model is on target or giving a bogus prediction. So personally I don't see a fault in them using their expertise and experince to not give a ton of wieght to what a model says in one advisory.

[otowntiger]

Well then it would seem to me they simply did not agree with the ships model. I'm sure they are pro's also and probly far better at deciding if a model is on target or giving a bogus prediction. So personally I don't see a fault in them using their expertise and experince to not give a ton of wieght to what a model says in one advisory.

The whole point to this thread was, the NHC, by their own admission, whether they use models, their own judgement based on experience or a combination of both, does not have a firm grasp on intensity forecasts. That obviously played out when Dennis passed over Cuba and there are countless examples of storms past that they blew it on their intensity forecasts. Now when it comes to direction they are getting better and better and in fact are quite accurate, but until they get a handle on intensity they are only 50% successful in my opinion.

[arcticfire]

Well it's true they seem generally taken unawares with regards to strength I'm not sure how acruate they can really get. I think saying a major hurricane is likly to strike a select swath of a few hundred miles is pretty darn good days out.

Technology is progressing thow and I'm sure in a few decades they will start to get a really good handle on things.

[karenfromheaven]

The NHC is under tremendous pressure I'm sure, to provide an intensity forecast. Here in Bay County, they plan to issue mandatory evacuation orders for zones 1,2,3, and 4. So they are expecting a Cat 4 storm and are uprooting everyone accordingly. The zones appear to be set up to follow storm surge model predictions. I imagine they would prefer not to order too many people out unnecessarily. If the NHC did not provide their continuity forecast this morning, many emergency management centers would drop evacuation orders, only to have to reinstate them later, perhaps too late.

[birdwomn]

The NHC is under tremendous pressure I'm sure, to provide an intensity forecast. Here in Bay County, they plan to issue mandatory evacuation orders for zones 1,2,3, and 4. So they are expecting a Cat 4 storm and are uprooting everyone accordingly. The zones appear to be set up to follow storm surge model predictions. I imagine they would prefer not to order too many people out unnecessarily. If the NHC did not provide their continuity forecast this morning, many emergency management centers would drop evacuation orders, only to have to reinstate them later, perhaps too late.

I agree with you Karen. The NHC has to walk a tightrope from what I can see...stay true to the numbers and the science, but provide information that will allow people to make prudent plans well in advance. Not an easy call sometimes.

[HURAKAN]

Forecasting intensity has never been easy and for a long time, it won't be. Hopefully in the future we will understand better how a hurricane works and track and intensities will be better forecasted.

[Derek Ortt]

SHIPS is given so much weight because it is the best intensity forecasting model

Now, as I said earlier, it is very easy to see when it is producing BS and this time it obviously was since storms coming back into gradient balance are not factored in, neither is PV conservation

[Nimbus]

As mentioned by Dr Lyons last night the intensity forecast appears linked to the steering with Dennis.
The ridge is better developed in the lower levels so a weak storm would be steered further WNW.
If Dennis quickly regains his 50,000 foot cloud tops as he appears to be doing the steering may be different with more recurve.
This storm is a nightmare to forecast and the NHC has done a good job at striking a compromise track but we may not know for another 24 hours exactly where Dennis is going to make landfall if he doesn't follow the model guidance.

[MGC]

Cuba did more damage to Dennis than even I expected. I forecast Dennis to weaken 2 categories and he did just that. I was off a cat in my initial intensity at landfall, I predicted a Cat 3. I just don't know how some people including the NHC expected Dennis not to lose much intensity over Cuba. Considering the track Dennis was taking it was obvious Dennis was going to spend considerable time over land, not the couple of hours Charley did last year.......MGC

[otowntiger]

Now they are saying fluctuations in intensity is expected. What does that mean? I believe that it means that they expect it to weaken, but they are not sure. I'm not all that impressed with him right now, and I would be very surprised if he got a whole lot stronger than he is right now. We forget that it is still only July and the SST's are not as warm in the Gulf as they were down in the Carribean or as warm as they will be. My prediction is that he will make landfall in the vicinity of Mobile/Pensacola as a weak cat 2. No need for any of these things I see way too many of them from some posters here. If I'm way off base I will come back and post a few of these .

[sprink52]

On the Miami and Key West Radar loops you cann clearly see the eye again.