Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

Hurricane Isaac, Part 3 - Analysis and Forecasting Thread


Recommended Posts

Lots of jargon I'm more interested in results. The model is pretty iffy in most cases I've seen.

Yeah I really don't know the results to be honest and I have no experience with this other than the stuff I mentioned in the post. I'm basically just as interested to see how it does.....it certainly wasn't a top model for me to ever look at in terms of tropical systems.

Link to comment
Share on other sites

  • Replies 924
  • Created
  • Last Reply

In testing it has shown some promise with tropical cyclones. I don't have numbers in front of me, but I have sat in on the training sessions for it. That's not saying it is right on this one, but the results so far have raised my interest.

Fair enough. Some folks have been calling for imminent intensification so much it's hard to believe them at thus pt... At least from an outside observer. Good thing most models don't run every hour..!

Link to comment
Share on other sites

I haven't used it in this type of a tropical situation before, but I have to say that overall I have found the HRRR to be a quite useful tool for convective forecasting in the spring and summer for my own needs. I certainly would not refer to it as a third rate model personally. I mean, it isn't perfect by any stretch, but I think it does a pretty good job showing convective mode, strength, etc.

I use it for convection too. I've had both success and head scratchers with it...but if you know how to use it, I think it's a good tool as far as convection goes.

Link to comment
Share on other sites

WDSU met just said the same thing.

I'm going to hazard a guess that said "models" are the HWRF, plus the BAMD, BAMM, BAMS, and God forbid, CLIPER. HWRF is the only legitimate model of the bunch, and there aren't any actual new 0Z models out yet besides the NAM, and that's directly over New Orleans.

Link to comment
Share on other sites

I haven't used it in this type of a tropical situation before, but I have to say that overall I have found the HRRR to be a quite useful tool for convective forecasting in the spring and summer for my own needs. I certainly would not refer to it as a third rate model personally. I mean, it isn't perfect by any stretch, but I think it does a pretty good job showing convective mode, strength, etc.

It is well known in this region that it is a top dog for sniffing out banding during winter storms - many meteorologists in the KPAH area love using it. But - that is for winter storms. It has its own little issues - during winter storms - you have to monitor trends on radar. If you see banding starting to cause problems in your area it is nice to compare with the HRRR and more times than not the HRRR has picked up on that potential.

It is also easy to dismiss the HRRR early on during a winter storm - seems like it is either hot or not. But you can tell that once a storm is underway. Lot of mets like it in this region. But again - you have to learn to feel it out.

I have noticed that it doesn't do well in the overall snowfall forecasts - but better with banding.

I don't know much about it for tropical weather. Just a lot of people commenting that they have been watching it the last few days and that it has done well.

Seems to have some value when watching the trends from one run to the next - which is easy to do with the way they have the menu laid out.

Link to comment
Share on other sites

Yeah I really don't know the results to be honest and I have no experience with this other than the stuff I mentioned in the post. I'm basically just as interested to see how it does.....it certainly wasn't a top model for me to ever look at in terms of tropical systems.

It might be useful... I'm not trying to say it's not at all but there sure is a lot of HRRR talk all of a sudden. I guess because the live view has remained so lame. Anyway... Not trying to derail just curious. On convection it seems to have an idea about half of the time and almost clueless the rest. Ill hope for a positive coin flip.

Link to comment
Share on other sites

Serious question: does the hrrr have known strengths in the tropics? It's usually a third rate model to kill time with when storm chasing. I find it very odd to see it so much tonight. Can only guess folks are having trouble making reaches otherwise.

I was wondering the same thing as I have never used it for dealing with tropical systems. I've found with bigger systems/events it has done a better job and when there is also more forcing. But those cap days in the plains, it can struggle sometimes as I'm sure you know. But with like the GHD blizzard, past few EC snowstorms, strongly forced svr wx events..it has done well most of the time.

Link to comment
Share on other sites

With Katrina, everyone in the media keeps stressing that it was a Cat 3 at landfall. True, but it was pushing a cat 4 and maybe a cat 5 storm surge. I don't think that surge suddenly shrinks to Cat 3 just because in the final six hours the wind velocity comes down.

I was just listening to him say that.

I don't know how accurate these predictions are

http://w1.weather.go...&threat=coastal

But - if they are right then the main story (which many of us already know) will be the flooding. I am surprised how much people are obsessed with whether this thing ends up with winds of 70-80-90 mph. I can understand the concern about wind - but the bigger story will be the 10-20 inches of rain and flooding.

I realize a lot of "us" are intrigued by storm structure and strengthening - will it/won't it - but from a meteorological point of view the concern is the surge and flooding - how long the fetch may be in from the southeast into areas that flood easily. Of course 10-20 inches of rain could overwhelm some areas.

Seems with a broad wind field that the build up of storm surge - combined with high tide - could make for a decent story maker.

I wonder how much of the general public focuses on storm intensity - specifically wind. I hate the NHC wind rating system. Does not tell the full story - not by far. People always want to know if it is a Cat 1 - 2 - 3 or what. It is almost like a light bulb goes on in their head if you give them the "right" number. Maybe that number is a 2 or maybe it is a 3 - depending on the person.

You don't see many people being interviewed that ask the question - so what is the storm surge going to be and how much rain are we expected

Some of the people I have seen interviewed are saying things like - ahhh it's only a tropical storm or a category 1 - not really worried.

Link to comment
Share on other sites

I was just listening to him say that.

I don't know how accurate these predictions are

http://w1.weather.go...&threat=coastal

But - if they are right then the main story (which many of us already know) will be the flooding. I am surprised how much people are obsessed with whether this thing ends up with winds of 70-80-90 mph. I can understand the concern about wind - but the bigger story will be the 10-20 inches of rain and flooding.

I realize a lot of "us" are intrigued by storm structure and strengthening - will it/won't it - but from a meteorological point of view the concern is the surge and flooding - how long the fetch may be in from the southeast into areas that flood easily. Of course 10-20 inches of rain could overwhelm some areas.

Seems with a broad wind field that the build up of storm surge - combined with high tide - could make for a decent story maker.

I wonder how much of the general public focuses on storm intensity - specifically wind. I hate the NHC wind rating system. Does not tell the full story - not by far. People always want to know if it is a Cat 1 - 2 - 3 or what. It is almost like a light bulb goes on in their head if you give them the "right" number. Maybe that number is a 2 or maybe it is a 3 - depending on the person.

You don't see many people being interviewed that ask the question - so what is the storm surge going to be and how much rain are we expected

Agree, When Irene hit up this way in the Hudson valley, there was little wind. We had exstensive damage inland damage from flooding.

http://www.huffingtonpost.com/2012/08/27/hurricane-irene-damage-statistics-2011_n_1832342.html?utm_hp_ref=natural-disasters

NEW YORK

Deaths: 10

Damage: More than $1.3 billion

Power outages: 1.1 million

Irene's eye made its third U.S. landfall in Brooklyn but did not materialize into the big-city disaster many had feared. The city had shut down its subway system for the first time in history and evacuated thousands of coastal residents. Only minor flooding was reported. But inland, the storm caused severe flooding that closed hundreds of roads and bridges. Tourist destinations in the Catskill and Adirondack mountains lost millions of dollars in revenue over the summer as they sought to repair damage to trees, hillsides and lakes that were drained by demolished dams.

Link to comment
Share on other sites

Still kept as a tropical storm but pressure now down to 979 mb. Amazing how low the pressure is now for a tropical storm. The new NHC forecasted intensity at landfall is also down from a Cat 2 to a Cat 1 (90 mph).

BULLETIN

TROPICAL STORM ISAAC ADVISORY NUMBER 28

NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012

1000 PM CDT MON AUG 27 2012

...ISAAC TAKING AIM ON THE NORTHERN GULF COAST...SIGNIFICANT STORM

SURGE AND FRESHWATER FLOOD THREAT EXPECTED...

SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION

-----------------------------------------------

LOCATION...27.1N 87.0W

ABOUT 190 MI...305 KM SE OF THE MOUTH OF THE MISSISSIPPI RIVER

ABOUT 255 MI...410 KM SSE OF BILOXI MISSISSIPPI

MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H

PRESENT MOVEMENT...NW OR 310 DEGREES AT 10 MPH...17 KM/H

MINIMUM CENTRAL PRESSURE...979 MB...28.91 INCHES

Link to comment
Share on other sites

I was wondering the same thing as I have never used it for dealing with tropical systems. I've found with bigger systems/events it has done a better job and when there is also more forcing. But those cap days in the plains, it can struggle sometimes as I'm sure you know. But with like the GHD blizzard, past few EC snowstorms, strongly forced svr wx events..it has done well most of the time.

Defin does a nice job in this region with severe weather events - when using all the different parameters. It holds promise for the coming years. I believe SPC is testing some higher resolution models - perhaps part of the HRRR - that are even better at convection. Some of their test case studies presented at conferences have been amazing - including some Derecho forecasting. But I digress :) - as well

Link to comment
Share on other sites

I was wondering the same thing as I have never used it for dealing with tropical systems. I've found with bigger systems/events it has done a better job and when there is also more forcing. But those cap days in the plains, it can struggle sometimes as I'm sure you know. But with like the GHD blizzard, past few EC snowstorms, strongly forced svr wx events..it has done well most of the time.

"Third rate" a bit strong.. more meaning it's not the first, or second, model I'd look at in most cases.. It's a time killer while you're waiting. ;) Maybe that's exactly as now.

Link to comment
Share on other sites

And hence why it may do better down in the tropics. Makes sense.

Potentially....

I can't say anything about its performance just noting that if your going to defend a model you probably should at least have a slight understanding of how it works.

Link to comment
Share on other sites

Potentially....

I can't say anything about its performance just noting that if your going to defend a model you probably should at least have a slight understanding of how it works.

Not necessarily defending it, just noting that some saw success in the tropics with it.

Lots of models out there and sometimes it's tough to remember or recall how they all work. Where it counts is knowing how to use it.

Link to comment
Share on other sites

I was wondering the same thing as I have never used it for dealing with tropical systems. I've found with bigger systems/events it has done a better job and when there is also more forcing. But those cap days in the plains, it can struggle sometimes as I'm sure you know. But with like the GHD blizzard, past few EC snowstorms, strongly forced svr wx events..it has done well most of the time.

The HRRR is a good meso model but I don't believe it's particularly specialized for the tropics, so other models like the GFDL, HWRF, UW-NMS/other university's models are likely better. I think people are getting the impression in this thread that it's really good since they usually don't see such high resolution model data, but it gets way better than that. Here's a screenshot of vorticity from the UW-NMS run at 300 m horizontal resolution (not isaac)...

post-645-0-79233400-1346122846_thumb.png

It's cool though that the HRRR updates so often, the good mesoscale hurricane models generally have a huge lag time which lowers their usefulness as a forecast tool.

Link to comment
Share on other sites

So I am posting this as much to ask if this makes sense: but wouldn't it seem that given how the low the pressure in this thing is, and how good the MW presentation is, if it managed to develop a persist ring of cold convection around the center that it could tighten up and intensify more rapidly than might otherwise be expected? I am not necessarily saying that we should expect that - more saying that theoretically wouldn't it make sense that a storm with an already extremely low pressure could see the winds "catch up" rather abruptly. I believe someone mentioned that Opal exhibited that sort of behavior.

Link to comment
Share on other sites

So I am posting this as much to ask if this makes sense: but wouldn't it seem that given how the low the pressure in this thing is, and how good the MW presentation is, if it managed to develop a persist ring of cold convection around the center that it could tighten up and intensify more rapidly than might otherwise be expected? I am not necessarily saying that we should expect that - more saying that theoretically wouldn't it make sense that a storm with an already extremely low pressure could see the winds "catch up" rather abruptly. I believe someone mentioned that Opal exhibited that sort of behavior.

To me, this makes complete and total sense. This thing shows signs (albeit gradual) of better organization, I would not be shocked at all to have solid and strengthening cat 2 at landfall.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...