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Hurricane Irene Model and Forecast Discussion


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Regarding Phil's emphasis on the small vort max's that make the difference: there are currently three of them just offshore of the west coast right now. None of them are being sampled by anything other than satellite right now. The most critical piece might be the one offshore due west of OR right now -- how fast that piece moves and how it amplifies when it gets east of the Mississippi will determine how much Irene "hooks" to the left, so to speak. That won't be moving onshore into the RAOB network for another 24-36 hr. The 26/1200 UTC and 27/0000 UTC suites of models may be the most critical in the next few days.

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Here is why the ECWMF solution is sorta coming out of left field (pun intended ;) )

What we have is a small vortmax that essentially is forced southward due to the low heights caused partially by Irene. However, this vortmax has mass too which actually causes Irene to be pulled slightly leftward just like the vortmax is being forced south and rightward. The effect is pretty small on Irene when you think about it, but its enough to shift its track to the north instead of further to the north-northeast like the GFS is suggesting.

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Regarding Phil's emphasis on the small vort max's that make the difference: there are currently three of them just offshore of the west coast right now. None of them are being sampled by anything other than satellite right now. The most critical piece might be the one offshore due west of OR right now -- how fast that piece moves and how it amplifies when it gets east of the Mississippi will determine how much Irene "hooks" to the left, so to speak. That won't be moving onshore into the RAOB network for another 24-36 hr. The 26/1200 UTC and 27/0000 UTC suites of models may be the most critical in the next few days.

Yep... and that's why we will likely still see some significant changes in the runs to come. If this feature continues to trend just a little bit stronger, it could pull Irene even further west. Without any sort of massive trough coming in to swoop up Irene, little features like this are going to make the difference is shifting the storm motion vector as it nears landfall.

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What kind of impacts would NYC Metro area be looking at as depicted by the Euro?? I would think there would still be substantial impacts.

Yep... and that's why we will likely still see some significant changes in the runs to come. If this feature continues to trend just a little bit stronger, it could pull Irene even further west. Without any sort of massive trough coming in to swoop up Irene, little features like this are going to make the difference is shifting the storm motion vector as it nears landfall.

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What kind of impacts would NYC Metro area be looking at as depicted by the Euro?? I would think there would still be substantial impacts.

Alot of rain and strong winds but not likely anything truly dire. The system would be a strong TS at best after being over VA, the DE/MD region and NJ. The issue would be a nasty storm tide, not necessarily a true storm surge per say but much above normal high tides over the south shore of LI and Brooklyn which would likely cause floooding, overall though in terms of structural and tree damage, and power outages NYC would get away with this if the Euro track verified if you ask me.

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I still think there could be minor structural damage, disagree with you on the tree damage and power outages though. The ground is quite saturated in some areas due to the recent heavy rains so it won't take much in terms of wind for tree damage to occur, power outages could still be quite widespread as well. Also with what the Euro is depeicting, that would place us in the right front quadrant of the storm which is usually where the strongest winds occur, I could still see this as a Cat 1 on the Euro, this may be more dependent on how quickly Irene will be moving.

Alot of rain and strong winds but not likely anything truly dire. The system would be a strong TS at best after being over VA, the DE/MD region and NJ. The issue would be a nasty storm tide, not necessarily a true storm surge per say but much above normal high tides over the south shore of LI and Brooklyn which would likely cause floooding, overall though in terms of structural and tree damage, and power outages NYC would get away with this if the Euro track verified if you ask me.

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Please tell me if I am wrong, but it seems like we will not know what is going to happen until the cold front/trough goes through the mid-atlantic area. It seems like once it has gone through the models will have a better idea of what will happen in the mid-atlantic area. So we may not know until Friday what will happen here in the NY metro area. Right now it seems like the models are trying to figure that out and thus the changes in the models.

Thoughts?

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I still think there could be minor structural damage, disagree with you on the tree damage and power outages though. The ground is quite saturated in some areas due to the recent heavy rains so it won't take much in terms of wind for tree damage to occur, power outages could still be quite widespread as well.

Then why did you ask him lol? The more time the storm has over land the more time it has to weaken obviously. Trend could fly back east in a heartbeat, but if the 00z Euro were to come to fruition it wouldn't be a huge deal for NYC.

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Then why did you ask him lol? If the more time the storm has over land the more time it has to weaken obviously. Trend could fly back east in a heartbeat, but if the 00z Euro were to come to fruition it wouldn't be a huge deal for NYC.

The fact we have seen the Euro pull this move a few times before on systems in this region, most notably Isabel as I mentioned earlier makes me believe this could be the start of a shift westward.

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The fact we have seen the Euro pull this move a few times before on systems in this region, most notably Isabel as I mentioned earlier makes me believe this could be the start of a shift westward.

Thankyou very much for the analysis, I learn alot from you red-taggers :hug:

Also couldn't agree more, especially noting the GFS has shifted a bit west and is usually lagging the Euro, and is now near the position of the 12z Euro. I admit I am a bit IMBY biased and am pulling for the Euro (shame on me would do significant damage).

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He wasn't the one I asked in this thread, it was Phil882, but his input was greatly appreciated. I still think NYC would see substantial impacts if the Euro verified. As a matter of fact a met in another forum mentioned the NJ coast would still see 70-80kt winds with what the Euro is depicting.

Then why did you ask him lol? The more time the storm has over land the more time it has to weaken obviously. Trend could fly back east in a heartbeat, but if the 00z Euro were to come to fruition it wouldn't be a huge deal for NYC.

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He wasn't the one I asked in this thread, it was Phil882, but his input was greatly appreciated. I still think NYC would see substantial impacts if the Euro verified. As a matter of fact a met in another forum mentioned the NJ coast would still see 70-80kt winds with what the Euro is depicting.

Well it seems you already have an opinion formed then, ok. S NJ Coast vs N NJ coast is a different animal on the 00z ECMWF for sure, NYC is even further up. Things change so the current runs is by no means the actual solution.

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He wasn't the one I asked in this thread, it was Phil882, but his input was greatly appreciated. I still think NYC would see substantial impacts if the Euro verified. As a matter of fact a met in another forum mentioned the NJ coast would still see 70-80kt winds with what the Euro is depicting.

I'm sure that would be the southern Jersey coast. It would definitely be a lot weaker by the time it gets up here, after spending that much time on land. I would love to experience some hurricane force gusts, but it won't happen if 0z EURO is correct. That's way too far inland.

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The fact we have seen the Euro pull this move a few times before on systems in this region, most notably Isabel as I mentioned earlier makes me believe this could be the start of a shift westward.

This is just silly. The stuff we run nowadays has such little resemblance to the operational models of 2003.

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Well it seems you already have an opinion formed then, ok. S NJ Coast vs N NJ coast is a different animal on the 00z ECMWF for sure, NYC is even further up. Things change so the current runs is by no means the actual solution.

Its hard to believe the Euro at this juncture. Could be right, but my money is on east of that type of track. Its rare and a bit questionable based on synoptics. People were ready to call this a whiff at this time last night. TCs are poorly handled systems and quite a bit worse handled than mid-latitude cyclones in the winter. So if you are uneasy about 96 hour trends in the winter, then apply that to this except multiply in more uncertainty.

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Its hard to believe the Euro at this juncture. Could be right, but my money is on east of that type of track. Its rare and a bit questionable based on synoptics. People were ready to call this a whiff at this time last night. TCs are poorly handled systems and quite a bit worse handled than mid-latitude cyclones in the winter. So if you are uneasy about 96 hour trends in the winter, then apply that to this except multiply in more uncertainty.

I can see your point, definitely. Phil mentioned earlier (I think), the Euro is showing a stronger shortwave over the continental US diving further south pulling Irene Northward a bit before turning back on the NNE path. Is that what you feel is "hard to believe"? I don't know enough about these type of synoptical systems to have any opinion, but It looks like if the Euro has It's overall Synoptics right then the track would make sense.

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I can see your point, definitely. Phil mentioned earlier (I think), the Euro is showing a stronger shortwave over the continental US diving further south pulling Irene Northward a bit before turning back on the NNE path. Is that what you feel is "hard to believe"? I don't know enough about these type of synoptical systems to have any opinion, but It looks like if the Euro has It's overall Synoptics right then the track would make sense.

Without a deep trough, we've never seen a hurricane get sucked NNW above 35N...but its certainly possible here. But I just put my money on the typical model bias of underdoing the westerlies at the those latitudes and their tendency to over-phase TCs with shortwaves. We'll see if this storm bucks that trend, but I know I personally doubt it.

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First outer bands showing up on the Miami radar http://www.daculawea...torm_mode_1.php

Looks like many of the storms are moving 50-60 mph.

These are all GRLevel3 loops, I hope to get base velocity, echo tops, and storm rain totals loops going for all of those sites today.

Miami FL Composite

Melbourne FL Composite

Jacksonville FL Composite

Charleston SC Composite

Wilmington NC Composite

Morehead City NC Composite

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Without a deep trough, we've never seen a hurricane get sucked NNW above 35N...but its certainly possible here. But I just put my money on the typical model bias of underdoing the westerlies at the those latitudes and their tendency to over-phase TCs with shortwaves. We'll see if this storm bucks that trend, but I know I personally doubt it.

Ok. Was wondering in this case the synoptical setup is different in that I don't think there are many analog storms to choose from (with the slow movement N and the Shortwave of the strength being depicted on the ECMWF), this should be interesting I guess. I don't have your knowledge base here but the fact that the ECMWF is right in the middle of its Ensembles gives some reason think this may be the one.

Also I am a bit IMBY biased, though I'm trying my best to be objective ;)

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Without a deep trough, we've never seen a hurricane get sucked NNW above 35N...but its certainly possible here. But I just put my money on the typical model bias of underdoing the westerlies at the those latitudes and their tendency to over-phase TCs with shortwaves. We'll see if this storm bucks that trend, but I know I personally doubt it.

I agree that the synoptics are quite tenuous. The ECMWF seems to be relying on one small vort to keep Irene moving N as opposed to curving more NNE, and I don't have a huge amount of confidence that such a small vort can do the trick. However, I do want to note that the 0z ECMWF doesn't show any west of north component north of 30N - see animation below.

5ef769abb2f7efb6e8cba203c11619e9.gif

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