Hurricane Irene Model and Forecast Discussion

[phil882]

Euro makes landfall at Cape Lookout 42h, exits at Kill Devil Hills approx 50h, eye grazes Ocean City 60h, 2nd landfall at Atlantic City 63h, hugs the NJ coast just inland and goes right over NYC between 66h and 69h.

First Landfall

[weatherdude]

I agree. That huge wobble could mean something. But new models won't pick it up until 6 or 12z.

No changes it looks like to the 2am track.

Exactly correct Mike2010. "Could mean something". That's where I was coming from! The fact that 00z based models don't see what is going on since about 02z should not amaze anyone. They are 00z models because they initialized on observed global data ending at 00z. Trends that developed after 00z obviously would not be seen yet by the 00z Euro or GFS or any 00z model. The 06z might get it because NCEP will attempt to initialize the model on the latest position information available at 6z.

[negative-nao]

It looks like this satellite animation shows the cold front interacting

http://wxweb.meteostar.com/models/noaaport_loop.php?PATH=/var/www/leads_images/satellite/NHC/IR/

[jconsor]

I agree that Irene has been moving to the right of the NHC track this evening. However, the recon fixes show that since 1z Irene has been moving at 3 degrees (just a tad east of due north). There hasn't been anything close to 20-30 degree motion. Recent recon fixes:

23Z 27.47N 77.33W

02Z 27.82N 77.35W

03Z 28.07N 77.33W

05Z 28.47N 77.3W

Irene has been deviating to the right of the official NHC track all evening. Before the 03z track update the storm started moving almost straight north, which was a right side deviation from the previous track, so at 3z, NHC made the track more northerly and the storm has started moving more to the right. NHC track is toward 350 or 360 and the storm is moving closer to 20 or 30 degrees. Seems to be a lot more than a wobble and this may have serious ramifications on future track projections. At this link, click on the "trop pts" at the top to see the official track. http://www.ssd.noaa..../flash-vis.html This picture shows the deviation that was already happening to the previous track before the 03z update. This is more than a "wobble".

[mike2010]

Exactly correct Mike2010. "Could mean something". That's where I was coming from! The fact that 00z based models don't see what is going on since about 02z should not amaze anyone. They are 00z models because they initialized on observed global data ending at 00z. Trends that developed after 00z obviously would not be seen yet by the 00z Euro or GFS or any 00z model. The 06z might get it because NCEP will attempt to initialize the model on the latest position information available at 6z.

Exactly what I was thinking. I'm throwing all of 0z out including the Euro. That was a huge wobble without a doubt.

sleepy time....night guys.

[BethesdaWX]

Exactly correct Mike2010. "Could mean something". That's where I was coming from! The fact that 00z based models don't see what is going on since about 02z should not amaze anyone. They are 00z models because they initialized on observed global data ending at 00z. Trends that developed after 00z obviously would not be seen yet by the 00z Euro or GFS or any 00z model. The 06z might get it because NCEP will attempt to initialize the model on the latest position information available at 6z.

It has been a slight Right bend but nothing close to what you cited earlier, The turn more NNE began at around 7-8PM though and there was the 11PM recon report , ECMWF should have it @ initializes with data into the 1AM EST/11PM advisory unless I'm screwing something up? As it seemed previously we had several "wobbles" while it was on its NW track and it could be expected to avg out over time.

Not that I know exactly what I'm talking about but It doesn't seem to be that far off course especially now that it has resumed due N movement.

[Jebman]

Here is the GFDL wind swath.

Am I correct in interpreting the GFDL model as depicting Woodbridge VA with 95 kt winds at 900 hPa?

Just unbelievable

There is going to be considerable damage

[RU848789]

So, it appears most of the models at 00Z have moved east of where they were earlier. Anyone care to speculate on whether this is just a minor fluctuation or if it indicates some synoptic feature (like the Canadian trough on Saturday "digging" less and not pulling the cyclone NNE-ward as much (letting it go further E) change? Obviously, 50-75 miles difference in the track can make a huge impact in winds/surge/rain in the NJ/NYC area and elsewhere (sounds like the usual major snowstorm discussion, lol).

[phil882]

ECWMF is slightly east... but not enough to bring it back over open water and it looks like its weakening rather quickly the entire time.

[LovintheWhiteFluff]

So, it appears most of the models at 00Z have moved east of where they were earlier. Anyone care to speculate on whether this is just a minor fluctuation or if it indicates some synoptic feature (like the Canadian trough on Saturday "digging" less and not pulling the cyclone NNE-ward as much (letting it go further E) change? Obviously, 50-75 miles difference in the track can make a huge impact in winds/surge/rain in the NJ/NYC area and elsewhere (sounds like the usual major snowstorm discussion, lol).

It appears the solutions are between 6 to 9 hours faster depending on the model. The faster solutions don't interact with the trough enough and allows the cyclone to head more NE, while the slower solution gets pulled more north. The key will be the speed of the cyclone the next 24 or so.

[weatherdude]

It has been a slight Right bend but nothing close to what you cited earlier, The turn more NNE began at around 7-8PM though and there was the 11PM recon report , ECMWF should have it @ initializes with data into the 1AM EST/11PM advisory unless I'm screwing something up? As it seemed previously we had several "wobbles" while it was on its NW track and it could be expected to avg out over time.

Not that I know exactly what I'm talking about but It doesn't seem to be that far off course especially now that it has resumed due N movement.

The 00z ECMWF initialized on a global data package as close to 00z, 8PM EDT, as possible. 00z is the data cutoff for ALL 00z models. The fact that the model output does not arrive until 1:43 AM EDT and beyond does not change anything, and it gets absoutley no further information after 8 PM EDT. The high resolution Euro model takes that long for the ECMWF to run and produce the grib files that they transmit to their customers around the world.

Yes and perhaps I overstated the degree of the deviation, but it is deviating to the right, and apparently weakening on IR....

[wxmeddler]

Am I correct in interpreting the GFDL model as depicting Woodbridge VA with 95 kt winds at 900 hPa?

Just unbelievable

There is going to be considerable damage

Thats an old graphic Jeb.. Besides, unlike thunderstorms. Hurricanes don't *usually* mix their winds to the surface once on land. What is aloft, stays aloft. In Irene's case here, I checked and we do have an inversion, so no mixing. Sorry..<br>

[SnowGoose69]

ECWMF is slightly east... but not enough to bring it back over open water and it looks like its weakening rather quickly the entire time.

This setup could see similar results to the mega-wind event last year where JFK gusted to 75 mph and many outages occurred on the south shore but once 5 miles inland on LI there were much less stronger winds and fewer outages. You can sort of see the Euro indicating the stronger winds right near the south shore.

[atownwxwatcher]

The 00z ECMWF initialized on a global data package as close to 00z, 8PM EDT, as possible. 00z is the data cutoff for ALL 00z models. The fact that the model output does not arrive until 1:43 AM EDT and beyond does not change anything, and it gets absoutley no further information after 8 PM EDT. The high resolution Euro model takes that long for the ECMWF to run and produce the grib files that they transmit to their customers around the world.

Yes and perhaps I overstated the degree of the deviation, but it is deviating to the right, and apparently weakening on IR....

Looks to me like an eyewall replacement cycle is happening and the CDO is expanding..They said that IRENE would become a large storm and that looks to be the case..and I also think some weakening is possible due to the ERC..

[BethesdaWX]

The 00z ECMWF initialized on a global data package as close to 00z, 8PM EDT, as possible. 00z is the data cutoff for ALL 00z models. The fact that the model output does not arrive until 1:43 AM EDT and beyond does not change anything, and it gets absoutley no further information after 8 PM EDT. The high resolution Euro model takes that long for the ECMWF to run and produce the grib files that they transmit to their customers around the world.

Yes and perhaps I overstated the degree of the deviation, but it is deviating to the right, and apparently weakening on IR....

Whats with the huge letters man? When looking at the initialization point on the 00z Euro it looks right about on target to where the storm was at the time, and actually moved it due north.

And it seems to be going through an ERC? Conditions appear doable for strengthening, the wind field is absolutely huge though.

[atownwxwatcher]

Posted by chicago storm in the other thread...

Latest recon pass showing a 942mb pressure and max FL winds of 110kts in the NE quad. Eyewall is still open too.

URNT12 KNHC 260708

VORTEX DATA MESSAGE AL092011

A. 26/06:42:20Z

B. 28 deg 50 min N

077 deg 23 min W

C. 700 mb 2588 m

D. 75 kt

E. 114 deg 13 nm

F. 210 deg 106 kt

G. 127 deg 49 nm

H. 942 mb

I. 8 C / 3057 m

J. 19 C / 3052 m

K. 17 C / NA

L. OPEN S - WNW

M. C20

N. 12345 / 07

O. 0.02 / 1 nm

P. AF304 2409A IRENE OB 18

MAX OUTBOUND AND MAX FL WIND 110 KT NE QUAD 07:00:00Z

source

And according to dan88 it is indeed an ERC taking place with the outer eyewall starting to take over..

[BethesdaWX]

Posted by chicago storm in the other thread...

Latest recon pass showing a 942mb pressure and max FL winds of 110kts in the NE quad. Eyewall is still open too.

URNT12 KNHC 260708

VORTEX DATA MESSAGE AL092011

A. 26/06:42:20Z

B. 28 deg 50 min N

077 deg 23 min W

C. 700 mb 2588 m

D. 75 kt

E. 114 deg 13 nm

F. 210 deg 106 kt

G. 127 deg 49 nm

H. 942 mb

I. 8 C / 3057 m

J. 19 C / 3052 m

K. 17 C / NA

L. OPEN S - WNW

M. C20

N. 12345 / 07

O. 0.02 / 1 nm

P. AF304 2409A IRENE OB 18

MAX OUTBOUND AND MAX FL WIND 110 KT NE QUAD 07:00:00Z

source

And according to dan88 it is indeed an ERC taking place with the outer eyewall starting to take over..

Seems to be moving a bit W of due N now. Looks like still some internal structure issues but could be worked out while still over favorable waters.

My bias is evident...

[WeatherGuide]

Honestly looking at those last couple frames on satellite i think that the storm is back to pretty much due north. I think the wobble had more to do with an eyewall replacement cycle in progress than a true trend. Most storms that i've watched have wobbled in path during ERCs. so we're really nowhere different than where we were yesterday evening. Landfall is still going to come west of Hatteras i think.. how far is the question.

EDIT: seems as if what i said was just confirmed above and bethesda, you're seeing it too. This thing is gonna keep wobbling..

[atownwxwatcher]

Seems to be moving a bit W of due N now. Looks like still some internal structure issues but could be worked out while still over favorable waters.

My bias is evident...

Not really a bias ..if you check the most recent image posted over in that thread (post #690) it looks like the latest plot actually was N/W

[BethesdaWX]

NAM looked like it was gonna come west, wound up just being slower, maybe a hair west.

[SnowGoose69]

NAM looked like it was gonna come west, wound up just being slower, maybe a hair west.

It definitely is east later in the period. Landfall is on the twin forks of LI...this is exactly why NYC should have waited a bit longer before pulling the trigger on all of these moves. I'm not saying the 06Z NAM is correct but the fact all we need is a 50-70 mile shift east and NYC will have a very windy rainy day with generally offshore winds and minimal surge threat.

[Derecho!]

Yes and perhaps I overstated the degree of the deviation, but it is deviating to the right, and apparently weakening on IR....

As of the last VDM at 8:46 said deviation is all of TEN miles from the 11PM NHC forecast track.. Somehow I don't think model-tossing is in order.

[Derecho!]

It definitely is east later in the period. Landfall is on the twin forks of LI...this is exactly why NYC should have waited a bit longer before pulling the trigger on all of these moves. I'm not saying the 06Z NAM is correct but the fact all we need is a 50-70 mile shift east and NYC will have a very windy rainy day with generally offshore winds and minimal surge threat.

Ummmm..huh? NAM crosses Long Island in the precisely the same place at 06Z as it did at 0Z.

I hope this post was sarcasm.

I mean, even if it did move, you're questioning emergency management moves because of a 6Z NAM run for a tropical system?

[BethesdaWX]

It definitely is east later in the period. Landfall is on the twin forks of LI...this is exactly why NYC should have waited a bit longer before pulling the trigger on all of these moves. I'm not saying the 06Z NAM is correct but the fact all we need is a 50-70 mile shift east and NYC will have a very windy rainy day with generally offshore winds and minimal surge threat.

I'm wondering if the NAM is a good model to use for tropical systems? It being a Mesoscale Model and all, and the track of the system seemingly determined by synoptical issues in the timing/amplitude of the trough?

I am surprised the NAM has held so steady, it would be laughable if the NAM ended up nailing this while ECM, CMC, GFS, etc were to come around. I only say this in memory of 12/26...

[yak]

NHC's 5 a.m. advisory has max. sustained winds down to 110 m.p.h. with an ever-so-slight nudge to the right essentially paralleling the NJ shore line into Long Island.

[SnowGoose69]

I'm wondering if the NAM is a good model to use for tropical systems? It being a Mesoscale Model and all, and the track of the system seemingly determined by synoptical issues in the timing/amplitude of the trough?

I am surprised the NAM has held so steady, it would be laughable if the NAM ended up nailing this while ECM, CMC, GFS, etc were to come around. I only say this in memory of 12/26...

The 00Z GFS was only a bit west of where the last 2 NAM runs were in reality...I can believe the GFS, the ECM is the one I do not believe at all right now. And no, the NAM is not normally a good model to use with these but it performs better in my experience on tropical systems once they are close to the US and north of 30N....it performs way better on NC landfalls than Florida or Gulf Coast ones for sure.

[A-L-E-X]

It definitely is east later in the period. Landfall is on the twin forks of LI...this is exactly why NYC should have waited a bit longer before pulling the trigger on all of these moves. I'm not saying the 06Z NAM is correct but the fact all we need is a 50-70 mile shift east and NYC will have a very windy rainy day with generally offshore winds and minimal surge threat.

What about the piling of water down Long Island Sound similar to what Donna did? I dont think you need the storm to go west of you to get the city inundated. For some parts of the city a NE wind is much worse. This storm is going to be huge like 1944, Donna and Ike. 1944 did the same thing on the Jersey Shore and was well east of there also. Not to mention that the rainfall by itself could easily submerge some parts of the city, since we've had over a foot of rain in the past ten days.

[BethesdaWX]

The 00Z GFS was only a bit west of where the last 2 NAM runs were in reality...I can believe the GFS, the ECM is the one I do not believe at all right now. And no, the NAM is not normally a good model to use with these but it performs better in my experience on tropical systems once they are close to the US and north of 30N....it performs way better on NC landfalls than Florida or Gulf Coast ones for sure.

Ok thanks a bunch. Knowing the NAM is a Mesoscale model I am hard pressed to take it's QPF solution over the GFS which personally I really do not want to do. 06z GFS running now, fingers crossed

[Midlo Snow Maker]

6z gfs coming in a good bit SW of 0z at hr 30 (slower)

[A-L-E-X]

6z gfs coming in a good bit SW of 0z at hr 30 (slower)

slower/faster seems to be the key here in terms of whether it goes west or east of the last run, respectively.