Hurricane Irene Model and Forecast Discussion

[mike2010]

Note that the NAM map projection on the left has due north not pointing straight up, while the satellite image on the right does; if you take that into account, the init looks fine to me.

thanks.

still seems a tad east when comparing the correct maps though.

[free_man]

All i've looked at with the NAM is it's initialization so far. Is it just me,or does it appear it initialized way east of where it should of ?

probably the difference in map projection.

[LakeEffectKing]

All i've looked at with the NAM is it's initialization so far. Is it just me,or does it appear it initialized way east of where it should of ?

75W drawn in.....initialized fine!

[BethesdaWX]

NAM is way west, looks like by 30 miles?

[EasternUSWX]

NAM is way west, looks like by 30 miles?

Wouldn't call 30 miles way west. Looks like about 50 miles to me.

[WhiteoutWX]

Wouldn't call 30 miles way west. Looks like about 50 miles to me.

Matches the GFS well now, maybe a hair west.

[LakeEffectKing]

Wouldn't call 30 miles way west. Looks like about 50 miles to me.

Well, in fairness, you don't know his point of reference time....it was 30 miles west earlier in the run....which at 24 hours out is indeed a significant (or "way") west change.

[meteorjosh]

Well, in fairness, you don't know his point of reference time....it was 30 miles west earlier in the run....which at 24 hours out is indeed a significant (or "way") west change.

NAM is hugging the coast to Queens/Nassau

[downeastnc]

Well, in fairness, you don't know his point of reference time....it was 30 miles west earlier in the run....which at 24 hours out is indeed a significant (or "way") west change.

As bad as the hit to NC is going to be as currently forecasted if the center were to come 30-40 miles west the impact would be much much larger. It would then have a much more damaging impact on the bigger cities that as of right now are only expect minimal hurricane conditions vs strong hurricane condtions if it is 30-40 miles west.

[BethesdaWX]

As bad as the hit to NC is going to be as currently forecasted if the center were to come 30-40 miles west the impact would be much much larger. It would then have a much more damaging impact on the bigger cities that as of right now are only expect minimal hurricane conditions vs strong hurricane condtions if it is 30-40 miles west.

It would weaken going over land. While the population living further inland would feel greater effects, (DC, Philly), the storm itself would be weaker and NYC/Boston would get off the hook so to speak.

[Bluescat1]

The NAM is far more bullish with precp. then the last couple of runs.

[downeastnc]

It would weaken going over land. While the population living further inland would feel greater effects, (DC, Philly), the storm itself would be weaker and NYC/Boston would get off the hook so to speak.

I am talking about in NC not up the coast, east of Hwy 17 in NC the towns as a rule are all small, however along and just inland of Hwy 17 you have lots of towns with 50-60K folks and then my town which is with the surrounding towns close to 150k. It would also mean more effect along and west of I95 and then we are tlaking a lot more people being affected.

[LakeEffectKing]

09z RSM and ETA (make up decent chunk of SREF's) have trended west of their respective 21z and 03z runs....SREF mean should follow suit...when it comes out in a few minutes.

Edit:

They're in....and it shifted west:

[wxsmwhrms]

NHC now has 90 kt as initial intensity with no change in strength through LF. Somebody said earlier that Irene reminded them of Ike as far as structure, and couldn't agree more. Nothing right now in the MW or recon data suggests Irene is about to tighten up a really strong core. Big hurricane with widespread significant surge/wind machine as well as bigtime inland heavy rain threat - but probably unable to develop a major hurricane type eyewall/core.

[LakeEffectKing]

NHC now has 90 kt as initial intensity with no change in strength through LF. Somebody said earlier that Irene reminded them of Ike as far as structure, and couldn't agree more. Nothing right now in the MW or recon data suggests Irene is about to tighten up a really strong core. Big hurricane with widespread significant surge/wind machine as well as bigtime inland heavy rain threat - but probably unable to develop a major hurricane type eyewall/core.

I threw out that possibility last night. And with every storm...we collectively learn a little more.....

I wish I could be around for Hurricane forecasting in 100 years!!

[SN_Lover]

Just thought I should throw this out there

2 Days Ago the majority of the models below predicted the hurricane to decay around about now. So all the models are predicting the hurricane to decay even further as of 12UTC.

[LVblizzard]

12z hurricane models are tightly clustered except for the models that mean nothing at this point (BAMS, CLP5, etc.):

[Amped]

I love these new ewall graphics. 40kt plus over a large are.The Jersey coast is somehow a little further east than I thought

[eurojosh]

I think the 12Z GFS seems to be taking it well East of the consensus track...

http://raleighwx.americanwx.com/models/gfs/12zgfs850mbTSLPp06_county042.gif

[wxsmwhrms]

I think the 12Z GFS seems to be taking it well East of the consensus track...

http://raleighwx.ame...6_county042.gif

Any changes in the GFS look to be pretty much at the noise level when comparing to its 00Z and 06Z runs.

[GaWx]

The 0Z Fri Euro per the high resolution site has Irene at 918 mb at 8 PM tonight when it is at 32N, 77W, and at 926 mb at 8PM Sat. evening when it is at 36N, 76W. This is another case where the Euro will almost definitely verify to be ~20-30 mb too strong. What's worse is that we're talking as little as the 24 hour forecast time in this case and it has the lowest pressure of any Irene run to date. This is a continuation of what occurred last season.

It isn't a problem of initializing too low as the 0 hour (as of 0Z 8/26) had it at 942 mb. vs. the actual of 946 mb...i.e., very close.

The Euro has had the lowest pressure ABOVE 30N within the 918-28 mb zone over the last seven runs. That's where the Euro has been especially overdoing pressure drops since last year.

[Riptide]

Good stuff. You've definitely convinced me that this is a huge problem with the euro. I'm sure they are working on it, though.

It's not impossible that it would deepen to 918mb but it's just highly highly unlikely. Also, it could be that Baroclinic interactions influence the pressure of Hurricanes as they move north.

[Snow Man]

The 0Z Fri Euro per the high resolution site has Irene at 918 mb at 8 PM tonight when it is at 32N, 77W, and at 926 mb at 8PM Sat. evening when it is at 36N, 76W. This is another case where the Euro will almost definitely verify to be ~20-30 mb too strong. What's worse is that we're talking as little as the 24 hour forecast time in this case and it has the lowest pressure of any Irene run to date. This is a continuation of what occurred last season.

It isn't a problem of initializing too low as the 0 hour (as of 0Z 8/26) had it at 942 mb. vs. the actual of 946 mb...i.e., very close.

The Euro has had the lowest pressure ABOVE 30N within the 918-28 mb zone over the last seven runs. That's where the Euro has been especially overdoing pressure drops since last year.

Well, this may turn out to be true but I sure like how it sniffed out the track days before the GFS.

[k***]

It's not impossible that it would deepen to 918mb but it's just highly highly unlikely. Also, it could be that Baroclinic interactions influence the pressure of Hurricanes as they move north.

There is zero chance it gets to 918. Zero.

Thanks for the lesson about baroclinic interactions, though.

[Southland Wx]

The 0Z Fri Euro per the high resolution site has Irene at 918 mb at 8 PM tonight when it is at 32N, 77W, and at 926 mb at 8PM Sat. evening when it is at 36N, 76W. This is another case where the Euro will almost definitely verify to be ~20-30 mb too strong. What's worse is that we're talking as little as the 24 hour forecast time in this case and it has the lowest pressure of any Irene run to date. This is a continuation of what occurred last season.

It isn't a problem of initializing too low as the 0 hour (as of 0Z 8/26) had it at 942 mb. vs. the actual of 946 mb...i.e., very close.

The Euro has had the lowest pressure ABOVE 30N within the 918-28 mb zone over the last seven runs. That's where the Euro has been especially overdoing pressure drops since last year.

Well, this may turn out to be true but I sure like how it sniffed out the track days before the GFS.

And at least there is a known bias in play that can be dealt with. Intensity has never been the strong point of models with tropical systems. But nailing track is the biggest thing I think.

I don't know too many people that actually believed those pressures anyway. I interpreted it as the fact that the models predict a hurricane that will be more like a hurricane at an abnormally high latitude than a transitioning ET cyclone. That seemed to be the best indication of what we were seeing on the Euro...not that a 925 mb storm was going to be sitting at a ridiculously high latitude.

[am19psu]

And at least there is a known bias in play that can be dealt with. Intensity has never been the strong point of models with tropical systems. But nailing track is the biggest thing I think.

I don't know too many people that actually believed those pressures anyway. I interpreted it as the fact that the models predict a hurricane that will be more like a hurricane at an abnormally high latitude than a transitioning ET cyclone. That seemed to be the best indication of what we were seeing on the Euro...not that a 925 mb storm was going to be sitting at a ridiculously high latitude.

This. Good post.

[yoda]

Interesting... gained .2 W since 11 AM... probably wobbles. Also now 100 mph

BULLETIN

HURRICANE IRENE INTERMEDIATE ADVISORY NUMBER 25A

NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011

200 PM EDT FRI AUG 26 2011

...IRENE WEAKENS A LITTLE...TROPICAL STORM FORCE WINDS

ARRIVING ALONG THE COAST OF THE CAROLINAS.

SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION

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

LOCATION...31.2N 77.5W

ABOUT 300 MI...480 KM SSW OF CAPE HATTERAS NORTH CAROLINA

MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H

PRESENT MOVEMENT...N OR 360 DEGREES AT 14 MPH...22 KM/H

MINIMUM CENTRAL PRESSURE...951 MB...28.08 INCHES

[Ed Lizard]

As noted by NWS Philly/Mt Holly, mentioned by me, and then mentioned again on TWC last night (and they gave credit to NWS Philly) very favorable jet structure may come in to play to compensate for loss of tropical processes at higher latitudes. And large size suggests slower decrease in strength.

[Amped]

And at least there is a known bias in play that can be dealt with. Intensity has never been the strong point of models with tropical systems. But nailing track is the biggest thing I think.

I don't know too many people that actually believed those pressures anyway. I interpreted it as the fact that the models predict a hurricane that will be more like a hurricane at an abnormally high latitude than a transitioning ET cyclone. That seemed to be the best indication of what we were seeing on the Euro...not that a 925 mb storm was going to be sitting at a ridiculously high latitude.

Yep if a model is always exactly 415.73 miles too far west thats okay, but if it's sometimes 50 miles east and sometimes 50 miles west that makes correcting it hard.

[Cheeznado]

GFDL has come east a bit but still farther west than other models, HWRF holds steady. Both suggest a bit of strengthening before landfall, of course 918 is ridiculous but maybe it can get back down to the 940s.