Major Hurricane Irma

[hudsonvalley21]

2 minutes ago, donsutherland1 said:

Thanks. My five-year-old and I will likely watch the storm from afar. He's already had some exposure to the computer models.

He is fortunate to be learning from a guy with some experience.  Great to hear. 

[donsutherland1]

1 minute ago, psv88 said:

From "afar". Wishful thinking Don!

Given the uncertainty, I did qualify it with "likely." We'll see. I'm more concerned about my sister and her family who reside on the South Shore of Long Island.

[Casualbrain]

If you look at the water vapor loop - a bit of a clue as to why the track seems odd, and what the WAR is doing:
http://tinypic.com/r/2uib23p/9

 

 

[donsutherland1]

Just now, hudsonvalley21 said:

He is fortunate to be learning from a guy with some experience.  Great to hear. 

Thanks. 

[USCG RS]

If you look at the water vapor loop - a bit of a clue as to why the track seems odd, and what the WAR is doing:
http://tinypic.com/r/2uib23p/9

 

 

http://www.ssd.noaa.gov/goes/east/catl/h5-loop-wv.html

That last frame looks pretty healthy tbh. New convection flaring, while outflow reestablishing itself.

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[Hazey]

Irma looks like it going to take off again. Seems to be pulsing in its strengthening. Gains some...looses a bit. Like a person blowing then taking a breath and blowing stronger again. Fascinating to watch it evolve.

[Jackstraw]

  The TUTT to her NW is modeled to dissipate.  Around that time the storm starts to get a more northward component.   The models have been delaying the decay of that TUTT with each run.  I'm not saying that is a major player in the steering but the longer that thing hangs around I think the more west the storm will go.  Might be a good barometer to watch as time progresses.  Plus the ULL coming in from the NE is really going to help evacuate the storm Whenever it starts to round the bend.  Might be why some of the models are strengthening it a little more.  It's going through some growing pains right now, possible ERC, trying to expand it's wind field, a little SE shear, some sinking air on it's southern flank.  The outflow has come and gone.  Mind you it's obviously sufficient for the intensity it's at but there are no real good outflow channels established yet, especially to the south.   I'm not buying into any model solution as of yet other than it's going to make it to 70W.  It's been a little lost in the conversation of late but the evolution of the ridge out west is going to be just as important as the other players.  When models start playing with cutoffs this far out it's been my experience that's exactly what they are doing, playing with them.  The few storms I can remember that were either forecast or did interact with a cutoff over the eastern conus around LF seem to be the ones that the models have the most issue with.  And rightfully so as the details are much more subtle in those cases than a typical trof swinging through. Models also can get the strength of a ridge with skill but the axis or orientation of ridges they seem to have trouble with out beyond even 72 hours.  The axis of these ridges is also going to be important if the atmosphere ends up in the predicament the models are forecasting 8-9 days out.  

It's also been my experience that the models have an east biased with fairly strong storms under strengthening ridges in the Atlantic.  I wouldn't be surprised to see a few more runs go west.  That doesn't mean the storm wont lift out. Still way to early to say it's gonna hit the conus just as much as it's way to early to tell the conus it's gonna hit

Just my 2 cents, but at this range I think my amateur forecasting skill is about on par with TABD lol.

 

[CaWx]

Curious, what model is the TABD? How much money went into this model? Whatever it is, I will draw storm paths for half the price. 

[TriPol]

I'm beginning to see some interaction with Irma and PR/Hispaniola predicted by the models. Irene had some brief interaction with Hispaniola which weakened her down from a Category 2 to a 1. Once she made the turn North and entered the Bahamas, however; she regained her strength and became a Category 3. Irene skirted the Carolina outer banks (just as Gloria did) and hit Long Island. The difference is the models are showing that something is going to capture Irma and cause her to give a left hook and retrograde west. It will be interesting to see how strong the High Pressure to Irma's North and East is and if the trough captures her or kicks her OTS.

[bdgwx]

13 minutes ago, CaWx said:

Curious, what model is the TABD? How much money went into this model? Whatever it is, I will draw storm paths for half the price. 

It's one of the beta advection trajectory models similar to BAM. There are 3 variants S-shallow, M-medium, and D-deep layer steering flow depths. So TABD is the deep layer variation. There are inferences that can be made by looking at the spread between the variants and that forecasters use them in that manner more so than in making a track forecast from what I understand. I don't really know much about them other than that and I usually don't ever pay attention to them either. I did notice the odd track though. I do have some thoughts on why it yields that staggered track, but since I can't back it up with facts so I'll punt on presenting my thoughts here.

[pazzo83]

2 hours ago, Coach McGuirk said:

What about Hurricane Hugo?  That was a cat 4 that went straight into South Carolina back in 1989?

Hugo actually hit PR.

[TriPol]

Out to hour 18, GFS has Irma weaker than it has had it in the past few runs at 974. As Jackstraw mentioned earlier, Irma has had some growing pains that the GFS did not predict. It will be interesting to see what impact this has on her track.

[MJO812]

Out to 48 hours

10 mb weaker and in the same position as 18z

[NJwx85]

6 minutes ago, TriPol said:

Out to hour 18, GFS has Irma weaker than it has had it in the past few runs at 974. As Jackstraw mentioned earlier, Irma has had some growing pains that the GFS did not predict. It will be interesting to see what impact this has on her track.

This was actually pretty well forecasted. Strengthening should begin by Monday and the NHC forecast reflects this.

[NJwx85]

1 minute ago, Snow88 said:

Out to 48 hours

10 mb weaker and in the same position as 18z

The SLP has very little value. Track is the key here.

[TriPol]

Hour 54, Irma is just a touch south and west of its 18z position.

[yoda]

Going to be close for the northern most islands at 72

[NortheastPAWx]

I think I'd find it notable to see that the NHC likely has this passing over 70W before 25N.

[LovintheWhiteFluff]

Through 72 @500 it looks like 18z. 

[DopplerWx]

yea a bit further south at 78, islands def getting closer to Irma this run.

[TriPol]

Out to 84, Irma looks like she's going through some deepening, and definitely looks like she's going to hit the northern islands.

[NJwx85]

Very little change through day 4. A slight tick SW, that's it.

[yoda]

Northern most Antilles Islands (Saint Kitts/Barbuda/Antigua) look to be hit head on at 90

[MattPetrulli]

00z GFS a tad to the SW.

[LovintheWhiteFluff]

slight changes with the ULL @ 90. It's not digging as much. 

[Hazey]

As noted. Close swipe to Antigua. If I lived there I'd be holding my breath.

[TriPol]

Out to 96, may just brush PR. Might start seeing some TS watches issued tomorrow or Monday.

[ncskywarn]

Between hours 90-96 Still moving more between W & WNW as opposed to 18Z same time frame movement of between WNW & NW.

[Hoosier]

3 minutes ago, Hazey said:

As noted. Close swipe to Antigua. If I lived there I'd be holding my breath.

Certainly a nod toward what the ECMWF has been advertising as far as the islands.

[Hazey]

Let's see if it bests it's previous low pressure in the previous run.