Irma -- Updated 9/11

Yes I know about Irma.

Yes, I am following it.

No, I don't know where it will be in two weeks, but you will be the first person I tell when I do.

:-D


did they officially name it?




11:00 am this morning, but we have been seeing it for a couple of days in the models.


oh-a new system. (ugh!)  the one off the east coast that just past is what I was thinking of.


I think that one never developed to the point of being named. It was thought it might and had it it would have been Irma. But since it did not the next one because Irma. 


I see Irma has exceeded previous intensity expectations by quickly jumping to a Cat 3. Some models show it may become  a Cat 5.

The late model tracks show it may impact us.



At its current rate, when might it be a threat to the East Coast? Is Sept10-12 range about right?



conandrob240 said:

At its current rate, when might it be a threat to the East Coast? Is Sept10-12 range about right?

Likely.

But long range forecasts, 10 days, leave much to be desired. Also, long range intensities. 

Its the five day forecasts one needs to pay attention to. 

I watch them because they're interesting.


There are two other "disturbances" out there now as well, one in the eastern Atlantic and one in the Gulf of Mexico.  Low chances of becoming a cyclone.


it's been quiet for a few years now. we're due.  LOL 


http://www.nhc.noaa.gov/refresh/graphics_at1+shtml/145426.shtml?cone


This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow). The orange circle indicates the current position of the center of the tropical cyclone. The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC's forecast intensity for that time:  D: Tropical Depression – wind speed less than 39 MPH S: Tropical Storm – wind speed between 39 MPH and 73 MPH H: Hurricane – wind speed between 74 MPH and 110 MPH M: Major Hurricane – wind speed greater than 110 MPH

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast "cone", the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above.

Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt50 kt, and 64 kt thresholds.


cone graphic


Gov Malloy in CT jumping the shark on this one.  I think he is seeing good photo ops in light of the attention being paid to Houston.



Way, way early to panic on this one.  The most likely track keeps it out to sea, but it really at this point could go anywhere from the Leeward Islands to Cape Cod.

Irma is a big, bad storm.  There will be excessive coverage and early overreaction. It is not, however, an anamalous storm.  It bears watching.

Were it to hit the east coast, Sept 10 - 15 would be best guess right now.  Earlier for the Caribbean or Gulf, or Florida. With current forecast track and sea temps, cat 5 is possible but 4 more likely. 


Latest run of the GFS.  Note the wide variety of 10-day (240 hour) locations.


This chart takes all the models and creates a mean plot (the bright red line). Note that this plot, at this time, keeps Irma safely offshore.  But again I want to emphasize how far out in time this is and the corresponding lack of any sort of forecast certainty in that time frame.


interesting. All have it sparing FL, many the Caribbean. Looks like a very targeted Carolinas to Massachusetts hit pattern. Whilevthats wide, that's pretty solid agreement this far out, no?



conandrob240 said:

interesting. All have it sparing FL, many the Caribbean. Looks like a very targeted Carolinas to Massachusetts hit pattern. Whilevthats wide, that's pretty solid agreement this far out, no?

It is not bad, but they will flop around as a group as the data changes.


I thought I read somewhere that Irma has started further east than any other storm.

Is that correct, and if so, wouldn't that make it at least a bit of an "anomalous" storm?


Is it just me or were the A-G storms duds?  I don't remember hearing anything about any of them.


Is it time for New Jersey Transit to shut down yet? 



drummerboy said:

I thought I read somewhere that Irma has started further east than any other storm.

Is that correct, and if so, wouldn't that make it at least a bit of an "anomalous" storm?

The easternmost hurricane to form, according to Wikipedia, was Vince in 2005, at 18.9 degrees west. Irma was about 15 degrees farther west when it reached hurricane strength.

If by "started" you mean the tropical wave, I suppose the magnitude of anomaly would depend on how much farther east it formed compared with typical Cape Verde storm systems. Given that the islands are only 350 miles off the African coast, I don't see a lot of room, oceanwise, for a noteworthy difference.


Same chart, 12 hours later.  

This is why we are sceptical about the accuracy of 240 hour forecasts.


Another representation from 8/31 at 8pm.


So Wyoming is safe, then.


Wow, yeah. Completely different trajectory. I'm in FL for next 10 days so concerned about here (mostky about getting home for obligations on 9/11 and 9/12) and all the patio furniture I left out in NJ. We'll see who "wins"

max_weisenfeld said:

Same chart, 12 hours later.  

This is why we are sceptical about the accuracy of 240 hour forecasts.



Things are fairly status quo this morning with Irma.  The storm iss over a mildly warm part of the ocean, is at the moment a cat 3, very compact but with an indistinct eye. 

In a few days the storm will move over warmer water, move more northwest, and strengthen.  Unless you are on a boat, for the next five days Irma will not have any effect on you.

If Irma were to make landfall on the continental USA, it would most likely be between Sept 10 and 12.


I know it is too early for accurate predictions, but can you give me a guesstimate of if/when Puerto Rico will be hit, and how bad it might be?


The long range tracks have converged. Which is usually not the case, as seen in my previous above posting.



BG9 said:

The long range tracks have converged. Which is usually not the case, as seen in my previous above posting.

No, they have not.

This is only one model, the GFS, and these are not nearly all the tracks.

This is the current GFS run showing more of the components:


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