Hurricane Dean

[HAltschule]

The GFS model...which was dead on right earlier in the season this far out, now has progged what looks to be a major hurricane making landfall along the East Coast. This afternoon's run brings onshore over Charleston, SC.

While the proposed landfall location has changed drastically over the past couple of days, the intensity still looks very significant. The GFS has shown this for about 5 days straight now and 2 days ago had an "Andrew" looking storm striling the Miami/Homestead area. While it is very far out still out, I am making any bets just yet. BTW...the model also shows a 2nd tropical system fast on its heels a few days later.

But persistence of the model runs could make it very interesting in another 11-16 days from now

 

[rdale]

It also had a major east coast system about a week ago that never materialized, and developed a hurricane off of Florida that was supposed to happen this week...

 

[John Peters]

Latest run brings it up the eastern seaboard into Maine/Nova Scotia.

 

[rdale]

It could happen... tomorrow?

 

[Jim Bishop]

The GFS model...which was dead on right earlier in the season this far out

I recall it advertising a couple different times a hurricane over the Eastern Atlantic in the past few weeks that never materialized. When was it dead on right?

I will say this. The GFS has been REMARKABLY concistant for (I believe) five days now in advertising a tropical system to develop this weekend over the Eastern Atlantic. Furthermore it has had support from the Canadian for a couple days as well as the GFS Ensemble, and today NOGAPS and the UKMET are at least advertising lowered pressures. The Euro jumped on board too.

This will be a home run for the GFS if a tropical system does indeed develop this weekend.

 

[Bob Schafer]

It's interesting, yeah. Today's 18Z run places it E of FL/GA at 252 hours (070820/06Z), and then it skirts the E coast to become sub-trop.

MSLP only 999mb. How is GFS at trop storm pressures? Anyway, SST's are pushing 30C in that area now, so depending on shear we could well see something deeper than that.... if we get anything at all, LOL.

 

[HAltschule]

I recall it advertising a couple different times a hurricane over the Eastern Atlantic in the past few weeks that never materialized. When was it dead on right?

http://www.stormtrack.org/forum/showthread.php?t=12564

 

[Jim Leonard]

I think the system the models are keying on is the complex low and convection thats about to come off the African coast at the moment, we'll have to see if the is the real thing. The center is down at about 9N so it should come off the coast and develop further.

 

[Doug_Kiesling]

It could happen... tomorrow?

BAHAHAHAHA yeah, it could happen... Just like the major system that the GFDL had for a system that was suppose to hit Central America over a week ago.

I seem to recall the hype of May 2006 that last year was going to be the "SEASON OF DOOM BUT WATCH US TO STAY ALIVE..." and the "GLOBAL WARMING IS MAKING HURRICANES BIGGER...

Then what happened? Um, not much hit the United States and it was pretty much a normal hurricane season with some storms that hit the fish and shipping lanes.

Yes the latest computer models show something brewing but how many times has SPC Day 1 said something was brewing and then it turned out to be a bust? I'm not buying the models this year since they have been way off on a lot of the forecasts in general.

 

[Stuart Robinson]

For example.... look at the current CMC model run

Big Hurricane in the GOM within the next 5 days...

http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2007081000&field=Sea+Level+Pressure&hour=Animation

 

[Jim Bishop]

BAHAHAHAHA yeah, it could happen... Just like the major system that the GFDL had for a system that was suppose to hit Central America over a week ago.

I seem to recall the hype of May 2006 that last year was going to be the "SEASON OF DOOM BUT WATCH US TO STAY ALIVE..." and the "GLOBAL WARMING IS MAKING HURRICANES BIGGER...

Then what happened? Um, not much hit the United States and it was pretty much a normal hurricane season with some storms that hit the fish and shipping lanes.

Yes the latest computer models show something brewing but how many times has SPC Day 1 said something was brewing and then it turned out to be a bust? I'm not buying the models this year since they have been way off on a lot of the forecasts in general.

Last year El Nino developed around this time, increasing the wind shear and effectively dampening the season. (I agree there was a lot of over hype coming off the 2005 season).

NOW La Nina is developing. Huge difference. Plus, the Indian monsoon season has been incredible, which is currently helping the African wave train.

As far as the computer models, having the American, European & Canadian global models concistently forecast tropical systems is, at the very least, these models tellings us the hurricane season about to get going in the next week or so.

This year is quite interesting because most people simply do not believe this hurricane season will amount to anything. Let's see what people think in about one month.

Cheers

 

[Jim Bishop]

http://www.stormtrack.org/forum/showthread.php?t=12564

I wasn't aware the GFS forecast that so far in advance, wow. Gives me more reason to believe it's Eastern Atlantic wave development coming up here in the next few days.

 

[HAltschule]

I wasn't aware the GFS forecast that so far in advance, wow. Gives me more reason to believe it's Eastern Atlantic wave development coming up here in the next few days.

Yes...the GFS Operational model located at this link goes out to 360 hours. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/

Incidentally, this mornings 6z run still has a MAJOR hurricane approaching the bahamas and East Coast Florida..then taking a hook north and out to sea BEFORE making landfall. Of course lots will change...but it's still interesting to see the GFS consistency.

 

[Bob Schafer]

...this mornings 6z run still has a MAJOR hurricane approaching the bahamas and East Coast Florida

Howie, with all due respect, you keep saying "MAJOR" hurricane, but the (same) 6Z GFS run this morning progs a central pressure in the 980's at 288 hours:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_ten_288l.gif

That, of course, would be unlikely to be a major 'cane. Do you have some other reason to believe cat3 or higher should be expected attm?

 

[cdcollura]

Good day all,

One MAJOR thing to consider with the models is the SCALE of an "expected" weather system.

Jet-Stream flow and troughs are very large (sometimes a trough is larger than half the USA). These are large scale patterns.

Smaller lows, such as MCV's and MCS type features are on the MEDIUM to small scale (mesoscale).

Things like dust devils, waterspouts, and tornadoes are of the microscale (smallest).

My point is that the smaller the scale, the more chaotic, complicated, and difficult to forecast / model it becomes.

Fortunately, tornadoes are produced by larger scale systems that they depend on (such as a trough), so forecasting them is "do-able" to some extent.

Hurricanes fall into the medium scale, and about 90% of the time, the models do not handle them well, with the GFS being the most successful, if you wish to call it "successful" for tropical systems.

Remember the storm Ernesto last year in 2006, how the models handle that one?

They (the models) had the storm OVER CUBA, and going from a 40 MPH storm to a 80-95 MPH hurricane hitting Florida. We (or most of us) know hurricanes do not strengthen over land, let alone mountains! Sure enough, with a hurricane warning, closures, and all the "hassles" uderway in FL, the storm came in as a 30 MPH depression.

Intensity / formation model forcasts for tropical systems are pretty much junk most of the time. Track forecasts, governed by steering flow (such as a trough on the east US coast causing a storm to recurve) are henerally MUCH more reliable.