Hurricane Dean

[HAltschule]

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?

Well, yes. Let me first clarify that if this does in indeed develop, this is my reasoning for a "Major" labelling. Now that we have a reoccurring system on numerous model runs, it has been my experience over the years that isobaric patterns and pressures on the GFS are almost always underdone and not idicative of the true strength of the system. All of the CAT 3+ storms that I have seen on the GFS have had similar presentations on the gridsand they have been Major Hurricanes. This is why I think it will be a major hurricane if it does indeed form.

 

[Jim Leonard]

One thing to remember that if you have a significant tropical showing up on most models in mid-August to mid-September and their holding on to it run to run through the ten day forecast time coming across from the eastern atlantic, also showing several isobars around it one could assume it will be a major hurricane. The models show little or no shear to deny major intensification. The sst's will be more than warm enough especially when any developed storm gets past 60W. Those two perameters should work together to make a storm in my opinion reach an intensity of 950Mb or lower if it comes to a position north of Puerto Rico like the gfs is indicating today.

 

[HAltschule]

One thing to remember that if you have a significant tropical showing up on most models in mid-August to mid-September and their holding on to it run to run through the ten day forecast time coming across from the eastern atlantic, also showing several isobars around it one could assume it will be a major hurricane. The models show little or no shear to deny major intensification. The sst's will be more than warm enough especially when any developed storm gets past 60W. Those two perameters should work together to make a storm in my opinion reach an intensity of 950Mb or lower if it comes to a position north of Puerto Rico like the gfs is indicating today.

Indeed. One thing very favorable are the very warm, so far undisturbed SST's.

 

[Doug_Kiesling]

Well if the model runs hold together after several days worth of runs, and something shows up on the sat that looks decent, then I might get excited and pay attention to them but right now, I'm really not trusting them 10 days out or even 5 days out.

Just look at the models from yesterday for todays setup in the upper midwest compaired to what is really happening right now. Even the Day1 has changed so much that I'm sitting at home thanking the lord that I did not get suckered into driving 300 miles to find out it moved another 250 miles west.

I just don't trust the models at all that far out and nobody can predict the future.

 

[HAltschule]

Hi Doug,

I do understand what you are saying and I also am somewhat skeptical on mid-range and long-range forecasts too. That said, the models have shown this monster for about 6 days now and that kind of consistency tends to make these events (or other synoptic scale events) more believable. Obviously if a storm occurred in another week, a 250 mile difference between the model forecast NOW and the verification position THEN doesn't mean diddly. The fact that it got it right within a 1000 square mile area would be impressive enough.

I don't think it's reasonable to compare the GFS model run's accuracy over a mid-range period to the SWOD1 being 250 miles off. Mesoscale processes affect the severe potential very differently than synoptic scale procceses do for the GFS runs.

 

[SteveCarter]

Normally I would just forget about any forecasts this far out, BUT like Jim L. said.....any time you get a solid system moving off the African coast in August/September, there COULD be something to look out for. The local weather forecast on T.V. tonight said to keep an eye on this system, or the one behind it. They said something about dry air being pulled into the first one, but still, it could be a major system. We'll see. Here in south Carolina, we desperately need the rain, and I'm desperately in need of "chasing" something! LOL

 

[Gene Moore]

Normally I would just forget about any forecasts this far out, BUT like Jim L. said.....any time you get a solid system moving off the African coast in August/September, there COULD be something to look out for.

I think this statement about the African coast is the key. Many of the phantom storms already forecast this season and one huge one last season came out of nothing real at the surface. At least this time there is a real storm now moving in the ITCZ east of Africa. I can only speculate it's this storm complex that the GFS is working its voodoo on. It makes more sense at this time to watch the actual cloud mass for development than get too wound up over the model. Perhaps one of the reasons it jumped on it so soon was the large size when it came off the coast, but this morning (afternoon there) it's not nearly so big.

The easterlies are strong this year but the ITCZ appears to be a bit further south than usual, thus leading the easterly waves into southern Mexico. There have been numerous convective outbursts that seem to die south of Cuba....in fact there is a very large one this mornig. Most of these don't make it into the Gulf of Mexico, the trajectory just seems wrong....any thoughts on that?

Gene

 

[Justin Bailey]

Its been so dry all summer up here in Tennessee, especially this month, that our forcasters in Nashville arealready talking about this system! we really could use the rain from the remnants of some sort of tropical system to help with the drought!

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[FONT=Courier New, Courier, mono]FORECAST DISCUSSIONNATIONAL WEATHER SERVICE NASHVILLE TN253 AM CDT SAT AUG 11 2007.DISCUSSION................BEYOND FRI...LOOKS LIKE THE SLGT CHC OF RAIN WILL CONTINUE FOR SAT-MONAS LIGHT SELY/SLY FLOW CONTINUES. BEYOND MON...GFS BRINGS A SFCLOW OUT OF THE TROPICS AND TURNS IT NWD. PREVIOUS RUN OF THE GFSBROUGHT IT THROUGH THE CARIBBEAN JUST SOUTH OF CUBA. CURRENT RUNBRINGS IT THROUGH THE SWRN ATLANTIC JUST NORTH AND EAST OF THE BAHAMAS.WELL SEE.[/FONT]

 

[HAltschule]

The local weather forecast on T.V. tonight said to keep an eye on this system, or the one behind it.

They must read Stormtrack

 

[HAltschule]

A Sunday morning check of models shows the GFS bringing the system into Mexico in around 9 days, the Candian Model bringing it near St. Thomas and the northern V.I.'s in 120-144 hours. The GFDL has listed the system as invest 90i and has a CAT 3 hurricane knocking on the door of the northern and central Virgin Island in 126 hours. The HWRF is almost identical to the GFDL and also brings a CAT 3 hurricane to the same location in 126 hours.

I am very impressed with all of the model consistency this far out. All of this makes me 100% believe there will be a CAT 3 or higher hurricane in the Tropical Atlantic or Carribean in a few days. Next question is whether it hooks just to the north and heads toward FL or does it stay west (like the GFS says) and hit Houston, TX?

 

[Jim Leonard]

My thinking this morning that this system will probably be a compact "Charley" type hurricane size wise, as it approaches the Lesser Antilles later this coming week. It appears now there will be a solid zonal ridge across the atlantic this coming week or so, remember "Emily" 2005. The gfs track across the Caribbean into the southern GOM looks reasonable. If the storm were to reach the western Caribbean the warm ridge over the U.S. should keep it on a westerly heading.

 

[Stuart Robinson]

I am sure that by now you will all know that Tropical Storm DEAN has formed...

 

[Matthew Crowther]

TS Dean

We now have Dean- Position and track are now shifted south- this really puts Puerto Rico under the gun- the 06Z HWRF has the storm as a 920!!! mb monster just south of the island

 

[John Peters]

We now have Dean- Position and track are now shifted south- this really puts Puerto Rico under the gun- the 06Z HWRF has the storm as a 920!!! mb monster just south of the island

where are you viewing the most recent HWRF run?


Looks like today's GFS run still wants to bring the storm north toward the Carolinas..

 

[Terry Tyler]

i know it...

sure hope it goes into the gulf of mexico...

aint never seen a hurricane...and i got a freind down in columbia mississippi...she got tore up when katrina hit, and already said if a cane is coming i can go down there and use the house as a place to start from instead of coming all the way from mantachie...