Tropical depression 9(unoffical forecast one...)

[Matt-hurricanewatcher]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.


Tropical depression 9
7pm pst/10pm est
8-4-2005

First cape verde depression of the season forms....


Over the last 3 hours, the LLC has become better defined. With now a central core of convection forming right over it. Earlier it was mostly a broad LLC. With its mid level discoupled to the west. Overall tonight everything is now moving around one center.

Data out of Cimss, shows that this system has a strong upper level high. With wind shear vaules of 5 knots near the center. While faning out to 20 knots near the edges. Which is almost a perfect pattern for tropical cyclone development. A outflow Jet to the northwest around 25 north/40 west, has formed with 40 knot shear. In which case if the system can stay south of 15 to 17 north should start enhancing outflow even more. Some time between Friday afternoon or Saturday morning. The outflow set up is almost perfect.

What is causing this system not to oreganize is the SAL=Saharan air layer. Which is very thick to the northeast of the center. In even to the west is only favable enough to allow this to hold its own. If it was not for the perfect outflow pattern/overall oreganizion of the cyclone. The seasurface temperatures/Tchp which are at record levels with perfect outflow(Low shear) should help to off set some of this effect. Also the SAL will not be quite as unfavable as it moves westward.

In the SST/TCHP should only get better over time. With low shear expected for the cyclone. So a tropical storm should be expect with an the next 12 hours. Also the ship model make this system a tropical storm by 24 hours. Then a hurricane by 72 hours. In which might be a little fast with the hurricane.

Track

The models show that Harveys, should pull out over the next 48 hours. The hurricane/Global models been having a hard time this year with forecasting to far to the right over this area. In it looks to be true for this system. The Hurricane models have shifted to the west over the last 12 hours. The Gfs is showing a fairly strong high to the north for the next 30 hours. But it shows a 290 to 300 degree movement or west-northwest over that time frame. The Gfs has also shifted greatly to the left. The 18z Gfdl shows a west-northwest movement going just north of the Islands at 126 hours. It has also shifted left with its lastest 00z plots a few degrees. Gfs 00z is slower making it north of the islands by 138 hours. Then it turns it more to the west around 138 to 144 hours. In which would take a track close to Frances of last year.


But you have to remember that the ridge to the north will likely be stronger then shown. In the models are moving leftward with each new run. So I'm keeping it on a westward track for the next 24 to 36 hours fellowed by a west-northwest track. This system will likely be a threat to the northeast leeward islands by 128 to 136 hours. I'm thinking it will skim the northern end making its landfall around 18.5/62 west. Then moving into Purto rica by 24 hours after. There is a chance for a hurricane.


On quickscats there is a area of 25 to 30 knot winds. In because of the oreganizion. I'm setting it at 30 knots...


Now 30 knots
6 30 knots
12 35 knots
24 35 knots
36 45 knots
48 50 knots
60 55 knots
72 60 knots
84 65 knots
96 65 knots
108 70 knots
120 80 knots
136 50 knots landfall on purto rica.

Forecaster Matthew

[Matt-hurricanewatcher]

At this minute it could go both ways...

[rainstorm]

sounds like a good forecast matthew

[jkt21787]

I agree, good forecast, though I don't think that PR (if it landfalls there) will weaken it by 30kts unless it stalls or slows significantly. Otherwise very good.

[Derek Ortt]

don't we need a track so we know where the storm will be going, letting everyone know where the 80KT winds will impact?

[Swimdude]

a PR hit..? Doesn't seem likely... I guess that's just me... All models show it curving out, don't they?

[jkt21787]

a PR hit..? Doesn't seem likely... I guess that's just me... All models show it curving out, don't they?

no, far from it. Models are shifting west and even at this stage don't showa definite recurve since the ridge could easily allow a more westward motion after 120 hours. Many pros are saying this has real potential to be a land threat, including possibly on the U.S.

[fci]

I'm glad that we are like 5 days away from the islands because the model shifting makes it more and more a concern for the SE and FL.
We have a long, anxious time ahead learning where this thing will go and I know there will be ebbs and flows, wobbles and shifts that will add to the uncertainty as the days go by.
I'm glad that there is S2K to monitor this through its genesis and eventual path!

[weatherwindow]

while it may not be ultimately significant, the nws/mia and nws/mlb are both highliting ridging with deep easterly/east-southeasterly flow in the tues-sat time frame. now what impact that will have on the track remains to be seen. i would, however, be a lot more comfortable if #9 gained a couple of degrees of latitude in the near future ........rich

[WindRunner]

The ridge may be strengthening, but it's not going to put it into Puerto Rico. Maybe 200nm north IMO.

[ThunderMate]

This will probably be a Carolina strm and follow her sister Isabel's track due to the ridge being pushed out some by Harvey and allowing a curve straight into the SE coast most likely NC and VA.

[Jim Cantore]

if it survives it MIGHT if it doesn't go out to sea