ATL: ISAAC - Post-Tropical - Discussion

[Blinhart]

All I know is a huge feeder band is about to smack Miami with some serious rain!!

really don't think that is a feeder band.

[ozonepete]

There is no eye and won't be until Sunday. RGB and IR satellite show it's beginning to ingest dry air from subsiding air coming down the mountain slopes of Hispaniola, i.e. convection is collapsing on the northern side. The center is also opening up on the southeastern side. While this is expected due to the very mountainus terrain of hispaniola and eastern Cuba, I really feel that Isaac will bust loose on sunday as it moves off the northern coast of Cuba. With such an impressive outflow mechanism due to an upper level anti-cyclone (that isn't expected to dissipate) it should do a really impressive RI on sunday. But I really don't see where everyone is expecting a TC crossing this area to intensify(?!) before then.

[Blinhart]

I'm starting to think that this slower movement, will have a major effect in the future path of Isaac. The longer it takes to move North, I feel it will take a further Western Path. I'm starting to think that the Euro from a couple days ago that showed a Sabine Pass landing on Thursday might be more than accurate.

[HurricaneAndrew92]

There is no eye and won't be until Sunday. RGB and IR satellite show it's beginning to ingest dry air from subsiding air coming down the mountain slopes of Hispaniola, i.e. convection is collapsing on the northern side. The center is also opening up on the southeastern side. While this is expected due to the very mountainus terrain of hispaniola and eastern Cuba, I really feel that Isaac will bust loose on sunday as it moves off the northern coast of Cuba. With such an impressive outflow mechanism due to an upper level anti-cyclone (that isn't expected to dissipate) it should do a really impressive RI on sunday. But I really don't see where everyone is expecting a TC crossing this area to intensify(?!)

I'm an amateur,but I say this skims east Cuba tommorow morning.

[OzCycloneChaserTrav]

This mornings ECMWF run ( 5am Australian eastern standard time ) sums up Isaac"s Wind field perfectly I beleive. The run showed the most intense part of the Windfield being north east of the main centre, and going by latest satellite that seems to be where most of the convection is. You could safely assume this is where the most intense winds would be.

Euro run this morning would be scaring alot of people in Florida and the southern gulf coast. Unless Isaac becomes a strong category 3+ Hurricane, I can't see him having a perfect 360 Windfield. This could be possible just before landfall on the southern gulf coast, however the main threat to Florida will probably be the massive Windfield to the NE of the system as it just passes west of Florida.

If he then gets into the gulf and doesn't hug the Florida coastline and gets into open water then obviously we will see some fast strengthening of the system. So who knows how strong he could get before landfall. If he does become a significant hurricane before landfall, then I would expect that his Windfield would become much better concentric, rather then being mostly
On that NE quadrant.

Anyway that's just my quick take on the general ECMWF model run from this morning. It hasn't really changed to much over the last 3 days.

All I know is that if in Australia, if we had a tropical cyclone that got into the coral sea for 2 - 2.5 days with warm water above 26.5c, great atmospheric conditions for development and limited dry air, then on our scale we could see a Tropical cyclone go from a depression, into a category 3 cyclone in that time period.

Cheers.

This 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.

[jinftl]

NWS Miami Discussion from late this PM:

ALL EYES THEN TURN TO TROPICAL STORM ISAAC. ISAAC HAS BEGUN ITS
NORTHWEST TURN AND WILL MOVE OVER HISPANIOLA AND TOWARDS EASTERN
CUBA OVERNIGHT. ALL MODEL GUIDANCE HAS SHIFTED SIGNIFICANTLY TO
THE EAST FROM RUNS YESTERDAY. THE ECMWF IS THE FURTHEST
WEST...WITH THE STORM MOVING CLOSE TO THE CURRENT NHC OFFICIAL
FORECAST TRACK. THE OTHER MODELS NOW BRING THE STORM INTO THE
MIDDLE KEYS OR SOUTH FLORIDA. IN ADDITION...MOST OF THE MODELS
SHOW LITTLE INTERACTION WITH CUBA. THIS COULD BE VERY SIGNIFICANT
FOR SOUTH FLORIDA...BECAUSE THE STORM WOULD BE ABLE TO SPEND MUCH
MORE TIME OVER WATER. LOOKING AT THE GLOBAL MODELS AND HURRICANE
MODELS...THEY WOULD BE INDICATING A HURRICANE POSSIBLY MOVING
INTO THE MIDDLE KEYS OR SOUTH FLORIDA SUNDAY EVENING. THIS IS ALSO
SOMEWHAT FASTER THAN PREVIOUS RUNS. SO THERE IS A LOT MORE
UNCERTAINTY FOR SOUTH FLORIDA. THIS IS ONLY ONE SUITE OF MODEL
RUNS...BUT THE THREAT TO SOUTH FLORIDA LOOKS TO BE INCREASING.

[HurricaneAndrew92]

To get a discussion going, who buys the eastern models and who buys the nhc track.

[MidnightRain]

To get a discussion going, who buys the eastern models and who buys the nhc track.

There's really not THAT much of a difference.

[JamesCaneTracker]

Just wondering why some people are acting like this is going to make landfall any time now? Based on it's current position and speed it's still about 100 miles off shore which would mean there is still about 10 hours before landfall...

[LaBreeze]

I'm starting to think that this slower movement, will have a major effect in the future path of Isaac. The longer it takes to move North, I feel it will take a further Western Path. I'm starting to think that the Euro from a couple days ago that showed a Sabine Pass landing on Thursday might be more than accurate.

Not good for us then Blinhart. I tend to think you may be right - but I'm hoping we are so wrong.

[Blinhart]

I'm starting to think that this slower movement, will have a major effect in the future path of Isaac. The longer it takes to move North, I feel it will take a further Western Path. I'm starting to think that the Euro from a couple days ago that showed a Sabine Pass landing on Thursday might be more than accurate.

Not good for us then Blinhart. I tend to think you may be right - but I'm hoping we are so wrong.

I've been trying to be understanding of what is going on, but sometimes I have to follow my gut. I'm just thinking that there has been a lot of errors in forecast forever, and the experts even suggest they really don't know everything about Hurricanes.

[ozonepete]

To get a discussion going, who buys the eastern models and who buys the nhc track.

as is usualy the case with these types of scenarios, all you can do is watch. We can't really tell how much the Atlantic ridge will strengthen over the next two days nor how much the western ridge will or how deep the trough will get in the east. The only clues we get that are worth bothering about are the model output from the best models, which have done quite well this season so far in really difficult forecast problems. I really wouldn't say much until we see the 00Z GFS output which will come out around 11:30PM tonught. I'm quite curious if it will shift east but really couldn't tell you what I think it will do. I wouldn't be surprised if it ran Isaac up the west, middle or east coast of Florida, but really don't think anywhere west of the Florida panhandle is in play. JMHO.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[fci]

I'm starting to think that this slower movement, will have a major effect in the future path of Isaac. The longer it takes to move North, I feel it will take a further Western Path. I'm starting to think that the Euro from a couple days ago that showed a Sabine Pass landing on Thursday might be more than accurate.

I think the longer it takes, the stronger it gets and the further north that he goes.
The path across the Lower Key, clipping the SW tip and then into Eastern GOM with second landfall (if it actually makes a first on SW FL) in the Panhandle, FL/AL border area is what has been pretty consistently forecast and makes the most sense to me.
I just don't see a reason for the further western path.
Can you explain what draws you to that conclusion?

[jeff]

I think the confusion here is also the fact there are watches outside the cone. The cone is confusing, as it is simply a line with the rate of error in miles for the center on either side at that particular timeframe- such as 12, 24, 36, 48, hours, etc. That means that if the center (eye) of the storm were to travel to the outer line of the cone, etc. then those outside the cone would see the effects of hurricane force winds, possibly or tropical storm force, etc. Whatever the storm happens to be at that point. I hope this makes sense.
An example, here in Palm Beach county we are actaully just outside the cone yet we are already under a tropical storm watch.

Bryan Norcross did a good job on TWC explaining that TS force winds would basically extend all acrossthe entire peninsula of FL if it followed the GFS track, not just affecting "the cone"

The "forecast" cone has nothing to do with the area of TS or Hurricane force winds. The cone does not show where and how severe impacts will be only the possible error out in time of the forecast track.

[Blinhart]

I'm starting to think that this slower movement, will have a major effect in the future path of Isaac. The longer it takes to move North, I feel it will take a further Western Path. I'm starting to think that the Euro from a couple days ago that showed a Sabine Pass landing on Thursday might be more than accurate.

I think the longer it takes, the stronger it gets and the further north that he goes.
The path across the Lower Key, clipping the SW tip and then into Eastern GOM with second landfall (if it actually makes a first on SW FL) in the Panhandle, FL/AL border area is what has been pretty consistently forecast and makes the most sense to me.
I just don't see a reason for the further western path.
Can you explain what draws you to that conclusion?

Well this system would continue on the path WNW with a slight stepping of NW and goes over almost all of Cuba, will cause it to weaken to possibly a Tropical Depression before coming back out into the Central GoM or even the South Eastern GoM (near the Keys) which would cause him to move further west while strengthening and if the models are correct the steering current is going to be so light come Monday Night thru Wednesday, that we might be seeing a major shift to the West in the next couple models.

[tropicwatch]

Right now it looks like Isaac might be taking a breather and becoming almost stationary, based on satellite imagery and recon.

[TropicalAnalystwx13]

Not sure why people are saying there's not an eye when it's very visible on geostationary imagery and microwave and recon reported a partial eyewall structure.

[JamesCaneTracker]

Not sure why people are saying there's not an eye when it's very visible on geostationary imagery and microwave and recon reported a partial eyewall structure.

The very next pass through they stopped reporting the eye meaning there is none again... All passes after that same thing. There was only a single pass that reported that eye.

[ozonepete]

Not sure why people are saying there's not an eye when it's very visible on geostationary imagery and microwave and recon reported a partial eyewall structure.

That's an "eye-like feature", a center of circulation, but it isn't a classic eye because this is not a hurricane and it is not embedded in a core of strong thunderstorms. As our understanding has increased as to what we traditionally called a hurricane eye and what we can see now on satellite and radar, we have to make distinctions between a true eye and an "eye-like feature". Notice how it's not really closed anyway - very open to the southeast and there is no core of thunderstorms around it.

[Hurricane Andrew]

And it [the eye] appears to not be the real COC.