Latest on the questionable strength of the ridge

[CYCLONE MIKE]

What do you all think of the trough digging down off the Texas coast. This looks like it could have an impact also if it ends up being stronger than models first thought. Looks like another reinforcing shot coming down south from Kansas/Oklahoma.

[dcuevas]

I have a question.... and I don't mean to sound stupid.... Is it possible Dennis can cause the High pressure over Central Florida to move back to the East and skate up the coast?

[TampaFl]

[Nimbus]

The ridge still seems to be holding but an interesting pattern is developing in the water vapor imagery.
The energy dropping down through Texas is no longer elongating the ridge from southwest to northeast across the gulf.
Instead it appears the energy will drop due south over Texas and leave a corner of the ridge up over NOLA?

[x-y-no]

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.

8 AM this morning:



Looks to me like the trend I mentioned yesterday has continued. That leads me to conclude that the current motion, which looks to be close to 330 to me, maybe 325, is a real shift in course, not a wobble. I think we see him crossing Cuba at about that 325 degrees, emerging on the north side at around 81.2 west plus or minus 20 miles or so, then proceeding in the direction of Key West and the Dry Tortugas.

Jan

EDIT: Sloppy navigation on my part - make that emergence centered on about 81.4W instead.

[Nimbus]

As of 8 AM we have WNW ridge flow over the Yucatan channel.
Look at the water vapor three hours later and you just start to see the ridge build northwest.
Too early to call but could be a factor later on.
Currently Dennis is bucking the ridge so we will see the wobbles for a while longer perhaps till he crosses over Cuba.

[dixiebreeze]

If you're right, Jan, it will be a very close call for the west coast of Florida.

[pavelbure224]

I noticed on the WV that the clouds over northern fl is going from SW to NE. Is that anything to worry about the future track?

[x-y-no]

If you're right, Jan, it will be a very close call for the west coast of Florida.

Not so bad, really. The lower Keys will get hammered if I'm right, but he'll still stay over 100nm offshore from the peninsula in my scenario (I'm to the right of NHC, but not overwhelmingly so). Significant weather, but not extreme. The panhandle is another matter.

Jan

[jpigott]

i don't know if anyone has mentioned this but from looking at the Key West long range radar loop and the visible/IR sat images it appears as if the northern eyewall of Dennis is very close to coming on shore in central cuba. When i look at the projected NHC path of the storm it has it coming on shore in Cuba a good ways west of where it looks as if it will make landfall.

[Scorpion]

Yes, definitely moving N and E of NHC track.

[PurdueWx80]

http://www.rap.ucar.edu/weather/satelli ... duration=4

This is a big, 4-hour loop of water vapor imagery over much of North America. The ridge is holding it's own out there in the central Gulf, and as a matter of fact, even seems to be building ever-so-slowly to the north and west. If this trend continues, the 12z NAM, which shows more bridging between the northern plains and southeastern ridge, may be on to something with it's further west track.

The shortwave over TX is amplifying but is not making any eastward progression whatsoever this morning. You can also see ridging trying to work north towards the trough in the Lakes states. The two are fighting right now, but a shortwave embedded within the ridge (wave in MT now) should be the kicker that will push the trough out of the Northeast. Also, now that the powerful upper lower over the Pacific is moving into BC and the Pacific Northwest, we will have better sampling of upper air flow. This will aid forecast models in predicting both the strength of that upper low and the downstream amplification (or not) of the ridge in the Plains.

What this all means to me is that Louisiana is not out of the woods here, and in fact, may be ground zero if the ridge continues to amplify as the 12Z NAM suggests. I also trust the UKMET more than most other models because of it's superior accuracy and performance on the synoptic scale.

[jkt21787]

http://www.rap.ucar.edu/weather/satellite/displaySat.php?region=CLT&itype=wv&size=large&endDate=20050708&endTime=-1&duration=4

This is a big, 4-hour loop of water vapor imagery over much of North America. The ridge is holding it's own out there in the central Gulf, and as a matter of fact, even seems to be building ever-so-slowly to the north and west. If this trend continues, the 12z NAM, which shows more bridging between the northern plains and southeastern ridge, may be on to something with it's further west track.

The shortwave over TX is amplifying but is not making any eastward progression whatsoever this morning. You can also see ridging trying to work north towards the trough in the Lakes states. The two are fighting right now, but a shortwave embedded within the ridge in the Northern Plains should be the kicker that will push the trough out of the Northeast. Also, now that the powerful upper lower over the Pacific is moving into BC and the Pacific Northwest, we will have better sampling of upper air flow. This will aid forecast models in predicting both the strength of that upper low and the downstream amplification (or not) of the ridge in the Plains.

What this all means to me is that Louisiana is not out of the woods here, and in fact, may be ground zero if the ridge continues to amplify as the 12Z NAM suggests. I also trust the UKMET more than most other models because of it's superior accuracy and performance on the synoptic scale.

Thanks for the thoughts Purdue. Couldn't agree more. Although NAM's depicition of the storm this morning if off, the track may not be. Still thinking its too west though, probably for of a MS/AL threat right now. The ridge is holding and may strengthen as you mention.

GFS should be out soon and will be interesting.

Louisiana, you are not out of the woods by a longshot.

[dwg71]

Purdue:
Thats a great look, but i see the ridge spinning off the coast of S Car, Dennis' outflow is supressed to the NE but its expanding nicely to the North. Cloud pattern over pennisula looks to be S to N.

Also, Go Buckeyes.

[MannyG]

Louisiana, you are not out of the woods by a longshot.

Local Mets are agreeing. After feeling real good last night that comfort is gone. One recently said the trough in the Western Gulf may follow Cindy and allow the high to build further west. Even though New Orleans is not in the target area I believe that the phase evacuation should start.

[x-y-no]

Yes, nothing I've been saying ought to be taken as claiming Louisiana is out of the woods. My strong inclination is that we're looking at a landfall a bit east of Pensacola, but if I lived in New Orleans I'd be preparing for having to evacuate.

Jan

[margaritabeach]

Purdue:
Thats a great look, but i see the ridge spinning off the coast of S Car, Dennis' outflow is supressed to the NE but its expanding nicely to the North. Cloud pattern over pennisula looks to be S to N.

Also, Go Buckeyes.

I think you meant go Hoosiers....don't bring up our football team though....

[soonertwister]

I just looked very closely at the IR animation of Dennis compared to the NHC track graphic side-by-side. I checked the motion of the animation at various speeds and came to the conclusion that for the 4 hours Dennis has been veering significantly to the right of the forecast track, possibly by as much as 30 degrees.

I'm sure its probably a wobble, but it's a pretty sustained one. If it continues much longer the NHC may have to make a very difficult decision. With Dennis now within 24 hours of potential landfall in Florida, if the rightward trend continues, then they will either have to issue a hurricane warning straight from a tropical storm warning, or they will have to stay such a decision, believing that Dennis cannot veer that much to the right.

I wouldn't want to be in their shoes right now. Dennis is an extremely dangerous hurricane that may come precipitously close to southwest Florida if the wobble doesn't turn back more toward the west in the next few hours.

[gtalum]

The second to last frame of visible satellite has Dennis' eye directly on the forecast point.

[x-y-no]

I just looked very closely at the IR animation of Dennis compared to the NHC track graphic side-by-side. I checked the motion of the animation at various speeds and came to the conclusion that for the 4 hours Dennis has been veering significantly to the right of the forecast track, possibly by as much as 30 degrees.

I'm sure its probably a wobble, but it's a pretty sustained one. If it continues much longer the NHC may have to make a very difficult decision. With Dennis now within 24 hours of potential landfall in Florida, if the rightward trend continues, then they will either have to issue a hurricane warning straight from a tropical storm warning, or they will have to stay such a decision, believing that Dennis cannot veer that much to the right.

I wouldn't want to be in their shoes right now. Dennis is an extremely dangerous hurricane that may come precipitously close to southwest Florida if the wobble doesn't turn back more toward the west in the next few hours.

He'd have to turn considerably more right to seriously threaten the peninsula. Right now, the extrapolation of his course over the past few hours would cross the Dry Tortugas - which I think is a credible scenario.

Jan