Tropical Storm Isaac, Part 2: Isaac Moving Into The Gulf Of Mexico-Hurricane Warnings For Morgan City, LA/MS/AL & FL Panhandle To Destin, FL

[SN_Lover]

That puts the center location well to the west of the official point.

im pretty sure this is the eye. looks ALOT more organized too

[wxsmwhrms]

That puts the center location well to the west of the official point.

That one ob looks bad so I don't think the wind analysis is necessarily right, but still I agree that it implies the surface center is a bit west of the advisory and likely disjoined from the mid level center (not surprising).

[wxsmwhrms]

Recon finding 50 mph southerly winds east of the center, should get a fix soon if it's over water, but that's not a sure thing.

Also checkout the new GFDL ensemble products, this will be a great tool http://data1.gfdl.no..._ISAAC09L∏=

Thanks for sharing that link - awesome! Right in the middle of that ensemble spread might not be a bad forecast right now.

[WeatherMimmi]

Im in Fort Walton and want to know since we all feel that we should have a better grasp on where this will land on sunday what time will the most important runs come out? Many here are waiting to see that info before boarding windows. Gas stations are running out of gas and water is already off the shelves. The tracks shifts east and then west and then east again remind me of Hurricane Elena in which moved all around.

[HurricaneJosh]

Im in Fort Walton and want to know since we all feel that we should have a better grasp on where this will land on sunday what time will the most important runs come out? Many here are waiting to see that info before boarding windows. Gas stations are running out of gas and water is already off the shelves. The tracks shifts east and then west and then east again remind me of Hurricane Elena in which moved all around.

The shifts haven't been that large, really. Most of the models have been consistently pointing to a landfall in this general region-- i.e., the Florida Panhandle. This having been said, I'm amazed places are already running out of gas, given this is currently a decoupled tropical storm over E Cuba.

[rcad1]

Are the remnants of Isaac going to stall over the se states or are they going to make it up into the ne???

[SBUWX23]

dry air and internal structure problems.

im pretty sure this is the eye. looks ALOT more organized too

[WeatherMimmi]

The shifts haven't been that large, really. Most of the models have been consistently pointing to a landfall in this general region-- i.e., the Florida Panhandle. This having been said, I'm amazed places are already running out of gas, given this is currently a decoupled tropical storm over E Cuba.

Gas trucks are in refilling but most people not only fill cars, they fill numerous gas containers for generators which many many people have here in this area after Opal and Ivan and then they fill up trailered boats with gas to make them heavy so they dont lift up with the wind and also serve as a reserve to hold extra gas for chainsaws ect.

The two major Airforce Base Eglin AFB and Hurlburt which house our Elite Special Forces have issued alerts and we are waiting for our instructions. In the mean time I dont think anybody answered the question of when will these runs happen on Sunday?

[SN_Lover]

dry air and internal structure problems.

i think it's a tad more better than it was before. you can see more cirrus clouds venting from the center. is that a bad thing?

[NavarreDon]

The shifts haven't been that large, really. Most of the models have been consistently pointing to a landfall in this general region-- i.e., the Florida Panhandle. This having been said, I'm amazed places are already running out of gas, given this is currently a decoupled tropical storm over E Cuba.

Alot of people in that area hear anything "Tropical" & immed. assoc. it with Opal, Ivan, Dennis & Katrina. I bet 1 in about 500 know what a decouupled TS is and that is either a fisherman or military personel.

[GaWx]

In the mean time I dont think anybody answered the question of when will these runs happen on Sunday?

By 2:30 PM EDT on sunday, the major 12Z models will have been released.

[Dsnowx53]

Thanks for sharing that link - awesome! Right in the middle of that ensemble spread might not be a bad forecast right now.

As you alluded to earlier, though, the middle ground track might not have much weight since it seems to make sense that either the trough is going to pull Issac NE towards Panama City, or that the trough won't do as much and more ridging will turn it NW towards the MS/AL border. Notice how only two of the members are actually in the middle, and very large clusters are to the right and left of the middle--making me think one of those two clusters is more likely to be right than a true middle ground track.

[WeatherMimmi]

Alot of people in that area hear anything "Tropical" & immed. assoc. it with Opal, Ivan, Dennis & Katrina. I bet 1 in about 500 know what a decouupled TS is and that is either a fisherman or military personel.

I did not know that term, but I do know one thing for certain that anything can change at anytime, we are talking about the weather

[HurricaneJosh]

Alot of people in that area hear anything "Tropical" & immed. assoc. it with Opal, Ivan, Dennis & Katrina. I bet 1 in about 500 know what a decouupled TS is and that is either a fisherman or military personel.

I'm using weather-nerd terminology for us. What I mean is, the thing looks like crap-- not even a decent tropical storm-- and it's 1,000 miles away. I think it poses a threat, for sure, but it's definitely not something to freak out over just yet.

[Superstorm93]

Center appears to be partially over land for now and could emerge within 6-8 hours.

Just received a dropsonde of 1001mb with 45 mph winds at the splash site.

The most important thing is that the circulation does not look "like crap" based on preliminary recon reports.

[Jaguars]

Very interested to see if 12Z Euro ends up being the trend setter that sets the final trend or is ultimately the outlier. 0z's should be fun

[turtlehurricane]

The circulation center is moving out of the higher terrain now, over 500-700 ft hills after hitting a 2400 ft mountain range, and the hills level off soon after this position. That'll give it a chance to heal, the southern semicircle could use it.

[jasons]

As you alluded to earlier, though, the middle ground track might not have much weight since it seems to make sense that either the trough is going to pull Issac NE towards Panama City, or that the trough won't do as much and more ridging will turn it NW towards the MS/AL border. Notice how only two of the members are actually in the middle, and very large clusters are to the right and left of the middle--making me think one of those two clusters is more likely to be right than a true middle ground track.

The fact that the models have been at times almost stalling Isaac would lend credence to this interpretation.

[U_Thant]

I would think you'd see a northward jog of the COC as the convective band on the E-SE side rotates around to the north side...ya know, angular momentum conservation and all...

[phil882]

One thing that has markedly changed with the guidance this morning is that the vertical wind shear expected over the gulf has been substantially reduced. Both the GFS and ECMWF now project a near perfect upper level pattern over Isaac in the 24-72 hour period with almost no restriction of outflow. While my forecast this morning of a hurricane before interaction with the Florida Keys might be on the high side, my second landfall intensity prospects look good and are probably on the low side given the expected upper level pattern. In fact, there is a possibility that 3 separate outflow channels may develop, which is normally only seen with the most intense tropical cyclones.

This possibility of RI is certainly increasing as long as Isaac is not too disrupted by its trek across Cuba.

[Quincy]

Convection is blowing up near or slightly NE of where the "center" is located. Will be interesting to see how the official center points track and develop into the night.

[andyhb]

Any thoughts on the OHC map posted earlier Phil? (the one that showed several cold anomalies though the Gulf)

[dan11295]

Center is right at the coast as far as I can tell. Now is the time we see if it moves into the strait or continues to hug the coast as has been eluded to earlier

[U_Thant]

I would think you'd see a northward jog of the COC as the convective band on the E-SE side rotates around to the north side...ya know, angular momentum conservation and all...

Well, my IR loop was little old (LOL) - it's already around to the NE quad, so perhaps a slight northward wobble is in order, but not all that much.

[PSUBlizzicane2007]

One thing that has markedly changed with the guidance this morning is that the vertical wind shear expected over the gulf has been substantially reduced. Both the GFS and ECMWF now project a near perfect upper level pattern over Isaac in the 24-72 hour period with almost no restriction of outflow. While my forecast this morning of a hurricane before interaction with the Florida Keys might be on the high side, my second landfall intensity prospects look good and are probably on the low side given the expected upper level pattern. In fact, there is a possibility that 3 separate outflow channels may develop, which is normally only seen with the most intense tropical cyclones.

This possibility of RI is certainly increasing as long as Isaac is not too disrupted by its trek across Cuba.

Great post Phil, and I have to agree that the RI potential is definitely worrying with the upper-level setup Isaac will have over the Gulf. I truly think all of this worrying about Isaac being too disrupted by Cuba is overblown.... obviously the major models disagree with it, and there is plenty of time for Isaac to recover.

[PSUBlizzicane2007]

Any thoughts on the OHC map posted earlier Phil? (the one that showed several cold anomalies though the Gulf)

Remember, as someone mentioned (I think Phil, but maybe Adam or someone else)... the TCHP has an issue where it will naturally show lower values closer towards the coast due to the shallowness of the water. Really, it will not be a major deal in inhibiting intensification of Isaac.

[Superstorm93]

Pressures are dropping as they make another pass through the elongated center.

Down to 998 with 28 knot winds.

[U_Thant]

Remember, as someone mentioned (I think Phil, but maybe Adam or someone else)... the TCHP has an issue where it will naturally show lower values closer towards the coast due to the shallowness of the water. Really, it will not be a major deal in inhibiting intensification of Isaac.

This. Charley encountered warm SSTs but decreasing OHC just prior to landfall. If any TC should have been sensitive to such a change it would have been a small TC like that. It wasn't.

[gulfcane]

Remember, as someone mentioned (I think Phil, but maybe Adam or someone else)... the TCHP has an issue where it will naturally show lower values closer towards the coast due to the shallowness of the water. Really, it will not be a major deal in inhibiting intensification of Isaac.

This was TCHP depicted 1 day prior to Felix strengthening to Cat 5 as it made landfall along 15 N. So to your point and plus people need to realize that insane tropical cyclone heat potential is not needed to become a major hurricane.

[phil882]

Any thoughts on the OHC map posted earlier Phil? (the one that showed several cold anomalies though the Gulf)

There is a cold OHC pool just to the west of where Isaac is expected to track, but this shouldn't be a main inhibiting factor since the storm will be moving between 10-15 mph. OHC becomes a much bigger deal when you have a large slowly moving TC which is what Isaac will do as it approaches landfall.

I know people have made the argument that near the shoreline the water is very shallow and therefore OHC products are not useful. However, I'd argue that you can still get upwelling in these regions, since instead of the water being replaced directly from underneath the TC, the water is transported from a deeper part of the Gulf of Mexico when it is overturned. Think of it this way, winds mix the water to a certain depth. If that depth is deeper than the depth of the water in that particular region, then it simply is drawn from another region. Remember that TCs are large entities, and the larger a TC the more upwelling you receive. Isaac is already a fairly large tropical cyclone, so it needs a surface heat flux from a large portion of the Gulf of Mexico to sustain itself. Thus, while the water directly underneath the system may not be cooled all that much directly below the central core, it almost certainly will be in other regions. Mixing is not just in the vertical, but also the horizontal, so the regions with cooler water will mix with the regions of warmer water, still cooling the warm SSTs near the shoreline.

Thus, upwelling may occur as Isaac slows down for its final landfall.

Great post Phil, and I have to agree that the RI potential is definitely worrying with the upper-level setup Isaac will have over the Gulf. I truly think all of this worrying about Isaac being too disrupted by Cuba is overblown.... obviously the major models disagree with it, and there is plenty of time for Isaac to recover.

Until the storm clears Cuba, I remain cautious, but I generally agree.