Forecasting the Forecasts
Ike to Strike
Posted by: mcmurray02, 08:23 AM GMT del 11 Settembre 2008 +0
Here's what I'll be discussing on Ike:

1. It's intensity forecast, now and at landfall.
2. Projected Path
3. Impact's on Texas

First, the intensity. It seems that as of this writing the NHC is torn between whether Ike will intensify greatly, or whether it will weaken.
Here's what they are saying:

HURRICANE IKE DISCUSSION NUMBER 40
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008
1100 PM EDT WED SEP 10 2008

...

THE SHORT-TERM INTENSITY FORECAST IS CONTINGENT UPON HOW LONG THE EXTREMELY SMALL INNER CORE SURVIVES. SINCE IT COULD DISINTEGRATE AT ANY TIME...AND SINCE IKE WILL BE PASSING NEAR OR OVER A COLD EDDY IN THE CENTRAL GULF DURING THE NEXT 24 HOURS...THE HURRICANE COULD WEAKEN. IF...HOWEVER...THE TENACIOUS INNER CORE REMAINS INTACT...AND GIVEN THE RECENT PRESSURE FALLS...IKE COULD STRENGTHEN SOME AS REFLECTED IN THE OFFICIAL FORECAST.

'''



First, I don't think that the inner eye will disintegrate because there's been a very good spiral pattern all the way down to the eye wall. Also, if I'm not mistaken, I've read that the inner eye wall collapses only if the 2nd eye wall cuts off its circulation by preventing air intake. That only seems to happen in a very mature stage of development. Though this is a very mature storm, with a huge wind field, its inner core structure has remained very youthful looking. This could be attributed to the fact that the outer bands have a lot of momentum going on and are spinning away fast enough that the storm's core will have some time before it catches up. Its sort of like pedaling an exercise bike very quickly and then letting off, the wheel keeps turning, but you've got hit a pretty good pace before you gain traction with the wheel again. This is essentially what happened to Ike when it hit Cuba, except in this case its a much bigger, series of wheels loosely connected by belts.
Here's a pic of its tiny eye:



Small but persistent eye's tend to lead to rapid storm development, but the outer bands are too developed and have been mixing with some nearby dry air. This dry air is why I think Ike isn't over intensifying, which would lead to an inner eye collapse. That dry air hour glass is about to run out though, take a look at the water vapor:

Notice on this map, which I stitched together on Google Earth, I have circled dry pockets of air in Ike's sphere of influence. All of those are shrinking. The main concern for Ike's development is the one to its SW, because that is cutting moisture off from its moisture primary intake valve. That pocket doesn't have much time left. You'll take notice that this setup is the opposite of Gustav, Katrina and Lili that I wrote about in my previous blog entry about dry air entrenchment. As soon as the storm pulls enough moisture from the north it will fill in that moisture void it will eventually give that intake valve some more fuel. When that happens, I expect rapid development to a mature storm to occur. That moisture supply should be good as its being fed by Tropical Depression Lowell, which is a Pacific system moving towards Texas from the west and an upper level low coming in off the west coast (both circled in green.)

Now, that leads me to my next point, once this hurricane ramps up to its peak force, its not going to have an excuse of dry air entrenchment like so many of its predecessors in the GOMEX. The only thing that will slow it down will be EWRCs (eye wall replacement cycles.) The cool eddy's are there, but given the storm's large size and momentum, it'll be hard to stop this train once it gets going.
Here's a look at the total heat content in Ike's path:


The closer these warm areas are to the core, the more likely the storm will be able to strengthen. Keep in mind, what you see here is not the actual temp, but a measure of the deeper heat content. Having said that, the surface temps are all running into the upper 80's in all points along the way. I expect the hurricane to make it to at least a Cat. 4 and maintain a high wind speed level up until landfall. Even when landfall occurs, the top wind speeds may drop, but the area of hurricane force winds are expected not to reduce very quickly due to the enormous size and great momentum the air around it already has.

Now, the landfall forecast. I think the NHC finally has a track down that I can mostly agree upon. I've been leaning towards it hitting west of Houston, but moving east of Dallas since last weekend. I specifically think it'll hit Brazoria County, move up to just east of the College Station area, and up through Kaufman County on its way out as part of the font to the eastern Great Lakes region.
Here's my projected track (in blue, NHC in red):

It's just not going to be a good day to be on Surfside beach when it hits. Now, one other very important thing to understand is the size of it's wind field. I've also placed two zones (red and orange) to represent hurricane and tropical storm winds, respectfully, at the time of its landfall. Now, that's based on its current wind field, which could grow some more before Saturday when it's projected to hit. (Keep in mind this is only when the eye reaches land, this will contract but keep moving as it progresses further inland.)

For the rest of Texas, I think Austin may get the short end of the stick on the rainfall, but any place within 120 miles of its landfall all the way northward to the DFW area and eastward into the Piney Woods should get plenty of rain. The inland winds should also be far reaching. It would not surprise me to hear about TS force winds with occasional gusts near hurricane strength as far north as Waco or Corsicana. I expect sustained hurricane winds through the entire Houston/Galveston area and reaching as far inland as College Station and Hunstville. Could the projected path change? Absolutely. But, don't expect it to pull a Rita and deviate as far this time. Mainly this is due to the fact that the storm is going to be moving in more perpendicular than parallel to the coast relative to Rita.

The impact of this storm is potentially very huge. Thankfully, its not likely to be as deadly as Katrina, but a landfall in the wrong place could be just as expensive as Katrina, especially if the storm lands where it's currently projected to land. If it where up to me, I'd urge everyone in its path along the coast to start leaving now with plenty of time to spare. There won't be time to second guess this.

The bottom line is that this storm will be a historical storm, it will cause wide areas of destruction, it will temporarily shut down some refineries and imports, and over all its just not a pretty thing. I hope I'm wrong, but my early intuition is that this is the Storm of '08.
Updated: 05:56 PM GMT del 11 Settembre 2008   Permalink | A A A
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Post Gustav Discussion and a super busy Atlantic
Posted by: mcmurray02, 07:44 AM GMT del 03 Settembre 2008 +0
{Original post from 9/3/08}First, now that I'm back for my first update since Fay, let's talk about Gustav. Gustav was the big storm that didn't. That's not to downplay those have have suffered on the coast, its just to say that we we're right on the fine line between, just another 'cane and major disaster. So, why didn't Gustav not become the super disaster that just seemed inevitable on Sunday morning? The quick answer to that is dry air entrenchment. Sure, there ...
Updated: 05:11 AM GMT del 11 Settembre 2008   Permalink | A A A
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What's next for Fay?
Posted by: mcmurray02, 02:29 AM GMT del 21 Agosto 2008 +0
Well after an interesting turn of events (track model shifting and intensity surprises,) its time to take a look at where I think Fay will go to next. I think Fay will head west, go up to Alabama, maybe Mississippi do a loop-de-loop as it hooks up with the low that’s currently giving us rain here in North Texas. While there, I think it'll dump lots of flooding rains and then it'll head on east, finally heading up the eastern seaboard, and off to the polar belts. I...
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Fay Saturday Morning
Posted by: mcmurray02, 09:21 PM GMT del 16 Agosto 2008 +0
Well, this morning there are some interesting looking satellite images of Fay. A lot of folks are confused about why the NHC has placed the center of circulation north of what most people consider the center. Take a look at this and see what you think:I captured this frame right as the sun began to rise to allow the shadows of the storm clouds to be visible. As you'll see, there is a large plume of a very symmetrical circular south of the center that appears to have...
Updated: 06:36 AM GMT del 17 Agosto 2008   Permalink | A A A
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What a differece a Fay makes - post for Friday evening.
Posted by: mcmurray02, 08:40 PM GMT del 16 Agosto 2008 +0
Well, a day after giving an analysis on Thursday over what has now become Fay, it looks like all of the models have shifted to the west. When Fay was upgraded to a named storm, it skipped straight into a tropical storm. This doesn't surprise me, as this is not too uncommon. What was interesting is that at the time that it was named, it was officially over land in the southern area of the Dominican Republic. Also, while over land at its second advisory, it's wind fie...
Updated: 09:48 PM GMT del 16 Agosto 2008   Permalink | A A A
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This is going to focus (1) North Texas weather (2) Tropical Weather and (3) forecasting the forecasts.

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