Scott's Aug, 2008 Blog
(blog descends chronologically)
 

UPDATE 7:30PM: Gustav's day has been both a forecasting fascination and frustration. Thankfully, a day of Cat-5 intensities hasn't been experienced and the hurricane has indeed struggled mightily to stay above Cat-2. Tonight, on final approach to the south shore of Louisiana, Gustav is tightening up and looks to organize and possibly strengthen.

Current view below (click for more).



Thunderstorms and deep convection appears to have now completely wrapped around the center. As this is written, the eye is obscured but is near the top of the deep (red) and it is possible the eye will soon reappear and that is a foreboding signal. The other bothersome item is from the Hurricane Hunters, who report the temp difference between the outside and the inside of the eyewall is 10°C. This temperature gradient usually accompanies strong hurricanes. (tropical cyclones are warm core storms so the warmer temps are inside the eyewall).

 

Ghost Town: Looking down Jeff Davis Pkwy into downtown NOLA and the CDB this afternoon at 3:42 CDT. The Superdome is easily spotted in the background.

Hanna: I again urge people in Florida and the Southeast/Mid-Atlantic to now closely monitor NHC forecast tracks for Tropical Storm Hanna. She's still a mess but by mid-week will probably  organize and head toward the US coast...somewhere between Jacksonville, FL and Myrtle Beach, SC. We're running model maps at our Premium Service site. Current track brings Hanna inland near Savannah on Friday. NHC's cone of probability currently extends from Miami to Wilmington, so we have a long way to go!

Brief touch-up on Gustav tonight around 11PM EDT.

UPDATE 10:35PM:

Gustav: Trying to intensify but becoming elongated...as such, rapid intensification is unlikely. Very doubtful this reaches Cat-4. Bands coming inland and SPC has issued a Tornado Watch from E LA to the FL Panhandle. Severe weather and tornadoes can and do occur well away from landfall...persons in the affected area must exercise caution overnight and Monday. All computer modeling I've seen from the 0Z runs keep the center west of NOLA. As noted earlier today (above) the CGUN consensus has done very well and this will also be watched closely with Hanna.

Hanna: Convection firing up tonight in a more organized fashion:



Huge diversity in models with UKMET down in the Florida Keys and the HWFI north of Wilmington...passing between Richmond and Williamsburg, VA. Only trend with models is a likely landfalling strong tropical storm or a hurricane. We need to get past Gustav but want folks in this area to closely monitor this storm as it could come inland as soon as next Friday.

Next update in the morning. Thanks to the many folks who used the AOL Instant Message box tonight to say hello and share information. Have a good night and stay safe.
 

Gustav: This morning has featured two interesting items. First, the storm has undergone strengthening as forecast with more deep convection blooming just to the NW of the eye. Current image below (click graphic for more):



Second, the 8AM EDT "intermediate" Advisory from the NHC positioned the center to the north of this morning's 5AM forecast track:



Looking at current Radar from Punta del Este, Cuba the track appears generally to the Northwest. It is important to remember that tropical cyclones rarely traverse water in a straight line...there are frequent shifts and "jogs", so we don't know if or how this affects the ultimate landfall zone. It is possible the NHC shifts Gustav's track to the east (closer to NOLA). It is equally important we focus on the cone of probability as this storm has a long way to go.

Cuban Radar leads us to believe Gustav will pass over Isle of Youth before rolling into Cuba this evening. Western Cuba does have some hilly terrain but it is not mountainous and the storm should only diminish by 15 MPH. Visit out Interactive Map HERE and pan/zoom in on Cuba, then click Ter (terrain view) in the upper right corner to see more.

There is a chance Gustav is a Cat-4 at time landfall on Cuba although a direct hit on Isle of Youth may keep the storm a Cat-3 for Cuba.

We often talk about storm's "bombing out" and Gustav has done so in the past 24 hours. The loose definition of a storm bombing out is a drop of at least 24 millibars in 24 hours: Gustav was 988mb at 12Z on Friday and 955 this morning at 12Z  (impressive 33 mb drop). Satellite estimate now puts minimum central pressure at 933 mb: if the estimation verifies that is a huge drop in 24 hours and denotes a rapidly intensifying and organizing hurricane. Again, Isle of Youth and western Cuba will have some impact but the storm should eject Cuba on Sunday morning as a Cat-3. Next comes the very warm loop current in the Southern GOM and Gustav will quickly ramp up to a Cat-4. The NHC gives Gustav a 4% chance of producing Cat-5 winds...my opinion is that is low and a healthy storm exiting Cuba has a 25% chance of reaching Cat-5. Either way, we have a dangerous hurricane.

The next issue is surge. Gustav will grow to be an expansive storm in the GOM. A wide wind field (fetch) is what pushes surge toward land. Here's the graphic for hurricane force wind probabilities. This is the worry for the North-Central Gulf Coast. Two to three days of hurricane winds will force a tremendous amound of water up into the northern Gulf with the greatest risk appearing now to be the Bijous of Louisiana and Mississippi. Even if Gustav jogs slightly west or east there will be a strong push of water and this time, it appears folks are taking this threat very seriously.



Gustav may remain a major hurricane all the way to landfall...but that isn't a given. Early next week, shear from an Upper Level trof is expected to increase and the tendency of storms on this track is to weaken on approach to land (cooler water temps, more shallow water and interaction with land). But, there's not much difference between 110 MPH and 115 MPH so preparations and evacuations are well underway. Tomorrow, we'll discuss model trends and landfall intensity probabilities in more detail.

We're constantly updating our HurricaneCenter and if you're interested in our hurricane model maps, please click here.

I like WWL TV in NOLA and find their coverage to be reliable without alot of hype. You can watch here.
WWL Radio requires free registration before listening to their excellent live coverage. Click HERE.


HANNA: Hanna still is being sheared and convection isn't rotating around the LLC; this is owing to the Upper Level Low (ULL) we've discussed here for days. This feature should relax and allow Hanna to get pulled together...but that is not a guarantee

This is an odd storm that still is forecast to track Southwest (Betsy did this in 1965...ultimately landfalling in both SFL and Louisiana!). It just is not common to see a tropical cyclone climb in latitude and then go south...but obviously it can occur. Current track brings Hanna up to a hurricane and then weakens through the Bahamas as she dives toward central Cuba next week. Models are extremely jumpy and thus far have not "figured out" sensible weather and steering currents. Some models are ebbing more toward SFL and this morning's GFS surprised me by taking Hanna into Jacksonville and then into WV! Obviously, the outlier but very curious.

We have the benefit of time to watch how this unfolds. Right now, there's much uncertainty as to forecast track. There is the possibility Hanna gets into the GOM next week.


INVEST 97L: Currently just SW of the Cape Verde Islands, the hurricane models are bringing the storm north of 20° near and east of 60°. This benchmark is frequently used to anticipate the possibility of a storm approaching the Caribbean or US. This is a long way off and with a full plate now this discussion will be brief. There is some model support for "97L" to approach Florida so we need to watch. Right now the focus is on Gustav and Hanna.


RANT: We don't do politics here, but my (infamous) Irish temper has been put to the test. Keith Olbermann had filmmaker and verbose nut job Michael Moore on last evening's Countdown to mark Katrina's third anniversary. Moore, commenting on Gustav's potential landfall said: "There is a God". Olbermann continued the conversation, never rebuking this comment about hoping a major hurricane hits the US Gulf Coast. Apparently, they dislike Republicans so much that a catastrophic hurricane hitting NOLA during the convention is a good thing. Hoping a major cane hits NOLA and then say "I hope no one gets hurt" could be the most disingenuous and hateful comment I've ever heard on a supposedly credible network. Video on Youtube. You may need to shower after being slimed.


I'll update the blog around 11PM tonight.

UPDATE 10:35PM: Unwelcome changes today with Gustav and Hanna. Game face on on so let's get right into tonight's update:

Gustav: Eye of the storm now exiting north coast of Cuba. Using Water Vapor for tonight's current image
(click for more):


If you've been watching satellite loops tonight you'll notice the eye is ragged and deepest convection isn't totally wrapped. As a result, it is most unlikely Gustav will be a Cat-5 until Sunday morning. In fact, the NHC forecast is predicting part of the track to be Cat-5...this is VERY rare!



The NHC Forecast/Advisories at 11PM, 2AM and 5AM may enumerate a weaker storms and we absolutely do not want people thinking Gustav is falling apart. He is not. As can be seen, Gustav is expected to be a Cat-5 with winds exceeding 156MPH on Sunday morning.

Evacuations are extremely well broadcast on local NOLA media (except the Fox station advising people to wait until morning...don't do that). Gustav will undergo at least one ERC (eyewall replacement cycle); this causes wobbles and jogs in the forward motion and also fluctuations in intensity. I frequently advise people that major hurricanes do not like being micro-managed...follow trends...not every frame of a satellite loop. These jogs can and will bump the forecast track slightly but there is overall excellent agreement with modeling that Gustav comes into Louisiana probably in Vermillion (the MOST Cajun place on Earth) and Terrebonne Parrish.

Talking with reliable NOLA folks I'm hearing growing concern the levees may overtop from Morgan City over to the West Bank (this does not include the downtown area levees). Storm surge of 15-20 feet remain likely just east of the eye. Outer bands are now less than 36 hours away.

HANNA: Forecast track for Hanna continues shifting to the west and WNW...a total change in thinking from this morning! Time precludes a thorough discussion of the cyclone and it is several days away. My concern is Gustav is a major story but folks in Florida, along the Gulf and Southeast coasts absolutely need to monitor this event as well. Right now, the models are "a plate of spaghetti" but coming around to a solution that takes the tropical storm into the Bahamas and then toward Florida and the Southeast coast. Pease do not disregard Hanna due to Gustav! Hanna has the potential to become a Cat-1 hurricane.

Next update on Sunday morning.
 

UPDATE 10:35PM: Not seeing any "extremo" returns on the radar loop below although the center of circulations is discernable:



I'll admit my forecasting on Gustav has been paltry, at best. Last evening, I indicated the storm would regain hurricane strength as soon as it was over water but that didn't happen...in fact Gustav remains a weak mess. And while I believe the storm may ultimately landfall  west of NOLA...the NHC does not agree. So, here goes my fearless forecast for tonight: Gustav has one more day of this before we get to The Big Show.

Looks to me like the "center" is jogging or moving to the WSW or Southwest so we'll see if Gustav pulls a Fay and hits virtually every possible speck of land in the Caribbean! The storm is still being steered by high pressure to the north and this should continue through Thursday. On Friday a trof over the Eastern US is expected to slightly dent (produce a weakness) in the Ridge and Gustav then can be steered more to the Northwest and eventually into the GOM. That remains the thinking tonight.

As this is written the 11PM EDT package has been released. NHC has shifted west but just a tick and also lowered maximum strength down to 95KTS. This makes sense given Gustav's center is no longer beneath the strongest convection. Far from dead...the tropical cyclone will need to clear Jamaica before getting pulled together once again. Sounds like a much weaker storm? Far from dead! We'll close with this comment from tonight's NHC Discussion:

IT PROBABLY WOULDN'T HURT TO REMIND EVERYONE THAT THE AVERAGE 5-DAY OFFICIAL 
TRACK ERROR IS ABOUT 300 MILES...AND THE AVERAGE 5-DAY INTENSITY ERROR 
IS ABOUT 25 MPH.

GUSTAV IS MOVING TOWARD THE WEST-NORTHWEST NEAR 8 MPH...13 KM/HR. A TURN TOWARD THE WEST 
IS EXPECTED ON WEDNESDAY...WITH A RETURN TO GENERAL WEST-NORTHWESTWARD MOTION FORECAST 
TO OCCUR ON THURSDAY. ON THE FORECAST TRACK...GUSTAV SHOULD PASS BETWEEN JAMAICA AND THE
SOUTHEASTERN COAST OF CUBA ON WEDNESDAY AND THURSDAY.

(BTW, I'm delighted to see Stacy Stewart's name back on an NHC package. He [yes, he] is among the best of the elite at 
tropical cyclone forecasting. He also happens to be one of the nicest guys around).

Hispaniola has again taken a chunk out of a hurricane and Gustav is down to tropical storm status at 11PM. The cyclone is
now moving over water and will soon regain Cat-1 status.

We can't answer the big question right now: where's Gustav going. But, we are seeing some trends among various models.  
The fairly reliable UKMET, "Euro" and the GFDL all charge a major hurricane toward coastal south-central Texas. This bothers 
me because these models have been good but for unclear reasons to me shoot right through an upper trof (TUTT) between the 
cyclone and the Texas coast. That does not seem at all reasonable. Meanwhile, the NOGAPS appears far too East to verify...
it almost looks like there's no TUTT or Ridge! With Ridging to the north, steering winds should keep Gustav on a westerly 
track over the next two days (depicted in NHC's forecast track). The storm will again be a hurricane and will "feel" a weakness 
in the Ridge and more of a NW track is then forecast. This brings us to the possibility Gustav misses Cuba and gets into the GOM 
on Saturday.

We are several days away for pinning down a reliable cone of probability, but for tonight, my first guess would be 
Matagorda Bay, TX to New Iberia, LA. This is NOT an official forecast and certainly will shift as the storm heads toward the Gulf.
A very unscientific recommendation would be to warn all interests from the Yucatan to Big Bend.

Models remain too jumpy for any reasonable degree of confidence beyond 48 hours. Stay close to our HurricaneCenter and if 
interested in our hurricane model maps, please visit here.

INVEST 95L: Gotta give a quick shout-out to Invest 95L, now NE of the Leeward Islands. This Invest comes and goes faster than 
change at a slot-machine...but that may be changing. Several models keep the storm going and eventually becomes a Tropical 
Depression. Unfavorable conditions mean this is worth a watch but no threat to the US in the near future.

More Fay: Flood watches and several warnings have migrated north into Eastern TN, Western NC and extreme SW Virginia as Fay 
continues to ebb toward into tropical oblivion. Check our Severe StormCenter for the latest. 

UPDATE 10:40PM: A couple thoughts while awaiting NHC's 11PM EDT Forecast/Advisory. Models are beginning to trend AWAY from Florida and more toward the "hurricane" BAM models and the (OMG!) the Canadian. This is due to more quantitative and qualitative data from the hurricane hunters earlier today. It also appears we're starting to get an early handle on sensible weather over the next week for the Caribbean and US. Upper level High Pressure over Florida should help guide Gustav away from the peninsula for at least a couple of days. The track of the storm would therefore head Northwest and then more to the west. If this develops over Cuba the storm should lose some punch but still menace both the island and the region. A trof of low pressure advances toward the Gulf this weekend and this should begin to help Gustav return to a Northwest track. Where will this happen? I don't know. But I think the strait up to Florida track will not verify. Maybe the Yucatan Peninsula actually is now in play. Second thought: the trend early on with Caribbean and GOM storms is to the west that should be the case with Gustav.

We should have a hurricane by this time Tuesday night on a track approaching the western tip (again) of Hispaniola and then Jamaica. Keep an eye on things at our HurricaneCenter. If you're interested in our hurricane model maps, please click here.

Have a good night.
 

UPDATE 9:50PM: Fay crossed Key West at 3PM this afternoon and the center remains over water at this time. Center has nicely organized late afternoon and tonight...just in time to try reaching Cat-1 status at landfall. Current enhanced view:



Fay may come in close to Punta Gorda...but certainly not the monster that Charley was when he crashed in the same area. From here, Fay will spin up toward Jacksonville and then things get a bit sketchy! The GFS and UKMET "about face" the storm and shoot west...passing Tampa and getting into the Eastern GOM. In fact, the 0Z GFS and the BAMS takes the storm towards NOLA! Most models are not this sharp but there's good agreement the extremely expansive Ridge over the Atlantic will steer Fay to the west. I'm sure folks up here in the Mid-Atlantic States have noticed Fay now is not expected to bring needed and beneficial rains to the region. I am not sold on any solution that takes Fay's remnants along the Gulf Coast or near NOLA...but it is interesting and will be closely watched.

INVEST 94L: Hmmm...tonight's GFDL puts Invest 94L smack dab where Fay is now located!  That may be premature but it is more that a little interesting because the aforementioned Ridge will rule the Atlantic into next weekend. This should shut the door on any tropical systems making headway up the coast. However, South Carolina, Georgia, Florida and the Gulf would appear open for business. Conditions are somewhat favorable for development and "94L" could become a Tropical Depression in the next two days.
 

Current approximate position of surface low pressure here:

Current steering winds are not supportive of a large northerly component in Fay's track over the next 24 hours.

Low Level winds (700-850mb or up to roughly 4,500')

UPDATE 10:45PM: No changes tonight to the ideas of earlier this morning. Convection still struggles for form and hold over the center...the storm continues tracking a tad north of due west and will hit Cuba near Pilon then reemerge over the Caribbean while beginning to turn more to the WNW...hitting Cuba a second time on the west-central end of the island. Thinking behind forecast track essentially unchanged as well: presuming Fay actually does begin turning more to the north, SFL up the Gulf Coast to Tampa remains the logical target zone on Wednesday. I'm concerned intensity forecasts from the models remains low confidence. The GFS/ANV still will not intensify Fay while tonight's HWFI puts a strong Cat-2 SW of Tampa. While computer guidance is now mostly western Peninsula with some tracking into Big Bend, intensity is  far from agreement. Convection is really cranking tonight making for more extensive cold cloud tops...this impacts future storm strength as well. Hopefully recon flying in tonight helps with tomorrow's 12Z models.

If the chronic westward movement continues overnight we may see the panhandle and Big Bend come more into play...with an increase in storm intensity.

Florida Folks: expect the first issuance of watches Sunday morning.

Tourism evacuation begins Sunday on the Keys.

Radar from Cuba show eye rotation

Key West, FL Radar
 

). Hurricane Hunters out this afternoon found no LLC (low level circulation) and so it remains a tropical wave. Current approximate position of surface low pressure here:

Current enhanced satellite view (click image for more):



Tonight, the low is over the US and British Virgin Islands and moving just north of due west (280°) at a relatively quick 15MPH. Using this Google map, we get a close up view of where Invest 92L is located. If the "fix" for low pressure is correctly located and the storm continues roughly on a 280° course (W-WNW), it certainly looks to me as though it will pass over San Juan and the north side of Puerto Rico. In fact, rain from "92" clearly shows up on Radar from San Juan, PR but I see no evidence of banding or circulation in the long range radar. So, we continue to watch.

It appears the storm is not "stacked" and while there is circulation in the mid levels (evidenced by the spiraling seen above), Low Pressure at the surface is displaced away from the mid level where the rotation is located. This is the reason we don't yet have a TD or "Fay". Radar backs up this thinking because if the Low at the surface was closed off the rain east of San Juan, PR would show some counter clockwise circulation...and we'd have a hint of banding features. As of now, it's just not there.

We'll assume "92L" passes Puerto Rico and then we'll need to see how much interaction the storm has with Hispaniola. Landfall or near miss, the storm gets disrupted by the big island and it's merely a matter of how well organized the center is before it gets there. A well defined storm would suffer more damage than would a TD or weak tropical storm. And keep in mind, the highest mountains are located on the southern half of the island. At this time, no model guidance has the storm rapidly intensifying by the time it approaches Hispaniola on Friday night.

Beyond Hispaniola, there is great uncertainty. A trof of low pressure comes down over the Lakes, Northeast and Mid-Atlantic this weekend (thus a continuation of cool and cloudy weather). This trof won't reach the Deep South or Gulf and is expected to lift out over New England towards the end of the weekend. High Pressure builds over the west and central Atlantic Ocean and "Fay" passes Hispaniola and in all probability, Cuba.

You get a sense of how this looks by examining the low level steering currents. I'm using 700-850mb because "92L" is still a weak storm:



You can see the Upper Level Low as a counter clockwise swirl over Canada; that will bring the trof over the Eastern US. High Pressure is the expansive oval over the Atlantic. Note the streamlines helping to steer "92L" towards Hispaniola and Cuba. This will be important to watch because that High Pressure ridge will move west toward the United States and where it sets up will help determine where the storm will go.

Should the ridge build well to west it would steer the storm over Cuba (the Euro's suggested track). If not, the storm would probably be steered more toward SFL or even up the east coast of Florida and toward the Carolinas.

My hunch right now (NOT a forecast) is for the storm to clip east/central Cuba and then track NW toward the Keys or SFL. Tonight, I can not rule out the possibility of the storm missing FL and coming in somewhere along the Carolinas. But again, until tonight's "blob" clears PR and Hispaniola and there is an actual LLC, this is all speculation.

As far as timing goes, if the storm does not slow down or stall due to weak steering currents, we may be looking at a strong tropical storm or perhaps a hurricane anywhere from the Florida Straits to central Bahamas on Tuesday. As such, all persons in the Caribbean, Florida and Southeast US should now closely monitor the storm's future developments and be prepared for action.

Is there a chance this fails to organize before crossing Hispaniola and Cuba? Yes. If that happens, any renewed development would likely occur over the Eastern Gulf of Mexico. So, it is possible we could be fooled by Invest 92L and there's little development. More likely, we have a potentially serious tropical cyclone to contend with in less than three days.

Keep an eye on things at our HurricaneCenter. If you're interested in hurricane models please learn more at Premium Service Hurricane model maps information page. I have a feeling Florida Folks will be giving our model maps pages a workout this weekend!

Next update Friday night...earlier as developments warrant. Have a good night.
 

Reminds me of Floyd '99; in fact, many models mimic Floyd's path of coming up and getting close to Florida but not making an actual landfall. Until there is an actual LLC and some reliable recon, there really is no way to pin this down tonight. However, some observations can be made. The Water Vapor Loop shows there's still ample dry air ahead of the storm and this will continue to inhibit rapid growth. Wind shear will increase ahead of the storm, especially if it tracks up into the Bahamas, so there are factors against "92L". And, if the cyclone does skirt the northern coast of Hispaniola (as suggested above by the GFDI), it will take a beating for over 36 hours. There's a reason why the island is nicknamed: "The Blade". While I think computer guidance makes sense out to 72 hours, I'm not sold on an East Bound and Down, Load It Up and Truck It scenario where the storm comes at Florida and then zips up the East Coast.

Intensity wise, I'm concerned the AVN/GFS still isn't on the storm as of yet and continues to keep "92L" a weak, undeveloped wave. The HWRF/HWRI keep it a minimal tropical storm while the GFDL/GFDI  put a Cat-3 hurricane in the Bahamas. The Euro (ECMWF) follows the GFDL but shifts to the southwest over Cuba in response to short term Ridging, then landfalls as an apparent hurricane at SFL before tracking up the East Coast.

There are many questions and few answers tonight and we'll see if the hurricane hunters sniff out anything overnight or on Thursday. At this time, Puerto Rico, Hispaniola and Cuba should monitor possible developments. The Bahamas, Florida and SE coast really need to keep an eye on this. Were I along the North-Central Gulf Coast, I'd be watching as well: if the downstream trof/Ridge setup doesn't pan out as the models depict, any storm will end up in the Eastern GOM by Monday night.

Next update will be Thursday afternoon. Have a good night.
 

In terms of intensity, that is tough to pin down because the models don't have a storm, nor is there steady input of surface data. The AVN/GFS poohpooh the storm altogether while the GFDL/GFDI bring it up to nearly a Cat-3
in the Bahamas! Meanwhile, the ECMWF appears to have a major hurricane just south of Louisiana in the Gulf next Wednesday! So, we have a wide range of possibilities and really can't pin it down until there's an actual low level center.

Certainly, the Southeast Coast, Florida and GOM should monitor developments however this isn't going to explode overnight.

INVEST 93L is east of "92L" and I'm doubtful anything gets going. The dry air that has plagued Invest 92L will do likewise with "93L" and it will soon move into a very strong shear environment. As such, I think it's a goner and Invest 92L will be the show this weekend.

Next update here at the blog will be Wednesday night.