Harvey: The Sequels

By Chuck | Published Friday 25-Aug, 2017

Harvey is the storm that just would not quit. It formed in the Atlantic and died in the Caribbean. It reformed in the Bay of Campeche and now threatens the middle Texas coast as a Cat 2, potentially Cat 3 Major Hurricane. If you live on the Texas coast, between Corpus Christi and Freeport, you need to be listening to local action statements and rapidly preparing for the impact of a potentially major hurricane. That means winds to 120 mph, a surge of anywhere from 12-15 feet, and rainfall amounts approaching three feet. This is no longer a potentially deadly situation but a probably deadly situation. Get out while you can!

So what about the rest of us? Well let’s recap what we know right now: Harvey at 9 am was located at 26.5 N 95.9W or about 135 SSE of Port O’Connor Texas. Max winds are 110 mph and climbing, it is moving NW at 10 mph and has a central pressure of 948 mb. This remains a quickly intensifying storm and it should be Cat 3 as it approaches the Texas coast. One way or another, our friends from Corpus to  Freeport are going to feel the brunt of a Cat 3 hurricane over the next 24 hours. And if this were a normal storm, it would push well inland and fall aprt with the remnants swept up to the NE eventually by the jet stream. Not Harvey!

The image to the right is what the hurricane center is thinking will happen. Quite frankly it is the best case scenario for the upper Texas and Louisiana coasts. It depicts a storm which comes ashore as a Major Hurricane early Saturday and by Sunday is about 60 miles inland as a hurricane and stalled. By early Monday it is back near where it made landfall, late Tuesday near Freeport as a Tropical Storm right on the coast, and Wednesday over Galveston as a Tropical Storm. Harvey, the storm that would not quit.

If this plays out as the actual path of the system, those of us on the Upper Texas and Louisiana coasts will get lots of rain, more on that in a bit, and some windy tropical storm like winds and conditions. All in all, not a bad outcome from a Cat 3 storm. But the problem is, as the NHC always tells us, don’t look at the path line itself, but rather the general motion. This is because the actual path is likely to deviate by as much as 60 miles, even in the short term. Therein lies the rub. The Hurricane Center has been shifting its products a bit to the east consistently over the past few days as the major models fight about the future course of the storm. The European model, arguably the best in the world has one idea and the US GFS model another.

Now is not the time to get into a discussion on the accuracy of various models. I will just say that the Euro has done a great job with Harvey so far and the GFS a good job. The major variance has been with what happens as Harvey approaches landfall. The Euro has consistently brought the storm barely inland, stalled it then kicked it out to the northeast back over the Gulf. The GFS wants to push it further inland towards San Anton io, then have it move eastward hugging the coast. Well except for yesterday when it took it towards Mexico?? In the end, we are not sure of where Harvey will go once it reaches the coast. The GFS and other models based off of its core model lie along the NHC track. The other half of the models follow the Euro, which has an intact system re-emerge over the Gulf before heading northeast early next week. What actually happens will mean a world of difference with regards to winds and tides for the are from Houston/Galveston to Berwick Bay.

This is why. This is a snapshot from the NAM model, the model used by the US Navy. It shows the position of the “remnants” of Harvey next Tuesday as a strong Tropical Storm due south of Cameron and heading to the NNE. The European Model depicts nearly the same scenario. Even the HRRR, the US tropical specialty model depicts something like this but maybe shifted west by 30 miles. The take away from all of this is we need to watch carefully and see how far inland Harvey’s center makes it. If it gets close to San Antonio, then the GFS is likely on the mark. If it makes it only to Victoria or so before stalling, the Euro camp is likely right. My gut right now lies with the Euro but it not with a great deal of certainty. What we absolutely do not want is Harvey to reach the coast and stall with it’s eye over water! Possible? Sure but not likely right now at least.

All that said, one thing is certain: Everyone from the Houston metro area well eastward into Louisiana is in for a lot of rain. And it really again depends on which of the model solutions verifies as to whether we talk in inches or a foot or more! The NHC has put out a rainfall prediction based upon the GFS course scenario which call for four or more inches of rain from Mobile to Brownsville, with a maximum of nearly three feet of rain near and around the area of initial landfall.

You can see from the image that the Berwick Bay region is predicted to be in the 10-15 inch swath, Cameron could approach 20 inches, and the Houston Mertroplex would be looking at 20-plus inches. Should the Euro/NAM solution be the right one, we would likely elongate the areas of heaviest rain farther to the east by say 75 miles. Bottom line, regardless of the winds and such Harvey brings us, we will be looking at lots of rainfall. Those in Houston who historically flood may need to be thinking about exit routes if waters begin to rise. Harvey will likely be known much more for his rainfall and flooding than his wind damage.

Look for updates over the next couple of days as the future track of Harvey becomes more certain. That will allow us to the north and east of the first landfall to prepare for Harvey Part III, whatever and where ever that may be. Until then, stay safe and stay dry!

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Tropical Storm Warning

By Chuck | Published Monday 19-Jun, 2017

The National Hurricane Center has issued a Tropical Storm Warning for the Louisiana Coast from Intracoastal City to the mouth of the Pearl River. A tropical storm warning means tropical storm conditions, with winds in excess of 39 mph are expected in the warning area within the next 48 hours. In this case we could see those winds and storms within 24-36 hours.

All of this is in reference to Investigation 93L now known as Potential Tropical Cyclone Three. In an effort to stay ahead of the curve, the NHC can now issue watches and warning even when a system is still forming like this one. Two satellite passes earlier today showed surface winds in excess of tropical storm strength associated with the system getting organized north of the Yucatan Peninsula. The models had predicted this system to form as long as a week ago but were unsure when and where it would form or go. Things have become clearer as the system got into the Gulf over the past 24 hours.

This is the latest visible satellite loop from this afternoon and you can see the system trying to get organized in the southern Gulf off of the Yucatan. In the final frames you can see what looks like an exposed closed center. Thatgood news in all of this: this is not likely to become a hurricane despite very warm Gulf waters. Inhibiting the system is an upper-level low pressure area centered south of Galveston. This upper low has brought us the very dry weather of the past week as it cut off from the upper-level flow and churned over the Louisiana-Texas border region. As we have discussed here in the past, upper-level lows bring with them shear that makes it difficult for thunderstorms to grow upward into the atmosphere and wrap around the center.

There is an issue though. The upper-level low is now weakening and pulling off to the southwest towards the Bay of Campeche. So while it will impact the growing tropical system for a while, the impact will lessen over the next day or so. 

In the GOES Water Vapor Loop at left you can see the growing tropical system covering the eastern half of the Gulf. To its west is a section of browns and blacks. That is the dry air associated with the upper-low. Notice a couple of things about the upper low: first of all, it is moving now and moving to the southwest; and second, it is “filling” or falling apart. Notice how the clouds with the tropical system are moving westward, while moisture over Texas, whiter colors pushes in from the west. Finally, see all of those white streamers flowing in from the lower left. These are all signs the upper-low and its shear will soon be less of a factor, allowing a more concentric system to  form.

In general, the models are indicating a system with winds no more than say 50 mph. In fact the NHC is being a bit more conservative with top winds only reaching 45 mph. But this is one system where winds are the least of our worries. PTC #3 is a massive rain maker. And with some of the models indicating it may slow as it approaches the coast, we could be talking about dangerous amounts of rain. Tropical storms have historically been some of the most intense rain makers of all tropical systems, with some dumping up to 30 inches of rain. We are not talking about those kind of numbers here, but double-digit rain amounts are likely near where the center crosses land and to the east of that.

Normally, we would feel pretty good about being on the western side of the warning area. But it is more related to the lopsided nature of the system than the potential landfall site. Best guess is the center will come inland just to our west. That is purely a guess but probably a good one. We will in all likelihood be on the wet side of the storm. And if the system manages to wrap up and become more organized, the Tropical Storm Watch from Intracoastal City to High Island Texas may be upgraded to a warning as well.

As you can see from the latest model runs, we are pretty unlikely to avoid the effects of this system. Thankfully, it will be a rain maker and not a wind machine. It has been a while since we have  had a tropical system impact the Berwick Bay area. So this would be a good time to take care of all of those early season activities and prepare your home and family for what is shaping up as a busy season. I will begin to outline my thoughts on newly formed Tropical Storm Brett in the Atlantic once PTC#3/Cindy is gone. We could be looking at Brett or his remnants in the Gulf by next week.

An Air Force Reserve Hurricane Hunter is currently investigating the Potential Tropical Cyclone Three as I type this blog. If it finds Tropical Storm Cindy has formed out there, I will update this blog with that info. I am also considering moving from these text-based blogs to a YouTube video blog in the near future. Just a heads up. Until the next update, stay safe and prepare!

 

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Matthew a Monster in the Making With an Unclear Path

By Chuck | Published Wednesday 28-Sep, 2016

Tropical Storm Matthew formed this morning out of Invest 97L about 35 miles southeast of St Lucia in the Leeward Islands, or about 2250 miles west-southwest of Berwick Bay. Yes it is a long way off and only a tropical storm with winds of about 60 mph. It is really just starting to spin up and pull the winds and weather in around the center. That said most of the models put the system as a 90-knot hurricane a couple hundred miles south of Jamaica late Saturday. Barring crossing any major landmasses, conditions will be ripe for further intensification and many of the models are predicting a Cat 4 if not a Cat 5 storm in Matthew’s future. A long ways off for sure but the trend will definitely be towards a big one!

So where is this monster in the making headed? That is definitely the $64,000 question this morning and no one has a clue what will actually happen after the weekend. All of the models turn the system more northerly, but in degree of turn they diverge greatly. The major models have landfalls anywhere from the Mexican coast to no landfall at all out in the central Atlantic. So why even predict? In truth, it is a little clearer than that. We will look at that in a bit.

First, let’s look at what is causing all of the variance in the models. In essence it is the wonderful first taste of fall weather that began yesterday and will truly blossom over the next three days. Highs not making 80 and lows near 60 with wonderful dry air and clear skies. It has been a while! But it is an odd scenario generating this wonderful weather. Normally we would see a big deep low pressure center crossing through the Great Lakes, with a cold front trailing to the south followed by a big high pressure area building in its wake. But this time, a piece of the big low is going to split off and drift south over Georgia and stall as it is out of the main upper air flow. Eventually, it pulls out to the north ahead of the next front sometime over the weekend. It is that cut-off low which holds the key to where Matthew will head. If the low pulls out quickly and weakens with high pressure rushing in to replace it, the Gulf is definitely in the cross hairs. If the low is stronger and/or slower to pull out, it is Florida and the East Coast under the gun. Here are the two model ensembles of potential tracks from the two top models in the world. Courtesy of Mike’s Weather Page, by the way. Not exactly a match!

On top is the European (ECMWF) Model for the next 14 days. On the bottom is the US (GFS) Model for the same period. As I explain below, interpreting ensembles is an art. But basically, the two top models in the world have very different ideas. Ignore all those  squiggles and look at the red outlined cones I have added. You will note I have also ignored the major outliers in each case. For instance, some of the ECMWF runs show the storm going west into Mexico near Tampico. That is highly unlikely at least for now, so I have it outside the cone. But you can see how difficult this is to judge.

As I said, ensemble models are not the easiest to understand. The best analogy I can think of is this. Someone has started cooking a huge gumbo to feed hundreds and just walked off leaving you to you to finish it. All you know is what ingredients went into the pot but not how much of each. Health regulations say you cannot sample the whole gumbo pot to check its flavor until it is completely finished. In fact you can’t taste it at all, even a small sample in another bowl, until you have made your changes to that small bowl. So you take about 20 small samples from the big pot and add a bit of this or that to each, covering all your bases, then taste them to see what needs to be added to the big pot to make it Louisiana good.

That is sort of what the ensembles do. They tweak the potential outcomes to cover all the minor changes which might take place. Unfortunately, we can’t sample them until the very end in this case, when we actually know where Matthew went. However, as we watch each successive model run and see which changes seem to be matching what is actually happening, we learn how to target our tweaks for a narrower cone. But it takes many runs and there are only a couple runs of each a day.

Now I know some of you 😉 You want to know what my gut says and will message me as soon as I say “we just have to wait.” So here it goes but this is a flat out guess and confidence is not high. At the moment, I am leaning towards the ECMWF solution for two reasons. First, the ECMWF, while far from perfect, is the best model in the world. It is the only 4-demensional model out there until the GFS fully integrates temporal data analysis in the near future. Second, the GFS has played this cut-off low as stronger and bigger than appears to be materializing. It would have had us in the mid-70s for highs and mid-50s for lows. That is quite a big miss from what appears to be coming. The ECMWF just appears to have a better handle on the cut-off low right now. If that trend holds, the ECMWF should also have a better handle on the future track of Matthew. But man that is a lot of “ifs.” Too many for any degree of confidence.

Even if the ECMWF scenario verifies, the cone runs from Corpus Christi to Savannah right now, over a thousand miles. Not exactly a pinpoint scenario. But given the extreme uncertainty not just in these models but many others, that wide cone also seems more appropriate to me right now than the narrow GFS cone. But only time will tell. Keep an eye on Matthew as you enjoy our first gorgeous Fall weekend after months of hot and muggy/downright wet weather. By early next week the models will have a better handle on things and we will know who needs to be taking action to protect life and property ahead of Matthew. If this were not complicated enough already, Miche and I are set to fly to Boston over the Columbus Day weekend to visit Evan. So we have a potential of dealing with Matthew either here and up there depending on which track verifies 🙁 Got to love those tropics. For now, just enjoy this wonderful weather!

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There is Invest 92L Coming Into the Gulf as Predicted

By Chuck | Published Friday 09-Sep, 2016

Well after the NHC saw fit to not even acknowledge Invest 92L for nearly a week, it popped up on the NHC Outlook at 4 am this morning with a 10% chance of formation and by noon was up to a 40% chance. Now in all honesty it has been there all along. As we talked about on Sunday, it has had a tough trip through the Caribbean Sea. There was dry air, massive low- and upper-level wind shear, it crossed the massive mountains of Hispaniola, known storm killers, and yet here we are on Friday with a very good chance we will have a tropical depression or storm in the Gulf of Mexico within a day or so.

 wv-gulf-animated

Here are the visible and water vapor imagery from midday. In the visible image on top, you can clearly see there is a closed surface circulation but it is currently displaced from the thunderstorms due to shear from the upper level trough to the north. Note how the clouds off of eastern Florida come down south near the coast then head north over the Bahamas. That is our old friend shear, But she is pulling out to the northeast as 92L moves to the west. As of midday, the system was producing squalls of 30-35 mph in the Florida straits and conditions are conducive to some organization and intensification once it gets into the Gulf.

As to how strong or where it is going to go, we are going to defer those for now. It is a highly complex situation which is going to have to  clarify itself over the next day or two before we know anything with any degree of certainty. In the fight right now is the large upper trough aligned along the Atlantic Seaboard, which will pull off to the northeast. Out just north of Puerto Rico, we have Invest 93L, which is showing absolutely no signs of development and ignored by most models as a dead system. What remains of 93L will sweep up to the northeast and recurve as it follows the upper trough. The spin over Southern Texas is an upper level low moving slowly westward, as it awaits a frontal system which will weep in about four or five days down the line. In between all of that is the triangular area of moisture and storms in the southeastern Gulf, which will be a much more favorable environment for Invest 92L. As the system moves into the area of high pressure aloft over the next day or so, there is a good chance it will become a depression or tropical storm.

What its does then is just not possible to call. The models have no clue right now as they have been sort of told 92L was dead and gone. It will take a cycle or two for them to get a handle on it. Purely looking at the current environment, one sees the weather in the central Gulf pushing up to the northwest towards the central Gulf Coast. That is a likely motion in the short term. But if this system takes its time in the Gulf: well things they will be a changing. A frontal system will swing down around day five or so, which would likely tend to push the system to the west. There are just too many variable to make a reasonable call. Bottom line: I told you Sunday we would need to watch the Gulf by late week and, sorry, I was right. However, I am not real worried about this system at the moment. It will not become a big hurricane. It may go north, northwest, west and even southwest (unlikely though). The biggest threat would be IF it gets swept up to the northwest as a minimal tropical storm and impacts the central Gulf Coast somewhere as a big rain maker. That we do not need. But that is a huge “if” right now, something I rate at less than 20% at the moment. We have a few days to watch and see what is up. As always, I shall keep you informed on my thoughts.

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Here We Go Again

By Chuck | Published Sunday 04-Sep, 2016

First off there is no immediate threat to the northern Gulf Coast from the tropics. So enjoy your long Labor Day weekend and if you are with us here in the Berwick Bay Region, be sure and check out the Louisiana Shrimp and Petroleum Festival. With the southern flow, it has been a wet start to the festival, picking up nearly 5 inches of rain here Saturday with another two days of rain predicted. But a little rain never stopped the fun of of the S&P festival!

All the while, I will be keeping an eye on Investigation 92L just now coming into the Lesser Antilles. Conditions have been pretty rough on the system as it crossed the Atlantic, including the same things we saw with what would become Hermine: Dry Saharan air and dust; along with wind shear at the upper levels. But as of this morning we had an open wave which is showing signs of circulation.

As you can see on the visual loop, what had been an elongated area of thunderstorms, is now starting to wrap up into a more concentrated system with some sort of rotation. This morning, the system was located near 15.1N 105.6W approaching the islands of Dominica and Guadeloupe in the Lesser Antilles. The pressure was near 1005 mb, 29.68 inHg, with winds sustained near 30 knots over a large region. The radius of max winds is about 120 NM and radius of circulation about 200 NM. It is not a very organized system at this time and I honestly do not expect it to do a whole lot for most of the coming week. The NHC puts chances of development into a tropical storm at 20% in 48 hours and 30% in five days. I  agree with that but for different reasons.

Just as with Hermine, this system is not going to have an easy way through the Caribbean Sea. It is going to be up against more dry air, a fair amount shear, and at times a close proximity to land. For that reason, many of the models have it just disappear over the next couple of days. Sort of like what they did with Hermine. The major models, the US GFS model and the European ECMWF model, are having a difficult time with these poorly organized systems in a hostile environment. But if you remember back to the Hermine blogs, there was one model which consistently was right on the mark. It never gave up on Hermine, kept it south of Florida rather than hitting the mainland, then was the only model to throughout target the northern Gulf Coast of Florida rather than areas near Tampa for landfall. It nailed Hermine when others could not even find her.

That model is one you will seldom hear mentioned and when it is mentioned, many do so in kind of laughing manner. It is not a billion dollar mega-model like the GFS and ECMWF, but unlike other less known global models  the CMC does not use the output of the GFS and ECMWF for its data. Rather, the Canadian CMC model uses its own data set and parameters. For some reason, it has a handle on these weak tropical system this year. There in lies the hitch. I’d like to just grab one of those “spaghetti model” images to show you the track, but this model is not often on those images we see on TV and online. I could just put up their link. But model data sights are some of the most confusing places on Earth! Best I could do was a two picture montage of the CMC for the period Sat – Tues of next week (10th – 13th):

Now do you see my concern! This model, which was right on for very similar Hermine, has the new system off the Yucatan next Saturday, right image) as a strong tropical storm (997 mb) and by Tuesday (left image) it is approaching the Louisiana coast just to our west as a 973 mb Category II hurricane. Regular readers know I harp on the fact that even the five day forecasts can be off by up to 300 miles. Often having the system heading right for you this far out means it will surely miss you.

BUT! Considering how well the CMC handled Hermine. It never wavered on making Hermine a hurricane and having landfall moved on the norther Gulf Coast. It was the only model that pointed us in the right direction. What most concerns me at this point is the consistency. Over its last five days, this model has consistently pointed this system at some part of Louisiana by late this week into the next. So we will be watching very closely over the next few days. I think we would all be happy to see the CMC wrong an the big models right on this one.

In addition, this system like Hermine will need to run through some really tough obstacle course if it is to make it to next weekend as an organized system. First, see all that reddish air ahead of the system on the water vapor loop. That is very dry Saharan air and dust. It will have a very negative impact on the system if it gets drawn into the circulation. Tropical system want nice juicy wet air, not this stuff. In addition, if you watch the motion, you see that clouds over eastern Cuba are moving southwest, while those in front of the system are being carried off to the northeast. That is a very narrow upper-level trough which will cause a great deal of shear until it sort of pinches off late week. All the while Invest 92L will be taking a track which brings it near Puerto Rico, Hispaniola, and Cuba, all of which have mountains that tend to break up the circulation. Unfortunately, the forecast track is south of and near, but not over, any of these land masses which would likely be the death knell for a weak system. But the bottom line is that the system will likely stay weak until it enters the Gulf if it makes it that far. But if we do get a Gulf system, we saw with Hermine how quickly an unnamed storm can become a growing hurricane. And this one would have longer over the warm Gulf waters before landfall.

But as I said up front, enjoy the holiday weekend. This system is a long ways off and likely not to do a whole lot of anything quickly. Hopefully, the CMC is wrong and it just gets killed by the dry air and shear. Even if it does hold together we have a week plus to watch and prepare. Either way though, it is a sign the hurricane season is heating up and for the first time in many years, the northern Gulf seems to be in play. I will be watching closely and update as needed.

Happy Labor Day!

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