Tropical storm looking more likely now

As we begin the long holiday weekend, residents of and visitors to the coast of parts of the Southeast may have to deal with a tropical storm. This is not typical of Memorial Day weekend but this year, it looks like we will break the norm.

The latest info from the NHC tells us that the area of low pressure between Bermuda and the Bahamas continues to get better organized, with a 90% chance of further development. That being said, it is hardly doing so at a rapid pace, this is not peak hurricane season with ample warm water around. As it is, we are essentially at the very beginning of the season and the amount of energy available is somewhat limited.

Intensity guidance from the over night model runs showing what would be a tropical storm forming over the next couple of days just off the Southeast coast

Intensity guidance from the over night model runs showing what would be a tropical storm forming over the next couple of days just off the Southeast coast

As the low moves towards the warmer waters of the Gulf Stream, there is a chance for it to strengthen and it could become a tropical storm before reaching the coast. The other scenario is that the low remains loosely organized and resembles more of a subtropical storm with winds spread out away from the center. Most of the computer guidance, some of which simulates the structure of tropical systems, indicates that this will in fact become purely tropical in nature – meaning that there should be a well defined center with organized bands of showers and thunderstorms closer to that center. This is what most people are used to seeing and I think that is what will happen.

Most of the track guidance suggests a landfall somewhere in South Carolina over the weekend. This means the obvious chance of heavy rain, some gusty winds and a churned up Atlantic. Beach-goers need to be especially mindful of local conditions – rip currents are part of the over all package of hazards that tropical systems bring with them. Do not underestimate the power of rough surf conditions, heed local surf advisories and keep the little ones very close to shore.

As far as other impacts, it’s too soon to know how much rain and who gets it. Once the storm forms and models get a better handle on its structure, that info can be fine tuned. You can bet on some locations receiving a few inches of rain but this is not the set up that we saw last October when hurricane Joaquin was off shore, peeling off insane amounts of moisture. There will be potential for heavy rain, but nothing like what we saw last fall.

The NHC mentions that the Hurricane Hunters will be investigating the low later today. Once we get the info, I will post another blog update here along with a video discussion for our app, Hurricane Impact, and on our YouTube channel.

M. Sudduth 8am ET May 27

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NHC showing likely development of “something” as we head in to the weekend

NHC 5-day outlook map showing the high chance of development for invest area 91L off the Southeast coast

NHC 5-day outlook map showing the high chance of development for invest area 91L off the Southeast coast

The area of interest off the Southeast coast, now known as “invest 91L”, is slowly getting better organized. The NHC has increased the chances of development in to the high category as we head in to the big holiday weekend.  But development in to what, exactly? That remains to be seen.

According to the latest statement put out this morning, a tropical or subtropical storm could form from the system as it approaches the coast this weekend. Let’s take a look at the differences between the two possible scenarios:

A tropical storm is what we are most used to hearing about. Winds are more or less concentrated around a well defined area of convection or thunderstorm activity close to the center.

A subtropical storm is more like a hybrid storm that has some tropical characteristics while also displaying some non-tropical signs as well – such as having winds and energy spread out over a larger area and more loosely defined convection. In other words, a subtropical storm hasn’t quite bundled all of its energy around a distinct, warm-core center like we are used to seeing with purely tropical systems, especially hurricanes. Subtropical storms usually transition completely in to classical tropical storms if they remain over warm water long enough.

In the case of 91L, right now, it remains spread out and not very concentrated, therefore, development has been slow. As long as this continues, we won’t see much more than a nuisance rain maker for the Carolina coast this weekend. However, water temps in the Gulf Stream, which is still to the west of the developing storm, are quite warm and it is possible that we will see a pure tropical storm form which would mean more wind, rain and rough surf conditions for the coastal areas that it impacts.

The good news is that none of the model guidance suggests anything too strong coming from this. After all, it is only late May, not September. That being said, we should never ignore a festering tropical feature that is so close to land. If you have plans along the beaches from Georgia to Cape Hatteras, keep them, but be aware of this feature and the potential for heavy rain and some gusty winds. The other hazard that would concern me is rough surf. Water temps along the beaches are still sub-80F but this will not keep people out of the water this weekend. Watch for local conditions to change including the chance of increased rip currents. Remember, tropical storms have the potential to be deadly if people don’t understand the local impacts. Keep an eye on the kids if they plan on heading in to the ocean in the affected area during the long holiday weekend.

I will post a video discussion concerning 91L later this afternoon followed by a blog post update here this evening.

M. Sudduth 9:50 AM ET May 26

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Texas deluge as tropical moisture aimed at Lone Star State

NHC graphical outlook and the potential track area of invest 91L

NHC graphical outlook and the potential track area of invest 91L

A lot has been made already about the presence of invest area 91L. After all, it is hurricane season and we do have an area of interest to monitor in a region that hasn’t had much activity over the past few years. In fact, a grand total of zero hurricanes have made landfall in Texas since 2008 – Ike was the last. While there is nothing at all to suggest that 91L will become a hurricane, it does raise a few eyebrows and for good reason: the rain threat.

May was an absolutely stunning month for rain in parts of Texas. Houston alone set records and had flooding issues. Farther inland, areas such as Austin, San Antonio and Wimberley experienced flooding which resulted in loss of life and significant damage. The power of water is often unappreciated until it changes lives and alters the landscape.

Enter 91L in to the picture and the NHC’s potential track area as seen in the graphic and you can see why Texans are probably a little more concerned about this system than they might be otherwise. None of the intensity guidance suggests anything more than a lopsided, weak tropical storm. Nothing to worry about, right? Wrong. Tropical cyclones, this includes tropical depressions and tropical storms mind you, have four main hazards that they can hit you with: wind, storm surge, rain and tornadoes (downburst winds too). The majority of the public responds well when the forecast suggests 150 mph winds are coming. Sadly, storm surge, as lethal as it is, seems to be ignored (see Katrina, Ike and Sandy).

That leaves us with rain, the most abundant of the tropical cyclone hazards and yet it is the most ignored and least understood by the average person. We think of rain as cleansing and necessary to sustain life. However, too much of it at once or even over several days has a drastic effect on life as we know it.

Only a few inches of rain in a short period of time can overwhelm flood control systems in large metro areas such as Houston. If the rain keeps coming, everything literally cascades in to a total disaster, often stranding hundreds of people who didn’t seem to know better. Even after years of “turn around, don’t drown” people will think they are immune to the laws of physics and do something that defies logic. All because they didn’t respect the power of rain and freshwater flooding.

What does all of this have to do with 91L? Plenty. I think this is an opportunity for people in the region, mainly Texas, to show that they have learned from past experiences. Allison in 2001 was quite a while ago, I’ll give them that. But the May floods were, well, in May – just a few short weeks ago.

There is the potential for what ever becomes of 91L, whether or not it attains tropical storm intensity, to drop a lot of rain over areas that simply don’t need it – at least not in the quantities that some forecasts are showing.

The good news is that upper level winds should keep 91L from becoming much more than a rain threat. This will minimize the amount of wind and surge impact to the coast. However, any onshore flow in areas such as Bolivar Peninsula could lead to over wash – that area is flat with little to no dune protection.

The bad news is that the Gulf of Mexico is ripe with moisture. Water temps are running above normal with actual temps close to the upper 80s along parts of the northwest Gulf. This will lead to an incredible amount of precipitable water being lifted in to the atmosphere and wrung out over Texas next week. Flooding is almost a certainty but exactly where is impossible to pinpoint.

It is going to be important for people in the region to monitor their local news outlets and reliable social media sources for updates. This is going to be a constantly changing situation and a lot will come down to how much rain falls over a certain area and for how long. Since that cannot be forecast with any real accuracy this far out, keeping up with the latest from the National Weather Service and your local TV meteorologists will be important in keeping you and your family safe.

I highly recommend using weather.gov and then inputting your ZIP Code. The return page will have a ton of useful links and information, including the latest watch/warning package and any special statements. It’s all right there at your fingertips – use it!

TS Carlos tracking map from the National Hurricane Center

TS Carlos tracking map from the National Hurricane Center

Meanwhile, Carlos is a tropical storm now just off the coast of Mexico in the eastern Pacific. The forecast takes the storm inland between Tuesday and Wednesday while strengthening it again to hurricane strength. Again, as with 91L in the Gulf of Mexico, the biggest issue with Carlos will be the potential for flooding rain. Certainly hurricane force winds are an issue but with a slow moving tropical system the rain is probably the larger concern at this point. Fortunately, the proximity of Carlos to land should keep it from intensifying much more than it is now, fluctuating back and forth between tropical storm and hurricane strength. Once inland in a few days, its moisture will spread over the interior portions of Mexico further extending the rain and flooding threat to that region.

I will have continuing coverage of 91L and Carlos tomorrow and via my video blog discussions now available through our YouTube channel. Follow and subscribe to the channel here: HurricaneTrack YouTube channel

M. Sudduth 12:15 PM ET June 14

 

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Critical week ahead for parts of the Southeast

Computer guidance has shifted west over night, resulting in a track that poses a threat to the Carolinas later this week

Computer guidance has shifted west over night, resulting in a track that poses a threat to the Carolinas later this week

This week is probably one of the worst weeks out of the entire year that a potential hurricane could threaten the United States. It’s coming up on Independence Day and a huge monkey wrench is likely to be thrown in to the plans of thousands who are wanting to relax at the beach. While nothing is etched in stone, far from it, the chances seem to be going up that something rather unpleasant is in the making as we move through this all-important week.

The issue is, of course, 91L and what will very likely become TS Arthur. The NHC continues to indicate a high chance of development over the next few days.

As of early this morning, the area of low pressure was situated to the east of Florida, about the same latitude as Melbourne and vicinity. So far, organized deep convection remains limited. It appears that northerly winds are continuing to blow over the circulation, injecting some dry air while keeping a lid on tropical thunderstorm formation. However, all indications are that this pattern will change and we will have a tropical depression before too long.

At this point, the forecast guidance is in pretty good agreement that a tropical storm will form and move northward, actually somewhat west of north for a time. Then, the crucial turn to the northeast will commence ahead of an approaching trough swinging down from the upper Midwest. This acts like a soccer player kicking the ball (Arthur to be) out to sea. Well, it’s more complicated than that, but in keeping with current sports news, I thought the soccer analogy worked. The idea is that the supposed-storm would be pushed out to sea at some point – when this happens is very important.

The overnight runs of most of the models indicate that there is a good chance that the system could move over parts of extreme eastern North Carolina. To be fair, there is also a good chance the center remains just offshore. However, we should all know by now that the center is not the only area to watch – effects can reach out 50 to 100 miles or more from the center. We’re talking rip currents, bands of heavy rain, increasing winds and seas and the possibility of tropical storm or even hurricane winds affecting some part of the North Carolina coast. I do not say this without backing it up. The SHIPS intensity model, often cited in NHC advisories, brings the system to hurricane strength – so this needs to be considered. Add to the complication the fact that intensity forecasting is where the least amount of skill lies. Do not gamble on this being a weak, sheared storm with little to worry about. There is enough room for error that I would not be at all surprised to see this system become a hurricane.

For now, we have a slowly developing tropical cyclone just off the Florida coastline. That region will be the first to feel impacts. Higher surf, rain bands and an increase in wind will likely put a damper on vacationers along the east coast of the Sunshine state for a day or two. After that, we need to wait and see what develops and take it from there.

People along the Southeast coast are generally hurricane savvy. The one thing that concerns me is the crowds of people coming in to the region from some inland state and thus having zero hurricane experience. While I may be jumping too far ahead, this is something to consider since we are coming up on a massive beach holiday. This is not going to be “fun” or “exciting”, not in a good way. If what could be the season’s first storm and/or hurricane comes close enough to the coast, people need to be ready or the results could be very rough to deal with.

I will post another update on this developing situation later in the afternoon. I’ll also have the daily video blog posted to our app, Hurricane Impact, by 4pm ET. Follow along with the app which is available for iOS devices and Android. Simply search Hurricane Impact and stay connected where ever you are.

M. Sudduth 8 AM ET June 30

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