Complicated forecast for 99L, easy one for 90L

Convection or thunderstorm activity has increased substantially over night with 99L. You can also see here that invest area 90L is well on its way to becoming a tropical depression.

Convection or thunderstorm activity has increased substantially over night with 99L. You can also see here that invest area 90L is well on its way to becoming a tropical depression.

As I mentioned yesterday in my blog post, it looks as though invest area 99L will continue to struggle and not be much of an issue for land areas anytime soon. However, the recent development of convection or deep thunderstorms suggests that perhaps things are changing, even if only a little bit right now.

The very latest info from the NHC indicates that development chances are going up slightly – now up to 50% in the five day time frame. It appears the warmer sea surface temperatures and a better overall environment are slowly playing in to favor of this system developing.

One aspect that I cannot get over is the large size of the overall envelope of energy with 99L. It is not a small, weak and fragile tropical wave. It’s quite the opposite in fact with a large area of circulation and deep precipitable water profile. What this means is that this feature is not just going away despite the marginal conditions in the atmosphere. As we have seen in the over night hours, convection actually began to increase and persist with 99L and this morning, the satellite shot indicates continued slow organization. If this continues, we may have something to deal with in the coming days as it moves generally WNW towards the Caribbean Sea. Interests in the northern Leeward Islands, Puerto Rico and Hispaniola need to monitor 99L closely. At the very least, it could bring periods of heavy rain and gusty winds as the week progresses.

5 day tropical weather outlook grpahic showing the likely development areas and tracks for 99L (orange) and 90L (red)

5 day tropical weather outlook grpahic showing the likely development areas and tracks for 99L (orange) and 90L (red)

The longer term outlook for 99L is tough to call right now. So much is based on whether or not it goes on to fully develop in to a tropical depression or a storm. Generally speaking, the weaker and shallower in the atmosphere a system is, the farther west it tracks under the low level flow pattern. For now, the NHC is showing a potential track area extending up in to the Bahamas by later this week. There are some indications that the track could be farther south but we will have to wait and see about that. Very warm water temps await this system and if conditions improve aloft, it could be an interesting week ahead with not much time to prepare should this threaten land areas from Florida northward to the Carolinas. While this is not indicated by any particular solid forecast right now, it goes without saying that the closer this gets to the U.S. the shorter the time frame for reacting will be.

As for the short term, I want to emphasize again that this large wave energy should bring heavy rain and squalls to portions of the Caribbean Sea over the next few days. Do not count 99L out just yet. It’s late August, water temps are very warm and we have a large system heading westward. Let’s not get caught off guard.

Meanwhile, what should become the season’s next hurricane, and a strong one at that, is developing in to a tropical depression right now far out in the eastern Atlantic.

The NHC should begin advisories on TD7 later today. The model guidance is in excellent agreement that it will strengthen quickly in to TS Gaston and eventually become a hurricane. I see nothing to suggest that this will ever affect land but it will add to the seasonal ACE score, something that is tracked to help size up the quality of the storms/hurricanes that form.

In the eastern Pacific, a pair of disturbances well off the coast of Mexico both have a shot to develop as they move west to west-northwest out in to the open Pacific. No other areas of concern are seen over the next several days for Pacific Mexico or the Baja peninsula.

I’ll have more here in my daily video discussion. Also, you can follow all of my updates using our app, Hurricane Impact, available in the App Store. This blog, social media posts, video updates and field mission reports/data all goes in to the app. We’ve had it since 2012 as a great way to keep up with HurricaneTrack.com info while on the go. Search “Hurricane Impact” on the App Store.

M. Sudduth 8:15 AM ET Aug 22

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Plenty to monitor over the next several days but beware of “scary maps”

NHC map showing potential for development in the eastern Atlantic, spreading towards the Caribbean, as the days progress

NHC map showing potential for development in the eastern Atlantic, spreading towards the Caribbean, as the days progress

We have several areas to monitor in the Atlantic Basin and one area in the east Pacific. Fortunately, none pose a direct threat to land for the time being but one area, in particular, warrants close scrutiny in the days ahead.

First up, tropical storm Kay in the eastern Pacific. Not much to say here except that it will weaken as it tracks well off of the Baja peninsula and eventually turns westward over cooler water. I do not see any appreciable impacts from this storm for the southern Baja except some added moisture. Once Kay dissipates early next week, that should do it for the time being in the eastern Pacific with no additional areas of development seen.

Next we have tropical storm Fiona in the open central Atlantic. Top winds are only 45 mph with limited deep convection noted on satellite imagery. Overall the dry mid-level air, partly due to the incessant Saharan Air Layer (SAL), is keeping Fiona from strengthening and this will likely remain the case over the next five days. In fact, the NHC is forecasting the storm to weaken as it moves farther to the north and west, well to the southeast of Bermuda. While I do not anticipate any issues arising from this storm, we never just ignore them until they dissipate or are headed away from land areas.

Of greater concern, especially for the eastern Caribbean islands, is invest area 99L deep in the eastern tropical Atlantic. The NHC gives it a 50% chance of becoming a tropical depression or stronger within the next five days.

The overall envelope of energy with the tropical wave is impressive. The large sprawling size makes me believe that development will be gradual at best. The SAL is far enough to the north to allow for slow but steady organization and it should go on to become the next named storm. If so, it will be “Gaston”.

Computer models are very aggressive with strengthening, perhaps a little too much so. Most of the intensity guidance suggests 99L will become a hurricane but I think its large size and overall state of the deep tropics will limit intensification until later in the period.

Interests in the Lesser Antilles should be watching 99L closely. Almost all of the track models indicate a general westward movement in to the eastern Caribbean early next week. As we have seen time and time again, it does not take a strong tropical storm or a hurricane to cause life-threatening flooding. The people in parts of Louisiana know this all too well and we need only to look back at Erika last season as a reminder for the Caribbean. There’s not much you can do to prepare for heavy rain, just being aware and making sure there is safe haven is at least something as opposed to nothing.

There is no doubt going to be a lot of speculation about where 99L and its eventual transition in to a tropical storm (or hurricane) will end up. In today’s world, computer model forecast maps can be shared with literally millions of people at a moment’s notice. Under the wrong context, this can be harmful. Not everyone has the weather geek know-how to realize that a 5, 7 or 10 day map has extreme limitations. On top of that, graphs showing intensity will only lead to more anxiety when it is probably unwarranted.

My point is, we are likely going to have to deal with a tropical storm and possibly a hurricane some time next week. The first area of concern is for the eastern Caribbean Sea. Beyond that, it’s wait and see just like it has been since I began this site back in 1999. Sure, the Internet has made things a lot faster, more weather models are available and so forth but with great access comes great responsibility (sorry Spiderman, had to borrow your uncle’s catch-phrase). Staring at a map that shows a giant hurricane on it 10 days out is not helpful to most people. If you see such things in social media, say to yourself, “Hmmm, guess I better keep an eye on that one”. Worrying about it this soon is futile – instead, maybe do a little more to prepare in case this, or any future storm/hurricane, comes your way. I’ve said my piece on this issue but just know, it’s coming (the scary weather maps) and you’ve been warned. Be smart and don’t spread the fire by sharing such images.

Last in my list of things to cover, the NHC has highlighted the area just off the African coast, out in to the eastern Atlantic by a few hundred miles for possible development next week. This too is just something to monitor but hey, if you live in the Cape Verde Islands, you could be impacted by squally weather as this tropical wave moves by.

It’s getting towards late August and we were told this hurricane season could be the busiest in four years. So far, it has generally lived up to that expectation. We are headed in to a busy period with a lot to keep up with. Considering the world around us and the inherent, constant distractions, it will be more important than ever to stay aware and be ready….just in case.

I’ll have more in my video discussion later this afternoon followed by another blog post in the morning.

M. Sudduth 2:30 PM ET Aug 19

 

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Tropics about to get quite busy as we head deeper in to August

Satellite image of the eastern Atlantic where TS Fiona is moving out over open water. We are also watching for more tropical wave energy just off the coast of Africa for possible development.

Satellite image of the eastern Atlantic where TS Fiona is moving out over open water. We are also watching for more tropical wave energy just off the coast of Africa for possible development.

There are indications that things are going to be busier and busier over the coming days and weeks as far as the Atlantic Basin goes. You may recall that the east Pacific was producing storm after storm, with a few hurricanes thrown in too, back in July? While I do not see that much activity coming, I do think there is potential for several more development areas over the next two weeks.

First up is tropical storm Fiona. Obviously this system poses no threat to land and probably won’t as it moves generally northwestward over the open Atlantic.

The combination of dry mid-level air being ingested from time to time and some stronger upper level winds will likely keep Fiona from becoming too strong. Water temps gradually increase out ahead of the storm and if the background environment changes enough, the chance for it to become a hurricane is there. However, this would only affecting shipping lanes and add to the ACE score for the season. I just don’t see any reason right now to be concerned with Fiona directly impacting land.

As we watch Fiona, we also need to monitor activity just off the African coast for possible development down the road. Computer models are suggesting the possibility of additional development from one or two more tropical waves over the next five to seven days. This would be the most active the MDR or Main Development Region has been for quite some time. It also fits in perfectly with the time of year we are in as the latter part of August tends to see an increase in potential for development across much of the tropical Atlantic.

Meanwhile, the east Pacific will likely have a new named storm before too long. The NHC is tracking invest area 97-E well off the coast of Mexico. Conditions appear favorable for this to continue to develop and become a tropical storm as it moves northwest but off shore of Mexico and the Baja peninsula.

I will have more in my video discussion which will be posted here and to our app, Hurricane Impact, later this afternoon – followed by more blog coverage here tomorrow morning.

M. Sudduth 10:20 AM ET Aug 18

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The “real” hurricane season is about to begin…maybe

We should all know by now that the official hurricane season is June 1 – November 30. That’s what the powers that be designated as the most likely time to see tropical storms and hurricanes form in the Atlantic Basin. Within that 6-month window (hard to believe hurricane season takes up half the year) there is a pronounced uptick in activity that many refer to as “the real hurricane season”. It usually begins around mid-August and lasts until roughly the end of October. Some years, like 2005, are exceptional for the amount of activity spread out over the entire season. Other years, like 2013, it seemingly never comes. On average, however, today is generally thought of as the beginning of the real hurricane season and if it’s going to be active, this is when we begin to find out.

Before jumping in to what to look for in the coming days and weeks, let’s examine a few of the larger pieces of the puzzle that could help to shape the peak months of the season.

Sea surface temperature anomalies showing the obvious difference between 2015 and 2016 with a much colder tropical Pacific this year along with a warmer tropical Atlantic as well

Sea surface temperature anomalies showing the obvious difference between 2015 and 2016 with a much colder tropical Pacific this year along with a warmer tropical Atlantic as well

ENSO or El Niño Southern Oscillaion

This one is quite simple. El Niño tends to kill Atlantic hurricanes, especially in the deep tropics. It did a great job of that last year (Joaquin formed outside of the deep tropics from a non-tropical area of low pressure). The prediction was for there to be no El Niño this season and that has come to pass. In fact, the tropical Pacific is generally a lot colder now than it was last August. This is regarded as a plus for Atlantic hurricane development. While we are not seeing a true La Nina just yet, at least according to official standards, the Pacific has cooled significantly and you can see this clear as day in the two images I have posted here.

Atlantic Sea Surface Temperatures

While the Pacific has cooled, most of the tropical Atlantic, Caribbean and Gulf of Mexico has warmed to above normal levels. In fact, areas in the western Atlantic are as warm as I have ever seen them with anomalies (departure from normal) running several degrees above the long term average. This provides more fuel for hurricanes but not just at the surface. The upper ocean heat content is also very rich right now in areas close to land. The amount of available energy is somewhat astounding and if a hurricane comes along under the right atmospheric set-up, we could see intense development and not the weak, lop-sided storms we’ve observed in recent years.

Note that warm water alone does not yield hurricanes. It is certainly a must-have ingredient but it is not the catalyst by itself. Despite the record warm water temps, other factors need to be favorable or nothing of note happens. I’ll go over some of that as I continue on…

Wind Shear

Shear analysis showing favorable (green) in the east Atlantic but quite unfavorable (red) in the Caribbean and Gulf of Mexico

Shear analysis showing favorable (green) in the east Atlantic but quite unfavorable (red) in the Caribbean and Gulf of Mexico

Shear analysis showing favorable (green) in the east Atlantic but quite unfavorable (red) in the Caribbean and Gulf of Mexico (click to enlarge)

Wind shear or the change of wind direction and/or speed with height in the atmosphere is a very important piece of the hurricane puzzle. Too much strong wind blowing against a developing or already developed hurricane usually leads to its demise. In 2005, for example, shear values over the Gulf of Mexico were close to zero for much of the season, especially when Katrina and Rita formed. These were ideal conditions, hard to duplicate (thank goodness) but it does happen.

Right now, the signal is mixed. Shear values over the eastern Atlantic are favorable for development. However, for the time being, the farther west one looks, the more the shear increases, literally screaming out of the west across the Gulf and Caribbean. This is a deviation from what we’ve seen for a good chunk of the season as shear has generally been favorable until recently. The pattern right now is such that anything tracking west will run in to this shear zone and be torn apart – unless the pattern changes, which it can but so far, I don’t see it doing so right away. This is something we will have to monitor almost daily since things can evolve rather quickly and change the outcome in a hurry.

Overall, compared to 2015 especially, shear is down and for the most part, this is a favorable sign for Atlantic hurricanes.

Instability

Tropical Atlantic vertical instability (blue line) is quite below where it should be (black line)

Tropical Atlantic vertical instability (blue line) is quite below where it should be (black line)

The lack of an unstable atmosphere is something that has been in place for several years in a row. Simply put, warm, dry air has been capping thunderstorm development in the MDR or Main Development Region of the deep tropics. Moist air, filled with energy, needs to lift in to colder air, if warm air is present over warm air, then there is little in the way of convection and thus we don’t have showers and thunderstorms developing which are THE mechanism for developing hurricanes. No convection = no hurricanes. For some reason, dry air, even when the famed SAL or Saharan Air Layer is not present, has been dominant for the past several hurricane seasons. This mid-level layer of stability has resulted in very little action in the MDR – the area between Africa and the Lesser Antilles. If memory serves, I think that Ike in 2008 was the last of the long-track hurricanes. Others such as Irene in 2011 struggled despite forming in the MDR. It is something new that we’ve been seeing and needs further study since it seems to be rather persistent.

So far this season, instability has been generally lacking again across the tropics and unless this changes, tropical waves will struggle until reaching more unstable air farther west.

This brings up an interesting scenario. If the tropical waves struggle out in the open Atlantic, everyone seems happy and safe since hurricanes have a hard time in dry air. Ok, well, what happens when those same tropical waves struggle all the way to say, 70 degrees W longitude? At that point, they blossom under a much more favorable environment and become hurricanes much closer to land areas. Earl was a classic example of this. It “waited” until right before landfall and sprung to life. Ask the people in Belize and southern Mexico about the “struggles” of the parent tropical wave that became Earl. Yes, it could have developed much sooner and become an intense hurricane but my point is, the later they wait to develop, the better the odds they hit land. So while the dry air may be impeding development out in the deep tropics, don’t be fooled by people who say this is a uniformly good thing. Sometimes the opposite is true.

Sea Level Pressure

Air has weight. We call this air pressure. High pressure squashes cloud formation generally (especially convection or thunderstorms) and low pressure tends to foster storminess. In the tropics, lower surface pressures helps to make the air slow down and converge, allowing it to pile up and promote thunderstorm development. Higher surface pressures typically doesn’t allow this set up and is thus a negative factor for development. So far this season, surface pressure in the deep tropics has been higher than normal more so than lower than normal. It’s not outright terrible for development but it hasn’t helped much for sure. This, like shear values, needs to be monitored on a weekly basis as it can change and lead to a burst of activity when pressures lower.

Going forward – the next 60 days

If you add it all up, the ingredients are there for a busy hurricane season but not so much so that it will set records. There are still other aspects that are more difficult to go in to or that I myself don’t quite understand well enough yet. However, the larger, more obvious pieces to the puzzle indicate enough positives for an active season to warrant concern – more so than the past few seasons for sure.

For me, the single ingredient that worries me the most is the very warm water in the western Atlantic. While it is obvious that if no hurricanes track in to this warm water it won’t matter, what if they do? Remember what I said about the weak, struggling tropical waves? If even a few survive to form later and farther west, it could mean they make it in to the area of very warm water. It’s something we will just have to wait and see about.

So that brings me to the current set up.

Current area of interest, 98L, southwest of the Cape Verde Islands

Current area of interest, 98L, southwest of the Cape Verde Islands

Right now, we do have a strong tropical wave in the deep tropics. It emerged from the African coast a couple of days ago and is moving generally westward. The NHC gives it fairly low odds of developing further but some of the computer models are more favorable for continued development.

Warm water is plentiful but the dry air is not far away from the system. If it manages to survive the next few days, shear awaits unless it tracks north of the Caribbean. It’s going to be one of those “wait and see” situations. However, I find it ironic and perfectly timed since today is typically the beginning of when we look out across the tropical Atlantic for signs of activity. Right on cue, we have something to watch. Whether or not it becomes noteworthy remains to be seen.

The next 60 days will probably define the hurricane season. Will it end up being a non-event for U.S. interests once again? Or, will the 10+ year streak of no category three or higher hurricanes making landfall come to an end? The stage is set, maybe not for an award-winning performance so to speak, but certainly more so than in recent years. Right now, it is still quiet. There is time to prepare if you feel so inspired. The historic flooding in Louisiana should serve as a reminder that we’re not talking about only wind or surge here. It’s hurricane season and the peak months are just beginning. I’d say “be ready” because it sure seems like all that warm water won’t go untouched.

I’ll have more on the current goings on in the tropics with my video discussion to be posted later this afternoon.

M. Sudduth 9:20 AM ET Aug 15

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Deep tropics closed – so we look west, closer to land

Recent satellite photo showing the areas of interest, and the shut-down eastern Atlantic

Recent satellite photo showing the areas of interest, and the shut-down eastern Atlantic  (click for full-size image)

Another large, suppressing surge of dry, stable air is moving off of Africa as of late and this will all but shut down the chance for development in the deep tropics – at least for now. With the eastern Atlantic out of play, where might we look for possible development over the coming days? The answer: farther west, closer to land areas.

Before I get in to what may be coming down the road, let’s look at the latest on Earl, which is still alive and somewhat well in the Bay of Campeche.

After making landfall in Belize, Earl managed to remain intact as a tropical storm as it moved across the Yucatan peninsula. It is now situated over the extreme southern portion of the Bay of Campeche and remains at tropical storm strength. The main threat to land will be continued heavy rain along with some gusty winds. The storm will make landfall again this evening in Mexico and begin to dissipate.

Something interesting will happen after landfall with Earl. It seems that energy from the storm will survive the terrain of Mexico and merge with a disturbance over the southeast Pacific, just off the coast. The NHC indicates that all of this will result in the formation of a low pressure area that is likely to become a tropical depression over the next few days. Since this will be happening so close to land, interests along the Pacific side of Mexico should be monitoring closely. Heavy rain is likely and eventually a tropical storm may form and affect the southern Baja peninsula.

Meanwhile, a complex situation is developing in the northeast Gulf of Mexico that bears watching. The NHC mentions that a trough of low pressure is forecast to develop over the warm waters of the northeast Gulf this weekend. This focal point for showers and thunderstorms could lead to the potential development of a tropical depression at some point. The longer it remains over the water (and farther out from land) then the higher this chance becomes.

Rain forecast for the next seven days showing an alarming amount for portions of the northeast Gulf Coast region. This will change and evolve over time but this gives you an idea of how much is forecast by the computer models.

Rain forecast for the next seven days showing an alarming amount for portions of the northeast Gulf Coast region. This will change and evolve over time but this gives you an idea of how much is forecast by the computer models.

One thing that seems almost certain is that an incredible, dangerous amount of rain is setting up for portions of the Gulf Coast states – mainly from southeast Louisiana eastward in to Florida. In fact, some of the rain totals that are being suggested by computer models are astounding. This is something that needs to be watched very closely. Even if nothing develops in terms of a tropical depression or more, the rain by itself will be a major problem.

Next we have the energy associated with what was once 96L and another tropical wave coming in from the east. While there is not much to look at now, there is some evidence in the computer models to suggest we see development in the southwest Atlantic in a few days. I do not see any indication of anything strong at this point, just something to watch since we are in August and the water temps in the western Atlantic are so very warm.

All in all, it looks to be an interesting few days ahead. The east Atlantic won’t be an issue at all due to the strong SAL or Saharan Air Layer that is dominating the region. So we must look closer to home, so to speak, and with that we do see a few areas of potential trouble brewing. I will add more with my daily video discussion to be posted later this afternoon followed by another blog update here tomorrow morning.

M. Sudduth 11:45 AM ET Aug 5

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