If GFS is right, we are in for a busy week

On Friday, I wrote about the possibility of the season’s first hurricane developing from a tropical wave that was about to emerge from the coast of Africa. At that point, two of the major global computer models, the GFS and ECMWF, were both indicating the development of the tropical wave as it approached the Lesser Antilles.

Now, here we are on Monday and the GFS essentially stands alone. The ECMWF has all but completely dropped the notion of development while the GFS is about as consistent as it can be.

If we follow the evidence we can try to figure out what may end up happening – while also either confirming or denying the GFS and its ability to forecast the development of a tropical storm in the deep tropics.

I have prepared a video discussion covering this intriguing situation by taking a close look at not only the model forecast but also what we see in front of us right now. What does the evidence show? Is there enough there to support the idea of a tropical storm forming later this week? Check out the video below to learn more.

M. Sudduth July 10, 2017

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Models hinting at possible first hurricane of 2017 season

Graphic from Colorado State University's July hurricane season forecast outlook showing the below avg wind shear (blue color) across the MDR for the month of June.

Graphic from Colorado State University’s July hurricane season forecast outlook showing the below avg wind shear (blue color) across the MDR for the month of June. Click for full size.

The update from Colorado State University to the 2017 Atlantic hurricane season forecast made mention of the fact that, during the month of June, sea-level pressures were well below average across the deep tropics – also known as the MDR or Main Development Region. This is the area between Africa and the Lesser Antilles and has seen its share of powerful hurricanes over the decades.

In recent years, however, the MDR has been notably quiet. Dry air, strong upper level winds and generally higher than normal pressures have kept the region much more benign – resulting in far less hurricanes such as what we saw in 2004 with Frances and Ivan, as examples.

This year, it is becoming more and more obvious that the sleeping giant is awakening, so to speak. Water temps across the MDR are above normal, wind shear is below normal and surface pressures are below normal. The result thus far has been the formation of tropical storm Bret last month (extremely rare to have MDR tropical storms in June) and now, most recently, tropical depression four – technically a tropical cyclone though below tropical storm intensity. The only significant mitigating factor keeping TD4 in check has been a large Saharan Air Layer or SAL event that has pushed ample dry air in to the deep tropics, smothering the depression and keeping it from strengthening further. This SAL outbreak is typical for July, having a tropical depression in the MDR is not.

ECMWF model at day 5 from last night's run showing energy or vorticity at the 850mb level of the atmopshere (circled in green). Image courtesy of Levi Cowan - tropicaltidbits.com

ECMWF model at day 5 from last night’s run showing energy or vorticity at the 850mb level of the atmosphere (circled in green). Image courtesy of Levi Cowan – tropicaltidbits.com. Click for full size image.

Now comes the next chapter in this story. Both the GFS and the ECMWF are now indicating the development of a tropical storm originating from a tropical wave that is about to emerge from the African coastline. I want to be clear, the development happens beyond the 5-day time frame but well within the next 10 days. Since both of these global models now indicate this happening, it has my attention. In fact, both models go on to develop the system in to what would likely be a hurricane later on in their forecast periods but again, not at some ridiculous time frame such as 10 to 14 days out – what many consider to be “model fantasyland”.

What concerns me about this is the mere fact that it is still early July, several weeks ahead of the traditional beginning to the normal run-up to the peak of the season and we’re talking about yet another MDR system trying to develop. In other words, if it’s this busy now, when climatology says it should not be, how busy will it be when the natural background state is inherently favorable? That usually sets in around August 15-20 and lasts until the end of October.

I make it a point to refrain from being an alarmist – those who have followed my blogs and video discussions know this and I stand firm behind that belief. At this point, I am beginning to worry that this season could end up exceeding all of our expectations in a bad way. The time-tested saying of “it only takes one” remains intact but this is the kind of season where we could be looking at multiple “it only takes one” events. Please keep in mind too that I am not talking about just the United States in terms of impact. The Lesser Antilles are front and center for any action that rolls out of the MDR and west of there we have Puerto Rico, Hispaniola and Cuba. This is the kind of season that could affect a lot of people across the Atlantic Basin and in areas that can least afford such bad luck.

I am going to say it, the signs are ominous right now. We’ve gone a long time without experiencing a category three or higher hurricane in the United States. They’ve also been somewhat rare elsewhere with the exception of Matthew and its devastating impacts on Haiti, eastern Cuba and the Bahamas last year (Joaquin in 2015 also impacted portions of the Bahamas). It is time to take notice and be ready to act.

Needless to say I am going to be watching the evolution of this next potential system very closely over the coming days. Perhaps it is just a blip in the models and subsequent runs will drop the storm/hurricane completely and we can all breathe a sigh of relief. I will post a detailed video discussion concerning this potential development later this afternoon once the morning model runs complete and are available.

M. Sudduth 7:45 AM ET July 7

 

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Karl to be focus of attention over next several days

Satellite image showing TS Karl which is currently sheared quite a bit along with a new tropical wave emerging from the coast of Africa. Click for full size image.

Satellite image showing TS Karl which is currently sheared quite a bit along with a new tropical wave emerging from the coast of Africa. Click for full size image.

The main area to watch this weekend and in to next week will obviously be tropical storm Karl. While the odds are in favor of it turning away from the United States at some point, there is nothing that tells me this is a sure thing.

Right now, Karl is dealing with strong upper level winds and a dryer than normal mid-level portion of the atmosphere. Despite these inhibiting factors, deep thunderstorms are trying to develop in association with the vigorous low level center. Each time a burst of convection manages to pop up, the strong winds blowing against the storm quickly removes the clouds and pushes them back to the east. This bursting pattern as we call it will not lead to any appreciable strengthening but will keep the storm moving west and even south of west this weekend.

As we get in to early next week, both the intensity and the steering of Karl will become very important. The global models seem to be waffling back and forth between making this a hurricane and doing very little with it at all. Other intensity guidance suggests some strengthening next week but the extent of that is still an unknown. Water temps are plenty warm but the upper level winds are questionable. The recent uptick in shear across the Atlantic could remain in place, keeping Karl weak. If the pattern changes and the shear relaxes then it’s likely that Karl will become a hurricane.

As of now, it looks like the Lesser Antilles will not have any direct impacts from Karl. It should track well to the north of the Caribbean and be positioned somewhere between Bermuda and Puerto Rico in about five days. After that, it’s a question of whether or not a trough of low pressure passing by to the north of Karl will be enough to lure it out and drag it back in to the open Atlantic. It stands to reason that the weaker Karl is in to next week, the further south and west it will track. Then, as the trough goes by it misses Karl and we’re left with wondering what happens next. Seems like we’ve done this before once or twice, eh? So for now, we shall watch and just keep track of it with no issues for land areas seen anytime soon.

Meanwhile the weakening low pressure area that was once TS Julia continues off the Carolina coast. I see no reason to be concerned with this making any dramatic comeback but it’s out there, sheared to bits, but something to at least keep an eye on this weekend.

The only other area of interest is a tropical wave coming off of Africa now. It too could develop in the deep tropics as it moves generally westward. Interests in the Cape Verde Islands should be prepared for passing squalls and gusty winds as the tropical wave energy passes by this weekend.

I’ll have a video discussion posted here and to our YouTube channel as well as our app by later this afternoon.

M. Sudduth 9AM ET Sept 17

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Tropical wave in cental Atlantic a sign of what’s ahead

Tropical Weather Outlook map from the NHC showing area of interest in the central Atlantic

Tropical Weather Outlook map from the NHC showing area of interest in the central Atlantic

Not much going on in the tropics since Arthur earlier this month. This is typical for July which is usually a very quiet month in the Atlantic Basin.

In fact, we did not have any tropical waves to flare up worth mentioning until yesterday when the NHC issued an outlook for one in the central Atlantic. It rolled off of Africa a few days ago and has a low pressure area associated with it at the surface. Water temps are warm and overall, environmental conditions are generally favorable for development right now. However, this is likely only temporary as it looks as though conditions will not be so great for development as the week wears on. It’s just too early in the season yet for robust Cape Verde tropical waves to get going this far east. We’re still looking at another month or so before that happens.

The presence of this system does remind us of what could lie ahead. As I mentioned, July is usually not very active, especially in the deep tropics. Once we get in to mid to late August, conditions change and we begin to see more and more active tropical waves moving west from Africa. At that point, it will come down to upper level winds and, perhaps more importantly, instability in the atmosphere. If the mid-levels of the atmosphere are too dry with lower humidity value than usual, then the tropical waves will struggle to develop deep convection and will remain weak. On the other hand, if moisture levels are where they should be or are above average, then we would likely see a very busy August and September.

I believe that much will depend on the situation with the El Nino which was forecast to be coming on quite strong by August. As it turns out, there is barely any El Nino to talk about, especially in the central regions of the tropical Pacific. It just never made it and what warming there was has all but vanished. However, the water just west of South America, extending westward for several hundred miles, is still quite warm compared to normal. This could have just enough negative influence on the Atlantic side to help keep the peak months of August-October quieter than normal.

One thing I will be watching for is how much, if any, cooling takes place in this region of the Pacific. There are indications that we could see a considerable drop off in the surface temperatures of this area and if this happens, I suppose it could remove at least a portion of the negative influence for the Atlantic Basin. It’s just so complicated and hard to tell if one puzzle piece really makes that big of a difference considering how the other pieces fit together and interact with each other.

For me, the tropical wave that the NHC is talking about this morning is a sign that we are approaching the peak months of August-October. Thus it is a good time to remind you to be aware and prepared. Arthur was an interesting event in that it was so early in the season and it did not fall apart at landfall – instead, it continued to strengthen despite its close proximity to the North Carolina coast. If that is the way things will go this season, it won’t matter much if tropical waves develop far out in the Atlantic. What matters are the ones that would do so close to land, leaving little time to react. We’ll see how things shape up over the coming weeks but August is just around the corner and from there on, at least from a climatological perspective, the season should become more active. Time will tell just how active, that is the only certainty at this point.

I’ll have another blog post here tomorrow morning.

M. Sudduth 10:24 AM ET July 21

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July likely to end without much to talk about

East Atlantic tropical wave with low chance of development

East Atlantic tropical wave with low chance of development

Even though the NHC does have an area outlined in yellow today off the coast of Africa, I think that July will finish up without much to really be concerned about.

There is a formidable tropical wave located just off the African coast today and the GFS model in particular has been suggesting that this would develop. However, conditions in the tropical Atlantic are marginal at best with plenty of mid-level dry air present and a distinct lack of upward motion. As such, I think that this tropical wave will have a tough time developing much in the coming days. It is still July and climatology is a big part of the equation. There is a reason why we do not see much development in the tropical Atlantic this time of year – give it a couple of more weeks and things will change.

In the east Pacific, the NHC is monitoring invest area 98-E for slow development over the next several days. In this case, conditions are fairly favorable but what ever comes of it will move away from Mexico and not pose any threat for folks there.

In other news, our app, Hurricane Impact, is almost ready for Android devices. I am going to be testing it myself later today and will have a good idea of when we can expect it to hit the Google Play store. The app will feature the same features as our iOS version: daily video blog, HurricaneTrack.com blog, live Surge Cam, live weather data feed, field mission video blogs, our own tracking maps along with Twitter and Facebook integrated in to the app. It will also feature content from Mike Watkins of Hurricane Analytics which will be a new addition to our iOS version as well in the coming weeks. We are excited to have both platforms covered and know that the Android users out there will be equally excited. As soon as I know the release date, I’ll post a special blog with the announcement.

Enjoy the quiet pattern while it lasts. August is approaching and a month from now, I would venture to guess that we’ll have a lot to talk about.

M. Sudduth

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