Joaquin forecast tricky, Ida coming back from the hurricane graveyard

Overnight model plot showing the fairly large spread in track possibilities for Joaquin

Overnight model plot showing the fairly large spread in track possibilities for Joaquin

This is going to be one of those times when nothing comes easy. If we are going to have hurricanes, might as well have them easy to forecast and sometimes, even when they are intense like Katrina, they are. Others, not so much. The case with Joaquin looks to be a real pain in the neck. Before getting to the forecast part, let’s take a look at what we know.

As of this morning, Joaquin was a 40 mph tropical storm battling relentless northerly shear. Remember, upper level winds are not favorable when the pass over a developing or established tropical cyclone. The best environment is one that features outflow channels and light winds at the upper levels, to allow very deep thunderstorms to tower high in to the atmosphere. Right now, this is not what is happening with Joaquin and unless the shear abates, the storm will struggle.

Water temps along the track of the storm are plenty warm with ample undisturbed upper ocean heat content. While it is not nearly as high-octane as the NW Caribbean, the western Atlantic has plenty of energy for a hurricane to develop from and feed off of. The question is, will Joaquin thrive or starve at the head of the buffet?

It really will come down to how much the shear relaxes, if at all, in the coming days. Some of the intensity models show significant strengthening, as does the global model ECMWF. Keep in mind, some models are developed specifically for tropical cyclones where as the global models predict weather on a global scale and the tropical cyclone is part of the overall big picture. Right now, the NHC is admittedly being conservative with the intensity forecast – holding below hurricane strength.

Now for the track forecast. This is obviously what everyone wants to know about. As I said in my opening paragraph, we wish it was always easy but it’s not and so we deal with it.

I want to point out that the NHC makes mention of the fact that their confidence in the track forecast is “extremely low” right now. I think this is incredibly honest and shows the human side of this tedious work. Model guidance is helpful but is spread out right now, or divergent, and thus the forecast of where Joaquin will track is very tough to call. Here’s why.

First, intensity will likely dictate track to some extent. A stronger, deeper hurricane situated in the atmosphere might, just might, be enough to get swept out to sea by an approaching trough of low pressure moving in to the Southeast later this week. On the other hand, no matter what the intensity of Joaquin is, it may get caught by the trough if it tries to cut itself off from the main flow- what we call a cutoff low. This could swing Joaquin northwest with time and bring it in to the Mid-Atlantic states later this weekend. Many of the model solutions show this happening to some extent. Of course, others do not. This is why the track forecast is so tough to call right now. What’s more frustrating is that we are not talking about a week to 10 days out like we see with large hurricanes coming in from the eastern Atlantic. Joaquin is literally in the backyard, waiting to make its move. You would think, and hope, that with it being so close to land already (relatively speaking of course) that the forecast would be easier. It’s just not and that’s the reality of the situation.

One thing we can count on is data. NOAA will have plenty of additional data to input in to the global models as soon as the G-IV missions begin for Joaquin. The high-altitude jet will drop numerous devices that will sample the atmosphere and give the models more data from the steering layer to work with. This should help to refine things in the days to come.

So what should you be doing now if you live along the coast from say, North Carolina to Maine? Just keep monitoring what’s going on and be ready to act if it looks like Joaquin will in fact head your way. Remember, even if it transitions from a hurricane ( assuming it becomes one) to a post-tropical storm or other less commonly used term, there will likely be a lot of rain, wind and more coastal issues. The beaches from parts of eastern Florida up the East Coast are not in their best shape right now due to recent nuisance storms and persistent onshore flow. Joaquin need not be a substantial hurricane to cause substantial problems for people and property. Do not lose sight of the fact that a storm of any magnitude can impact you. Needless to say, it will be a very interesting next few days.

As if Joaquin weren’t enough, we have to watch for the remnant energy from Ida to try and stage a comeback. The NHC gives it a 40% chance of doing so and there is a chance that this system too gets involved with the pattern near the East Coast in the coming days. The result is likely to be a tremendous amount of rain and serious beach erosion from the North Carolina Outer Banks to New England.

I will post a full-featured video update this afternoon highlighting the very latest on Joaquin and what the chances are of Ida making a comeback. Stay tuned, it looks like October is going to start off very stormy – how much so and what impact it all has remains to be seen.

M. Sudduth 8:40 AM ET Sept 29

All kinds of things going on in the tropics this week – just no hurricanes

Wide satellite shot showing all of the areas of interest in the Atlantic Basin this morning

Wide satellite shot showing all of the areas of interest in the Atlantic Basin this morning

Here we are at the end of September and not one hurricane has formed in the Atlantic – not this month anyway. The only two hurricanes were Danny and Fred and those were in late August. I do not see much potential for hurricane formation over the coming days but there is plenty to talk about in terms of other action in the tropics.

First up, we have invest area 99L in the Gulf of Mexico. The latest info from the NHC suggests that it won’t develop in to a tropical storm before reaching the coast tomorrow or Wednesday. Upper level winds are just too strong and continue to blow across the top of the system, not allowing deep convection to develop. However, there is ample tropical moisture associated with this system and very heavy rain is possible for a large swath of the eastern Gulf Coast states and areas inland from there.

The coasts of Mississippi and Alabama received excessive rain over the weekend with flooding issues becoming a big problem in some locations. More rain is on the way but it looks like the heaviest totals will be shifting further to the east towards Florida as the moisture plume moves northward out of the Gulf.

Meanwhile, we now have TD #11 which formed yesterday over the warm waters of the southwest Atlantic. The official forecast calls for no significant additional strengthening but it would not take much for this system to become a tropical storm. It should not impact land directly but the track is aimed towards the East Coast of the U.S. and this could have an influence on the weather this weekend. More on that in a moment.

Next there is the ghost of Ida. Although no mention was made on the NHC’s latest outlook, I think there is a fair chance that Ida makes a comeback as it continues to move off to the west with time. Again, water temps are plenty warm and the MJO (favorable upward motion) is turning more positive for development for the Atlantic Basin. This should allow Ida to grow and possibly become a tropical storm again later this week. It won’t affect land, not yet anyway but needs to be watched since the pattern is such that a lot of energy from the tropics is being aimed at the East Coast of the U.S. This brings me to the weekend….

Some of the model guidance is suggesting that a combination of energy coming in from the Gulf, meeting up with energy from TD11 could produce a coastal storm that would affect areas from the North Carolina Outer Banks to points north towards Cape Cod. It has been interesting to watch each run of the various models over past few days as some will show quite a bit of wind and rain while others do not or are not as pronounced with the effects. What does look like a certainty is that a lot of rain is headed for areas of the Southeast, Mid-Atlantic and eventually parts of New England as the week wears on. How strong any one system is remains to be seen. Will we have a singular intense coastal storm or a large, spread out mess? It’s tough to call right now but there is an awful lot of heat energy available from the tropics right now during a time of year when the atmosphere is changing from summer to fall. Stay tuned, looks like a wild week ahead!

In the Pacific, tropical storm Marty is lurking off the coast of Mexico with 70 mph winds. The forecast track bends Marty sharply west before reaching land but as always, heavy rain is a possibility as outer bands from the storm circulate inland over the next couple of days.

I will have a full video discussion posted later this afternoon covering all of the goings on in the tropics.

M. Sudduth 9:20 AM ET Sept 28

Ida hanging around, coastal mess for NC, SC, VA plus minor Gulf system to watch for

The tropics are quite a mess this morning. That’s the best way to describe the scene across the Atlantic Basin. Here is a run down of what’s going on out there…

First up, Ida. This storm just keeps hanging on and taking a beating from various weather features that pass by and lash out. Steering currents remain weak but eventually Ida is expected to turn northeast and head further out in to the open Atlantic. It remains to be seen how strong it will become, some models indicate significant strengthening while others barely anything at all. It matters little really since Ida won’t be affecting any land areas.

Next we have a complex weather situation off the coast of the Southeast U.S. which has almost nothing tropical associated with it except for the fact that it’s over very warm water.

Basically we have a coastal trough of low pressure, or an elongated area of low pressure as opposed to a focused surface low, hanging around just offshore of the Carolinas and Virginia. The coastal trough alone is not a big problem but when we factor in these enormous areas of high pressure moving by to the north, then things get interesting.

Wind is created by the difference between areas of high and low pressure. I think we can all understand that concept pretty well. The greater the difference between high and low pressure, the stronger the wind. We call this a gradient, like going down a steep hill versus a gradual slope. Now imagine the wind blowing over a fairly long stretch of water, we call this a fetch. The more distance the wind blows from a certain direction over the water, the higher the waves become. This is important in understanding the situation along portions of the Southeast and Mid-Atlantic states over the next few days.

Global models indicate that the coastal trough will remain in place for the next few days with possible ripples of weak low pressure developing along the trough, moving northeast with time. This, in combination with strong Canadian high pressure in the Northeast, will help to squeeze the pressure gradient to the point where large waves will likely result and batter parts of the coastline.

We have already seen this in areas such as the NC Outer Banks where beach erosion at the times of high tide has been an ongoing issue. I think that it will only get worse as we head in to the weekend.

In addition to the rough surf and high waves, the chance for areas of heavy rain to develop is also on the table. With very warm water in the western Atlantic, there is plenty of fuel for low pressure to tap in to and dump several inches of rain across inland areas. It’s impossible to know which locations will receive the highest rain amounts but overall, it looks like a wet and unsettled weekend for portions of the Southeast and Mid-Atlantic.

Last but not least, the Gulf. The NHC has outlined an area of interest in the southern Gulf of Mexico where a broad area of low pressure is expected to develop sometime next week. Normally this would be cause for concern but this season, the incredible amount of wind shear in the atmosphere should limit any development that does take place. None of the reliable model guidance suggests anything more than a strung-out, sheared low pressure area to form. This would limit the impact from wind and surge but the chance for very heavy rain exists and we will want to monitor this region carefully as we in to early next week.

That’s it for now – I will post a video blog update later this afternoon.

M. Sudduth 1:15 PM ET Sept 23

 

 

Ida going to be around for a while as we begin to watch Caribbean and Gulf

TS Ida tracking map from the NHC

TS Ida tracking map from the NHC

Ida has become stronger over the weekend with top winds of 50 mph as of this morning. The forecast keeps Ida on the maps for the next five days, eventually strengthening it in to a hurricane over the open Atlantic. Some of the long range models suggest that it could become quite a strong hurricane as the pattern changes and becomes more favorable for intensification. There are no indications that Ida will ever impact land, at least not directly. Perhaps, if it becomes strong, it could generate swells that would eventually impact the East Coast but that remains to be seen.

As we move through the week ahead, we will need to begin watching the western Caribbean and the Gulf of Mexico for possible development. Almost all of the global model guidance now suggests that something will form around the Yucatan peninsula and move in to the southern Gulf.

Climatology suggests that this is the area to watch as we begin to shift away from the Cape Verde storms (we have had several this season) and focus more on the western Atlantic and Caribbean Sea, Gulf of Mexico regions.

GFS day 6 map showing a broad area of low pressure in the western Caribbean Sea

GFS day 6 map showing a broad area of low pressure in the western Caribbean Sea

So far, the long range guidance seems to want to develop a low somewhere in the vicinity of the western Caribbean with a track towards the north to north-northwest. This would bring the system in to the Gulf of Mexico where water temps are still very warm. From an ocean heat content perspective, there is plenty of potential for development.

However, I am skeptical because the upper level winds look way too strong for anything purely tropical to get going. A large and expanding area of high pressure does seem to build in across the region but the low-shear environment appears to me to be to the south and east of where the low would be. None of this makes much difference right now since we have more than five days to monitor the situation. In any case, it is a region that becomes more favorable towards the end of September in most seasons. Whether or not that is the case this year remains to be seen. I’ll be watching the evolution of the pattern very closely over the next several days.

Satellite image showing deep thunderstorms moving across Mexico towards Arizona

Satellite image showing deep thunderstorms moving across Mexico towards Arizona

Meanwhile, another possible significant flood event is taking shape out in the Desert Southwest as moisture from a tropical depression is moving north from the Pacific and in to Mexico and Arizona. The region from southeast California stretching across all of southern Arizona and in to New Mexico is under the threat of flooding from excessive rainfall. Anyone with travel plans to the region needs to keep a very close eye on the situation and be ready to avoid any and all areas of flooded roadways, etc. This event has the potential for widespread flooding across several major population centers across the Southwest. The worst of the weather is likely to take place over night tonight and in to tomorrow, mainly across southern Arizona.

I’ll have a video blog posted later this afternoon with more details on all of the goings on in the tropics.

M. Sudduth 7:30 AM ET Sept 21