Area of Interest in Caribbean & Damaging Wind Possible Today

September 28, 2020

The NHC has identified an area of interest in the northwestern Caribbean where they expect a weak low pressure system to form this week and they give this a 30% chance of tropical development over 5 days. This is what I mentioned yesterday, although I wasn't sure if or when we'd see something official about it. I didn't expect this quite as soon, it actually showed up on the 8 p.m. EDT outlook last night.

Since I'm sending an email this morning, there is a marginal chance of severe weather today extending through eastern Tennessee and most of Alabama associated with a damaging wind risk as the front moves through.

Stay safe and have a good week.

Chris

Deep South Weather Update - Sunday September 27, 2020

September 27, 2020

My weather updates will be mixed now as we transition into fall weather and with hurricane season ongoing. Starting with the tropics, there's not much going on. I thought we'd start to see some activity early this week, but it looks like what I was seeing was due to a model bias in the 11-15 day time frame. Around the weekend the combination of a few old cold fronts hanging around in the northwest Caribbean and a tropical wave pushing west may lead to development. There's no strong consensus, but there's enough of a signal in the models that it's something to watch. This'll be the general pattern we need to watch for in the tropics the rest of the year.

Up here in the mid-latitudes, two fronts will move through this week with the first arriving Monday afternoon through Monday night. We should all get rain from this followed by some cool air, 3-day rain totals are below (which includes this mess we have near the coast this morning). Starting Tuesday night lows will be in the 50s and highs in the 70s from Birmingham south, higher near the coast of course. Parts north of Birmingham into Tennessee will dip down into the 40's with highs in the 60s. The second front will push through later in the week. It looks to be mostly rain free but it will help reinforce the cooler air through the weekend. After the first front early in the week we may be mostly rain free for at least 7 days.

That's it for today. I'll let you know how the tropics look again later in the week.

Have a good week.

Chris

Marginal Chance of Severe Weather from Birmingham South to the Coast Tomorrow

September 23, 2020

This snuck up on me... The remnants of Beta will bring with it a chance of severe weather as it moves east tomorrow. For Thursday the Storm Prediction Center has issued a marginal risk for severe weather for Alabama from Birmingham south and for the Florida Panhandle. This coincides with a 2% tornado risk and 5% damaging wind risk. It'll be rainy/stormy on and off throughout the day but I think the greatest severe risk will be from noon to mid-evening, maybe lingering until morning in the east closer to the coast. The animation isn't a forecast, just a general idea how things may evolve.

Pay attention to any watches or warnings that may be issued throughout the day and keep an eye out for changing weather.

Have a good end of the week and a great weekend.

Chris

Monday Morning Update on the Tropics

 September 21, 2020

I hope you all had a good weekend and have enjoyed the cooler weather. Tropical Storm Beta will continue to bring rain and wind to the Texas and Louisiana coasts over the next few days. As you can see looking at the forecast cone we will need to watch for the possibility of a track that could bring the storm back over the northern Gulf. Even if that were to happen I think wind shear may be a bit too strong to support redevelopment. As it stands this morning there isn't much model support for this idea but it's something to watch.

The rest of the tropics are starting to quiet down a little compared to the last few weeks. We're about at the end of the African Easterly Wave part of the season, so we're probably not going to see many more systems that we have to watch from way out in the Atlantic. Instead we're transitioning to the part of the season where the Caribbean and Gulf become the hot spots for development. There will still be tropical waves but we'll be watching for them to develop as they get into the Carribean and we'll also have to watch for development after fronts pass through.

The NHC is watching an area between south Florida and the Bahamas that could develop later this week. This area of storms associated with a weak front will drift to the south-southwest for a few days and then come back north around Thursday. The NHC has given this system a 20% chance of development as conditions may become favorable as it comes north. Models don't do much with this system but it could be that they're just not seeing it well. It's nothing to be concerned about yet, just know it's there. 

In the longer term we may need to watch a wave moving into the southeastern Caribbean mid next week and we'll also have one fairly strong front push through around the same time.   

That's all for today. Maybe things will be quiet for a little while once Beta moves on.

Have a great week.

Chris

Friday Morning Tropical Weather Update

September 18, 2020

Taking a quick look at the tropics this morning there's still a lot going on. 

Hurricane Teddy may be a threat to the northeast US or Canadian Maritimes Tuesday or Wednesday or it may go out to sea. The bigger concern for most of us is TD 22 in the southwestern Gulf. The forecast for TD 22 is a mess. The steering influences are not very strong or certain so that makes for a difficult forecast beyond this weekend. It won't meander around forever, eventually something will pick up and move it along and we could see it moving to the northeast later next week. Right now eastern Texas and Louisiana are the places I'd be watching but that far out anything is on the table. Intensity forecast beyond the weekend is also a crapshoot so we'll just have to watch. If you want to see some models for 22, go here: https://www.weathernerds.org/tc_guidance/storm.html?tcid=AL22. Just note that this link will break if the storm gets named.

In other news, if you like cooler weather you're in for a treat. Starting this weekend areas near the coast will see highs in the 70's, maybe a day pushing toward 80, and lows in the lower 60's through mid week. Montgomery, Birmingham, and Hunstville will see lows in the mid to upper 50's and highs in the 70's, although Hunstville may stay a little warmer than places to the south with highs approaching 80. The Chattanooga area will see some even cooler temps with a few nights in the upper 40's. Things will warm up towards the end of the week but maybe we'll see cooler weather return the last week of September.

That's it for today. Have a great Friday and a great weekend. We'll know more about TD 22 around the start of the week.

Chris

Wednesday Morning Update on the Tropics

September 16, 2020

I just wanted to send a quick update about the orange area in the southwestern Gulf which has been designated Invest 90L by the NHC. Currently this system is expected to stay down near where it is. It may move north a bit and may eventually become a threat to southern Texas but it is not a threat to the north central Gulf or parts east. If it does develop eventually it is expected to push west. Teddy and the other stuff out there are also not a threat to the US at this time.

If you didn't know, Sally unexpectedly intensified to a 105 mph storm right before landfall last night. Some slight intensification was thought possible, but not that much. It still has 80 mph sustained winds at this time but it should weaken quickly as it moves to the northeast,

Chris

Tuesday Morning Update on Sally

September 15, 2020

Some good news this morning, Hurricane Sally decreased in strength a bit overnight and now has 85 mph winds, down from 100 mph. Sally does have a ragged eye now but it wasn't able to completely close off the eye enough overnight to allow for strengthening. Sally is now being impacted by wind shear and upwelling has even started to cool the water beneath the storm by a few degrees. Sally is not forecast to strengthen and may actually start to weaken before landfall although a few models support slight strengthening. The forecast with the 10 a.m. advisory is for Sally to make landfall tomorrow morning as an 80-85 mph storm near the mouth of Mobile Bay. The NHC shifted the early part of the track a bit more to the east but kept the later part the same. The NHC is favoring the GFS and ECMWF tracks which they deem the most reliable right now. There are still quite a few models showing a track more to the east so we'll see if there are a few more slight shifts before landfall.

Even though it is weakening Sally is still a dangerous storm. The NHC has called the potential for flooding 'historic.' with storm surge and inland flooding from rain being huge concerns.

The Florida Panhandle and Alabama coast are currently under a tornado watch and I expect the threat to continue through tomorrow. Several rotating storms have been noted by radar offshore but so far I haven't seen anything come ashore.

This may be my only update for today unless there are significant changes in the track or intensity. You all know what to do in this kind of weather so stay safe.

Chris

Monday Night Update on Sally

September 14, 2020

The 10 p.m. advisory for Hurricane Sally was just issued by the NHC. Sally thankfully hasn't strengthened since earlier and has probably weakened a little. The forecast has shifted east again, now showing a landfall Wednesday morning just west of Mobile Bay as a 110 mph storm. Sally is crawling along now at about 3 mph and is expected to gradually turn more to the north and then to the northeast. The eastern edge of the cone is now all the way over towards Fort Walton Beach, although the hurricane warning area has not been extended in that direction. It also still goes nearly as far west as the LA/MS border...

Here's the NHC's words regarding the track: 

"Weak high pressure ridging to the north and east of Sally is expected to cause the hurricane to continue to move slowly west-northwestward to northwestward for another 12 hours, bringing the center of the storm very near the northern Gulf coast. By Tuesday afternoon, when the hurricane will likely be just offshore, the models show the steering currents collapsing and Sally is likely to drift northward before finally turning northeastward ahead of a developing mid-level trough over the central U.S. by late Wednesday. There continues to be a significant amount of uncertainty on exactly where and when Sally turns northward and makes landfall, with model solutions ranging from a landfall on the Florida panhandle to a landfall in extreme southeastern Louisiana. It should be emphasized that it is always challenging to forecast the track of hurricanes in weak steering currents, and in Sally's case the weak steering is occurring very near land."

There's some meteorologist talk in there, but I think you can see just how much uncertainty we're still dealing with.

Sally still hasn't completely closed off an eye, and that has kept it from intensifying more. If it is able to close off all the way around we should see it strengthen some more. Hurricanes generally strengthen more after dark, so we could see that happen overnight. It may be trying to do so as I'm writing this based on what satellite and radar are showing. A run at category 3 strength is still possible, but I don't think we'll see too much more than that based on the intensity guidance. Another thing to note about the intensity is that if Sally sits in one place long enough, maybe longer than 24 hours, it will actually start to cool the water to where it can't intensify any more, it pulls out all the usable heat. Wind shear will also be increasing over the next day so that will help provide a more unfavorable environment as well. 

I think if we do see a track towards the far eastern side of the cone, it's likely to be one that is very slow at first and probably right along the coast after having used up a lot of the heat. There's also not as much heat available in the shallow coastal waters and that combined with some land interaction could weaken the storm on an extreme eastern track. So even though places as far east as Destin are starting to look like they're at risk, I don't think we'll see the storm make a beeline for that part of the coast over open water while maintaining or increasing strength. It's not impossible but I don't think it is likely. For places between Gulf Shore and West Pensacola I think the risk of this is a lot higher. Regardless of my thoughts things have been changing every so many hours so don't let your guard down if you're near Sally's path.

Along with wind, storm surge and flooding rainfall are going to be major issues for some areas, so please make preparations for these hazards.

To add to this the risk for tornadoes tomorrow has increased a little, with the SPC now showing a 5% risk area along the coast in the yellow area below. Keep an eye out for the rain bands as they come ashore and have a way to receive alerts.

I'll be keeping an eye on things overnight, the next full advisory is at 4 a.m. I may send out an update then or wait until the 10 a.m. advisory.

Have a good evening.

Chris

Monday Night Tropical Tidbits Youtube Video

If you get a chance, watch the video from Levi Cowan of www.tropicaltidbits.com, the link is below. He is a PhD meteorologist from FSU and his explanations for tropical weather are second to none. In this video he explains very well the uncertainty in the forecast and what may lie ahead for the next few days. It'll only take 14 minutes of your time.

Chris

https://youtu.be/5daY0lh8XRw 

4 p.m. Update on Sally - Now a 100 mph Category 2 Storm

September 14, 2020

As of the 4 p.m. update Sally is now a 100 mph category 2 hurricane. It is now forecast to make landfall as a 110 mph storm just west of the AL/MS border right around midnight Tuesday night. The NHC notes that additional eastward adjustments may be needed as they are favoring the GFS forecast which is more to the west than most other models. Here's a statement from the NHC regarding the track: "The specific timing and location of the turn will be critical as to the eventual location and timing of landfall along the north-central Gulf Coast." I still think we won't know where it's going to make landfall until maybe 12 hours out. The hurricane warning has been extended east to Navarre, FL with this advisory. Sally is expected to continue to intensify but there will be some factors that will slow the intensification process. I think we might see a storm stronger than 110 mph, but hopefully not too much stronger than a low end cat 3.

With Sally intensifying quicker than any model had predicted, it may take until tomorrow morning around the time of the 10 a.m. update before the models catch up to what the storm is doing. There is still a lot of spread from model to model and from run to run. Hopefully this consolidates some overnight and we see some trends where the models start to match what is actually happening. The HWRF has been close, but even it is playing catch up.

I'll send out another update in the morning. Have a good evening.

Chris

Sally Now A Strong Hurricane With 90 mph Winds!

September 14, 2020

Sally went from a 65 mph storm at 10 a.m. to a 90 mph storm at 11 a.m.! It also dropped 5 mbar in pressure. The NHC just issued a special advisory and Sally is now forecast to be a 105 mph storm at landfall. It'll be interesting to see what changes we see for future forecasts and model runs now that Sally has strengthened so fast.

Chris

Monday Morning Update on Sally

September 14, 2020

I think I got the day right this time...I again wanted to wait until the full advisory at 10 a.m. to send an update because the track has been shifting a little with each forecast. Sally is still trying to organize this morning, with the storm center bouncing around a bit as it tries to align itself from the surface up through the atmosphere. Sally is still a 65 mph storm and is forecast to become a hurricane later today on it's way to making landfall as a 90 mph storm on the Mississippi coast. The center of Sally has reformed to the east of its previous location and the track guidance is over to the east some more, so the official track and cone have shifted to the east again. This is what I was concerned about late last night, but at least the shift east has only been subtle since then and the intensity forecast is still the same. We shouldn't see any major changes but I'm afraid that we might not really know that landfall point until 12 hours or so before it happens, although we should be able to narrow it down as we get closer. People in the extreme western Panhandle are going to have to watch Sally all the way in just in case it keeps coming east. I still think a storm of category 2 strength is possible, but that looks a little less likely this morning.

The SPC has placed the Florida Panhandle and parts of the surrounding area in a marginal risk area for severe weather over the next three days due to a slight chance of tornadoes associated with Sally. These areas will probably shift around a bit so stay aware of any watches that may be issued for your area. I probably won't make an update again on this unless the risk increases.

That's it for now, we'll keep watching to see what might change.

Have a good Monday and a good week.

Chris

CORRECTION : Sunday Night Update for TS Sally

You all know what day it is, the subject of my previous email said Monday, I'm getting ahead of myself. Sorry about that.

September 13, 2020

Sally is starting to organize a lot more tonight and I think we're seeing the beginning of the intensification phase that's been expected. With the 10 p.m. update, the NHC has shifted Sally's track back to the east a little and slowed the storm down. While the track center hasn't moved a whole lot, the cone has come quite a bit to the east due to the change in the turn location. The NHC has the storm making landfall right after daybreak Tuesday raking the Mississippi Delta as a 90 mph storm. In their discussion the NHC states that their forecast is to the west of most of the guidance so it may be adjusted to the east even more overnight. Earlier today I was feeling pretty confident that the Florida Panhandle was looking pretty safe but I'm not as confident tonight. I'm not trying to get anyone too excited, I just want to keep you informed about the different possibilities. Most of you are in the Panama City area and I think you all are fine for now, but people a bit more to the west need to stay alert.

Both of these trends, to the east and slowing down, are concerning because it gives the storm more time over water if it misses the Delta to the east which would allow for more intensification and increases the track uncertainty if it stalls over water. If we're getting back to the scenario where it could stall over water that allows more time for the steering environment to change which could ultimately bring a stronger storm more to the east. Also concerning is the 18Z HWRF run, after showing the storm being barely a hurricane for the 6Z and 12Z runs, it is back showing nearly a category 3 storm making landfall in Mississippi. Other intensity models continue to support a category 2 storm but about half show category 1 intensity. Something people in the extreme western Florida Panhandle need to watch for is if the storm stalls just off the Mississippi Delta tomorrow night it might start curving to the east as it heads north again Tuesday night into Wednesday, putting the Pensacola area or even points a little east at greater risk. I think this is an outlier scenario at this point, but it is a possibility. This area is back in the cone now and the cone only covers two-thirds of historical forecast errors. We'll see what the overnight trend is and if the NHC brings the track more to the east.

I also want to mention that the SPC is now indicating a marginal chance for severe weather tomorrow, coinciding with a 2% tornado risk, from just west of the Florida Big Bend through southeast Louisiana. People right along the coast should stay aware of the weather as rain bands come ashore.

Let's see what tomorrow brings. 

Have a good evening.

Chris

Sunday Morning Update on TS Sally

September 13, 2020

I wanted to wait until the full advisory from the NHC at 10 a.m. to send out an update this morning. Sally is starting to organize but it still doesn't have convection wrapped around the center very well. Still it has 60 mph winds which isn't too far from hurricane strength. It should continue to organize and strengthen and it is expected to be a hurricane sometime tomorrow. As many of you with a weather radio or weather alerts on your phone will know, hurricane and tropical storm warnings were issued with the 4 a.m. advisory. The forecast intensity has been steadily increasing and it is now for a 90 mph storm at landfall, with the NHC noting that it may actually be a little stronger. The track has been nudged to the west a bit and now shows a southeast Louisiana landfall just after midnight on Tuesday. The forecast has the storm coming in faster now which is good because we may not see a stall over water which would bring hazardous conditions longer and add to the track uncertainty. 

Tornadoes are still a possibility but the Storm Prediction Center has yet to issue any probabilities or designate any severe weather threat areas. While no specific risk has been identified, there could be an area favorable for tornadoes along the Florida Panhandle later today into the overnight hours and we may see the outlook upgraded at some point. Right now, the SPC doesn't see much of a tornado risk tomorrow and overnight into Tuesday. Beyond Tuesday morning there may be a possibility for tornadoes but due to uncertainty in what the environment will be like no specific threat has been identified.

The latest run of the HWRF has cooled a bit on it's forecast, for the last several runs it had been showing a category 3 storm at landfall but as of the 6Z run, which ran a little after midnight, it only shows a category 1 storm. Several of the intensity models still support a category 2 storm as shown below so we'll see if this latest HWRF run is a fluke or the start of a new trend. I'm a little skeptical of this latest run but there may be good reasons for the sudden decrease in intensity, we'll see what the 12Z run shows. The Euro and GFS operational models still don't even show it becoming a hurricane, but I think they're too weak on their forecast.

The track forecast is getting more certain. It is helpful that a stall over the water looks a lot less likely, so that has tightened things up a bit regarding the possible landfall points. There is still quite a bit of spread where the storm may go beyond midday Tuesday, and that could determine where a lot of the rainfall ends up.

That's it for this morning. I think most of the Florida Panhandle can breathe easier now. LA, MS, and AL will likely be dealing with a fairly hazardous storm in a day or so. Have a great Sunday, I'll send out another update late today or tomorrow morning.

Chris

Saturday Morning Update on TD 19

 September 12, 2020

TD 19 is now over land in South Florida and will enter the eastern Gulf later today or tonight. It was very close to tropical storm strength at landfall but has since weakened. It currently has a lopsided structure with most of the convection (storminess) to the southeast over the Florida Straits. It'll be interesting to see if the low level center tries to reform down in this direction. If it does that could change the forecast a bit.

The official forecast from the NHC isn't much different than it was yesterday. They're still forecasting a strong tropical storm to make landfall near the MS/LA border Tuesday or early Wednesday. This is weaker than the intensity model consensus and the NHC has again stated that a hurricane or stronger is possible at landfall. There is some wind shear that could inhibit development so the NHC is keeping their forecast conservative as there's some uncertainty regarding how much this may limit the intensity. The track forecast is still a bit uncertain after two days. One worrisome trend is that the storm is expected for move slowly which could allow more time for strengthening and drop a lot of rain as it nears the coast. Isolated tornadoes are also possible Sunday into Monday across north Florida.

Model guidance is a little more concerning this morning. The HWRF shows a category 3 storm making landfall along the Mississippi coast Tuesday morning. This model can overdo intensity at times so keep that in mind, but sometimes it is right. It forecast Laura's intensity pretty well. I'm not skilled enough yet to know when it is acting up but what it shows is concerning. The GFS brings a category 1 storm into almost the same location but it has the storm grazing extreme southeast Louisiana before hooking north and hitting Mississippi. The Euro brings the storm in a little faster and a hair more to the west as a tropical storm. Yesterday I said the Euro had this as a hurricane, that was a mistake, it had a tropical storm similar to what we see this morning. Either way, I now think the Euro is probably too low on its intensity forecast. There are various other model solution but I think you get the idea. I think it's more likely than not that TD 19 will become a hurricane by late Sunday or early Monday in the northeastern Gulf. I don't have much to say about the track guidance as I think the NHC's cone captures that fairly well. I made a statement yesterday that implied that a stronger storm would be more likely to go west, that is incorrect the way I stated it. In a general sense the longer the storm is over water, the more west it will go. However, a stronger storm will feel a different steering influence than a weaker storm and will turn to the north earlier. So given a certain steering influence, a stronger storm is likely to go more the east and a weaker storm more to the west. Levi Cowan covered this well in his video last night.

Taking a brief look at the rest of the tropics, there remains quite a bit of other activity. Paulette looks to threaten Bermuda as a hurricane in a few days. The red 'x' is still out there moving west, now Invest 95L. Models have cooled somewhat on developing this and a track to sea now looks more likely but not certain. The Lesser Antilles could still see some impacts but I think the US might be out of danger. Another wave that will come off of Africa Monday (not shown) may be the next one to watch.

I'll send out another update on TD 19 later today or tomorrow morning. It's a good time to think about your hurricane plans and get some supplies if you need some. No need to get too excited, but it's good to be prepared. Have a good Saturday.

Chris

TD 19 Forms East of Florida

September 11, 2020

The NHC has started issuing advisories on TD 19 (previously Invest 96L) located east of South Florida, the forecast cone is shown below. TD 19 is only 5 knots away from being a tropical storm so it's likely we could see it get named before it makes landfall near Miami overnight. After that, the storm will cross the Peninsula and enter the eastern Gulf on Saturday. Once over open water it is expected to steadily intensify. The official intensity forecast stops just short of hurricane strength but the NHC cautions that their forecast is conservative and could likely be increased. Regarding the track, the NHC states that there is considerable uncertainty beyond 48 hours and that areas well outside the cone should remain aware.

Computer models are now showing more development than they were this morning. The hurricane specific HWRF, which started to run when this became 96L, shows a strong category 1 hurricane skirting the coast near Pensacola with the storm making landfall near the western end of Dauphin Island, AL early Tuesday. The Euro shows a similar solution but brings the storm in close to the coast off of Panama City and then keeps the storm just off the coast with it making landfall near the MS/LA border late Tuesday as a category 1 hurricane. The GFS takes a weak tropical storm into southeast Louisiana Tuesday morning. Several of the intensity models have solutions showing the storm making it to hurricane strength. Based on all of this I think it is more likely than not that TD 19 will become a hurricane, maybe as early as Sunday night if not by Monday. Fortunately I don't think it will have enough time over open water to strengthen much beyond a category 1 storm. The track guidance seems to be consolidating around a landfall somewhere to the west of the Florida Panhandle, but as mentioned above there is a lot of uncertainty with this right now.

A couple of points of caution. One is that models are just now getting a good look at this so we may see some changes as they start seeing the storm better. We should get some hurricane hunter flights and that will help feed the models with better data. Also, the more time this spends over water the stronger it may become, there's really not much to inhibit its strength. That being said more time over water probably means a track farther west as well.

That's all for today, I'll send out another update in the morning.

Chris

System East of Florida is Now Invest 96L

September 11, 2020

I'm only going to talk about the orange system east of Florida this morning, now designated Invest 96L. The National Hurricane Center has increased chances of development to 40% over the next two days and 60% over 5 days, here is part of their statement:

This system is forecast to move westward at about 10 mph, crossing the 
Bahamas and Florida today and tonight and moving into the eastern 
Gulf of Mexico on Saturday.  Upper-level winds are expected to 
become conducive for development, and a tropical depression could 
form while this system moves slowly west-northwestward over the 
eastern Gulf of Mexico this weekend and early next week.

Levi Cowan explained a lot about this system in his video update last night. Computer models still aren't showing much development from it but he said sometimes models can miss systems like this. Now that it is an invest, the hurricane models such as the HWRF and HMON will start looking at it so we'll see what they come up with. The NHC mentions that a tropical depression could form and I think the most we could expect from 96L would be a tropical storm. Interestingly, the Tallahassee NWS office, which covers the Florida Panhandle east through Walton County, only mentions this system due to the increased rain chances it'll bring to the area. They really don't seem too concerned about tropical development from it.

Have a good Friday and a great weekend. I'll keep you posted on how 96L evolves as well as the rest of the tropics.

Chris 

I want to make a correction to yesterday's (9/10/2020) post. Where I said "although the eastern most system will encounter some wind shear.." I meant to say "western." Sorry about that.

Quick Morning Update on the Tropics

September 10, 2020

Today marks the climatological peak of the Atlantic hurricane season (yay...) and the 5-day outlook doesn't disappoint in this regard. I wanted to provide a quick update (ok, maybe not so quick now that I've written it...), mainly due to the potential for short term development in the Gulf. Two surface low pressure systems, one northeast of the Bahamas and one in the northeastern Gulf, are being watched by the NHC and have been given a 30% and 20% chance of development respectively. Conditions in the Gulf will be favorable for development, although the eastern western (edit: 9/11/2020) most system will encounter some wind shear, but there is very little organization with both systems and they won't have a lot of time over water before they move over land this weekend or early next week. Other than a few hints from a couple of ensemble members models aren't bullish on these. I just don't think they'll have time to really spin up and get going. I think the system near the Bahamas is the one to watch more closely as it looks a little healthier and will have the best conditions, so it's possible we see this develop into a tropical storm in the Atlantic or northeastern Gulf. Right now I'm not too concerned about either but anytime we see low pressure systems starting to form in an area with favorable conditions they need to be watched.

There's nothing new to say about Paulette and Rene. Again it's still possible Paulette tries to sneak in towards the East Coast but I think that's unlikely. Rene is what is fondly called a "fish storm" by some, it's expected to curve out to sea and only bother the fishes :).

I'm getting a little more concerned about the wave coming off of Africa. It is the red 'x' and long red oval in the eastern Atlantic. There are stronger indications that this system may not curve out to sea as it heads west. The GFS, ECMWF (Euro), and Canadian operational models bring a storm into the northern Lesser Antilles and then northeastern Caribbean mid next week. The GFS and Euro ensemble members are somewhat split on this so a track more to the north and out to sea is still a potential solution, although I think a track to the west is slightly favored. We're well beyond the 3-5 day range that I like to stay within for forecasting but I want to let you know how models have been trending. I think it's virtually certain we'll see this wave develop, we just need to watch where it goes after that. I think we'll have a better idea this weekend or early next week.

The orange oval is yet another wave that will enter the Atlantic this weekend, something else to watch...

Have a great rest of the week. I'll send out another update as the picture evolves.

Chris

Tropical Weather Update - September 8, 2020

September 8, 2020

The tropics continue to be active but there are currently no significant threats to the US. Out of that "fruit salad" we had a few days ago, as some like to call it, Paulette and Rene have formed. You can find the forecast cones for both on the NHC website. Paulette has a chance to sneak in towards the East Coast but it looks like it will probably curve out to sea. Rene is not considered a threat at this time and will most likely curve out to sea. The orange area off the Carolinas, now Invest 94L, bears some watching but is not expected to significantly develop.

The red area way out east is a strong tropical wave that will enter the Atlantic on Thursday. This we really need to start watching around the end of the week, but it'll be a week and a half or better before we would get concerned about it. The models have pretty excited about developing it. The GFS, Euro, and others, along with many of their ensembles, show it developing as it moves west. You can see TC genesis probabilities for it below (ignore the other areas). What is concerning is that a track out to sea is maybe less likely for this system, but this is far from certain at this point in the forecast. We could definitely see a storm threatening the northern Lesser Antilles towards mid next week.

We're getting to the time of year where we're going to start getting a regular cycle of cold fronts moving east and we might actually see some cooler weather from one in a few weeks. What these fronts will do occasionally, depending on timing and location, is break down the high pressure over the Atlantic that wants to steer storms to the US. This could allow any storms to recurve to sea away from the US. We're starting to see that now with Paulette and Rene. These fronts can also help pull storms up from the south if they're way down in the Caribbean or spin up tropical cyclones in the Gulf or off the East Coast if they leave some energy behind, they can be a double edged sword.
This season continues to set records, Paulette and Rene are the earliest "P" and "R" storms. We only have four more letters and then we start using the Greek alphabet! Thankfully, even though we've had an above average number of storms, overall they haven't been very strong. Below is a plot of Accumulated Cyclone Energy (ACE) for the season from Colorado State's site and as you can see we're actually a hair behind where an average season would be.

That's all I have for today. I'll have another update around the end of the week once we know more about what this next wave is going to do.

Have a great week.

Chris

Tropical Weather Update - September 4, 2020

September 4, 2020

The 5-day outlook continues to look busy in the eastern Atlantic.There are a few healthy waves that need to be watched, the orange and red "x's" (the orange 'x' is Invest 91L), and then another wave that will enter the Atlantic on Sunday, the eastern orange area. I think we will see development in this region early next week but there is a lot of uncertainty on timing and location. The good news is that there are no serious threats to the US soon, although the Lesser Antiles may see something mid to late next week. Also, not shown is a wave in the western Caribbean that forecasters have been watching, but doesn't show any strong signs of development, for now just know it's there.

The forecast has two major issues that are driving a lot of uncertainty. One is that those three orange and red areas along with a few other waves are expected to interact. Where, when, and how that occurs is mostly unknown so until it plays out we won't have a good idea of where a storm, or multiple storms, may form. We're probably looking at the Monday/Tuesday time frame before this settles and we start to see serious development. What the models seem to agree on is that the red 'x' will pinwheel around the leading orange 'x' and become the leading system (leading as in more western, not necessarily stronger). After that, models disagree on where the dominant development will occur. The Euro develops the red 'x' once it becomes the lead system and then a wave coming off of Africa next Thursday. The GFS doesn't do much with the first two and instead develops the trailing orange area that enters the Atlantic Sunday. The European ensemble isn't too crazy about any of these and instead tries to develop a wave coming off of Africa next Thursday. The GFS ensemble tries to develop the red 'x' once it is in the lead and then also the trailing orange area. This is neat to see in the models, so I've shown the Euro and GFS below, but I'm telling you all this to highlight the uncertainty. We know something is going to happen, just not where or when.

The other forecast issue is regarding where these storms go if they do form. Right now, a track out to sea away from the US looks possible but there is debate whether the mid term forecast is correct. We've had a high pressure sitting in the western Atlantic that has steered a lot of the storms we've had to the west into the US. This is what happened with Laura. The models are showing a strong front (for this time of year) coming through and breaking down this high, allowing potential storms to escape to sea. The debate is that a lot of forecasters aren't really buying into the idea of this strong front. So if this doesn't occur then steering conditions could be such that potential storms stay on a more westward track, again threatening the US. It'll probably be later next week before we get a better feel for what will happen with this.

To sum things up the Atlantic is busy and we need to keep watching. I think we will see one or more storms develop in the next 5-10 days but it'll be early next week before we have a feel for where development will occur and maybe mid-week or later before we know if the US is at risk.

I don't mention it a lot, but all of these emails get posted to Twitter @DeepSouthWXUS and my blog: https://www.deepsouthwx.com/. There are also some weather maps on the blog and links to other resources. The models shown today are from Levi Cowan's great site: www.tropicaltidbits.com. He also does excellent video updates on YouTube when there are storms that we need to start watching here in the US.

Have a great Labor Day weekend. I'll send out another update early next week.

Chris