“Tropical” Storm #Odette, other disturbances

Here’s the morning surface analysis from TAFB (the Tropical Analysis and Forecast Branch, within the National Hurricane Center) over the GOES IR satellite image …

click to embiggen.

The two features of interest are “Tropical” storm Odette, and the disturbance approaching the Leeward Islands(lower right, above the word “Surface” in the label). I put Odette’s title in quotes because Odette isn’t really very tropical – and despite having some areas of tropical storm force winds, it’s really more like a nor’easter in structure and impact. It will be bringing wind and rain to the Canadian Maritime Provinces, especially Newfoundland (more properly, Vinland). To quote from the Environment Canada forecast

This storm is expected to behave more like a strong fall storm with northerly winds and heavy rain. A cold front moving over Newfoundland on Sunday will interact with Odette's moisture to enhance the rainfall over southeastern Newfoundland later in the day Sunday and Sunday night. A special weather statement is in effect for eastern Newfoundland for Sunday into Monday. There will be some minor influence in Nova Scotia's weather with gusty northerly winds on Sunday. Gusts could be near 70 km/h or so in Cape Breton which may cause some minor issues. Some enhanced rainfall is likely over eastern Nova Scotia Sunday morning as Odette interacts with the cold front.

Odette is another example of a storm that needs advisories, but doesn’t quite fit our current system of “tropical gets one kind of advisories, other storms get something different.” Why does this matter? It’s inconsistent for one thing, and confusing in that a 50 mph wind and coastal flooding from a nor’easter has a different warning structure and, especially in the commercial weather media world, different level of reporting and attention.

On the science side it can cause problems as well, especially in the popular mindset. As data has become better, and marginal storms are tracked and named, there is an impression that tropical cyclones/hurricanes are more frequent. It is true that storm characteristics seem to be changing (almost certainly due to human driven climate change), but you have to be careful with the numbers game because the metrics haven’t been consistent over time. Simple storm counts and trends aren’t diagnostic when it comes to climate change. That’s not a criticism of NOAA or the Hurricane Center – they are doing their job, which is to issue watches and warnings, and over time they have continued to get better and better at it. But people who use that data for other purposes need to be very careful. Which brings up the insurance world.

At least in the US, how something is named and warned has a direct impact on things like insurance deductibles, and the same damaged roof could cost a homeowner $500 or $5000 depending on how the contract handles the “named storm deductible.” After the huge industry losses in the late 1980’s and early 1990’s due to earthquakes and hurricanes, rather than design a rational system the insurance industry successfully lobbied state regulators to allow them to have separate “catastrophe deductibles” for these major events. So US consumers face a bewildering array of contract conditions depending on the hazard or if a storm is named or not. You get crazy things like if your roof is damaged and water leaks in and damages your carpet, it’s covered by private insurance. But if that same rain backs up because of a drainage problem, enters your house and ruins your carpet, it isn’t covered unless you have separate, Federally sponsored flood insurance from FEMA. Even outside the US things like reinsurance contracts and parametric insurance depend heavily not on the actual impacts or damage a storm produces, but how it is classified and if it is named or not. It’s a dumb system – insurance triggers should NOT be tied to a watch and warning system. That just isn’t what it was designed for. End of rant.

For the US, it looks like the impacts of Odette will be limited to high surf and rip currents; there are no watches or warnings at this time. As for the disturbance off of the Leeward Islands, it may briefly become a tropical system, but isn’t likely to last long once it starts its northward curve. As the Tropical Weather Outlook says, people there should “monitor” until it is safely past …

Where did it go? (Update for 16 Sept 2021)

To reinforce what was said (repeatedly) over time about models and people who get excited about long range forecasts, take a look at this comparison of the GFS 850mb winds from runs at 00z yesterday and today, for Friday the 24th at 8pm:

Swipe left to see current forecast (no storm), swipe right to see yesterday (with storm)

So the various blogs and weather channels that spend a lot of time talking about this stuff are potentially getting you worked up for nothing and wasting your time (well, they are making money off of your fear and angst, but that’s another story).

Most invests and disturbances don’t ever become anything, and even a high formation probability can quickly drop to zero, just as one with a low probability can quickly spin up. Those odds are as much art as science. In either case, as I so often point out, no matter what anyone is saying, if the NHC Tropical Weather Outlook does not have the magic words “Interests <somewhere> should <do something>”, or if it does and you aren’t <somewhere>, then please don’t worry about it and switch off anyone who says you should. The same applies to a live storm – no mention of your area in the “key messages” graphic, no need to worry.

Here’s the current view of the situation in the Atlantic. The remains of Nicholas are still dumping rain in the US South, there is a system off the US East coast that will be generating high surf (and rip currents) across the coast, but if it spins up looks to stay offshore. NHC sent in an airplane yesterday – it didn’t find anything – and will do so again today given how close it is to the US coast. As for the thing off of Africa (AL95), satellite data isn’t showing significant development yet, but it does have potential to become a tropical cyclone. Here’s the TAFB situation map for the Atlantic this morning:

Click to embiggen;

Chanthu is slowly moving away from the China coast off Shanghai, and will be sweeping across Japan as a weakening system. Mostly a rain threat at this point. Elsewhere it’s fairly quiet for this time of year …

If you aren’t familiar with weather maps and symbols, here is a video primer (link) from the Univ of Illinois, and a web primer from NOAA (Link).

#Ida continues to cause damage, #Larry the cable guy

The remnants of Hurricane Ida (now a “Post Tropical Cyclone”) continues to cause damage across the US Northeast as it finally moves offshore. That, combined with the ongoing power outages, is increasing the economic impact total for the storm, which is now probably over $55 Billion USD and moving Ida into the top five storms in US History.

Hurricane Larry continues to develop in the eastern Atlantic. While it may be a factor for Bermuda and trans-Atlantic shipping, it’s mostly a Cable TV news/weather channel storm. Why is that? Here is this morning’s surface analysis map from the US Weather Service’s Tropical Analysis and Forecast Branch:

TAFB map of the Atlantic, Thursday 2 Sept 2021. Click to embiggen.

In the upper right is an “H” indicating a big high pressure system. Air circulates clockwise around high pressure in the Northern Hemisphere. That is pushing the storm at first west, then it should turn northwest then to the north and northeast as it rounds that mound of air. That, combined with the projected interactions with surrounding systems like the cold fronts headed to our coast (jagged line across the eastern US) should combine to keep the storm offshore.

Here’s the infamous “spaghetti map” of tracks generated by the various computer models. As a reminder, the colored lines are the primary track models – the “cloud” of gray lines are mostly ensemble members – alternative scenarios, many of which are not realistic, but are generated to provide context and probability. Remember the pasta must be cooked before eaten …

Computer model tracks (and NHC track in red).

The longer term models (such as the GFS and EMC) both take the storm well off shore longer term. So again, your best source of information on hurricane threats for a live storm are the National Hurricane Center’s “Key Messages” summaries. In the case of Larry, it’s no threat land so there aren’t even “key messages” at this point, so you’ll have read the public advisories.

Atlantic Storm Watch (#Ida aftermath, #Larry)

First a bit of good news, it seems the critical LOOP oil terminal survived hurricane Ida, and while there will be weeks of recovery ahead, the oil and gas infrastructure does not seem to have suffered any critical damage. The bad news is that the electrical grid is in shambles, which will slow down recovery (including getting the refineries back online). Worse, it will be hot and muggy the next few days; the entire disaster area has high heat warnings today …

Heat (HT) and Flash Flood (FF) warnings, Wed. morning. Click to embiggen.

Elsewhere, in the far eastern Atlantic tropical storm Larry has formed. Like Ida it is headed for an area ripe for rapid intensification, and is expected to be a major hurricane within three days. Fortunately, it should turn north and stay well away from land (those in the US shouldn’t freak out it seems to be curling towards the US in this map, it’s an artifact of projecting the globe on a flat map, and Larry is *way* out there!). There is also a new invest area in the Caribbean (AL91). Development over the next five days is currently projected at 20%, but it’s in a scary place given Ida’s track, but more than likely it should drift west towards Central America as a weak system.

Hurricane #Ida pre-landfall analysis for #NOLA, #LA

Long time followers know I’m usually one of the few voices saying “this is hyped and won’t be so bad.” Not this time. Sure, CNN got the meteorology/hydrology wrong, and many of the other media are rather unseemly in their excitement, but this is a dangerous and devastating storm, and things are potentially dire for New Orleans (NOLA). Here’s the increasingly bad news. First, the storm itself. As expected, Ida moved into an area nearly perfect for rapid intensification, and the only potential inhibitor, some dry air to the south, stayed out of the circulation. It is now a mature Category Four hurricane, and is likely to stay that way up to landfall late this afternoon.

Ida is now within range of land based radars. Here is the view from Slidell, LA (just east of New Orleans) at 5:20am. Any image may be clicked to enlarge. The left is reflectivity (rain) showing the eye and bands (some of the outer bands are already reaching NOLA), the right is the doppler velocity. In the fine print in the upper left hand side of the doppler side of the display is the peak wind speeds – the radar is seeing a peak 121 knots (139mph) at the altitude the radar beam is passing through the storm (several thousand feet).

The forecast shows Ida making landfall just west of Port Fourchon, with the eyewall sweeping across the western suburbs of New Orleans – Kenner, St. Charles, Laplace. Even a small wobble, well within forecast uncertainty, takes the eastern (stronger, right hand) eyewall right across the city. Wind damage is likely to be epic in either case. Here is the forecast swath:

However – on this track, storm surge flooding in NOLA is actually less likely as the storm surge from Lake Pontchartrain should be pushed parallel to, then away from the levees. This is something CNN’s weather people got consistently wrong yesterday; New Orleans is a bit backwards in that the worst case for flooding is with the storm passing just *east* of the city (to the right). Yes, that places the city in the “weaker” eyewall – but it means the winds blow the water directly into the city. I’ll try to do a post on that today. It’s an interesting situation, one that anyone familiar with tropical meteorology risks in the US is well aware of, and it’s disappointing (but not unexpected) that they don’t know that. How likely is that scenario? Unfortunately it’s a lot more likely than it was yesterday. The track has been shifting eastward, and the satellite and radar fixes this morning are right (east) of the forecast track as well. That’s bad as it places the stronger eyewall across the city, resulting in more wind damage – and if it results in a passage just east of the city, storm surge could well overtop the levees. On this track Ida is forecast to be a $40 to $50 Billion dollar storm, just below Sandy for the #5 spot on the US “costliest” list. But a eastward wobble with the eyewall crossing the city (and a refinery or two breaking), Ida could easily be up there with Harvey, and Katrina in the $100 Billion dollar club. If a levee or the pumping system fails, we could well be looking at the most costly storm in US history. Given the disjointed evacuation process (it’s only voluntary in NOLA), it will likely be deadly as well.

Oil and Gas: on this track and intensity, something like 12 to 15% of US refinery capacity will be offline for at least a month. A lot depends on how strong the storm is when it passes over Baton Rouge and the huge ExxonMobil Baton Rouge Refinery. At 520,000 BPD, that one facility represents almost 3% of US capacity. It is in partial shut-down now to prepare for the storm, which is expected to still be at hurricane force as it passes over Baton Rouge. There is well over 1 million BPD of capacity at high risk from this storm. So much depends on how rapidly the storm decays after landfall – and how well the surrounding electrical infrastructure providing power to them survives. That, and you need people to run these things: if the surrounding communities are devastated, even if the facilities survive with minimal damage the workforce will be in bad shape. Here are the major refineries in the swath …

Down at the bottom of the above map is a label, “Louisiana Offshore Oil Port”. That is a vital bit of infrastructure. Through that platform passes over 10% of US oil imports, and its pipelines are connected to the major refineries inland. The offshore facility will be experiencing waves over 10 meters (30ft) and winds well over 120mph in the coming hours. It is likely to be offline for some time.

This is going to hurt at the gas pump for a while.

#Henri falls apart

Tropical Storm Henri really fell apart this morning before landfall. Here’s the radar view from Boston at 11:44 am …

Reflectivity on the left, doppler velocity on the right.

And the GOES East satellite view at roughly the same time (11:46 to be pedantic) …

as usual, click to embiggen. Winds are well below hurricane force, and aside from some rain bands and gusty winds, unless you’re just unlucky this may turn out to be a non-event.

Update on #Fred, Wed. Afternoon

Short version: no significant changes in this morning’s notes.
Long version: after a comprehensive evaluation of the current NHC guidance and all of the available data, including satellite radar, radiances across the spectrum, nearly two hundred different computer track models, and augury according to the Ancient Practices, there is really nothing new to say about Fred. So here’s a pretty picture of the storm making landfall in the Dominican Republic …

Click to embiggen.

By tomorrow we’ll know how Fred did crossing Hispaniola, which will be something to discuss. For the latest official word, Key Messages regarding Tropical Storm Fred (en Español: Mensajes Claves).

There also isn’t anything new to say about the tropical waves in the Atlantic, other they they may or may not spin up. Yes, one is an “invest” but that’s just something to give the models a consistent ID to track. It never really pays to worry about tropical waves or invests until they get organized. If threatening land, NHC will call them a Potential Tropical Cyclone and start advisories (as it did with PTC6/Fred), and then they aren’t invests any more.

Tropical Storm #Fred Wednesday morning Update

Over night Potential Tropical Cyclone Six got itself organized enough to become Tropical Storm Fred. The latest from the US National Hurricane Center is here: Key Messages regarding Tropical Storm Fred (en Español: Mensajes Claves). The TLDR is Fred is just a tropical storm. That means it is mostly a rain event, flash floods, mudslides on steep slopes on the Islands (Puerto Rico, Dominican Republic/Haiti, Cuba). Minimal wind damage. For the mainland US, some rain, a few wind gusts are all that seems to be on tap. Here’s the details …

This morning there are a few more rain bands around Puerto Rico as the storm passes by on it’s way to Hispaniola (Dominican Republic/Haiti). Here’s the radar and GOES satellite view at just before 6am ET:

Click any image to embiggen.

The Local Storm Reports from San Juan this morning indicated one man swept out to sea in rip currents, but aside from some localized flooding and power outages (the island’s electrical grid is extremely fragile) there does not seem to be extensive damage.

Fred is on track to rapidly pass over Hispaniola today. The mountainous terrain will prohibit any strengthening despite an otherwise favorable environment, and in fact it’s likely that Fred will decay to a Tropical Depression (peak winds below 34 knots/40mph). There will still be a lot of rain, which could be a problem in Haiti as flash floods and mudslides on the unstable, heavily populated slopes are always a problem even in otherwise minimal storms. Given the political turmoil, not a good combination.

Here’s the damage swath from my TAOS/TC model, based on the NHC forecast:

Once back over water Thursday Fred should start to gain strength, but the proximity to Cuba will limit that – in fact if it tracks a little further south than the NHC track, down the spine of Cuba, it might break up all together. But the current forecast is for Fred to hang together, slow down, and cross the Keys as a minimal tropical storm Friday/Saturday, then track along the Florida Coast. Landfall in the US is expected next Monday as a minimal tropical storm – but that’s a long ways off. While the track is fairly clear until Friday, after that both track and intensity gets a bit fuzzier, and it could end up anywhere from running up Central Florida (the European Model) to Pensacola (HMON, HWRF). The good news is that all of the models, even the typically hyperactive HWRF, keep Fred below hurricane strength.

For the Coastal Georgia/SC area, despite the Cone of Shame (NHC uncertainty cone) creeping towards the area like a zombie invasion, any impacts are expected to be minimal unless something radical changes, as Fred will be a decaying “back door” storm at worst. Some rain, maybe a wind gust or two, a few leaves down, random power outages – just like any other summer day. There’s really no need to wear out your refresh key unless you’re south of Orlando, where tropical storm watches will likely go up for the Keys tonight.

PTC #Six (AL062021), probably will be #Fred but should not be more than a tropical storm

TLDR: the system is near Guadeloupe, will bring heavy rains to the USVI/BVI/Puerto Rico area later today, perhaps as a minimal tropical storm. Main risk is flash flooding. After that, it should track across the Greater Antillies (PR, Dominican Republic/Haiti, Cuba) then things get fuzzier, but probably up the west coast of Florida, most likely as just a tropical storm. Yes, the Cone of Shame (NHC Uncertainty cone) may creep into Georgia today. No need to panic yet. Here’s the details …

As a reminder, your best bet on the official forecast is NHC’s Key Messages regarding Potential Tropical Cyclone Six (en Español: Mensajes Claves). It’s a great summary for active storms, and tells you in one easy to read graphic where it’s going, how bad once it gets there, and where the watches/warnings are located. For PTC6, tropical storm warnings are in place for Puerto Rico, the Virgin Islands, and the Dominican Republic, and watches for the north coast of Haiti and the southern Bahamas.

Here is the forecast swath using my TAOS/TC model. The map key uses “plain English” descriptions of the impacts, and computes the potential economic and humanitarian impacts of the storm. In this case, economic impacts are not expected to be great, under $25 million, with just under 4 Million people within the range of tropical storm force winds through day 5 (Sunday). The main impacts based on this forecast are flash floods in the mountainous terrain of the Greater Antilles.

Swath o’ Doom: click to embiggen

The storm is currently classified as a “potential tropical cyclone” (PTC) rather than a tropical depression. That is because while the storm does not have a closed circulation and structure of a tropical cyclone, it should develop those characteristics today. By then the outer fringe will be impacting the Virgin Islands and Puerto Rico, so NHC uses the PTC designation to allow them to start tracking the storm and issuing forecasts, including watches and warnings, using the same methods as a tropical storm. This may seem like an administrative dodge or detail, but a lot of procedures and processes get triggered this way that wouldn’t otherwise if the storm were treated for what it is. Nature doesn’t like bureaucracy any more than anyone else, but the pointy haired bosses of the world usually figure out a way to make it fit 😛

Here’s the view this morning – visual is dark since the sun isn’t up yet:

Satellite view: IR (cloud top temperatures) on the left, visual on the right

The current forecast track has PTC6 (which by this time will probably be Tropical Storm Fred) deteriorating to a tropical depression as it passes over Hispaniola (DR/Haiti). While the general track for the next three days is fairly straightforward, what happens after that is a bit fuzzier, especially with respect to intensity, but the forecast is for it to regenerate to a tropical storm as it moves offshore over the Turks and Caicos and threads the Florida Straits into the Gulf of Mexico.

The chattering class will be speculating what happens after that as the “Cone of Shame” (NHC’s uncertainty cone) begins to extend up into the Southeast later today, or people who don’t know any better try to read the tea leaves left by the long range models. It is vital to realize that all parts of the cone are not equal, and the long range models require a lot of experience to interpret beyond simple lines on the map. Working on a post on that … meanwhile, at this point there is no significant threat to Georgia/SC, maybe some rain and gusty winds next Tuesday (the 17th) from a “back door” storm as it falls apart after landfall, but it’s way too early to speculate (not that will stop anyone).

NHC Starting Advisories on PTC#6 at 5pm ET

The National Hurricane Center is starting advisories on Potential Tropical Cyclone (PTC) Number 6 (AL062021) at 5pm ET. This is what was invest area AL942021, approaching the Leeward Islands (Guadeloupe, Dominica, Montserrat) on it’s way towards Puerto Rico and the US Virgin Islands. NHC is starting advisories as a “PTC” even though the system isn’t technically a tropical system yet so they can start issuing watches and warnings, and get things in place since by the time it does it will be close to those areas. Here’s the 4:30pm satellite view …

If you’re in the islands, check the advisories, and prepare for a tropical storm. If you’re in the US, nothing to freak out over at this point – the track will most likely be towards far south Florida, but most likely as a minimal tropical storm, and it’s way too early to get excited about if you have a hurricane plan. More in the morning …