Dramatic Michael Update! (ok, that’s clickbait, nothing changed significantly since this morning but here’s some pretty pictures).

The forecast from NHC at 11am really didn’t change significantly other than some tweaks in the track and intensity.  Watch and warning areas didn’t change, Damage swath, damage estimate from my Haetta/TC model didn’t change much at all.  Timing a little slower inland.  So, if you’re getting ready for a Cat 3 hurricane (and if you’re in the warning area, especially around Panama City, you’re an idiot if you aren’t), or in inland Georgia getting ready for some high winds and rain, keep doing that.  See the earlier post for details.

Here’s an animation of the GFS model. Click to get the full loop.  I hate these things.  Sure, they are dramatic and pretty, but they don’t tell you much of anything about potential damage or who needs to be afraid and who needs to just chill …

And here’s a visual band image of the storm.  Got an eye, and may strengthen some more before landfall.

AL14 (Future Michael), Earthquakes, and other stuff

Several big events over the last two weeks, especially the earthquake/tsunami in Indonesia and the earthquake in Haiti yesterday evening.  And more Pacific tropical stuff.  Have been swamped with research stuff and will try to catch up over the next day or two, but getting lots of queries about the storm off of Belize so will say a few words about that first.  Here’s the noon Sunday satellite view …

Other than gusty winds, for the Caribbean threat is mostly to the west end of Cuba as the storm makes its way out into the Gulf over the next day or so.  The 11am NHC Advisory package for Tropical Depression 14, which will likely reach tropical storm status and be named Michael this evening, has landfall on the Gulf coast of Florida sometime Wednesday.  For those of you who just can’t live without your daily dose of pasta, here’s a look at some of the major forecast model track guidance guidance NHC was taking in to account in creating this forecast.  Some show landfall as far west as Mobile Alabama, some as far east as the “Big Bend” area of Florida, near Steinhatchee.  The big dynamic models bring the storm in as a Hurricane, so if you are on the Gulf Coast pay attention. The overall impacts depend a lot on the track – one of those “duh” things meteorologists like to say.  The further west, the more likely effects will be confined to the coast near landfall, and the storm will degenerate over land.  Further east, especially for a “back door” type storm that makes landfall on the Gulf Coast, exits or skirts the coast of GA/SC/NC, it’s a more widespread problem. 

Just a brief rant (again, sigh) about showing track models maps, especially those sites who show all of the individual tracks as the haze of lines.  Lets look at that brown line on the map above in more detail. Here is JUST the GFS Ensemble model and the members of that ensemble.  So in simple terms the way this works is that the model is run a number of times (in this case 20) using “perturbed” (different) initial conditions based on the uncertainty in the storm position and characteristics, with an averaging program run to get the average track.  The individual runs are interesting for understanding the uncertainty of the forecast, but treating them as “equal probability” outcomes is misleading – and it’s just plain wrong to go ZOMG THE AP20 RUN SHOWS A DIRECT HIT ON SAVANNAH as if that is a stand alone forecast equal to something like HMON or especially the consensus track models (much less the human-assisted official NHC track).  So I’ll say it again: be sure your pasta is cooked by a real chief and chew well before swallowing it 😛

NHC is more or less splitting the difference (as does the consensus model blend) and takes the storm over Panama City.   Fortunately we’re not looking at a Florence/Harvey kind of “move just lnland and stall” scenarios, this looks to be the typical “landfall and move on” 24hr kind of event.  Here’s the impact swath based on the official NHC track forecast (which, as I often rant, is the only thing you should really worry about) …

Notice how broad the wind field gets after landfall, and the big swath of 40mph+ winds that are offshore.  This is typical for a storm that accelerates rapidly after landfall.  For those in Georgia and SC, don’t freak out over maps like this that show the storm as a tropical storm well inland.  First, as you can see here, the strongest storms will likely be well away form the center, and mostly confined right on the coast.  Second, NHC tends to overestimate the inland winds from an impact standpoint.  (said in a different way, while it is true there might be a small patch of winds of tropical storm force 24 hours after landfall, it isn’t likely to be as widespread as models and graphics based on their forecast show).  That’s fine for planning purposes, but don’t get too upset over it just yet.  Again, small changes in this track can produce big changes in impacts, so watch for the official watches and warnings.  A direct hit on the Panama City area by a Category 1 hurricane could be messy – current impact estimates are around $4.5 Billion, but it’s so early that number isn’t very reliable.

Florence Update for Thursday, 13 September 2018

Florence continues to “barrel” (funny how some words get stuck in the media) towards the southern North Carolina shoreline.  The short version is that for the immediate landfall area, not too much has changed.  Watches and warnings are the same, expected “worst case” impacts haven’t changed, etc.  There is some good news in the sense that the storm may not be as intense as forecast when it makes landfall, it’s down to Saffir Simpson category 2 levels.  That DOES NOT mean those in the warning areas should fail to prepare for a Cat 3 – there could be a bump in intensity before landfall, but signs are for a weaker storm than expected.  Still, will be bad enough, so if you haven’t gotten out, do it this morning before conditions deteriorate rapidly later today.  Winds along the coast are light so far (looks like 10-15 knots peak right now), but that is going to change rapidly.  Here’s a composite radar view from the two closest sites (Wilmington, range indicated in white, and Morehead City, range indicated in green).  Classic eye and banding structures becoming visible …

The various forecast track models and other simulations are in pretty good agreement that the storm will make landfall, then stall out for at least two days near the SC/NC border, over the Grand Strand. Here is the impact estimate based on the official NHC forecast as of 5am this morning:

This is the tricky part of the forecast – if it’s on the shore, or near the short, it can maintain intensity, and pump more rain inland.  If it’s even 50 miles further inland, the intensity and rain rates will drop off pretty quickly.  On the current track, the worst wind damage will stay in North Carolina.  Direct impacts should be around $10 Billion.  The big question is rain and flooding.  The current estimates are for about $5 Billion in additional impacts from rain related flooding.  But a longer pause could double that number; likewise, if the storm is even 50, much less 100 miles inland, that could easily drop to a Billion or so.  It’s a great unknown …

For folks in Savannah GA and the Beaufort/Hilton Head area, things look pretty good on this track.  We’re on the weak, dry side of the storm.  Winds will be offshore, so storm surge flooding will be nothing to worry about.  Right on the coast, waves and wave setup might cause some issues, and rip currents will remain dangerous.  Depending on wobbles, we may get rain, or just as easily get a clear if breezy day in the subsidence zone.  But dangerous conditions (other than on the beach) just don’t seem to be in the cards right now.

Florence 11am ET Update: No changes to official track, models shifting again …

For more detail on model tracks and why you shouldn’t focus on them, see my post from earlier today.  But if you need an example, let’s look at the changes over the last 6 hours in just one global model, the NCEP GFS model, in comparison to the official forecast track (which didn’t change):

The official track didn’t change very much.  Still looking at the same folks who should be evacuating by now, same watch and warning areas, same damage estimate (around $15 Billion).  Here’s the map:

So for people in southern South Carolina, and especially those in Georgia, I again say don’t eat poorly cooked pasta.  It will give you indigestion …

Hurricane Florence: a deeper look at track models (Wed. Morning, 12 Sept)

This is another long read, with some SCIENCE!, but the details of this matter – I hope you will be patient and read on.  While I often touch on hurricane track forecast models, I normally stick with the official NHC forecast track when discussing the impacts of storms.  There are a lot of good reasons for doing this.  First, track forecasting is a very specialized profession, with a lot of complex factors involved.  NHC has specialists to do that, and while I sometimes disagree with details, they are very good at it. Interpreting the multitude of track models is not an easy task.   Second, given it is their responsibility to do official watches and warning, diluting their message to the general public is not a good idea.  Some may say this is a bit hypocritical on my part, given my criticisms of Emergency Managers and evacuations, but there is a key difference – NHC are professionals who consistently do a good job.  Governors issuing evacuations orders have a much spottier track record, in my clearly not so humble opinion 🙂 , so I feel free to trash them.

Unfortunately, there is a trend in the media to talk about specific track models at the expense of the official forecast, and to publicly second guess or anticipate the next NHC forecast.  Part of this is because beautiful, dynamic animations are available for individual track models.  These graphics are great for TV, and the temptation to show a graphic that passes over or near your viewing areas is overwhelming.  But it can also be very misleading.  So let’s take a closer look at track model outputs for Florence, and what they mean.  Here’s the track model map available at about 4am this morning:

The Global models (exemplified by the dark blue GFS line show the storm pulling up short of the NC shoreline before diving south.  The dedicated hurricane models such as HMON (the replacement for the GFDL, shown in light green), the HWRF (shown in light blue) and the official track (red lines) don’t have the sharp right turn.  There are a lot of reasons for this.  For the objective models, it is important to realize that while they are often good at forecasting hurricanes, and are used to provide “boundary” conditions for specialized models, they are not specialized, high resolution track forecast models. They often lack the detailed coupling to ocean models, and have less sophisticated model physics than the dedicated models.  This gap has closed in recent years as global models have gotten better, but the gap remains.  In their forecast package development, NHC takes in to account factors like this using their involvement in, and detailed knowledge of, these models.  They also realize that models can shift radically from one iteration to the next.  Every 6 hours, data from weather stations and satellites is collected globally and used to create a picture of what the atmosphere looks like at that time.  These are the initial conditions.  Those initial conditions are then used to spin up the global models, as well as the dedicated tropical cyclone models.  That’s the simple version, but the details are very complex.  Not all initial conditions are created equal.  One small example: the 00Z (8pm ET) and 12Z (8am ET) initial conditions are often “better” than the 06Z (2am) and 18z (2pm) data sets.  This is because most upper air observation sited only launch two balloons per day, at 00 and 12z.  Sometimes you get a satellite pass over a storm at the right time, sometimes its 3 or 4 hours earlier.  Sometimes you have airplane data, sometimes not.  So when I fuss at meteorologists, weathercasters, and storm watchers for latching on to a model shift, that’s one reason why.  It’s also why the NHC sometimes seems slow to shift tracks to follow what seems to be shifting model data – they realize that it can just as easily shift back 6 or 12 hours later.  There is much more to it than this, but I hope that gives you at least a glimpse into the fact this isn’t simple, or for amateurs.

Another factor is that the storm isn’t just some line on the map: it’s a broad, complex system.  Let’s look at the impact from two very different model simulations.  Here’s the HMON run, and for comparison, the CTCX run, which shows the storm hitting Savannah, GA …

Note especially the impacts onshore.  If you compare the areas of severe impacts, despite the fact that the track line is scary for people in Savannah and southern SC, the dangerous, life threatening impacts are all contained within the warning areas NHC has set.  Now here is the impact estimate based on the official track:

What about economic impacts?  On the official track we are still looking at about $12 Billion in direct impacts.  The HMON track would product “only” $5 or $6 Billion, while the CTCX track would likely cause $3 or $4Billion, because the stronger winds would stay offshore!

And what about the infamous “cone of uncertainty?”  I see people making much of this or that city being “touched by the cone.”  Well, to be honest, who cares.  I hate that graphic.  What you should care about is how strong the storm will be if and when it gets to you. As NHC notes, bad impacts can exist outside the cone.  But the opposite is also true.   If the death cone touches you on day 5, when the storm is inland and barely even a tropical depression, and you probably wouldn’t even know it was a storm if somebody didn’t tell you, so what?

So despite all the rending of garments and gnashing of teeth, because of the intensity of the storms on the scary scenarios showing a turn along the coast, the storm would weaken fairly radically, and the impacts would be less.  So the conservative path for NHC is to continue to slowly shift the track south (assuming the forecasts continue that trend), adjust the intensity accordingly.  And, as you can see, the present watch and warning areas are in fact perfectly fine for this storm.

Bottom line: yes, the forecast tracks are shifting. Yes, forecasting is not an exact science. But it’s not really as big a deal as some would like to make it out to be.  Stay cool …

Florence Evening Update for Tuesday 11 September 2018

First some advice.  Don’t freak out over any one computer model forecast, and be skeptical about folks who show you dramatic graphics and talk about tracks while not discussing the official National Hurricane Center forecast all that much.  Tropical Cyclone Forecasting is specialized, and understanding all of the nuances of track models takes a lot of experience.  Most of what you read here is either an interpretation of or derived from NHC forecasts using my active research work on natural hazard damage models.  While I work on forecast models of various kinds, and have a deep understanding of numerical weather models, for the most part I leave that end of the business to the folks who do it every day.  Why are my discussions often less dramatic than other sources?  Probably because my income doesn’t depend on hits, viewers, or selling you stuff 🙂  But let’s start with the obligatory dramatic satellite picture anyway …

As usual, lets will look at the track, the likely impacts on that track, followed by the implications of those impacts in both economic and human terms.  This is a bit of a tough forecast situation.  There is a high pressure ridge to the north of the storm that is currently guiding it towards North Carolina.  That should control the motion for the next two days (until Thursday).  But then things get a bit less clear.  This morning, most indications were that a “weakness” in that ridge would cause the winds steering the storm to slow down or even stop as it makes landfall over North Carolina, drifting for a couple of days, then begin to move northestward, dumping a bunch of rain in the process.  Today, however, the dramatic ECMWF model runs making the rounds in social media show the storm “bouncing” off the high and moving SW,  showing Florence heading south and perhaps even hitting again as far south as Georgia.  Most models, however, just show some kind of jog  offshore rather than just inshore as was the case this morning. So the big picture is more or less the same Here’s some of the track models as of 4pm this afternoon (ECMWF isn’t shown for licensing reasons) …

So what does all that mean?  Well, let’s see what the experts have to say.  Here is the 5pm NHC forecast track.  I added in the 5am track from this morning in yellow for comparison.  Not so different, huh?  From their forecast discussion, “there remains no significant change to the previous forecast track or reasoning.” 

So what’s the bottom line? No major developments. The areas under watches/warnings/evacuations are not changed. The damage estimates are about the same – somewhere around $14 Billion in direct damages, flood damages highly dependent on exactly where Florence stalls out and how much rain gets dumped.  Folks in the immediate path of this thing should get out of the way.  IF the storm does do the stop and turn shown above, that’s good: it will be weaker, and cause less damage.  If it follows the ECMWF scenario, it will almost certainly not be in very good shape as storms don’t like to run in to walls of air and get shove at a 90 degree angle … so there is still no need to panic, just keep watching the official forecasts, smile (and don’t make any sudden moves) at folks who are freaking out and latching on to every weird variation in this complex situation, overreacting to pretty pictures, and stay cool …

Florence: NC most likely landfall as Category 4 on Thursday/Friday

Today is a major day for decision and action as Florence is clearly headed towards North Carolina.  Here is the current NHC forecast track (read with hurricane symbols), with the estimated damage zones based on my Haetta/TC model.  Also shown, in yellow, is the official forecast track from yesterday morning.  For all of the talk of uncertainty and track models among the chattering classes, the official forecast has been remarkably consistent:

Notice the area of catastrophic, severe, and widespread damage. Seems small, given the talk, doesn’t it?  The thing to keep in mind with hurricanes is that the swath of actual severe damage most times, even for a major hurricane, isn’t all that wide.  Media folks love to talk about how big the cloud shield is, or the extent of the over water tropical storm force winds, but for Florence, severe effects will extend about 120 miles to the right (north) of landfall, and 80 miles to the south.  Of course the problem is we don’t know exactly where that 200 mile wide swath of damage will be in 3-4 days when it hits, thus the 600 mile wide watch and warning zones.  Don’t be mislead by fluctuations in intensity, or brief north or south wobbles.  For example, this morning the storm is going through an eye replacement cycle.  It may even be a cat 5 at times.  Along the coast the damage will be epic if the storm stays as strong as it is. 25, maybe even 30 foot storm surges in places where the water can pile up.  Even inland, damage will be severe, with trees down and structures damaged.  But especially scary is a detail in that map: notice that landfall is expected in 3 days – then the storm moves only 50 or 60 miles over the next two days.  While the intensity will drop quickly after landfall, enough of the circulation is likely to remain over water to pump immense amounts of moisture over NC and VA.  That means the potential for tremendous inland flooding.  If you live near a creek, stream, or other flood feature, be aware that the waters may rise quickly.  Local knowledge is everything in this kind of situation, but with so much water, and so much development (which changes radically the hydrology of an area) areas that have never flooded will probably flood.  Comparisons are being made with Harvey.  That may not be far-fetched.

My damage models are still showing approximately $20 Billion in damage, with as much as $15 Billion in additional flood damage possible depending on variables like how long the storm sits and now much rain is dumped into Virginia.  Florence is definitely on track to enter the top ten most damaging storms.

At this point it is fairly clear who needs to take clear, decisive action.  NHC has issued a hurricane watch for the coastline from Edisto Beach SC to the NC/VA border.  I expect a watch or warning of some kind for parts of Virginia today are possible depending on minor track shifts and timing.  Especially for those in Myrtle Beach and the northeast corner of SC, and all of eastern North Carolina, the hyperbole isn’t really that wrong here.  If on the coast, or in low lying areas, get out.  If within 50 miles of the coast in anything other than a substantial structure that you know can stand up to high winds, get out.  If you are in the NHC watch areas you really need to take action and be gone before Thursday morning.

That said, I again want to point out that for far southern South Carolina, south of Edisto Island, the risks are decreasing rapidly other than for rip currents and waves right on the beach in the surf zone.  For Georgia, the risk at this point is vanishingly small.  It will probably be a nice day as we (I live in Savannah GA) will be in the subsidence zone at the fringes of the storm, but don’t plan on going to the beach and swimming, as again waves and rip currents will be dangerous.

Florence update, Monday evening, 10 Sept 2018

No doubt about it, Florence is truly a monster category 4 storm now, here the eye seen at 5pm  …

So the questions are, as usual, where is it going, how bad when it gets there, and what to do?  Where is more or less clear.  The track guidance is fairly well clustered on the lower NC coast, and has been shifting a bit northward during the day.  Note the blue track of the NOAA GFS model doing a loop offshore.  That’s not a glitch – that could really happen, although it’s not likely.  Here’s the latest map using tracks available as of 4pm or so, with the latest NHC forecast track in bright red (the previous track is in darker red) …

How bad?  Pretty bad.  Here’s the forecast damage swath, using the official NHC forecast track.  The track didn’t shift that much during the day today, a little bit north, but the broad swath of impacts still covers much of the northeastern corner of South Carolina and all of Eastern North Carolina.  Storm surges could easily be in the 25 foot range in places.  Damage along the coast will be catastrophic if the intensity holds, with severe damage as far inland as the Research Triangle area.  

On this track it’s a $20 Billion dollar storm at least, with many estimates coming in at $25 to $30 Billion.

As for what to do, this is a seriously bad storm.  If you are in on the coast of South Carolina in or north of the Charleston area, or North Carolina, you need to evacuate.  It’s a no brainer.  Get out, and if inland in a secure structure, button up.  If in mobile homes get out even if inland.  You really need to listen to local emergency management on this one, hyperbole aside, it is a very dangerous hurricane.


For the Georgia and far southern SC coast (Beaufort/Hilton Head), the bad impacts will likely all be to the north, and the risk decreases with every hour.  This raises an interesting (and tough political) question, given the state boundary between SC and Georgia.  The Governor of SC has ordered mandatory evacuations for all zones for the entire coastline.  So we have the odd situation where people on Tybee are under no instructions to do anything, while folks across the river who they can literally see are being told to flee for their lives.  One of my complaints about the way evacuation decisions are made is that they are often set up as canned responses with little room for flexibility.  There are a variety of legal and operational reasons for this beyond the scope of this post.  While there is some coordination between the states, most of these decisions are stovepiped, and given the different political considerations in each state, along with different skill levels and experience of personnel, things like this happen.  To folks in Georgia, don’t freak out.  While you should carefully listen out for a possible change of direction, again the risk is decreasing.  For people in the Hilton Head area, you have a choice to make – follow the directions of your emergency managers, or take a chance, given the odds are likely very much in your favor since it would take a pretty radical change in track to bring life threatening condition to your area?  In general I support following the advice of local EMA’s.  Here, I personally think a more targeted approach would have been appropriate.  I can absolutely see getting ready to evacuate special needs populations, etc. I can see putting the communities on notice.   But a general evacuation carries risks – evacuating Sun City and HHI will very possibly kill some people due to stress, traffic accidents, etc.  It risks clogging up the roads and  taking up hotel and shelter space for people who absolutely must get out of the way.  Unfortunately, this is a discussion that tends not to happen until a storm is “barreling” into the coastline, and it devolves in to a “follow evacuation orders or die” kind of thing.  We need to have a nuanced discussion about this, and some better planning and coordination at the *national* level.  That said, the bottom line is that EMA’s are often a bit conservative, and sometimes have operational, political, and legal considerations that aren’t always in the best interests of every individual, but for the most part they are trying their best and deserve your respect and attention.  In this case in the far southern counties of SC (Beaufort, Jasper) those other factors might be in play.

Sunday Morning: Florence decision time approaches

Things actually didn’t change too much overnight, and I’ll post a full analysis as the 11am NHC package is released since that will be used by most emergency managers for decisions today, so here’s some thoughts on information sources and the process. I want to again caution everyone using social media like Facebook: the Facebook algorithms do not show you posts chronologically, but by popularity!  Be absolutely sure you are looking at the most recent information!

As decision time approaches for taking action on Tropical Storm (likely to be a Hurricane again some time today, possibly this morning) Florence, it’s time to review some information sources and toss out some words on the overall storm response process.  First, information.  There’s really only one source of hurricane track and intensity forecasts: the National Hurricane Center. Your best bet, quick overview, TLDR product is the “Key Messages” graphic.  Here’s the one for Florence.  If your local TV folks are scaring the beejesus out of you, go check the NHC site and see how closely their big picture message matches the NHC message and if not, go somewhere  else.

Everybody uses NHC’s products as a starting point.  The problem is that increasingly other people with far less experience and expertise, especially in the news media, are using the raw track forecasts and data to put their own opinions out there and diluting NHC’s message. Was watching CNN yesterday, and they spent only about 10% of the air time talking about the NHC track and reasoning and the rest talking about track models.  That’s irresponsible – the emphasis should always be on the NHC forecast.  On social media I see people with zero tropical cyclone experience talking about this or that model.  It’s interesting and exciting to discuss the models, especially beyond the 5 day limit of the NHC forecasts.  But NHC only forecasts to five days for a reason, and if someone can’t answer basic questions like what are the components of the TVCN model and what is its current 96 hour cross-track error as of the latest forecast package ( 103 nautical miles if you’re curious), laugh condescendingly and move on.

It is important to realize the roles various parties play in this process, and what their agendas are.  Of course everyone wants you to be safe – but they also want other things and it’s important to realize what those things are, and how it influences their point of view. NHC’s purpose is forecasting with an eye towards issuing watches and warnings.  They want to be “right” – but they also really really don’t want to be “wrong.”  This means they tend to be “conservative.”  What does that mean exactly?  It means they would rather, on average, overestimate things like storm wind speeds and impacts, because they don’t want people to be surprised by a worse storm than predicted (which potentially leads to more casualties and congressional hearings).  So you will often see NHC use the phrase “forecast of least regret”.  However, they are of course aware of that, and strive for a balance.  It’s a tough job.  The bottom line here is that NHC has the best mix of experience and resources to make those watch and warning calls.

Unfortunately, the people involved in the actual evacuation decisions are a) less experienced and b) often have political, legal, and experiential biases that lead to problems.  Key among these are two trends: politicians (especially Governors) making evacuation decisions, and local emergency managers coming from a law enforcement rather than a civil defense background.  I ranted a bit about this in a Facebook post this spring if you’re curious.

The News Media also has some biases and agendas that make information from them sometimes problematic. The first is they want to have a local focus.  That’s great, but in a situation like Florence the stations in each market want to talk about what would happen if the storm hit their viewing area.  So if you review the weathercasts from outlets from Jacksonville FL to Wilmington NC, with a few exceptions you’d think the storm was headed to each one, without a lot of perspective on what the probability of any given area being hit.  The time limitations of newscasts just doesn’t allow for that kind of nuance, even if the on air meteorologist had that kind of background and experience.  Weather is a key “grab” for local markets in the competition for market share.  So they want to make their weathercasts flashy, interesting, and make you want to come back for more.  It’s not that they want to intentionally mislead you, but in their efforts to play on your emotions to make you stay tuned, download their app (which are designed as much as marketing tools as information sources – be very careful with them as they often siphon off your contact lists, browsing history, and other privacy related info!), combined with the time limitations, the net effect is that they are often quite misleading as to the actual likely impacts of a storm on you personally.

The net effect of all this is that NHC is conservative (which is reasonable), emergency managers exaggerate a bit to try to get you to take action and follow their directions (I have a problem with this), Politicians often want to use disasters to make themselves look authoritative (this is disgusting), your local news media is basing their reports towards the dramatic (this makes me want to beat up grass), so the information you get is not just worst case, it’s often blown completely out of proportion across the board to the point where the message that needs to get to people who are often at real, life threatening risk is diluted, and the risk to everyone else distorted.

So what about Enki Research?  As a scientist, I’m looking for some kind of objective truth with respect to the economic and humanitarian impacts of hurricanes.  In my analyses, I don’t care so much if I’m high or low on any given storm, only that on average over many events (and note I often analyze 50 or 60 storms and dozens of earthquakes a year), that the errors in the estimates of economic and humanitarian impacts are minimized.  This is very different from virtually every other analyst you are likely to encounter outside the academic world, especially available to the general public.  As noted above, most other sources have a built in bias towards the high end on impacts – they would rather overestimate the impacts than underestimate them.  But that carries with it some risks.  Overwarning (“boy who cried wolf” effect) is one, increased economic impacts are another.  In one sense I don’t care if you read this or not (in fact, I sort of wish you wouldn’t so I could just do research and not have to spend an hour typing up this crap!).  But I’m also glad folks find it helpful, and as long as you, the unwashed masses 😛 want me to continue posting my analyses, I will …

#Florence Track Notes for Saturday 8 Sept 2018

First, a reminder of a great “one stop shop” for the official word on what a given storm is up to, the National Hurricane Center’s “Key Messages” graphic. It’s pretty straightforward, to the point, and part of the official package on a storm.  Worth watching.

Anybody remember the days when hurricane forecasts only went out three days, and the forecast track models were labeled “for intergovernmental use only”?  It’s great that more data is easily available for both researchers, planners, and the public alike, but it’s also fostered a cherry picking attitude among some who are at least as concerned with hits, viewers, and visuals as they are with accurate forecasts, and for the vast majority of people (including most TV meteorologists and government officials) these things can be scary if you don’t know how to interpret them.  Here’s the forecast track model map as of this morning; some important models are highlighted, as is the official NHC forecast:

Interpreting “spaghetti maps” takes years of training and experience.  It’s one reason why you should be watching that red line (the official NHC track) and not worrying so much about all the other clutter.  It’s like going to the doctor – you have lab work with all kinds of scary numbers, MRI scans, etc.  What matters, and what doesn’t?  It takes an expert.

With hurricanes there are always two related questions: where is it going, and how bad will it be when it gets there.  We’ve gotten somewhat better at the “where is it going” (although better is a relative term; average day 5 forecast errors for the official forecast are around 200 miles). For Florence, there is a big question about the steering Tuesday and later.  There will be high pressure to the north and east of the storm.  Exactly where and how strong is uncertain, and that is causing the reasonable day 6 (Thursday)  forecast location to be within a 800 mile wide swath ranging from the GA/SC  border to out between NC and Bermuda!  The “how bad” part is even harder.  Florence is currently a tropical storm.  It should strengthen, and could be as strong as a category 3 storm at landfall.  However, intensity is tied closely to track, so with so much uncertainty in the track, the intensity forecast is also uncertain.

So what’s the short version as of Saturday AM?  Florence has the potential to be a bad storm for somebody on the US East Coast, Bermuda, and/or Canada later in the upcoming week (Wed/Thu/Fri).  Most likely estimate at this point for hazardous impacts is the North Carolina coast, with points northward (DelMarVa, etc) also likely to see impacts, but South Carolina is not out of the question, and even the Georgia Coast in theory is within the “cone of uncertainty.”  HOWEVER, the storm is still beyond the range of the primary hurricane models.  Forecasts beyond 4-5 days are fraught with error.  For technical reasons noted above there is a lot of uncertainty as to when and where the storm will make its northward turn.

What should you do?  Well, if you have a hurricane plan just watch the theatrics (and if you live on the coast you’re crazy not to have thought about what you would do, but if you procrastinated again this year look at the FEMA site for some checklists).  Still plenty of time to wait and see, then act if it turns out to really be headed your way.  It will be tomorrow before we have some clarity as to the future path (and even then there will be some fuzziness – there always is – but at least it will be actionable fuzziness).  It is possible some state and local officials will “jump the gun” and start actions this weekend, but if I were them I would be watching, getting things ready in the background, reassuring (not scaring) the public, and getting ready to kick off actions first thing Monday morning.