The latest forecast for Hurricane Joaquin puts it on an unnerving path toward the East Coast, but the track is far from certain right now. This week was going to be a flooding nightmare anyway—the hurricane is just rubbing salt in the wound. You need to prepare now for a significant, potentially life-threatening weather event later this week and this weekend.

It Was Going to Rain Anyway

It’s important to remember that we are going to see a significant rainfall event whether or not Hurricane Joaquin makes landfall in the United States. The hurricane just makes things worse, and even if the storm stays away from land, flooding rains are still likely.

Above is a map of the jet stream from this morning’s run of the GFS (American) model, showing a sharp trough digging through the eastern half of the country. A developing upper-level low will swing around the base of that trough toward the southeast tomorrow and Friday, and the forcing from this—as well as a cold front at the surface—will trigger heavy rain in the Mid-Atlantic and parts of the Northeast.

Most of us from the Carolinas through New England have experienced very heavy rain in the past week. Here in my podunk little part of North Carolina, we’ve seen about a foot of rain since last Thursday, and it’s even worse up in the Virginia mountains. Saturated ground has a hard time accepting and dealing with more water from heavy rain, so it runs off and causes flooding.

Regardless of Hurricane Joaquin’s track, heavy rain is likely in the Mid-Atlantic and Northeast beginning on Thursday and lasting through the weekend. Even a glancing blow from Joaquin will exacerbate the heavy rain, making any flooding even worse.

Here’s the latest precipitation forecast from the Weather Prediction Center showing the combined effects of Joaquin and the rain that would have fallen anyway. It’s not often that you see so much rain covering such a wide swath of real estate. This will create dangerous flooding up and down the East Coast, and in some spots, the floods could be devastating.

These totals will be much higher in spots if Joaquin comes ashore.

Now, about that...

Hurricane Joaquin

The weather models are in an epic tug-of-war right now, and because of this, there is considerable uncertainty in whether or not Hurricane Joaquin will hit the United States or go out to sea. The threat to land is real enough that we need to raise the alarm and get people to prepare, even at the risk of being accused of pushing alarmist hype next week when hindsight is 20/20.

Joaquin quickly strengthened into a hurricane on Tuesday night once wind shear subsided and the storm could organize itself. The 2:00 PM EDT advisory from the National Hurricane Center shows that Joaquin now has 85 MPH winds, and it will probably strengthen into a major hurricane over the next two days as it slowly turns toward the north near the Bahamas.

The National Hurricane Center notes in its discussion that if the track turns out farther west—closer to the East Coast—than forecast, Joaquin will speed up and could make landfall sooner than Monday.

In anticipation of the worst of Joaquin’s winds brushing the island chain, a hurricane warning is in effect for the central Bahamas, and a hurricane watch is up for the northern Bahamas. The storm is slowly drifting toward the southwest this afternoon, but that will change soon once that trough draws close enough to force it to make a sharp northward turn.

What it does after that is critically important to its impacts on the United States. But first, a couple of caveats.

Do Not Focus on the Exact Track

Joaquin will be a large storm if/when it approaches the East Coast, and its effects will extend far away from the center of the storm. Just because the current forecast track has it aiming for New Jersey doesn’t necessarily mean that where it will make landfall, if it does at all. The exact track of the storm will change as models and forecasters get a better handle on the atmosphere and what the storm will do.

Obey the Cone of Uncertainty

The cone of uncertainty is that ghost-like cone that radiates out from the forecast track issued by the National Hurricane Center. The cone of uncertainty is the historical margin of error in their track forecast.

As you get farther out in the forecast period (12, 24, 36, 48, 72, 96, 120 hours), the average error in their forecast grows by several dozen miles each step. By the end of the forecast period—five days out—the center of a tropical cyclone usually winds up within 260 miles their forecast point two-thirds of the time. This means the center of past cyclones strayed off-track even farther than that the other one-third of the time.

The forecast track and cone of uncertainty only apply to the center (eye) of the storm. The effects—wind, rain, surge, waves, etc.—can stretch hundreds of miles away from the center of a storm.

The National Hurricane Center has lower-than-normal confidence in the track Joaquin will take due to the models struggling with the forces at play, so anyone in or around the cone of uncertainty needs to pay close attention to the storm.

Stuck Between a Rock and a Hard Place

Predicting where Joaquin will go is tricky because there are so many different factors at play that any one could dramatically alter its ultimate path, let alone the effect when they all work together.

The above image is from this morning’s run of the GFS model showing us what it thinks the mid-levels of the atmosphere will look like around 2:00 AM EDT on Friday morning. Blue indicates lower heights (essentially, lower pressure), while oranges and reds indicate higher heights (higher pressure).

You can see Joaquin hanging out down near the Bahamas while the upper-level trough/low approaches from the west, and a ridge of high pressure and the remnants of Tropical Storm Ida sit over the ocean to the east. The GFS is one of the models that sends Joaquin careening into the East Coast—in this scenario, the trough lifts Joaquin to the north, and it gets caught against the high, and with nowhere else to go, it turns west and slams into the Mid-Atlantic.

This interaction between the trough, the hurricane, and the ridge/ex-Ida will determine what happens. It’s worth noting that some models—namely the European model—shows the trough kicking Joaquin out to sea like a kickball. The Euro has a stellar track record, especially when it comes to hurricanes, so a big reason for the uncertainty is that the Euro is showing such a dramatically different solution than many of the other big models.

However, when you look at the spaghetti plots (above), it would be irresponsible to hug the Euro (despite its track record) and ignore everything else pointing Joaquin toward the East Coast. Spaghetti plots show a tropical cyclone’s possible track based on numerous runs of numerous models. When the lines are tightly packed together, there’s strong consensus, and when they wildly diverge like a party popper, there’s not much agreement.

The normally-trusty Euro diverging wildly from these solutions is why we’re so uncertain about where Joaquin will wind up.

The National Weather Service has ordered weather balloon launches every six hours (instead of the normal interval of twelve), in addition to hurricane hunter flights flying into the storm and upper-air reconnaissance by Gulfstream jets flying through the atmosphere around the hurricane. This extra data should help the models figure out what Joaquin will do. By late tonight and early tomorrow, we’ll know much more than we do right now.

Prepare, Prepare, Prepare

All year, we’ve said that El Niño would cause this Atlantic hurricane season to be quieter than normal, and as expected, we’ve seen one storm after the other bubble up and immediately shred apart in the incredible wind shear tearing across the ocean basin.

We’ve constantly qualified that statement with “it only takes one,” one storm sneaking through and taking advantage of the rare occasion when all the ingredients come together to allow a big storm to develop and threaten land.

This is that exact scenario.

You need to be proactive about your safety. If you haven’t done so, you need to quickly prepare for the potential of a widespread heavy rain and strong wind event that could possibly cripple areas for a week or longer. We won’t know exact impacts until forecasters and models are reasonably sure where Joaquin will make landfall, if it does so at all.

Hopefully this is all for naught. There is a chance of that. However, we don’t know that yet, so we have to get ready regardless. Here are some things you need to keep in mind as you get ready for whatever is going to happen later this week and this weekend.

  • With already-saturated ground, it won’t take much wind to knock down trees and power lines. Make sure you have enough non-perishable food and bottled water to last everyone in your household a week or longer. Canned food like ravioli, peanut butter and jelly, bread, durable fruit (for example, fresh, whole apples hold up well), stuff like that.
  • Just before the worst of the storm, fill up your bathtubs and sinks with water. You’ll need this water to pour in your toilet tank to flush if water service goes out.
  • You’ll need plenty of batteries to power flashlights and radios. Candles work for lighting, too, but you need to watch them like a hawk. The only thing worse than a bad storm is your house burning down during a bad storm.
  • Think about your cell phones—portable chargers or car chargers are a must. Make sure you have another way to communicate (and old flip phone or landline) in case something happens to your cell phone. If you have an old cell phone lying around, they can still dial 911 even if they’re not connected to a paid service anymore.
  • Keep your car as full of gas as possible and make sure the battery isn’t on its last gasps. If your power goes out, your car will serve as your giant, expensive phone charger, if nothing else.
  • Keep some cash on hand. If the power, telephone, and/or internet go down, you won’t be able to use debit or credit cards.
  • Make sure you have prescription medicine to last you a week or longer.
  • Prepare a first aid kit complete with stuff like bandages, peroxide, antibacterial cream, pain medication, and stuff to calm down an upset stomach.
  • Make sure you have enough personal hygiene products—stuff like toilet paper, deodorant, pads and tampons, toothpaste, and all that. Don’t forget hand sanitizer and baby wipes in case the water goes out. Keeping your hands clean could prevent a nasty illness.
  • Photograph and document valuable belongings in case they’re damaged or lost during the storm. It’ll help for insurance purposes, if not just to look back and remember them one day.
  • Keep important documents (social security cards, birth/death/marriage/divorce/immigration/deed papers, diplomas, business documents you’re hiding from the government, etc.) in a watertight, safe location. Put them in one waterproof container after the other if possible.

If you live in an evacuation zone, have a plan in case you’re told to evacuate. If you’re told to evacuate, do your best to leave. You are on your own during the worst of a storm—rescue crews won’t go out until conditions are safe enough for them to do so.

Scope out flood-prone roads on your daily route before the rain starts, and stay home as often as possible during bouts of heavy rain. Do not drive through a flooded roadway. It is very hard to judge the depth of floodwaters—no matter how good you think you are, you will likely underestimate it.

The majority of flood deaths in the United States occur in vehicles after people tried to drive across a water-covered roadway. It only takes a foot of moving water to lift a car and sweep it away. Do not risk your life or the lives of your rescuers because you refused to turn around. Nothing on the other side of a flood is worth risking your life or the lives of those around you.

This whole event has the makings of something we could remember for years, but it could just as easily turn into a whole lot of nothing and we forget about it in a few weeks. Hope for the best, but do everything in your power to prepare right now so we don’t ask “where did we go wrong?” when the skies clear out next week.

You can follow the latest advisories on Hurricane Joaquin at the National Hurricane Center’s website, and you can find updated forecasts—including detailed rainfall and wind forecasts—for your location by visiting your local National Weather Service office’s website. And, as always, I’ll provide updates here on The Vane and even more frequently over on Twitter.

[Satellite Images: NOAA | Models: Tropical Tidbits | Hurricane/Rain Maps: author]

Email: dennis.mersereau@gawker.com | Twitter: @wxdam

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