Why Hurricane Florence Will Stall or Move Erratically

Jonathan Erdman
Published: September 14, 2018

Hurricane Florence will slow to an agonizing crawl, lashing the Carolinas and parts of the Southeast with prolific rain, storm-surge flooding and destructive winds.

Some hurricanes make landfall, then sweep quickly inland or out to sea. Recent examples of this include Irma in 2017 and Ike in 2008.

Then there are those that stall, meander or move slowly. Harvey in 2017 is the ultimate recent example.

(MORE: Complete Florence Forecast)

Unfortunately, Florence is in that sluggish category.

One Steering Wheel Lost

In the Atlantic Basin, hurricanes are typically steered by the sprawling Bermuda-Azores high, which stretches over vast sections of the Atlantic Ocean.

Florence was being steered toward the coast of the Carolinas by a strong dome of high pressure aloft over the western Atlantic Ocean, off the northeastern U.S. coast.

That strong high-pressure dome, however, has weakened. When that happens, a hurricane loses its steering wheel.

And it slows down.

You can see that in the forecast cone, with very little movement of Florence late this week and early in the weekend.

(MORE: 3 Reasons Slow-Moving Tropical Storms, Hurricanes are the Worst)

Projected Path

New Steering Wheel Installed

Once a new steering wheel in the atmosphere is installed, so to speak, Florence can finally gain some forward speed.

This weekend, another dome of high pressure aloft building over the Midwest and Great Lakes finally begins to shove Florence westward into the Southeast the rest of the weekend.

As that new steering high then shifts off the East Coast, Florence or its remnant will then be pulled around its western edge early next week.

(MORE: Florence Already Has Taken a Weird Track)

The tale of two upper-level highs. The first steered Florence toward the coast. After stalling for a period of a few days, the second upper-level high will finally move Florence along early next week.

All of this is subject to change slightly, so check back for updates.

The upshot of this stall is, unfortunately, long-lived, destructive impacts, including:

- Potentially catastrophic flooding from several feet of rain.
- Life-threatening storm-surge flooding, with water levels remaining high along and near the coast for multiple high-tide cycles in areas of onshore winds.
- Damaging winds, leading to widespread power outages that could last for days.

Florence Rainfall Outlook

Check back with weather.com for updates on Florence's forecast.

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