Active weather on Wednesday ahead of Helene

Wednesday:

A trough of low pressure pushes into the southeast on Wednesday as high pressure that has dominated the region slides eastward into the western Atlantic. Winds will shift accordingly to a more southerly direction, bringing a much more humid air mass that is being pushed into the Gulf of Mexico ahead of Tropical Storm Helene. This added moisture and uplift due to the approaching trough will allow for showers and thunderstorms that begin in the early morning hours in the western Panhandle before spreading generally eastward as we move into the afternoon.

There is a risk of severe weather throughout the day, with isolated damaging winds, heavy rain, and even a tornado or two possible as storms move through the area. The Storm Prediction Center has placed the Florida Panhandle and Big Bend regions under a Marginal Risk (level 1 of 5) of severe weather for Wednesday. This active weather situation during the day means preparations for Helene should be completed as soon as possible, despite direct impacts not arriving until the evening. By 8 p.m., the outer bands of Helene will start to reach northern Florida, bringing more widespread rain and storms to the region.

Thursday:

As of 11 p.m. Tuesday, Tropical Storm Helene is located over the northwest Caribbean Sea, and has sustained winds of 60 mph. The exact intensity of Helene at landfall will depend largely on how much the inner core of the storm develops on Wednesday as it moves through the Yucatan Channel. If Helene is able to avoid significant interaction with both the Yucatan Peninsula and the western tip of Cuba, it will likely be able to strengthen significantly over the next 24 to 48 hours thanks to a favorable atmospheric environment featuring low wind shear and very warm ocean temperatures. The National Hurricane Center currently predicts that Helene will be a Category 3 hurricane with sustained winds of 120 mph when it makes landfall in Florida's Big Bend. As such, a Hurricane Warning is currently in effect along the coast from Pasco County northward through Bay County, including areas as far inland as the Florida-Georgia border.

Strong southerly flow between the aforementioned high pressure to the east and the upper-level trough moving into the Mississippi River Valley will pull Helene quickly northward through the Gulf of Mexico on Thursday. Models have been remarkably consistent in showing this solution over the past few days, though there is still some uncertainty in where exactly Helene will make landfall. Regardless, conditions will begin to significantly deteriorate by around midday Thursday, with rain, wind, and storm surge quickly worsening throughout the region as Helene moves rapidly northward.

Helene is forecast to be a very large hurricane, so tropical storm and hurricane conditions will extend very far from its center. This will also contribute to a significant storm surge threat, and a Storm Surge Warning is in effect along the entire west coast of the Florida Peninsula and the Big Bend. The worst storm surge is expected from the Ochlockonee River east to Citrus County, where upwards of 12 feet of storm surge is possible.

Further inland, rain and wind are the primary hazards. Helene's fast forward motion means its highest wind speeds will penetrate further inland than might otherwise be expected. Significant wind damage is likely, especially along the coast, but also for areas well inland, as Helene is still expected to be a strong tropical storm as it moves through Georgia. Rainfall will also pose a significant hazard, contributing to localized inland flooding. Widespread power outages are very likely during the storm and in the aftermath. If you are not evacuating, be prepared to spend multiple days without power.

Friday:

Helene's rapid forward motion means its worst impacts will be over by midday Friday, and typical September weather will return as dry air moves in behind the storm. High temperatures will be in the low to mid-80s, and rain chances will be low once Helene moves far enough north. These conditions are likely to continue into the weekend, allowing for relatively comfortable weather amidst storm cleanup.

Forecaster: Peter Etz