As the week between Christmas and New Year's Eve comes to a close, travel across the United States remains in turmoil due to severe storm systems impacting various regions. From coast to coast, messy conditions caused by heavy rain, snow, and flooding are leading to delays both on the roads and in the air.

One storm system, which brought record rainfall to Philadelphia and Atlantic City on Wednesday, is expected to continue its trek up the coast into New England throughout the day on Thursday. The system will bring steady rain and an isolated flooding risk as it moves into the region, with 10 million people under flood alerts as of Thursday morning. Although the rain will mostly taper off by the end of the day, low clouds and lingering showers will continue to disrupt air travel in major hubs such as New York City and Boston. On Friday, rain in Maine is likely to change over to snow, potentially creating hazardous road conditions.

Meanwhile, another storm system is moving across the Florida Peninsula, bringing morning rain to places like Miami and Fort Lauderdale before clearing out by the evening commute. This rainfall poses a risk of delays at Florida airports and may contribute to wet roadways.

In the Midwest, a mix of rain and snow is forecasted to impact the region on Thursday. Although temperatures will remain just above freezing, slushy roads and poor visibility could disrupt travel, especially in the northern sections of Interstates 75 and 65. Flight delays are expected at airports in Chicago, Indianapolis, and Milwaukee as the system progresses eastward. Additionally, the Ohio and Tennessee valleys could experience a few snow showers Thursday night into Friday.

The West Coast is also preparing for heavy rain as another storm system makes its way inland on Thursday and Friday. Cities including Los Angeles, San Francisco, and Seattle are anticipated to experience flight delays. The entire Interstate 5 corridor is likely to see significant rainfall, with totals up to 3 inches possible by Friday afternoon.

As travel conditions continue to worsen across the country due to these storm systems, passengers are advised to stay updated on flight and road conditions, allow for extra time for their journeys, and take necessary precautions to ensure their safety.