It's going to be a hot holiday in the Florida Panhandle as high pressure locks in the summer heat.
FORT WALTON BEACH — A typical summertime weather pattern is projected to bring very high temperatures to the Florida Panhandle throughout this week and into Monday, creating the possibility that a heat advisory will be issued by the National Weather Service for at least part of the Fourth of July holiday weekend.
Heat advisories are issued when the heat index — the combined effects of heat and humidity as felt by the average person — is expected to reach somewhere between 105 degrees and 109 degrees. Advisories are issued between 12 and 24 hours before the heat index threshold is reached, and serve as reminders for people to stay hydrated, wear light-colored clothing, and ensure that children or pets are not left alone in vehicles.
""It's going to remain hot throughout the whole period," Don Shepherd, a meteorologist with the National Weather Service forecast office in Mobile, said Monday morning. "Each day through this week, we're looking at progressively hotter temperatures as well as the heat index."
Daytime high temperatures will, for the most part, be in the low to mid-90s through next Monday, he said, while the heat index will be at least 100 degrees throughout that time. The more moisture there is in the air, the higher the heat index will be, Shepherd explained.
Currently, temperatures and the heat index in the western Florida panhandle are expected to be at their peak on Thursday, which is the Fourth of July holiday, and on Friday, according to Shepherd. With regard to issuing a heat advisory, Shepherd said, "we're going to be flirting with that as we come up on Thursday and Friday."
According to Shepherd, the heat index is likely to be in the 106-degree to 108-degree range on Thursday, with some areas possibly seeing a heat index of 109 degrees to 110 degrees. A heat advisory will be issued when the heat index is expected to be at 108 degrees across a wide area of the western Florida panhandle, Shepherd explained.
Even with the expected high temperatures and heat index, this week "looks pretty much like a typical summertime pattern," said Shepherd.
The heat that will be felt across the area is the result of a high pressure system that will be centered directly over the area until early next week, combined with a high sun angle, Shepherd explained. Routinely, Shepherd said, high pressure systems affecting this area are located to the east, which brings offshore winds from the Gulf of Mexico over the coastline to help moderate temperatures in the evening. With the high pressure system centered over the area, those onshore winds are weakened, Shepherd explained.
The winds that do make it ashore this week will combine with moisture in the air to produce whatever afternoon and evening showers will develop, Shepherd added, producing some localized cooling.
The National Weather Service's Tallahassee forecast office, which covers Walton County and extends eastward, largely mirrors the Mobile office forecast. A Monday forecast discussion on the Tallahassee NWS website indicated that "(h)eat index values are expected to remain near the heat advisory criteria of 108 (degrees) through the 4th of July across the Florida panhandle ... . High temperatures will likely drop a few degrees back into the low to mid 90s by Friday into the weekend with slightly lower heat index values in the upper 90s to lower 100s."
As the times for area fireworks displays approach Thursday, temperatures will be dropping from daytime highs in or near the 90s to nighttime lows in the 70s, with the chance of thunderstorms moving from 50 percent during the day to 20 percent overnight, according to NWS forecasts.
Interestingly, area beaches will provide some limited relief from the heat throughout the week, because they will get whatever onshore breezes are produced by the high pressure system. But, Shepherd said, any relief available on the beaches will not be particularly significant.
"If anywhere is going to feel a little bit better, it's going to be the beach areas," he said. "If you're lucky enough to be near on of those, it might cool you off a little bit, but the heat index will still be 100 degrees."