Jacksonville is facing drastic weather conditions this week, with both critical fire danger and a blast of Arctic cold impacting locals.
A red flag warning is in effect from 1 to 6 p.m Monday as gusty northwesterly winds and critically low humidity levels combine to create dangerous fire weather conditions across North Central Florida and parts of Northeast Florida. The dry, breezy pattern significantly increases the risk of rapidly spreading wildfires.
At the same time, freeze warnings have been issued area-wide from midnight Monday through 9 a.m. Tuesday as Arctic air pushes deeper into the region Monday night. A hard freeze is expected across inland Southeast Georgia, the Suwannee Valley, and portions of inland Northeast Florida west of I-95, including areas around Jacksonville. Temperatures are forecast to plunge into the 20s and low 30s by daybreak Tuesday.
Here’s what to know about the red flag warning and the incoming freeze, how long the cold will last, and just how low temperatures are expected to drop.
What’s a red flag warning?
A red flag warning is issued to alert fire managers on federal lands that weather and fuel conditions are especially dangerous for fire activity. When a red flag warning is in effect, planned burns are usually postponed because any fire that starts could spread quickly and become difficult to control.
Red flag warning in effect Monday, Feb. 23, from 1 to 6 p.m.
All of North Central Florida and portions of Northeast Florida are under a red flag warning on Monday. Strong northwest winds of 15 to 20 mph, ongoing extreme drought conditions, and minimum relative humidity values near 25 percent have created critical fire weather conditions.
The red flag warning is in effect from 1 p.m. until 6 p.m. this evening.
What areas are affected by red flag warning?
The National Weather Service has issued a red flag warning for 33 of Florida’s 67 counties, including all of North Central Florida and portions of Northeast Florida.
The warnings follow drought conditions that continue to worsen in the state.
When is a red warning issued?
According to the National Weather Service, three main factors must come together for a red flag warning to be issued:
1. Very dry small fuels (10-hour fuels at 8% moisture or less)“Ten-hour fuels” are small materials like grass, leaves, pine needles, and mulch. They are called 10-hour fuels because they respond to changes in moisture in about ten hours. When their moisture content drops to 8% or lower, they can ignite easily and burn rapidly.
2. Very low relative humidity (below 25% for several hours)Relative humidity (RH) measures how much moisture is in the air compared to how much it could hold at that temperature. When RH is low, the air pulls moisture out of vegetation, making fuels even drier and more flammable.
3. Strong, sustained winds (at least 15 mph at 20 feet above the ground for several hours)Wind supplies oxygen to a fire, pushes flames into unburned fuels, and can carry embers ahead of the main fire. Sustained winds of 15 mph or more significantly increase the risk of rapid fire spread.
When all three of these conditions occur together — very dry fuels, dry air, and strong winds — the potential for extreme and fast-moving wildfire growth becomes much higher.
Fire risks increase under red flag warning
The combination of conditions as mentioned above “results in an increased risk for a wildland fire or rapid-fire growth if an incident were to occur,” according to the International Association of Fire Chiefs.
Red flag warning safety tips
Here’s what you can do to reduce the chance for wildfires while under a red flag warning, according to IFAC.org:
Freeze warnings and cold weather advisories are in effect Monday night through Tuesday morning. How low will temperatures drop?
Cold weather advisories are in effect for all of Northeast and North Central Florida, with a freeze watch in place from 2 to 9 a.m Tuesday. Overnight lows are expected to drop into the 23 to 32 degree range, with widespread freezing conditions likely. Freeze warnings have also been issued area-wide from midnight through 9 a.m. Tuesday.
Doris Alvarez is a Breaking and Trending Reporter for The Florida Times-Union. You can get all of Jacksonville’s best content directly in your inbox each weekday by signing up for the free Daily Briefing and News Alerts newsletters at jacksonville.com/newsletters.
This article originally appeared on Florida Times-Union: Red flag warning, freeze warning issued for Jacksonville. What to know
Reporting by Doris Alvarez Cea and Cheryl McCloud, Jacksonville Florida Times-Union / Florida Times-Union
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