Fire Weather Watch and Red Flag Warning Criteria

Red Flag Warnings and Fire Weather Watches

The National Weather Service (NWS) issues Red Flag Warnings and Fire Weather Watches to alert land management agencies about the onset, or possible onset, of critical weather and fuel moisture conditions that could lead to rapid or dramatic increases in wildfire activity. This could be due to low relative humidity, strong winds, dry fuels, or any combination thereof. Each year, the NWS coordinates with each state to implement a State Annual Operating Plan related to fire weather services. Red flag criteria are set in these plans and vary from state to state. NWS Tallahassee serves portions of three states, each with their own red flag criteria. These criteria are summarized in the table below.

Red Flag Warning Criteria

State	RH	RH Duration	Winds	KBDI*	ERC**	Fuel Moisture(10-hr)
Georgia	≤ 25%	1 hr	≥ 15mph OR frequent gusts ≥ 25mph	-	-	≤ 6%
Alabama	< 25%	4 hr	≥ 15mph	≥ 300 OR AL Fire Alert	-	-
Florida	< 28%	-	≥ 15mph	-	≥ 26	-

*KBDI - Keetch-Byrum Drought Index
**ERC - Energy Release Component

A Red Flag Warning is issued when the above conditions are expected to be met within the next 24 hours. A Fire Weather Watch is issued when the above conditions are expected to be met during the next 24 to 48 hours. Typically, these watches and warnings are issued at the same time the routine fire weather forecasts are issued, approximately 3:30 AM and 3:30 PM Local Time.

A glossary of fire weather terms is provided here for your reference.