Skip to main content

PMS 425

PMS 425

PMS 425

NWCG Guide to Fire Weather Forecasts PMS 425

1. Introduction

2. Fire Weather Forecast Variables

3. Types of Fire Weather Forecasts

4. Building a Mental Model of the Weather Forecast

1. Introduction

Fire weather forecasts are likely one of the first professional introductions firefighters have to meteorological information. They may even be the first thing a firefighter reads each day when they get to their duty station. Forecasts convey certain atmospheric variables. The intent of this guide is to describe best-practices on how to interpret and use the weather information provided.

Fire weather forecasts include several components:

  • Header information
    • Date and time the forecast is valid for
    • Applicable forecast headline
  • Forecast discussion
  • Mandatory forecast elements of sky/weather
    • Temperature
    • Relative humidity (RH)
    • Wind
  • Optional forecast elements that may include the chance of:
    • Wetting rain
    • Mixing height
    • Transport wind
    • Smoke dispersal
    • Inversion information
    • Haines Index
    • Lightning activity level (LAL)
    • Extended forecast or outlook

Each forecast element is generally given only one value per operational period.

The weather forecast is a static document that may not adequately describe the changes one sees in the weather through an operational period. For example, fire weather forecasts only provide the high temperature for day operational periods and the low temperature for night operational periods. It is left up to the firefighter to interpret how fast and when the temperature will rise and/or fall during their shift. Consistent weather is a firefighter’s friend. It is the change in weather conditions that prove problematic and sometimes fatal to operational resources. This publication provides context and interpretation guidelines for fire managers and fireline personnel to make improved decisions with safety in mind.

There are links to online resources throughout this publication. Visit these resources, as additional information and graphics are often provided. The most frequently linked resource is the Agriculture Handbook 360: Fire Weather… A Guide for Application of Meteorological Information to Forest Fire Control Operations, PMS 425-1. Refer back to it as you learn more about fire weather forecasts.

Modified / Reviewed:

Print PDF

NWCG Latest Announcements

NWCG Standards for Wildland Fire Chainsaw Operations, PMS 212, and Next Generation Position Task Book for Basic Faller Are Now Available

Date: April 14, 2025
Questions?  Please contact:
Hazard Tree and Tree Felling Subcommittee

The updated NWCG Standards for Wildland Fire Chainsaw Operations, PMS 212, and NWCG Position Task Book for Basic Faller (FAL3), PMS 311-19 are now available.

The NWCG Standards for Wildland Fire Chainsaw Operations, PMS 212 includes position standards designed to be used in conjunction with the Next Generation Position Task Book (Next Gen PTB). The Next Gen PTB for Basic Faller (FAL3) includes an evaluation guide with suggested rating elements to consider when assessing trainees.

References:

NWCG Standards For Wildland Fire Chainsaw Operations, PMS 212

NWCG Position Task Book for Basic Faller (FAL3), PMS 311-119

NWCG Basic Faller (FAL3)

RMC Memo 25-01: Summary of Updates to Safety Officer Positions

Date: April 9, 2025
Questions?  Please contact:
RMC Member Eric Fransted

The Risk Management Committee (RMC) serves as the position steward for all Safety Officer incident positions and continues to improve position standards, training, and naming conventions. The implementation of Complex Incident Management (CIM) required changes to position titles. RMC collaborated with the NWCG Incident Position Standards Committee (IPSC) to propose and implement these updates. 

References:

RMC Memo 25-01: Summary of Updates to Safety Officer Positions 

NWCG Position Catalog

Updated, NWCG Guide to Wildland Fire Origin and Cause Determination, PMS 412

Date: April 8, 2025
Questions?  Please contact:
Wildland Fire Investigation Subcommittee

PMS 412 provides guidance for wildland fire investigations. This guide outlines recommended procedures, practices, techniques, and methods to promote a systematic approach. The last update to this publication was in 2016.

References:

NWCG Guide to Wildland Fire Origin and Cause Determination PMS 412

Updated NWCG Standards for Airtanker Base Operations, PMS 508

Date: March 31, 2025
Questions?  Please contact:
Airtanker Base Operations Unit

The updated NWCG Standards for Airtanker Base Operations (SABO), PMS 508 standardizes operations and procedures at interagency airtanker bases to ensure safe, efficient, and effective operations in support of interagency goals and objectives.

References:

NWCG Standards for Airtanker Base Operations, PMS 508