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 Equipment Technology Committee Releases Safety Warning: 24-001 Stihl Chainsaw Toolless Fuel Cap Spill Prevention

Date: November 14, 2024
Contact: Equipment Technology Committee

The Equipment Technology Committee (ETC) has released Safety Warning: 24-001 Stihl Chainsaw Toolless Fuel Cap Spill Prevention. Misaligned toolless fuel caps on Stihl chainsaws have led to recurring fuel spillage, fuel ignition, and burn injuries during wildland fire management operations.

This Safety Warning is intended to highlight the details and recommended procedures for the installation of a Stihl chainsaw toolless fuel cap, as well as how to identify and correct a misaligned, damaged, or broken fuel cap to help prevent fuel spillage.

References:

NWCG Safety Warning: 24-001 Stihl Chainsaw Toolless Fuel Cap Spill Prevention

Advertencia de equipos 24-001: Prevención de derrames de la tapa de combustible sin herramientas de la motosierra Stihl

NWCG Alerts

The Incident Position Standards and Next Generation Position Task Book are now available for Equipment Time Recorder (EQTR)

Date: November 13, 2024
Contact: Incident Business Committee

NWCG is excited to announce that the NWCG Incident Position Standards for Equipment Time Recorder, PMS 350-51 and NWCG Position Task Book for Equipment Time Recorder (EQTR), PMS 311-51 are now available.

The Performance Support Package, which for EQTR, includes the Incident Position Standards and Next Generation Position Task Book were developed through the Incident Performance and Training Modernization (IPTM) effort. The Performance Support Package will support trainees, those qualified in the position, and evaluators.

References:

NWCG Equipment Time Recorder Position Page

NWCG Incident Position Standards for Equipment Time Recorder, PMS 350-51

NWCG Position Task Book for Equipment Time Recorder (EQTR), PMS 311-51

The Incident Position Standards and Next Generation Position Task Book are now available for Personnel Time Recorder (PTRC)

Date: November 13, 2024
Contact: Incident Business Committee

NWCG is excited to announce that the NWCG Incident Position Standards for Personnel Time Recorder, PMS 350-53 and NWCG Position Task Book for Personnel Time Recorder (PTRC), PMS 311-53 are now available.

The Performance Support Package, which for PTRC, includes the Incident Position Standards and Next Generation Position Task Book were developed through the Incident Performance and Training Modernization (IPTM) effort. The Performance Support Package will support trainees, those qualified in the position, and evaluators.

References:

NWCG Personnel Time Recorder Position Page

NWCG Incident Position Standards for Personnel Time Recorder, PMS 350-53

NWCG Position Task Book for Personnel Time Recorder (PTRC), PMS 311-53

NWCG Risk Management Committee Releases Safety Bulletin: 24-001 Use of Respirators on Wildland Fires

Date: November 7, 2024
Contact: Risk Management Committee

The Risk Management Committee (RMC) has released Safety Bulletin: 24-001 Use of Respirators on Wildland Fires. As wildland fire respirators are available through several established vendors, wildland fire personnel need to understand regulations and limitations of respirator use in the workplace.

Safety Bulletin 24-001 outlines the following topics regarding respirator use for wildland fires:

  • Requirements for Respirator Use
  • Voluntary Respirator Use
  • Current Respirator Options
  • Unknown Risks of Respirator Use

This bulletin also provides mitigation recommendations to help reduce smoke exposure for wildland firefighting efforts.

References:

NWCG Safety Bulletin: 24-001 Use of Respirators on Wildland Fires

NWCG Smoke Management Guide for Prescribed Fire, PMS 420-3

VIDEO: Protecting Wildfire Personnel from Smoke - How Incident Management Teams Address Smokes Risks

VIDEO: Smoke, Knowing the Risks