National Weather Service United States Department of Commerce

Spot Forecasts

 

 

There may be times when a grass or a forest fire is taking place and a Spot Forecast may be necessary. The NWS can do a Spot Forecast for a Federal Agency when a Prescribed Burn or Wild Fire is taking place. A Spot Forecast can be done for a State Commission when they are working with a Federal Agency or a Wild Fire event is occurring.

 

General Spot Information

There are two types of Spot Forecast Products(commonly referred to as "Spots"). The first one is issued to support land management personnel for activities associated with Prescribed Burns. The other is issued to support fire suppression activities of on-going Wild Fires. The main difference between the two is that the format and content of a Spot Forecast for a wildfire is standardized nationally, while the format for the Spot Forecast for a prescribed burn is determined by the local users and will vary from office to office.

Before any Spot Forecast is issued, the requesting agency should provide information about the location, topography, fuel type(s), elevation(s), size, ignition time, and a contact name(s) and telephone number of the responsible land management personnel. Also, representative observations at or near the site of the planned Prescribed Burn or Wild Fire should be available to the responsible WFO prior to the issuance of the Spot Forecast. In the case of a Wild Fire or a prolonged burn, updated observations and information should be provided to the NWS during the course of the event. Spots will be updated whenever they become, or expected to become, unrepresentative of the current forecast.

The general policy of providing Spot Forcasts is established by the local NWS offices and the local customers. The specific contents, issuance frequency, means of communication, and other details of distribution will be determined by local customers and NWS personnel at the time of the customer's request for spot information. 

Critical weather element thresholds for the Spot Forecast will be determined by fire behavior analyst or other fuels/fire behavior expert who will define the range of wind, relative humidity, and any other factors which may cause significant changes to fire behavior. In the case of a Prescribed Burn, these thresholds are often defined in the "Burn Plan", which is normally developed and approved well before a Spot Forecast is requested. In most cases, such information can be obtained from the on-site requester.

Spot Forecasts may be sent to the requester through the mutually agreed upon distribution method. Requesters may communicate via a cell phone. In some cases, Spot Forecasts can be requested through a local "Fire or Emergency Dispatch" system. 

 

Example of a spot forecast for a wildfire

 

FNUS 74 KJAN DDHHMM FWSJAN

SPOT FORECAST FOR (LOCATION OF NAME OF WILDFIRE AND REQUESTING CUSTOMER...ie USFS) ISSUED BY THE NATIONAL WEATHER SERVICE JACKSON, MS TIME-DATE (OCT 4, 2006)

VALID UNTIL <8 HOURS AFTER ISSUANCE>

IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT YOUR NATIONAL WEATHER SERVICE

.HEADLINE...(IF A REDFLAG WARNING/FIRE WEATHER WATCH (JANRFWJAN)) A HEADLINE IS MANDATORY. OTHERWISE A HEADLINE SHOULD BE ADDED AT EVERY ISSUANCE. EX. SPOT FORECAST FOR (NAME OF WILDFIRE)

.DISCUSSION...BRIEF WEATHER SUMMERY AFFECTING FIRE OPERATIONS

.PERIODS (1-3 HOUR INTERVALS FOR TODAY INTO THIS EVENING IF NEEDED INTERVALS FOLLOWED BY AN EXTENDED PERIOD FOR OVERNIGHT AND TOMORROW) or it could be put in a national standard format for three 12 hour periods for today...tonight and tommorrow depending on the customer or IMET.

 

  • THE FOLLOWING CATEGORIES WILL BE INCLUDED:
  • SKY/WEATHER
  • TEMPERATURE
  • HUMIDITY
  • WIND...(20 foot level per recent agreement with fire agencies)
  • OPTIONAL ELEMENTS...SUCH AT STAG INDEX...VENT INDEX...DISPERSION (MIXING HEIGHTS...TRANSPORT WINDS ETC (AS REQUIRED BY OUR AREA CUSTOMERS OR VISITING INCIDENT METEOROLOGISTS...WHICH MAY BE FROM ANOTHER PART OF THE COUNTRY).

 

Spot Forecasts Products for Prescribed Burns

Spot forecasts will be prepared in a format requested by the local customer which can be in graphical or tabular form. In our forecast area we use the tabular format, which may contain any of the following elements as requested by our customers; brief weather discussions, forecast weather, surface winds (including wind shifts), maximum/minimum temperatures and humidity. Upon customer request, other weather elements such as transport winds, mixing heights, stag index, chance of wetting rains. These elements are put into 2-3 hour increments for today through early this evening...depending on customer needs with an extended outlook for overnight and tommorrow. Since Spots are generally for small geographical areas. Areal weather descriptors (such as scattered showers, isolated showers,etc) should not be used. The timing of significant events is important and in the case of wind shifts, extreme critical. Wind forecasts should clearly indicate the level of the wind forecast (i.e. eye level, 20-ft level).

  

FNUS 74 KJAN DDHHMM

FWSJAN

 

SPOT FORECAST FOR 4 MILES NE OF OVETT,MS...USFS

ISSUED BY THE NATIONAL WEATHER SERVICE JACKSON,MS 915 AM JANUARY 9, 2003

VALID UNTIL 515 PM JANUARY 9, 2007

IF CONDITIONS BECOME UNREPRESENTATIVE CONTACT YOUR NATIONAL WEATHER SERVICE

SPOT FORECAST FOR THE TIGER CREEK DRAINAGE PRESCRIBED BURN

DISCUSSION...BRIEF DISCUSSION AFFECTING FIRE OPERATIONS.

TIME...2-3 hour intervals affecting the customer desired time period.

SKY/WEATHER...specifies cloud cover or type of weather expected for the 2 to 3 hour intervals.

TEMP...specifies temps for the 2 to 3 hour intervals.

WINDSPEED (20FT) specifies the surface wind 20 feet above the ground or above tree tops at 1 to 3 hour intervals.

PROBABILITY OF PRECIPITATION...for 1 to 3 hour periods

DISPERSION INDEX for Stagnation Index...Mixing Height...Transport Winds...500 meter Temps etc for 1 to 3 hour intervals.

 

EXTENDED FORECAST (FOR 12-24 HOUR PERIOD) SKY/WEATHER...HIGH/LOW TEMPS...HIGH LOW HUMIDITIES...WINDS...REMARKS.

 

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