Services Provided by the National Weather
Service
Routine Fire Weather Planning Forecasts (FWF)
Issuance
Routine Fire Weather Planning Forecasts are issued twice a day, by
0700 LT in the morning, and preferably by 1500 LT in the afternoon
(no later than 1600L), every day of the year. Updates will be done
as conditions warrant, and also generally at 11 AM, however, at night,
updates will not be done when land managers are not on duty to utilize
these forecasts.
How Forecast is Issued and Accessed
Forecasts will be issued from the Advanced Weather Interactive Processing
System (AWIPS) at each NWS office, and sent over to the internet web
page of the respective office. Customers may then access the forecast
from the appropriate web page. In the event of an internet outage,
the customers may call the NWS offices and have the forecast faxed
to them. Customers will look for the routine 11 AM update on the internet.
NWS WFO's will notify customers of non-routine updates.
Content of the Forecast
The format of the Fire Weather Forecast is specified in National
Weather Service Directive 10-401. The forecast will start with a
headline of Red Flag Warnings or Fire Weather Watches
(or of meteorological trends), followed by a meteorological discussion.
The forecast will then be broken down by zone groupings of counties
expecting similar weather in the early forecast period (days one
and two).
The morning forecast will include three periods; today, tonight,
and tomorrow. The afternoon forecast will include four periods;
tonight, tomorrow, tomorrow night, and the next day.
Fire Weather Forecast (FWF) Parameter Definitions
CLOUD COVER or CLOUD AMOUNT: Represents the average sky condition over the specified area during the specified period. For example, “Clear” or “Sunny” indicates cloud cover < 10%; “Mostly Clear” or “Mostly Sunny” are used when cloud cover is ≥10% and <30%; “Partly Cloudy” or “Partly Sunny” are used when cloud cover is ≥30% and <60%; “Mostly Cloudy” is used when cloud cover is ≥60% and <80%; and “Cloudy” is used when cloud cover is ≥80%.
CHANCE PRECIP: Represents the chance (rounded to the nearest 10%) of measurable (≥ 0.01 inches) precipitation over the specified area during the specified period. Note: Drizzle and snow flurries are not considered measurable precipitation and thus will not be given a probability.
PRECIP TYPE: Represents the predominant precipitation type over the specified area during the specified period. Note: The only exception is when showers and thunderstorms are expected, as only thunderstorms will be designated as the precipitation type.
MAX/MIN TEMP: Represents the expected maximum (during the daytime period) and minimum (during the nighttime period) temperatures over the specified area.
MAX/MIN RH: Represents the expected maximum (during the nighttime period) and minimum (during the daytime period) relative humidity (%) over the specified area.
WND20FT2MIN/EARLY and WND20FT2MIN/LATE: Represents the 2-minute average wind speed (MPH) and direction 20 feet above the ground or vegetative cover. Wind direction is the direction the wind blows from. “Early” refers to the morning hours (before noon) during daytime period and also the evening hours (before midnight) during nighttime periods. “Late” refers to the afternoon hours during the daytime period and the pre-dawn (after midnight) hours during the nighttime period. Wind gusts, which are rapid fluctuations in wind speed of usually less than 30 seconds in duration, are indicated if expected. The highest probable wind gust will be preceded by a “G” and will usually only be included if they are 10 MPH or greater than the sustained wind speed.
PRECIP AMOUNT: Represents the precipitation amount (hundredths of an inch) whenever the chance of precipitation is ≥20%.
PRECIP DURATION: Represents the duration of measurable precipitation (hours) when the chance of precipitation is ≥20%.
PRECIP BEGIN: Represents the begin time (to the nearest hour) of measurable precipitation when the chance of precipitation is ≥20%.
NOTE: Only used by WFO CAE and WFO CHS.
PRECIP END: Represents the end time (to the nearest hour) of measurable precipitation when the chance of precipitation is ≥20%.
NOTE: Only used by WFO CAE and WFO CHS.
LAL: Represents the Lightning Activity Level, as defined below.
1: No thunderstorms.
2: Cumulus clouds are common, but only a few reach towering cumulus stage. A single thunderstorm must be confirmed in the rating area. The clouds mostly produce virga, but light rain will occasionally reach the ground.
3: Cumulus clouds are common. Swelling and towering cumulus cover less than 2/10 of the sky. Thunderstorms are few, but two or three must occur in the observation area. Light to moderate rain will reach the ground and lightning is infrequent.
4: Swelling cumulus and towering cumulus cover 2/10-3/10 of the sky. Thunderstorms are scattered, but more than 3 must occur in the observation area. Moderate rain is commonly produced and lightning is frequent.
5: Towering cumulus and thunderstorms are numerous covering more than 3/10 of the sky and occasionally obscure it. Rain is moderate to heavy and lightning is frequent and intense.
6: Same as #3, but dry (little to no rain reaching the ground).
HAINES INDEX: Represents the Haines Index, which is used to describe the stability of the atmosphere, with values ranging from 2 to 6. In the South Carolina Coastal Plain, Piedmont, and Foothills, "low elevation" is assumed for the calculation of the Haines Index. It utilizes the atmospheric temperature at 950 mb and 850 mb as well as taking into account the moisture levels (dew point depression) at 850 mb. In the South Carolina mountains, the "mid level" Haines Index is calculated using the temperatures at 850 and 700 mb, and the dew point depression at 850 mb.
DSI: Represents the Davis Stability Index, which is the maximum surface temperature (in deg C) minus the 850 mb temperature (in deg C). If the difference is <10 deg C, it is considered a Category 1 (stable); between 10 deg C and 14 deg C, it is considered a Category 2 (conditionally unstable); between 15 deg C and 17 deg C, it is considered a Category 3 (unstable); and >17 deg C, it is considered a Category 4 (absolutely unstable). Note: DSI is only computed for the daytime period.
MIXING HGT: Represents the mixing height, or the height (in feet above the ground) to which vigorous vertical mixing takes place.
DISPERSION: Represents the begin and end times of the low-level (usually surface-based) inversion as well as the category of dispersion during this period based on the surface wind speed. The dispersion category gives a general indication of the state of the atmosphere with respect to its ability to disperse smoke. The categories are as follows: Very Poor (VP) or Poor (PO): 0-4 MPH winds, Fair (FA): 5-7 MPH winds, Good (GD): 8-9 MPH winds, Excellent (EX): ≥10 MPH winds. It is assumed that at least fair mixing is occurring in the evening prior to the onset of the nighttime inversion.
NOTE: Only used by WFO CAE and WFO CHS.
INVERSION: Represents the temperature and time at which the morning inversion will burn off as well as the time it will set up in the evening. If the inversion is not surface-based (yet still at low levels, e.g. below 1000 ft), meteorological factors other than nighttime radiational cooling may be taking place and as such, inversion information may not be given ("Inversion" remains in the forecast through the day, which would be reflected by a low mixing height). Conversely, there will be situations when a low-level inversion does not develop at night and thus "NONE" will be noted. Other inversion notation includes CONT (for continued inversion), and MIXED/HHMM (when an inversion mixes out at local time HHMM.
NOTE: Used by WFO's CHS and GSP.
TRANSPORT WND: Represents the transport wind, or the average wind direction and speed (MPH) from the surface to the top of the mixed layer (mixing height). Direction indicates where the wind is blowing from.
VENT RATE: Represents the ventilation rate (FT MPH), or the potential for the atmosphere to disperse smoke. It is computed by multiplying the mixing height by the transport wind. Ventilation rates are used to determine Burn Categories.
Offices serving counties in North Carolina (GSP and ILM) may also
include a wind profile
analysis (March through May), but will not include dispersion or burn category,
since the values defining these elements differ from North Carolina to South Carolina.
At the bottom of the forecast for each forecast
area (zone grouping), an extended forecast for days three
through seven will be appended. This will be include a forecast of
winds and minimum relative humidity.
Updating the Fire Weather Planning Forecast
The Fire Weather Forecaster will maintain a weather watch to ensure
that the forecast remains accurate. When unexpected changes occur
or are forecast to occur which significantly deviate form the previous
forecast, the forecast will be updated. The decision to update, to
an extent, is at forecaster discretion. The update criteria for various
elements are listed below. It is a shared responsibility
for the WFO's and the natural resource agencies to monitor the need
to update a forecast. Respective agency personnel will also provide
feedback as to the updating of an FWF, NFDRS Point, or Spot Forecast.
Interim FWF Update Criteria
Standard Air Temperature: +/- 5 degrees F.
Relative Humidity: +/- 5%.
Wind Speed and Direction at 20 ft AGL: +/- 5 mph and/or 45 degrees.
Precipitation POP, duration and amount: same as for public zones.
Note: duration guideline for NFDRS is +/- 2 hours.
Inversions: +/- 100 m or 328 ft.
Freezing Level: +/- 100 m or 328 ft.
Transports Winds: +/- 5 mph and/or 45 degrees.
Mixing Height: +/- 100 m or 328 ft.
Stability: Must be in correct category 90% of time.
Burn Category: One category of change.
Dispersion: One category of change.
Note: Morning upper air soundings from nearby weather balloon sites
should be examined for update criteria.
(TOP)
Site Specific Wildland Fire Forecasts (Spot Forecasts) (FWS)
Criteria
Spot forecasts will be issued on request to any government agency
for a wildfire. Requests for spot forecasts for non-wildfire purposes
will only be honored from federal agencies, from non-federal government
agencies operating within the bounds of an interagency agreement with
the federal government, or from any non-federal government agency
when public safety is at risk. Spot forecasts will typically cover
three 12 hour periods (example: Today, Tonight, Tomorrow), but may
cover fewer or more periods as the customer requests. Any forecast
beyond day two will typically be an outlook.
Contents
The format of the Spot Forecast is specified in National Weather Service
Directive 10-401. A spot forecast will be headlined for Red
Flag Warnings or Fire Weather Watches. The forecast will
then begin with a meteorological discussion, and will include any
of the following information as designated by the requesting customer:
temperature, relative humidity, wind direction and speed (20 ft, 2min),
cloud cover, weather phenomena, probability of precipitation, type
of precipitation, mixing height, and transport wind. Additional elements
such as inversion setup time, Haines Index, or Lightning Activity
Level may be requested by the customer.
There are essentially two formats available for the spot forecast: (1) narrative and (2) tabular. The narrative format gives a general format usually in 12-hour blocks out to around 36 hours. The tabular format can provide detailed information on the individual parameters in 1, 2, or 3 hour increments. However, because of a nationwide agreement between the NWS and various state and federal forestry agencies, the narrative format must be used to satisfy spot forecast requests for wildfires.
Procedures
The requesting customer should go to the local NWS office internet
home page, seek the fire weather web page, then select the procedure
for requesting a spot forecast. The spot forecast request page is
nationally standardized, and prompts the customer for information
about the location, elevation, and size of the fire, as well as
for observations and contact phone numbers. The location of the
fire will then appear on a topographic map image, allowing both
the requesting customer and the NWS forecaster to see its location.
The customer may customize their request by highlighting which elements
they need, and for which forecast periods. A remarks section allows
the customer to ask for additional elements and or time period.
In case of an internet outage, the customer may fax in a request,
using form D-1. A call to the NWS office to alert them to the spot
request is recommended.
Customers are reminded to provide as fresh an observation as possible.
Requests made the night before a burn should be viewed as outlook
forecasts, and a fresh forecast should be requested in the morning
with a new observation.
The spot forecast will usually be issued within thirty minutes
of a request, depending on current weather, and volume of spot forecasts.
The completed spot forecast will be sent out over the internet,
and will be available on the same web site the customer used to
request the forecast. (TOP)
National Fire Danger Rating System (NFDRS) Forecasts (FWM)
Issuance
NFDRS forecasts will be issued for any predetermined site from which
an NFDRS observation is received, provided the observation is received
on time, is complete, and is deemed accurate. The land management
agencies will determine which observation sites (normally RAWS sites)
will be NFDRS sites. Initiation of NFDRS forecasts for a new site
will be coordinated with the NWS, and the agency requesting new NFDRS
service will provide the NWS with information about the site location.
Contents
The format of the NFDRS Forecast is specified in National Weather
Service Directive 10-401. The NFDRS forecast will be a forecast of
the next day observation at 1300 LST. The forecast will include expected
state of weather, temperature, relative humidity, wind speed and direction
( to 16 points) at 1300 LST. The forecast also includes the expected
lightning activity level for the next day and a half, the 24 hour
maximum and minimum temperature and relative humidity, the 24 hour
precipitation duration, and whether fuels will be wet (wet flag) at
1300 LST.
Procedures
The land management agencies are responsible for taking, quality
controlling, transmitting and archiving the NFDRS observations.
Observation must be received at the NWS in a timely manner. Forecasts
will only be prepared for predetermined sites, and only from those
sites for which an observation has been received. The NWS will prepare
and transmit the NFDRS forecasts no later than 4 PM. Although the
data cutoff time for ingest into the NFDRS software is 7 PM, preliminary
calculations based on the forecast are used by the land managers to make
staffing decisions at shift briefing time (4 PM).
(TOP)
Fire Weather Watch and Red Flag Program (RFW)
Criteria
A Red Flag event is defined as a combination of high (or greater)
fire danger and critical weather elements. For South Carolina, the
two or more of the following weather criteria must be occurring
or expected, in addition to high (or greater) fire danger. Wind
criteria are for 10 meter, 2 minute average wind. A 10% reduction
must be applied to the criteria when comparing against the FWF wind,
which is a 20 ft 2 minute average wind.
Relative Humidity of 25% or less.
Sustained wind of 20 mph or greater, or gusts to 30 mph or greater.
Dry lightning.
A significant wind shift during times of active fire suppression.
Fire danger will be assessed by the land management agencies, and
will be obtained from them by the National Weather Service.
If Red Flag criteria are occurring, or expected within 24 hours,
a Red Flag Warning will be issued, and will remain in effect until
the conditions abate or are no longer expected.
If Red Flag criteria are expected within 12 to 72 hours, a Fire
Weather Watch will be issued, and will remain in effect until the
watch is upgraded to a Red Flag Warning, or conditions are no longer
expected to develop.
Contents
The format of the Red Flag Warning and Fire Weather Watch is specified
in National Weather Service Directive 10-401. A Red Flag Warning or
Fire Weather Watch will begin with a headline stating which product
is in effect, the area the product covers, and the meteorological
reason why the product was issued.
Procedures
When ever the meteorological criteria for a Red Flag event are occurring
or expected to occur within 72 hours, the NWS office will contact
the land management agencies to obtain a determination of fire danger.
If the the combined fire danger rating and meteorological criteria
warrant a Red Flag product, the NWS and land management agencies will
reach a consensual on whether to issue the product, and for which
areas at which times. (TOP)
SC Red Flag Fire Alert
A Red Flag Fire Alert will be issued by the South Carolina Forestry
Commission (SCFC) with the meteorological input from the NWS Forecast
Office in Columbia. The Alert will be issued when conditions that
support potentially destructive forest fires are worsening. It will
continue in effect until the SCFC cancels it.
(TOP)
The NWS office in Columbia, South Carolina, will transmit Red Flag Fire Alerts for all of South Carolina, as a cooperative service to the SCFC. These will be delivered under the product header, Rangeland Fire Danger Statement. The text will be preformatted, with the body of the alert written by the SCFC.
Fire Danger Statements and Blow-Up Alerts
When fire danger or fire occurrence is high and is coupled with critical
weather conditions, user agencies may request that the NWS issue a
Fire Danger Statement or Blow-Up Alert. These statements will be issued
in coordination with the requesting agency and will only be issued
with their approval. The NWS will use the Special Weather Statement
(SPS) for these issuances, with the headline "...Fire Danger Statement...", and the following call to action statement: "Please refer to your local burn permitting authorities on whether you can burn today. If you do burn...you are advised to use extreme caution."
Participation in Interagency Groups
The NWS and its customers will meet from time to time, for the
purpose of reviewing the operational relationships agreed to in
this plan, and as partners in other interagency meetings.
Meetings may be between one NWS office and all of its customers
from several states, a state meeting of all NWS offices and fire
weather customers within South Carolina, or a meeting conducted
by a customer group with the NWS offices invited either individually
or collectively.
Customers may at times invite NWS representatives to serve on an
interagency group at either the state or national level. These groups
may serve a variety of purposes, such as program review, service
evaluation, scientific advisory, or joint decision making.
Special fire weather services are those services that are uniquely
required by land management agencies and go beyond the normal forecast
operations of the NWS. Special services include the Advanced Technology
Meteorological Unit (ATMU), the All Hazards Meteorological Response System (AMRS),
Incident Meteorologist (IMET) deployment, station visits, weather observer training,
participation in user agency personnel training, and other pertinent meteorological
services.
Typically, special services require NWS personnel to be away from
the Forecast Office and, in some instances, be in overtime status.
User agencies are responsible for covering the cost of NWS overtime,
travel and per diem expenses. Reimbursement of costs for special
services will be as outlined in the Interagency
Agreement for Meteorological Services
The Advanced Technology Meteorological Unit (ATMU) is a modularized
and mobile system of equipment used by an Incident Meteorologist
(IMET) for data collection and product preparation. The ATMU is
a national resource. There are 25 ATMUs cached around the country,
mostly in the western states. The nearest ATMU
cache to South Carolina is London, KY, where
two are maintained.
The ATMU consists of two (2) modules. The first module contains
a theodolite with tripod, a belt weather kit, Pibal weather balloons,
a nozzle and regulator for a helium tank, and office supplies and
miscellaneous expendables. Its volume is 13.8 cubic feet and it weighs
122 pounds.
The second module, known as the AMRS, contains a laptop
computer, a satellite dish for obtaining weather data, and a printer.
This module is also a national resource, but is located at the National
Weather Service offices that have an IMET on station. The volume of the
satellite dish is 13.8 cubic feet, and it weighs 122 pounds.
Requests for the ATMU, AMRS, and IMET should be made through the
local Interagency State Coordination Center. Typically, the IMET
nearest the incident will be deployed. However, during times of
limited resources, IMETs from other areas of the country may be
called. This decision will be made by the Special Meteorologist
to NIFC (SMN) in conjunction with the MIC and IMET from the affected
offices.
The mobilization of the ATMU, AMRS and the IMET is coordinated
through the local State Interagency Coordination Center, the Southern
Area Interagency Fire Cache, and the Southern Area
Coordination Center (SACC). Demobilization is initiated at the incident,
and coordinated through the Coordination Centers previously mentioned.
For more specific information, reference the Southern Area and the
National Interagency Mobilization Guides.
The requesting agency is responsible for any storage of the unit
while in transit, and shelter for the IMET and unit at the site.
A sheltered work area, of at least 50 square feet with a table and
chair, must be protected from excessive dust, free of standing water
or condensation, and must be heated and/or cooled sufficiently to
allow efficient operation of equipment. Power (120V AC) must be
provided for the ATMU's electrical equipment and priority telephone
access during certain short periods each day must be made available.
Upon arrival at the incident and after going through the appropriate
check-in procedures, the IMET will:
- Brief the Fire Behavior Analyst (FBAN), Planning Section Chief
(PSC), and the Incident Commander (IC) on current and expected
weather as it affects the fire.
- Establish a schedule with the IC and the FBAN for written forecasts
and formal briefings.
- Request a briefing of the fire situation and potential behavior
problems from the FBAN. As time and resources permit, incident
management should arrange for an aerial inspection trip for the
meteorologist and should provide the forecaster with current fireline
maps. If possible, the IMET should be assigned a radio with the
fireline frequency.
- Arrange for a schedule of observations from key points around
the fire and from nearby lookouts and fire danger stations, in
cooperation with the FBAN and PSC. On large fires, some personnel
(at least two) should be permanently assigned to this duty. On
smaller fires, this information can be provided by Division Supervisors
equipped with belt weather kits.
(TOP)
NWS meteorologists will be available to assist in user-oriented
training, such as at fire behavior schools (e.g. S-290), and weather
related courses. Requests should be made through the Meteorologist-in-Charge
as early as possible after dates for such training have been determined.
Other special services include weather station visits by user agency
personnel, weather observer training, and course development work.
These activities would typically be at the full expense of the requesting
agency unless other arrangements have been made.
(TOP)
The primary means of communication used by the NWS is Advanced
Weather Interactive Processing System (AWIPS). Products transmitted
through AWIPS include: pre-suppression forecasts, Fire Weather Watches,
Red Flag Warnings, Fire Danger statements, and NFDRS station forecasts.
Spot forecasts will be disseminated to the requesting agency by
means of the internet, with telefax (FAX) as a backup. Anytime a
request for a spot forecast is made by fax , the requesting agency
must include a FAX number. A voice number should also be included
in the event problems or questions arise with the request, the forecast,
or the transmission.
Public products produced by the National Weather Service are available
over NOAA Weather Radio (NWR). As of January 31, 2003, the following
NWR transmitters service South
Carolina: (map)
Site, Call Sign, Frequency, NWS Office:
BARNWELL, KHC29, 162.500, COLUMBIA, SC
BEAUFORT, WXJ23, 162.450, CHARLESTON, SC
CHARLESTON, KHB29, 162.550, CHARLESTON, SC
CHERAW, WXK90, 162.450, COLUMBIA, SC
COLUMBIA, WXJ20, 162.400, COLUMBIA, SC
CONWAY/MYRTLE BEACH, KEC95, 162.400, WILMINGTON, NC
CROSS, WXM93, 162.475, CHARLESTON, SC
FLORENCE, WXJ22, 162.550, WILMINGTON, NC
GREENVILLE, WXJ21, 162.550, GREENVILLE/SPARTANBURG, SC
KIRKSEY, KHC28, 162.425, GREENVILLE/SPARTANBURG, SC
ORANGEBURG, KHA35, 162.525, COLUMBIA, SC
ROCK HILL, KHC27, 162.425, GREENVILLE/SPARTANBURG, SC
SUMTER, WWG77, 162.475, COLUMBIA, SC
AUGUSTA, GA, WXK54, 162.550, COLUMBIA, SC
CLAYTON, GA, KXI81, 162.450, GREENVILLE/SPARTANBURG, SC
SAVANNAH, GA, KEC85, 162.400, CHARLESTON, SC
TOCCOA, GA, WWH24, 162.425, GREENVILLE/SPARTANBURG, SC
WAYNESBORO, GA, WXM88, 162.425, COLUMBIA, SC
CHARLOTTE, NC, WXL70, 162.475, GREENVILLE/SPARTANBURG, SC
FAYETTEVILLE, NC, WXL50, 162.475, RALEIGH/DURHAM, NC
LUMBER BRIDGE, NC, WWF89, 162.525, WILMINGTON, NC
BADIN, NC, WWF60, 162.425, RALEIGH/DURHAM, NC
Other means of communications may be utilized upon mutual agreement
with user agencies.
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