The National Forecast Chart

Description
The HPC National Forecast Chart provides an overview of today’s national weather with an emphasis on certain hazardous and significant weather. It summarizes forecasts from several NCEP Service Centers including the Storm Prediction Center (for severe thunderstorm and tornado outlooks), the Tropical Prediction Center (for tropical storm and hurricane forecasts), and the Hydrometeorological Prediction Center (for information concerning heavy rainfall, flooding, winter weather, and general weather). With an overlaid frontal forecast, this display serves as a good overview of the weather for the current day.

The chart is available on the HPC web site at: http://www.hpc.ncep.noaa.gov/noaa/noaa.gif.

Purpose
This chart is intended for use by anyone who needs a non-technical display of the expected weather including the general public, the media, and the emergency management community. It shows the large-scale weather features and associated significant weather. This chart is especially useful to travelers or others needing a big picture forecast. It is not intended to provide detailed local forecasts for any particular area. See http://weather.gov/ for access to detailed local NWS forecasts and warnings.

Availability and Product Valid Times
The National Forecast Chart is prepared twice daily at the HPC.   The initial product is issued by 1000 UTC (5 a.m. EST), with an update provided at 2200 UTC (5 p.m. EST).   Valid times of the features displayed in this product vary depending upon the particular weather phenomenon of interest and issuance time.   See Table 1 below for detailed information regarding the valid times for this product.

Feature	Valid time
Surface features such as highs, lows, and fronts	Morning issuance:  1800 UTC (1 p.m. EST)
	Afternoon issuance:  0600 UTC (1 a.m. EST)
General precipitation areas	Morning issuance:  1200 UTC through 0000 UTC (7 a.m.-7 p.m. EST)
	Afternoon issuance:  0000 UTC through 1200 UTC (7 p.m.-7 a.m. EST)
Severe weather	Morning issuance:  24-hour period starting at 1200 UTC (7 a.m. EST) of the current day.
	Afternoon issuance:  15-hour period starting at 2100 UTC (4 p.m EST) of the current day.
Winter weather and flash flooding forecasts	Morning issuance:  Usually from 1200 UTC through 0000 UTC 7 a.m.-7 p.m. EST). If particularly significant, however, it may extend an additional 12 hours through the night to 1200 UTC of the following morning.
	Afternoon issuance:  The 27-hour period starting at 2100 UTC (4 p.m EST) of the current day.

Table 1. Valid times for various features shown on the National Forecast Chart.

Basis of the National Forecast Chart
The National Forecast Chart depicts the location of frontal systems and pressure centers over the continental United States and includes several weather parameters derived from forecast charts prepared by other NCEP Service Centers. See Table 2 for the sources of the forecasts included on the chart.

Weather Feature	Origin
Severe thunderstorms and tornados	SPC convective outlooks
Tropical Storms and Hurricanes	TPC forecasts
Heavy snow, sleet, and freezing rain	HPC winter weather forecasts
Flash flooding	HPC excessive rainfall forecasts
Fronts and general weather	HPC short-range public products

Table 2. Sources of forecasts depicted on the National Forecast Chart.

See http://www.hpc.ncep.noaa.gov/html/fntcodes2.shtml for an explanation of the symbols used to depict frontal systems on the National Forecast Chart and HPC surface charts.

Feedback
We are always seeking to improve our products based on user feedback. Comments concerning this and other HPC products can be sent through the “Contact Us” section of the HPC webpage at http://www.hpc.ncep.noaa.gov/mail_webmaster.