Description
The WPC National Forecast Charts provide an overview of expected weather for up to the next three days, with emphasis on certain hazardous and significant weather. They summarize forecasts from several NCEP Service Centers including the Storm Prediction Center (for severe thunderstorm and tornado outlooks), the National Hurricane Center (for tropical storm and hurricane forecasts), and the Weather Prediction Center (for information concerning heavy rainfall, flooding, winter weather, and general weather). With overlaid frontal forecasts, these displays serve as a good overview of the expected weather for the next two days.
The charts are 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. They show the large-scale weather features and associated significant weather. These charts are especially useful to travelers or others needing a big picture forecast. They are 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 Day 1 (today's) National Forecast Chart is prepared twice daily at the WPC. The initial product is issued by 5 a.m. EST/EDT, with an update provided by 2200 UTC (5 p.m. EST).
Feature |
Valid Times for Day 1 - |
Valid Times for Day 2 (Tomorrow) |
Surface features such as highs, lows, and fronts | AM issuance: 1200 UTC (7 a.m. EST) | AM issuance: 1200 UTC (7 a.m. EST) tomorrow or 1200 UTC Day 3. |
PM issuance: 0000 UTC (7 p.m. EST) | ||
General precipitation areas |
AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) of the current day. | AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) tomorrow or 1200 UTC Day 3. |
PM issuance: 12-hour period from 0000 UTC to 1200 UTC (7 p.m.-7 a.m. EST) | ||
Severe weather |
AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) of the current day. | AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) tomorrow or 1200 UTC Day 3. |
PM issuance: 16-hour period starting at 2000 UTC (3 p.m. EST) of the current day. | ||
Winter weather forecasts | AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) of the current day. | AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) tomorrow or 1200 UTC Day 3. |
PM issuance: 12-hour period starting at 0000 UTC (7 p.m. EST) of the current day. | ||
Flash flooding forecasts | AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) of the current day. | AM issuance: 24-hour period starting at 1200 UTC (7 a.m. EST) tomorrow or 1200 UTC Day 3. |
PM issuance: From issuance time through 1200 UTC (7 a.m. EST tomorrow) |
The National Forecast Charts depict the location of frontal systems and pressure centers over the continental United States and include several weather parameters derived from forecast charts prepared by other NCEP Service Centers. See Table 2 for the sources of the forecasts.
Weather Feature |
Origin and Thresholds |
Severe Thunderstorms |
SPC convective outlook slight risk contour (15% chance of severe weather within 25 miles of a certain point). |
Flash flooding |
WPC excessive rainfall outlook slight risk contour (5% chance of exceeding flash flood guidance at a certain point). |
Heavy Snow |
WPC winter weather probabilistic forecasts showing at least a 30% chance of meeting or exceeding local winter storm warning criteria |
Freezing Rain |
WPC freezing rain forecasts of at least 0.01" of ice produced by the WPC winter weather desk |
General Weather |
WPC Quantitative Precipitation Forecasts for coverage, and weather type from the NWS NDFD forecasts |
Fronts and low/high pressure areas |
|
Tropical Systems |
Latest NHC forecast points valid at the same time as the fronts |
We are always seeking to improve our products based on user feedback. Comments concerning this and other WPC products can be sent through the “Contact Us” section of the WPC webpage at http://www.wpc.ncep.noaa.gov/mail_webmaster.