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. | ||
Critical Fire 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) |
Weather Feature |
Origin and Thresholds |
Severe Thunderstorms |
SPC convective outlook slight risk contour (chance of severe weather within 25 miles of a certain point). |
Flash flooding |
WPC excessive rainfall outlook slight risk contour (10-20% chance of exceeding flash flood guidance within 25 miles of 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 |
Critical Fire Weather |
The critical fire weather threat polygon from the SPC Fire Weather Outlooks |
General Weather |
WPC Quantitative Precipitation Forecasts for coverage, and weather type from the NWS NDFD forecasts |
Fronts and low/high pressure areas |
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Tropical Systems |
Latest NHC forecast points valid at the same time as the fronts |