About the Quantitative Precipitation Forecasts

About 24 Hour QPF About 6 Hourly QPF

**24 Hour QPF Issuance Times**

Product |
Time |

94q (preliminary Day 1) | 0615Z & 1815Z |

94q (final Day 1) | 1015Z & 2215Z |

98q (preliminary Day 2) | 0700Z & 1900Z |

98q (final Day 2) | 1015Z & 2215Z |

99q | 1015Z & 2215Z |

95e (Day 1-5 total) | 1730Z |

QPFPFD (prelim. Day 1) | 0700Z & 1900Z |

QPFPFD (prelim. Day 2) | 0745Z & 1945Z |

QPFPFD (with Days 1-3) | 1100Z & 2300Z |

**About The 24 Hour QPF Products**

Isohyets of expected areal
average rainfall of .01 inch, .25 inch, .50 inch, 1 inch, 1.50 inch and
greater (in inch increments) are drawn for the 24 hour forecast period
ending at 1200Z on both days 1, 2, and 3. The daily QPF package begins
on the midnight shift with the 0000Z model run. A preliminary Day
1 forecast (94Q) is issued by 06Z and the Final Day 1 (94Q) is issued by
10Z and is valid at 1200Z the following morning. The Day 2 QPF (98Q) is
issued by 1000Z. The Day 2 forecast (98Q) is updated on the day shift and
is issued by 1800Z.
An electronically generated bulletin, which describes the location of the forecast isohyets using latitude and longitude points, is transmitted at the end of the qpf discussion for the Day 1 through Day 3 finals. Example:
The first field is the value of the contour (in this case...0.25" or 0.50"). The following fields are the latitude/longitude pairs for the contour. The first three digits of the pair are the degrees of latitude (in tenths of degrees North latitude). The last three digits of the pair are the degrees of longitude (in tenths of degrees West longitude). If the fourth digit is less than 5, a leading "1" is added to indicate longitudes greater than or equal to 100° W. From the above message...the following table gives the decoded lat/long pairs |

Value: 0.25" |
Value: 0.50" |

35.0N, 73.1W | 40.4N, 107.2W |

34.9N, 76.1W | 39.5N, 107.1W |

34.9N, 78.9W | 39.0N, 107.6W |

34.7N, 80.3W | 38.7N, 108.1W |

34.0N, 81.9W | 38.9N, 108.4W |

32.7N, 83.7W | 39.5N, 108.5W |

31.0N, 85.4W | 40.2N, 108.2W |

29.7N, 86.4W | 40.4N, 107.6W |

28.4N, 87.4W | 40.4N, 107.2W |