About the Medium Range Forecast

Issuance Times

Product Time
Day 3-7 Fronts/Pressure Graphics for North America 0330 UTC and 1530 UTC
Day 3-7 Min/Max/PoPs 0530 UTC and 1430 UTC
CONUS Grids 0615 UTC and 1530 UTC
Preliminary Discussion 0900 UTC
Preliminary Day 3-7 500mb Height Forecasts 1200 UTC
Updated Preliminary Day 3-7 Fronts/Pressure Graphics 1315 UTC
Preliminary Day 3-7 Min/Max/PoPs 1400 UTC
Updated Preliminary Discussion 1400 UTC
Preliminary WPC Grids 1500 UTC
Final Day 3-7 Fronts/Pressure Graphics 1900 UTC
Final Day 3-7 Min/Max/PoPs 1900 UTC
Final Day 3-7 500mb Height Forecasts 1930 UTC
Final Discussion 1930 UTC
Final WPC Grids 2000 UTC

About These Products

The medium range graphical forecast products include:
  • Surface pressure patterns, circulation centers, fronts, and 500mb heights for days 3-7 into the future
  • Daily maximum and minimum temperatures and anomalies for days 3-7
  • Daily precipitation probabilities for days 3-7
  • A 48-hour QPF encompassing days 4 through 5
  • Total 5-day precipitation for days 1 through 5

The surface pressure and fronts graphics are generated three times per day, while the 500mb forecasts and Min/Max/PoP graphics are issued twice per day. The 0900 UTC and 1400 UTC sets of graphics are preliminary and unofficial, intended for inter-office coordination purposes only. The surface pressure patterns and fronts on the preliminary forecasts are only drawn for the continental U.S. The final set of graphics is issued by 1900 UTC, with the surface pressure patterns and fronts encompassing much of the Northern Hemisphere.

In addition to the graphical forecasts, the forecasters prepare three daily written discussions. The preliminary narrative highlights medium-range model differences and provides initial model preferences, and is available by 0900 UTC. This discussion is updated by 1400 UTC to incorporate significant changes to MOS (Model Output Statistics) and updated global model and ensemble guidance. The final discussion incorporates the latest model guidance and updates forecast reasoning/model preferences. In addition, it highlights any significant weather expected to impact the continental U.S. during the day 4-7 time frame. Forecasters also provide a separate discussion describing model differences and preferences across Hawaii by 1130 UTC.

One meteorologist works during the overnight hours, while two prepare the forecasts during the day shift (1030-1930 UTC). The overnight forecaster generates the initial set of preliminary 3-7 day pressure systems/fronts and discussion due at 0900 UTC. During the day shift, one of the meteorologists updates the preliminary forecasts and issues preliminary 500mb height graphics, then, late in the shift, issues a final discussion and a set of 3-7 day pressure systems/fronts and 500mb forecasts. The other forecaster prepares the 5-day precipitation, 3-7 day temperature and PoP progs, and Hawaiian discussion. They routinely use output from the GFS, ECMWF, and UKMET medium range models and also consider the Canadian, the Navy's NOGAPS model, and ensemble guidance from the GFS, ECMWF, Canadian, and North American Ensemble Forecast System (NAEFS).

During hurricane season, at 1200 noon ET time on a daily basis since June 1, 1997, the medium range pressure forecaster participates in a conference call with the NHC via the Hurricane Hotline to discuss current and potential tropical activity in the Atlantic and Eastern Pacific oceans and how the medium range models are handling the situation.