The plot for each station contains 4 traces of hourly NAM model output.
TRACE 1: TMPF, DWPF - Temperature (red), Dew Point (green): 2-meter values in degrees F. The scale is fixed to 17-42 with a dotted line at 32, designed to focus on temperatures close to the freezing mark.
TRACE 2: P01M - Precipitation(orange line), hourly accumulations in inches and WSYM - Bottom Line: weather symbols using the Ramer algorithm
- Center Line: weather symbols using the operational NCEP precipitation type algorithm based on Baldwin and Contorno (13th WAF Conference)
- Top Line: weather symbols using the dominant type among the 5 algorithms
TRACE 3: WSYM - Bottom Line: weather symbols using the alternate NCEP precipitation type algorithm
- Center Line: weather symbols using the Bourgouin algorithm
- Top Line: weather symbols using the explicit microhysics in the model
SNRA - percentage of frozen precip(green line) direct from the NAM microphysics
TRACE 4: TMPF - Temperature values (degrees C) at various pressure levels: 950mb (dark red), 900 (red), 850 (orange), 800 (light orange) 750 (pink) 700 (gold). This is meant to give a quick look at the vertical thermal structure. A complete inspection of the forecast sounding is recommended.
Read some comments on how to apply the data.
A quick comment regarding the methodology of this system: While the usage of multiple algorithms can be considered a mini-"ensemble", this ensemble does not attempt to sample initial condition uncertainty. If the operational NAM forecast contains large synoptic errors, this output will be of lesser value, as it assumes an accurate forecast of the thermal profile. It only accounts for uncertainty related to how different algorithms handle thermal profiles, not the uncertainty of the thermal profiles themselves. To examine the model uncertainty, please look at output from the SREF system. The SREF system now uses this multiple algorithm approach for its precipitation type forecast.
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