This blog entry is written to show the following: Old school techniques are NOT outdated. Using Gene Weber’s rule of the heaviest snow falling along and to the left of the 500mb height fall center track, 4″+ was forecasted for the Omaha metro. The rest of the snowfall forecast made below was a result of using the Garcia Method, where the snowfall amounts relate to the mixing ratios that are found on theta surfaces. Using these 2 techniques, with some but not total reliance on model forecasted qpf, the following forecast was produced:
It is important to note that while model GFS qpf indicated a wide area of 2-6″ across the entire midwest with no concentrated area of 4″+ a few days before the storm, the forecasted HFC track indicated that a concentrated area of 4″+ would be located very close to the above forecast. Thus, it is stressed that model qpf should NOT be soley relied upon for snowfall forecasts. Other techniques should be used. The forecast is only as good as the time and effort put in by the forecaster. Here are actual snow totals:
The forecasted HFC track almost exactly showed where the 4″ cutoff would be. And now a look at Iowa’s snow totals:
While model qpf suggested that heavy snow would extend into northeastern Iowa, the Garcia Method suggested that the 4″ cutoff would occur as forecasted. This proves the value of this method.
There were some 2″ amounts in western Iowa, which was surprising. This was not forecasted, but these amounts were also not consistent with the 4-7″ surrounding them. This made these amounts hard to forecast. Some 8″ amounts were also reported over northwestern Iowa, which should have also been accounted for in the forecast.
Overall, however, I think that the forecast worked out very well. Models did not do that bad about a day before the storm, but they could have definitely been approved upon by using various techniques.
Ross
