Extended Abstract

G3normalized by the total number of days with precipitation (no precipitationspoints are not considered). The model forecasts were taken from the nearestpoint. We can see for all cases that both models represent the monthlyfrequency of observed precipitation, with maximum frequency in the 20 to40mm and a sudden drop to the 60mm and higher categories. For almost all themonth and categories analyzed, the high resolution adjusts better to theobservations. In Table 1 the extreme categories are presented showing that thetotal number of cases with high precipitation is better represented by the HighResolution model while the Regional model clearly shows a dry bias above100mm.Table 1: As Figure 1 but for the total number of cases observed during the two summerseasons considered for the highest precipitating categories.Category OBS High RegionalResolution ETA/SMN100 37 28 0120 14 6 2140 9 0 0160 6 0 0In terms of monthly totals, both models represent the same precipitationpatterns, but the high resolution model can attain higher values when aconvective month is present. One of such example is shown in Figure 2, wherewe can appreciate differences of more than 200mm between models, andcomparing to the observations the high resolution has the best fit, while theRegional ETA/SMN model under forecasted significantly the monthly totals.Total observed precipitation for FEBRUARY 2010-29-31-33500450400350300250-35200150-3710050-39-66 -64 -62 -60 -58 -560Figure 2: Monthly precipitation totals of 12-36hs forecast from the Non Hydrostatic HighResolution forecast ETA model (left) and Regional ETA model (center), and observed(right) for February 2010Looking into daily totals we can see that the differences observed in Figure 2come from particular days where high precipitation was forecasted andobserved (Figure 3).3-354-