Tables


Table 1: Relative errors for the 48 h forecasted vertical wind shear (VWS) from the AVN model for selected locations and the overall average during August and September 1993. Errors (in ms-1) are expressed as observed minus forecasted VWS such that positive values indicate more VWS was observed than forecasted. The type of observed winds (west, east, west < 10 ms-1 and west 10 ms-1) refer to the 200 mb wind flow at the particular location at the verification time 48 h (t = 48). Number of cases are in parenthesis.


Category 15 N, 80 W 15 N, 70 W 20 N, 65 W 12.5 N, 60 W Avg
All Cases (t = 48) 5.7 (63) 6.1 (63) 2.2 (63) 2.0 (63) 4.0 (252)
West (t = 48) 7.7 (37) 7.4 (43) 3.5 (47) 4.6 (30) 5.8 (157)
East (t = 48) 2.8 (26) 3.4 (20) -1.6 (16) -0.4 (33) 1.1 (95)
West < 10 ms-1 (t = 48) 7.3 (26) 5.2 (30) 2.6 (24) 3.5 (23) 4.7 (103)
West 10 ms-1 (t = 48) 8.6 (11) 12.5 (13) 4.5 (23) 8.3 (7) 7.8 (54)



Table 2: Average relative forecast errors (in ms-1) for the 48 h VWS from the AVN model during August and September 1993 stratified by winds observed at initialization (t = 0) and 48 h later (t = 48). Number of cases are in parenthesis. Due to missing wind observations coinciding with model initialization, there are 4 fewer total cases than in Table 1 (248).


Category East (t = 48) West < 10 ms-1 (t = 48) West 10 ms-1 (t = 48)
East (t = 0) 1.4 (51) 5.8 (37) 8.8 (6)
West < 10 ms-1 (t = 0) 1.3 (33) 5.0 (44) 7.2 (25)
West 10 ms-1 (t = 0) -2.3 (8) 2.3 (21) 8.1 (23)



Table 3: 1979-1988 Climatological VWS values (in ms-1) for mid-August, late August, mid-September, and late September.


Date 15 N, 80 W 15 N, 70 W 20 N, 65 W 12.5 N, 60 W
Mid-August 14.6 14.7 10.5 8.3
Late August 12.6 14.1 9.9 9.1
Mid-September 10.7 13.5 9.3 9.9
Late September 11.1 14.0 10.6 13.4



Table 4: Average relative forecast errors (in ms-1) for the 48 h VWS of all wind stratifications at model initialization (t = 0) using the AVN prognostic field, persistence, and climatology. The number of cases are the same as Table 2.


Category AVN Persistence Climatology
All Cases (t = 0)4.0 -0.1 1.3
West (t = 0) 4.3 -1.9 2.1
East (t = 0) 3.6 2.9 0.1
West < 10 ms-1 (t = 0) 4.3 -1.2 1.2
West 10 ms-1 (t = 0) 4.2 -3.2 3.8





Table 5: Average absolute forecast errors (in ms-1) for the 48 h VWS of all wind stratifications at model initialization (t = 0) using the AVN prognostic field, persistence, and climatology. The number of cases are the same as Table 2.


Category AVN Persistence Climatology
All Cases (t = 0)5.4 4.8 4.5
West (t = 0) 5.6 4.7 4.8
East (t = 0) 5.1 4.9 4.0
West < 10 ms-1 (t = 0) 5.3 4.1 4.0
West 10 ms-1 (t = 0) 6.3 5.8 6.3