For Friday's high temperature in Wichita, Kansas, we have another example where the two main U.S. models are disagreeing strongly. The NAM statistical forecast highs are 55 and 65 F, but the GFS statistical forecasts are in the 80's! So let's forecast Tmax for Wichita and see which model does better. Apparently the name of the airport changed from Mid-Continent to Dwight D. Eisenhower National Airport a few years ago.
Question: Why do the two models disagree so much? Here is a part of the NWS forecast discussion for Wichita; see if you can make sense of it: "Uncertainty grows as we move into Friday, with the NAM/HREF showing the cold front surging southward into the Southern Plains in the wake of the overnight convection. The latest HREF only goes out to 12Z on Fri but it looks strikingly similar to the NAM which keeps all of our forecast area in a stable post-frontal regime on Friday. If the NAM/HREF verify which seems likely, high temperatures may be 15-20 degrees too warm."
Sometimes when the two models disagree, the answer is somewhere in the middle. But in this case, the NAM model was very right and the GFS was wrong, wrong, wrong. All of the GFS runs, even the very latest one, insisted that the high temperature would be in the 80's at Wichita, but instead it only reached 66 F in the cool, cloudy air to the north of the front. Coffeyville, Kansas reached 80 F, about 150 miles to the southeast. So strong fronts can sometimes cause large forecast errors.
Forecaster | Tmax, deg F (error) | Comment | Day Score |
---|---|---|---|
OBSERVED | 66 | Tmax FINAL (minor problem). | |
1. Jasper15 | 67 (1) | 3.4 | |
NAM-MOS-00-DAY01 | 65 (-1) | 3.4 | |
2. Hailey15 | 68 (2) | 3.2 | |
2. Mikayleigh15 | 68 (2) | 3.2 | |
NAM-MOS-12-DAY01 | 68 (2) | 3.2 | |
2. Hannah15 | 68 (2) | 3.2 | |
NAM-MOS-00-DAY00 | 70 (4) | 2.9 | |
5. Shelby15 | 70 (4) | 2.9 | |
5. Shyann15 | 70 (4) | 2.9 | |
5. ashleigh15 | 62 (-4) | 2.9 | |
8. Emily15 | 61.6 (-4.4) | 2.8 | |
CLIMATE | 61.6 (-4.4) | NCDC Climate Normals, 1981-2010 | 2.8 |
9. Grace15 | 72 (6) | 2.5 | |
9. Gianni15 | 60 (-6) | 2.5 | |
9. EmilyV15 | 72 (6) | 2.5 | |
9. T-Dawg15 | 72 (6) | 2.5 | |
9. Anna15 | 72 (6) | 2.5 | |
14. Elizabeth15 | 73 (7) | 2.3 | |
14. Miles15 | 73 (7) | 2.3 | |
14. kendra15 | 73 (7) | 2.3 | |
14. Dorothy15 | 73 (7) | 2.3 | |
18. Joscelyn15 | 73.5 (7.5) | 2.3 | |
18. Alex15 | 73.5 (7.5) | 2.3 | |
PERSISTENCE | 74 (8) | 2.2 | |
20. Leah15 | 74 (8) | 2.2 | |
21. Lizzie15 | 75 (9) | 2.0 | |
21. Abbygale15 | 75 (9) | 2.0 | |
21. Mathison15 | 75 (9) | 2.0 | |
21. Autumn15 | 75 (9) | 2.0 | |
25. Django15 | 76 (10) | 1.8 | |
NAM-MOS-12-DAY02 | 55 (-11) | 1.7 | |
26. Josh15 | 78 (12) | The two models disagree so much because one is taking in account that the cold front will not arrive that quick so it will be in a post-frontal regime. | 1.5 |
GFS-MOS-06-DAY02 | 80 (14) | 1.2 | |
27. Eavenly15 | 81 (15) | humidity ?? | 1.0 |
28. EmilyS15 | 82 (16) | 0.8 | |
GFS-MOS-12-DAY02 | 82 (16) | 0.8 | |
GFS-MOS-00-DAY01 | 83 (17) | 0.7 | |
GFS-MOS-18-DAY02 | 83 (17) | 0.7 | |
GFS-MOS-00-DAY00 | 84 (18) | 0.5 | |
29. Briley15 | 84 (18) | Yee | 0.5 |
GFS-MOS-12-DAY01 | 85 (19) | 0.3 | |
GFS-MOS-18-DAY01 | 87 (21) | 0 | |
30. Gus15 | 41 (-25) | 0 |