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CastCheck methodology v0.2 · data through 2026-08-30

Trenton Mercer · ECMWF AIFS Single · lead day 1

KTTN · aifs_single · lead 1

Target day = initialization date + 1 day. This page is a permanent link: the numbers change as history accumulates, the address and the methodology version do not.

Scores use the latest model version segment, aifs-single-gpid5, starting 2026-08-01 — days before that ran a different version of the model and are excluded rather than silently pooled. Of the scored days, 1 carry a QC flag on the observation.

JSON for this page CSV of the daily errors Cite this page

Every number for this combination

All four windows × both initializations × both interpolations × both variables. Errors are computed in °C and shown in °F; CI is a 95 % moving-block bootstrap interval. MAE debiased and skill, debiased remove the constant offset of the window first, so a station that the model always reads a degree too warm is not scored as if it had no skill — compare the two skill columns to see how much of the error is a fixed offset. n QC next to n counts days whose observation carries a QC flag.

VariableInitMethod Windown MAE °F MAE debiased Bias °F RMSE °F ±1 °F±2 °F±3 °F Skill Skill, debiased Period
tmax00Zbilinear30d29 1 QC1.75 [1.27, 2.23]1.59+0.67 [-0.64, 1.80]2.16 [1.59, 2.62]34% [17%, 53%]69%86%+0.26+0.322026-08-02 → 2026-08-30
tmax00Zbilinear90d29 1 QC1.75 [1.21, 2.27]1.59+0.67 [-0.77, 1.78]2.16 [1.39, 2.70]34% [16%, 54%]69%86%+0.26+0.322026-08-02 → 2026-08-30
tmax00Zbilinear365d29 1 QC1.75 [1.20, 2.30]1.59+0.67 [-0.77, 1.94]2.16 [1.34, 2.73]34% [14%, 56%]69%86%+0.26+0.322026-08-02 → 2026-08-30
tmax00Zbilinearall29 1 QC1.75 [1.18, 2.31]1.59+0.67 [-1.05, 1.76]2.16 [1.33, 2.75]34% [14%, 57%]69%86%+0.26+0.322026-08-02 → 2026-08-30
tmax00Znearest30d29 1 QC1.90 [1.33, 2.48]1.63+0.98 [-0.35, 2.16]2.33 [1.67, 2.85]31% [10%, 52%]62%83%+0.19+0.302026-08-02 → 2026-08-30
tmax00Znearest90d29 1 QC1.90 [1.28, 2.52]1.63+0.98 [-0.51, 2.11]2.33 [1.51, 2.91]31% [12%, 50%]62%83%+0.19+0.302026-08-02 → 2026-08-30
tmax00Znearest365d29 1 QC1.90 [1.25, 2.59]1.63+0.98 [-0.47, 2.29]2.33 [1.44, 2.94]31% [10%, 55%]62%83%+0.19+0.302026-08-02 → 2026-08-30
tmax00Znearestall29 1 QC1.90 [1.26, 2.55]1.63+0.98 [-0.76, 2.09]2.33 [1.43, 2.95]31% [11%, 56%]62%83%+0.19+0.302026-08-02 → 2026-08-30
tmax12Zbilinear30d29 1 QC1.85 [1.43, 2.33]1.52+0.87 [-0.10, 1.93]2.14 [1.73, 2.55]24% [7%, 43%]55%90%+0.21+0.352026-08-02 → 2026-08-30
tmax12Zbilinear90d29 1 QC1.85 [1.29, 2.33]1.52+0.87 [-0.31, 1.92]2.14 [1.59, 2.57]24% [9%, 47%]55%90%+0.21+0.352026-08-02 → 2026-08-30
tmax12Zbilinear365d29 1 QC1.85 [1.28, 2.37]1.52+0.87 [-0.27, 2.08]2.14 [1.53, 2.61]24% [6%, 50%]55%90%+0.21+0.352026-08-02 → 2026-08-30
tmax12Zbilinearall29 1 QC1.85 [1.34, 2.34]1.52+0.87 [-0.47, 1.88]2.14 [1.63, 2.59]24% [7%, 47%]55%90%+0.21+0.352026-08-02 → 2026-08-30
tmax12Znearest30d29 1 QC2.05 [1.55, 2.64]1.54+1.20 [0.21, 2.30]2.33 [1.82, 2.86]21% [3%, 41%]52%83%+0.13+0.342026-08-02 → 2026-08-30
tmax12Znearest90d29 1 QC2.05 [1.42, 2.64]1.54+1.20 [0.01, 2.29]2.33 [1.70, 2.88]21% [5%, 46%]52%83%+0.13+0.342026-08-02 → 2026-08-30
tmax12Znearest365d29 1 QC2.05 [1.42, 2.69]1.54+1.20 [0.04, 2.45]2.33 [1.67, 2.94]21% [4%, 50%]52%83%+0.13+0.342026-08-02 → 2026-08-30
tmax12Znearestall29 1 QC2.05 [1.47, 2.64]1.54+1.20 [-0.16, 2.27]2.33 [1.73, 2.88]21% [4%, 44%]52%83%+0.13+0.342026-08-02 → 2026-08-30
tmin00Zbilinear30d29 1 QC4.00 [3.55, 4.47]1.39+4.00 [3.55, 4.47]4.33 [3.88, 4.79]0% [0%, 0%]14%31%-0.33+0.532026-08-02 → 2026-08-30
tmin00Zbilinear90d29 1 QC4.00 [3.50, 4.49]1.39+4.00 [3.50, 4.49]4.33 [3.82, 4.82]0% [0%, 0%]14%31%-0.33+0.532026-08-02 → 2026-08-30
tmin00Zbilinear365d29 1 QC4.00 [3.47, 4.53]1.39+4.00 [3.47, 4.53]4.33 [3.76, 4.88]0% [0%, 0%]14%31%-0.33+0.532026-08-02 → 2026-08-30
tmin00Zbilinearall29 1 QC4.00 [3.49, 4.51]1.39+4.00 [3.49, 4.51]4.33 [3.75, 4.88]0% [0%, 0%]14%31%-0.33+0.532026-08-02 → 2026-08-30
tmin00Znearest30d29 1 QC4.26 [3.82, 4.70]1.41+4.26 [3.82, 4.70]4.57 [4.13, 5.02]0% [0%, 0%]14%28%-0.42+0.532026-08-02 → 2026-08-30
tmin00Znearest90d29 1 QC4.26 [3.79, 4.72]1.41+4.26 [3.79, 4.72]4.57 [4.07, 5.05]0% [0%, 0%]14%28%-0.42+0.532026-08-02 → 2026-08-30
tmin00Znearest365d29 1 QC4.26 [3.74, 4.75]1.41+4.26 [3.74, 4.75]4.57 [4.02, 5.09]0% [0%, 0%]14%28%-0.42+0.532026-08-02 → 2026-08-30
tmin00Znearestall29 1 QC4.26 [3.77, 4.74]1.41+4.26 [3.77, 4.74]4.57 [4.01, 5.12]0% [0%, 0%]14%28%-0.42+0.532026-08-02 → 2026-08-30
tmin12Zbilinear30d29 1 QC4.11 [3.67, 4.59]1.48+4.11 [3.67, 4.59]4.46 [4.09, 4.86]3% [0%, 10%]10%31%-0.37+0.502026-08-02 → 2026-08-30
tmin12Zbilinear90d29 1 QC4.11 [3.64, 4.61]1.48+4.11 [3.64, 4.61]4.46 [4.04, 4.89]3% [0%, 10%]10%31%-0.37+0.502026-08-02 → 2026-08-30
tmin12Zbilinear365d29 1 QC4.11 [3.61, 4.66]1.48+4.11 [3.61, 4.66]4.46 [4.00, 4.95]3% [0%, 11%]10%31%-0.37+0.502026-08-02 → 2026-08-30
tmin12Zbilinearall29 1 QC4.11 [3.63, 4.62]1.48+4.11 [3.63, 4.62]4.46 [4.03, 4.96]3% [0%, 10%]10%31%-0.37+0.502026-08-02 → 2026-08-30
tmin12Znearest30d29 1 QC4.36 [3.93, 4.81]1.49+4.36 [3.93, 4.81]4.70 [4.33, 5.08]0% [0%, 0%]10%28%-0.45+0.502026-08-02 → 2026-08-30
tmin12Znearest90d29 1 QC4.36 [3.92, 4.82]1.49+4.36 [3.92, 4.82]4.70 [4.28, 5.11]0% [0%, 0%]10%28%-0.45+0.502026-08-02 → 2026-08-30
tmin12Znearest365d29 1 QC4.36 [3.89, 4.87]1.49+4.36 [3.89, 4.87]4.70 [4.24, 5.16]0% [0%, 0%]10%28%-0.45+0.502026-08-02 → 2026-08-30
tmin12Znearestall29 1 QC4.36 [3.90, 4.84]1.49+4.36 [3.90, 4.84]4.70 [4.26, 5.16]0% [0%, 0%]10%28%-0.45+0.502026-08-02 → 2026-08-30

+ model too warm · − model too cold · bias interval includes zero · ★ lowest MAE · = not distinguishable from the leader · ▼ significantly worse · n < 30 greyed and unranked · CI is a 95 % moving-block bootstrap interval.

Daily error, last 90 days

Daily forecast minus observed error in °F for ECMWF AIFS Single at KTTN, lead day 1, 00Z bilinear tmax+10+50-5-102026-08-02: -0.91 °F2026-08-03: -5.48 °F2026-08-04: +0.31 °F2026-08-05: -1.78 °F2026-08-06: -0.01 °F2026-08-07: -2.8 °F2026-08-08: +0.64 °F2026-08-09: +2.38 °F2026-08-10: +2.54 °F2026-08-11: +4.34 °F2026-08-12: +1.06 °F2026-08-13: +2.42 °F2026-08-14: +3.43 °F2026-08-15: +1.39 °F2026-08-16: +3.89 °F2026-08-17: +1.52 °F2026-08-18: +2.46 °F2026-08-19: +0.54 °F2026-08-20: -1.84 °F2026-08-21: -0.97 °F2026-08-22: -0.67 °F2026-08-23: +0.45 °F2026-08-24: +1.24 °F2026-08-25: +1.38 °F2026-08-26: +1.97 °F2026-08-27: -0.37 °F2026-08-28: +1.06 °F2026-08-29: +1.98 °F2026-08-30: -0.8 °F2026-08-022026-08-30°F, forecast − observed
Forecast − observed, °F, 00Z bilinear daily maximum. The dashed line is zero; the thick line is a centred 7-day mean, drawn only where the whole window is present. Gaps are days with no score, never interpolation. Hover a point for its date and value.
The same series as a table (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-0.80
2026-08-29+1.98
2026-08-28+1.06
2026-08-27-0.37
2026-08-26+1.97
2026-08-25+1.38
2026-08-24+1.24
2026-08-23+0.45
2026-08-22-0.67
2026-08-21-0.97
2026-08-20-1.84
2026-08-19+0.54
2026-08-18+2.46
2026-08-17+1.52
2026-08-16+3.89
2026-08-15+1.39
2026-08-14+3.43
2026-08-13+2.42
2026-08-12+1.06
2026-08-11+4.34
2026-08-10+2.54
2026-08-09+2.38
2026-08-08+0.64
2026-08-07-2.80
2026-08-06-0.01
2026-08-05-1.78
2026-08-04+0.31
2026-08-03-5.48
2026-08-02-0.91

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, lead day 1-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 1 day-5 to -4 °F: 0 days-4 to -3 °F: 0 days-3 to -2 °F: 1 day-2 to -1 °F: 2 days-1 to 0 °F: 6 days0 to 1 °F: 4 days1 to 2 °F: 8 days2 to 3 °F: 4 days3 to 4 °F: 2 days4 to 5 °F: 1 day5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 1.39 · P90 |e| 3.52 °F-100+10 °Fn = 29 days
All scored days for 00Z bilinear daily maximum, 20 equal bins. The dashed marks are the 50th and 90th percentiles of the absolute error, mirrored on both sides. Hover a bar for its bin and count.
Bin counts as a table
From °FTo °FDays
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.001
-5.00-4.000
-4.00-3.000
-3.00-2.001
-2.00-1.002
-1.00+0.006
+0.00+1.004
+1.00+2.008
+2.00+3.004
+3.00+4.002
+4.00+5.001
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08291.75 +0.67

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means ECMWF AIFS Single has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
Aurora (GFS init) 1 -1.63 [-1.63, -1.63] yes
Aurora (IFS init) 2 +0.85 [-0.18, 1.88] no
FourCastNet v2 (GFS init) 1 -0.40 [-0.40, -0.40] yes
FourCastNet v2 (IFS init) 2 -1.27 [-1.34, -1.19] yes
NCEP GFS 29 -1.20 [-2.16, -0.28] yes
GraphCast (GFS init) 1 -2.64 [-2.64, -2.64] yes
GraphCast (IFS init) 27 -0.59 [-2.00, 0.64] no
ECMWF IFS HRES 23 -0.94 [-1.72, 0.25] no
Pangu-Weather (GFS init) 1 -1.66 [-1.66, -1.66] yes
Pangu-Weather (IFS init) 2 -1.41 [-2.09, -0.74] yes
Persistence (baseline) 29 -0.60 [-1.62, 0.45] no

Cite this page

ShortCastCheck, KTTN aifs_single lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KTTN/model/aifs_single/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model aifs_single, lead day 1. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KTTN/model/aifs_single/lead/1/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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