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

Trenton Mercer · ECMWF AIFS Single · lead day 6

KTTN · aifs_single · lead 6

Target day = initialization date + 6 days. 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
tmax00Zbilinear30d24 1 QC1.92 [1.47, 2.33]1.89+0.13 [-0.57, 0.80]2.35 [1.75, 2.81]29% [12%, 46%]62%88%+0.48+0.482026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC1.92 [1.45, 2.36]1.89+0.13 [-0.61, 0.87]2.35 [1.69, 2.87]29% [8%, 48%]62%88%+0.48+0.482026-08-07 → 2026-08-30
tmax00Zbilinear365d24 1 QC1.92 [1.42, 2.40]1.89+0.13 [-0.71, 0.97]2.35 [1.65, 2.92]29% [8%, 50%]62%88%+0.48+0.482026-08-07 → 2026-08-30
tmax00Zbilinearall24 1 QC1.92 [1.41, 2.40]1.89+0.13 [-0.66, 0.97]2.35 [1.64, 2.88]29% [8%, 50%]62%88%+0.48+0.482026-08-07 → 2026-08-30
tmax00Znearest30d24 1 QC2.03 [1.63, 2.41]1.92+0.45 [-0.27, 1.16]2.42 [1.90, 2.84]25% [8%, 43%]50%83%+0.45+0.472026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC2.03 [1.60, 2.41]1.92+0.45 [-0.30, 1.26]2.42 [1.85, 2.88]25% [0%, 46%]50%83%+0.45+0.472026-08-07 → 2026-08-30
tmax00Znearest365d24 1 QC2.03 [1.59, 2.47]1.92+0.45 [-0.43, 1.36]2.42 [1.83, 2.92]25% [0%, 47%]50%83%+0.45+0.472026-08-07 → 2026-08-30
tmax00Znearestall24 1 QC2.03 [1.57, 2.45]1.92+0.45 [-0.37, 1.32]2.42 [1.79, 2.90]25% [0%, 50%]50%83%+0.45+0.472026-08-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC2.50 [1.93, 3.17]2.41+0.30 [-0.51, 1.13]3.19 [2.16, 4.15]17% [0%, 32%]54%67%+0.32+0.342026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC2.50 [1.90, 3.21]2.41+0.30 [-0.62, 1.24]3.19 [2.13, 4.22]17% [0%, 33%]54%67%+0.32+0.342026-08-07 → 2026-08-30
tmax12Zbilinear365d24 1 QC2.50 [1.91, 3.29]2.41+0.30 [-0.71, 1.31]3.19 [2.13, 4.32]17% [0%, 33%]54%67%+0.32+0.342026-08-07 → 2026-08-30
tmax12Zbilinearall24 1 QC2.50 [1.92, 3.13]2.41+0.30 [-0.46, 1.25]3.19 [2.15, 4.24]17% [0%, 33%]54%67%+0.32+0.342026-08-07 → 2026-08-30
tmax12Znearest30d24 1 QC2.60 [2.03, 3.23]2.40+0.61 [-0.19, 1.42]3.21 [2.26, 4.10]8% [0%, 17%]50%71%+0.29+0.342026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC2.60 [2.01, 3.26]2.40+0.61 [-0.30, 1.51]3.21 [2.22, 4.18]8% [0%, 18%]50%71%+0.29+0.342026-08-07 → 2026-08-30
tmax12Znearest365d24 1 QC2.60 [2.03, 3.33]2.40+0.61 [-0.39, 1.59]3.21 [2.22, 4.24]8% [0%, 17%]50%71%+0.29+0.342026-08-07 → 2026-08-30
tmax12Znearestall24 1 QC2.60 [2.02, 3.21]2.40+0.61 [-0.16, 1.54]3.21 [2.22, 4.20]8% [0%, 17%]50%71%+0.29+0.342026-08-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC4.12 [3.06, 5.24]2.33+3.86 [2.51, 5.20]4.79 [3.83, 5.66]12% [0%, 29%]25%38%-0.15+0.312026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC4.12 [3.10, 5.55]2.33+3.86 [2.57, 5.55]4.79 [3.82, 5.84]12% [0%, 29%]25%38%-0.15+0.312026-08-07 → 2026-08-30
tmin00Zbilinear365d24 1 QC4.12 [2.96, 5.42]2.33+3.86 [2.38, 5.40]4.79 [3.75, 5.78]12% [0%, 32%]25%38%-0.15+0.312026-08-07 → 2026-08-30
tmin00Zbilinearall24 1 QC4.12 [2.94, 5.55]2.33+3.86 [2.41, 5.55]4.79 [3.70, 5.93]12% [0%, 30%]25%38%-0.15+0.312026-08-07 → 2026-08-30
tmin00Znearest30d24 1 QC4.31 [3.20, 5.48]2.32+4.13 [2.80, 5.46]5.00 [4.00, 5.90]17% [0%, 40%]25%33%-0.20+0.312026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC4.31 [3.24, 5.80]2.32+4.13 [2.86, 5.80]5.00 [3.99, 6.08]17% [0%, 39%]25%33%-0.20+0.312026-08-07 → 2026-08-30
tmin00Znearest365d24 1 QC4.31 [3.08, 5.67]2.32+4.13 [2.69, 5.67]5.00 [3.91, 6.03]17% [0%, 43%]25%33%-0.20+0.312026-08-07 → 2026-08-30
tmin00Znearestall24 1 QC4.31 [3.10, 5.82]2.32+4.13 [2.70, 5.82]5.00 [3.88, 6.17]17% [0%, 42%]25%33%-0.20+0.312026-08-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC4.03 [2.95, 5.29]2.72+3.76 [2.35, 5.26]4.86 [3.87, 5.79]17% [4%, 30%]38%38%-0.12+0.192026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC4.03 [2.99, 5.62]2.72+3.76 [2.46, 5.61]4.86 [3.90, 5.98]17% [0%, 30%]38%38%-0.12+0.192026-08-07 → 2026-08-30
tmin12Zbilinear365d24 1 QC4.03 [2.80, 5.42]2.72+3.76 [2.18, 5.42]4.86 [3.71, 5.97]17% [0%, 30%]38%38%-0.12+0.192026-08-07 → 2026-08-30
tmin12Zbilinearall24 1 QC4.03 [2.89, 5.66]2.72+3.76 [2.24, 5.66]4.86 [3.76, 6.20]17% [0%, 30%]38%38%-0.12+0.192026-08-07 → 2026-08-30
tmin12Znearest30d24 1 QC4.24 [3.12, 5.54]2.72+4.03 [2.64, 5.51]5.06 [4.04, 6.03]12% [4%, 20%]38%38%-0.18+0.192026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC4.24 [3.16, 5.85]2.72+4.03 [2.75, 5.84]5.06 [4.06, 6.22]12% [0%, 20%]38%38%-0.18+0.192026-08-07 → 2026-08-30
tmin12Znearest365d24 1 QC4.24 [2.98, 5.67]2.72+4.03 [2.49, 5.67]5.06 [3.88, 6.19]12% [0%, 19%]38%38%-0.18+0.192026-08-07 → 2026-08-30
tmin12Znearestall24 1 QC4.24 [3.03, 5.90]2.72+4.03 [2.53, 5.90]5.06 [3.93, 6.43]12% [0%, 19%]38%38%-0.18+0.192026-08-07 → 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 6, 00Z bilinear tmax+10+50-5-102026-08-07: -2.81 °F2026-08-08: +1.72 °F2026-08-09: +1.45 °F2026-08-10: +2.99 °F2026-08-11: +1.72 °F2026-08-12: -1.01 °F2026-08-13: +0.57 °F2026-08-14: +1.64 °F2026-08-15: -0.58 °F2026-08-16: +0.28 °F2026-08-17: +2.48 °F2026-08-18: -2.55 °F2026-08-19: -1.49 °F2026-08-20: +0.94 °F2026-08-21: -6.11 °F2026-08-22: +2.2 °F2026-08-23: +1.31 °F2026-08-24: -1.85 °F2026-08-25: +2.15 °F2026-08-26: +0.79 °F2026-08-27: -4.43 °F2026-08-28: -0.66 °F2026-08-29: +3.73 °F2026-08-30: +0.6 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+0.60
2026-08-29+3.73
2026-08-28-0.66
2026-08-27-4.43
2026-08-26+0.79
2026-08-25+2.15
2026-08-24-1.85
2026-08-23+1.31
2026-08-22+2.20
2026-08-21-6.11
2026-08-20+0.94
2026-08-19-1.49
2026-08-18-2.55
2026-08-17+2.48
2026-08-16+0.28
2026-08-15-0.58
2026-08-14+1.64
2026-08-13+0.57
2026-08-12-1.01
2026-08-11+1.72
2026-08-10+2.99
2026-08-09+1.45
2026-08-08+1.72
2026-08-07-2.81

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, lead day 6-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 1 day-6 to -5 °F: 0 days-5 to -4 °F: 1 day-4 to -3 °F: 0 days-3 to -2 °F: 2 days-2 to -1 °F: 3 days-1 to 0 °F: 2 days0 to 1 °F: 5 days1 to 2 °F: 5 days2 to 3 °F: 4 days3 to 4 °F: 1 day4 to 5 °F: 0 days5 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| 1.68 · P90 |e| 3.51 °F-100+10 °Fn = 24 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
-7.00-6.001
-6.00-5.000
-5.00-4.001
-4.00-3.000
-3.00-2.002
-2.00-1.003
-1.00+0.002
+0.00+1.005
+1.00+2.005
+2.00+3.004
+3.00+4.001
+4.00+5.000
+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
2026-08241.92 +0.13

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24

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
NCEP GFS 24 -1.78 [-2.53, -0.73] yes
GraphCast (IFS init) 24 -0.33 [-0.98, 0.32] no
ECMWF IFS HRES 19 -2.22 [-4.35, -0.49] yes
Persistence (baseline) 24 -1.75 [-3.00, -0.51] yes

Cite this page

ShortCastCheck, KTTN aifs_single lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KTTN/model/aifs_single/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model aifs_single, lead day 6. 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/6/

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

JSON CSV all scores methodology v0.2 licence