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

Trenton Mercer · ECMWF AIFS Single · lead day 5

KTTN · aifs_single · lead 5

Target day = initialization date + 5 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
tmax00Zbilinear30d25 1 QC1.68 [1.30, 2.02]1.71+0.41 [-0.05, 0.91]2.13 [1.78, 2.40]36% [23%, 55%]56%84%+0.55+0.542026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC1.68 [1.24, 2.05]1.71+0.41 [-0.06, 0.98]2.13 [1.73, 2.43]36% [23%, 60%]56%84%+0.55+0.542026-08-06 → 2026-08-30
tmax00Zbilinear365d25 1 QC1.68 [1.25, 2.09]1.71+0.41 [-0.10, 0.98]2.13 [1.72, 2.47]36% [21%, 59%]56%84%+0.55+0.542026-08-06 → 2026-08-30
tmax00Zbilinearall25 1 QC1.68 [1.22, 2.09]1.71+0.41 [-0.08, 0.98]2.13 [1.72, 2.46]36% [21%, 60%]56%84%+0.55+0.542026-08-06 → 2026-08-30
tmax00Znearest30d25 1 QC1.79 [1.37, 2.14]1.72+0.72 [0.26, 1.21]2.23 [1.83, 2.54]36% [23%, 55%]56%84%+0.52+0.542026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC1.79 [1.33, 2.16]1.72+0.72 [0.25, 1.28]2.23 [1.77, 2.56]36% [23%, 60%]56%84%+0.52+0.542026-08-06 → 2026-08-30
tmax00Znearest365d25 1 QC1.79 [1.32, 2.19]1.72+0.72 [0.21, 1.29]2.23 [1.78, 2.61]36% [21%, 59%]56%84%+0.52+0.542026-08-06 → 2026-08-30
tmax00Znearestall25 1 QC1.79 [1.29, 2.20]1.72+0.72 [0.24, 1.27]2.23 [1.75, 2.58]36% [21%, 60%]56%84%+0.52+0.542026-08-06 → 2026-08-30
tmax12Zbilinear30d24 1 QC1.83 [1.40, 2.25]1.80+0.35 [-0.36, 1.01]2.23 [1.71, 2.66]33% [22%, 45%]62%79%+0.51+0.512026-08-06 → 2026-08-30
tmax12Zbilinear90d24 1 QC1.83 [1.37, 2.32]1.80+0.35 [-0.44, 1.11]2.23 [1.59, 2.70]33% [21%, 47%]62%79%+0.51+0.512026-08-06 → 2026-08-30
tmax12Zbilinear365d24 1 QC1.83 [1.35, 2.33]1.80+0.35 [-0.46, 1.22]2.23 [1.56, 2.70]33% [20%, 50%]62%79%+0.51+0.512026-08-06 → 2026-08-30
tmax12Zbilinearall24 1 QC1.83 [1.39, 2.29]1.80+0.35 [-0.45, 1.22]2.23 [1.62, 2.66]33% [20%, 46%]62%79%+0.51+0.512026-08-06 → 2026-08-30
tmax12Znearest30d24 1 QC1.88 [1.40, 2.37]1.82+0.65 [-0.04, 1.29]2.31 [1.73, 2.78]38% [23%, 56%]54%79%+0.49+0.502026-08-06 → 2026-08-30
tmax12Znearest90d24 1 QC1.88 [1.33, 2.43]1.82+0.65 [-0.12, 1.40]2.31 [1.53, 2.81]38% [22%, 60%]54%79%+0.49+0.502026-08-06 → 2026-08-30
tmax12Znearest365d24 1 QC1.88 [1.35, 2.47]1.82+0.65 [-0.12, 1.47]2.31 [1.51, 2.83]38% [20%, 60%]54%79%+0.49+0.502026-08-06 → 2026-08-30
tmax12Znearestall24 1 QC1.88 [1.33, 2.41]1.82+0.65 [-0.14, 1.43]2.31 [1.53, 2.77]38% [21%, 58%]54%79%+0.49+0.502026-08-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC4.21 [3.22, 5.18]2.75+3.92 [2.65, 5.16]5.03 [4.20, 5.83]16% [0%, 31%]20%40%-0.38+0.012026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC4.21 [3.26, 5.24]2.75+3.92 [2.59, 5.20]5.03 [4.20, 5.88]16% [0%, 31%]20%40%-0.38+0.012026-08-06 → 2026-08-30
tmin00Zbilinear365d25 1 QC4.21 [3.05, 5.37]2.75+3.92 [2.41, 5.35]5.03 [4.09, 6.04]16% [0%, 32%]20%40%-0.38+0.012026-08-06 → 2026-08-30
tmin00Zbilinearall25 1 QC4.21 [3.13, 5.46]2.75+3.92 [2.42, 5.46]5.03 [4.08, 6.04]16% [0%, 31%]20%40%-0.38+0.012026-08-06 → 2026-08-30
tmin00Znearest30d25 1 QC4.40 [3.35, 5.43]2.75+4.18 [2.95, 5.41]5.24 [4.37, 6.06]16% [0%, 31%]20%44%-0.45+0.012026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC4.40 [3.38, 5.48]2.75+4.18 [2.88, 5.45]5.24 [4.38, 6.11]16% [0%, 31%]20%44%-0.45+0.012026-08-06 → 2026-08-30
tmin00Znearest365d25 1 QC4.40 [3.18, 5.62]2.75+4.18 [2.70, 5.60]5.24 [4.24, 6.29]16% [0%, 32%]20%44%-0.45+0.012026-08-06 → 2026-08-30
tmin00Znearestall25 1 QC4.40 [3.27, 5.70]2.75+4.18 [2.70, 5.70]5.24 [4.23, 6.29]16% [0%, 31%]20%44%-0.45+0.012026-08-06 → 2026-08-30
tmin12Zbilinear30d24 1 QC3.87 [2.83, 4.84]2.48+3.72 [2.47, 4.83]4.68 [3.63, 5.56]17% [0%, 32%]42%46%-0.24+0.122026-08-06 → 2026-08-30
tmin12Zbilinear90d24 1 QC3.87 [2.82, 4.93]2.48+3.72 [2.47, 4.93]4.68 [3.53, 5.59]17% [0%, 33%]42%46%-0.24+0.122026-08-06 → 2026-08-30
tmin12Zbilinear365d24 1 QC3.87 [2.70, 5.14]2.48+3.72 [2.35, 5.08]4.68 [3.46, 5.79]17% [0%, 33%]42%46%-0.24+0.122026-08-06 → 2026-08-30
tmin12Zbilinearall24 1 QC3.87 [2.73, 5.15]2.48+3.72 [2.32, 5.15]4.68 [3.45, 5.81]17% [0%, 33%]42%46%-0.24+0.122026-08-06 → 2026-08-30
tmin12Znearest30d24 1 QC4.10 [3.02, 5.10]2.48+3.98 [2.76, 5.07]4.90 [3.81, 5.79]8% [0%, 16%]29%42%-0.31+0.122026-08-06 → 2026-08-30
tmin12Znearest90d24 1 QC4.10 [3.02, 5.19]2.48+3.98 [2.76, 5.19]4.90 [3.73, 5.81]8% [0%, 16%]29%42%-0.31+0.122026-08-06 → 2026-08-30
tmin12Znearest365d24 1 QC4.10 [2.87, 5.43]2.48+3.98 [2.64, 5.37]4.90 [3.64, 6.03]8% [0%, 15%]29%42%-0.31+0.122026-08-06 → 2026-08-30
tmin12Znearestall24 1 QC4.10 [2.91, 5.43]2.48+3.98 [2.60, 5.43]4.90 [3.62, 6.06]8% [0%, 17%]29%42%-0.31+0.122026-08-06 → 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 5, 00Z bilinear tmax+5+2.50-2.5-52026-08-06: -0.61 °F2026-08-07: +0.05 °F2026-08-08: -2.33 °F2026-08-09: +0.12 °F2026-08-10: +3.85 °F2026-08-11: +1.47 °F2026-08-12: -2.16 °F2026-08-13: +1.82 °F2026-08-14: -0.23 °F2026-08-15: -2.8 °F2026-08-16: +2.12 °F2026-08-17: +3.8 °F2026-08-18: -2.74 °F2026-08-19: -0.18 °F2026-08-20: -0.19 °F2026-08-21: +2.58 °F2026-08-22: +3.43 °F2026-08-23: -1.59 °F2026-08-24: +0.12 °F2026-08-25: +1.26 °F2026-08-26: +1.05 °F2026-08-27: -2.98 °F2026-08-28: -0.12 °F2026-08-29: +0.55 °F2026-08-30: +3.91 °F2026-08-062026-08-30°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 (25 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+3.91
2026-08-29+0.55
2026-08-28-0.12
2026-08-27-2.98
2026-08-26+1.05
2026-08-25+1.26
2026-08-24+0.12
2026-08-23-1.59
2026-08-22+3.43
2026-08-21+2.58
2026-08-20-0.19
2026-08-19-0.18
2026-08-18-2.74
2026-08-17+3.80
2026-08-16+2.12
2026-08-15-2.80
2026-08-14-0.23
2026-08-13+1.82
2026-08-12-2.16
2026-08-11+1.47
2026-08-10+3.85
2026-08-09+0.12
2026-08-08-2.33
2026-08-07+0.05
2026-08-06-0.61

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KTTN, lead day 5-5 to -4.5 °F: 0 days-4.5 to -4 °F: 0 days-4 to -3.5 °F: 0 days-3.5 to -3 °F: 0 days-3 to -2.5 °F: 3 days-2.5 to -2 °F: 2 days-2 to -1.5 °F: 1 day-1.5 to -1 °F: 0 days-1 to -0.5 °F: 1 day-0.5 to 0 °F: 4 days0 to 0.5 °F: 3 days0.5 to 1 °F: 1 day1 to 1.5 °F: 3 days1.5 to 2 °F: 1 day2 to 2.5 °F: 1 day2.5 to 3 °F: 1 day3 to 3.5 °F: 1 day3.5 to 4 °F: 3 days4 to 4.5 °F: 0 days4.5 to 5 °F: 0 daysdashed: P50 |e| 1.59 · P90 |e| 3.65 °F-50+5 °Fn = 25 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
-5.00-4.500
-4.50-4.000
-4.00-3.500
-3.50-3.000
-3.00-2.503
-2.50-2.002
-2.00-1.501
-1.50-1.000
-1.00-0.501
-0.50+0.004
+0.00+0.503
+0.50+1.001
+1.00+1.503
+1.50+2.001
+2.00+2.501
+2.50+3.001
+3.00+3.501
+3.50+4.003
+4.00+4.500
+4.50+5.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08251.68 +0.41

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-06 → 2026-08-30 25
ECMWF AIFS Single2026-08-06 → 2026-08-30 25
ECMWF AIFS Single2026-08-06 → 2026-08-30 24
ECMWF AIFS Single2026-08-06 → 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 25 -2.59 [-4.06, -0.96] yes
GraphCast (IFS init) 25 -0.65 [-1.85, 0.07] no
ECMWF IFS HRES 18 -1.45 [-3.23, -0.41] yes
Persistence (baseline) 25 -2.08 [-3.34, -0.76] yes

Cite this page

ShortCastCheck, KTTN aifs_single lead 5, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KTTN/model/aifs_single/lead/5/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model aifs_single, lead day 5. 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/5/

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