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

Trenton Mercer · ECMWF IFS HRES · lead day 4

KTTN · ifs_hres · lead 4

Target day = initialization date + 4 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, ifs-gpid161, 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
tmax00Zbilinear30d20 1 QC3.42 [2.78, 4.28]3.37+0.52 [-1.34, 2.93]4.16 [3.17, 5.13]15% [0%, 38%]30%50%+0.01-0.112026-08-05 → 2026-08-30
tmax00Zbilinear90d20 1 QC3.42 [2.74, 4.32]3.37+0.52 [-1.65, 3.03]4.16 [3.13, 5.14]15% [0%, 38%]30%50%+0.01-0.112026-08-05 → 2026-08-30
tmax00Zbilinear365d20 1 QC3.42 [2.69, 4.38]3.37+0.52 [-1.66, 3.16]4.16 [3.05, 5.25]15% [0%, 42%]30%50%+0.01-0.112026-08-05 → 2026-08-30
tmax00Zbilinearall20 1 QC3.42 [2.76, 4.34]3.37+0.52 [-1.80, 3.08]4.16 [3.08, 5.17]15% [0%, 40%]30%50%+0.01-0.112026-08-05 → 2026-08-30
tmax00Znearest30d20 1 QC3.50 [2.75, 4.46]3.45+0.69 [-1.28, 3.25]4.26 [3.09, 5.31]10% [0%, 23%]30%45%-0.01-0.142026-08-05 → 2026-08-30
tmax00Znearest90d20 1 QC3.50 [2.74, 4.50]3.45+0.69 [-1.61, 3.31]4.26 [3.03, 5.33]10% [0%, 23%]30%45%-0.01-0.142026-08-05 → 2026-08-30
tmax00Znearest365d20 1 QC3.50 [2.65, 4.60]3.45+0.69 [-1.60, 3.45]4.26 [2.94, 5.44]10% [0%, 25%]30%45%-0.01-0.142026-08-05 → 2026-08-30
tmax00Znearestall20 1 QC3.50 [2.69, 4.55]3.45+0.69 [-1.84, 3.40]4.26 [2.99, 5.37]10% [0%, 24%]30%45%-0.01-0.142026-08-05 → 2026-08-30
tmax12Zbilinear30d21 1 QC2.41 [1.32, 3.52]2.42+0.03 [-1.18, 1.22]3.28 [1.69, 4.52]33% [20%, 50%]52%71%+0.27+0.192026-08-05 → 2026-08-30
tmax12Zbilinear90d21 1 QC2.41 [1.10, 3.47]2.42+0.03 [-1.17, 1.38]3.28 [1.52, 4.54]33% [20%, 57%]52%71%+0.27+0.192026-08-05 → 2026-08-30
tmax12Zbilinear365d21 1 QC2.41 [1.12, 3.60]2.42+0.03 [-1.24, 1.38]3.28 [1.32, 4.64]33% [17%, 56%]52%71%+0.27+0.192026-08-05 → 2026-08-30
tmax12Zbilinearall21 1 QC2.41 [1.15, 3.56]2.42+0.03 [-1.35, 1.45]3.28 [1.32, 4.61]33% [18%, 57%]52%71%+0.27+0.192026-08-05 → 2026-08-30
tmax12Znearest30d21 1 QC2.59 [1.53, 3.67]2.62+0.12 [-1.24, 1.54]3.50 [1.91, 4.79]33% [20%, 54%]52%67%+0.21+0.132026-08-05 → 2026-08-30
tmax12Znearest90d21 1 QC2.59 [1.33, 3.63]2.62+0.12 [-1.23, 1.77]3.50 [1.77, 4.77]33% [19%, 62%]52%67%+0.21+0.132026-08-05 → 2026-08-30
tmax12Znearest365d21 1 QC2.59 [1.33, 3.77]2.62+0.12 [-1.31, 1.78]3.50 [1.81, 4.90]33% [18%, 60%]52%67%+0.21+0.132026-08-05 → 2026-08-30
tmax12Znearestall21 1 QC2.59 [1.33, 3.73]2.62+0.12 [-1.43, 1.77]3.50 [1.77, 4.88]33% [19%, 60%]52%67%+0.21+0.132026-08-05 → 2026-08-30
tmin00Zbilinear30d20 1 QC5.05 [4.07, 5.86]2.23+4.94 [3.81, 5.84]5.59 [4.75, 6.26]5% [0%, 14%]15%25%-0.63+0.262026-08-05 → 2026-08-30
tmin00Zbilinear90d20 1 QC5.05 [3.85, 6.10]2.23+4.94 [3.76, 6.10]5.59 [4.35, 6.51]5% [0%, 14%]15%25%-0.63+0.262026-08-05 → 2026-08-30
tmin00Zbilinear365d20 1 QC5.05 [3.85, 6.09]2.23+4.94 [3.67, 6.09]5.59 [4.37, 6.50]5% [0%, 14%]15%25%-0.63+0.262026-08-05 → 2026-08-30
tmin00Zbilinearall20 1 QC5.05 [3.85, 6.02]2.23+4.94 [3.75, 6.02]5.59 [4.36, 6.44]5% [0%, 14%]15%25%-0.63+0.262026-08-05 → 2026-08-30
tmin00Znearest30d20 1 QC5.28 [4.30, 6.09]2.27+5.21 [4.10, 6.09]5.84 [4.99, 6.49]5% [0%, 15%]15%25%-0.70+0.252026-08-05 → 2026-08-30
tmin00Znearest90d20 1 QC5.28 [3.96, 6.33]2.27+5.21 [3.84, 6.33]5.84 [4.57, 6.77]5% [0%, 17%]15%25%-0.70+0.252026-08-05 → 2026-08-30
tmin00Znearest365d20 1 QC5.28 [3.99, 6.34]2.27+5.21 [3.91, 6.33]5.84 [4.61, 6.76]5% [0%, 18%]15%25%-0.70+0.252026-08-05 → 2026-08-30
tmin00Znearestall20 1 QC5.28 [3.98, 6.27]2.27+5.21 [3.84, 6.27]5.84 [4.61, 6.68]5% [0%, 18%]15%25%-0.70+0.252026-08-05 → 2026-08-30
tmin12Zbilinear30d21 1 QC4.28 [2.93, 5.53]2.80+4.11 [2.62, 5.38]5.30 [3.87, 6.67]19% [0%, 44%]33%38%-0.36+0.072026-08-05 → 2026-08-30
tmin12Zbilinear90d21 1 QC4.28 [2.26, 5.96]2.80+4.11 [1.64, 5.82]5.30 [2.91, 7.25]19% [0%, 44%]33%38%-0.36+0.072026-08-05 → 2026-08-30
tmin12Zbilinear365d21 1 QC4.28 [2.31, 6.31]2.80+4.11 [1.57, 5.85]5.30 [2.95, 7.38]19% [0%, 50%]33%38%-0.36+0.072026-08-05 → 2026-08-30
tmin12Zbilinearall21 1 QC4.28 [2.21, 6.29]2.80+4.11 [1.77, 5.95]5.30 [2.91, 7.47]19% [0%, 48%]33%38%-0.36+0.072026-08-05 → 2026-08-30
tmin12Znearest30d21 1 QC4.45 [3.04, 5.65]2.80+4.35 [2.87, 5.56]5.46 [3.95, 6.76]19% [4%, 42%]33%38%-0.42+0.072026-08-05 → 2026-08-30
tmin12Znearest90d21 1 QC4.45 [2.22, 6.11]2.80+4.35 [1.83, 5.97]5.46 [2.80, 7.33]19% [0%, 50%]33%38%-0.42+0.072026-08-05 → 2026-08-30
tmin12Znearest365d21 1 QC4.45 [2.24, 6.34]2.80+4.35 [1.81, 6.03]5.46 [2.87, 7.44]19% [0%, 50%]33%38%-0.42+0.072026-08-05 → 2026-08-30
tmin12Znearestall21 1 QC4.45 [2.22, 6.34]2.80+4.35 [1.89, 6.11]5.46 [2.86, 7.56]19% [0%, 50%]33%38%-0.42+0.072026-08-05 → 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 IFS HRES at KTTN, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -3.72 °F2026-08-11: +5.58 °F2026-08-12: +0.49 °F2026-08-13: +0.98 °F2026-08-14: +6.05 °F2026-08-16: +9.11 °F2026-08-17: +2.04 °F2026-08-18: -0.85 °F2026-08-19: +5.01 °F2026-08-20: -8.23 °F2026-08-21: +1.31 °F2026-08-22: -3.21 °F2026-08-23: -1.1 °F2026-08-24: -1.49 °F2026-08-25: +2.28 °F2026-08-26: -2.1 °F2026-08-27: -5.23 °F2026-08-28: -3.1 °F2026-08-29: +3.5 °F2026-08-30: +2.98 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+2.98
2026-08-29+3.50
2026-08-28-3.10
2026-08-27-5.23
2026-08-26-2.10
2026-08-25+2.28
2026-08-24-1.49
2026-08-23-1.10
2026-08-22-3.21
2026-08-21+1.31
2026-08-20-8.23
2026-08-19+5.01
2026-08-18-0.85
2026-08-17+2.04
2026-08-16+9.11
2026-08-15—
2026-08-14+6.05
2026-08-13+0.98
2026-08-12+0.49
2026-08-11+5.58
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05-3.72

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KTTN, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 1 day-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: 3 days-3 to -2 °F: 1 day-2 to -1 °F: 2 days-1 to 0 °F: 1 day0 to 1 °F: 2 days1 to 2 °F: 1 day2 to 3 °F: 3 days3 to 4 °F: 1 day4 to 5 °F: 0 days5 to 6 °F: 2 days6 to 7 °F: 1 day7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 1 daydashed: P50 |e| 3.04 · P90 |e| 6.27 °F-100+10 °Fn = 20 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
-9.00-8.001
-8.00-7.000
-7.00-6.000
-6.00-5.001
-5.00-4.000
-4.00-3.003
-3.00-2.001
-2.00-1.002
-1.00+0.001
+0.00+1.002
+1.00+2.001
+2.00+3.003
+3.00+4.001
+4.00+5.000
+5.00+6.002
+6.00+7.001
+7.00+8.000
+8.00+9.000
+9.00+10.001

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08203.42 +0.52

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-05 → 2026-08-30 20
ECMWF IFS HRES2026-08-05 → 2026-08-30 20
ECMWF IFS HRES2026-08-05 → 2026-08-30 21
ECMWF IFS HRES2026-08-05 → 2026-08-30 21

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 20 +1.78 [0.55, 2.70] yes
NCEP GFS 20 +0.17 [-1.12, 1.12] no
GraphCast (IFS init) 19 +1.41 [0.59, 2.86] yes
Persistence (baseline) 20 -0.03 [-1.52, 1.55] no

Cite this page

ShortCastCheck, KTTN ifs_hres lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KTTN/model/ifs_hres/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model ifs_hres, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KTTN/model/ifs_hres/lead/4/

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