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

Trenton Mercer · ECMWF IFS HRES · lead day 9

KTTN · ifs_hres · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d16 1 QC4.51 [1.64, 7.32]4.80+1.96 [-1.69, 4.05]6.73 [2.81, 8.98]31% [0%, 58%]38%50%-0.05-1.072026-08-10 → 2026-08-30
tmax00Zbilinear90d16 1 QC4.51 [1.43, 7.46]4.80+1.96 [-5.31, 4.07]6.73 [2.34, 9.01]31% [0%, 59%]38%50%-0.05-1.072026-08-10 → 2026-08-30
tmax00Zbilinear365d16 1 QC4.51 [1.27, 7.47]4.80+1.96 [-2.85, 4.27]6.73 [1.59, 9.14]31% [0%, 57%]38%50%-0.05-1.072026-08-10 → 2026-08-30
tmax00Zbilinearall16 1 QC4.51 [1.25, 7.46]4.80+1.96 [-3.18, 4.34]6.73 [1.57, 8.94]31% [0%, 58%]38%50%-0.05-1.072026-08-10 → 2026-08-30
tmax00Znearest30d16 1 QC4.48 [1.58, 7.36]4.74+1.92 [-1.61, 3.88]6.66 [2.69, 8.98]31% [0%, 58%]38%50%-0.04-1.042026-08-10 → 2026-08-30
tmax00Znearest90d16 1 QC4.48 [1.41, 7.56]4.74+1.92 [-5.16, 3.87]6.66 [2.17, 8.98]31% [0%, 59%]38%50%-0.04-1.042026-08-10 → 2026-08-30
tmax00Znearest365d16 1 QC4.48 [1.28, 7.61]4.74+1.92 [-2.81, 4.06]6.66 [1.54, 9.11]31% [0%, 57%]38%50%-0.04-1.042026-08-10 → 2026-08-30
tmax00Znearestall16 1 QC4.48 [1.28, 7.57]4.74+1.92 [-3.09, 4.07]6.66 [1.54, 8.96]31% [0%, 58%]38%50%-0.04-1.042026-08-10 → 2026-08-30
tmax12Zbilinear30d15 1 QC5.16 [3.06, 7.14]4.98-1.28 [-3.31, 1.63]6.69 [3.95, 8.28]27% [6%, 50%]27%33%-0.19-1.022026-08-10 → 2026-08-30
tmax12Zbilinear90d15 1 QC5.16 [1.37, 7.15]4.98-1.28 [-3.24, 1.52]6.69 [2.17, 8.21]27% [0%, 83%]27%33%-0.19-1.022026-08-10 → 2026-08-30
tmax12Zbilinear365d15 1 QC5.16 [1.79, 7.32]4.98-1.28 [-3.25, 1.94]6.69 [2.98, 8.37]27% [0%, 75%]27%33%-0.19-1.022026-08-10 → 2026-08-30
tmax12Zbilinearall15 1 QC5.16 [2.22, 7.32]4.98-1.28 [-3.39, 1.85]6.69 [3.32, 8.35]27% [0%, 75%]27%33%-0.19-1.022026-08-10 → 2026-08-30
tmax12Znearest30d15 1 QC5.04 [2.89, 7.06]4.85-1.24 [-3.27, 1.80]6.59 [3.88, 8.25]20% [0%, 50%]33%33%-0.16-0.962026-08-10 → 2026-08-30
tmax12Znearest90d15 1 QC5.04 [1.08, 7.00]4.85-1.24 [-3.28, 1.71]6.59 [1.99, 8.22]20% [0%, 83%]33%33%-0.16-0.962026-08-10 → 2026-08-30
tmax12Znearest365d15 1 QC5.04 [1.53, 7.23]4.85-1.24 [-3.35, 2.07]6.59 [2.87, 8.23]20% [0%, 75%]33%33%-0.16-0.962026-08-10 → 2026-08-30
tmax12Znearestall15 1 QC5.04 [1.99, 7.15]4.85-1.24 [-3.35, 2.09]6.59 [3.26, 8.38]20% [0%, 75%]33%33%-0.16-0.962026-08-10 → 2026-08-30
tmin00Zbilinear30d16 1 QC6.09 [4.15, 7.64]4.92+5.93 [4.02, 7.56]8.02 [6.11, 9.17]25% [0%, 50%]38%44%-0.32-1.022026-08-10 → 2026-08-30
tmin00Zbilinear90d16 1 QC6.09 [2.60, 7.84]4.92+5.93 [2.60, 7.75]8.02 [4.05, 9.21]25% [0%, 50%]38%44%-0.32-1.022026-08-10 → 2026-08-30
tmin00Zbilinear365d16 1 QC6.09 [2.92, 8.01]4.92+5.93 [2.92, 7.93]8.02 [4.59, 9.24]25% [0%, 53%]38%44%-0.32-1.022026-08-10 → 2026-08-30
tmin00Zbilinearall16 1 QC6.09 [2.91, 8.10]4.92+5.93 [2.91, 8.09]8.02 [5.21, 9.35]25% [0%, 55%]38%44%-0.32-1.022026-08-10 → 2026-08-30
tmin00Znearest30d16 1 QC6.34 [4.43, 7.92]4.85+6.22 [4.39, 7.80]8.20 [6.36, 9.32]25% [0%, 55%]31%44%-0.37-0.992026-08-10 → 2026-08-30
tmin00Znearest90d16 1 QC6.34 [2.98, 8.08]4.85+6.22 [2.98, 8.01]8.20 [4.36, 9.35]25% [0%, 56%]31%44%-0.37-0.992026-08-10 → 2026-08-30
tmin00Znearest365d16 1 QC6.34 [3.27, 8.28]4.85+6.22 [3.27, 8.18]8.20 [4.86, 9.38]25% [0%, 57%]31%44%-0.37-0.992026-08-10 → 2026-08-30
tmin00Znearestall16 1 QC6.34 [3.26, 8.35]4.85+6.22 [3.26, 8.34]8.20 [5.45, 9.50]25% [0%, 59%]31%44%-0.37-0.992026-08-10 → 2026-08-30
tmin12Zbilinear30d15 1 QC4.89 [3.93, 6.15]3.77+4.16 [2.66, 6.10]5.86 [5.01, 6.74]13% [0%, 25%]33%33%-0.11-0.582026-08-10 → 2026-08-30
tmin12Zbilinear90d15 1 QC4.89 [4.04, 6.32]3.77+4.16 [2.69, 6.32]5.86 [5.04, 6.91]13% [0%, 25%]33%33%-0.11-0.582026-08-10 → 2026-08-30
tmin12Zbilinear365d15 1 QC4.89 [3.79, 6.47]3.77+4.16 [2.43, 6.45]5.86 [4.87, 6.91]13% [0%, 25%]33%33%-0.11-0.582026-08-10 → 2026-08-30
tmin12Zbilinearall15 1 QC4.89 [3.98, 6.42]3.77+4.16 [2.58, 6.42]5.86 [4.97, 6.89]13% [0%, 25%]33%33%-0.11-0.582026-08-10 → 2026-08-30
tmin12Znearest30d15 1 QC5.05 [4.03, 6.40]3.81+4.40 [2.90, 6.36]6.05 [5.10, 6.96]13% [0%, 25%]33%40%-0.15-0.602026-08-10 → 2026-08-30
tmin12Znearest90d15 1 QC5.05 [4.16, 6.60]3.81+4.40 [2.92, 6.60]6.05 [5.12, 7.18]13% [0%, 25%]33%40%-0.15-0.602026-08-10 → 2026-08-30
tmin12Znearest365d15 1 QC5.05 [3.93, 6.70]3.81+4.40 [2.65, 6.70]6.05 [5.03, 7.16]13% [0%, 25%]33%40%-0.15-0.602026-08-10 → 2026-08-30
tmin12Znearestall15 1 QC5.05 [4.05, 6.72]3.81+4.40 [2.85, 6.71]6.05 [5.06, 7.16]13% [0%, 25%]33%40%-0.15-0.602026-08-10 → 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 9, 00Z bilinear tmax+20+100-10-202026-08-10: -7.32 °F2026-08-16: +10.74 °F2026-08-17: -5.71 °F2026-08-18: -2.27 °F2026-08-19: -3.9 °F2026-08-20: +6.35 °F2026-08-21: +19.56 °F2026-08-22: -0.28 °F2026-08-23: +3.87 °F2026-08-24: +7.56 °F2026-08-25: -0.52 °F2026-08-26: -0.32 °F2026-08-27: -0.02 °F2026-08-28: -0.07 °F2026-08-29: +2.04 °F2026-08-30: +1.62 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+1.62
2026-08-29+2.04
2026-08-28-0.07
2026-08-27-0.02
2026-08-26-0.32
2026-08-25-0.52
2026-08-24+7.56
2026-08-23+3.87
2026-08-22-0.28
2026-08-21+19.56
2026-08-20+6.35
2026-08-19-3.90
2026-08-18-2.27
2026-08-17-5.71
2026-08-16+10.74
2026-08-15—
2026-08-14—
2026-08-13—
2026-08-12—
2026-08-11—
2026-08-10-7.32

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KTTN, lead day 9-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 0 days-10 to -8 °F: 0 days-8 to -6 °F: 1 day-6 to -4 °F: 1 day-4 to -2 °F: 2 days-2 to 0 °F: 5 days0 to 2 °F: 1 day2 to 4 °F: 2 days4 to 6 °F: 0 days6 to 8 °F: 2 days8 to 10 °F: 0 days10 to 12 °F: 1 day12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 1 daydashed: P50 |e| 3.07 · P90 |e| 9.15 °F-200+20 °Fn = 16 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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.000
-12.00-10.000
-10.00-8.000
-8.00-6.001
-6.00-4.001
-4.00-2.002
-2.00+0.005
+0.00+2.001
+2.00+4.002
+4.00+6.000
+6.00+8.002
+8.00+10.000
+10.00+12.001
+12.00+14.000
+14.00+16.000
+16.00+18.000
+18.00+20.001

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08164.51 +1.96

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-10 → 2026-08-30 16
ECMWF IFS HRES2026-08-10 → 2026-08-30 16
ECMWF IFS HRES2026-08-10 → 2026-08-30 15
ECMWF IFS HRES2026-08-10 → 2026-08-30 15

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 16 +0.52 [-2.18, 5.58] no
NCEP GFS 16 -0.64 [-3.69, 3.62] no
GraphCast (IFS init) 16 +0.24 [-1.86, 6.25] no
Persistence (baseline) 16 +0.20 [-2.07, 5.04] no

Cite this page

ShortCastCheck, KTTN ifs_hres lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KTTN/model/ifs_hres/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KTTN (Trenton Mercer), model ifs_hres, lead day 9. 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/9/

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