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

Denver Intl · ECMWF AIFS Single · lead day 4

KDEN · aifs_single · 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, 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
tmax00Zbilinear30d26 1 QC4.26 [3.13, 5.29]2.26-4.06 [-5.06, -2.91]5.07 [3.57, 6.09]8% [0%, 15%]19%38%+0.45+0.712026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC4.26 [2.90, 5.27]2.26-4.06 [-5.06, -2.66]5.07 [3.29, 6.14]8% [0%, 14%]19%38%+0.45+0.712026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC4.26 [2.92, 5.37]2.26-4.06 [-5.09, -2.72]5.07 [3.29, 6.20]8% [0%, 15%]19%38%+0.45+0.712026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC4.26 [2.87, 5.33]2.26-4.06 [-5.16, -2.60]5.07 [3.26, 6.18]8% [0%, 15%]19%38%+0.45+0.712026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC4.37 [3.23, 5.38]2.28-4.17 [-5.13, -3.01]5.15 [3.64, 6.17]4% [0%, 11%]19%35%+0.43+0.702026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC4.37 [2.99, 5.35]2.28-4.17 [-5.15, -2.79]5.15 [3.35, 6.21]4% [0%, 11%]19%35%+0.43+0.702026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC4.37 [3.02, 5.42]2.28-4.17 [-5.20, -2.87]5.15 [3.40, 6.24]4% [0%, 13%]19%35%+0.43+0.702026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC4.37 [2.94, 5.42]2.28-4.17 [-5.25, -2.61]5.15 [3.34, 6.23]4% [0%, 13%]19%35%+0.43+0.702026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC4.10 [3.06, 5.22]2.36-3.87 [-5.07, -2.76]4.86 [3.64, 5.93]8% [0%, 20%]27%38%+0.47+0.692026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC4.10 [2.83, 5.20]2.36-3.87 [-5.07, -2.51]4.86 [3.41, 5.97]8% [0%, 22%]27%38%+0.47+0.692026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC4.10 [2.74, 5.29]2.36-3.87 [-5.13, -2.44]4.86 [3.32, 6.04]8% [0%, 25%]27%38%+0.47+0.692026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC4.10 [2.72, 5.33]2.36-3.87 [-5.16, -2.35]4.86 [3.30, 6.06]8% [0%, 25%]27%38%+0.47+0.692026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC4.16 [3.08, 5.30]2.32-3.93 [-5.11, -2.83]4.90 [3.64, 6.00]8% [0%, 20%]27%38%+0.46+0.702026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC4.16 [2.87, 5.31]2.32-3.93 [-5.15, -2.60]4.90 [3.42, 6.06]8% [0%, 22%]27%38%+0.46+0.702026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC4.16 [2.72, 5.37]2.32-3.93 [-5.21, -2.57]4.90 [3.35, 6.14]8% [0%, 25%]27%38%+0.46+0.702026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC4.16 [2.67, 5.41]2.32-3.93 [-5.22, -2.44]4.90 [3.32, 6.14]8% [0%, 25%]27%38%+0.46+0.702026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC2.95 [2.28, 3.99]2.43+2.24 [1.00, 3.77]3.90 [2.81, 5.54]27% [8%, 45%]46%46%+0.50+0.592026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC2.95 [2.31, 4.15]2.43+2.24 [1.00, 3.94]3.90 [2.83, 5.97]27% [8%, 48%]46%46%+0.50+0.592026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC2.95 [2.25, 4.15]2.43+2.24 [0.87, 3.89]3.90 [2.76, 5.62]27% [5%, 48%]46%46%+0.50+0.592026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC2.95 [2.26, 4.29]2.43+2.24 [0.89, 4.23]3.90 [2.79, 6.05]27% [0%, 50%]46%46%+0.50+0.592026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC3.02 [2.36, 4.02]2.41+2.26 [0.94, 3.82]3.91 [2.87, 5.50]15% [3%, 30%]42%46%+0.49+0.592026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC3.02 [2.39, 4.22]2.41+2.26 [0.92, 3.99]3.91 [2.88, 5.91]15% [0%, 31%]42%46%+0.49+0.592026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC3.02 [2.32, 4.19]2.41+2.26 [0.83, 3.94]3.91 [2.80, 5.58]15% [0%, 33%]42%46%+0.49+0.592026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC3.02 [2.37, 4.35]2.41+2.26 [0.83, 4.30]3.91 [2.83, 5.99]15% [0%, 33%]42%46%+0.49+0.592026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC3.07 [2.34, 4.11]2.57+2.33 [0.99, 3.87]4.02 [2.98, 5.58]31% [8%, 55%]38%46%+0.48+0.562026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC3.07 [2.36, 4.36]2.57+2.33 [0.95, 4.15]4.02 [2.98, 5.89]31% [8%, 57%]38%46%+0.48+0.562026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC3.07 [2.27, 4.36]2.57+2.33 [0.81, 4.12]4.02 [2.89, 5.58]31% [5%, 57%]38%46%+0.48+0.562026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC3.07 [2.31, 4.37]2.57+2.33 [0.81, 4.32]4.02 [2.92, 6.08]31% [0%, 58%]38%46%+0.48+0.562026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC3.20 [2.50, 4.19]2.56+2.37 [0.95, 3.93]4.07 [3.06, 5.57]27% [8%, 45%]38%50%+0.46+0.572026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC3.20 [2.51, 4.43]2.56+2.37 [0.91, 4.25]4.07 [3.07, 5.86]27% [8%, 48%]38%50%+0.46+0.572026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC3.20 [2.42, 4.40]2.56+2.37 [0.75, 4.17]4.07 [2.98, 5.58]27% [5%, 48%]38%50%+0.46+0.572026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC3.20 [2.44, 4.56]2.56+2.37 [0.75, 4.39]4.07 [2.99, 6.06]27% [0%, 50%]38%50%+0.46+0.572026-08-05 → 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 AIFS Single at KDEN, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: -2.81 °F2026-08-06: -5.65 °F2026-08-07: +1.14 °F2026-08-08: -2.65 °F2026-08-09: -0.74 °F2026-08-10: -2.49 °F2026-08-11: -7.73 °F2026-08-12: -6.84 °F2026-08-13: -4.99 °F2026-08-14: -10.61 °F2026-08-15: -2.72 °F2026-08-16: -3.88 °F2026-08-17: -4.9 °F2026-08-18: +1.42 °F2026-08-19: -10.86 °F2026-08-20: -4.88 °F2026-08-21: -8.91 °F2026-08-22: -2.75 °F2026-08-23: -3.9 °F2026-08-24: -3.5 °F2026-08-25: -0.17 °F2026-08-26: -3.96 °F2026-08-27: -4.44 °F2026-08-28: -3.38 °F2026-08-29: -4.19 °F2026-08-30: -1.2 °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
2026-08-30-1.20
2026-08-29-4.19
2026-08-28-3.38
2026-08-27-4.44
2026-08-26-3.96
2026-08-25-0.17
2026-08-24-3.50
2026-08-23-3.90
2026-08-22-2.75
2026-08-21-8.91
2026-08-20-4.88
2026-08-19-10.86
2026-08-18+1.42
2026-08-17-4.90
2026-08-16-3.88
2026-08-15-2.72
2026-08-14-10.61
2026-08-13-4.99
2026-08-12-6.84
2026-08-11-7.73
2026-08-10-2.49
2026-08-09-0.74
2026-08-08-2.65
2026-08-07+1.14
2026-08-06-5.65
2026-08-05-2.81

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KDEN, lead day 4-20 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: 2 days-10 to -8 °F: 1 day-8 to -6 °F: 2 days-6 to -4 °F: 6 days-4 to -2 °F: 10 days-2 to 0 °F: 3 days0 to 2 °F: 2 days2 to 4 °F: 0 days4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 3.89 · P90 |e| 8.32 °F-200+20 °Fn = 26 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
-12.00-10.002
-10.00-8.001
-8.00-6.002
-6.00-4.006
-4.00-2.0010
-2.00+0.003
+0.00+2.002
+2.00+4.000
+4.00+6.000
+6.00+8.000
+8.00+10.000
+10.00+12.000
+12.00+14.000
+14.00+16.000
+16.00+18.000
+18.00+20.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08264.26 -4.06

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26

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 26 -0.22 [-2.10, 1.18] no
GraphCast (IFS init) 25 -2.92 [-3.70, -2.07] yes
ECMWF IFS HRES 20 +0.26 [-1.12, 2.87] no
Persistence (baseline) 26 -3.43 [-6.17, -1.27] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model aifs_single, 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/KDEN/model/aifs_single/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