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

Atlanta Hartsfield · ECMWF IFS HRES · lead day 4

KATL · 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 QC4.00 [2.41, 5.87]3.94-2.08 [-5.57, 1.07]5.36 [2.99, 7.08]15% [0%, 34%]40%50%-0.54-0.502026-08-05 → 2026-08-30
tmax00Zbilinear90d20 1 QC4.00 [2.11, 6.01]3.94-2.08 [-5.91, 1.41]5.36 [2.59, 7.16]15% [0%, 33%]40%50%-0.54-0.502026-08-05 → 2026-08-30
tmax00Zbilinear365d20 1 QC4.00 [2.10, 5.97]3.94-2.08 [-5.79, 1.59]5.36 [2.59, 7.05]15% [0%, 38%]40%50%-0.54-0.502026-08-05 → 2026-08-30
tmax00Zbilinearall20 1 QC4.00 [2.05, 5.91]3.94-2.08 [-5.73, 1.32]5.36 [2.47, 7.08]15% [0%, 38%]40%50%-0.54-0.502026-08-05 → 2026-08-30
tmax00Znearest30d20 1 QC4.18 [2.75, 5.81]4.00-1.83 [-5.47, 1.46]5.36 [3.38, 6.92]10% [0%, 18%]35%55%-0.61-0.532026-08-05 → 2026-08-30
tmax00Znearest90d20 1 QC4.18 [2.50, 5.94]4.00-1.83 [-5.79, 1.90]5.36 [3.00, 6.96]10% [0%, 18%]35%55%-0.61-0.532026-08-05 → 2026-08-30
tmax00Znearest365d20 1 QC4.18 [2.44, 5.82]4.00-1.83 [-5.70, 1.99]5.36 [2.76, 6.86]10% [0%, 19%]35%55%-0.61-0.532026-08-05 → 2026-08-30
tmax00Znearestall20 1 QC4.18 [2.44, 5.87]4.00-1.83 [-5.60, 1.69]5.36 [2.69, 6.93]10% [0%, 18%]35%55%-0.61-0.532026-08-05 → 2026-08-30
tmax12Zbilinear30d21 1 QC3.24 [2.37, 4.63]3.08-1.86 [-4.27, -0.12]4.22 [2.89, 5.50]19% [7%, 27%]29%57%-0.24-0.172026-08-05 → 2026-08-30
tmax12Zbilinear90d21 1 QC3.24 [2.34, 5.35]3.08-1.86 [-5.35, -0.00]4.22 [2.87, 5.78]19% [0%, 27%]29%57%-0.24-0.172026-08-05 → 2026-08-30
tmax12Zbilinear365d21 1 QC3.24 [2.29, 5.05]3.08-1.86 [-5.05, 0.08]4.22 [2.79, 5.77]19% [0%, 29%]29%57%-0.24-0.172026-08-05 → 2026-08-30
tmax12Zbilinearall21 1 QC3.24 [2.31, 5.21]3.08-1.86 [-5.21, -0.00]4.22 [2.70, 5.78]19% [0%, 27%]29%57%-0.24-0.172026-08-05 → 2026-08-30
tmax12Znearest30d21 1 QC3.30 [2.45, 4.54]3.18-1.54 [-3.96, 0.29]4.21 [2.93, 5.38]19% [7%, 27%]33%57%-0.26-0.212026-08-05 → 2026-08-30
tmax12Znearest90d21 1 QC3.30 [2.40, 5.17]3.18-1.54 [-5.17, 0.36]4.21 [2.82, 5.60]19% [0%, 27%]33%57%-0.26-0.212026-08-05 → 2026-08-30
tmax12Znearest365d21 1 QC3.30 [2.37, 5.07]3.18-1.54 [-5.07, 0.45]4.21 [2.80, 5.62]19% [0%, 29%]33%57%-0.26-0.212026-08-05 → 2026-08-30
tmax12Znearestall21 1 QC3.30 [2.34, 5.18]3.18-1.54 [-5.18, 0.31]4.21 [2.74, 5.64]19% [0%, 27%]33%57%-0.26-0.212026-08-05 → 2026-08-30
tmin00Zbilinear30d20 1 QC2.44 [1.68, 3.02]2.47+0.50 [-0.96, 2.18]2.96 [2.00, 3.52]20% [5%, 40%]45%75%-0.09-0.082026-08-05 → 2026-08-30
tmin00Zbilinear90d20 1 QC2.44 [1.44, 3.04]2.47+0.50 [-1.11, 2.36]2.96 [1.67, 3.55]20% [0%, 41%]45%75%-0.09-0.082026-08-05 → 2026-08-30
tmin00Zbilinear365d20 1 QC2.44 [1.50, 3.09]2.47+0.50 [-1.22, 2.44]2.96 [1.68, 3.56]20% [0%, 43%]45%75%-0.09-0.082026-08-05 → 2026-08-30
tmin00Zbilinearall20 1 QC2.44 [1.34, 3.05]2.47+0.50 [-1.15, 2.14]2.96 [1.58, 3.54]20% [0%, 43%]45%75%-0.09-0.082026-08-05 → 2026-08-30
tmin00Znearest30d20 1 QC2.53 [1.60, 3.26]2.57+0.58 [-0.92, 2.31]3.14 [2.10, 3.80]25% [8%, 41%]45%65%-0.12-0.122026-08-05 → 2026-08-30
tmin00Znearest90d20 1 QC2.53 [1.25, 3.28]2.57+0.58 [-1.07, 2.51]3.14 [1.51, 3.85]25% [0%, 43%]45%65%-0.12-0.122026-08-05 → 2026-08-30
tmin00Znearest365d20 1 QC2.53 [1.28, 3.35]2.57+0.58 [-1.14, 2.58]3.14 [1.41, 3.87]25% [0%, 43%]45%65%-0.12-0.122026-08-05 → 2026-08-30
tmin00Znearestall20 1 QC2.53 [1.17, 3.29]2.57+0.58 [-1.12, 2.29]3.14 [1.37, 3.83]25% [0%, 43%]45%65%-0.12-0.122026-08-05 → 2026-08-30
tmin12Zbilinear30d21 1 QC1.90 [1.07, 2.58]1.89+0.80 [-0.78, 2.14]2.44 [1.39, 3.09]38% [21%, 64%]57%81%+0.17+0.192026-08-05 → 2026-08-30
tmin12Zbilinear90d21 1 QC1.90 [0.87, 2.66]1.89+0.80 [-0.90, 2.24]2.44 [1.14, 3.13]38% [20%, 78%]57%81%+0.17+0.192026-08-05 → 2026-08-30
tmin12Zbilinear365d21 1 QC1.90 [0.89, 2.67]1.89+0.80 [-0.94, 2.40]2.44 [1.15, 3.17]38% [19%, 75%]57%81%+0.17+0.192026-08-05 → 2026-08-30
tmin12Zbilinearall21 1 QC1.90 [0.85, 2.65]1.89+0.80 [-1.10, 2.14]2.44 [1.10, 3.11]38% [19%, 80%]57%81%+0.17+0.192026-08-05 → 2026-08-30
tmin12Znearest30d21 1 QC1.83 [1.05, 2.52]1.84+0.88 [-0.63, 2.17]2.38 [1.35, 3.05]43% [25%, 68%]57%81%+0.20+0.212026-08-05 → 2026-08-30
tmin12Znearest90d21 1 QC1.83 [0.83, 2.59]1.84+0.88 [-0.78, 2.26]2.38 [1.11, 3.08]43% [23%, 78%]57%81%+0.20+0.212026-08-05 → 2026-08-30
tmin12Znearest365d21 1 QC1.83 [0.87, 2.59]1.84+0.88 [-0.83, 2.40]2.38 [1.12, 3.11]43% [22%, 75%]57%81%+0.20+0.212026-08-05 → 2026-08-30
tmin12Znearestall21 1 QC1.83 [0.81, 2.55]1.84+0.88 [-0.90, 2.13]2.38 [1.11, 3.05]43% [22%, 80%]57%81%+0.20+0.212026-08-05 → 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 KATL, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: -1.71 °F2026-08-11: -6.53 °F2026-08-12: -11.35 °F2026-08-13: -2.69 °F2026-08-14: -1.41 °F2026-08-16: +3.02 °F2026-08-17: -1.07 °F2026-08-18: +3.72 °F2026-08-19: +1.04 °F2026-08-20: +2.71 °F2026-08-21: +6.48 °F2026-08-22: +1.52 °F2026-08-23: +0.04 °F2026-08-24: -0.57 °F2026-08-25: +0.67 °F2026-08-26: -8.92 °F2026-08-27: -12.43 °F2026-08-28: -7.58 °F2026-08-29: -3.2 °F2026-08-30: -3.28 °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
2026-08-30-3.28
2026-08-29-3.20
2026-08-28-7.58
2026-08-27-12.43
2026-08-26-8.92
2026-08-25+0.67
2026-08-24-0.57
2026-08-23+0.04
2026-08-22+1.52
2026-08-21+6.48
2026-08-20+2.71
2026-08-19+1.04
2026-08-18+3.72
2026-08-17-1.07
2026-08-16+3.02
2026-08-15—
2026-08-14-1.41
2026-08-13-2.69
2026-08-12-11.35
2026-08-11-6.53
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05-1.71

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KATL, 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: 1 day-12 to -10 °F: 1 day-10 to -8 °F: 1 day-8 to -6 °F: 2 days-6 to -4 °F: 0 days-4 to -2 °F: 3 days-2 to 0 °F: 4 days0 to 2 °F: 4 days2 to 4 °F: 3 days4 to 6 °F: 0 days6 to 8 °F: 1 day8 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| 2.86 · P90 |e| 9.17 °F-200+20 °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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.001
-12.00-10.001
-10.00-8.001
-8.00-6.002
-6.00-4.000
-4.00-2.003
-2.00+0.004
+0.00+2.004
+2.00+4.003
+4.00+6.000
+6.00+8.001
+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
2026-08204.00 -2.08

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 -0.10 [-2.09, 1.21] no
NCEP GFS 20 +0.55 [-1.15, 3.28] no
GraphCast (IFS init) 19 -1.01 [-3.02, -0.06] yes
Persistence (baseline) 20 +1.40 [-0.53, 3.17] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KATL (Atlanta Hartsfield), 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/KATL/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