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

Atlanta Hartsfield · ECMWF AIFS Single · lead day 9

KATL · aifs_single · 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, 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
tmax00Zbilinear30d21 1 QC5.79 [4.55, 7.13]2.31-5.79 [-7.13, -4.55]6.47 [5.12, 7.82]0% [0%, 0%]14%19%-0.34+0.462026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC5.79 [4.47, 7.46]2.31-5.79 [-7.46, -4.47]6.47 [4.99, 8.05]0% [0%, 0%]14%19%-0.34+0.462026-08-10 → 2026-08-30
tmax00Zbilinear365d21 1 QC5.79 [4.41, 7.58]2.31-5.79 [-7.58, -4.41]6.47 [4.97, 8.12]0% [0%, 0%]14%19%-0.34+0.462026-08-10 → 2026-08-30
tmax00Zbilinearall21 1 QC5.79 [4.59, 7.46]2.31-5.79 [-7.46, -4.59]6.47 [5.15, 7.98]0% [0%, 0%]14%19%-0.34+0.462026-08-10 → 2026-08-30
tmax00Znearest30d21 1 QC5.97 [4.74, 7.31]2.33-5.97 [-7.31, -4.74]6.65 [5.29, 8.03]0% [0%, 0%]0%19%-0.38+0.462026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC5.97 [4.63, 7.65]2.33-5.97 [-7.65, -4.63]6.65 [5.18, 8.31]0% [0%, 0%]0%19%-0.38+0.462026-08-10 → 2026-08-30
tmax00Znearest365d21 1 QC5.97 [4.59, 7.73]2.33-5.97 [-7.73, -4.59]6.65 [5.12, 8.32]0% [0%, 0%]0%19%-0.38+0.462026-08-10 → 2026-08-30
tmax00Znearestall21 1 QC5.97 [4.75, 7.64]2.33-5.97 [-7.64, -4.75]6.65 [5.24, 8.17]0% [0%, 0%]0%19%-0.38+0.462026-08-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC5.63 [4.03, 7.24]2.60-5.63 [-7.24, -4.03]6.46 [4.95, 7.89]10% [0%, 23%]14%19%-0.30+0.402026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC5.63 [3.92, 7.56]2.60-5.63 [-7.56, -3.92]6.46 [4.71, 8.16]10% [0%, 25%]14%19%-0.30+0.402026-08-10 → 2026-08-30
tmax12Zbilinear365d21 1 QC5.63 [3.79, 7.61]2.60-5.63 [-7.61, -3.78]6.46 [4.55, 8.19]10% [0%, 26%]14%19%-0.30+0.402026-08-10 → 2026-08-30
tmax12Zbilinearall21 1 QC5.63 [4.07, 7.37]2.60-5.63 [-7.37, -4.06]6.46 [4.89, 7.96]10% [0%, 23%]14%19%-0.30+0.402026-08-10 → 2026-08-30
tmax12Znearest30d21 1 QC5.80 [4.20, 7.43]2.57-5.80 [-7.43, -4.20]6.61 [5.07, 8.07]10% [0%, 23%]14%14%-0.34+0.402026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC5.80 [4.10, 7.78]2.57-5.80 [-7.78, -4.10]6.61 [4.80, 8.37]10% [0%, 25%]14%14%-0.34+0.402026-08-10 → 2026-08-30
tmax12Znearest365d21 1 QC5.80 [3.95, 7.83]2.57-5.80 [-7.83, -3.95]6.61 [4.69, 8.42]10% [0%, 26%]14%14%-0.34+0.402026-08-10 → 2026-08-30
tmax12Znearestall21 1 QC5.80 [4.22, 7.58]2.57-5.80 [-7.58, -4.22]6.61 [5.01, 8.20]10% [0%, 23%]14%14%-0.34+0.402026-08-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC2.16 [1.61, 2.54]2.15-0.08 [-1.11, 0.99]2.56 [1.95, 2.90]19% [0%, 38%]52%71%+0.22+0.222026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC2.16 [1.28, 2.51]2.15-0.08 [-1.15, 1.16]2.56 [1.62, 2.88]19% [0%, 43%]52%71%+0.22+0.222026-08-10 → 2026-08-30
tmin00Zbilinear365d21 1 QC2.16 [1.39, 2.55]2.15-0.08 [-1.16, 1.20]2.56 [1.68, 2.89]19% [0%, 43%]52%71%+0.22+0.222026-08-10 → 2026-08-30
tmin00Zbilinearall21 1 QC2.16 [1.14, 2.57]2.15-0.08 [-1.16, 1.04]2.56 [1.15, 2.87]19% [0%, 43%]52%71%+0.22+0.222026-08-10 → 2026-08-30
tmin00Znearest30d21 1 QC2.17 [1.60, 2.56]2.17-0.16 [-1.19, 0.91]2.59 [1.94, 2.95]19% [0%, 38%]52%71%+0.21+0.222026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC2.17 [1.32, 2.52]2.17-0.16 [-1.24, 1.08]2.59 [1.61, 2.96]19% [0%, 43%]52%71%+0.21+0.222026-08-10 → 2026-08-30
tmin00Znearest365d21 1 QC2.17 [1.41, 2.57]2.17-0.16 [-1.24, 1.12]2.59 [1.69, 2.97]19% [0%, 43%]52%71%+0.21+0.222026-08-10 → 2026-08-30
tmin00Znearestall21 1 QC2.17 [1.24, 2.58]2.17-0.16 [-1.24, 0.95]2.59 [1.25, 2.94]19% [0%, 43%]52%71%+0.21+0.222026-08-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC2.30 [1.83, 2.67]2.30-0.13 [-1.53, 1.22]2.91 [2.25, 3.53]24% [14%, 40%]48%86%+0.17+0.172026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC2.30 [1.77, 2.60]2.30-0.13 [-1.70, 1.38]2.91 [2.09, 3.49]24% [14%, 43%]48%86%+0.17+0.172026-08-10 → 2026-08-30
tmin12Zbilinear365d21 1 QC2.30 [1.80, 2.60]2.30-0.13 [-1.76, 1.48]2.91 [2.10, 3.46]24% [14%, 43%]48%86%+0.17+0.172026-08-10 → 2026-08-30
tmin12Zbilinearall21 1 QC2.30 [1.67, 2.58]2.30-0.13 [-1.68, 1.38]2.91 [2.02, 3.44]24% [14%, 47%]48%86%+0.17+0.172026-08-10 → 2026-08-30
tmin12Znearest30d21 1 QC2.31 [1.85, 2.68]2.30-0.22 [-1.62, 1.15]2.92 [2.28, 3.54]24% [14%, 40%]52%81%+0.17+0.172026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC2.31 [1.76, 2.63]2.30-0.22 [-1.80, 1.32]2.92 [2.14, 3.51]24% [14%, 43%]52%81%+0.17+0.172026-08-10 → 2026-08-30
tmin12Znearest365d21 1 QC2.31 [1.75, 2.63]2.30-0.22 [-1.84, 1.42]2.92 [2.19, 3.48]24% [14%, 43%]52%81%+0.17+0.172026-08-10 → 2026-08-30
tmin12Znearestall21 1 QC2.31 [1.75, 2.62]2.30-0.22 [-1.76, 1.34]2.92 [2.11, 3.47]24% [14%, 47%]52%81%+0.17+0.172026-08-10 → 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 AIFS Single at KATL, lead day 9, 00Z bilinear tmax+20+100-10-202026-08-10: -6.98 °F2026-08-11: -8.59 °F2026-08-12: -4.55 °F2026-08-13: -13.96 °F2026-08-14: -8.12 °F2026-08-15: -4.91 °F2026-08-16: -3.24 °F2026-08-17: -4.26 °F2026-08-18: -1.81 °F2026-08-19: -8.18 °F2026-08-20: -2.42 °F2026-08-21: -1.9 °F2026-08-22: -6.74 °F2026-08-23: -5.59 °F2026-08-24: -7.86 °F2026-08-25: -6.84 °F2026-08-26: -7.83 °F2026-08-27: -1.86 °F2026-08-28: -6.2 °F2026-08-29: -3.1 °F2026-08-30: -6.72 °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
2026-08-30-6.72
2026-08-29-3.10
2026-08-28-6.20
2026-08-27-1.86
2026-08-26-7.83
2026-08-25-6.84
2026-08-24-7.86
2026-08-23-5.59
2026-08-22-6.74
2026-08-21-1.90
2026-08-20-2.42
2026-08-19-8.18
2026-08-18-1.81
2026-08-17-4.26
2026-08-16-3.24
2026-08-15-4.91
2026-08-14-8.12
2026-08-13-13.96
2026-08-12-4.55
2026-08-11-8.59
2026-08-10-6.98

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KATL, 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: 1 day-12 to -10 °F: 0 days-10 to -8 °F: 3 days-8 to -6 °F: 7 days-6 to -4 °F: 4 days-4 to -2 °F: 3 days-2 to 0 °F: 3 days0 to 2 °F: 0 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| 6.2 · P90 |e| 8.18 °F-200+20 °Fn = 21 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
-12.00-10.000
-10.00-8.003
-8.00-6.007
-6.00-4.004
-4.00-2.003
-2.00+0.003
+0.00+2.000
+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
2026-08215.79 -5.79

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21
ECMWF AIFS Single2026-08-10 → 2026-08-30 21

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 21 +0.83 [-1.15, 3.01] no
GraphCast (IFS init) 21 -0.23 [-2.44, 1.18] no
ECMWF IFS HRES 16 +1.56 [0.41, 3.11] yes
Persistence (baseline) 21 +1.46 [0.07, 2.92] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KATL (Atlanta Hartsfield), model aifs_single, 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/KATL/model/aifs_single/lead/9/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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