Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

Atlanta Hartsfield · ECMWF IFS HRES · lead day 8

KATL · ifs_hres · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d17 1 QC2.62 [2.05, 3.15]2.71-0.28 [-2.27, 0.68]3.40 [2.55, 4.04]24% [9%, 33%]53%65%+0.32+0.292026-08-09 → 2026-08-30
tmax00Zbilinear90d17 1 QC2.62 [1.78, 3.20]2.71-0.28 [-2.70, 0.63]3.40 [1.83, 4.07]24% [0%, 33%]53%65%+0.32+0.292026-08-09 → 2026-08-30
tmax00Zbilinear365d17 1 QC2.62 [1.70, 3.19]2.71-0.28 [-2.56, 0.66]3.40 [1.80, 4.08]24% [0%, 33%]53%65%+0.32+0.292026-08-09 → 2026-08-30
tmax00Zbilinearall17 1 QC2.62 [1.80, 3.19]2.71-0.28 [-2.53, 0.69]3.40 [1.89, 4.07]24% [0%, 33%]53%65%+0.32+0.292026-08-09 → 2026-08-30
tmax00Znearest30d17 1 QC2.67 [1.97, 3.11]2.67-0.00 [-2.12, 1.05]3.26 [2.45, 3.75]18% [0%, 33%]53%65%+0.31+0.302026-08-09 → 2026-08-30
tmax00Znearest90d17 1 QC2.67 [1.68, 3.12]2.67-0.00 [-2.59, 1.05]3.26 [1.80, 3.76]18% [0%, 33%]53%65%+0.31+0.302026-08-09 → 2026-08-30
tmax00Znearest365d17 1 QC2.67 [1.68, 3.13]2.67-0.00 [-2.38, 1.11]3.26 [1.81, 3.77]18% [0%, 35%]53%65%+0.31+0.302026-08-09 → 2026-08-30
tmax00Znearestall17 1 QC2.67 [1.68, 3.14]2.67-0.00 [-2.33, 1.14]3.26 [2.03, 3.76]18% [0%, 35%]53%65%+0.31+0.302026-08-09 → 2026-08-30
tmax12Zbilinear30d17 1 QC4.20 [3.36, 5.91]3.91-1.71 [-5.18, -0.17]4.75 [3.86, 6.24]6% [0%, 14%]18%24%-0.08-0.022026-08-09 → 2026-08-30
tmax12Zbilinear90d17 1 QC4.20 [3.35, 6.68]3.91-1.71 [-6.68, -0.19]4.75 [3.79, 6.87]6% [0%, 13%]18%24%-0.08-0.022026-08-09 → 2026-08-30
tmax12Zbilinear365d17 1 QC4.20 [3.30, 7.24]3.91-1.71 [-7.24, -0.00]4.75 [3.72, 7.25]6% [0%, 14%]18%24%-0.08-0.022026-08-09 → 2026-08-30
tmax12Zbilinearall17 1 QC4.20 [3.29, 6.64]3.91-1.71 [-6.64, -0.11]4.75 [3.70, 6.80]6% [0%, 14%]18%24%-0.08-0.022026-08-09 → 2026-08-30
tmax12Znearest30d17 1 QC4.27 [3.56, 5.81]4.00-1.57 [-4.93, -0.07]4.77 [4.00, 6.07]6% [0%, 14%]18%35%-0.10-0.052026-08-09 → 2026-08-30
tmax12Znearest90d17 1 QC4.27 [3.51, 6.97]4.00-1.57 [-6.97, -0.05]4.77 [3.95, 7.03]6% [0%, 13%]18%35%-0.10-0.052026-08-09 → 2026-08-30
tmax12Znearest365d17 1 QC4.27 [3.48, 6.97]4.00-1.57 [-6.97, 0.09]4.77 [3.88, 7.02]6% [0%, 14%]18%35%-0.10-0.052026-08-09 → 2026-08-30
tmax12Znearestall17 1 QC4.27 [3.50, 6.84]4.00-1.57 [-6.84, -0.09]4.77 [3.91, 6.91]6% [0%, 14%]18%35%-0.10-0.052026-08-09 → 2026-08-30
tmin00Zbilinear30d17 1 QC2.53 [1.11, 3.28]2.70+1.48 [-0.57, 2.94]3.32 [1.70, 3.98]35% [21%, 70%]53%65%-0.08-0.172026-08-09 → 2026-08-30
tmin00Zbilinear90d17 1 QC2.53 [0.22, 3.34]2.70+1.48 [-1.03, 3.07]3.32 [0.23, 4.01]35% [21%, 100%]53%65%-0.08-0.172026-08-09 → 2026-08-30
tmin00Zbilinear365d17 1 QC2.53 [0.19, 3.38]2.70+1.48 [-1.10, 3.22]3.32 [0.21, 4.07]35% [20%, 100%]53%65%-0.08-0.172026-08-09 → 2026-08-30
tmin00Zbilinearall17 1 QC2.53 [0.19, 3.31]2.70+1.48 [-1.25, 3.05]3.32 [0.21, 4.00]35% [20%, 100%]53%65%-0.08-0.172026-08-09 → 2026-08-30
tmin00Znearest30d17 1 QC2.67 [1.15, 3.38]2.77+1.66 [-0.25, 3.11]3.53 [1.59, 4.16]35% [21%, 70%]47%65%-0.13-0.202026-08-09 → 2026-08-30
tmin00Znearest90d17 1 QC2.67 [0.45, 3.41]2.77+1.66 [-0.84, 3.17]3.53 [0.47, 4.15]35% [21%, 100%]47%65%-0.13-0.202026-08-09 → 2026-08-30
tmin00Znearest365d17 1 QC2.67 [0.36, 3.45]2.77+1.66 [-0.84, 3.31]3.53 [0.44, 4.20]35% [20%, 100%]47%65%-0.13-0.202026-08-09 → 2026-08-30
tmin00Znearestall17 1 QC2.67 [0.42, 3.36]2.77+1.66 [-0.90, 3.18]3.53 [0.47, 4.14]35% [20%, 100%]47%65%-0.13-0.202026-08-09 → 2026-08-30
tmin12Zbilinear30d17 1 QC2.53 [1.02, 3.70]2.44+1.71 [-0.20, 3.31]3.35 [1.35, 4.42]35% [20%, 62%]59%71%-0.08-0.052026-08-09 → 2026-08-30
tmin12Zbilinear90d17 1 QC2.53 [0.71, 3.78]2.44+1.71 [-0.53, 3.40]3.35 [1.02, 4.54]35% [19%, 67%]59%71%-0.08-0.052026-08-09 → 2026-08-30
tmin12Zbilinear365d17 1 QC2.53 [0.66, 4.01]2.44+1.71 [-0.53, 3.63]3.35 [0.96, 4.65]35% [16%, 71%]59%71%-0.08-0.052026-08-09 → 2026-08-30
tmin12Zbilinearall17 1 QC2.53 [0.80, 3.84]2.44+1.71 [-0.65, 3.50]3.35 [1.12, 4.55]35% [17%, 67%]59%71%-0.08-0.052026-08-09 → 2026-08-30
tmin12Znearest30d17 1 QC2.57 [1.07, 3.70]2.45+1.75 [-0.17, 3.31]3.39 [1.36, 4.43]35% [20%, 62%]47%71%-0.09-0.062026-08-09 → 2026-08-30
tmin12Znearest90d17 1 QC2.57 [0.74, 3.82]2.45+1.75 [-0.55, 3.39]3.39 [1.11, 4.53]35% [19%, 67%]47%71%-0.09-0.062026-08-09 → 2026-08-30
tmin12Znearest365d17 1 QC2.57 [0.61, 4.00]2.45+1.75 [-0.51, 3.59]3.39 [0.79, 4.66]35% [16%, 71%]47%71%-0.09-0.062026-08-09 → 2026-08-30
tmin12Znearestall17 1 QC2.57 [0.80, 3.80]2.45+1.75 [-0.61, 3.46]3.39 [1.12, 4.52]35% [17%, 67%]47%71%-0.09-0.062026-08-09 → 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 8, 00Z bilinear tmax+10+50-5-102026-08-09: -1.61 °F2026-08-15: -5.06 °F2026-08-16: +0.91 °F2026-08-17: +1.58 °F2026-08-18: +1.2 °F2026-08-19: +0.71 °F2026-08-20: +3.98 °F2026-08-21: +2.01 °F2026-08-22: -6.9 °F2026-08-23: +0.37 °F2026-08-24: +1.62 °F2026-08-25: +3.2 °F2026-08-26: +3.96 °F2026-08-27: +0.35 °F2026-08-28: -7.74 °F2026-08-29: -1.11 °F2026-08-30: -2.3 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.30
2026-08-29-1.11
2026-08-28-7.74
2026-08-27+0.35
2026-08-26+3.96
2026-08-25+3.20
2026-08-24+1.62
2026-08-23+0.37
2026-08-22-6.90
2026-08-21+2.01
2026-08-20+3.98
2026-08-19+0.71
2026-08-18+1.20
2026-08-17+1.58
2026-08-16+0.91
2026-08-15-5.06
2026-08-14—
2026-08-13—
2026-08-12—
2026-08-11—
2026-08-10—
2026-08-09-1.61

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KATL, lead day 8-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 1 day-7 to -6 °F: 1 day-6 to -5 °F: 1 day-5 to -4 °F: 0 days-4 to -3 °F: 0 days-3 to -2 °F: 1 day-2 to -1 °F: 2 days-1 to 0 °F: 0 days0 to 1 °F: 4 days1 to 2 °F: 3 days2 to 3 °F: 1 day3 to 4 °F: 3 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 1.62 · P90 |e| 5.8 °F-100+10 °Fn = 17 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
-9.00-8.000
-8.00-7.001
-7.00-6.001
-6.00-5.001
-5.00-4.000
-4.00-3.000
-3.00-2.001
-2.00-1.002
-1.00+0.000
+0.00+1.004
+1.00+2.003
+2.00+3.001
+3.00+4.003
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08172.62 -0.28

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-09 → 2026-08-30 17
ECMWF IFS HRES2026-08-09 → 2026-08-30 17
ECMWF IFS HRES2026-08-09 → 2026-08-30 17
ECMWF IFS HRES2026-08-09 → 2026-08-30 17

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 17 -2.11 [-5.91, -0.92] yes
NCEP GFS 17 -1.87 [-3.17, -0.40] yes
GraphCast (IFS init) 17 -2.43 [-5.38, -0.56] yes
Persistence (baseline) 17 -1.26 [-4.66, -0.20] yes

Cite this page

ShortCastCheck, KATL ifs_hres lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KATL/model/ifs_hres/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KATL (Atlanta Hartsfield), model ifs_hres, lead day 8. 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/8/

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