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

Atlanta Hartsfield · ECMWF AIFS Single · lead day 8

KATL · aifs_single · 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, 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
tmax00Zbilinear30d22 1 QC5.53 [3.78, 7.92]2.49-5.53 [-7.92, -3.78]6.33 [4.45, 8.48]5% [0%, 12%]14%23%-0.32+0.402026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC5.53 [3.73, 8.54]2.49-5.53 [-8.54, -3.73]6.33 [4.33, 8.94]5% [0%, 12%]14%23%-0.32+0.402026-08-09 → 2026-08-30
tmax00Zbilinear365d22 1 QC5.53 [3.43, 8.44]2.49-5.53 [-8.44, -3.43]6.33 [4.05, 8.93]5% [0%, 14%]14%23%-0.32+0.402026-08-09 → 2026-08-30
tmax00Zbilinearall22 1 QC5.53 [3.75, 8.39]2.49-5.53 [-8.39, -3.75]6.33 [4.38, 8.88]5% [0%, 13%]14%23%-0.32+0.402026-08-09 → 2026-08-30
tmax00Znearest30d22 1 QC5.63 [3.89, 8.04]2.52-5.63 [-8.04, -3.89]6.41 [4.55, 8.60]5% [0%, 12%]9%23%-0.35+0.402026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC5.63 [3.84, 8.68]2.52-5.63 [-8.68, -3.84]6.41 [4.43, 9.05]5% [0%, 12%]9%23%-0.35+0.402026-08-09 → 2026-08-30
tmax00Znearest365d22 1 QC5.63 [3.57, 8.58]2.52-5.63 [-8.58, -3.57]6.41 [4.11, 8.98]5% [0%, 14%]9%23%-0.35+0.402026-08-09 → 2026-08-30
tmax00Znearestall22 1 QC5.63 [3.87, 8.57]2.52-5.63 [-8.57, -3.87]6.41 [4.49, 8.98]5% [0%, 13%]9%23%-0.35+0.402026-08-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC5.22 [4.01, 6.73]2.24-4.97 [-6.73, -3.45]5.75 [4.47, 6.99]5% [0%, 12%]9%18%-0.25+0.462026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC5.22 [3.99, 7.13]2.24-4.97 [-7.13, -3.38]5.75 [4.42, 7.29]5% [0%, 13%]9%18%-0.25+0.462026-08-09 → 2026-08-30
tmax12Zbilinear365d22 1 QC5.22 [3.83, 7.24]2.24-4.97 [-7.24, -3.12]5.75 [4.25, 7.39]5% [0%, 14%]9%18%-0.25+0.462026-08-09 → 2026-08-30
tmax12Zbilinearall22 1 QC5.22 [3.89, 7.09]2.24-4.97 [-7.09, -3.27]5.75 [4.38, 7.26]5% [0%, 14%]9%18%-0.25+0.462026-08-09 → 2026-08-30
tmax12Znearest30d22 1 QC5.33 [4.12, 6.84]2.28-5.09 [-6.83, -3.56]5.87 [4.56, 7.09]5% [0%, 12%]9%18%-0.27+0.452026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC5.33 [4.09, 7.27]2.28-5.09 [-7.27, -3.49]5.87 [4.52, 7.44]5% [0%, 13%]9%18%-0.27+0.452026-08-09 → 2026-08-30
tmax12Znearest365d22 1 QC5.33 [3.95, 7.34]2.28-5.09 [-7.34, -3.27]5.87 [4.37, 7.49]5% [0%, 14%]9%18%-0.27+0.452026-08-09 → 2026-08-30
tmax12Znearestall22 1 QC5.33 [3.98, 7.24]2.28-5.09 [-7.24, -3.38]5.87 [4.49, 7.41]5% [0%, 14%]9%18%-0.27+0.452026-08-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC1.99 [1.37, 2.39]1.99-0.04 [-1.22, 1.06]2.72 [1.70, 3.53]27% [10%, 50%]68%82%+0.22+0.232026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC1.99 [1.16, 2.33]1.99-0.04 [-1.32, 1.17]2.72 [1.37, 3.58]27% [10%, 57%]68%82%+0.22+0.232026-08-09 → 2026-08-30
tmin00Zbilinear365d22 1 QC1.99 [1.04, 2.33]1.99-0.04 [-1.41, 1.25]2.72 [1.21, 3.62]27% [7%, 57%]68%82%+0.22+0.232026-08-09 → 2026-08-30
tmin00Zbilinearall22 1 QC1.99 [1.04, 2.35]1.99-0.04 [-1.41, 1.16]2.72 [1.29, 3.64]27% [7%, 60%]68%82%+0.22+0.232026-08-09 → 2026-08-30
tmin00Znearest30d22 1 QC2.00 [1.39, 2.40]2.00-0.13 [-1.32, 0.99]2.71 [1.68, 3.55]23% [3%, 45%]64%82%+0.22+0.222026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC2.00 [1.18, 2.34]2.00-0.13 [-1.45, 1.08]2.71 [1.34, 3.59]23% [0%, 55%]64%82%+0.22+0.222026-08-09 → 2026-08-30
tmin00Znearest365d22 1 QC2.00 [1.10, 2.32]2.00-0.13 [-1.54, 1.17]2.71 [1.23, 3.64]23% [0%, 54%]64%82%+0.22+0.222026-08-09 → 2026-08-30
tmin00Znearestall22 1 QC2.00 [1.10, 2.34]2.00-0.13 [-1.53, 1.07]2.71 [1.30, 3.65]23% [0%, 57%]64%82%+0.22+0.222026-08-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC2.44 [1.89, 2.81]2.37-0.45 [-1.96, 0.86]3.19 [2.33, 3.83]18% [4%, 36%]59%73%+0.04+0.082026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC2.44 [1.74, 2.77]2.37-0.45 [-2.11, 0.87]3.19 [2.15, 3.87]18% [4%, 40%]59%73%+0.04+0.082026-08-09 → 2026-08-30
tmin12Zbilinear365d22 1 QC2.44 [1.72, 2.78]2.37-0.45 [-2.20, 0.98]3.19 [2.14, 3.91]18% [0%, 39%]59%73%+0.04+0.082026-08-09 → 2026-08-30
tmin12Zbilinearall22 1 QC2.44 [1.71, 2.79]2.37-0.45 [-2.17, 0.92]3.19 [2.11, 3.96]18% [0%, 41%]59%73%+0.04+0.082026-08-09 → 2026-08-30
tmin12Znearest30d22 1 QC2.48 [1.93, 2.86]2.39-0.54 [-2.03, 0.79]3.23 [2.35, 3.90]18% [0%, 44%]59%73%+0.03+0.072026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC2.48 [1.75, 2.82]2.39-0.54 [-2.26, 0.80]3.23 [2.20, 3.96]18% [0%, 50%]59%73%+0.03+0.072026-08-09 → 2026-08-30
tmin12Znearest365d22 1 QC2.48 [1.70, 2.84]2.39-0.54 [-2.30, 0.93]3.23 [2.21, 3.98]18% [0%, 50%]59%73%+0.03+0.072026-08-09 → 2026-08-30
tmin12Znearestall22 1 QC2.48 [1.70, 2.86]2.39-0.54 [-2.29, 0.86]3.23 [2.12, 4.03]18% [0%, 50%]59%73%+0.03+0.072026-08-09 → 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 AIFS Single at KATL, lead day 8, 00Z bilinear tmax+20+100-10-202026-08-09: -8.34 °F2026-08-10: -13.71 °F2026-08-11: -7.22 °F2026-08-12: -7.25 °F2026-08-13: -8.44 °F2026-08-14: -4.57 °F2026-08-15: -4.19 °F2026-08-16: -3.17 °F2026-08-17: -5.07 °F2026-08-18: -0.41 °F2026-08-19: -1.99 °F2026-08-20: -4.44 °F2026-08-21: -1.23 °F2026-08-22: -2.86 °F2026-08-23: -7.24 °F2026-08-24: -5.36 °F2026-08-25: -7.96 °F2026-08-26: -2.39 °F2026-08-27: -4.51 °F2026-08-28: -6.98 °F2026-08-29: -4.33 °F2026-08-30: -10.07 °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
2026-08-30-10.07
2026-08-29-4.33
2026-08-28-6.98
2026-08-27-4.51
2026-08-26-2.39
2026-08-25-7.96
2026-08-24-5.36
2026-08-23-7.24
2026-08-22-2.86
2026-08-21-1.23
2026-08-20-4.44
2026-08-19-1.99
2026-08-18-0.41
2026-08-17-5.07
2026-08-16-3.17
2026-08-15-4.19
2026-08-14-4.57
2026-08-13-8.44
2026-08-12-7.25
2026-08-11-7.22
2026-08-10-13.71
2026-08-09-8.34

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KATL, lead day 8-20 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: 2 days-8 to -6 °F: 5 days-6 to -4 °F: 7 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| 4.82 · P90 |e| 8.43 °F-200+20 °Fn = 22 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
-10.00-8.002
-8.00-6.005
-6.00-4.007
-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
2026-08225.53 -5.53

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22

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 22 +1.82 [-0.70, 6.50] no
GraphCast (IFS init) 22 -0.12 [-1.38, 1.40] no
ECMWF IFS HRES 17 +2.11 [0.92, 5.91] yes
Persistence (baseline) 22 +1.35 [-0.13, 3.41] no

Cite this page

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

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