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

Washington Reagan · ECMWF AIFS Single · lead day 4

KDCA · 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 QC2.83 [1.98, 3.61]1.82-2.52 [-3.38, -1.64]3.29 [2.46, 3.93]23% [8%, 39%]35%50%+0.38+0.602026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC2.83 [1.87, 3.71]1.82-2.52 [-3.49, -1.55]3.29 [2.32, 4.01]23% [6%, 41%]35%50%+0.38+0.602026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC2.83 [1.81, 3.70]1.82-2.52 [-3.50, -1.48]3.29 [2.24, 4.02]23% [5%, 42%]35%50%+0.38+0.602026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC2.83 [1.79, 3.73]1.82-2.52 [-3.50, -1.47]3.29 [2.25, 4.04]23% [0%, 43%]35%50%+0.38+0.602026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC2.66 [1.83, 3.43]1.81-2.28 [-3.19, -1.37]3.11 [2.29, 3.76]19% [7%, 33%]42%54%+0.41+0.602026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC2.66 [1.70, 3.55]1.81-2.28 [-3.30, -1.30]3.11 [2.15, 3.84]19% [5%, 33%]42%54%+0.41+0.602026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC2.66 [1.67, 3.53]1.81-2.28 [-3.36, -1.22]3.11 [2.10, 3.87]19% [5%, 35%]42%54%+0.41+0.602026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC2.66 [1.66, 3.59]1.81-2.28 [-3.34, -1.24]3.11 [2.09, 3.84]19% [0%, 33%]42%54%+0.41+0.602026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC2.75 [1.97, 3.53]1.76-2.30 [-3.42, -1.10]3.23 [2.53, 3.81]27% [8%, 46%]27%50%+0.39+0.612026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC2.75 [1.83, 3.65]1.76-2.30 [-3.60, -1.01]3.23 [2.38, 3.89]27% [3%, 50%]27%50%+0.39+0.612026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC2.75 [1.81, 3.70]1.76-2.30 [-3.63, -0.90]3.23 [2.33, 3.91]27% [0%, 50%]27%50%+0.39+0.612026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC2.75 [1.81, 3.66]1.76-2.30 [-3.63, -0.92]3.23 [2.36, 3.90]27% [0%, 50%]27%50%+0.39+0.612026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC2.61 [1.90, 3.35]1.76-2.07 [-3.24, -0.84]3.07 [2.42, 3.63]23% [7%, 38%]38%50%+0.42+0.612026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC2.61 [1.76, 3.49]1.76-2.07 [-3.44, -0.72]3.07 [2.29, 3.73]23% [3%, 40%]38%50%+0.42+0.612026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC2.61 [1.75, 3.52]1.76-2.07 [-3.50, -0.64]3.07 [2.24, 3.73]23% [0%, 40%]38%50%+0.42+0.612026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC2.61 [1.75, 3.50]1.76-2.07 [-3.46, -0.67]3.07 [2.27, 3.71]23% [0%, 40%]38%50%+0.42+0.612026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC2.53 [2.03, 3.03]2.55+0.43 [-0.84, 1.58]2.94 [2.31, 3.45]19% [4%, 33%]38%65%+0.28+0.272026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC2.53 [1.92, 3.06]2.55+0.43 [-1.09, 1.69]2.94 [2.21, 3.46]19% [0%, 33%]38%65%+0.28+0.272026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC2.53 [1.91, 3.11]2.55+0.43 [-1.19, 1.80]2.94 [2.18, 3.50]19% [0%, 33%]38%65%+0.28+0.272026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC2.53 [1.93, 3.06]2.55+0.43 [-1.30, 1.80]2.94 [2.15, 3.48]19% [0%, 33%]38%65%+0.28+0.272026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC2.51 [2.03, 3.00]2.51+0.70 [-0.57, 1.85]2.96 [2.34, 3.47]19% [8%, 30%]38%65%+0.28+0.282026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC2.51 [1.95, 3.02]2.51+0.70 [-0.82, 1.96]2.96 [2.22, 3.51]19% [5%, 29%]38%65%+0.28+0.282026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC2.51 [1.92, 3.06]2.51+0.70 [-0.94, 2.05]2.96 [2.21, 3.54]19% [6%, 29%]38%65%+0.28+0.282026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC2.51 [1.96, 3.00]2.51+0.70 [-1.06, 2.07]2.96 [2.17, 3.52]19% [0%, 29%]38%65%+0.28+0.282026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC2.27 [1.99, 2.57]2.29+0.24 [-1.05, 1.38]2.69 [2.24, 3.09]19% [6%, 32%]50%73%+0.35+0.342026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC2.27 [1.95, 2.57]2.29+0.24 [-1.31, 1.49]2.69 [2.20, 3.10]19% [5%, 33%]50%73%+0.35+0.342026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC2.27 [1.86, 2.61]2.29+0.24 [-1.50, 1.55]2.69 [2.13, 3.11]19% [0%, 35%]50%73%+0.35+0.342026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC2.27 [1.87, 2.59]2.29+0.24 [-1.46, 1.54]2.69 [2.11, 3.11]19% [0%, 33%]50%73%+0.35+0.342026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC2.25 [1.90, 2.59]2.28+0.51 [-0.77, 1.66]2.72 [2.19, 3.15]23% [13%, 33%]46%77%+0.36+0.352026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC2.25 [1.86, 2.58]2.28+0.51 [-1.04, 1.78]2.72 [2.10, 3.18]23% [11%, 33%]46%77%+0.36+0.352026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC2.25 [1.80, 2.63]2.28+0.51 [-1.24, 1.84]2.72 [2.05, 3.20]23% [11%, 36%]46%77%+0.36+0.352026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC2.25 [1.81, 2.61]2.28+0.51 [-1.20, 1.84]2.72 [2.06, 3.20]23% [11%, 36%]46%77%+0.36+0.352026-08-05 → 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 KDCA, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -4.04 °F2026-08-06: +0.17 °F2026-08-07: -2.18 °F2026-08-08: -1.92 °F2026-08-09: -1.57 °F2026-08-10: +0.86 °F2026-08-11: -1.02 °F2026-08-12: -3.01 °F2026-08-13: -0.62 °F2026-08-14: +0.89 °F2026-08-15: -4.88 °F2026-08-16: -0.71 °F2026-08-17: -3.68 °F2026-08-18: -4.36 °F2026-08-19: -3.94 °F2026-08-20: -4.58 °F2026-08-21: -3.41 °F2026-08-22: +2.15 °F2026-08-23: -2.61 °F2026-08-24: -4.82 °F2026-08-25: -4.69 °F2026-08-26: -2 °F2026-08-27: -5.79 °F2026-08-28: -5.19 °F2026-08-29: -0.57 °F2026-08-30: -3.92 °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
2026-08-30-3.92
2026-08-29-0.57
2026-08-28-5.19
2026-08-27-5.79
2026-08-26-2.00
2026-08-25-4.69
2026-08-24-4.82
2026-08-23-2.61
2026-08-22+2.15
2026-08-21-3.41
2026-08-20-4.58
2026-08-19-3.94
2026-08-18-4.36
2026-08-17-3.68
2026-08-16-0.71
2026-08-15-4.88
2026-08-14+0.89
2026-08-13-0.62
2026-08-12-3.01
2026-08-11-1.02
2026-08-10+0.86
2026-08-09-1.57
2026-08-08-1.92
2026-08-07-2.18
2026-08-06+0.17
2026-08-05-4.04

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KDCA, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 2 days-5 to -4 °F: 6 days-4 to -3 °F: 5 days-3 to -2 °F: 3 days-2 to -1 °F: 3 days-1 to 0 °F: 3 days0 to 1 °F: 3 days1 to 2 °F: 0 days2 to 3 °F: 1 day3 to 4 °F: 0 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| 2.81 · P90 |e| 4.85 °F-100+10 °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
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.002
-5.00-4.006
-4.00-3.005
-3.00-2.003
-2.00-1.003
-1.00+0.003
+0.00+1.003
+1.00+2.000
+2.00+3.001
+3.00+4.000
+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
2026-08262.83 -2.52

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 -0.86 [-2.53, 1.22] no
GraphCast (IFS init) 25 -2.03 [-2.52, -1.58] yes
ECMWF IFS HRES 20 -0.37 [-2.10, 0.77] no
Persistence (baseline) 26 -1.71 [-2.78, -0.16] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDCA (Washington Reagan), 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/KDCA/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