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

Seattle-Tacoma · ECMWF AIFS Single · lead day 1

KSEA · aifs_single · lead 1

Target day = initialization date + 1 day. 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
tmax00Zbilinear30d29 1 QC5.32 [4.19, 6.46]1.51-5.32 [-6.46, -4.19]5.70 [4.64, 6.75]7% [0%, 15%]7%14%-0.71+0.512026-08-02 → 2026-08-30
tmax00Zbilinear90d29 1 QC5.32 [4.01, 6.51]1.51-5.32 [-6.51, -4.01]5.70 [4.48, 6.76]7% [0%, 16%]7%14%-0.71+0.512026-08-02 → 2026-08-30
tmax00Zbilinear365d29 1 QC5.32 [4.08, 6.55]1.51-5.32 [-6.55, -4.08]5.70 [4.51, 6.77]7% [0%, 17%]7%14%-0.71+0.512026-08-02 → 2026-08-30
tmax00Zbilinearall29 1 QC5.32 [3.87, 6.49]1.51-5.32 [-6.49, -3.87]5.70 [4.34, 6.74]7% [0%, 18%]7%14%-0.71+0.512026-08-02 → 2026-08-30
tmax00Znearest30d29 1 QC4.97 [3.84, 6.14]1.56-4.97 [-6.14, -3.83]5.39 [4.32, 6.47]7% [0%, 15%]10%14%-0.60+0.502026-08-02 → 2026-08-30
tmax00Znearest90d29 1 QC4.97 [3.64, 6.18]1.56-4.97 [-6.18, -3.63]5.39 [4.14, 6.46]7% [0%, 16%]10%14%-0.60+0.502026-08-02 → 2026-08-30
tmax00Znearest365d29 1 QC4.97 [3.74, 6.22]1.56-4.97 [-6.22, -3.73]5.39 [4.20, 6.48]7% [0%, 17%]10%14%-0.60+0.502026-08-02 → 2026-08-30
tmax00Znearestall29 1 QC4.97 [3.51, 6.18]1.56-4.97 [-6.18, -3.50]5.39 [4.01, 6.48]7% [0%, 18%]10%14%-0.60+0.502026-08-02 → 2026-08-30
tmax12Zbilinear30d29 1 QC5.20 [4.13, 6.26]1.49-5.20 [-6.26, -4.13]5.56 [4.61, 6.46]3% [0%, 11%]7%14%-0.68+0.522026-08-02 → 2026-08-30
tmax12Zbilinear90d29 1 QC5.20 [3.97, 6.26]1.49-5.20 [-6.26, -3.97]5.56 [4.46, 6.48]3% [0%, 12%]7%14%-0.68+0.522026-08-02 → 2026-08-30
tmax12Zbilinear365d29 1 QC5.20 [3.97, 6.36]1.49-5.20 [-6.36, -3.97]5.56 [4.49, 6.54]3% [0%, 12%]7%14%-0.68+0.522026-08-02 → 2026-08-30
tmax12Zbilinearall29 1 QC5.20 [3.84, 6.31]1.49-5.20 [-6.31, -3.84]5.56 [4.37, 6.49]3% [0%, 14%]7%14%-0.68+0.522026-08-02 → 2026-08-30
tmax12Znearest30d29 1 QC4.90 [3.87, 5.95]1.53-4.87 [-5.95, -3.79]5.26 [4.31, 6.20]3% [0%, 11%]10%14%-0.58+0.512026-08-02 → 2026-08-30
tmax12Znearest90d29 1 QC4.90 [3.72, 5.98]1.53-4.87 [-5.98, -3.62]5.26 [4.15, 6.21]3% [0%, 12%]10%14%-0.58+0.512026-08-02 → 2026-08-30
tmax12Znearest365d29 1 QC4.90 [3.73, 6.06]1.53-4.87 [-6.06, -3.62]5.26 [4.18, 6.26]3% [0%, 12%]10%14%-0.58+0.512026-08-02 → 2026-08-30
tmax12Znearestall29 1 QC4.90 [3.59, 6.02]1.53-4.87 [-6.02, -3.45]5.26 [4.06, 6.23]3% [0%, 14%]10%14%-0.58+0.512026-08-02 → 2026-08-30
tmin00Zbilinear30d29 1 QC1.68 [1.21, 2.23]1.22-1.22 [-2.14, -0.28]2.05 [1.57, 2.49]38% [14%, 59%]69%86%-0.04+0.262026-08-02 → 2026-08-30
tmin00Zbilinear90d29 1 QC1.68 [1.18, 2.32]1.22-1.22 [-2.29, -0.25]2.05 [1.51, 2.55]38% [11%, 60%]69%86%-0.04+0.262026-08-02 → 2026-08-30
tmin00Zbilinear365d29 1 QC1.68 [1.16, 2.27]1.22-1.22 [-2.25, -0.13]2.05 [1.48, 2.52]38% [8%, 62%]69%86%-0.04+0.262026-08-02 → 2026-08-30
tmin00Zbilinearall29 1 QC1.68 [1.17, 2.32]1.22-1.22 [-2.31, -0.22]2.05 [1.49, 2.53]38% [7%, 60%]69%86%-0.04+0.262026-08-02 → 2026-08-30
tmin00Znearest30d29 1 QC1.63 [1.14, 2.23]1.31-1.14 [-2.12, -0.13]2.07 [1.51, 2.57]38% [14%, 59%]72%76%-0.01+0.202026-08-02 → 2026-08-30
tmin00Znearest90d29 1 QC1.63 [1.08, 2.33]1.31-1.14 [-2.26, -0.14]2.07 [1.43, 2.63]38% [10%, 60%]72%76%-0.01+0.202026-08-02 → 2026-08-30
tmin00Znearest365d29 1 QC1.63 [1.07, 2.27]1.31-1.14 [-2.25, -0.01]2.07 [1.42, 2.60]38% [8%, 62%]72%76%-0.01+0.202026-08-02 → 2026-08-30
tmin00Znearestall29 1 QC1.63 [1.07, 2.29]1.31-1.14 [-2.28, -0.11]2.07 [1.44, 2.60]38% [7%, 60%]72%76%-0.01+0.202026-08-02 → 2026-08-30
tmin12Zbilinear30d29 1 QC1.65 [1.13, 2.22]1.14-1.37 [-2.18, -0.55]2.03 [1.49, 2.53]34% [14%, 57%]69%79%-0.02+0.312026-08-02 → 2026-08-30
tmin12Zbilinear90d29 1 QC1.65 [1.12, 2.32]1.14-1.37 [-2.29, -0.54]2.03 [1.45, 2.59]34% [9%, 56%]69%79%-0.02+0.312026-08-02 → 2026-08-30
tmin12Zbilinear365d29 1 QC1.65 [1.06, 2.28]1.14-1.37 [-2.27, -0.45]2.03 [1.43, 2.56]34% [8%, 59%]69%79%-0.02+0.312026-08-02 → 2026-08-30
tmin12Zbilinearall29 1 QC1.65 [1.11, 2.33]1.14-1.37 [-2.33, -0.50]2.03 [1.45, 2.57]34% [6%, 57%]69%79%-0.02+0.312026-08-02 → 2026-08-30
tmin12Znearest30d29 1 QC1.64 [1.09, 2.28]1.22-1.33 [-2.21, -0.45]2.09 [1.47, 2.64]34% [14%, 57%]66%76%-0.01+0.252026-08-02 → 2026-08-30
tmin12Znearest90d29 1 QC1.64 [1.05, 2.36]1.22-1.33 [-2.32, -0.46]2.09 [1.39, 2.71]34% [9%, 56%]66%76%-0.01+0.252026-08-02 → 2026-08-30
tmin12Znearest365d29 1 QC1.64 [1.03, 2.32]1.22-1.33 [-2.30, -0.35]2.09 [1.37, 2.66]34% [8%, 59%]66%76%-0.01+0.252026-08-02 → 2026-08-30
tmin12Znearestall29 1 QC1.64 [1.06, 2.34]1.22-1.33 [-2.34, -0.45]2.09 [1.38, 2.67]34% [6%, 57%]66%76%-0.01+0.252026-08-02 → 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 KSEA, lead day 1, 00Z bilinear tmax+10+50-5-102026-08-02: -3.69 °F2026-08-03: -2.6 °F2026-08-04: -0.46 °F2026-08-05: -4.02 °F2026-08-06: -5.38 °F2026-08-07: -7.32 °F2026-08-08: -6.55 °F2026-08-09: -4.58 °F2026-08-10: -0.96 °F2026-08-11: -4.43 °F2026-08-12: -6.29 °F2026-08-13: -4.88 °F2026-08-14: -4.84 °F2026-08-15: -5.4 °F2026-08-16: -6.67 °F2026-08-17: -8.73 °F2026-08-18: -7.15 °F2026-08-19: -9.79 °F2026-08-20: -7.79 °F2026-08-21: -5.58 °F2026-08-22: -7.32 °F2026-08-23: -5.2 °F2026-08-24: -5.38 °F2026-08-25: -5.08 °F2026-08-26: -4.24 °F2026-08-27: -5.91 °F2026-08-28: -5.24 °F2026-08-29: -6.44 °F2026-08-30: -2.21 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.21
2026-08-29-6.44
2026-08-28-5.24
2026-08-27-5.91
2026-08-26-4.24
2026-08-25-5.08
2026-08-24-5.38
2026-08-23-5.20
2026-08-22-7.32
2026-08-21-5.58
2026-08-20-7.79
2026-08-19-9.79
2026-08-18-7.15
2026-08-17-8.73
2026-08-16-6.67
2026-08-15-5.40
2026-08-14-4.84
2026-08-13-4.88
2026-08-12-6.29
2026-08-11-4.43
2026-08-10-0.96
2026-08-09-4.58
2026-08-08-6.55
2026-08-07-7.32
2026-08-06-5.38
2026-08-05-4.02
2026-08-04-0.46
2026-08-03-2.60
2026-08-02-3.69

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KSEA, lead day 1-10 to -9 °F: 1 day-9 to -8 °F: 1 day-8 to -7 °F: 4 days-7 to -6 °F: 4 days-6 to -5 °F: 8 days-5 to -4 °F: 6 days-4 to -3 °F: 1 day-3 to -2 °F: 2 days-2 to -1 °F: 0 days-1 to 0 °F: 2 days0 to 1 °F: 0 days1 to 2 °F: 0 days2 to 3 °F: 0 days3 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| 5.38 · P90 |e| 7.42 °F-100+10 °Fn = 29 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
-10.00-9.001
-9.00-8.001
-8.00-7.004
-7.00-6.004
-6.00-5.008
-5.00-4.006
-4.00-3.001
-3.00-2.002
-2.00-1.000
-1.00+0.002
+0.00+1.000
+1.00+2.000
+2.00+3.000
+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
2026-08295.32 -5.32

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29

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
Aurora (GFS init) 1 -2.29 [-2.29, -2.29] yes
Aurora (IFS init) 2 +0.42 [0.07, 0.76] yes
FourCastNet v2 (GFS init) 1 +0.48 [0.48, 0.48] yes
FourCastNet v2 (IFS init) 2 +2.62 [2.09, 3.16] yes
NCEP GFS 29 +1.04 [-0.61, 2.85] no
GraphCast (GFS init) 1 -2.21 [-2.21, -2.21] yes
GraphCast (IFS init) 27 +0.81 [-0.29, 1.47] no
ECMWF IFS HRES 22 +3.21 [1.64, 4.10] yes
Pangu-Weather (GFS init) 1 -0.20 [-0.20, -0.20] yes
Pangu-Weather (IFS init) 2 +1.26 [0.54, 1.99] yes
Persistence (baseline) 29 +2.21 [0.61, 3.64] yes

Cite this page

ShortCastCheck, KSEA aifs_single lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSEA/model/aifs_single/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSEA (Seattle-Tacoma), model aifs_single, lead day 1. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSEA/model/aifs_single/lead/1/

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

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