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

Seattle-Tacoma · ECMWF AIFS Single · lead day 7

KSEA · aifs_single · lead 7

Target day = initialization date + 7 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
tmax00Zbilinear30d23 1 QC5.78 [3.00, 8.02]4.24-5.32 [-7.91, -2.08]7.20 [4.03, 9.07]13% [0%, 31%]26%39%-0.16+0.142026-08-08 → 2026-08-30
tmax00Zbilinear90d23 1 QC5.78 [2.69, 8.32]4.24-5.32 [-8.21, -1.62]7.20 [3.44, 9.28]13% [0%, 33%]26%39%-0.16+0.142026-08-08 → 2026-08-30
tmax00Zbilinear365d23 1 QC5.78 [2.60, 8.78]4.24-5.32 [-8.78, -1.72]7.20 [3.44, 9.58]13% [0%, 33%]26%39%-0.16+0.142026-08-08 → 2026-08-30
tmax00Zbilinearall23 1 QC5.78 [2.62, 8.46]4.24-5.32 [-8.43, -1.60]7.20 [3.27, 9.41]13% [0%, 34%]26%39%-0.16+0.142026-08-08 → 2026-08-30
tmax00Znearest30d23 1 QC5.58 [2.92, 7.78]4.25-5.01 [-7.60, -1.73]6.99 [3.89, 8.87]17% [0%, 36%]22%43%-0.12+0.142026-08-08 → 2026-08-30
tmax00Znearest90d23 1 QC5.58 [2.59, 8.00]4.25-5.01 [-7.90, -1.28]6.99 [3.35, 9.00]17% [0%, 38%]22%43%-0.12+0.142026-08-08 → 2026-08-30
tmax00Znearest365d23 1 QC5.58 [2.55, 8.48]4.25-5.01 [-8.46, -1.38]6.99 [3.35, 9.30]17% [0%, 39%]22%43%-0.12+0.142026-08-08 → 2026-08-30
tmax00Znearestall23 1 QC5.58 [2.56, 8.22]4.25-5.01 [-8.17, -1.32]6.99 [3.18, 9.20]17% [0%, 39%]22%43%-0.12+0.142026-08-08 → 2026-08-30
tmax12Zbilinear30d23 1 QC5.48 [3.19, 7.77]3.85-5.04 [-7.66, -2.37]6.87 [3.91, 9.09]4% [0%, 12%]17%43%-0.10+0.222026-08-08 → 2026-08-30
tmax12Zbilinear90d23 1 QC5.48 [2.89, 7.89]3.85-5.04 [-7.82, -1.83]6.87 [3.45, 9.17]4% [0%, 13%]17%43%-0.10+0.222026-08-08 → 2026-08-30
tmax12Zbilinear365d23 1 QC5.48 [2.76, 8.37]3.85-5.04 [-8.13, -1.72]6.87 [3.31, 9.59]4% [0%, 13%]17%43%-0.10+0.222026-08-08 → 2026-08-30
tmax12Zbilinearall23 1 QC5.48 [2.76, 7.94]3.85-5.04 [-7.86, -1.88]6.87 [3.32, 9.29]4% [0%, 14%]17%43%-0.10+0.222026-08-08 → 2026-08-30
tmax12Znearest30d23 1 QC5.29 [3.08, 7.54]3.87-4.72 [-7.36, -2.04]6.67 [3.77, 8.85]13% [0%, 30%]26%43%-0.06+0.222026-08-08 → 2026-08-30
tmax12Znearest90d23 1 QC5.29 [2.77, 7.61]3.87-4.72 [-7.49, -1.48]6.67 [3.28, 8.92]13% [0%, 31%]26%43%-0.06+0.222026-08-08 → 2026-08-30
tmax12Znearest365d23 1 QC5.29 [2.62, 8.07]3.87-4.72 [-7.83, -1.46]6.67 [3.20, 9.32]13% [0%, 33%]26%43%-0.06+0.222026-08-08 → 2026-08-30
tmax12Znearestall23 1 QC5.29 [2.63, 7.69]3.87-4.72 [-7.57, -1.51]6.67 [3.23, 9.03]13% [0%, 33%]26%43%-0.06+0.222026-08-08 → 2026-08-30
tmin00Zbilinear30d23 1 QC1.86 [1.51, 2.19]1.61+0.79 [-0.43, 1.73]2.28 [1.84, 2.60]35% [18%, 50%]65%78%+0.18+0.292026-08-08 → 2026-08-30
tmin00Zbilinear90d23 1 QC1.86 [1.49, 2.23]1.61+0.79 [-0.86, 1.87]2.28 [1.71, 2.65]35% [14%, 50%]65%78%+0.18+0.292026-08-08 → 2026-08-30
tmin00Zbilinear365d23 1 QC1.86 [1.43, 2.25]1.61+0.79 [-0.77, 1.85]2.28 [1.70, 2.66]35% [12%, 51%]65%78%+0.18+0.292026-08-08 → 2026-08-30
tmin00Zbilinearall23 1 QC1.86 [1.40, 2.21]1.61+0.79 [-1.12, 1.89]2.28 [1.62, 2.65]35% [0%, 55%]65%78%+0.18+0.292026-08-08 → 2026-08-30
tmin00Znearest30d23 1 QC1.88 [1.54, 2.21]1.60+0.87 [-0.29, 1.72]2.30 [1.89, 2.62]22% [9%, 32%]65%78%+0.17+0.292026-08-08 → 2026-08-30
tmin00Znearest90d23 1 QC1.88 [1.50, 2.22]1.60+0.87 [-0.77, 1.82]2.30 [1.79, 2.66]22% [8%, 33%]65%78%+0.17+0.292026-08-08 → 2026-08-30
tmin00Znearest365d23 1 QC1.88 [1.48, 2.25]1.60+0.87 [-0.65, 1.81]2.30 [1.74, 2.66]22% [0%, 33%]65%78%+0.17+0.292026-08-08 → 2026-08-30
tmin00Znearestall23 1 QC1.88 [1.45, 2.23]1.60+0.87 [-1.03, 1.87]2.30 [1.63, 2.63]22% [0%, 33%]65%78%+0.17+0.292026-08-08 → 2026-08-30
tmin12Zbilinear30d23 1 QC1.59 [1.30, 1.81]1.61+0.34 [-0.84, 1.44]1.92 [1.62, 2.14]43% [33%, 58%]57%87%+0.30+0.292026-08-08 → 2026-08-30
tmin12Zbilinear90d23 1 QC1.59 [1.25, 1.84]1.61+0.34 [-1.03, 1.53]1.92 [1.57, 2.17]43% [31%, 60%]57%87%+0.30+0.292026-08-08 → 2026-08-30
tmin12Zbilinear365d23 1 QC1.59 [1.22, 1.84]1.61+0.34 [-1.05, 1.52]1.92 [1.58, 2.16]43% [30%, 60%]57%87%+0.30+0.292026-08-08 → 2026-08-30
tmin12Zbilinearall23 1 QC1.59 [1.20, 1.85]1.61+0.34 [-1.07, 1.55]1.92 [1.55, 2.18]43% [30%, 67%]57%87%+0.30+0.292026-08-08 → 2026-08-30
tmin12Znearest30d23 1 QC1.61 [1.26, 1.86]1.62+0.42 [-0.72, 1.46]1.95 [1.64, 2.15]43% [33%, 58%]61%91%+0.29+0.282026-08-08 → 2026-08-30
tmin12Znearest90d23 1 QC1.61 [1.19, 1.88]1.62+0.42 [-0.90, 1.55]1.95 [1.59, 2.18]43% [31%, 60%]61%91%+0.29+0.282026-08-08 → 2026-08-30
tmin12Znearest365d23 1 QC1.61 [1.12, 1.90]1.62+0.42 [-0.92, 1.53]1.95 [1.53, 2.18]43% [30%, 60%]61%91%+0.29+0.282026-08-08 → 2026-08-30
tmin12Znearestall23 1 QC1.61 [1.11, 1.89]1.62+0.42 [-0.93, 1.57]1.95 [1.50, 2.19]43% [30%, 67%]61%91%+0.29+0.282026-08-08 → 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 7, 00Z bilinear tmax+20+100-10-202026-08-08: -3.24 °F2026-08-09: -0.34 °F2026-08-10: +1.65 °F2026-08-11: +0.27 °F2026-08-12: -7.73 °F2026-08-13: -7.71 °F2026-08-14: +2.04 °F2026-08-15: -0.9 °F2026-08-16: -1.4 °F2026-08-17: -7.86 °F2026-08-18: -9.53 °F2026-08-19: -12.76 °F2026-08-20: -13.71 °F2026-08-21: -8.52 °F2026-08-22: -8 °F2026-08-23: -2.92 °F2026-08-24: -7.87 °F2026-08-25: -14.46 °F2026-08-26: -9.1 °F2026-08-27: -3.99 °F2026-08-28: -2.23 °F2026-08-29: -5.38 °F2026-08-30: +1.28 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+1.28
2026-08-29-5.38
2026-08-28-2.23
2026-08-27-3.99
2026-08-26-9.10
2026-08-25-14.46
2026-08-24-7.87
2026-08-23-2.92
2026-08-22-8.00
2026-08-21-8.52
2026-08-20-13.71
2026-08-19-12.76
2026-08-18-9.53
2026-08-17-7.86
2026-08-16-1.40
2026-08-15-0.90
2026-08-14+2.04
2026-08-13-7.71
2026-08-12-7.73
2026-08-11+0.27
2026-08-10+1.65
2026-08-09-0.34
2026-08-08-3.24

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KSEA, lead day 7-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 1 day-14 to -12 °F: 2 days-12 to -10 °F: 0 days-10 to -8 °F: 4 days-8 to -6 °F: 4 days-6 to -4 °F: 1 day-4 to -2 °F: 4 days-2 to 0 °F: 3 days0 to 2 °F: 3 days2 to 4 °F: 1 day4 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| 5.38 · P90 |e| 12.11 °F-200+20 °Fn = 23 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
-16.00-14.001
-14.00-12.002
-12.00-10.000
-10.00-8.004
-8.00-6.004
-6.00-4.001
-4.00-2.004
-2.00+0.003
+0.00+2.003
+2.00+4.001
+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
2026-08235.78 -5.32

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23

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 23 +1.12 [-2.92, 4.66] no
GraphCast (IFS init) 23 -0.67 [-3.00, 0.47] no
ECMWF IFS HRES 18 +1.68 [-1.85, 3.37] no
Persistence (baseline) 23 +0.78 [-3.85, 4.63] no

Cite this page

ShortCastCheck, KSEA aifs_single lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSEA/model/aifs_single/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSEA (Seattle-Tacoma), model aifs_single, lead day 7. 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/7/

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