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

San Antonio Intl · NCEP GFS · lead day 9

KSAT · gfs · lead 9

Target day = initialization date + 9 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, gfs-0p25, 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
tmax00Zbilinear30d21 1 QC2.41 [1.59, 3.29]2.21-0.74 [-2.24, 1.03]3.15 [1.73, 4.28]14% [4%, 27%]48%81%-0.12-0.282026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC2.41 [1.48, 3.39]2.21-0.74 [-2.36, 1.50]3.15 [1.60, 4.31]14% [0%, 31%]48%81%-0.12-0.282026-08-10 → 2026-08-30
tmax00Zbilinear365d21 1 QC2.41 [1.48, 3.41]2.21-0.74 [-2.52, 1.54]3.15 [1.60, 4.38]14% [0%, 30%]48%81%-0.12-0.282026-08-10 → 2026-08-30
tmax00Zbilinearall21 1 QC2.41 [1.50, 3.43]2.21-0.74 [-2.66, 1.78]3.15 [1.63, 4.39]14% [0%, 29%]48%81%-0.12-0.282026-08-10 → 2026-08-30
tmax00Znearest30d21 1 QC2.34 [1.49, 3.24]2.21-0.56 [-2.03, 1.21]3.09 [1.70, 4.17]19% [5%, 33%]52%76%-0.09-0.282026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC2.34 [1.32, 3.41]2.21-0.56 [-2.14, 1.66]3.09 [1.51, 4.18]19% [0%, 38%]52%76%-0.09-0.282026-08-10 → 2026-08-30
tmax00Znearest365d21 1 QC2.34 [1.33, 3.55]2.21-0.56 [-2.34, 1.66]3.09 [1.53, 4.24]19% [0%, 37%]52%76%-0.09-0.282026-08-10 → 2026-08-30
tmax00Znearestall21 1 QC2.34 [1.37, 3.58]2.21-0.56 [-2.45, 1.93]3.09 [1.56, 4.22]19% [0%, 38%]52%76%-0.09-0.282026-08-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC2.07 [0.96, 3.40]2.04-0.16 [-1.72, 1.71]2.78 [1.26, 3.88]38% [11%, 59%]67%71%+0.04-0.182026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC2.07 [0.94, 3.62]2.04-0.16 [-1.80, 2.14]2.78 [1.20, 3.98]38% [0%, 58%]67%71%+0.04-0.182026-08-10 → 2026-08-30
tmax12Zbilinear365d21 1 QC2.07 [0.92, 3.65]2.04-0.16 [-1.92, 2.16]2.78 [1.20, 4.00]38% [0%, 62%]67%71%+0.04-0.182026-08-10 → 2026-08-30
tmax12Zbilinearall21 1 QC2.07 [0.92, 3.59]2.04-0.16 [-2.27, 2.43]2.78 [1.21, 3.94]38% [0%, 58%]67%71%+0.04-0.182026-08-10 → 2026-08-30
tmax12Znearest30d21 1 QC2.04 [0.96, 3.40]2.04+0.02 [-1.58, 1.90]2.81 [1.37, 3.91]38% [11%, 59%]67%67%+0.05-0.192026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC2.04 [0.92, 3.64]2.04+0.02 [-1.65, 2.30]2.81 [1.30, 4.02]38% [0%, 58%]67%67%+0.05-0.192026-08-10 → 2026-08-30
tmax12Znearest365d21 1 QC2.04 [0.92, 3.72]2.04+0.02 [-1.79, 2.37]2.81 [1.30, 4.05]38% [0%, 62%]67%67%+0.05-0.192026-08-10 → 2026-08-30
tmax12Znearestall21 1 QC2.04 [0.92, 3.75]2.04+0.02 [-2.11, 2.64]2.81 [1.33, 4.02]38% [0%, 58%]67%67%+0.05-0.192026-08-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC2.07 [1.54, 2.66]1.66-1.08 [-2.62, 0.54]2.44 [1.81, 2.94]19% [6%, 31%]57%76%-0.15+0.062026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC2.07 [1.49, 2.68]1.66-1.08 [-2.67, 0.96]2.44 [1.79, 2.95]19% [0%, 33%]57%76%-0.15+0.062026-08-10 → 2026-08-30
tmin00Zbilinear365d21 1 QC2.07 [1.46, 2.68]1.66-1.08 [-2.68, 1.06]2.44 [1.66, 2.94]19% [0%, 33%]57%76%-0.15+0.062026-08-10 → 2026-08-30
tmin00Zbilinearall21 1 QC2.07 [1.35, 2.68]1.66-1.08 [-2.68, 0.95]2.44 [1.48, 2.95]19% [0%, 33%]57%76%-0.15+0.062026-08-10 → 2026-08-30
tmin00Znearest30d21 1 QC1.90 [1.44, 2.38]1.67-0.65 [-2.22, 0.99]2.30 [1.62, 2.86]24% [10%, 35%]62%90%-0.05+0.062026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC1.90 [1.40, 2.38]1.67-0.65 [-2.29, 1.40]2.30 [1.55, 2.92]24% [0%, 36%]62%90%-0.05+0.062026-08-10 → 2026-08-30
tmin00Znearest365d21 1 QC1.90 [1.35, 2.44]1.67-0.65 [-2.29, 1.51]2.30 [1.51, 2.88]24% [0%, 36%]62%90%-0.05+0.062026-08-10 → 2026-08-30
tmin00Znearestall21 1 QC1.90 [1.29, 2.41]1.67-0.65 [-2.27, 1.40]2.30 [1.38, 2.84]24% [0%, 35%]62%90%-0.05+0.062026-08-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC2.46 [1.80, 3.08]2.28-0.73 [-2.43, 1.23]2.83 [2.11, 3.55]14% [0%, 33%]43%76%-0.36-0.292026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC2.46 [1.78, 3.20]2.28-0.73 [-2.90, 1.79]2.83 [2.07, 3.66]14% [0%, 37%]43%76%-0.36-0.292026-08-10 → 2026-08-30
tmin12Zbilinear365d21 1 QC2.46 [1.71, 3.16]2.28-0.73 [-2.76, 1.87]2.83 [1.98, 3.63]14% [0%, 38%]43%76%-0.36-0.292026-08-10 → 2026-08-30
tmin12Zbilinearall21 1 QC2.46 [1.50, 3.16]2.28-0.73 [-2.74, 1.84]2.83 [1.73, 3.61]14% [0%, 43%]43%76%-0.36-0.292026-08-10 → 2026-08-30
tmin12Znearest30d21 1 QC2.38 [1.69, 3.09]2.30-0.31 [-2.06, 1.68]2.81 [1.86, 3.77]14% [0%, 33%]48%86%-0.31-0.302026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC2.38 [1.70, 3.22]2.30-0.31 [-2.52, 2.25]2.81 [1.83, 3.93]14% [0%, 37%]48%86%-0.31-0.302026-08-10 → 2026-08-30
tmin12Znearest365d21 1 QC2.38 [1.64, 3.20]2.30-0.31 [-2.38, 2.31]2.81 [1.77, 3.94]14% [0%, 38%]48%86%-0.31-0.302026-08-10 → 2026-08-30
tmin12Znearestall21 1 QC2.38 [1.46, 3.20]2.30-0.31 [-2.36, 2.29]2.81 [1.61, 3.91]14% [0%, 43%]48%86%-0.31-0.302026-08-10 → 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 NCEP GFS at KSAT, lead day 9, 00Z bilinear tmax+20+100-10-202026-08-10: -0.93 °F2026-08-11: -1.41 °F2026-08-12: -1.38 °F2026-08-13: -1.11 °F2026-08-14: +2.61 °F2026-08-15: -2.2 °F2026-08-16: +2.35 °F2026-08-17: -0.54 °F2026-08-18: +1.29 °F2026-08-19: -2.05 °F2026-08-20: -1.57 °F2026-08-21: -0.45 °F2026-08-22: -3.03 °F2026-08-23: -10.21 °F2026-08-24: -2.91 °F2026-08-25: -1.47 °F2026-08-26: +1.01 °F2026-08-27: -3.82 °F2026-08-28: +2.89 °F2026-08-29: +2.87 °F2026-08-30: +4.49 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+4.49
2026-08-29+2.87
2026-08-28+2.89
2026-08-27-3.82
2026-08-26+1.01
2026-08-25-1.47
2026-08-24-2.91
2026-08-23-10.21
2026-08-22-3.03
2026-08-21-0.45
2026-08-20-1.57
2026-08-19-2.05
2026-08-18+1.29
2026-08-17-0.54
2026-08-16+2.35
2026-08-15-2.20
2026-08-14+2.61
2026-08-13-1.11
2026-08-12-1.38
2026-08-11-1.41
2026-08-10-0.93

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAT, lead day 9-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 1 day-10 to -8 °F: 0 days-8 to -6 °F: 0 days-6 to -4 °F: 0 days-4 to -2 °F: 5 days-2 to 0 °F: 8 days0 to 2 °F: 2 days2 to 4 °F: 4 days4 to 6 °F: 1 day6 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| 2.05 · P90 |e| 3.82 °F-200+20 °Fn = 21 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
-14.00-12.000
-12.00-10.001
-10.00-8.000
-8.00-6.000
-6.00-4.000
-4.00-2.005
-2.00+0.008
+0.00+2.002
+2.00+4.004
+4.00+6.001
+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
2026-08212.41 -0.74

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-10 → 2026-08-30 21
NCEP GFS2026-08-10 → 2026-08-30 21
NCEP GFS2026-08-10 → 2026-08-30 21
NCEP GFS2026-08-10 → 2026-08-30 21

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means NCEP GFS has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 21 -0.73 [-1.78, 1.12] no
GraphCast (IFS init) 21 -3.75 [-4.63, -1.80] yes
ECMWF IFS HRES 16 -0.39 [-1.68, 0.85] no
Persistence (baseline) 21 +0.27 [-0.47, 1.01] no

Cite this page

ShortCastCheck, KSAT gfs lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAT/model/gfs/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAT (San Antonio Intl), model gfs, lead day 9. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSAT/model/gfs/lead/9/

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