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

San Antonio Intl · NCEP GFS · lead day 1

KSAT · gfs · 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, 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
tmax00Zbilinear30d29 1 QC1.76 [1.18, 2.46]1.46-1.45 [-2.22, -0.73]2.32 [1.43, 3.08]45% [30%, 62%]72%76%-0.71-0.382026-08-02 → 2026-08-30
tmax00Zbilinear90d29 1 QC1.76 [1.11, 2.71]1.46-1.45 [-2.53, -0.59]2.32 [1.38, 3.30]45% [25%, 65%]72%76%-0.71-0.382026-08-02 → 2026-08-30
tmax00Zbilinear365d29 1 QC1.76 [1.06, 2.86]1.46-1.45 [-2.68, -0.54]2.32 [1.30, 3.43]45% [23%, 67%]72%76%-0.71-0.382026-08-02 → 2026-08-30
tmax00Zbilinearall29 1 QC1.76 [1.09, 2.69]1.46-1.45 [-2.52, -0.58]2.32 [1.33, 3.29]45% [27%, 67%]72%76%-0.71-0.382026-08-02 → 2026-08-30
tmax00Znearest30d29 1 QC1.72 [1.14, 2.43]1.55-1.25 [-2.08, -0.44]2.29 [1.39, 3.12]48% [36%, 63%]72%79%-0.66-0.472026-08-02 → 2026-08-30
tmax00Znearest90d29 1 QC1.72 [1.12, 2.76]1.55-1.25 [-2.44, -0.31]2.29 [1.35, 3.39]48% [29%, 65%]72%79%-0.66-0.472026-08-02 → 2026-08-30
tmax00Znearest365d29 1 QC1.72 [1.09, 2.83]1.55-1.25 [-2.62, -0.28]2.29 [1.27, 3.47]48% [30%, 67%]72%79%-0.66-0.472026-08-02 → 2026-08-30
tmax00Znearestall29 1 QC1.72 [1.11, 2.69]1.55-1.25 [-2.44, -0.30]2.29 [1.32, 3.35]48% [33%, 66%]72%79%-0.66-0.472026-08-02 → 2026-08-30
tmax12Zbilinear30d29 1 QC1.65 [1.19, 2.14]1.37-1.31 [-1.89, -0.75]2.15 [1.50, 2.67]45% [28%, 61%]62%86%-0.59-0.302026-08-02 → 2026-08-30
tmax12Zbilinear90d29 1 QC1.65 [1.14, 2.36]1.37-1.31 [-2.10, -0.66]2.15 [1.41, 2.86]45% [24%, 64%]62%86%-0.59-0.302026-08-02 → 2026-08-30
tmax12Zbilinear365d29 1 QC1.65 [1.11, 2.40]1.37-1.31 [-2.15, -0.61]2.15 [1.37, 2.86]45% [21%, 67%]62%86%-0.59-0.302026-08-02 → 2026-08-30
tmax12Zbilinearall29 1 QC1.65 [1.08, 2.34]1.37-1.31 [-2.09, -0.62]2.15 [1.37, 2.87]45% [22%, 67%]62%86%-0.59-0.302026-08-02 → 2026-08-30
tmax12Znearest30d29 1 QC1.58 [1.13, 2.05]1.39-1.13 [-1.72, -0.57]2.07 [1.42, 2.58]45% [33%, 57%]62%86%-0.52-0.322026-08-02 → 2026-08-30
tmax12Znearest90d29 1 QC1.58 [1.09, 2.24]1.39-1.13 [-1.93, -0.49]2.07 [1.36, 2.72]45% [28%, 59%]62%86%-0.52-0.322026-08-02 → 2026-08-30
tmax12Znearest365d29 1 QC1.58 [1.07, 2.27]1.39-1.13 [-2.01, -0.45]2.07 [1.31, 2.74]45% [26%, 60%]62%86%-0.52-0.322026-08-02 → 2026-08-30
tmax12Znearestall29 1 QC1.58 [1.08, 2.24]1.39-1.13 [-1.89, -0.44]2.07 [1.31, 2.75]45% [28%, 61%]62%86%-0.52-0.322026-08-02 → 2026-08-30
tmin00Zbilinear30d29 1 QC1.96 [1.60, 2.38]1.89-0.37 [-1.83, 1.10]2.39 [1.92, 2.79]34% [17%, 50%]55%79%-0.32-0.272026-08-02 → 2026-08-30
tmin00Zbilinear90d29 1 QC1.96 [1.57, 2.43]1.89-0.37 [-1.88, 1.33]2.39 [1.82, 2.88]34% [14%, 53%]55%79%-0.32-0.272026-08-02 → 2026-08-30
tmin00Zbilinear365d29 1 QC1.96 [1.55, 2.42]1.89-0.37 [-1.92, 1.51]2.39 [1.81, 2.90]34% [11%, 54%]55%79%-0.32-0.272026-08-02 → 2026-08-30
tmin00Zbilinearall29 1 QC1.96 [1.54, 2.42]1.89-0.37 [-1.89, 1.27]2.39 [1.81, 2.83]34% [14%, 57%]55%79%-0.32-0.272026-08-02 → 2026-08-30
tmin00Znearest30d29 1 QC1.93 [1.47, 2.40]1.94+0.08 [-1.40, 1.60]2.42 [1.78, 3.02]28% [10%, 43%]62%79%-0.30-0.302026-08-02 → 2026-08-30
tmin00Znearest90d29 1 QC1.93 [1.46, 2.48]1.94+0.08 [-1.46, 1.85]2.42 [1.75, 3.13]28% [8%, 44%]62%79%-0.30-0.302026-08-02 → 2026-08-30
tmin00Znearest365d29 1 QC1.93 [1.45, 2.53]1.94+0.08 [-1.50, 2.03]2.42 [1.76, 3.19]28% [7%, 44%]62%79%-0.30-0.302026-08-02 → 2026-08-30
tmin00Znearestall29 1 QC1.93 [1.43, 2.46]1.94+0.08 [-1.50, 1.75]2.42 [1.76, 3.08]28% [5%, 46%]62%79%-0.30-0.302026-08-02 → 2026-08-30
tmin12Zbilinear30d29 1 QC1.88 [1.57, 2.25]1.79-0.42 [-1.82, 1.00]2.29 [1.91, 2.65]28% [13%, 40%]55%86%-0.27-0.202026-08-02 → 2026-08-30
tmin12Zbilinear90d29 1 QC1.88 [1.57, 2.25]1.79-0.42 [-1.81, 1.17]2.29 [1.84, 2.72]28% [12%, 42%]55%86%-0.27-0.202026-08-02 → 2026-08-30
tmin12Zbilinear365d29 1 QC1.88 [1.56, 2.28]1.79-0.42 [-1.91, 1.28]2.29 [1.83, 2.71]28% [10%, 43%]55%86%-0.27-0.202026-08-02 → 2026-08-30
tmin12Zbilinearall29 1 QC1.88 [1.51, 2.29]1.79-0.42 [-1.85, 1.20]2.29 [1.82, 2.68]28% [9%, 43%]55%86%-0.27-0.202026-08-02 → 2026-08-30
tmin12Znearest30d29 1 QC1.82 [1.45, 2.18]1.82+0.03 [-1.40, 1.47]2.30 [1.76, 2.77]34% [21%, 47%]62%83%-0.23-0.222026-08-02 → 2026-08-30
tmin12Znearest90d29 1 QC1.82 [1.45, 2.20]1.82+0.03 [-1.40, 1.66]2.30 [1.74, 2.88]34% [22%, 50%]62%83%-0.23-0.222026-08-02 → 2026-08-30
tmin12Znearest365d29 1 QC1.82 [1.44, 2.23]1.82+0.03 [-1.49, 1.77]2.30 [1.73, 2.93]34% [21%, 50%]62%83%-0.23-0.222026-08-02 → 2026-08-30
tmin12Znearestall29 1 QC1.82 [1.42, 2.19]1.82+0.03 [-1.43, 1.67]2.30 [1.72, 2.81]34% [21%, 50%]62%83%-0.23-0.222026-08-02 → 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 NCEP GFS at KSAT, lead day 1, 00Z bilinear tmax+10+50-5-102026-08-02: +0.6 °F2026-08-03: +0.25 °F2026-08-04: -2.36 °F2026-08-05: +0.99 °F2026-08-06: -0.1 °F2026-08-07: -0.89 °F2026-08-08: +1.1 °F2026-08-09: +0.24 °F2026-08-10: -4.23 °F2026-08-11: -1.48 °F2026-08-12: -3.24 °F2026-08-13: -3.95 °F2026-08-14: -0.9 °F2026-08-15: -1.05 °F2026-08-16: +0.9 °F2026-08-17: -0.12 °F2026-08-18: -1 °F2026-08-19: -1.94 °F2026-08-20: -0.97 °F2026-08-21: -1.78 °F2026-08-22: -1.88 °F2026-08-23: -1.78 °F2026-08-24: -1.02 °F2026-08-25: -0.54 °F2026-08-26: +0.43 °F2026-08-27: -3.64 °F2026-08-28: -4.93 °F2026-08-29: -5.83 °F2026-08-30: -3.03 °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
2026-08-30-3.03
2026-08-29-5.83
2026-08-28-4.93
2026-08-27-3.64
2026-08-26+0.43
2026-08-25-0.54
2026-08-24-1.02
2026-08-23-1.78
2026-08-22-1.88
2026-08-21-1.78
2026-08-20-0.97
2026-08-19-1.94
2026-08-18-1.00
2026-08-17-0.12
2026-08-16+0.90
2026-08-15-1.05
2026-08-14-0.90
2026-08-13-3.95
2026-08-12-3.24
2026-08-11-1.48
2026-08-10-4.23
2026-08-09+0.24
2026-08-08+1.10
2026-08-07-0.89
2026-08-06-0.10
2026-08-05+0.99
2026-08-04-2.36
2026-08-03+0.25
2026-08-02+0.60

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAT, lead day 1-10 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: 1 day-5 to -4 °F: 2 days-4 to -3 °F: 4 days-3 to -2 °F: 1 day-2 to -1 °F: 7 days-1 to 0 °F: 7 days0 to 1 °F: 6 days1 to 2 °F: 1 day2 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| 1.05 · P90 |e| 4.01 °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
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.001
-5.00-4.002
-4.00-3.004
-3.00-2.001
-2.00-1.007
-1.00+0.007
+0.00+1.006
+1.00+2.001
+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
2026-08291.76 -1.45

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 29 -1.35 [-2.02, -0.51] yes
Aurora (GFS init) 1 -4.79 [-4.79, -4.79] yes
Aurora (IFS init) 2 -1.63 [-3.12, -0.13] yes
FourCastNet v2 (GFS init) 1 -0.77 [-0.77, -0.77] yes
FourCastNet v2 (IFS init) 2 +1.70 [0.38, 3.02] yes
GraphCast (GFS init) 1 -4.49 [-4.49, -4.49] yes
GraphCast (IFS init) 27 -4.14 [-4.68, -3.36] yes
ECMWF IFS HRES 23 -1.19 [-2.31, 0.11] no
Pangu-Weather (GFS init) 1 -0.14 [-0.14, -0.14] yes
Pangu-Weather (IFS init) 2 +0.48 [-0.65, 1.61] no
Persistence (baseline) 29 +0.73 [0.17, 1.59] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAT (San Antonio Intl), model gfs, 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/KSAT/model/gfs/lead/1/

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

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