Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

San Antonio Intl · NCEP GFS · lead day 2

KSAT · gfs · lead 2

Target day = initialization date + 2 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
tmax00Zbilinear30d28 1 QC1.77 [1.26, 2.23]1.54-1.39 [-1.90, -0.75]2.34 [1.71, 2.85]46% [28%, 70%]68%82%-0.21-0.042026-08-03 → 2026-08-30
tmax00Zbilinear90d28 1 QC1.77 [1.20, 2.22]1.54-1.39 [-1.86, -0.69]2.34 [1.56, 2.84]46% [25%, 71%]68%82%-0.21-0.042026-08-03 → 2026-08-30
tmax00Zbilinear365d28 1 QC1.77 [1.17, 2.23]1.54-1.39 [-1.90, -0.57]2.34 [1.50, 2.86]46% [23%, 71%]68%82%-0.21-0.042026-08-03 → 2026-08-30
tmax00Zbilinearall28 1 QC1.77 [1.20, 2.21]1.54-1.39 [-1.88, -0.64]2.34 [1.62, 2.83]46% [24%, 69%]68%82%-0.21-0.042026-08-03 → 2026-08-30
tmax00Znearest30d28 1 QC1.69 [1.16, 2.17]1.55-1.19 [-1.68, -0.54]2.26 [1.62, 2.75]39% [21%, 59%]68%82%-0.15-0.042026-08-03 → 2026-08-30
tmax00Znearest90d28 1 QC1.69 [1.08, 2.18]1.55-1.19 [-1.64, -0.47]2.26 [1.46, 2.75]39% [18%, 60%]68%82%-0.15-0.042026-08-03 → 2026-08-30
tmax00Znearest365d28 1 QC1.69 [1.06, 2.18]1.55-1.19 [-1.68, -0.40]2.26 [1.35, 2.77]39% [17%, 61%]68%82%-0.15-0.042026-08-03 → 2026-08-30
tmax00Znearestall28 1 QC1.69 [1.12, 2.17]1.55-1.19 [-1.65, -0.46]2.26 [1.53, 2.75]39% [18%, 59%]68%82%-0.15-0.042026-08-03 → 2026-08-30
tmax12Zbilinear30d28 1 QC1.65 [1.19, 2.09]1.27-1.31 [-1.85, -0.77]2.07 [1.49, 2.51]36% [21%, 50%]75%82%-0.12+0.142026-08-03 → 2026-08-30
tmax12Zbilinear90d28 1 QC1.65 [1.14, 2.10]1.27-1.31 [-1.90, -0.63]2.07 [1.39, 2.52]36% [21%, 53%]75%82%-0.12+0.142026-08-03 → 2026-08-30
tmax12Zbilinear365d28 1 QC1.65 [1.04, 2.17]1.27-1.31 [-1.95, -0.54]2.07 [1.20, 2.58]36% [20%, 55%]75%82%-0.12+0.142026-08-03 → 2026-08-30
tmax12Zbilinearall28 1 QC1.65 [1.10, 2.17]1.27-1.31 [-1.96, -0.59]2.07 [1.25, 2.58]36% [20%, 53%]75%82%-0.12+0.142026-08-03 → 2026-08-30
tmax12Znearest30d28 1 QC1.53 [1.09, 1.95]1.26-1.05 [-1.53, -0.53]1.87 [1.37, 2.28]39% [23%, 54%]75%86%-0.04+0.152026-08-03 → 2026-08-30
tmax12Znearest90d28 1 QC1.53 [1.07, 1.96]1.26-1.05 [-1.55, -0.42]1.87 [1.30, 2.30]39% [22%, 55%]75%86%-0.04+0.152026-08-03 → 2026-08-30
tmax12Znearest365d28 1 QC1.53 [1.00, 2.01]1.26-1.05 [-1.64, -0.34]1.87 [1.21, 2.34]39% [21%, 57%]75%86%-0.04+0.152026-08-03 → 2026-08-30
tmax12Znearestall28 1 QC1.53 [1.04, 2.01]1.26-1.05 [-1.63, -0.33]1.87 [1.24, 2.36]39% [23%, 57%]75%86%-0.04+0.152026-08-03 → 2026-08-30
tmin00Zbilinear30d28 1 QC2.11 [1.69, 2.62]1.85-0.66 [-1.73, 0.49]2.43 [1.99, 2.99]18% [4%, 34%]54%82%-0.31-0.132026-08-03 → 2026-08-30
tmin00Zbilinear90d28 1 QC2.11 [1.65, 2.73]1.85-0.66 [-1.80, 0.79]2.43 [1.97, 3.10]18% [0%, 36%]54%82%-0.31-0.132026-08-03 → 2026-08-30
tmin00Zbilinear365d28 1 QC2.11 [1.65, 2.79]1.85-0.66 [-1.87, 0.86]2.43 [1.98, 3.17]18% [0%, 36%]54%82%-0.31-0.132026-08-03 → 2026-08-30
tmin00Zbilinearall28 1 QC2.11 [1.65, 2.71]1.85-0.66 [-1.85, 0.73]2.43 [1.97, 3.07]18% [0%, 36%]54%82%-0.31-0.132026-08-03 → 2026-08-30
tmin00Znearest30d28 1 QC1.93 [1.48, 2.55]1.87-0.21 [-1.31, 0.98]2.39 [1.75, 3.13]21% [7%, 37%]68%82%-0.20-0.152026-08-03 → 2026-08-30
tmin00Znearest90d28 1 QC1.93 [1.46, 2.70]1.87-0.21 [-1.39, 1.28]2.39 [1.72, 3.28]21% [7%, 39%]68%82%-0.20-0.152026-08-03 → 2026-08-30
tmin00Znearest365d28 1 QC1.93 [1.46, 2.80]1.87-0.21 [-1.46, 1.34]2.39 [1.73, 3.37]21% [5%, 40%]68%82%-0.20-0.152026-08-03 → 2026-08-30
tmin00Znearestall28 1 QC1.93 [1.47, 2.68]1.87-0.21 [-1.44, 1.21]2.39 [1.71, 3.23]21% [4%, 40%]68%82%-0.20-0.152026-08-03 → 2026-08-30
tmin12Zbilinear30d28 1 QC2.10 [1.75, 2.53]1.88-0.51 [-1.80, 0.87]2.51 [2.05, 3.11]25% [10%, 40%]57%79%-0.30-0.152026-08-03 → 2026-08-30
tmin12Zbilinear90d28 1 QC2.10 [1.72, 2.65]1.88-0.51 [-1.83, 1.21]2.51 [2.02, 3.23]25% [9%, 41%]57%79%-0.30-0.152026-08-03 → 2026-08-30
tmin12Zbilinear365d28 1 QC2.10 [1.70, 2.66]1.88-0.51 [-1.92, 1.26]2.51 [2.04, 3.25]25% [7%, 43%]57%79%-0.30-0.152026-08-03 → 2026-08-30
tmin12Zbilinearall28 1 QC2.10 [1.73, 2.59]1.88-0.51 [-1.92, 1.11]2.51 [2.03, 3.16]25% [8%, 43%]57%79%-0.30-0.152026-08-03 → 2026-08-30
tmin12Znearest30d28 1 QC1.92 [1.55, 2.46]1.89-0.08 [-1.38, 1.32]2.48 [1.79, 3.27]25% [15%, 37%]64%79%-0.20-0.162026-08-03 → 2026-08-30
tmin12Znearest90d28 1 QC1.92 [1.54, 2.60]1.89-0.08 [-1.43, 1.67]2.48 [1.78, 3.42]25% [14%, 37%]64%79%-0.20-0.162026-08-03 → 2026-08-30
tmin12Znearest365d28 1 QC1.92 [1.53, 2.63]1.89-0.08 [-1.51, 1.73]2.48 [1.79, 3.48]25% [12%, 38%]64%79%-0.20-0.162026-08-03 → 2026-08-30
tmin12Znearestall28 1 QC1.92 [1.54, 2.53]1.89-0.08 [-1.52, 1.55]2.48 [1.78, 3.33]25% [14%, 36%]64%79%-0.20-0.162026-08-03 → 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 2, 00Z bilinear tmax+10+50-5-102026-08-03: +1.71 °F2026-08-04: -0.05 °F2026-08-05: +0.82 °F2026-08-06: -4.17 °F2026-08-07: -3.86 °F2026-08-08: -3.17 °F2026-08-09: -1.87 °F2026-08-10: +0.38 °F2026-08-11: -0.7 °F2026-08-12: -1.51 °F2026-08-13: -4.69 °F2026-08-14: -2.73 °F2026-08-15: -0.33 °F2026-08-16: +0.93 °F2026-08-17: -0.18 °F2026-08-18: -0.64 °F2026-08-19: -0.67 °F2026-08-20: -0.85 °F2026-08-21: -0.67 °F2026-08-22: -2.59 °F2026-08-23: -2.63 °F2026-08-24: -2.58 °F2026-08-25: -0.44 °F2026-08-26: +0.34 °F2026-08-27: -6.41 °F2026-08-28: -1.9 °F2026-08-29: +1.12 °F2026-08-30: -1.58 °F2026-08-032026-08-30°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 (28 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.58
2026-08-29+1.12
2026-08-28-1.90
2026-08-27-6.41
2026-08-26+0.34
2026-08-25-0.44
2026-08-24-2.58
2026-08-23-2.63
2026-08-22-2.59
2026-08-21-0.67
2026-08-20-0.85
2026-08-19-0.67
2026-08-18-0.64
2026-08-17-0.18
2026-08-16+0.93
2026-08-15-0.33
2026-08-14-2.73
2026-08-13-4.69
2026-08-12-1.51
2026-08-11-0.70
2026-08-10+0.38
2026-08-09-1.87
2026-08-08-3.17
2026-08-07-3.86
2026-08-06-4.17
2026-08-05+0.82
2026-08-04-0.05
2026-08-03+1.71

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAT, lead day 2-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 1 day-6 to -5 °F: 0 days-5 to -4 °F: 2 days-4 to -3 °F: 2 days-3 to -2 °F: 4 days-2 to -1 °F: 4 days-1 to 0 °F: 9 days0 to 1 °F: 4 days1 to 2 °F: 2 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| 1.32 · P90 |e| 3.95 °F-100+10 °Fn = 28 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
-7.00-6.001
-6.00-5.000
-5.00-4.002
-4.00-3.002
-3.00-2.004
-2.00-1.004
-1.00+0.009
+0.00+1.004
+1.00+2.002
+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
2026-08281.77 -1.39

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-03 → 2026-08-30 28
NCEP GFS2026-08-03 → 2026-08-30 28
NCEP GFS2026-08-03 → 2026-08-30 28
NCEP GFS2026-08-03 → 2026-08-30 28

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 28 -1.33 [-1.86, -0.73] yes
Aurora (IFS init) 1 -3.06 [-3.06, -3.06] yes
FourCastNet v2 (IFS init) 1 -0.09 [-0.09, -0.09] yes
GraphCast (IFS init) 26 -3.90 [-5.11, -2.24] yes
ECMWF IFS HRES 22 -1.37 [-2.26, -0.09] yes
Pangu-Weather (IFS init) 1 -2.63 [-2.63, -2.63] yes
Persistence (baseline) 28 +0.30 [-0.36, 1.00] no

Cite this page

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

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

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