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 3

KSAT · gfs · lead 3

Target day = initialization date + 3 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
tmax00Zbilinear30d27 1 QC1.61 [1.07, 2.19]1.38-1.28 [-1.82, -0.68]2.11 [1.49, 2.62]41% [18%, 63%]70%78%+0.01+0.162026-08-04 → 2026-08-30
tmax00Zbilinear90d27 1 QC1.61 [1.01, 2.26]1.38-1.28 [-1.80, -0.62]2.11 [1.36, 2.68]41% [14%, 64%]70%78%+0.01+0.162026-08-04 → 2026-08-30
tmax00Zbilinear365d27 1 QC1.61 [0.99, 2.27]1.38-1.28 [-1.85, -0.56]2.11 [1.30, 2.67]41% [12%, 67%]70%78%+0.01+0.162026-08-04 → 2026-08-30
tmax00Zbilinearall27 1 QC1.61 [1.06, 2.30]1.38-1.28 [-1.83, -0.61]2.11 [1.41, 2.68]41% [10%, 65%]70%78%+0.01+0.162026-08-04 → 2026-08-30
tmax00Znearest30d27 1 QC1.53 [0.95, 2.14]1.45-1.03 [-1.60, -0.37]2.02 [1.38, 2.54]41% [18%, 64%]74%81%+0.06+0.112026-08-04 → 2026-08-30
tmax00Znearest90d27 1 QC1.53 [0.90, 2.24]1.45-1.03 [-1.58, -0.33]2.02 [1.26, 2.60]41% [14%, 67%]74%81%+0.06+0.112026-08-04 → 2026-08-30
tmax00Znearest365d27 1 QC1.53 [0.87, 2.24]1.45-1.03 [-1.61, -0.27]2.02 [1.22, 2.60]41% [14%, 72%]74%81%+0.06+0.112026-08-04 → 2026-08-30
tmax00Znearestall27 1 QC1.53 [0.93, 2.29]1.45-1.03 [-1.60, -0.28]2.02 [1.31, 2.61]41% [13%, 71%]74%81%+0.06+0.112026-08-04 → 2026-08-30
tmax12Zbilinear30d27 1 QC1.66 [1.13, 2.27]1.53-1.30 [-1.93, -0.76]2.51 [1.47, 3.53]48% [34%, 67%]74%81%-0.02+0.062026-08-04 → 2026-08-30
tmax12Zbilinear90d27 1 QC1.66 [1.06, 2.39]1.53-1.30 [-1.97, -0.64]2.51 [1.36, 3.64]48% [33%, 67%]74%81%-0.02+0.062026-08-04 → 2026-08-30
tmax12Zbilinear365d27 1 QC1.66 [0.99, 2.40]1.53-1.30 [-1.95, -0.60]2.51 [1.25, 3.76]48% [32%, 69%]74%81%-0.02+0.062026-08-04 → 2026-08-30
tmax12Zbilinearall27 1 QC1.66 [1.07, 2.37]1.53-1.30 [-1.95, -0.69]2.51 [1.39, 3.62]48% [33%, 67%]74%81%-0.02+0.062026-08-04 → 2026-08-30
tmax12Znearest30d27 1 QC1.64 [1.07, 2.31]1.57-1.14 [-1.80, -0.53]2.49 [1.39, 3.62]44% [35%, 57%]74%89%-0.01+0.042026-08-04 → 2026-08-30
tmax12Znearest90d27 1 QC1.64 [1.01, 2.43]1.57-1.14 [-1.86, -0.44]2.49 [1.29, 3.74]44% [33%, 58%]74%89%-0.01+0.042026-08-04 → 2026-08-30
tmax12Znearest365d27 1 QC1.64 [0.92, 2.48]1.57-1.14 [-1.87, -0.39]2.49 [1.17, 3.87]44% [32%, 58%]74%89%-0.01+0.042026-08-04 → 2026-08-30
tmax12Znearestall27 1 QC1.64 [1.02, 2.42]1.57-1.14 [-1.88, -0.49]2.49 [1.32, 3.69]44% [33%, 57%]74%89%-0.01+0.042026-08-04 → 2026-08-30
tmin00Zbilinear30d27 1 QC1.96 [1.48, 2.37]1.75-0.63 [-1.82, 0.63]2.36 [1.75, 2.94]26% [11%, 42%]48%85%-0.66-0.452026-08-04 → 2026-08-30
tmin00Zbilinear90d27 1 QC1.96 [1.36, 2.43]1.75-0.63 [-1.86, 1.03]2.36 [1.65, 3.04]26% [9%, 45%]48%85%-0.66-0.452026-08-04 → 2026-08-30
tmin00Zbilinear365d27 1 QC1.96 [1.34, 2.42]1.75-0.63 [-1.97, 1.16]2.36 [1.65, 3.06]26% [7%, 46%]48%85%-0.66-0.452026-08-04 → 2026-08-30
tmin00Zbilinearall27 1 QC1.96 [1.33, 2.39]1.75-0.63 [-1.95, 0.92]2.36 [1.63, 2.99]26% [8%, 46%]48%85%-0.66-0.452026-08-04 → 2026-08-30
tmin00Znearest30d27 1 QC1.83 [1.24, 2.34]1.77-0.18 [-1.38, 1.09]2.32 [1.50, 3.11]37% [13%, 67%]70%85%-0.55-0.472026-08-04 → 2026-08-30
tmin00Znearest90d27 1 QC1.83 [1.16, 2.43]1.77-0.18 [-1.43, 1.49]2.32 [1.44, 3.23]37% [14%, 73%]70%85%-0.55-0.472026-08-04 → 2026-08-30
tmin00Znearest365d27 1 QC1.83 [1.09, 2.47]1.77-0.18 [-1.57, 1.65]2.32 [1.37, 3.26]37% [12%, 72%]70%85%-0.55-0.472026-08-04 → 2026-08-30
tmin00Znearestall27 1 QC1.83 [1.11, 2.37]1.77-0.18 [-1.53, 1.37]2.32 [1.37, 3.16]37% [13%, 80%]70%85%-0.55-0.472026-08-04 → 2026-08-30
tmin12Zbilinear30d27 1 QC2.15 [1.75, 2.63]1.82-0.76 [-1.99, 0.54]2.45 [1.92, 3.10]11% [3%, 22%]48%89%-0.82-0.502026-08-04 → 2026-08-30
tmin12Zbilinear90d27 1 QC2.15 [1.63, 2.74]1.82-0.76 [-2.03, 0.82]2.45 [1.80, 3.24]11% [0%, 25%]48%89%-0.82-0.502026-08-04 → 2026-08-30
tmin12Zbilinear365d27 1 QC2.15 [1.61, 2.84]1.82-0.76 [-2.05, 0.93]2.45 [1.82, 3.32]11% [0%, 25%]48%89%-0.82-0.502026-08-04 → 2026-08-30
tmin12Zbilinearall27 1 QC2.15 [1.62, 2.74]1.82-0.76 [-2.05, 0.73]2.45 [1.84, 3.18]11% [0%, 29%]48%89%-0.82-0.502026-08-04 → 2026-08-30
tmin12Znearest30d27 1 QC1.96 [1.46, 2.55]1.83-0.33 [-1.58, 1.01]2.37 [1.60, 3.17]19% [4%, 37%]70%85%-0.66-0.512026-08-04 → 2026-08-30
tmin12Znearest90d27 1 QC1.96 [1.38, 2.68]1.83-0.33 [-1.62, 1.30]2.37 [1.52, 3.36]19% [4%, 41%]70%85%-0.66-0.512026-08-04 → 2026-08-30
tmin12Znearest365d27 1 QC1.96 [1.33, 2.76]1.83-0.33 [-1.65, 1.40]2.37 [1.49, 3.46]19% [0%, 43%]70%85%-0.66-0.512026-08-04 → 2026-08-30
tmin12Znearestall27 1 QC1.96 [1.38, 2.63]1.83-0.33 [-1.63, 1.21]2.37 [1.54, 3.28]19% [0%, 43%]70%85%-0.66-0.512026-08-04 → 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 3, 00Z bilinear tmax+5+2.50-2.5-52026-08-04: +1.55 °F2026-08-05: +1.02 °F2026-08-06: -3.12 °F2026-08-07: -3.51 °F2026-08-08: -3.23 °F2026-08-09: -4.35 °F2026-08-10: +0.55 °F2026-08-11: +0.07 °F2026-08-12: -1.65 °F2026-08-13: -4.54 °F2026-08-14: -0.78 °F2026-08-15: -0.2 °F2026-08-16: +0.88 °F2026-08-17: -0.29 °F2026-08-18: -0.06 °F2026-08-19: -1.35 °F2026-08-20: -0.53 °F2026-08-21: -1.37 °F2026-08-22: -1.83 °F2026-08-23: -2.06 °F2026-08-24: -2.65 °F2026-08-25: -1.07 °F2026-08-26: -0.12 °F2026-08-27: -4.17 °F2026-08-28: -0.78 °F2026-08-29: +0.34 °F2026-08-30: -1.46 °F2026-08-042026-08-30°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 (27 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.46
2026-08-29+0.34
2026-08-28-0.78
2026-08-27-4.17
2026-08-26-0.12
2026-08-25-1.07
2026-08-24-2.65
2026-08-23-2.06
2026-08-22-1.83
2026-08-21-1.37
2026-08-20-0.53
2026-08-19-1.35
2026-08-18-0.06
2026-08-17-0.29
2026-08-16+0.88
2026-08-15-0.20
2026-08-14-0.78
2026-08-13-4.54
2026-08-12-1.65
2026-08-11+0.07
2026-08-10+0.55
2026-08-09-4.35
2026-08-08-3.23
2026-08-07-3.51
2026-08-06-3.12
2026-08-05+1.02
2026-08-04+1.55

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAT, lead day 3-5 to -4.5 °F: 1 day-4.5 to -4 °F: 2 days-4 to -3.5 °F: 1 day-3.5 to -3 °F: 2 days-3 to -2.5 °F: 1 day-2.5 to -2 °F: 1 day-2 to -1.5 °F: 2 days-1.5 to -1 °F: 4 days-1 to -0.5 °F: 3 days-0.5 to 0 °F: 4 days0 to 0.5 °F: 2 days0.5 to 1 °F: 2 days1 to 1.5 °F: 1 day1.5 to 2 °F: 1 day2 to 2.5 °F: 0 days2.5 to 3 °F: 0 days3 to 3.5 °F: 0 days3.5 to 4 °F: 0 days4 to 4.5 °F: 0 days4.5 to 5 °F: 0 daysdashed: P50 |e| 1.35 · P90 |e| 3.77 °F-50+5 °Fn = 27 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
-5.00-4.501
-4.50-4.002
-4.00-3.501
-3.50-3.002
-3.00-2.501
-2.50-2.001
-2.00-1.502
-1.50-1.004
-1.00-0.503
-0.50+0.004
+0.00+0.502
+0.50+1.002
+1.00+1.501
+1.50+2.001
+2.00+2.500
+2.50+3.000
+3.00+3.500
+3.50+4.000
+4.00+4.500
+4.50+5.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08271.61 -1.28

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27

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 27 -1.42 [-2.12, -0.48] yes
GraphCast (IFS init) 25 -4.08 [-5.73, -1.69] yes
ECMWF IFS HRES 22 -1.63 [-2.10, -0.89] yes
Persistence (baseline) 27 -0.02 [-1.04, 1.07] no

Cite this page

ShortCastCheck, KSAT gfs lead 3, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAT/model/gfs/lead/3/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAT (San Antonio Intl), model gfs, lead day 3. 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/3/

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