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

San Antonio Intl · NCEP GFS · lead day 6

KSAT · gfs · lead 6

Target day = initialization date + 6 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
tmax00Zbilinear30d24 1 QC1.63 [1.23, 2.11]1.41-1.29 [-1.95, -0.64]2.14 [1.70, 2.63]50% [37%, 62%]62%79%+0.20+0.312026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC1.63 [1.22, 2.18]1.41-1.29 [-2.13, -0.61]2.14 [1.69, 2.74]50% [38%, 64%]62%79%+0.20+0.312026-08-07 → 2026-08-30
tmax00Zbilinear365d24 1 QC1.63 [1.20, 2.22]1.41-1.29 [-2.17, -0.59]2.14 [1.63, 2.75]50% [33%, 63%]62%79%+0.20+0.312026-08-07 → 2026-08-30
tmax00Zbilinearall24 1 QC1.63 [1.19, 2.16]1.41-1.29 [-2.06, -0.55]2.14 [1.60, 2.69]50% [36%, 64%]62%79%+0.20+0.312026-08-07 → 2026-08-30
tmax00Znearest30d24 1 QC1.54 [1.16, 2.04]1.44-1.05 [-1.69, -0.45]2.05 [1.57, 2.50]50% [37%, 62%]67%83%+0.25+0.292026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC1.54 [1.15, 2.07]1.44-1.05 [-1.81, -0.42]2.05 [1.55, 2.57]50% [38%, 64%]67%83%+0.25+0.292026-08-07 → 2026-08-30
tmax00Znearest365d24 1 QC1.54 [1.11, 2.14]1.44-1.05 [-1.87, -0.42]2.05 [1.47, 2.57]50% [33%, 63%]67%83%+0.25+0.292026-08-07 → 2026-08-30
tmax00Znearestall24 1 QC1.54 [1.11, 2.09]1.44-1.05 [-1.77, -0.37]2.05 [1.44, 2.56]50% [36%, 64%]67%83%+0.25+0.292026-08-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC1.26 [0.93, 1.75]1.14-0.42 [-1.00, 0.00]1.52 [1.13, 2.00]46% [17%, 69%]83%96%+0.38+0.442026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC1.26 [0.90, 1.92]1.14-0.42 [-1.06, 0.03]1.52 [1.08, 2.13]46% [8%, 71%]83%96%+0.38+0.442026-08-07 → 2026-08-30
tmax12Zbilinear365d24 1 QC1.26 [0.84, 1.83]1.14-0.42 [-1.04, 0.01]1.52 [1.01, 2.08]46% [8%, 71%]83%96%+0.38+0.442026-08-07 → 2026-08-30
tmax12Zbilinearall24 1 QC1.26 [0.88, 1.92]1.14-0.42 [-1.11, 0.01]1.52 [1.04, 2.17]46% [0%, 71%]83%96%+0.38+0.442026-08-07 → 2026-08-30
tmax12Znearest30d24 1 QC1.09 [0.79, 1.53]1.07-0.12 [-0.60, 0.27]1.43 [1.00, 1.87]62% [44%, 78%]79%92%+0.47+0.482026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC1.09 [0.76, 1.66]1.07-0.12 [-0.66, 0.29]1.43 [0.96, 1.98]62% [38%, 80%]79%92%+0.47+0.482026-08-07 → 2026-08-30
tmax12Znearest365d24 1 QC1.09 [0.70, 1.55]1.07-0.12 [-0.65, 0.30]1.43 [0.83, 1.91]62% [38%, 82%]79%92%+0.47+0.482026-08-07 → 2026-08-30
tmax12Znearestall24 1 QC1.09 [0.72, 1.67]1.07-0.12 [-0.72, 0.31]1.43 [0.87, 1.99]62% [33%, 79%]79%92%+0.47+0.482026-08-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC2.15 [1.81, 2.55]1.75-0.87 [-1.95, 0.37]2.50 [2.04, 3.05]17% [4%, 28%]50%83%-0.39-0.112026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC2.15 [1.76, 2.63]1.75-0.87 [-1.99, 0.57]2.50 [1.96, 3.11]17% [0%, 29%]50%83%-0.39-0.112026-08-07 → 2026-08-30
tmin00Zbilinear365d24 1 QC2.15 [1.76, 2.60]1.75-0.87 [-2.00, 0.56]2.50 [1.96, 3.13]17% [0%, 29%]50%83%-0.39-0.112026-08-07 → 2026-08-30
tmin00Zbilinearall24 1 QC2.15 [1.76, 2.58]1.75-0.87 [-2.02, 0.57]2.50 [1.95, 3.08]17% [0%, 29%]50%83%-0.39-0.112026-08-07 → 2026-08-30
tmin00Znearest30d24 1 QC1.90 [1.49, 2.41]1.76-0.44 [-1.53, 0.79]2.36 [1.72, 3.04]21% [10%, 30%]62%79%-0.23-0.112026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC1.90 [1.43, 2.51]1.76-0.44 [-1.56, 1.00]2.36 [1.63, 3.18]21% [8%, 29%]62%79%-0.23-0.112026-08-07 → 2026-08-30
tmin00Znearest365d24 1 QC1.90 [1.43, 2.50]1.76-0.44 [-1.57, 1.01]2.36 [1.63, 3.14]21% [8%, 29%]62%79%-0.23-0.112026-08-07 → 2026-08-30
tmin00Znearestall24 1 QC1.90 [1.42, 2.47]1.76-0.44 [-1.58, 1.00]2.36 [1.63, 3.12]21% [8%, 29%]62%79%-0.23-0.112026-08-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC2.37 [1.98, 2.76]1.95-0.85 [-2.22, 0.64]2.71 [2.24, 3.16]17% [7%, 29%]42%67%-0.54-0.232026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC2.37 [1.93, 2.81]1.95-0.85 [-2.35, 0.82]2.71 [2.11, 3.22]17% [5%, 33%]42%67%-0.54-0.232026-08-07 → 2026-08-30
tmin12Zbilinear365d24 1 QC2.37 [1.93, 2.80]1.95-0.85 [-2.35, 0.91]2.71 [2.10, 3.22]17% [3%, 33%]42%67%-0.54-0.232026-08-07 → 2026-08-30
tmin12Zbilinearall24 1 QC2.37 [1.90, 2.77]1.95-0.85 [-2.36, 0.84]2.71 [2.10, 3.20]17% [6%, 33%]42%67%-0.54-0.232026-08-07 → 2026-08-30
tmin12Znearest30d24 1 QC2.16 [1.64, 2.73]1.96-0.42 [-1.80, 1.07]2.61 [1.97, 3.22]33% [21%, 47%]50%75%-0.40-0.242026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC2.16 [1.53, 2.80]1.96-0.42 [-1.92, 1.25]2.61 [1.80, 3.29]33% [20%, 48%]50%75%-0.40-0.242026-08-07 → 2026-08-30
tmin12Znearest365d24 1 QC2.16 [1.50, 2.79]1.96-0.42 [-1.92, 1.33]2.61 [1.75, 3.27]33% [21%, 50%]50%75%-0.40-0.242026-08-07 → 2026-08-30
tmin12Znearestall24 1 QC2.16 [1.50, 2.78]1.96-0.42 [-1.94, 1.27]2.61 [1.78, 3.26]33% [21%, 50%]50%75%-0.40-0.242026-08-07 → 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 6, 00Z bilinear tmax+5+2.50-2.5-52026-08-07: +0.41 °F2026-08-08: -2.97 °F2026-08-09: -3.1 °F2026-08-10: -0.9 °F2026-08-11: -1.7 °F2026-08-12: -0.39 °F2026-08-13: -0.03 °F2026-08-14: +2.93 °F2026-08-15: -3.97 °F2026-08-16: -0.04 °F2026-08-17: -1.19 °F2026-08-18: +0.68 °F2026-08-19: -0.02 °F2026-08-20: -2.27 °F2026-08-21: -0.83 °F2026-08-22: -3.14 °F2026-08-23: -0.25 °F2026-08-24: -0.66 °F2026-08-25: -0.65 °F2026-08-26: -2.46 °F2026-08-27: -1.71 °F2026-08-28: -4.5 °F2026-08-29: -3.98 °F2026-08-30: -0.25 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-0.25
2026-08-29-3.98
2026-08-28-4.50
2026-08-27-1.71
2026-08-26-2.46
2026-08-25-0.65
2026-08-24-0.66
2026-08-23-0.25
2026-08-22-3.14
2026-08-21-0.83
2026-08-20-2.27
2026-08-19-0.02
2026-08-18+0.68
2026-08-17-1.19
2026-08-16-0.04
2026-08-15-3.97
2026-08-14+2.93
2026-08-13-0.03
2026-08-12-0.39
2026-08-11-1.70
2026-08-10-0.90
2026-08-09-3.10
2026-08-08-2.97
2026-08-07+0.41

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAT, lead day 6-5 to -4.5 °F: 0 days-4.5 to -4 °F: 1 day-4 to -3.5 °F: 2 days-3.5 to -3 °F: 2 days-3 to -2.5 °F: 1 day-2.5 to -2 °F: 2 days-2 to -1.5 °F: 2 days-1.5 to -1 °F: 1 day-1 to -0.5 °F: 4 days-0.5 to 0 °F: 6 days0 to 0.5 °F: 1 day0.5 to 1 °F: 1 day1 to 1.5 °F: 0 days1.5 to 2 °F: 0 days2 to 2.5 °F: 0 days2.5 to 3 °F: 1 day3 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| 1.04 · P90 |e| 3.72 °F-50+5 °Fn = 24 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
-5.00-4.500
-4.50-4.001
-4.00-3.502
-3.50-3.002
-3.00-2.501
-2.50-2.002
-2.00-1.502
-1.50-1.001
-1.00-0.504
-0.50+0.006
+0.00+0.501
+0.50+1.001
+1.00+1.500
+1.50+2.000
+2.00+2.500
+2.50+3.001
+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
2026-08241.63 -1.29

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-07 → 2026-08-30 24
NCEP GFS2026-08-07 → 2026-08-30 24
NCEP GFS2026-08-07 → 2026-08-30 24
NCEP GFS2026-08-07 → 2026-08-30 24

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 24 -1.02 [-2.16, 0.39] no
GraphCast (IFS init) 24 -3.78 [-5.79, -1.17] yes
ECMWF IFS HRES 19 -1.36 [-2.44, 0.34] no
Persistence (baseline) 24 -0.42 [-1.08, 0.17] no

Cite this page

ShortCastCheck, KSAT gfs lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAT/model/gfs/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAT (San Antonio Intl), model gfs, lead day 6. 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/6/

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