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

Las Vegas Harry Reid · NCEP GFS · lead day 4

KLAS · gfs · lead 4

Target day = initialization date + 4 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, 2 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
tmax00Zbilinear30d26 2 QC4.46 [3.32, 5.27]3.26-2.80 [-4.94, -0.44]5.02 [3.94, 5.67]8% [0%, 20%]19%31%+0.24+0.442026-08-05 → 2026-08-30
tmax00Zbilinear90d26 2 QC4.46 [3.14, 5.35]3.26-2.80 [-5.15, -0.39]5.02 [3.68, 5.70]8% [0%, 20%]19%31%+0.24+0.442026-08-05 → 2026-08-30
tmax00Zbilinear365d26 2 QC4.46 [3.06, 5.43]3.26-2.80 [-5.33, -0.31]5.02 [3.67, 5.71]8% [0%, 22%]19%31%+0.24+0.442026-08-05 → 2026-08-30
tmax00Zbilinearall26 2 QC4.46 [3.08, 5.34]3.26-2.80 [-5.27, -0.30]5.02 [3.61, 5.68]8% [0%, 21%]19%31%+0.24+0.442026-08-05 → 2026-08-30
tmax00Znearest30d26 2 QC5.48 [3.78, 6.93]3.27-4.47 [-6.77, -1.92]6.07 [4.61, 7.12]8% [0%, 22%]15%23%+0.06+0.432026-08-05 → 2026-08-30
tmax00Znearest90d26 2 QC5.48 [3.27, 7.10]3.27-4.47 [-7.04, -1.90]6.07 [4.13, 7.24]8% [0%, 26%]15%23%+0.06+0.432026-08-05 → 2026-08-30
tmax00Znearest365d26 2 QC5.48 [3.27, 7.21]3.27-4.47 [-7.18, -1.79]6.07 [4.03, 7.35]8% [0%, 25%]15%23%+0.06+0.432026-08-05 → 2026-08-30
tmax00Znearestall26 2 QC5.48 [3.28, 7.13]3.27-4.47 [-7.12, -1.79]6.07 [4.07, 7.31]8% [0%, 25%]15%23%+0.06+0.432026-08-05 → 2026-08-30
tmax12Zbilinear30d26 2 QC4.28 [2.54, 5.78]3.27-2.88 [-5.62, -0.01]4.99 [3.39, 6.10]19% [0%, 41%]23%27%+0.27+0.432026-08-05 → 2026-08-30
tmax12Zbilinear90d26 2 QC4.28 [2.04, 5.91]3.27-2.88 [-5.87, 0.25]4.99 [2.85, 6.19]19% [0%, 48%]23%27%+0.27+0.432026-08-05 → 2026-08-30
tmax12Zbilinear365d26 2 QC4.28 [2.10, 6.00]3.27-2.88 [-5.99, 0.22]4.99 [2.79, 6.26]19% [0%, 45%]23%27%+0.27+0.432026-08-05 → 2026-08-30
tmax12Zbilinearall26 2 QC4.28 [2.06, 6.09]3.27-2.88 [-6.03, 0.21]4.99 [2.77, 6.32]19% [0%, 48%]23%27%+0.27+0.432026-08-05 → 2026-08-30
tmax12Znearest30d26 2 QC5.39 [3.22, 7.39]3.39-4.50 [-7.36, -1.52]6.08 [4.02, 7.56]4% [0%, 14%]27%27%+0.08+0.412026-08-05 → 2026-08-30
tmax12Znearest90d26 2 QC5.39 [2.80, 7.54]3.39-4.50 [-7.53, -1.28]6.08 [3.59, 7.69]4% [0%, 16%]27%27%+0.08+0.412026-08-05 → 2026-08-30
tmax12Znearest365d26 2 QC5.39 [2.77, 7.65]3.39-4.50 [-7.65, -1.27]6.08 [3.51, 7.79]4% [0%, 14%]27%27%+0.08+0.412026-08-05 → 2026-08-30
tmax12Znearestall26 2 QC5.39 [2.79, 7.65]3.39-4.50 [-7.65, -1.28]6.08 [3.50, 7.83]4% [0%, 15%]27%27%+0.08+0.412026-08-05 → 2026-08-30
tmin00Zbilinear30d26 2 QC3.59 [2.34, 5.00]3.54-0.20 [-3.13, 2.88]4.45 [2.86, 6.01]12% [0%, 27%]31%54%+0.36+0.372026-08-05 → 2026-08-30
tmin00Zbilinear90d26 2 QC3.59 [2.32, 5.03]3.54-0.20 [-3.59, 2.74]4.45 [2.87, 5.97]12% [0%, 29%]31%54%+0.36+0.372026-08-05 → 2026-08-30
tmin00Zbilinear365d26 2 QC3.59 [2.10, 5.09]3.54-0.20 [-3.55, 3.19]4.45 [2.61, 6.11]12% [0%, 29%]31%54%+0.36+0.372026-08-05 → 2026-08-30
tmin00Zbilinearall26 2 QC3.59 [2.13, 5.23]3.54-0.20 [-3.70, 3.00]4.45 [2.67, 6.14]12% [0%, 29%]31%54%+0.36+0.372026-08-05 → 2026-08-30
tmin00Znearest30d26 2 QC3.65 [2.50, 4.77]3.40-0.96 [-3.78, 2.00]4.41 [3.17, 5.43]15% [0%, 32%]38%42%+0.35+0.392026-08-05 → 2026-08-30
tmin00Znearest90d26 2 QC3.65 [2.37, 4.78]3.40-0.96 [-4.18, 1.88]4.41 [3.10, 5.48]15% [0%, 33%]38%42%+0.35+0.392026-08-05 → 2026-08-30
tmin00Znearest365d26 2 QC3.65 [2.21, 4.79]3.40-0.96 [-4.22, 2.25]4.41 [2.93, 5.51]15% [0%, 36%]38%42%+0.35+0.392026-08-05 → 2026-08-30
tmin00Znearestall26 2 QC3.65 [2.22, 4.86]3.40-0.96 [-4.36, 2.08]4.41 [2.98, 5.59]15% [0%, 36%]38%42%+0.35+0.392026-08-05 → 2026-08-30
tmin12Zbilinear30d26 2 QC3.87 [2.82, 5.23]3.81-0.34 [-3.30, 3.22]4.89 [3.43, 6.41]15% [4%, 30%]23%50%+0.31+0.322026-08-05 → 2026-08-30
tmin12Zbilinear90d26 2 QC3.87 [2.88, 5.32]3.81-0.34 [-3.45, 3.16]4.89 [3.51, 6.43]15% [0%, 30%]23%50%+0.31+0.322026-08-05 → 2026-08-30
tmin12Zbilinear365d26 2 QC3.87 [2.69, 5.35]3.81-0.34 [-3.54, 3.66]4.89 [3.28, 6.50]15% [0%, 31%]23%50%+0.31+0.322026-08-05 → 2026-08-30
tmin12Zbilinearall26 2 QC3.87 [2.77, 5.39]3.81-0.34 [-3.59, 3.39]4.89 [3.34, 6.48]15% [0%, 29%]23%50%+0.31+0.322026-08-05 → 2026-08-30
tmin12Znearest30d26 2 QC4.04 [3.07, 5.19]3.79-1.03 [-3.91, 2.35]4.99 [3.87, 6.10]19% [5%, 33%]31%46%+0.28+0.322026-08-05 → 2026-08-30
tmin12Znearest90d26 2 QC4.04 [3.10, 5.25]3.79-1.03 [-4.07, 2.35]4.99 [3.97, 6.13]19% [4%, 34%]31%46%+0.28+0.322026-08-05 → 2026-08-30
tmin12Znearest365d26 2 QC4.04 [2.89, 5.30]3.79-1.03 [-4.23, 2.81]4.99 [3.73, 6.24]19% [0%, 36%]31%46%+0.28+0.322026-08-05 → 2026-08-30
tmin12Znearestall26 2 QC4.04 [2.98, 5.40]3.79-1.03 [-4.23, 2.56]4.99 [3.80, 6.25]19% [0%, 35%]31%46%+0.28+0.322026-08-05 → 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 KLAS, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -4.51 °F2026-08-06: +1.97 °F2026-08-07: -1.07 °F2026-08-08: -2.44 °F2026-08-09: +1.65 °F2026-08-10: +3.43 °F2026-08-11: -8.86 °F2026-08-12: -0.94 °F2026-08-13: +5.33 °F2026-08-14: -0.4 °F2026-08-15: +9.15 °F2026-08-16: -4.36 °F2026-08-17: -5.06 °F2026-08-18: -5.27 °F2026-08-19: -5.75 °F2026-08-20: -3.62 °F2026-08-21: -8.54 °F2026-08-22: -6.05 °F2026-08-23: -5.23 °F2026-08-24: -5.01 °F2026-08-25: -2.77 °F2026-08-26: -5.29 °F2026-08-27: -5.27 °F2026-08-28: -6.96 °F2026-08-29: -4.57 °F2026-08-30: -2.35 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.35
2026-08-29-4.57
2026-08-28-6.96
2026-08-27-5.27
2026-08-26-5.29
2026-08-25-2.77
2026-08-24-5.01
2026-08-23-5.23
2026-08-22-6.05
2026-08-21-8.54
2026-08-20-3.62
2026-08-19-5.75
2026-08-18-5.27
2026-08-17-5.06
2026-08-16-4.36
2026-08-15+9.15
2026-08-14-0.40
2026-08-13+5.33
2026-08-12-0.94
2026-08-11-8.86
2026-08-10+3.43
2026-08-09+1.65
2026-08-08-2.44
2026-08-07-1.07
2026-08-06+1.97
2026-08-05-4.51

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KLAS, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 2 days-8 to -7 °F: 0 days-7 to -6 °F: 2 days-6 to -5 °F: 7 days-5 to -4 °F: 3 days-4 to -3 °F: 1 day-3 to -2 °F: 3 days-2 to -1 °F: 1 day-1 to 0 °F: 2 days0 to 1 °F: 0 days1 to 2 °F: 2 days2 to 3 °F: 0 days3 to 4 °F: 1 day4 to 5 °F: 0 days5 to 6 °F: 1 day6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 1 daydashed: P50 |e| 4.79 · P90 |e| 7.75 °F-100+10 °Fn = 26 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
-9.00-8.002
-8.00-7.000
-7.00-6.002
-6.00-5.007
-5.00-4.003
-4.00-3.001
-3.00-2.003
-2.00-1.001
-1.00+0.002
+0.00+1.000
+1.00+2.002
+2.00+3.000
+3.00+4.001
+4.00+5.000
+5.00+6.001
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.001

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08264.46 -2.80

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26

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 26 -1.33 [-2.32, -0.43] yes
GraphCast (IFS init) 25 -2.69 [-3.36, -1.89] yes
ECMWF IFS HRES 20 +1.50 [0.26, 2.58] yes
Persistence (baseline) 26 -1.39 [-4.98, 2.54] no

Cite this page

ShortCastCheck, KLAS gfs lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAS/model/gfs/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), model gfs, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KLAS/model/gfs/lead/4/

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