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

Las Vegas Harry Reid · ECMWF AIFS Single · lead day 4

KLAS · aifs_single · 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, aifs-single-gpid5, 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 QC5.79 [5.09, 6.40]2.19-5.28 [-6.35, -3.97]6.20 [5.48, 6.71]0% [0%, 0%]4%12%+0.01+0.622026-08-05 → 2026-08-30
tmax00Zbilinear90d26 2 QC5.79 [4.98, 6.39]2.19-5.28 [-6.37, -3.87]6.20 [5.34, 6.70]0% [0%, 0%]4%12%+0.01+0.622026-08-05 → 2026-08-30
tmax00Zbilinear365d26 2 QC5.79 [5.01, 6.44]2.19-5.28 [-6.44, -3.84]6.20 [5.30, 6.75]0% [0%, 0%]4%12%+0.01+0.622026-08-05 → 2026-08-30
tmax00Zbilinearall26 2 QC5.79 [4.87, 6.53]2.19-5.28 [-6.53, -3.70]6.20 [5.21, 6.82]0% [0%, 0%]4%12%+0.01+0.622026-08-05 → 2026-08-30
tmax00Znearest30d26 2 QC6.71 [6.02, 7.34]2.13-6.27 [-7.33, -4.94]7.05 [6.37, 7.57]0% [0%, 0%]0%4%-0.15+0.632026-08-05 → 2026-08-30
tmax00Znearest90d26 2 QC6.71 [5.86, 7.36]2.13-6.27 [-7.35, -4.85]7.05 [6.26, 7.57]0% [0%, 0%]0%4%-0.15+0.632026-08-05 → 2026-08-30
tmax00Znearest365d26 2 QC6.71 [5.94, 7.40]2.13-6.27 [-7.40, -4.75]7.05 [6.21, 7.61]0% [0%, 0%]0%4%-0.15+0.632026-08-05 → 2026-08-30
tmax00Znearestall26 2 QC6.71 [5.83, 7.45]2.13-6.27 [-7.45, -4.64]7.05 [6.14, 7.67]0% [0%, 0%]0%4%-0.15+0.632026-08-05 → 2026-08-30
tmax12Zbilinear30d26 2 QC5.18 [4.60, 5.66]1.84-5.02 [-5.62, -4.25]5.57 [4.95, 6.02]0% [0%, 0%]4%19%+0.11+0.682026-08-05 → 2026-08-30
tmax12Zbilinear90d26 2 QC5.18 [4.52, 5.66]1.84-5.02 [-5.64, -4.20]5.57 [4.85, 6.07]0% [0%, 0%]4%19%+0.11+0.682026-08-05 → 2026-08-30
tmax12Zbilinear365d26 2 QC5.18 [4.48, 5.70]1.84-5.02 [-5.70, -4.11]5.57 [4.82, 6.08]0% [0%, 0%]4%19%+0.11+0.682026-08-05 → 2026-08-30
tmax12Zbilinearall26 2 QC5.18 [4.40, 5.75]1.84-5.02 [-5.74, -4.11]5.57 [4.79, 6.12]0% [0%, 0%]4%19%+0.11+0.682026-08-05 → 2026-08-30
tmax12Znearest30d26 2 QC6.09 [5.40, 6.64]1.82-6.02 [-6.64, -5.22]6.47 [5.87, 6.96]4% [0%, 11%]4%12%-0.04+0.692026-08-05 → 2026-08-30
tmax12Znearest90d26 2 QC6.09 [5.37, 6.68]1.82-6.02 [-6.68, -5.19]6.47 [5.78, 6.99]4% [0%, 11%]4%12%-0.04+0.692026-08-05 → 2026-08-30
tmax12Znearest365d26 2 QC6.09 [5.28, 6.69]1.82-6.02 [-6.69, -5.11]6.47 [5.70, 6.99]4% [0%, 11%]4%12%-0.04+0.692026-08-05 → 2026-08-30
tmax12Znearestall26 2 QC6.09 [5.29, 6.72]1.82-6.02 [-6.72, -5.14]6.47 [5.73, 7.02]4% [0%, 11%]4%12%-0.04+0.692026-08-05 → 2026-08-30
tmin00Zbilinear30d26 2 QC5.21 [3.84, 6.42]2.30-4.70 [-6.42, -2.45]5.63 [4.40, 6.59]4% [0%, 11%]12%19%+0.07+0.592026-08-05 → 2026-08-30
tmin00Zbilinear90d26 2 QC5.21 [3.82, 6.53]2.30-4.70 [-6.53, -2.46]5.63 [4.39, 6.71]4% [0%, 11%]12%19%+0.07+0.592026-08-05 → 2026-08-30
tmin00Zbilinear365d26 2 QC5.21 [3.62, 6.56]2.30-4.70 [-6.56, -2.12]5.63 [4.20, 6.74]4% [0%, 12%]12%19%+0.07+0.592026-08-05 → 2026-08-30
tmin00Zbilinearall26 2 QC5.21 [3.72, 6.58]2.30-4.70 [-6.58, -2.31]5.63 [4.27, 6.77]4% [0%, 12%]12%19%+0.07+0.592026-08-05 → 2026-08-30
tmin00Znearest30d26 2 QC5.86 [4.22, 7.21]2.30-5.53 [-7.21, -3.30]6.35 [5.01, 7.35]4% [0%, 11%]15%19%-0.04+0.592026-08-05 → 2026-08-30
tmin00Znearest90d26 2 QC5.86 [4.25, 7.29]2.30-5.53 [-7.29, -3.32]6.35 [5.01, 7.45]4% [0%, 11%]15%19%-0.04+0.592026-08-05 → 2026-08-30
tmin00Znearest365d26 2 QC5.86 [3.99, 7.34]2.30-5.53 [-7.34, -3.01]6.35 [4.72, 7.51]4% [0%, 12%]15%19%-0.04+0.592026-08-05 → 2026-08-30
tmin00Znearestall26 2 QC5.86 [4.11, 7.33]2.30-5.53 [-7.33, -3.15]6.35 [4.87, 7.50]4% [0%, 12%]15%19%-0.04+0.592026-08-05 → 2026-08-30
tmin12Zbilinear30d26 2 QC4.82 [3.33, 6.04]2.05-4.66 [-6.04, -2.89]5.39 [4.18, 6.30]15% [0%, 40%]15%23%+0.14+0.632026-08-05 → 2026-08-30
tmin12Zbilinear90d26 2 QC4.82 [3.30, 6.15]2.05-4.66 [-6.15, -2.87]5.39 [4.17, 6.41]15% [0%, 40%]15%23%+0.14+0.632026-08-05 → 2026-08-30
tmin12Zbilinear365d26 2 QC4.82 [3.06, 6.15]2.05-4.66 [-6.15, -2.60]5.39 [3.94, 6.43]15% [0%, 43%]15%23%+0.14+0.632026-08-05 → 2026-08-30
tmin12Zbilinearall26 2 QC4.82 [3.19, 6.18]2.05-4.66 [-6.18, -2.75]5.39 [4.03, 6.42]15% [0%, 40%]15%23%+0.14+0.632026-08-05 → 2026-08-30
tmin12Znearest30d26 2 QC5.52 [3.72, 6.91]2.06-5.51 [-6.91, -3.68]6.15 [4.82, 7.12]12% [0%, 31%]15%19%+0.02+0.632026-08-05 → 2026-08-30
tmin12Znearest90d26 2 QC5.52 [3.81, 6.99]2.06-5.51 [-6.99, -3.77]6.15 [4.84, 7.20]12% [0%, 32%]15%19%+0.02+0.632026-08-05 → 2026-08-30
tmin12Znearest365d26 2 QC5.52 [3.53, 7.00]2.06-5.51 [-7.00, -3.50]6.15 [4.63, 7.23]12% [0%, 32%]15%19%+0.02+0.632026-08-05 → 2026-08-30
tmin12Znearestall26 2 QC5.52 [3.68, 7.01]2.06-5.51 [-7.01, -3.63]6.15 [4.69, 7.25]12% [0%, 33%]15%19%+0.02+0.632026-08-05 → 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 ECMWF AIFS Single at KLAS, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: -6.03 °F2026-08-06: -3.08 °F2026-08-07: -4.05 °F2026-08-08: -7.97 °F2026-08-09: -7.68 °F2026-08-10: -2.59 °F2026-08-11: -4.52 °F2026-08-12: -11.59 °F2026-08-13: -1.59 °F2026-08-14: -5.65 °F2026-08-15: +6.67 °F2026-08-16: -4.07 °F2026-08-17: -5.17 °F2026-08-18: -4.19 °F2026-08-19: -4.25 °F2026-08-20: -9.21 °F2026-08-21: -6.99 °F2026-08-22: -8.1 °F2026-08-23: -8 °F2026-08-24: -6.02 °F2026-08-25: -5.07 °F2026-08-26: -5.49 °F2026-08-27: -7.37 °F2026-08-28: -6.56 °F2026-08-29: -5.73 °F2026-08-30: -2.88 °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
2026-08-30-2.88
2026-08-29-5.73
2026-08-28-6.56
2026-08-27-7.37
2026-08-26-5.49
2026-08-25-5.07
2026-08-24-6.02
2026-08-23-8.00
2026-08-22-8.10
2026-08-21-6.99
2026-08-20-9.21
2026-08-19-4.25
2026-08-18-4.19
2026-08-17-5.17
2026-08-16-4.07
2026-08-15+6.67
2026-08-14-5.65
2026-08-13-1.59
2026-08-12-11.59
2026-08-11-4.52
2026-08-10-2.59
2026-08-09-7.68
2026-08-08-7.97
2026-08-07-4.05
2026-08-06-3.08
2026-08-05-6.03

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KLAS, lead day 4-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 1 day-10 to -8 °F: 3 days-8 to -6 °F: 7 days-6 to -4 °F: 10 days-4 to -2 °F: 3 days-2 to 0 °F: 1 day0 to 2 °F: 0 days2 to 4 °F: 0 days4 to 6 °F: 0 days6 to 8 °F: 1 day8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 5.69 · P90 |e| 8.05 °F-200+20 °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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.000
-12.00-10.001
-10.00-8.003
-8.00-6.007
-6.00-4.0010
-4.00-2.003
-2.00+0.001
+0.00+2.000
+2.00+4.000
+4.00+6.000
+6.00+8.001
+8.00+10.000
+10.00+12.000
+12.00+14.000
+14.00+16.000
+16.00+18.000
+18.00+20.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08265.79 -5.28

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26
ECMWF AIFS Single2026-08-05 → 2026-08-30 26

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
NCEP GFS 26 +1.33 [0.43, 2.32] yes
GraphCast (IFS init) 25 -1.32 [-1.92, -0.74] yes
ECMWF IFS HRES 20 +2.62 [1.34, 3.64] yes
Persistence (baseline) 26 -0.06 [-4.00, 4.02] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), model aifs_single, 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/aifs_single/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