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

Phoenix Sky Harbor · ECMWF AIFS Single · lead day 6

KPHX · aifs_single · 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, 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, 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 QC4.92 [3.43, 6.60]3.50-4.35 [-6.28, -2.61]5.99 [4.47, 7.41]21% [8%, 34%]33%33%+0.02+0.302026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC4.92 [3.45, 6.77]3.50-4.35 [-6.59, -2.54]5.99 [4.47, 7.55]21% [6%, 35%]33%33%+0.02+0.302026-08-07 → 2026-08-30
tmax00Zbilinear365d24 1 QC4.92 [3.25, 6.90]3.50-4.35 [-6.63, -2.30]5.99 [4.18, 7.69]21% [4%, 36%]33%33%+0.02+0.302026-08-07 → 2026-08-30
tmax00Zbilinearall24 1 QC4.92 [3.33, 7.12]3.50-4.35 [-6.74, -2.65]5.99 [4.31, 7.79]21% [0%, 36%]33%33%+0.02+0.302026-08-07 → 2026-08-30
tmax00Znearest30d24 1 QC4.90 [3.40, 6.57]3.49-4.34 [-6.25, -2.61]5.97 [4.46, 7.39]21% [8%, 34%]33%33%+0.02+0.312026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC4.90 [3.43, 6.73]3.49-4.34 [-6.55, -2.56]5.97 [4.46, 7.52]21% [6%, 35%]33%33%+0.02+0.312026-08-07 → 2026-08-30
tmax00Znearest365d24 1 QC4.90 [3.23, 6.89]3.49-4.34 [-6.60, -2.32]5.97 [4.19, 7.67]21% [4%, 36%]33%33%+0.02+0.312026-08-07 → 2026-08-30
tmax00Znearestall24 1 QC4.90 [3.30, 7.11]3.49-4.34 [-6.71, -2.66]5.97 [4.29, 7.77]21% [0%, 36%]33%33%+0.02+0.312026-08-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC4.91 [3.60, 6.44]3.19-4.42 [-6.30, -2.65]5.84 [4.46, 7.29]8% [0%, 15%]21%38%+0.02+0.372026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC4.91 [3.56, 6.77]3.19-4.42 [-6.74, -2.63]5.84 [4.37, 7.58]8% [0%, 15%]21%38%+0.02+0.372026-08-07 → 2026-08-30
tmax12Zbilinear365d24 1 QC4.91 [3.36, 6.70]3.19-4.42 [-6.65, -2.44]5.84 [4.15, 7.48]8% [0%, 15%]21%38%+0.02+0.372026-08-07 → 2026-08-30
tmax12Zbilinearall24 1 QC4.91 [3.52, 7.05]3.19-4.42 [-7.04, -2.70]5.84 [4.39, 7.84]8% [0%, 15%]21%38%+0.02+0.372026-08-07 → 2026-08-30
tmax12Znearest30d24 1 QC4.87 [3.58, 6.42]3.18-4.39 [-6.25, -2.64]5.80 [4.43, 7.26]8% [0%, 15%]25%38%+0.03+0.372026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC4.87 [3.53, 6.73]3.18-4.39 [-6.68, -2.62]5.80 [4.33, 7.55]8% [0%, 15%]25%38%+0.03+0.372026-08-07 → 2026-08-30
tmax12Znearest365d24 1 QC4.87 [3.33, 6.66]3.18-4.39 [-6.61, -2.44]5.80 [4.12, 7.45]8% [0%, 15%]25%38%+0.03+0.372026-08-07 → 2026-08-30
tmax12Znearestall24 1 QC4.87 [3.49, 6.99]3.18-4.39 [-6.89, -2.69]5.80 [4.38, 7.79]8% [0%, 15%]25%38%+0.03+0.372026-08-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC4.29 [2.93, 5.70]3.74-2.30 [-4.53, -0.54]5.34 [4.00, 6.60]21% [8%, 30%]33%42%+0.25+0.352026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC4.29 [2.79, 5.71]3.74-2.30 [-4.84, -0.42]5.34 [3.85, 6.65]21% [0%, 30%]33%42%+0.25+0.352026-08-07 → 2026-08-30
tmin00Zbilinear365d24 1 QC4.29 [2.70, 5.89]3.74-2.30 [-4.96, -0.24]5.34 [3.78, 6.69]21% [0%, 32%]33%42%+0.25+0.352026-08-07 → 2026-08-30
tmin00Zbilinearall24 1 QC4.29 [2.80, 5.70]3.74-2.30 [-5.00, -0.22]5.34 [3.84, 6.51]21% [0%, 30%]33%42%+0.25+0.352026-08-07 → 2026-08-30
tmin00Znearest30d24 1 QC4.33 [2.95, 5.77]3.78-2.35 [-4.61, -0.61]5.38 [4.03, 6.64]17% [4%, 29%]33%42%+0.24+0.342026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC4.33 [2.79, 5.76]3.78-2.35 [-4.90, -0.47]5.38 [3.86, 6.68]17% [0%, 29%]33%42%+0.24+0.342026-08-07 → 2026-08-30
tmin00Znearest365d24 1 QC4.33 [2.69, 5.93]3.78-2.35 [-5.00, -0.29]5.38 [3.80, 6.72]17% [0%, 31%]33%42%+0.24+0.342026-08-07 → 2026-08-30
tmin00Znearestall24 1 QC4.33 [2.81, 5.75]3.78-2.35 [-5.06, -0.28]5.38 [3.86, 6.56]17% [0%, 29%]33%42%+0.24+0.342026-08-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC4.57 [3.34, 5.96]3.54-2.52 [-4.76, -0.80]5.44 [4.28, 6.64]12% [0%, 31%]17%50%+0.20+0.382026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC4.57 [3.19, 6.04]3.54-2.52 [-5.22, -0.63]5.44 [4.19, 6.69]12% [0%, 33%]17%50%+0.20+0.382026-08-07 → 2026-08-30
tmin12Zbilinear365d24 1 QC4.57 [3.10, 6.09]3.54-2.52 [-5.23, -0.43]5.44 [4.07, 6.74]12% [0%, 35%]17%50%+0.20+0.382026-08-07 → 2026-08-30
tmin12Zbilinearall24 1 QC4.57 [3.13, 6.00]3.54-2.52 [-5.45, -0.43]5.44 [4.13, 6.60]12% [0%, 33%]17%50%+0.20+0.382026-08-07 → 2026-08-30
tmin12Znearest30d24 1 QC4.62 [3.36, 6.02]3.59-2.57 [-4.84, -0.85]5.50 [4.31, 6.69]12% [0%, 31%]17%50%+0.19+0.372026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC4.62 [3.20, 6.10]3.59-2.57 [-5.26, -0.63]5.50 [4.19, 6.75]12% [0%, 33%]17%50%+0.19+0.372026-08-07 → 2026-08-30
tmin12Znearest365d24 1 QC4.62 [3.11, 6.16]3.59-2.57 [-5.25, -0.51]5.50 [4.11, 6.79]12% [0%, 35%]17%50%+0.19+0.372026-08-07 → 2026-08-30
tmin12Znearestall24 1 QC4.62 [3.15, 6.05]3.59-2.57 [-5.44, -0.51]5.50 [4.16, 6.65]12% [0%, 33%]17%50%+0.19+0.372026-08-07 → 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 ECMWF AIFS Single at KPHX, lead day 6, 00Z bilinear tmax+20+100-10-202026-08-07: -7.32 °F2026-08-08: -5.21 °F2026-08-09: -4.01 °F2026-08-10: -0.69 °F2026-08-11: -1.1 °F2026-08-12: -9.06 °F2026-08-13: -6.83 °F2026-08-14: +0.54 °F2026-08-15: -0.92 °F2026-08-16: -1.17 °F2026-08-17: -3.71 °F2026-08-18: -4.79 °F2026-08-19: +0.56 °F2026-08-20: +5.4 °F2026-08-21: -3.72 °F2026-08-22: -8.71 °F2026-08-23: -9.58 °F2026-08-24: -8.13 °F2026-08-25: -5.73 °F2026-08-26: -8.55 °F2026-08-27: -1.73 °F2026-08-28: +0.34 °F2026-08-29: -10.42 °F2026-08-30: -9.93 °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
2026-08-30-9.93
2026-08-29-10.42
2026-08-28+0.34
2026-08-27-1.73
2026-08-26-8.55
2026-08-25-5.73
2026-08-24-8.13
2026-08-23-9.58
2026-08-22-8.71
2026-08-21-3.72
2026-08-20+5.40
2026-08-19+0.56
2026-08-18-4.79
2026-08-17-3.71
2026-08-16-1.17
2026-08-15-0.92
2026-08-14+0.54
2026-08-13-6.83
2026-08-12-9.06
2026-08-11-1.10
2026-08-10-0.69
2026-08-09-4.01
2026-08-08-5.21
2026-08-07-7.32

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHX, lead day 6-20 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: 6 days-8 to -6 °F: 2 days-6 to -4 °F: 4 days-4 to -2 °F: 2 days-2 to 0 °F: 5 days0 to 2 °F: 3 days2 to 4 °F: 0 days4 to 6 °F: 1 day6 to 8 °F: 0 days8 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 · P90 |e| 9.42 °F-200+20 °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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.000
-12.00-10.001
-10.00-8.006
-8.00-6.002
-6.00-4.004
-4.00-2.002
-2.00+0.005
+0.00+2.003
+2.00+4.000
+4.00+6.001
+6.00+8.000
+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
2026-08244.92 -4.35

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
NCEP GFS 24 +0.54 [-1.36, 2.20] no
GraphCast (IFS init) 24 -1.07 [-2.23, 0.20] no
ECMWF IFS HRES 19 +2.10 [1.06, 3.24] yes
Persistence (baseline) 24 -0.08 [-2.83, 3.34] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHX (Phoenix Sky Harbor), model aifs_single, 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/KPHX/model/aifs_single/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