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

Phoenix Sky Harbor · ECMWF AIFS Single · lead day 8

KPHX · aifs_single · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 1 QC6.91 [3.83, 9.37]5.17-6.38 [-9.00, -2.90]9.35 [4.89, 11.82]5% [0%, 12%]18%36%-0.26+0.052026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC6.91 [2.88, 9.34]5.17-6.38 [-9.00, -2.04]9.35 [3.42, 11.89]5% [0%, 13%]18%36%-0.26+0.052026-08-09 → 2026-08-30
tmax00Zbilinear365d22 1 QC6.91 [3.08, 9.55]5.17-6.38 [-9.20, -2.12]9.35 [3.66, 12.15]5% [0%, 14%]18%36%-0.26+0.052026-08-09 → 2026-08-30
tmax00Zbilinearall22 1 QC6.91 [3.17, 9.70]5.17-6.38 [-9.33, -2.14]9.35 [3.81, 12.21]5% [0%, 14%]18%36%-0.26+0.052026-08-09 → 2026-08-30
tmax00Znearest30d22 1 QC6.90 [3.81, 9.35]5.14-6.38 [-8.99, -2.94]9.33 [4.88, 11.76]5% [0%, 12%]18%32%-0.26+0.062026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC6.90 [2.89, 9.32]5.14-6.38 [-8.99, -2.04]9.33 [3.41, 11.83]5% [0%, 13%]18%32%-0.26+0.062026-08-09 → 2026-08-30
tmax00Znearest365d22 1 QC6.90 [3.10, 9.52]5.14-6.38 [-9.21, -2.10]9.33 [3.66, 12.10]5% [0%, 14%]18%32%-0.26+0.062026-08-09 → 2026-08-30
tmax00Znearestall22 1 QC6.90 [3.19, 9.65]5.14-6.38 [-9.30, -2.17]9.33 [3.81, 12.14]5% [0%, 14%]18%32%-0.26+0.062026-08-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC6.21 [3.81, 8.12]4.10-5.89 [-7.86, -3.31]7.97 [4.70, 9.99]9% [0%, 22%]18%32%-0.13+0.252026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC6.21 [3.26, 8.07]4.10-5.89 [-7.92, -2.53]7.97 [3.92, 9.87]9% [0%, 25%]18%32%-0.13+0.252026-08-09 → 2026-08-30
tmax12Zbilinear365d22 1 QC6.21 [3.28, 8.29]4.10-5.89 [-8.13, -2.57]7.97 [3.98, 10.13]9% [0%, 25%]18%32%-0.13+0.252026-08-09 → 2026-08-30
tmax12Zbilinearall22 1 QC6.21 [3.15, 8.36]4.10-5.89 [-7.98, -2.53]7.97 [3.79, 10.21]9% [0%, 30%]18%32%-0.13+0.252026-08-09 → 2026-08-30
tmax12Znearest30d22 1 QC6.19 [3.81, 8.09]4.07-5.88 [-7.86, -3.32]7.94 [4.71, 9.93]9% [0%, 22%]18%32%-0.12+0.262026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC6.19 [3.23, 8.02]4.07-5.88 [-7.88, -2.58]7.94 [3.96, 9.82]9% [0%, 25%]18%32%-0.12+0.262026-08-09 → 2026-08-30
tmax12Znearest365d22 1 QC6.19 [3.28, 8.25]4.07-5.88 [-8.09, -2.61]7.94 [3.98, 10.08]9% [0%, 25%]18%32%-0.12+0.262026-08-09 → 2026-08-30
tmax12Znearestall22 1 QC6.19 [3.13, 8.30]4.07-5.88 [-7.94, -2.59]7.94 [3.79, 10.17]9% [0%, 30%]18%32%-0.12+0.262026-08-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC4.69 [3.06, 5.72]3.77-2.93 [-4.95, -0.88]5.59 [4.08, 6.44]9% [0%, 27%]27%41%+0.25+0.382026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC4.69 [2.20, 5.83]3.77-2.93 [-5.14, -0.55]5.59 [3.12, 6.50]9% [0%, 33%]27%41%+0.25+0.382026-08-09 → 2026-08-30
tmin00Zbilinear365d22 1 QC4.69 [1.94, 5.88]3.77-2.93 [-5.30, -0.74]5.59 [2.33, 6.57]9% [0%, 33%]27%41%+0.25+0.382026-08-09 → 2026-08-30
tmin00Zbilinearall22 1 QC4.69 [1.95, 5.82]3.77-2.93 [-5.17, -0.54]5.59 [2.33, 6.51]9% [0%, 33%]27%41%+0.25+0.382026-08-09 → 2026-08-30
tmin00Znearest30d22 1 QC4.73 [3.07, 5.78]3.79-2.99 [-5.02, -0.92]5.64 [4.13, 6.51]9% [0%, 27%]27%41%+0.24+0.372026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC4.73 [2.20, 5.90]3.79-2.99 [-5.24, -0.58]5.64 [3.18, 6.60]9% [0%, 33%]27%41%+0.24+0.372026-08-09 → 2026-08-30
tmin00Znearest365d22 1 QC4.73 [1.93, 5.94]3.79-2.99 [-5.40, -0.78]5.64 [2.31, 6.66]9% [0%, 33%]27%41%+0.24+0.372026-08-09 → 2026-08-30
tmin00Znearestall22 1 QC4.73 [1.93, 5.90]3.79-2.99 [-5.25, -0.53]5.64 [2.31, 6.62]9% [0%, 33%]27%41%+0.24+0.372026-08-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC4.51 [2.94, 5.70]3.69-2.88 [-4.85, -0.85]5.40 [3.88, 6.33]14% [3%, 33%]27%45%+0.28+0.392026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC4.51 [1.94, 5.78]3.69-2.88 [-4.98, -0.62]5.40 [2.31, 6.36]14% [0%, 38%]27%45%+0.28+0.392026-08-09 → 2026-08-30
tmin12Zbilinear365d22 1 QC4.51 [2.03, 5.78]3.69-2.88 [-5.18, -0.60]5.40 [2.27, 6.38]14% [0%, 40%]27%45%+0.28+0.392026-08-09 → 2026-08-30
tmin12Zbilinearall22 1 QC4.51 [1.82, 5.63]3.69-2.88 [-5.00, -0.56]5.40 [2.03, 6.34]14% [0%, 40%]27%45%+0.28+0.392026-08-09 → 2026-08-30
tmin12Znearest30d22 1 QC4.54 [2.95, 5.73]3.74-2.91 [-4.92, -0.83]5.45 [3.90, 6.38]18% [4%, 42%]27%45%+0.27+0.382026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC4.54 [1.89, 5.83]3.74-2.91 [-5.09, -0.63]5.45 [2.27, 6.46]18% [0%, 50%]27%45%+0.27+0.382026-08-09 → 2026-08-30
tmin12Znearest365d22 1 QC4.54 [1.99, 5.85]3.74-2.91 [-5.27, -0.63]5.45 [2.23, 6.48]18% [0%, 50%]27%45%+0.27+0.382026-08-09 → 2026-08-30
tmin12Znearestall22 1 QC4.54 [1.75, 5.69]3.74-2.91 [-5.11, -0.55]5.45 [1.99, 6.43]18% [0%, 50%]27%45%+0.27+0.382026-08-09 → 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 8, 00Z bilinear tmax+25+12.50-12.5-252026-08-09: -8.77 °F2026-08-10: -4.91 °F2026-08-11: -4.88 °F2026-08-12: -6.66 °F2026-08-13: -9.33 °F2026-08-14: -21.38 °F2026-08-15: -4.8 °F2026-08-16: -2.39 °F2026-08-17: -3.77 °F2026-08-18: -1.81 °F2026-08-19: +0.8 °F2026-08-20: +3.9 °F2026-08-21: -2.07 °F2026-08-22: -6.78 °F2026-08-23: -9.44 °F2026-08-24: -14.34 °F2026-08-25: -24.94 °F2026-08-26: -12.65 °F2026-08-27: -2.98 °F2026-08-28: +1.19 °F2026-08-29: -2.74 °F2026-08-30: -1.49 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.49
2026-08-29-2.74
2026-08-28+1.19
2026-08-27-2.98
2026-08-26-12.65
2026-08-25-24.94
2026-08-24-14.34
2026-08-23-9.44
2026-08-22-6.78
2026-08-21-2.07
2026-08-20+3.90
2026-08-19+0.80
2026-08-18-1.81
2026-08-17-3.77
2026-08-16-2.39
2026-08-15-4.80
2026-08-14-21.38
2026-08-13-9.33
2026-08-12-6.66
2026-08-11-4.88
2026-08-10-4.91
2026-08-09-8.77

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHX, lead day 8-25 to -22.5 °F: 1 day-22.5 to -20 °F: 1 day-20 to -17.5 °F: 0 days-17.5 to -15 °F: 0 days-15 to -12.5 °F: 2 days-12.5 to -10 °F: 0 days-10 to -7.5 °F: 3 days-7.5 to -5 °F: 2 days-5 to -2.5 °F: 6 days-2.5 to 0 °F: 4 days0 to 2.5 °F: 2 days2.5 to 5 °F: 1 day5 to 7.5 °F: 0 days7.5 to 10 °F: 0 days10 to 12.5 °F: 0 days12.5 to 15 °F: 0 days15 to 17.5 °F: 0 days17.5 to 20 °F: 0 days20 to 22.5 °F: 0 days22.5 to 25 °F: 0 daysdashed: P50 |e| 4.84 · P90 |e| 14.17 °F-250+25 °Fn = 22 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
-25.00-22.501
-22.50-20.001
-20.00-17.500
-17.50-15.000
-15.00-12.502
-12.50-10.000
-10.00-7.503
-7.50-5.002
-5.00-2.506
-2.50+0.004
+0.00+2.502
+2.50+5.001
+5.00+7.500
+7.50+10.000
+10.00+12.500
+12.50+15.000
+15.00+17.500
+17.50+20.000
+20.00+22.500
+22.50+25.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08226.91 -6.38

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22
ECMWF AIFS Single2026-08-09 → 2026-08-30 22

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 22 +2.01 [-2.56, 4.93] no
GraphCast (IFS init) 22 -2.27 [-5.80, 1.08] no
ECMWF IFS HRES 17 +1.08 [-3.88, 5.99] no
Persistence (baseline) 22 +1.41 [-2.73, 4.29] no

Cite this page

ShortCastCheck, KPHX aifs_single lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KPHX/model/aifs_single/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHX (Phoenix Sky Harbor), model aifs_single, lead day 8. 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/8/

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