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

Phoenix Sky Harbor · ECMWF AIFS Single · lead day 4

KPHX · 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, 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
tmax00Zbilinear30d26 1 QC3.81 [2.50, 5.60]2.55-3.61 [-5.51, -2.17]4.99 [3.11, 7.08]15% [4%, 29%]31%58%+0.31+0.542026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC3.81 [2.38, 6.24]2.55-3.61 [-6.20, -2.13]4.99 [2.89, 7.80]15% [0%, 31%]31%58%+0.31+0.542026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC3.81 [2.23, 6.58]2.55-3.61 [-6.58, -1.92]4.99 [2.71, 7.90]15% [0%, 31%]31%58%+0.31+0.542026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC3.81 [2.32, 6.44]2.55-3.61 [-6.44, -2.03]4.99 [2.84, 8.01]15% [0%, 33%]31%58%+0.31+0.542026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC3.78 [2.45, 5.60]2.55-3.58 [-5.50, -2.15]4.98 [3.08, 7.10]15% [4%, 29%]27%58%+0.32+0.552026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC3.78 [2.35, 6.25]2.55-3.58 [-6.20, -2.10]4.98 [2.85, 7.86]15% [0%, 31%]27%58%+0.32+0.552026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC3.78 [2.18, 6.61]2.55-3.58 [-6.61, -1.90]4.98 [2.65, 7.94]15% [0%, 31%]27%58%+0.32+0.552026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC3.78 [2.27, 6.44]2.55-3.58 [-6.44, -2.00]4.98 [2.79, 8.07]15% [0%, 33%]27%58%+0.32+0.552026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC4.04 [3.01, 5.29]1.93-3.94 [-5.29, -2.79]4.79 [3.44, 6.25]0% [0%, 0%]19%38%+0.27+0.662026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC4.04 [2.85, 5.78]1.93-3.94 [-5.78, -2.65]4.79 [3.05, 6.79]0% [0%, 0%]19%38%+0.27+0.662026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC4.04 [2.69, 6.00]1.93-3.94 [-6.00, -2.51]4.79 [2.89, 6.89]0% [0%, 0%]19%38%+0.27+0.662026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC4.04 [2.85, 5.93]1.93-3.94 [-5.93, -2.67]4.79 [3.02, 6.86]0% [0%, 0%]19%38%+0.27+0.662026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC3.99 [2.96, 5.26]1.93-3.90 [-5.26, -2.77]4.75 [3.40, 6.24]0% [0%, 0%]19%38%+0.28+0.652026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC3.99 [2.81, 5.76]1.93-3.90 [-5.75, -2.64]4.75 [3.02, 6.79]0% [0%, 0%]19%38%+0.28+0.652026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC3.99 [2.65, 5.96]1.93-3.90 [-5.96, -2.50]4.75 [2.85, 6.89]0% [0%, 0%]19%38%+0.28+0.652026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC3.99 [2.81, 5.90]1.93-3.90 [-5.90, -2.65]4.75 [2.98, 6.85]0% [0%, 0%]19%38%+0.28+0.652026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC4.00 [2.89, 5.23]3.26-2.18 [-4.16, -0.61]4.78 [3.63, 5.83]12% [0%, 23%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC4.00 [2.78, 5.41]3.26-2.18 [-4.55, -0.38]4.78 [3.51, 5.96]12% [0%, 24%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC4.00 [2.69, 5.47]3.26-2.18 [-4.71, -0.35]4.78 [3.41, 6.01]12% [0%, 24%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC4.00 [2.72, 5.41]3.26-2.18 [-4.77, -0.22]4.78 [3.44, 6.00]12% [0%, 24%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC4.04 [2.91, 5.28]3.27-2.22 [-4.19, -0.64]4.81 [3.65, 5.87]12% [0%, 23%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC4.04 [2.80, 5.46]3.27-2.22 [-4.56, -0.42]4.81 [3.47, 5.98]12% [0%, 24%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC4.04 [2.72, 5.51]3.27-2.22 [-4.77, -0.43]4.81 [3.44, 6.04]12% [0%, 24%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC4.04 [2.75, 5.46]3.27-2.22 [-4.82, -0.26]4.81 [3.47, 6.02]12% [0%, 24%]27%46%+0.29+0.422026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC3.87 [2.74, 5.29]3.32-2.04 [-3.72, -0.42]4.82 [3.56, 6.07]15% [4%, 26%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC3.87 [2.64, 5.39]3.32-2.04 [-3.89, -0.31]4.82 [3.33, 6.24]15% [0%, 26%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC3.87 [2.57, 5.48]3.32-2.04 [-4.03, -0.19]4.82 [3.30, 6.26]15% [0%, 26%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC3.87 [2.62, 5.35]3.32-2.04 [-4.07, -0.12]4.82 [3.30, 6.15]15% [0%, 29%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC3.90 [2.75, 5.33]3.35-2.06 [-3.74, -0.45]4.84 [3.57, 6.12]19% [7%, 30%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC3.90 [2.64, 5.44]3.35-2.06 [-3.90, -0.34]4.84 [3.31, 6.27]19% [3%, 31%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC3.90 [2.59, 5.52]3.35-2.06 [-4.06, -0.21]4.84 [3.28, 6.28]19% [0%, 31%]35%46%+0.31+0.412026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC3.90 [2.63, 5.39]3.35-2.06 [-4.12, -0.13]4.84 [3.30, 6.19]19% [0%, 31%]35%46%+0.31+0.412026-08-05 → 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 KPHX, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: -0.79 °F2026-08-06: -4.26 °F2026-08-07: -2.89 °F2026-08-08: -2.75 °F2026-08-09: -2.27 °F2026-08-10: -2.77 °F2026-08-11: -1.98 °F2026-08-12: -7.89 °F2026-08-13: -0.39 °F2026-08-14: +0.49 °F2026-08-15: -3.98 °F2026-08-16: -2.28 °F2026-08-17: -1.23 °F2026-08-18: -1.98 °F2026-08-19: -0.4 °F2026-08-20: +2.17 °F2026-08-21: -2.57 °F2026-08-22: -6.41 °F2026-08-23: -7.89 °F2026-08-24: -3.77 °F2026-08-25: -5.25 °F2026-08-26: -5.51 °F2026-08-27: -1.36 °F2026-08-28: -4.6 °F2026-08-29: -8.02 °F2026-08-30: -15.22 °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
2026-08-30-15.22
2026-08-29-8.02
2026-08-28-4.60
2026-08-27-1.36
2026-08-26-5.51
2026-08-25-5.25
2026-08-24-3.77
2026-08-23-7.89
2026-08-22-6.41
2026-08-21-2.57
2026-08-20+2.17
2026-08-19-0.40
2026-08-18-1.98
2026-08-17-1.23
2026-08-16-2.28
2026-08-15-3.98
2026-08-14+0.49
2026-08-13-0.39
2026-08-12-7.89
2026-08-11-1.98
2026-08-10-2.77
2026-08-09-2.27
2026-08-08-2.75
2026-08-07-2.89
2026-08-06-4.26
2026-08-05-0.79

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHX, lead day 4-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 1 day-14 to -12 °F: 0 days-12 to -10 °F: 0 days-10 to -8 °F: 1 day-8 to -6 °F: 3 days-6 to -4 °F: 4 days-4 to -2 °F: 8 days-2 to 0 °F: 7 days0 to 2 °F: 1 day2 to 4 °F: 1 day4 to 6 °F: 0 days6 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| 2.76 · P90 |e| 7.89 °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
-16.00-14.001
-14.00-12.000
-12.00-10.000
-10.00-8.001
-8.00-6.003
-6.00-4.004
-4.00-2.008
-2.00+0.007
+0.00+2.001
+2.00+4.001
+4.00+6.000
+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
2026-08263.81 -3.61

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 +0.32 [-0.89, 1.72] no
GraphCast (IFS init) 25 -0.65 [-1.68, 0.36] no
ECMWF IFS HRES 20 +1.17 [-0.84, 3.77] no
Persistence (baseline) 26 -1.73 [-5.20, 2.76] no

Cite this page

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

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