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

New Orleans Intl · NCEP GFS · lead day 4

KMSY · 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, 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 QC4.12 [3.42, 4.83]1.77-4.12 [-4.83, -3.42]4.70 [3.80, 5.54]8% [0%, 15%]19%31%-0.65+0.302026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC4.12 [3.35, 4.93]1.77-4.12 [-4.93, -3.34]4.70 [3.65, 5.69]8% [0%, 15%]19%31%-0.65+0.302026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC4.12 [3.33, 4.89]1.77-4.12 [-4.89, -3.32]4.70 [3.56, 5.72]8% [0%, 15%]19%31%-0.65+0.302026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC4.12 [3.27, 4.80]1.77-4.12 [-4.80, -3.26]4.70 [3.56, 5.64]8% [0%, 15%]19%31%-0.65+0.302026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC4.22 [3.51, 4.95]1.80-4.22 [-4.95, -3.51]4.81 [3.88, 5.66]8% [0%, 15%]15%31%-0.69+0.282026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC4.22 [3.44, 5.06]1.80-4.22 [-5.06, -3.44]4.81 [3.71, 5.80]8% [0%, 15%]15%31%-0.69+0.282026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC4.22 [3.40, 5.00]1.80-4.22 [-5.00, -3.40]4.81 [3.69, 5.86]8% [0%, 15%]15%31%-0.69+0.282026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC4.22 [3.38, 4.91]1.80-4.22 [-4.91, -3.38]4.81 [3.67, 5.74]8% [0%, 15%]15%31%-0.69+0.282026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC4.47 [3.51, 5.86]2.22-4.16 [-5.29, -3.36]5.16 [3.89, 6.74]4% [0%, 11%]8%31%-0.79+0.122026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC4.47 [3.31, 6.30]2.22-4.16 [-5.60, -3.21]5.16 [3.68, 7.11]4% [0%, 11%]8%31%-0.79+0.122026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC4.47 [3.32, 6.49]2.22-4.16 [-5.63, -3.14]5.16 [3.71, 7.29]4% [0%, 12%]8%31%-0.79+0.122026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC4.47 [3.32, 6.27]2.22-4.16 [-5.63, -3.20]5.16 [3.67, 7.01]4% [0%, 12%]8%31%-0.79+0.122026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC4.57 [3.63, 5.94]2.24-4.27 [-5.40, -3.48]5.26 [4.01, 6.80]4% [0%, 11%]8%23%-0.83+0.112026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC4.57 [3.43, 6.38]2.24-4.27 [-5.71, -3.35]5.26 [3.80, 7.16]4% [0%, 11%]8%23%-0.83+0.112026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC4.57 [3.42, 6.55]2.24-4.27 [-5.73, -3.27]5.26 [3.82, 7.35]4% [0%, 12%]8%23%-0.83+0.112026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC4.57 [3.43, 6.35]2.24-4.27 [-5.73, -3.32]5.26 [3.80, 7.07]4% [0%, 12%]8%23%-0.83+0.112026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC2.07 [1.51, 2.70]1.77+1.29 [0.13, 2.25]2.50 [1.88, 3.07]27% [16%, 39%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC2.07 [1.48, 2.78]1.77+1.29 [0.01, 2.31]2.50 [1.83, 3.15]27% [15%, 39%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC2.07 [1.44, 2.79]1.77+1.29 [-0.08, 2.33]2.50 [1.80, 3.22]27% [14%, 43%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC2.07 [1.43, 2.80]1.77+1.29 [-0.03, 2.33]2.50 [1.76, 3.18]27% [14%, 41%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC2.09 [1.51, 2.72]1.77+1.33 [0.16, 2.28]2.51 [1.89, 3.09]27% [16%, 39%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC2.09 [1.50, 2.81]1.77+1.33 [0.05, 2.35]2.51 [1.85, 3.17]27% [15%, 39%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC2.09 [1.44, 2.82]1.77+1.33 [-0.04, 2.37]2.51 [1.81, 3.23]27% [14%, 43%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC2.09 [1.43, 2.82]1.77+1.33 [0.00, 2.36]2.51 [1.77, 3.19]27% [14%, 41%]50%73%-0.04+0.112026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC1.91 [1.18, 2.71]1.61+1.25 [0.28, 2.10]2.46 [1.58, 3.28]38% [24%, 54%]62%73%+0.05+0.192026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC1.91 [1.17, 2.91]1.61+1.25 [0.10, 2.12]2.46 [1.51, 3.39]38% [23%, 53%]62%73%+0.05+0.192026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC1.91 [1.04, 3.01]1.61+1.25 [-0.02, 2.18]2.46 [1.42, 3.57]38% [21%, 57%]62%73%+0.05+0.192026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC1.91 [1.12, 2.97]1.61+1.25 [0.04, 2.30]2.46 [1.42, 3.47]38% [21%, 55%]62%73%+0.05+0.192026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC1.93 [1.20, 2.75]1.61+1.29 [0.32, 2.14]2.48 [1.60, 3.30]38% [24%, 54%]62%73%+0.03+0.192026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC1.93 [1.20, 2.94]1.61+1.29 [0.14, 2.17]2.48 [1.54, 3.41]38% [23%, 53%]62%73%+0.03+0.192026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC1.93 [1.07, 3.04]1.61+1.29 [0.03, 2.22]2.48 [1.43, 3.58]38% [21%, 57%]62%73%+0.03+0.192026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC1.93 [1.14, 3.00]1.61+1.29 [0.09, 2.34]2.48 [1.44, 3.50]38% [21%, 55%]62%73%+0.03+0.192026-08-05 → 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 KMSY, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: -3.1 °F2026-08-06: -4.17 °F2026-08-07: -3.34 °F2026-08-08: -2.74 °F2026-08-09: -1.48 °F2026-08-10: -5.74 °F2026-08-11: -3.55 °F2026-08-12: +0.03 °F2026-08-13: -2.98 °F2026-08-14: -3.78 °F2026-08-15: -7.63 °F2026-08-16: -6.51 °F2026-08-17: -4.99 °F2026-08-18: -4.04 °F2026-08-19: -1.54 °F2026-08-20: -5.77 °F2026-08-21: -4.83 °F2026-08-22: -3.14 °F2026-08-23: -4.34 °F2026-08-24: -5.17 °F2026-08-25: -5.49 °F2026-08-26: -1.97 °F2026-08-27: -0.54 °F2026-08-28: -10.12 °F2026-08-29: -7.71 °F2026-08-30: -2.42 °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
2026-08-30-2.42
2026-08-29-7.71
2026-08-28-10.12
2026-08-27-0.54
2026-08-26-1.97
2026-08-25-5.49
2026-08-24-5.17
2026-08-23-4.34
2026-08-22-3.14
2026-08-21-4.83
2026-08-20-5.77
2026-08-19-1.54
2026-08-18-4.04
2026-08-17-4.99
2026-08-16-6.51
2026-08-15-7.63
2026-08-14-3.78
2026-08-13-2.98
2026-08-12+0.03
2026-08-11-3.55
2026-08-10-5.74
2026-08-09-1.48
2026-08-08-2.74
2026-08-07-3.34
2026-08-06-4.17
2026-08-05-3.10

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KMSY, 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: 0 days-8 to -6 °F: 3 days-6 to -4 °F: 9 days-4 to -2 °F: 8 days-2 to 0 °F: 4 days0 to 2 °F: 1 day2 to 4 °F: 0 days4 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| 3.91 · P90 |e| 7.07 °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
-10.00-8.000
-8.00-6.003
-6.00-4.009
-4.00-2.008
-2.00+0.004
+0.00+2.001
+2.00+4.000
+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
2026-08264.12 -4.12

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 -0.59 [-1.63, 0.55] no
GraphCast (IFS init) 25 -1.47 [-2.33, -0.33] yes
ECMWF IFS HRES 20 -0.89 [-2.95, 0.02] no
Persistence (baseline) 26 +1.62 [-0.04, 3.13] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KMSY (New Orleans Intl), 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/KMSY/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