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

Minneapolis-St Paul · NCEP GFS · lead day 4

KMSP · 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 QC3.81 [2.91, 4.88]3.76-0.59 [-2.61, 2.51]5.21 [3.95, 6.45]12% [0%, 25%]38%58%+0.07+0.092026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC3.81 [2.82, 4.92]3.76-0.59 [-2.74, 3.33]5.21 [3.87, 6.51]12% [0%, 29%]38%58%+0.07+0.092026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC3.81 [2.72, 5.02]3.76-0.59 [-2.85, 3.17]5.21 [3.70, 6.63]12% [0%, 29%]38%58%+0.07+0.092026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC3.81 [2.70, 5.10]3.76-0.59 [-2.75, 3.85]5.21 [3.69, 6.78]12% [0%, 31%]38%58%+0.07+0.092026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC3.92 [2.92, 5.11]3.93-0.13 [-2.34, 3.39]5.27 [4.05, 6.46]19% [4%, 33%]35%54%+0.05+0.052026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC3.92 [2.92, 5.30]3.93-0.13 [-2.43, 4.25]5.27 [4.00, 6.61]19% [0%, 34%]35%54%+0.05+0.052026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC3.92 [2.74, 5.23]3.93-0.13 [-2.54, 4.25]5.27 [3.91, 6.54]19% [0%, 35%]35%54%+0.05+0.052026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC3.92 [2.75, 5.58]3.93-0.13 [-2.40, 4.89]5.27 [3.85, 6.76]19% [0%, 36%]35%54%+0.05+0.052026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC4.56 [3.91, 5.38]4.09+1.94 [-0.51, 4.54]5.32 [4.71, 6.02]8% [0%, 17%]23%31%-0.11+0.012026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC4.56 [3.80, 5.55]4.09+1.94 [-0.45, 5.04]5.32 [4.61, 6.23]8% [0%, 17%]23%31%-0.11+0.012026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC4.56 [3.88, 5.53]4.09+1.94 [-0.56, 5.02]5.32 [4.59, 6.15]8% [0%, 17%]23%31%-0.11+0.012026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC4.56 [3.82, 5.72]4.09+1.94 [-0.68, 5.45]5.32 [4.54, 6.39]8% [0%, 17%]23%31%-0.11+0.012026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC4.76 [3.93, 5.85]4.27+2.31 [-0.21, 5.08]5.67 [4.96, 6.55]12% [3%, 20%]27%38%-0.16-0.042026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC4.76 [3.92, 6.12]4.27+2.31 [-0.04, 5.68]5.67 [4.93, 6.72]12% [0%, 21%]27%38%-0.16-0.042026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC4.76 [3.94, 6.00]4.27+2.31 [-0.22, 5.70]5.67 [4.95, 6.68]12% [0%, 21%]27%38%-0.16-0.042026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC4.76 [3.94, 6.21]4.27+2.31 [-0.27, 6.11]5.67 [4.89, 6.81]12% [0%, 21%]27%38%-0.16-0.042026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC3.57 [2.29, 4.84]3.55+0.13 [-2.71, 2.53]4.58 [2.92, 5.81]23% [9%, 39%]35%46%+0.16+0.152026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC3.57 [2.09, 5.03]3.55+0.13 [-2.71, 2.76]4.58 [2.71, 5.96]23% [7%, 44%]35%46%+0.16+0.152026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC3.57 [1.97, 5.08]3.55+0.13 [-3.04, 2.75]4.58 [2.62, 6.06]23% [8%, 44%]35%46%+0.16+0.152026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC3.57 [2.03, 5.05]3.55+0.13 [-2.99, 2.89]4.58 [2.59, 5.99]23% [6%, 42%]35%46%+0.16+0.152026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC3.92 [2.76, 5.00]3.74+1.07 [-1.69, 3.60]4.79 [3.39, 6.06]12% [4%, 18%]27%42%+0.07+0.112026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC3.92 [2.68, 5.15]3.74+1.07 [-1.70, 3.94]4.79 [3.25, 6.26]12% [0%, 17%]27%42%+0.07+0.112026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC3.92 [2.51, 5.23]3.74+1.07 [-1.99, 3.88]4.79 [3.14, 6.37]12% [0%, 17%]27%42%+0.07+0.112026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC3.92 [2.67, 5.18]3.74+1.07 [-2.00, 4.00]4.79 [3.25, 6.27]12% [0%, 17%]27%42%+0.07+0.112026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC2.48 [1.72, 3.13]2.48+0.10 [-1.69, 1.72]3.23 [2.30, 3.87]35% [23%, 48%]54%62%+0.41+0.412026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC2.48 [1.56, 3.15]2.48+0.10 [-1.69, 1.98]3.23 [2.11, 3.91]35% [23%, 50%]54%62%+0.41+0.412026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC2.48 [1.48, 3.17]2.48+0.10 [-1.94, 2.03]3.23 [1.93, 3.92]35% [24%, 50%]54%62%+0.41+0.412026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC2.48 [1.45, 3.17]2.48+0.10 [-1.95, 1.97]3.23 [1.85, 3.93]35% [22%, 50%]54%62%+0.41+0.412026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC2.93 [2.14, 3.74]2.74+1.47 [-0.37, 3.15]3.65 [2.73, 4.41]23% [7%, 46%]42%62%+0.31+0.352026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC2.93 [2.02, 3.87]2.74+1.47 [-0.36, 3.53]3.65 [2.58, 4.46]23% [4%, 50%]42%62%+0.31+0.352026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC2.93 [1.91, 3.89]2.74+1.47 [-0.49, 3.51]3.65 [2.47, 4.49]23% [0%, 55%]42%62%+0.31+0.352026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC2.93 [1.89, 3.89]2.74+1.47 [-0.65, 3.51]3.65 [2.42, 4.46]23% [0%, 52%]42%62%+0.31+0.352026-08-05 → 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 KMSP, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: +0.68 °F2026-08-06: +8.09 °F2026-08-07: +9.04 °F2026-08-08: -1.1 °F2026-08-09: +1.95 °F2026-08-10: -1.09 °F2026-08-11: +1.02 °F2026-08-12: -2.15 °F2026-08-13: -1.26 °F2026-08-14: -3.21 °F2026-08-15: -7.35 °F2026-08-16: +1.05 °F2026-08-17: +2.68 °F2026-08-18: -7.11 °F2026-08-19: -3.13 °F2026-08-20: -6.7 °F2026-08-21: -3.85 °F2026-08-22: +4.16 °F2026-08-23: +1.06 °F2026-08-24: -15.38 °F2026-08-25: +0.59 °F2026-08-26: -2.13 °F2026-08-27: -0.57 °F2026-08-28: -2.09 °F2026-08-29: +2.64 °F2026-08-30: +8.93 °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+8.93
2026-08-29+2.64
2026-08-28-2.09
2026-08-27-0.57
2026-08-26-2.13
2026-08-25+0.59
2026-08-24-15.38
2026-08-23+1.06
2026-08-22+4.16
2026-08-21-3.85
2026-08-20-6.70
2026-08-19-3.13
2026-08-18-7.11
2026-08-17+2.68
2026-08-16+1.05
2026-08-15-7.35
2026-08-14-3.21
2026-08-13-1.26
2026-08-12-2.15
2026-08-11+1.02
2026-08-10-1.09
2026-08-09+1.95
2026-08-08-1.10
2026-08-07+9.04
2026-08-06+8.09
2026-08-05+0.68

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KMSP, 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: 0 days-8 to -6 °F: 3 days-6 to -4 °F: 0 days-4 to -2 °F: 6 days-2 to 0 °F: 4 days0 to 2 °F: 6 days2 to 4 °F: 2 days4 to 6 °F: 1 day6 to 8 °F: 0 days8 to 10 °F: 3 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| 2.4 · P90 |e| 8.51 °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
-10.00-8.000
-8.00-6.003
-6.00-4.000
-4.00-2.006
-2.00+0.004
+0.00+2.006
+2.00+4.002
+4.00+6.001
+6.00+8.000
+8.00+10.003
+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 -0.59

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 -0.21 [-1.37, 1.33] no
GraphCast (IFS init) 25 -2.44 [-4.21, -0.59] yes
ECMWF IFS HRES 20 +0.48 [-2.23, 1.90] no
Persistence (baseline) 26 -0.31 [-2.63, 1.88] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KMSP (Minneapolis-St Paul), 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/KMSP/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