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Days 1–5. Compared with the National Weather Service forecast from the same hour. No one pays for a rank.

Hurricane tracks

Post-Tropical Cyclone Erin Model Accuracy: GFS vs GEFS mean vs Canadian GEM

Final advisory

NHC issued its final advisory at 2:00 PM ET Fri, Aug 22; Erin is now a post-tropical cyclone.

Post-Tropical Cyclone Erin has 68 positions on the best track, which is where the storm actually went, from the operational NHC file. 4 official forecast tracks are drawn. At 48 hours, the average track miss is 74 miles across 46 forecasts. At 48 hours, the official wind forecast averaged 103 mph and where the storm actually went averaged 98 mph. Stored model tracks on these forecast tracks: GFS, GEFS mean, Canadian GEM, UKMET, HAFS-A, HAFS-B, HWRF, HMON, NAVGEM.

AL052025 · 2025 · Aug 11-27, 2025. Score table. Damage reports.

How to read this. The solid line is where the storm went. A dashed line is where the official forecast said it would go. A smaller path miss is closer. Distances are statute miles. Wind speeds are miles per hour.

The technical details

Path miss on this page is the great-circle distance in statute miles, the same miles as the home card and the score table. The Earth radius is 3,958.7613 miles. The file also keeps that distance in nautical miles. One nautical mile is 1,852 meters, about 1.15 statute miles. A case counts when that forecast and the best track (BEST, lead 0) share the same valid time. Positions are not interpolated. A model track counts even when that cycle has no official forecast yet. Skill against the official forecast (OFCL) still requires the official forecast from the same issue time and lead.

Shown leads are 12, 24, 36, 48, 60, 72, 96, and 120 hours, once a paired fix exists. Sample size is the number of paired cases at that lead. Overall rank still uses 24, 48, 72, and 120 hours. The 96-hour lead is drawn when the deck has a paired fix, and it is not in that rank.

Wind on this page is miles per hour. The file stores maximum wind in knots. One knot is about 1.15 miles per hour. An advisory wind is rounded to the nearest 5 mph. A mean on this page is rounded to the nearest mile per hour. Wind miss is the absolute difference on the paired cases. There is no confidence interval on this map. The daily board’s interval is a 95% percentile bootstrap.

Overall rank is the average of the path rank and the wind rank on this storm. Each rank uses the graded leads at 24, 48, 72, and 120 hours, and each of those leads counts once, however many forecasts it holds. A lower miss is the better rank. A tie shares the average of the places those forecasts occupy. A source is ranked only with at least 3 graded forecasts for path and 3 for wind. Fewer than that says Not enough forecasts yet. A source with no graded path, or no graded wind, is left out of both ranks, and overall shows —.

The best track is the operational NHC b-deck. It is preliminary and revised after the season. HURDAT2 is not loaded. Model lines come from the public a-deck for the same forecast tracks, and only when that file stores them. Google DeepMind is the Weather Lab operational ensemble mean. WeatherNext 3 is that model’s ensemble mean from the same download. ECMWF AIFS, ECMWF HRES, and the ECMWF ENS mean are tropical-cyclone tracks from ECMWF open data. The ECMWF ENS mean is the average of the member centers in the IFS ensemble track file. AI GFS is NOAA’s AIGFS tracker when that file is still posted. The methodology page names the aids that are scored.

The methodology page is the full reference. How we grade says the same rules in plain English.

The best track is the operational NHC b-deck. It is preliminary and is revised after the season. The post-season HURDAT2 track is not loaded.

This score uses the archived NHC b-deck and a-deck for this storm. The post-season HURDAT2 file is not loaded.

Google DeepMind, WeatherNext 3, ECMWF AIFS, ECMWF HRES, ECMWF ENS mean, AI GFS: No graded forecasts yet.

Overall rank

Overall averages each forecast's rank on path and on wind strength. See the separate scores below.

Place on this list. 1 was closest to the weather that happened. A tie shares this number, and the next place skips ahead. Early read until the longer day count, then proven. The forecast source this row scores. Path and wind ranksOverall averages each forecast's rank on path and on wind strength. See the separate scores below. Track rankPlace on path miss. 1 was closest. On one storm this is that place. Across storms it is the average of those places. Each graded lead counts once. A tie shares the average place. Intensity rankPlace on wind miss. 1 was closest. On one storm this is that place. Across storms it is the average of those places. Each graded lead counts once. A tie shares the average place.
1 HMON 2.5 3 2
2 HWRF 3 2 4
3 NHC official 3.5 6 1
4 GEFS mean 4 1 7
5 HAFS-A 4.5 4 5
6 GFS 5 7 3
7 HAFS-B 5.5 5 6
8 Canadian GEM 9 8 10
8 NAVGEM 9 10 8
8 UKMET 9 9 9

How we grade

Track and intensity by model

Each row is one source at one lead that has already verified, including 12, 24, 36, and 48 hours. The count is how many forecasts shared a time with where the storm went. Path miss is statute miles. Wind miss is miles per hour. The rank number is that source's place in the table above, and it still uses 24, 48, 72, and 120 hours.

Place on this list. 1 was closest to the weather that happened. A tie shares this number, and the next place skips ahead. Early read until the longer day count, then proven. The forecast source this row scores. LeadHow many hours ahead this forecast was made. Scored leads are 24, 48, 72, and 120. The technical name is lead. CasesHow many past forecasts went into this average. A forecast counts only when the best track has a fix at that exact time. The technical name is cases. Track errorAverage how far the predicted storm path was from where it actually went, in miles. Lower is better. The technical name is track error. Track skillHow that path miss compares with the official hurricane forecast. Positive means better than the official forecast. Negative means worse. The technical name is track skill. Intensity errorAverage how far off the predicted wind speed was, in miles per hour. The file stores knots. Lower is better. The technical name is intensity error. Intensity skillHow that wind miss compares with the official hurricane forecast. Positive means better. Negative means worse. The technical name is intensity skill.
1 HMON 12 h 49 25 mi Behind the official forecast by 22% 15 mph Behind the official forecast by 91%
1 HMON 24 h 51 47 mi Behind the official forecast by 30% 17 mph Behind the official forecast by 48%
1 HMON 36 h 50 67 mi Behind the official forecast by 31% 14 mph Behind the official forecast by 4%
1 HMON 48 h 48 91 mi Behind the official forecast by 27% 12 mph Beats the official forecast by 8%
1 HMON 60 h 46 115 mi Behind the official forecast by 19% 15 mph Behind the official forecast by 8%
1 HMON 72 h 45 141 mi Behind the official forecast by 8% 15 mph Beats the official forecast by 1%
1 HMON 96 h 40 177 mi Ties the official forecast 16 mph Ties the official forecast
1 HMON 120 h 37 234 mi Behind the official forecast by 5% 17 mph Behind the official forecast by 16%
2 HWRF 12 h 49 25 mi Behind the official forecast by 26% 13 mph Behind the official forecast by 62%
2 HWRF 24 h 51 44 mi Behind the official forecast by 22% 14 mph Behind the official forecast by 24%
2 HWRF 36 h 52 70 mi Behind the official forecast by 29% 15 mph Behind the official forecast by 24%
2 HWRF 48 h 52 95 mi Behind the official forecast by 21% 15 mph Behind the official forecast by 30%
2 HWRF 60 h 52 126 mi Behind the official forecast by 19% 16 mph Behind the official forecast by 22%
2 HWRF 72 h 52 145 mi Behind the official forecast by 4% 17 mph Behind the official forecast by 8%
2 HWRF 96 h 52 190 mi Beats the official forecast by 12% 17 mph Behind the official forecast by 10%
2 HWRF 120 h 52 220 mi Beats the official forecast by 32% 18 mph Behind the official forecast by 43%
3 NHC official 12 h 46 19 mi — 8 mph —
3 NHC official 24 h 46 35 mi — 12 mph —
3 NHC official 36 h 46 51 mi — 13 mph —
3 NHC official 48 h 46 74 mi — 13 mph —
3 NHC official 60 h 46 99 mi — 15 mph —
3 NHC official 72 h 46 126 mi — 16 mph —
3 NHC official 96 h 46 192 mi — 15 mph —
3 NHC official 120 h 46 289 mi — 12 mph —
4 GEFS mean 12 h 50 23 mi Behind the official forecast by 13% 25 mph Behind the official forecast by 208%
4 GEFS mean 24 h 52 43 mi Behind the official forecast by 14% 22 mph Behind the official forecast by 89%
4 GEFS mean 36 h 53 64 mi Behind the official forecast by 21% 21 mph Behind the official forecast by 66%
4 GEFS mean 48 h 53 83 mi Behind the official forecast by 12% 20 mph Behind the official forecast by 65%
4 GEFS mean 60 h 53 104 mi Behind the official forecast by 8% 20 mph Behind the official forecast by 47%
4 GEFS mean 72 h 53 123 mi Ties the official forecast 20 mph Behind the official forecast by 32%
4 GEFS mean 96 h 53 154 mi Beats the official forecast by 19% 21 mph Behind the official forecast by 46%
4 GEFS mean 120 h 53 210 mi Beats the official forecast by 26% 21 mph Behind the official forecast by 64%
5 HAFS-A 12 h 49 22 mi Behind the official forecast by 10% 16 mph Behind the official forecast by 95%
5 HAFS-A 24 h 51 41 mi Behind the official forecast by 16% 17 mph Behind the official forecast by 37%
5 HAFS-A 36 h 52 59 mi Behind the official forecast by 15% 17 mph Behind the official forecast by 42%
5 HAFS-A 48 h 52 74 mi Behind the official forecast by 4% 18 mph Behind the official forecast by 55%
5 HAFS-A 60 h 52 96 mi Ties the official forecast 18 mph Behind the official forecast by 37%
5 HAFS-A 72 h 52 115 mi Beats the official forecast by 9% 17 mph Behind the official forecast by 10%
5 HAFS-A 96 h 52 166 mi Beats the official forecast by 17% 16 mph Behind the official forecast by 15%
5 HAFS-A 120 h 52 242 mi Beats the official forecast by 16% 15 mph Behind the official forecast by 12%
6 GFS 12 h 50 25 mi Behind the official forecast by 15% 21 mph Behind the official forecast by 153%
6 GFS 24 h 52 45 mi Behind the official forecast by 23% 19 mph Behind the official forecast by 54%
6 GFS 36 h 53 64 mi Behind the official forecast by 26% 15 mph Behind the official forecast by 18%
6 GFS 48 h 53 84 mi Behind the official forecast by 17% 15 mph Behind the official forecast by 16%
6 GFS 60 h 53 108 mi Behind the official forecast by 14% 14 mph Beats the official forecast by 2%
6 GFS 72 h 53 133 mi Behind the official forecast by 9% 15 mph Beats the official forecast by 2%
6 GFS 96 h 53 178 mi Beats the official forecast by 5% 16 mph Behind the official forecast by 15%
6 GFS 120 h 53 264 mi Beats the official forecast by 6% 15 mph Behind the official forecast by 35%
7 HAFS-B 12 h 49 24 mi Behind the official forecast by 21% 15 mph Behind the official forecast by 85%
7 HAFS-B 24 h 51 45 mi Behind the official forecast by 30% 15 mph Behind the official forecast by 26%
7 HAFS-B 36 h 52 64 mi Behind the official forecast by 27% 15 mph Behind the official forecast by 21%
7 HAFS-B 48 h 52 80 mi Behind the official forecast by 12% 17 mph Behind the official forecast by 40%
7 HAFS-B 60 h 52 104 mi Behind the official forecast by 9% 16 mph Behind the official forecast by 22%
7 HAFS-B 72 h 52 125 mi Beats the official forecast by 1% 19 mph Behind the official forecast by 27%
7 HAFS-B 96 h 52 172 mi Beats the official forecast by 12% 18 mph Behind the official forecast by 12%
7 HAFS-B 120 h 52 249 mi Beats the official forecast by 12% 19 mph Behind the official forecast by 43%
8 UKMET 12 h 25 27 mi Behind the official forecast by 29% 29 mph Behind the official forecast by 304%
8 UKMET 24 h 26 38 mi Behind the official forecast by 9% 27 mph Behind the official forecast by 161%
8 UKMET 36 h 25 51 mi Behind the official forecast by 1% 24 mph Behind the official forecast by 108%
8 UKMET 48 h 23 65 mi Beats the official forecast by 5% 21 mph Behind the official forecast by 96%
8 UKMET 60 h 22 89 mi Beats the official forecast by 5% 39 mph Behind the official forecast by 204%
8 UKMET 72 h 21 122 mi Behind the official forecast by 1% 25 mph Behind the official forecast by 173%
8 UKMET 96 h 20 191 mi Ties the official forecast 39 mph Behind the official forecast by 150%
8 UKMET 120 h 20 342 mi Behind the official forecast by 14% 38 mph Behind the official forecast by 192%
8 Canadian GEM 12 h 25 31 mi Behind the official forecast by 59% 32 mph Behind the official forecast by 321%
8 Canadian GEM 24 h 26 47 mi Behind the official forecast by 31% 33 mph Behind the official forecast by 218%
8 Canadian GEM 36 h 26 69 mi Behind the official forecast by 31% 33 mph Behind the official forecast by 176%
8 Canadian GEM 48 h 26 94 mi Behind the official forecast by 28% 33 mph Behind the official forecast by 175%
8 Canadian GEM 60 h 26 116 mi Behind the official forecast by 17% 34 mph Behind the official forecast by 156%
8 Canadian GEM 72 h 26 145 mi Behind the official forecast by 13% 33 mph Behind the official forecast by 117%
8 Canadian GEM 96 h 25 199 mi Behind the official forecast by 17% 33 mph Behind the official forecast by 112%
8 Canadian GEM 120 h 25 240 mi Beats the official forecast by 3% 35 mph Behind the official forecast by 195%
8 NAVGEM 12 h 49 42 mi Behind the official forecast by 98% 25 mph Behind the official forecast by 203%
8 NAVGEM 24 h 51 58 mi Behind the official forecast by 56% 24 mph Behind the official forecast by 102%
8 NAVGEM 36 h 52 79 mi Behind the official forecast by 55% 24 mph Behind the official forecast by 89%
8 NAVGEM 48 h 51 107 mi Behind the official forecast by 46% 27 mph Behind the official forecast by 117%
8 NAVGEM 60 h 51 130 mi Behind the official forecast by 36% 28 mph Behind the official forecast by 102%
8 NAVGEM 72 h 51 151 mi Behind the official forecast by 21% 28 mph Behind the official forecast by 84%
8 NAVGEM 96 h 51 224 mi Behind the official forecast by 19% 27 mph Behind the official forecast by 95%
8 NAVGEM 120 h 51 306 mi Behind the official forecast by 10% 26 mph Behind the official forecast by 130%

How we grade

Google DeepMind, WeatherNext 3, ECMWF AIFS, ECMWF HRES, ECMWF ENS mean, AI GFS: No graded forecasts yet.

Track map

The solid line is the best track. Dashed lines are official forecast tracks from a few advisories, from the issue position out through the leads stored in that advisory. Thinner lines are model tracks from NHC’s public a-deck for those same advisories, and only when that file actually contains them. Google DeepMind and WeatherNext 3 are ensemble-mean tracks from Weather Lab, drawn on those same advisories. ECMWF AIFS, ECMWF HRES, and the ECMWF ENS mean are open-data cyclone tracks, drawn the same way. AI GFS is NOAA’s AIGFS tracker, drawn when that file is still posted.

10°N 29°N 49°N 68°N 86°W 52°W 17°W 17°E
Map of Post-Tropical Cyclone Erin. The best track, where the storm actually went, has 68 positions. 4 official forecast tracks are drawn. Model lines: GFS, GEFS mean, Canadian GEM, UKMET, HAFS-A, HAFS-B, HWRF, HMON, NAVGEM. Latitude and longitude, scaled by the cosine of the mid-latitude so a degree of longitude is not stretched.
  • Actual track (68 positions)
  • NHC official Aug 11, 12:00 UTC
  • NHC official Aug 15, 06:00 UTC
  • NHC official Aug 19, 00:00 UTC
  • NHC official Aug 22, 18:00 UTC
  • GFS
  • GEFS mean
  • Canadian GEM
  • UKMET
  • HAFS-A
  • HAFS-B
  • HWRF
  • HMON
  • NAVGEM

The chart measures how far the track was off in statute miles, the same miles as the home card. It includes 12, 24, 36, 48, 60, 72, 96, and 120 hours when a paired fix exists. The overall rank uses 24, 48, 72, and 120 hours. Positions are not interpolated.

How far the track was off

19 mi 12 h 35 mi 24 h 51 mi 36 h 74 mi 48 h 99 mi 60 h 126 mi 72 h 192 mi 96 h 289 mi 120 h
Average official track miss in miles by how far ahead. 12 hours 19 miles over 46 forecasts. 24 hours 35 miles over 46 forecasts. 36 hours 51 miles over 46 forecasts. 48 hours 74 miles over 46 forecasts. 60 hours 99 miles over 46 forecasts. 72 hours 126 miles over 46 forecasts. 96 hours 192 miles over 46 forecasts. 120 hours 289 miles over 46 forecasts.
LeadHow many hours ahead this forecast was made. This map shows 12, 24, 36, 48, 60, 72, 96, and 120 when a paired fix exists. Overall rank uses 24, 48, 72, and 120. The technical name is lead. CasesHow many past forecasts went into this average. A forecast counts only when the best track has a fix at that exact time. The technical name is cases. Track errorAverage how far the predicted storm path was from where it actually went, in statute miles. Lower is better. The technical name is track error. Intensity errorAverage how far off the predicted wind speed was, in miles per hour, on this page. Lower is better. The file stores knots. The technical name is intensity error. Forecast max windAverage top wind in the official forecast, in miles per hour, on the paired cases. The file stores knots. The technical name is forecast maximum wind. Best-track windAverage top wind where the storm actually went, in miles per hour, at the same times. The file stores knots. The technical name is best-track wind.
12 h 46 19 mi 8 mph 96 mph 92 mph
24 h 46 35 mi 12 mph 99 mph 94 mph
36 h 46 51 mi 13 mph 102 mph 96 mph
48 h 46 74 mi 13 mph 103 mph 98 mph
60 h 46 99 mi 15 mph 104 mph 99 mph
72 h 46 126 mi 16 mph 102 mph 99 mph
96 h 46 192 mi 15 mph 98 mph 98 mph
120 h 46 289 mi 12 mph 93 mph 94 mph

Miles are statute miles. Wind is miles per hour. The National Hurricane Center file stores wind in knots. One knot is about 1.15 miles per hour. Nautical miles are in the technical details.

How we grade

Top wind

12 h 24 h 36 h 48 h 60 h 72 h 96 h 120 h
Top wind, official forecast versus where the storm went. At 12 hours the forecast averaged 96 mph and where the storm actually went averaged 92 mph. At 24 hours the forecast averaged 99 mph and where the storm actually went averaged 94 mph. At 36 hours the forecast averaged 102 mph and where the storm actually went averaged 96 mph. At 48 hours the forecast averaged 103 mph and where the storm actually went averaged 98 mph. At 60 hours the forecast averaged 104 mph and where the storm actually went averaged 99 mph. At 72 hours the forecast averaged 102 mph and where the storm actually went averaged 99 mph. At 96 hours the forecast averaged 98 mph and where the storm actually went averaged 98 mph. At 120 hours the forecast averaged 93 mph and where the storm actually went averaged 94 mph.
  • Official forecast maximum wind
  • Best-track maximum wind

Source: National Hurricane Center / NOAA. The operational b-deck and the public a-deck are U.S. government works in the public domain. Google DeepMind and WeatherNext 3 ensemble means are experimental forecasts from Google DeepMind Weather Lab. Forecasts older than 48 hours are used under CC BY 4.0. ECMWF AIFS, ECMWF HRES, and ECMWF ENS tracks are ECMWF open data, used under CC BY 4.0. AI GFS tracks are a NOAA AIGFS product. Forecast Scoreboard is not affiliated with NHC, NOAA, Google, or ECMWF.