A small tropical disturbance in the Intertropical Convergence Zone became a closed low on October 4 and organized into Tropical Depression Eleven by 0600 UTC October 6 about 735 nautical miles south‑southwest of Cabo San Lucas, Mexico. The system strengthened to Tropical Storm Irwin within six hours and moved generally west‑northwestward for several days. After interacting with a mid‑latitude trough and a large cyclonic gyre, Irwin turned northward and northeastward, weakened, fluctuated between tropical storm and depression strength, drifted southward briefly, and finally degenerated to a remnant low on October 16. The remnant low dissipated about 1200 UTC October 18 roughly 355 nautical miles southwest of Manzanillo.
Irwin did not make any landfalls on the Mexican coast or elsewhere. The cyclone remained well offshore for its entire life and no coastal watches or warnings were issued.
The maximum analyzed intensity occurred at 1800 UTC October 7, when Irwin reached peak sustained winds of 85 knots (approximately 98 mph) and a minimum central pressure of 977 millibars, making it a Category 2 hurricane at peak. Irwin was a hurricane only briefly; it spent most of its life at tropical storm or weaker strength.
Because Irwin stayed well offshore, there were no reports of storm surge or rainfall impacts to Mexican cities or counties in the official record and no specific surge heights or rainfall totals were reported by the National Hurricane Center. Ship observations did record gusts and sustained winds of tropical‑storm force from vessels near the circulation, though some ship reports were later adjusted downward after quality control.
There were no reported deaths or damage associated with Irwin. The storm’s formation was well anticipated by forecast products, and the National Hurricane Center’s track forecasts were generally skillful compared with typical guidance despite Irwin’s unusual, slow, meandering track. Short‑range intensity forecasts were more challenging because of a rapid 2–3 day period of both rapid strengthening and rapid weakening early in the storm’s life.
Paid members can generate summaries tailored to the counties of their choice. The Irwin TCR covers impacts across many counties and states — a Pinellas County resident doesn't need the Asheville detail, and a Buncombe County resident doesn't need the Tampa surge data.
Upgrade for county-specific summariesSummary above produced from the National Hurricane Center's official post-storm Tropical Cyclone Report. Read the full report for casualty lists, damage estimates by area, forecast critique, and detailed meteorological discussion:
📄 Read NHC's full report on Irwin → (opens at nhc.noaa.gov)| Time (UTC) | Status | Lat | Lon | Winds (kt) | Pressure (mb) | Record |
|---|---|---|---|---|---|---|
| 2011-10-04 18:00 | LO | 11.60 | -111.70 | 25 | 1009 | |
| 2011-10-05 00:00 | LO | 11.50 | -112.60 | 25 | 1009 | |
| 2011-10-05 06:00 | LO | 11.40 | -113.20 | 25 | 1009 | |
| 2011-10-05 12:00 | LO | 11.40 | -113.90 | 25 | 1009 | |
| 2011-10-05 18:00 | LO | 11.60 | -114.60 | 25 | 1009 | |
| 2011-10-06 00:00 | LO | 11.90 | -115.30 | 25 | 1007 | |
| 2011-10-06 06:00 | TD | 12.10 | -116.00 | 30 | 1006 | |
| 2011-10-06 12:00 | TS | 12.30 | -116.70 | 35 | 1004 | |
| 2011-10-06 18:00 | TS | 12.50 | -117.60 | 50 | 999 | |
| 2011-10-07 00:00 | TS | 12.90 | -118.50 | 60 | 995 | |
| 2011-10-07 06:00 | HU | 13.30 | -119.30 | 70 | 989 | |
| 2011-10-07 12:00 | HU | 13.60 | -120.00 | 80 | 981 | |
| 2011-10-07 18:00 | HU | 13.80 | -120.50 | 85 | 977 | |
| 2011-10-08 00:00 | HU | 13.90 | -120.80 | 85 | 976 | |
| 2011-10-08 06:00 | HU | 14.10 | -121.00 | 80 | 980 | |
| 2011-10-08 12:00 | HU | 14.30 | -121.00 | 70 | 985 | |
| 2011-10-08 18:00 | TS | 14.40 | -120.90 | 60 | 991 | |
| 2011-10-09 00:00 | TS | 14.60 | -120.70 | 45 | 1001 | |
| 2011-10-09 06:00 | TS | 14.90 | -120.40 | 35 | 1004 | |
| 2011-10-09 12:00 | TS | 15.10 | -120.00 | 35 | 1004 | |
| 2011-10-09 18:00 | TS | 15.20 | -119.60 | 40 | 1003 | |
| 2011-10-10 00:00 | TS | 15.20 | -119.10 | 40 | 1003 | |
| 2011-10-10 06:00 | TS | 15.20 | -118.50 | 40 | 1003 | |
| 2011-10-10 12:00 | TS | 15.20 | -117.90 | 40 | 1003 | |
| 2011-10-10 18:00 | TS | 15.10 | -117.20 | 40 | 1003 | |
| 2011-10-11 00:00 | TS | 15.10 | -116.50 | 35 | 1004 | |
| 2011-10-11 06:00 | TS | 15.10 | -115.90 | 35 | 1004 | |
| 2011-10-11 12:00 | TS | 15.00 | -115.30 | 40 | 1003 | |
| 2011-10-11 18:00 | TS | 14.80 | -114.50 | 45 | 1001 | |
| 2011-10-12 00:00 | TS | 14.80 | -113.60 | 45 | 1001 | |
| 2011-10-12 06:00 | TS | 15.00 | -112.50 | 40 | 1002 | |
| 2011-10-12 12:00 | TS | 15.60 | -111.20 | 40 | 1002 | |
| 2011-10-12 18:00 | TS | 16.50 | -110.00 | 35 | 1003 | |
| 2011-10-13 00:00 | TD | 17.40 | -108.90 | 30 | 1004 | |
| 2011-10-13 06:00 | TD | 18.10 | -108.10 | 30 | 1004 | |
| 2011-10-13 12:00 | TD | 18.60 | -107.50 | 30 | 1004 | |
| 2011-10-13 18:00 | TS | 19.00 | -106.80 | 35 | 1003 | |
| 2011-10-14 00:00 | TS | 19.20 | -106.70 | 35 | 1002 | |
| 2011-10-14 06:00 | TS | 19.20 | -106.80 | 35 | 1002 | |
| 2011-10-14 12:00 | TS | 18.90 | -106.90 | 40 | 1002 | |
| 2011-10-14 18:00 | TS | 18.50 | -106.80 | 40 | 1003 | |
| 2011-10-15 00:00 | TS | 18.00 | -106.40 | 40 | 1003 | |
| 2011-10-15 06:00 | TS | 17.40 | -106.30 | 35 | 1003 | |
| 2011-10-15 12:00 | TS | 16.70 | -106.40 | 35 | 1003 | |
| 2011-10-15 18:00 | TD | 15.80 | -106.70 | 30 | 1004 | |
| 2011-10-16 00:00 | TD | 15.10 | -107.00 | 30 | 1004 | |
| 2011-10-16 06:00 | TD | 14.50 | -107.20 | 30 | 1005 | |
| 2011-10-16 12:00 | TD | 13.90 | -107.50 | 30 | 1006 | |
| 2011-10-16 18:00 | LO | 13.70 | -107.90 | 30 | 1006 | |
| 2011-10-17 00:00 | LO | 13.90 | -108.20 | 25 | 1007 | |
| 2011-10-17 06:00 | LO | 14.30 | -108.50 | 25 | 1007 | |
| 2011-10-17 12:00 | LO | 14.90 | -108.70 | 20 | 1008 | |
| 2011-10-17 18:00 | LO | 15.40 | -109.00 | 15 | 1009 | |
| 2011-10-18 00:00 | LO | 15.60 | -109.50 | 15 | 1009 | |
| 2011-10-18 06:00 | LO | 15.80 | -109.60 | 15 | 1010 | |
| 2011-10-18 12:00 | LO | 15.60 | -109.50 | 15 | 1010 |
Source: NOAA National Hurricane Center HURDAT2 best-track database (nhc.noaa.gov/data). Data is in the public domain. Best-track positions and intensities are post-storm reanalysis estimates and may differ from real-time advisories.