Daily Routing Brief — 2026-05-31
Generated 2026-05-31T18:57:20.651828+00:00 · Newport→Bermuda 2026 · T−19 days · « all briefs
Regime: PRACTICE + OCEAN-TRACKING — T−19 days. No atmospheric model reaches race day yet (~7-day horizon). The codes below are crew practice, not a June-19 forecast. The genuinely predictive signal this far out is the Gulf Stream — track its evolution below.
PRE-RACE PRACTICE ONLY — not for use during the race
These are pre-race research / practice reps. Per RRS 41 (2026 NOR) a boat shall not receive routing assistance from shore — including AI-generated — while racing. This page stops updating before the June 19 start; do not open it from the boat once racing.
Headline
Current forecast window most resembles 2012 (W-PF/W-BH/W-BH, score 2.55).
- Winner that year: Carina (Reichel/Pugh design) — line honors basis
- What won: Simple execution near rhumb; ~2 jibes + 2 tacks for 636 nm
- Winning tactics: T-RH T-PF T-CL
- Lesson: Benign Stream year. Execution beats positioning. Low maneuver count wins reaching races.
- Best corridor that year: RHUMB
Per-period classification (current window)
Start anchor: 2026-05-31T00:00:00+00:00 · horizon +167 h
| period | code | conf | GFS wind/gust | ECMWF wind/gust | ICON wind/gust |
|---|---|---|---|---|---|
| P1 start / coastal | W-CF | HIGH (100%) | 25.1/42.2 kn | 24.6/44.1 kn | 24.5/50.7 kn |
| P2 Gulf Stream crossing | W-BH | HIGH (100%) | 18.7/22.9 kn | 12.6/21.0 kn | 9.9/16.1 kn |
| P3 Bermuda approach | W-PF | MEDIUM (67%) | 10.2/22.2 kn | 13.7/28.6 kn | 8.4/16.3 kn |
Codes are atmospheric only and link to the analog framework. Wind/gust in knots. Confidence = model agreement. See the method.
Trend (day over day)
vs 2026-05-30 (T−20):
- Headline analog held: 2012.
- Period codes: P1 W-PF→W-CF.
- Model agreement: 89% → 89%.
- Gulf Stream snapshot unchanged (2026-05-31).
- Crossing SST: 22.3→22.0 °C ↓, north-wall jump +6.2°C.
- Peak corridor wave: 2.0→3.8 m ↑.
Convergence: race day not yet in model horizon — convergence tracking begins automatically once it is (~T−7).
Analog ranking (period-aware)
| rank | year | score | P1/P2/P3 | best corridor |
|---|---|---|---|---|
| 1 | 2012 | 2.55 | W-PF/W-BH/W-BH | RHUMB |
2014 excluded as seed data. Years link to their winner-route writeups.
Gulf Stream (observed — the real signal this far out)
Latest local snapshot: 2026-05-31 (1 days old)
Clearest satellite SST pass for 2026-05-31 (Rutgers RUCOOL). Full imagery set + Frank Bohlen's note: data/gulfstream-monitor/2026-05-31/.
A cold-core ring or meander near the rhumb persists for weeks, so today's Stream state genuinely informs June 19 — see the corridor decision page. Stream codes (W-RC/W-CC/W-WE/W-AC) come from this observed data, not the atmospheric forecast.
Crossing corridor with the 2026-05-30 Stream walls + eddy (1 day old), frozen for this brief.
Full interactive planning map — all six past corrected-time winners' tracks over the corridor (toggle layers).
Data sources
- Forecast (wind · gust · pressure — GFS·ECMWF·ICON): Open-Meteo · full list in the Sources & Tools catalog.
- Gulf Stream SST: NOAA OPC NCOM · Rutgers RUCOOL · NASA SPoRT.
- Gulf Stream currents: NOAA OPC RTOFS · AOML altimetry.
- Expert read: Frank Bohlen's Gulf Stream notes.
Sea state & ocean (numeric — Open-Meteo Marine)
Near-term (next 24 h) means along the corridor. SST and waves are reliable; ocean current is a COARSE model that understates the Gulf Stream (2–4 kn) and cannot see rings or meanders — trust the Stream imagery for structure.
| waypoint | SST | current | wave |
|---|---|---|---|
| start | 12.2 °C / 54 °F | 0.5 kn @ 226° | 2.1 m / 8 s |
| shelf | 15.8 °C / 60 °F | 0.4 kn @ 187° | 3.3 m / 8 s |
| stream | 22.0 °C / 72 °F | 0.4 kn @ 200° | 3.8 m / 8 s |
| post_stream | 22.0 °C / 72 °F | 0.4 kn @ 214° | 2.8 m / 8 s |
| approach | 22.9 °C / 73 °F | 0.5 kn @ 163° | 1.9 m / 8 s |
North wall: SST jumps +6.2 °C from the shelf (15.8 °C) to the crossing (22.0 °C) — a clear Gulf Stream front signature.
Sea state: peak corridor wave ~3.8 m.
Race-day horizon
Race day is T−19 — beyond the ~7-day model horizon. The classifier correctly declines (no fabricated race-day codes). Convergence tracking begins automatically when race day enters the window (~T−7).
Sources: forecast — Open-Meteo (GFS/ECMWF/ICON, no key). Analogs — framework + winner routes + tactics. Gulf Stream — scripts/gulfstream_monitor. Method — forecast analog matcher. Pipeline — scripts/daily_brief.py.