Daily Routing Brief — 2026-05-29
Generated 2026-05-29T18:32:40.835872+00:00 · Newport→Bermuda 2026 · T−21 days · « all briefs
Regime: PRACTICE + OCEAN-TRACKING — T−21 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 2018 (W-LA/W-RC/W-PL, score 2.55).
- Winner that year: Grundoon (Columbia 50) — 112h corrected (extreme light-air distortion)
- What won: Find Stream core in light air; exploit current as equalizer; don't thrash in the park
- Winning tactics: T-CF T-PF T-CL
- Lesson: Light-air collapses corridor differences but never reverses them. Current core matters more than position.
- Best corridor that year: RHUMB
Per-period classification (current window)
Start anchor: 2026-05-29T00:00:00+00:00 · horizon +167 h
| period | code | conf | GFS wind/gust | ECMWF wind/gust | ICON wind/gust |
|---|---|---|---|---|---|
| P1 start / coastal | W-LA | MEDIUM (67%) | 7.3/16.7 kn | 9.8/17.9 kn | 7.5/16.1 kn |
| P2 Gulf Stream crossing | W-CF /W-SQ (1/3) | HIGH (100%) | 26.1/41.4 kn | 23.9/38.9 kn | 24.6/42.6 kn |
| P3 Bermuda approach | W-PF | MEDIUM (67%) | 16.7/17.3 kn | 14.6/25.7 kn | 15.1/25.7 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 2026-05-28 (T−22):
- Headline analog changed: 2022 → 2018.
- Period codes: P1 W-PF→W-LA.
- Model agreement: 67% ↑ 78%.
- Gulf Stream snapshot unchanged (2026-05-31).
- Crossing SST: 22.1→22.2 °C →, north-wall jump +6.0°C.
- Peak corridor wave: 2.4→2.4 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 | 2018 | 2.55 | W-LA/W-RC/W-PL | RHUMB |
| 2 | 2022 | 0.85 | W-PF/W-CC/W-BH | EAST |
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 geometry — no analyzed Stream snapshot on/before 2026-05-29 yet; the walls + eddy fill in once a snapshot is analyzed.
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 | 13.8 °C / 57 °F | 0.3 kn @ 160° | 1.0 m / 7 s |
| shelf | 16.2 °C / 61 °F | 0.2 kn @ 114° | 1.3 m / 7 s |
| stream | 22.2 °C / 72 °F | 0.7 kn @ 308° | 1.8 m / 7 s |
| post_stream | 22.1 °C / 72 °F | 0.4 kn @ 247° | 2.0 m / 7 s |
| approach | 23.1 °C / 74 °F | 0.8 kn @ 164° | 2.4 m / 7 s |
North wall: SST jumps +6.0 °C from the shelf (16.2 °C) to the crossing (22.2 °C) — a clear Gulf Stream front signature.
Sea state: peak corridor wave ~2.4 m.
Wind-against-current — expect steep, short seas: stream (15.0 kn wind vs 0.7 kn current, 22° apart). Opposed flow stacks the wave train; ease into it and protect the crew/boat. (Coarse model current — confirm against Stream imagery; the real Gulf Stream is stronger, so true wind-against-Stream seas can be worse than this flags.)
Race-day horizon
Race day is T−21 — 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.