Weather Analog Framework - Newport to Bermuda Race

Rev: v2.0 · Updated: 2026-05-29

The W-* taxonomy: 11 recognizable Newport-Bermuda weather patterns. Classify a forecast, find the past races that resemble it, see what routing worked. This is the controlled vocabulary the Forecast → Analog Matcher scores against; the W-* anchors here are its deep-link targets.

TL;DR

Each race year and forecast gets one PRIMARY code, optionally one SECONDARY (use two when a race transitions between patterns).
Profiles cluster into three problems: synoptic/wind (W-BH, W-PF, W-CF, W-LA), Gulf Stream current (W-RC, W-AC, W-CC, W-WE), and light-air shutdown (W-SQ convection, W-BS, W-PL).
The taxonomy is the starting point. Pair it with live current data and the Stream Corridor Decision before committing.

All synoptic ranges and thresholds below (CAPE J/kg, wind kt, current kt, nm, hours, latitude) are DERIVED heuristics — pattern descriptors hand-encoded from the 6-race set (2012–2024), not measured cutoffs or model output.

Analog Type Profiles

W-BH - Stable Bermuda High / Reaching Race

Synoptic: High centered 28–32°N, 60–68°W; ridge extends NW toward US East Coast; no frontal system reaching the fleet; SW–WSW gradient 10–20 kts along the rhumb.

Conditions: Consistent reaching or broad-reaching race; Gulf Stream crossing typically benign; post-Stream either a nice fetch to Bermuda or brief light patch near the island.

Who wins: Boats fast at TWA 70–110° in 12–20 kts. Route differentiation small; Gulf Stream current feature often decisive.

Tactic tags: T-RH, T-PF, T-CF (if CCR available), T-RR
Historical years: 2024 (after frontal clearance), 2012 (W-PF/W-BH reaching), 2022 (partial W-BH after front)
Risk for Lupo: LOW if polar is strong at reaching angles.

W-PF - Pre-Frontal Southerly / Post-Frontal Northerly Transition

Synoptic: Cold front crosses the fleet (typically first 24–48h or during Stream crossing); pre-frontal S–SW; post-frontal NW–W, possibly 20–30+ kts; front passage = 60–90°+ wind rotation in 2–4h.

Conditions: Fleet splits on either side of the front; boats correctly positioned gain hours; Stream crossing with NW post-front can be fast (broad reaching/running).

Who wins: The boat that timed front passage and was positioned on the favorable side.

Tactic tags: T-FR, T-PF, T-WR or T-ER
Historical years: 2022 (W-PF/W-SQ), 2024 (W-PF/W-BH), 2012 (W-PF/W-BH), 2016 (W-PF/W-CC)
Risk for Lupo: HIGH — front timing requires confident forecast and early commitment. If front timing slips 12h, route can look completely wrong. Have pre-front checklist ready (reef #1, kite down, crew briefed) before arrival.

W-LA - Light Air Start with Offshore Compression

Synoptic: High pressure dominating coastal zone at start; <8 kts first 12–24h; gradients develop offshore south of the Nantucket ridge.

Conditions: Slow start; boats bunch; Code Zero / A1 dominant; find the pressure lines — don't park in a hole.

Who wins: Lightweight slippery boats; navigators who correctly identify where gradient builds first.

Tactic tags: T-LA, T-PF
Historical years: 2018 (W-LA/W-PL — current exploitation decisive), 2014
Risk for Lupo: MEDIUM-HIGH if Lupo is not light-air optimized. Verify polar at 6–8 kts. Accept performance deficit; plan around it.

W-CF - Strong Cold Front Crossing Fleet

Synoptic: Active strong cold front; pre-frontal S–SW 20–30+ kts + squalls; frontal passage: thunderstorms, gusts to 40+ kts; post-frontal NW 25–35 kts for 12–24h.

Conditions: Gear damage; potential retirements; boats near the Stream when the front hits face dangerous steep seas.

Who wins: Boats that got far enough south pre-front to ride the NW; heavy-weather capability essential.

Tactic tags: T-WR or T-ER to escape worst; T-FR for positioning
Historical years: None confirmed in 2012–2024 at W-CF intensity. Check pre-2012 records.
Risk for Lupo: VERY HIGH if caught in the Stream during frontal passage. Decision to push south pre-front or slow down must be made at T-24 at latest. W-CF = dominant tactical problem; everything else secondary.

W-SQ - Gulf Stream Squall and Convection Risk

Synoptic: Warm moist air mass over Stream; elevated CAPE (>500 J/kg); high SSTs as convective trigger; may occur within W-BH pattern.

Conditions: Generally benign with embedded convective cells; squalls spike 30–40+ kts for 15–30 min with little warning; lightning possible.

Who wins: Boats that manage squall risk well — reef early, kite down in advance.

Tactic tags: T-RH, T-CL — no route change; conditions management, not routing
Historical years: 2022 (W-PF/W-SQ)
Risk for Lupo: MEDIUM — manageable with squall protocol. See Card 09.

W-RC - Rhumb-Line Favored Current Pattern

Synoptic: North wall near climatological position (~37.5–38.5°N); no significant CCR or WCE; current on rhumb 2.5–4.0 kts favorable.

Conditions: Boats near rhumb have good current and wind; no strong argument to go east or west; often pairs with W-BH.

Who wins: Fastest boat on the rhumb or best combination of pressure + current near rhumb.

Tactic tags: T-RH, T-NW
Historical years: 2024 (southerly meander; up to 5 kts — NOT a CCR; exit timing critical), 2018 (up to 5 kts in light-air year), 2012 (benign Stream)
2024 meander vs CCR distinction: Meanders are more position-reliable than CCRs (connected to main Stream), but require a pre-planned exit — overstaying → east of rhumb → upwind final miles.
Risk for Lupo: LOW. If meander present: SST + RTOFS confirm, enter favorable limb, pre-calculate exit latitude.

W-AC - Adverse Stream Crossing Requiring Detour

Synoptic: Stream current strongly adverse on rhumb (3–5 kts northerly set perpendicular to course) or Stream shifted significantly south.

Conditions: Boats bashing into adverse Stream on rhumb lose 6–12+ hours; west or east detour may be faster despite extra distance.

Who wins: The boat that correctly identified the adverse lane and routed around it.

Tactic tags: T-WR or T-ER for favorable lane; T-CF or T-EC to exploit it
Historical years: None confirmed as pure W-AC in 2012–2024 database.
Risk for Lupo: HIGH if rhumb is taken without checking the current. Classic "didn't look at the Stream" error.

W-CC - Cold Core Ring Opportunity

Synoptic: Actively spinning CCR positioned with western limb within 40–60 nm of rhumb crossing; SST and altimetry both confirm; RTOFS shows circulation.

Conditions: CCR exploit can deliver 1.5–3.0 kts additional current for 50–100 nm → 6–14h advantage. Risk: if ring not where predicted, extra distance kills you.

Who wins: The navigator who confirmed ring position with multiple data sources.

Tactic tags: T-CCR, T-CF, T-EC
Historical years: 2016 (W-CC cautionary tale — CCR present but RTOFS wrong 20–40 nm; boats that committed to CCR detour lost), 2022 (partial CCR; partial benefit for correctly identified boats)
Risk for Lupo: MEDIUM-HIGH. Do NOT commit without SST + altimetry confirmation.

W-WE - Warm Core Eddy Trap

Synoptic: WCE with adverse limb across post-Stream lane ~31–34°N; boats heading south on rhumb run into 1.5–3 kts adverse (westward) current.

Conditions: Boats that don't account for eddy lose 4–10h in final 150–250 nm; WCE often underweighted in routing software.

Tactic tags: T-WCE
Historical years: Not confirmed as dominant factor in 2012–2024; WCE is secondary feature in many years.
Risk for Lupo: MEDIUM — check post-Stream segment in every routing run.

W-BS - Late-Race Bermuda Approach Shutdown

Synoptic: Developing ridge near Bermuda (28–32°N); light air south of ~33°N in final 200 nm.

Conditions: Boats arriving at the "park" early lose all lead; Bermuda sea breeze can provide final-miles pressure if timed.

Tactic tags: T-PF (toward pressure), T-ER or T-WR to avoid park
Historical years: Not confirmed as primary in 2012–2024. Distinct from W-PL (which extends from Stream to Bermuda).
Risk for Lupo: MEDIUM — not catastrophic unless extreme; manageable with good forecast.

W-PL - High Pressure Parking Lot (South of Stream)

Synoptic: Bermuda High expanded south; wide light-air zone 31–35°N after Stream crossing.

Conditions: Fast race to the Stream then slow crawl; elapsed time greatly extended; light-air performance decisive.

Tactic tags: T-PF, T-LA, T-CL (reduce maneuver count in drifting)
Historical years: 2018 (W-LA/W-PL — parking lot; current exploitation decisive because wind so light)
Risk for Lupo: MEDIUM-HIGH if not a light-air specialist. Accept the conditions; do not burn crew chasing fractions.

Historical Year Classification

Year	Primary	Secondary	Gulf Stream	Key Tactic That Won	Winner
2024	W-PF	W-BH, W-RC	Up to 5 kts; southerly meander (NOT CCR)	Avoid frontal patch + ride meander, pre-plan exit	Carina (Rives Potts)
2022	W-PF	W-SQ	Chaotic CCR (oxbow); Illusion held eddy 7h	Post-frontal NW + 7h eddy hold	Illusion (Cal 40, Stan Honey)
2018	W-LA	W-PL	Up to 5 kts favorable; parking lot south	Find Stream core; exploit current; don't thrash in park	Grundoon (Columbia 50)
2016	W-PF	W-CC	CCR near rhumb — RTOFS WRONG	Stay near rhumb; don't trust RTOFS alone	Warrior Won (Xp44)
2014	W-LA	W-PF, W-RC	Up to 5 kts favorable	Conservative west; exploit Stream; exit at right latitude	Actaea (Hinckley B40 yawl)
2012	W-PF	W-BH	Normal — benign, not a differentiator	Simple execution near rhumb; low maneuver count	Carina (corrected)

Three-year strong-current pattern (2014, 2018, 2024): Light-air years consistently delivered up to 5 kts Gulf Stream favorable current. In W-LA analog, the Stream is the primary race differentiator.

The consistent loser's trait: Complicated detours based on single-model current prediction, or excessive maneuver count without compensating gain.

Analog Matching Procedure

This is the manual version of what the matcher does per period (P1 start, P2 Stream, P3 approach):

Classify the synoptic setup at each of the three race times — start +12h (coastal), +36–48h (Stream), +60–80h (post-Stream to Bermuda) — with its best-matching W-* code.
Pull the 2–3 closest historical years. For each: winner's route, result for boats like Lupo, how closely the forecast matches, and what would make the analog fail.
Assign confidence: HIGH (all 3 periods match; models agree) / MEDIUM (2 of 3, or models diverge) / LOW (1 period, or unusual pattern).
Document it — or let the matcher score it automatically.

Sources

Taxonomy & per-year encoding — hand-curated from the 6-race set (2012, 2014, 2016, 2018, 2022, 2024); consumed by scripts/analysis/analog_matcher.py (the YEARS dict mirrors this table).
Winner routes & tactics — winner_route_summary.md, Routing Tactic Catalog (T-* codes).
Gulf Stream features (CCR / WCE / RTOFS) — gulf_stream_framework.md.
Live classification & matching — forecast_analog_matcher.md, scripts/daily_brief.py.

PRE-RACE RESEARCH — not race-period routing advice. Updated 2026-05-29.