Catherine's Tropical Cyclone Watch

🚨 Anegada Passage east of Virgin Gorda and Saint Croix south to 17N: Marine Weather Statement issued November 6 at 1:27PM AST by NWS San Juan PR 🚨 Southwest Phillips: High Wind Warning issued November 6 at 10:25AM MST until November 7 at 9:00AM MST by NWS Glasgow MT 🚨 Central and Southeast Phillips; Central and Southern Valley; Petroleum; Garfield; McCone: Lake Wind Advisory issued November 6 at 10:25AM MST until November 7 at 4:00PM MST by NWS Glasgow MT 🚨 Waters from Point Reyes to Pigeon Point 10-60 NM: Small Craft Advisory issued November 6 at 9:25AM PST until November 8 at 9:00PM PST by NWS San Francisco CA 🚨 Waters from Pigeon Point to Point Pinos 10-60 NM: Small Craft Advisory issued November 6 at 9:25AM PST until November 8 at 9:00PM PST by NWS San Francisco CA 🚨 Waters from Point Pinos to Point Piedras Blancas 10-60 NM: Small Craft Advisory issued November 6 at 9:25AM PST until November 8 at 9:00PM PST by NWS San Francisco CA 🚨 Coastal Waters from Pigeon Point to Point Pinos California out to 10 nm: Small Craft Advisory issued November 6 at 9:25AM PST until November 8 at 9:00PM PST by NWS San Francisco CA 🚨 Coastal Waters from Point Pinos to Point Piedras Blancas California out to 10 nm: Small Craft Advisory issued November 6 at 9:25AM PST until November 8 at 9:00PM PST by NWS San Francisco CA 🚨 Waters from Point Arena to Point Reyes 10-60 NM: Small Craft Advisory issued November 6 at 9:25AM PST until November 8 at 9:00PM PST by NWS San Francisco CA 🚨 Montgomery: None

Active Tropical Systems & Formation Outlook

A whole-basin summary of all active tropical cyclones and the NHC Tropical Weather Outlook, generated with the tropycal package. Select a storm below for its official forecast and model guidance.

Summary & NHC 7-Day Formation Outlook

Valid: 17 UTC 06 Nov 2026

Select a Storm

94L (AL942026)

Type: EX Max Wind: 35 kt Min Pressure: 1003 hPa Position: 24.7, -65.2 Basin: North Atlantic

2-Day Formation: 10% (Low) 5-Day Formation: N/A (N/A)

95C (CP952026)

Type: DB Max Wind: 30 kt Min Pressure: 1007 hPa Position: 11.0, -148.6 Basin: East Pacific

THIRTYONE (WP312026)

Type: TD Max Wind: 30 kt Min Pressure: 1006 hPa Position: 17.9, 147.5 Basin: West Pacific

HAFS and GEFS guidance is only available for storms in the US/NHC domain (Atlantic & East/Central Pacific). For this system, the basin summary and best-track position are shown.

WDPN31 PGTW 061500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 31W (THIRTYONE) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.9N 147.5E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 293 NM NORTH-NORTHEAST OF ANDERSEN AFB MOVEMENT PAST 6 HOURS: WESTWARD AT 14 KTS SIGNIFICANT WAVE HEIGHT: 13 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED SHORTWAVE INFRARED (SWIR) SATELLITE IMAGERY DEPICTS A VERTICALLY TILTED, ASYMMETRIC SYSTEM, WITH THE MID-LEVEL VORTEX DISPLACED WESTWARD (DOWNSHEAR) OF A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). A 061113Z ASCAT PARTIAL PASS REVEALED A COMPACT LLCC ON THE EDGE OF THE OBSERVATIONAL SWATH, WITH WINDS OF 25-30 KNOTS ON THE NORTHERN FLANK OF THE LLCC, 20-KNOT WINDS BEGINNING TO WRAP AROUND THE WESTERN SEMICIRCLE, AND LIGHTER WINDS ON THE SOUTHERN FLANK. A 061059Z GMI COLOR-ENHANCED 89 GHZ MICROWAVE IMAGE DEPICTED SHALLOW CONVECTIVE BANDING FEATURES WRAPPING INTO A WELL-DEFINED, BUT EXPOSED LLCC LOCATED TO THE EAST OF AN AREA OF DISORGANIZED DEEP CONVECTION, WHICH REMAINS UNABLE TO WRAP UPSHEAR DUE TO MODERATE EASTERLY VERTICAL WIND SHEAR (VWS). UPPER-LEVEL ATMOSPHERIC MOTION VECTORS (AMVS) DEPICT DEEP, STRONG EASTERLY FLOW DIRECTLY OVERLYING TD 31W, THOUGH INITIAL SIGNS OF DIFLUENCE AND A SPLIT IN THE UPSTREAM FLOW PATTERN ARE BEGINNING TO EMERGE IN THE AMV DATA. THE 061200Z UPPER-AIR SOUNDING FROM PGUM INDICATES DEEP EASTERLIES EXTENDING UP TO APPROXIMATELY 400 MB, BEFORE VEERING SHARPLY TO SOUTHWESTERLIES BETWEEN 400 MB AND 350 MB AND RESUMING EASTERLY FLOW ABOVE THAT LAYER, HIGHLIGHTING THE PRIMARY MECHANISM DRIVING THE ENHANCED MID-LEVEL SHEAR. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE WELL-DEFINED LLCC IN THE SWIR IMAGERY AND THE ASCAT DATA. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE ASCAT DATA, CONFIRMING THE OBJECTIVE INTENSITY ESTIMATES OUTLINED BELOW. ENVIRONMENTAL CONDITIONS ARE GENERALLY FAVORABLE, CHARACTERIZED BY LOW TO MODERATE DEEP-LAYER SHEAR, HIGH SEA SURFACE TEMPERATURES (SSTS), AND STRONG DIVERGENT OUTFLOW ALOFT, THOUGH TEMPERED BY THE VERTICALLY DECOUPLED VORTEX. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS RJTD: T1.5 - 25 KTS CIMSS ADT: 28 KTS AT 061130Z CIMSS AIDT: 33 KTS AT 061130Z CIMSS D-MINT: 30 KTS AT 061102Z CIMSS D-PRINT: 30 KTS AT 061130Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: OVER THE PAST SIX HOURS, TROPICAL DEPRESSION (TD) 31W HAS TRANSITIONED TO A DUE WESTWARD TRAJECTORY, STEERED BY THE MORE ZONALLY ORIENTED LOWER-LEVEL FLOW AXIS OF THE STR TO THE NORTHEAST DUE TO SHALLOW VORTEX DEPTH. GLOBAL MODELS AGREE THAT OVER THE NEXT 6-12 HOURS, THE RIDGE AXIS WILL AMPLIFY INTO A MORE NORTHWEST-SOUTHEAST ORIENTATION, ALLOWING TD 31W TO RESUME A NORTHWESTWARD TRAJECTORY; HOWEVER, A MORE ZONAL WESTWARD NEAR-TERM TRAJECTORY REMAINS POSSIBLE IF THE VORTEX REMAINS DECOUPLED. TRANSLATIONAL SPEEDS ARE FORECAST TO REMAIN RELATIVELY STABLE THROUGH TAU 24 BEFORE GRADUALLY DECELERATING AS THE STR CENTER PROPAGATES EASTWARD AND THE STEERING GRADIENT RELAXES. AFTER TAU 36, THE PASSAGE OF A MID-LATITUDE SHORTWAVE TROUGH TO THE NORTH WILL BEGIN TO ERODE THE RIDGE, WITH A…

94S (SH942027)

Type: TD Max Wind: 25 kt Min Pressure: 1007 hPa Position: -13.6, 55.9 Basin: South Indian

HAFS and GEFS guidance is only available for storms in the US/NHC domain (Atlantic & East/Central Pacific). For this system, the basin summary and best-track position are shown.

ECMWF 10-m Streamlines

This map visualizes near-surface winds from the ECMWF operational model using streamlines — continuous curves that show the direction of the wind at every point. Streamlines help us visually detect patterns of atmospheric flow, such as jets, troughs, and areas of rotation.

Forecasters at the NHC monitor 10-meter wind fields for signs of a closed low-level circulation — a common feature of early tropical cyclone formation. When streamlines wrap into a tight, circular pattern and form a closed loop, it may signal that a system is transitioning from a disorganized disturbance into a structured cyclone.

This early organization of wind flow is a key threshold in classifying an area as a potential tropical cyclone. While other ingredients like convection and mid-level humidity are also necessary, closed low-level circulation is often the first structural milestone forecasters look for.

Look for small, circular loops in the streamlines over oceanic regions — especially where other environmental factors also align for storm formation.

ECMWF Predictions

No active storm found in ECMWF data at this time.

Environmental Indicators

Hypothetical TC Drift Paths

This map displays hypothetical tropical cyclone (TC) paths projected from genesis-favorable zones identified by an environmental mask. These paths are computed using the Emanuel Beta and Advection Model, a physically based framework that estimates the motion of nascent cyclones by combining steering-level winds and planetary rotation effects.

The model blends winds from two critical pressure levels — 850 hPa (lower troposphere) and 250 hPa (upper troposphere) — weighted toward the lower level where most of a tropical cyclone's mass resides. It also incorporates a background component associated with beta drift, which arises from the variation of the Coriolis force with latitude.

Each pink trajectory represents a storm initialized from a grid cell where all five environmental thresholds were favorable: high CAPE, low vertical wind shear, high mid-level humidity, warm SSTs, and positive low-level vorticity. Arrows darken with time, tracing the cyclone’s evolution in 6-hour steps. These tracks can move over land given the steering winds, but in reality these storms weaken quickly when no longer over warm water. This means the tracks that move over significant would likely die out quickly and are not well represented in this model.

Hypothetical storms often drift westward and poleward, steered by large-scale tropical flow and Earth's rotation — this helps forecasters anticipate where early-stage disturbances might evolve into organized storms.

Pressure & Rainfall (hPa)

This chart shows 24-hour forecasts of surface pressure (in hPa) and precipitation (in mm) for select U.S. cities. The data comes from the Open-Meteo API, which sources its predictions from high-resolution numerical weather models like ICON (from the German Weather Service) and ECMWF's IFS. These are advanced general circulation models (GCMs) that solve physical equations governing the atmosphere — including thermodynamics, fluid motion, and radiation — to simulate and forecast future states of weather.

A sudden drop in pressure may signal the approach of a developing storm system. Increasing rainfall intensity often tracks with tropical activity or frontal systems. These paired indicators help visualize evolving atmospheric instability and potential hazards.

NBDC Gulf Buoy Data

This data comes from the National Data Buoy Center (NDBC), a division of NOAA responsible for monitoring ocean and atmospheric conditions using moored buoys, coastal stations, and drifting floats. These sensors play a vital role in tracking tropical cyclone development by recording variables like wind speed, barometric pressure, air & sea surface temperatures, and wave height — all of which help determine storm structure and intensification.

A sudden drop in sea-level pressure or a spike in wind gusts can signal rapid cyclone strengthening. Water temperature above ~26°C is a key fuel source for tropical cyclones. Wave and swell height give insight into the storm’s reach and energy transfer across the ocean. Monitoring these in real time helps improve forecasts and early warnings.

Wind: NNE (30°), 9.7 kt | Gust: 11.7 kt

Pressure: 29.97 steady | Air Temp: 79.0 °F

Water Temp: 81.1 °F | Dew Point: 76.3 °F

Swell: 0.0 ft | Wind Wave: 1.0 ft

NWS U.S. Radar

The National Weather Service (NWS) collects radar data using the NEXRAD (Next Generation Radar) network — a nationwide system of over 150 high-resolution Doppler radar stations. Radar works by emitting pulses of energy that bounce off precipitation (like raindrops, hail, or snow) and return to the radar dish. Doppler radar not only detects the location and intensity of storms, but also their motion — by measuring shifts in frequency caused by movement of particles toward or away from the radar site. This allows meteorologists to spot rotating storms and potential tornadoes in real time.

GOES 15-min Satellite

The GOES (Geostationary Operational Environmental Satellite) system is operated by NOAA and provides continuous weather observation over the Americas. Orbiting 22,300 miles above Earth, GOES satellites deliver high-resolution imagery every 15 minutes, helping track tropical systems, cloud formation, and atmospheric motion in real time. The Geocolor imagery shown here combines visible and infrared data to highlight clouds, land, and sea in a natural-looking format.

GOES Band 13 – Infrared (IR) Imagery

Band 13 (10.3 µm) is one of the most important infrared channels for tropical meteorology, measuring emitted radiation from cloud tops. Colder colors (red, yellow) signal deep convection, where strong thunderstorms punch through the upper atmosphere. These features often indicate the early stages of tropical cyclone formation.

Most recent GOES Band 13 image. Provided by NOAA/NESDIS/STAR.

CJ · TC