🚨 Lagrange; Steuben; Noble; De Kalb: Special Weather Statement issued November 9 at 6:28AM EST by NWS Northern Indiana 🚨 La Salle; McMullen; Duval: Special Weather Statement issued November 9 at 5:25AM CST by NWS Corpus Christi TX 🚨 Montgomery: None 🚨 Tidal Potomac from Cobb Island MD to Smith Point VA: Small Craft Advisory issued November 9 at 6:18AM EST until November 10 at 12:00AM EST by NWS Baltimore MD/Washington DC 🚨 Tidal Potomac from Key Bridge to Indian Head MD; Tidal Potomac from Indian Head to Cobb Island MD: Small Craft Advisory issued November 9 at 6:18AM EST until November 9 at 6:00PM EST by NWS Baltimore MD/Washington DC 🚨 Chesapeake Bay north of Pooles Island MD; Chesapeake Bay from Pooles Island to Sandy Point MD; Chesapeake Bay from Sandy Point to North Beach MD; Chesapeake Bay from North Beach to Drum Point MD; Chesapeake Bay from Drum Point MD to Smith Point VA; Patapsco River including Baltimore Harbor; Chester River to Queenstown MD; Eastern Bay; Choptank River to Cambridge MD and the Little Choptank River; Patuxent River to Broomes Island MD; Tangier Sound and the inland waters surrounding Bloodsworth Island: Small Craft Advisory issued November 9 at 6:18AM EST until November 10 at 12:00AM EST by NWS Baltimore MD/Washington DC 🚨 Inland Volusia; Northern Lake County; Southern Lake County: Special Weather Statement issued November 9 at 6:17AM EST by NWS Melbourne FL 🚨 Tattnall; Evans; Long; Inland Liberty; Coastal Liberty; Inland McIntosh; Coastal McIntosh: Special Weather Statement issued November 9 at 6:10AM EST by NWS Charleston SC 🚨 Inland Jefferson; Madison; Inland Taylor; Lafayette; Inland Dixie; Coastal Jefferson; Coastal Taylor; Coastal Dixie; Brooks; Lowndes; Lanier: Dense Fog Advisory issued November 9 at 6:08AM EST until November 9 at 9:00AM EST by NWS Tallahassee FL 🚨 Alexander; Iredell; Davie; Catawba; Rowan; Cleveland; Lincoln; Greater Caldwell; Greater Burke; Eastern McDowell; Greater Rutherford: Frost Advisory issued November 9 at 5:57AM EST until November 9 at 9:00AM EST by NWS Greenville-Spartanburg SC
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.
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 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 31W (CEMPAKA) WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 24.0N 134.9E
INITIAL INTENSITY: 85 KTS
GEOGRAPHIC REFERENCE: 353 NM WEST OF IWO TO
MOVEMENT PAST 6 HOURS: NORTHWARD AT 02 KTS
SIGNIFICANT WAVE HEIGHT: 30 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON 31W
(CEMPAKA) WITH A SIGNIFICANTLY IMPROVED STRUCTURE OVER THE PAST 6
HOURS, MADE APPARENT BY THE DEVELOPMENT OF A 15 NM EYE THAT IS
CONTINUING TO CLEAR OUT. THE CENTRAL DENSE OVERCAST (CDO) IS ALSO
BECOMING MORE UNIFORM AROUND THE CENTER. THE BULK OF THE STRONGEST
CONVECTIVE ACTIVITY IS LOCATED WITHIN THE NORTHERN SEMICIRCLE OF
THE EYEWALL, WHICH ALSO CORRESPONDS TO THE LOCATION OF THE
STRONGEST WINDS. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EYE IN ANIMATED MSI. THE INITIAL INTENSITY
OF 85 KTS IS ASSESSED WITH LOW CONFIDENCE BASED PRIMARILY ON THE
HIGH END OF THE T4.5 AGENCY DVORAK FIXES FROM PGTW AND RCTP. THE
VARIOUS CIMSS INTENSITY ESTIMATES ARE CONSIDERABLY TOO LOW FOR THE
SYSTEM CONSIDERING THE CURRENT STRUCTURE. ENVIRONMENTAL ANALYSIS
INDICATES THAT 31W IS NOW IN A MARGINALLY FAVORABLE ENVIRONMENT
WHICH IS MAINLY ATTRIBUTED TO THE DRY AIR ENTRAINMENT FROM THE
NORTH THAT IS ASSOCIATED WITH THE NORTHEASTERLY SURGE. OTHER
ENVIRONMENTAL VARIABLES REMAIN FAVORABLE DUE TO STRONG POLEWARD
OUTFLOW ALOFT, LOW (10-15 KTS) VERTICAL WIND SHEAR, AND WARM (27-28
C) SEA SURFACE TEMPERATURES.
INITIAL WIND RADII BASIS: PERSISTENCE WITH SLIGHT ADJUSTMENTS MADE
BASED ON THE OBJECTIVE BEST TRACK
CURRENT STEERING MECHANISM: COMPETING STEERING PATTERN WITH RIDGING
TO BOTH THE EAST AND WEST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.5 - 77 KTS
RJTD: T4.0 - 65 KTS
RCTP: T4.5 - 77 KTS
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 10-15 KTS
SST: 27-28 CELSIUS
OUTFLOW: STRONG POLEWARD
OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE NORTH
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: LOW
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: TRACK SPEEDS HAVE BEEN INCREASED
FOLLOWING TAU 24 COMPARED TO THE PREVIOUS FORECAST
FORECAST DISCUSSION: TY 31W IS FORECAST TO IMMINENTLY START
ACCELERATING EAST-NORTHEASTWARD AS AN INCOMING MID-LATITUDE TROUGH
DIGS IN FROM THE NORTH AND A NEAR-EQUATORIAL RIDGE (NER) BUILDS TO
THE SOUTH. THE EAST-NORTHEASTWARD TRAJECTORY IS THEN EXPECTED TO
PERSIST THROUGH TAU 48 UNDER THE COMBINED STEERING INFLUENCE OF THE
TWO AFOREMENTIONED SYNOPTIC FEATURES. NEAR TAU 48, 31W WILL BEGIN
TO INTERACT WITH A FRONTAL BOUNDARY CONNECTED TO A LARGE LOW
PRESSURE SYSTEM LOCATED NEAR THE ALEUTIAN ISLANDS. THE SYSTEM IS
THEN FORECAST TO TRACK GENERALLY EASTWARD THROUGH TAU 72 AS IT
MERGES WITH THE BOUNDARY. THIS FORECAST SHOWS A FASTER MOVEMENT TO
THE EAST COMPARED TO THE PREVIOUS FORECAST DUE TO MODELS BECOMING
MORE ALIGNED ON EXTENDED INTERACTION WITH THE MID-LATITUDE TROUGH
RATHER THAN IT LEAVING 31W BEHIND TO DRIFT EQUATORWARD. IN TERMS OF
INTENSITY, 31W IS FORECAST TO CONTINUE INTENSIFYING FOR ONLY
ANOTHER 12 HOURS BEFORE WESTERLY SHEAR AND DRY AIR BECOME
SIGNIFICANT. A MORE GRADUAL WEAKENING TREND IS FORECAST FROM TAU 12
TO TAU 24 AS THE SHEAR REMAINS MODERATE. HOWEVER, SHEAR WILL
INCREASE FURTHER TO OVER 30 KTS AT TAU 36 AND 50 KTS AT TAU 60,
WHICH WILL CAUSE A MORE RAPID WEAKENING TREND THROUGH THE REMAINDER
OF THE FORECAST PERIOD. AT TAU 72, 31W IS FORECAST TO BE FULLY
EMBEDDED WITHIN THE FRONTAL BOUNDARY WITH AN EXTREMELY ELONGATED
WIND FIELD. AS A RESULT, THE SYSTEM IS LABELED TO BE DISSIPATED
OVER WATER EVEN THOUGH THE INTENSITY REMAINS AT 40 KTS. THE
INTENSITY AT THE END OF THE FORECAST P…
THREE
(SH032027)
Type: TDMax Wind: 25 ktMin Pressure: 1012 hPaPosition: -10.9, 48.9Basin: 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: NE (50°), 7.8 kt | Gust: 11.7 kt
Pressure: 30.05 steady | Air Temp: 74.5 °F
Water Temp: 81.3 °F | Dew Point: 64.6 °F
Swell: 1.3 ft | Wind Wave: 1.3 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.