🚨 Lincoln; Lyon; Murray; Pipestone; Rock; Kingsbury; Brookings; Miner; Lake; Moody; Hanson; McCook; Minnehaha; Hutchinson; Turner; Lincoln: Special Weather Statement issued July 4 at 6:30AM CDT by NWS Sioux Falls SD 🚨 Atchison; Miami; Linn; Leavenworth; Wyandotte; Johnson; Platte; Clay; Ray; Carroll; Chariton; Randolph; Jackson; Lafayette; Saline; Howard; Cass; Johnson; Pettis; Cooper; Bates; Henry: Extreme Heat Warning issued July 4 at 6:27AM CDT until July 4 at 8:00PM CDT by NWS Kansas City/Pleasant Hill MO 🚨 Doniphan; Atchison; Nodaway; Worth; Gentry; Harrison; Mercer; Putnam; Schuyler; Holt; Andrew; De Kalb; Daviess; Grundy; Sullivan; Adair; Buchanan; Clinton; Caldwell; Livingston; Linn; Macon: Heat Advisory issued July 4 at 6:27AM CDT until July 4 at 8:00PM CDT by NWS Kansas City/Pleasant Hill MO 🚨 Montgomery: None 🚨 Admiralty Inlet: Small Craft Advisory issued July 4 at 4:24AM PDT until July 5 at 3:00AM PDT by NWS Seattle WA 🚨 Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm; Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm: Small Craft Advisory issued July 4 at 4:24AM PDT until July 5 at 9:00AM PDT by NWS Seattle WA 🚨 Central U.S. Waters Strait Of Juan De Fuca; East Entrance U.S. Waters Strait Of Juan De Fuca: Small Craft Advisory issued July 4 at 4:24AM PDT until July 5 at 3:00AM PDT by NWS Seattle WA 🚨 Clay, KY; Knox, KY; Laurel, KY: Flood Advisory issued July 4 at 7:23AM EDT until July 4 at 9:15AM EDT by NWS Jackson KY 🚨 Texas; Dallam; Sherman; Hansford; Ochiltree; Hartley; Moore; Hutchinson; Roberts; Oldham; Potter; Deaf Smith; Randall; Palo Duro Canyon: Heat Advisory issued July 4 at 6:22AM CDT until July 4 at 8:00PM CDT by NWS Amarillo TX 🚨 Boone, IA; Jasper, IA; Marshall, IA; Polk, IA; Story, IA: Flood Warning issued July 4 at 6:21AM CDT until July 4 at 6:15PM CDT by NWS Des Moines IA
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 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (BAVI) WARNING NR
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 12.5N 150.8E
INITIAL INTENSITY: 145 KTS
GEOGRAPHIC REFERENCE: 352 NM EAST OF ANDERSEN AFB
MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
SIGNIFICANT WAVE HEIGHT: 50 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN
IMPROVEMENT IN THE CONVECTIVE STRUCTURE OF SUPER TYPHOON 09W. THE
CANOPY OF THE CENTRAL DENSE OVERCAST HAS BECOME MORE SYMMETRICAL
AND SMOOTHER, AND CLOUD TOP TEMPERATURES HAVE TRENDED COOLER. THE
EYE HAS CLEARED OUT, AND THE UPPER-LEVEL OUTFLOW HAS EXPANDED.
THESE INDICATORS POINT TO CONTINUED INTENSIFICATION. A 040252Z
AMSR-2 PASS SHOWS A VERY STRONG INNER CORE WITH A RING OF WEAKER
CONVECTION SURROUNDING THE EYEWALL. WHILE IT IS INCONCLUSIVE THAT
AN EYEWALL REPLACEMENT CYCLE (ERC) HAS BEGUN, THE CIMSS MPERC
ALGORITHM HAS LATCHED ON, ESTIMATING A 64 PERCENT PROBABILITY OF
ERC ONSET. THE ENVIRONMENT IS HIGHLY SUPPORTIVE OF A HIGH-END
STORM, CHARACTERIZED BY LOW VERTICAL WIND SHEAR, HIGH OCEAN HEAT
CONTENT (OHC) APPROACHING 150 KJ PER SQUARE CM, AND ABUNDANT
DEEP-LAYER MOISTURE. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE CLEAR EYE MEASURING 18 NM IN DIAMETER. THE
INITIAL INTENSITY WAS RAISED TO 145 KTS WITH MEDIUM CONFIDENCE
BASED ON THE IMPROVED CONVECTIVE SIGNATURE AND IS CLOSE TO THE
UNANIMOUS T7.0 FROM PGTW, KNES, RJTD, AND RCTP AND THE CIMSS
OBJECTIVE ESTIMATES RANGING FROM 140 KTS TO 145 KTS.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: EASTERN EXTENSION OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED EAST OF THE RYUKYU ISLANDS
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T7.0 - 140 KTS
RJTD: T7.0 - 140 KTS
RCTP: T7.0 - 140 KTS
KNES: T7.0 - 140 KTS
CIMSS SATCON: 141 KTS AT 040600Z
CIMSS ADT: 140 KTS AT 040600Z
CIMSS AIDT: 142 KTS AT 040600Z
CIMSS D-MINT: 145 KTS AT 040607Z
CIMSS D-PRINT: 143 KTS AT 040600Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: STY 09W IS PRIMARILY BEING STEERED DUE WEST BY
A DEEP-LAYER STR TO THE NORTH. THIS NEW MOTION REPRESENTS THE END
OF THE WEST-SOUTHWESTWARD MOVEMENT IN THE PAST 24 HOURS. THE
FORECAST CALLS FOR A TURN TOWARDS THE WEST-NORTHWEST AND A FASTER
RATE OF MOTION WITHIN THE NEXT 12-24 HOURS AS THE INFLUENCE OF A
NEAR-EQUATORIAL RIDGE OVER THE SOLOMON ISLANDS DIMINISHES AND A
STRONGER RIDGE BUILDS NORTHEAST OF THE VORTEX. THE MOTION WILL
PERSIST THROUGH THE END OF THE PERIOD. THE AVAILABLE MICROWAVE
IMAGERY AND MPERC SUGGEST THAT ERC WILL COMMENCE IMMINENTLY, IF NOT
ALREADY UNDERWAY. THE ERC WILL LEAD TO WEAKENING DURING THE FIRST
24 HOURS. ONCE ERC COMPLETES, STY BAVI WILL UNDERGO ANOTHER ROUND
OF INTENSIFICATION TO AT LEAST 150 KNOTS AS IT PASSES THE MARIANA
ISLANDS. IT IS CHALLENGING TO FORECAST THE AMOUNT OF WEAKENING DUE
TO ERC AND THE TIMING OF ERC COMPLETION, SO QUITE A BIT OF
UNCERTAINTY IN THE INTENSITY FORECAST EXISTS FOR THE FIRST 48
HOURS. THE ENVIRONMENT WILL REMAIN HIGHLY SUPPORTIVE OF THE EXTREME
INTENSITY. IN FACT, AS THE CIRCULATION APPROACHES THE MARIANA
ISLANDS, AN UPPER-LEVEL RIDGE WILL BUILD JUST SOUTH OF HONSHU AND
SIGNIFICANTLY INCREASE WESTWARD OUTFLOW ALOFT BEGINNING AT TAU 24.
STY BAVI WILL INTENSIFY AS A RESULT OF THE ENHANCED DIVERGENCE
ALOFT IF ERC CAN PROMPTLY COMPLETE. THE STORM WILL GROW VERY LARGE
IN SIZE AS A RESULT O…
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.
WDPN32 PGTW 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MAYSAK) WARNING NR
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 20.6N 107.8E
INITIAL INTENSITY: 45 KTS
GEOGRAPHIC REFERENCE: 109 NM EAST-SOUTHEAST OF HANOI, VIETNAM
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
SIGNIFICANT WAVE HEIGHT: 16 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY
EXPOSED LOWER-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION
WRAPPING INTO THE SOUTHERN AND EASTERN PERIPHERY OF THE VORTEX. THE
VENTILATION ALOFT HAS IMPROVED IN THE PRESENCE OF LOW TO MODERATE
NORTHEASTERLY SHEAR. THE ENVIRONMENT IS GENERALLY FAVORABLE FOR
INTENSIFICATION, CHARACTERIZED BY WARM SEA SURFACE TEMPERATURE
(SST), VERY PLENTIFUL DEEP-LAYER MOISTURE, AND LOW TO MODERATE
VERTICAL WIND SHEAR (VWS). DATA FROM A 040453Z OSCAT-3 PASS REVEALS
THAT THE HIGHEST WINDS ARE CONFINED TO THE EASTERN SIDE OF THE
LLCC, AND THE VORTEX HAS TIGHTENED UP. THE INITIAL POSITION IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE CURVATURE OF THE RAIN
BANDS. THE INITIAL POSITION REMAINS AT 45 KTS WITH MEDIUM
CONFIDENCE BASED ON THE T3.0 DVORAK ESTIMATES FROM PGTW AND RJTD
AND THE AFOREMENTIONED OSCAT-3 PASS.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A MID-LEVEL
SUBTROPICAL RIDGE (STR) CENTERED NEAR THE RYUKYU ISLANDS
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.0 - 45 KTS
RJTD: T3.0 - 45 KTS
RCTP: T2.5 - 35 KTS
KNES: T3.5 - 55 KTS
CIMSS SATCON: 53 KTS AT 040600Z
CIMSS ADT: 57 KTS AT 040600Z
CIMSS AIDT: 53 KTS AT 040600Z
CIMSS D-MINT: 50 KTS AT 040541Z
CIMSS D-PRINT: 36 KTS AT 040600Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 10-15 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE EQUATORWARD
OTHER FACTORS: LAND INTERACTION
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: THE CIRCULATION IS BEING DRIVEN POLEWARD BY A
MID-LEVEL STR TO THE WEST. TROPICAL STORM 10W WILL TURN TOWARDS THE
NORTHEAST AS IT CROSSES THE RIDGE AXIS. LOW TO MODERATE VWS, WARM
SST, AND ABUNDANT DEEP-LAYER MOISTURE POINT TO AN ENVIRONMENT
FAVORABLE FOR DEVELOPMENT. MAYSAK STILL HAS APPROXIMATELY 6 HOURS
REMAINING OVER WATER TO INTENSIFY, SO A PEAK OF 50 KT IS POSSIBLE
PRIOR TO LANDFALL BETWEEN TAU 0 AND TAU 12. ONCE LANDFALL OCCURS,
THE CIRCULATION WILL TRAVERSE OVER RUGGED TERRAIN AND QUICKLY
WEAKEN. THE FORECAST CALLS FOR DISSIPATION TO OCCUR BY TAU 36.
MODEL DISCUSSION: THE AVAILABLE MODEL GUIDANCE AGREES ON A POLEWARD
TRACK UNTIL DISSIPATION. ECMWF AND NAVGEM LIE ON THE WESTERN SIDE
OF THE GUIDANCE ENVELOPE WITH HAFS-A ON THE OTHER END. THE JTWC
FORECAST TRACK IS PLACED NEAR THE CONSENSUS WITH HIGH CONFIDENCE.
THE RELIABLE INTENSITY AIDS ALL DEPICT STEADY TO RAPID WEAKENING
AFTER TAU 12 DUE TO THE FRICTIONAL AND DRYING EFFECTS OF LAND. THE
JTWC FORECAST CALLS FOR STEADY WEAKENING WITH HIGH CONFIDENCE AS
THE TROPICAL STORM INTERACTS WITH LAND.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
INTENSITY 00-72 HR: HIGH//
NNNN
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: SSW (210°), 3.9 kt | Gust: 3.9 kt
Pressure: 30.02 falling | Air Temp: 83.8 °F
Water Temp: 86.4 °F | Dew Point: 77.4 °F
Swell: | Wind Wave:
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.
