🚨 Montgomery: None 🚨 Mesa, CO: Flood Advisory issued August 30 at 6:27PM MDT until August 30 at 9:30PM MDT by NWS Grand Junction CO 🚨 Wayne, UT: Flash Flood Warning issued August 30 at 6:27PM MDT until August 30 at 7:30PM MDT by NWS Salt Lake City UT 🚨 Delta, CO; Mesa, CO: Severe Thunderstorm Warning issued August 30 at 6:26PM MDT until August 30 at 6:45PM MDT by NWS Grand Junction CO 🚨 Coconino, AZ: Flash Flood Warning issued August 30 at 5:25PM MST until August 30 at 10:15PM MST by NWS Flagstaff AZ 🚨 Burleigh, ND; Emmons, ND; Grant, ND; Morton, ND; Oliver, ND; Sioux, ND: Severe Thunderstorm Warning issued August 30 at 7:25PM CDT until August 30 at 7:45PM CDT by NWS Bismarck ND 🚨 Wasatch Plateau/Book Cliffs; Western Uinta Basin: Special Weather Statement issued August 30 at 6:23PM MDT by NWS Salt Lake City UT 🚨 Kane, UT: Flash Flood Warning issued August 30 at 6:20PM MDT until August 30 at 9:30PM MDT by NWS Salt Lake City UT 🚨 La Paz, AZ: Severe Thunderstorm Warning issued August 30 at 5:19PM MST until August 30 at 5:45PM MST by NWS Phoenix AZ 🚨 Kane, UT: Flash Flood Warning issued August 30 at 6:17PM MDT until August 30 at 7:15PM MDT by NWS Salt Lake City UT
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.
ZCZC MIATCDEP1 ALL
TTAA00 KNHC DDHHMM
Hurricane Karina Special Discussion Number 14
NWS National Hurricane Center Miami FL EP112026
500 PM PDT Sun Aug 30 2026
The satellite presentation of Karina has improved immensely over the
past several hours. Very cold cloud top temperatures of -70 to -75 C
now completely surround a warm eye, with temperatures near 0 to -5
C. An earlier GPM GMI microwave pass also revealed a compact and
well-established eye and pronounced curved banding around the
center. Karina is moving over very warm sea surface temperatures
near 29 C and remains in an environment highly conducive to further
intensification. Objective intensity estimates have also increased
rapidly over the past several hours, ranging from 88-109 kt. Based
on the satellite presentation, microwave imagery, environmental
conditions and objective intensity estimates, the initial intensity
is set at 110 kt, making Karina a major hurricane. The intensity
forecast has been increased from the previous advisory.
There were no changes made to the track or wind radii forecasts. A
new forecast will be issued at 0300 UTC.
FORECAST POSITIONS AND MAX WINDS
INIT 31/0000Z 17.2N 123.4W 110 KT 125 MPH
12H 31/0600Z 17.1N 124.2W 120 KT 140 MPH
24H 31/1800Z 17.3N 125.8W 120 KT 140 MPH
36H 01/0600Z 17.6N 127.6W 115 KT 130 MPH
48H 01/1800Z 18.0N 129.4W 110 KT 125 MPH
60H 02/0600Z 18.6N 131.3W 105 KT 120 MPH
72H 02/1800Z 19.0N 132.9W 95 KT 110 MPH
96H 03/1800Z 19.9N 136.2W 85 KT 100 MPH
120H 04/1800Z 20.7N 139.3W 70 KT 80 MPH
$$
Forecaster Adams
NNNN
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.
WDPN33 PGTW 300900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (BANG-LANG) WARNING
NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 33.3N 167.3E
INITIAL INTENSITY: 45 KTS
GEOGRAPHIC REFERENCE: 841 NM NORTH OF WAKE ISLAND
MOVEMENT PAST 6 HOURS: NORTHWARD AT 26 KTS
SIGNIFICANT WAVE HEIGHT: 18 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAPIDLY
DETERIORATING CONVECTIVE STRUCTURE ASSOCIATED WITH TROPICAL STORM
(TS) 20W. IN THE PAST 24 HOURS, THE CENTRAL DENSE OVERCAST AND
NASCENT EYE FEATURE QUICKLY DEVOLVED INTO A CONVECTIVE BAND
ISOLATED TO THE NORTHERN PERIPHERY. THE CIRCULATION IS BECOMING
EMBEDDED IN A LARGE CLOUD BAND, UNDER WHICH THERE IS AN EXTENSIVE
SOUTH-SOUTHEASTERLY WIND FETCH OF 20-30 KTS. THE HIGHLY COMPACT
LOW-LEVEL CIRCULATION CENTER (LLCC) IS FULLY OBSCURED BY DEEP
CONVECTION AND THE SURROUNDING MID- TO UPPER-LEVEL CLOUDS. THE
ENVIRONMENT IS UNFAVORABLE, CHARACTERIZED BY STRONG POLEWARD
OUTFLOW THAT IS BEING OFFSET BY COOL SEA SURFACE TEMPERATURES
(SST). THE SUSTAINED CONVECTION IS THE RESULT OF COLDER AIR IN THE
UPPER TROPOSPHERE AND STRONG DIVERGENCE ALOFT. A 300425Z SSMIS PASS
REVEALED A HOOK-SHAPED RAIN BAND ALONG THE NORTHERN PERIPHERY. THE
INITIAL POSITION IS ASSESSED WITH LOW CONFIDENCE BASED ON THE
EXTRAPOLATION OF THE PREVIOUSLY VISIBLE, PARTIALLY EXPOSED LLCC AND
A LARGE SPREAD AMONG THE AGENCY FIXES. THE INITIAL INTENSITY HAS
BEEN LOWERED TO 45 KTS WITH LOW CONFIDENCE, SUPPORTED BY A BLEND OF
THE OBJECTIVE ESTIMATES FROM CIMSS. THE LOWER FINAL T-NUMBERS FROM
THE SUBJECTIVE DVORAK ESTIMATES OF 2.5-3.5 SUPPORT THE LOWER
INTENSITY.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: BINARY INTERACTION WITH TROPICAL
DEPRESSION (TD) 21W AND THE SOUTHWESTERN FLANK OF AN EXTENSIVE
RIDGE POSITIONED OVER THE CENTRAL NORTH PACIFIC
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.5 - 77 KTS
RJTD: T3.5 - 55 KTS
RCTP: T3.5 - 55 KTS
KNES: T4.0 - 65 KTS
CIMSS SATCON: 43 KTS AT 300340Z
CIMSS ADT: 39 KTS AT 300610Z
CIMSS AIDT: 43 KTS AT 300610Z
CIMSS D-MINT: 37 KTS AT 300516Z
CIMSS D-PRINT: 34 KTS AT 300610Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 10-15 KTS
SST: 25-26 CELSIUS
OUTFLOW: STRONG POLEWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: LOW
INITIAL INTENSITY: LOW
INITIAL WIND RADII: LOW
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: A MID-LEVEL RIDGE POSITIONED EAST OF THE
DATELINE IS THE PRIMARY STEERING MECHANISM OF TS 20W, BRINGING THE
SYSTEM POLEWARD AT A FORWARD SPEED OF 25-30 KTS. OVER THE PAST 6-12
HOURS, THE SYSTEM HAS TURNED SLIGHTLY WEST OF NORTH DUE TO THE
INTERACTION WITH TD 21W LOCATED APPROXIMATELY 180 NM TO THE
SOUTHWEST. TS 20W WILL PULL AWAY FROM TD 21W IN THE NEXT 12 HOURS,
AND THE STORM MOTION WILL RESUME A POLEWARD TRAJECTORY. A TROUGH
PASSING TO THE NORTH WILL IMPART A NORTH-NORTHEAST MOTION BY TAU
36. THE CIRCULATION CROSSED THE 26 DEGREE CELSIUS ISOTHERM 06 HOURS
AGO AND WILL TRAVERSE OVER GRADUALLY COOLER WATERS THROUGH THE
FORECAST PERIOD. THIS WILL LEAD TO GRADUAL WEAKENING THROUGH TAU 24
AS THE SYSTEM UNDERGOES SUBTROPICAL TRANSITION. IT WILL BECOME A
SUBTROPICAL STORM BY TAU 36. THE PROXIMITY OF TS 20W TO TD 21W HAS
INTRODUCED NEW FORECAST UNCERTAINTY. THERE IS NOW A DISTINCT
POSSIBILITY THAT TS 20W COULD MERGE WITH TD 21W. UNDER THIS
SCENARIO, THE CIRCULATION WOULD CONTINUE TO BEND TOWARD THE WEST
AND EVENTUALLY SOUTH. STEADY WEAKENING WOULD OCCUR UNTIL THE TWO
CIRCULATIONS MERGE, AFTER WHICH TIME THE END RESULT WOULD LIKELY BE
A TROPICAL DISTURBANCE OR DEPRESSION.
MODEL DISCUSSION: THE MAJORITY OF THE MODEL TRA…
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 301500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 21W (ETAU) WARNING
NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 31.1N 166.0E
INITIAL INTENSITY: 30 KTS
GEOGRAPHIC REFERENCE: 709 NM NORTH OF WAKE ISLAND
MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 07 KTS
SIGNIFICANT WAVE HEIGHT: 10 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT, PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
MEAGER CONVECTIVE ACTIVITY FLARING ALONG THE SOUTHEAST PERIPHERY.
THIS TINY SURFACE CIRCULATION WAS CAPTURED BY A 300941Z ASCAT-C
PASS, WHICH MEASURED WINDS NEAR 30 KTS IN THE SOUTHEAST QUADRANT.
AN UPPER-LEVEL LOW PRESENTLY SITS OVERHEAD, SEVERELY RESTRICTING
OUTFLOW ALOFT. THE SYSTEM IS ALSO TRAVERSING MARGINALLY WARM SEA
SURFACE TEMPERATURES (SST) OF 26-27 DEGREES CELSIUS AND IS
SURROUNDED BY DRY AIR. THESE ENVIRONMENTAL FACTORS ARE UNFAVORABLE
FOR TROPICAL CYCLONE DEVELOPMENT. CONSEQUENTLY, THE CONVECTIVE
ACTIVITY HAS BEEN MINIMAL, LEAVING THE LLCC INCREASINGLY FRAGILE.
THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
PARTIALLY EXPOSED LLCC IN THE SHORTWAVE-INFRARED IMAGERY. THE
INITIAL INTENSITY HAS BEEN HELD AT 30 KTS WITH HIGH CONFIDENCE
BASED ON THE SCATTEROMETER DATA, SUPPORTED BY A BLEND OF AGENCY
SUBJECTIVE DVORAK FIXES AND OBJECTIVE ESTIMATES FROM CIMSS.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: BINARY INTERACTION WITH TROPICAL STORM
(TS) 20W AND AN EXTENSIVE RIDGE POSITIONED OVER THE CENTRAL NORTH
PACIFIC
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.0 - 30 KTS
RJTD: T2.5 - 35 KTS
RCTP: T1.5 - 25 KTS
CIMSS ADT: 29 KTS AT 301210Z
CIMSS AIDT: 25 KTS AT 301210Z
CIMSS D-MINT: 35 KTS AT 301038Z
CIMSS D-PRINT: 30 KTS AT 301210Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 10-15 KTS
SST: 26-27 CELSIUS
OUTFLOW: WEAK POLEWARD
OTHER FACTORS: UPPER-LEVEL LOW OVERHEAD AND SURROUNDING DRY AIR
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: HAVING COMPLETED A 180-DEGREE SOUTHWARD LOOP
INDUCED BY THE FUJIWHARA EFFECT, TD 21W HAS BEGUN TO TURN POLEWARD
AS ITS DISTANCE FROM TS 20W INCREASES. THIS POLEWARD MOTION WILL
NOW BE DRIVEN BY THE STEERING INFLUENCE OF A LARGE ANTICYCLONE
POSITIONED OVER THE CENTRAL NORTH PACIFIC. ALTHOUGH THE LLCC IS
UNRAVELING, THE FORECAST HOLDS THE INTENSITY AT 30 KTS FOR THE NEXT
36 HOURS. THE CIRCULATION WILL BECOME EMBEDDED IN 25-30 KTS OF
SOUTHERLY LOW-LEVEL FLOW. THE EVENTUAL DEMISE OF THE TROPICAL
SYSTEM WILL BE DRIVEN BY TWO COMPETING, THOUGH NOT MUTUALLY
EXCLUSIVE, FACTORS. FIRST, THE POLEWARD TRACK WILL BRING THE SYSTEM
OVER PROGRESSIVELY COOLER SST AND INTO A MORE BAROCLINIC
ENVIRONMENT, CAUSING IT TO GRADUALLY ACQUIRE SUBTROPICAL
CHARACTERISTICS. THE SECOND FACTOR INVOLVES THE SURVIVABILITY OF
THE LLCC. THE FRAGILE CIRCULATION COULD DISSIPATE BEFORE
SUBTROPICAL TRANSITION IS COMPLETE. THE CURRENT FORECAST OF 36
HOURS IN DURATION MAY BE GENEROUS, AND IT IS QUITE POSSIBLE THAT
THE CIRCULATION COULD DEVOLVE INTO AN OPEN WAVE BY TAU 24 OR
SOONER.
MODEL DISCUSSION: FOR THE FIRST TIME, NUMEROUS MODELS LOSE TRACK OF
THIS WEAK, COMPACT CIRCULATION AND INADVERTENTLY LATCH ONTO THE
STRONG VORTEX OF TS 20W AFTER TAU 12. THEREFORE, THE JTWC FORECAST
TRACK IS PLACED ALONG A BLEND OF THE RELIABLE TRACKERS, HEDGED
TOWARD THE PREVIOUS FORECAST TRACK. AVAILABLE INTENSITY GUIDANCE IS
SIMILARLY SPARSE. THE JTWC INTENSITY FORECAST ALIGNS WITH THE
ESTABLISHED FORECAST…
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.
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: SE (140°), 9.7 kt | Gust: 11.7 kt
Pressure: 29.93 | Air Temp: 84.7 °F
Water Temp: 87.3 °F | Dew Point: 79.0 °F
Swell: 1.6 ft | Wind Wave: 0.7 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.
