tracking and forecasting hurricanes by john metz warning coordination meteorologist nws corpus...
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Tracking and ForecastingTracking and ForecastingHurricanesHurricanes
By John MetzWarning Coordination MeteorologistNWS Corpus Christi, Texas
NATIONAL HURRICANE CENTERMIAMI, FLORIDA
NATIONAL HURRICANE CENTERMIAMI, FLORIDA
Hurricane Track Forecasting
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Overview of Models
• Statistical Models: CLIPER, NHC90, NHC91, NHC98, SHIFOR, SHIPS, DSHIPS
• Steering models: BAMS, BAMM, and BAMD
• Simplified Dynamic Models: LBAR
• 3-D Dynamic Models:GFS, NOGAPS, UKMET, ECMWF, Canadian, Japanese, GFDL, GFDN, HWRF
• Ensemble Models: TCOA, TVCA, TCCN, TVCC, CGUN, FSSU
Don’t know anything aboutCurrent state of the atmosphere
Know basic general information about current state of atmosphere
Know basic general information about current state of atmosphere
Most powerful models that know a lot about current state of atmosphere
Statistical models that average the output from 3-D dynamic models. Can reduce biases in models with good results.
EGRI
GFDL
NGPGFS
Summary
• There have been big advances in track forecasting by dynamical models over the past several years
• A consensus of high-quality track prediction models is an extremely powerful tool for track prediction
• Sound meteorological reasoning is still needed to get the most out of model-predicted tracks
• Improved observation of the environment, has had a positive impact on track predictions by the NCEP global model (GFS)
Intensity ForecastingIntensity Forecasting
Hurricane Claudette
Example – Hurricane Claudette
Wind Direction
Hurricane Claudette
• Satellite imagery using the Dvorak technique.
• Surface observations: ships, buoys, land stations (infrequent)
• Satellite imagery using the Dvorak technique.
• Surface observations: ships, buoys, land stations (infrequent)
• Aircraft reconnaissance
flight-level winds
• Aircraft reconnaissance
flight-level winds
• GPS dropwindsondes
• GPS dropwindsondes
Estimating Intensity
Tropical cyclones have characteristic cloud patterns that correspond to stages of development and certain intensities.
The Dvorak Technique
Satellite Wind Data
High Resolution
Super High Resolution
Available Today
Future?
105 kt
90 kt
90 kt95 kt
Aircraft Reconnaissance
Observations taken at 10,000 ft are used to estimate intensity
Friction decreases wind in the lowest 1500 ft of the eyewall.
Dropsonde
NASA’s Global Hawk Unmanned Airborne System
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Hurricane Earl’s eye as seen from the Global Hawk
• Intensity forecasting is not as advanced as track forecasting. Intensity skill essentially goes to zero by 5 days. Do not expect the wind speed predictions beyond 3 days to be skillful.
• Current guidance is provided mainly by statistical models. Improvements in these models, using oceanic heat content, inner core convection, and rapid intensification criteria, are currently being made.
• Dynamical models have shown little or no skill in intensity forecasting. However, in time, improvements to these models offer hope for the future.
Summary
The End