BFB: 9/29/2015 Tropical Weather Zach Hiris & Phil Pascarelli

Tropical System Characteristics Warm core systems (center of storm is warmer than the surroundings) No frontal boundaries Eye- Closed center of circulation Eyewall- Strongest winds occur just outside of the eye Size of storm does not determine strength

Tropical vs. Extra-Tropical Storms Extratropical/Non-Tropical systems are typically larger and size and have larger wind fields (Sandy 2012) Extratropical/Non-tropical systems are not affected by friction over land Warm Core vs. Cold Core

Warm Core vs. Cold Core Cold Core Warm Core Air in low is colder than the surrounding environment Gets stronger with height Warm Core Air in low is warmer than the surrounding environment Gets weaker with height

Tropical Weather Development Occurs between 23.5° N/S Main areas of Tropical Cyclones North Atlantic East Pacific Central Pacific West Pacific Indian Ocean Caribbean/Gulf of Mexico

Timeframe for Tropical Weather Atlantic Ocean: June 1st to November 30th East Pacific: May 15th to November 30th West Pacific: Nearly all year Just because Hurricane Season runs from June-November doesn’t mean storms can’t form outside those dates!

Stages of Development (NHC) Tropical Wave Surface trough/low pressure system which usually originates from the ITCZ (Intertropical Convergence Zone) Tropical Depression Closed area of low pressure, with winds of < 39 mph Aren’t given a name, but a # based on the number of storms in the season Tropical Storm Tropical system with winds between 39-73 mph. Given names Hurricanes Tropical system with winds >74 mph Major Hurricanes - winds >111 mph

Developing Storms- What to Look For? Tropical Wave/Trough High moisture content High PWATs, Low SAL Low Shear Good low-level convergence (ITCZ) Warm Ocean temperatures (>80°F)

What to Look For- Observations Upper Level Shear (Left) & Upper Level Divergence (Right)- From CIMSS

What to Look For- Observations SST (°C), WindSat, and Model Forecast tracks (TD Ida)

What to Look For- Satellite (IR/VIS)

WTLF- Satellite (Microwave/Other)

What to Look For - Models

Advanced- Cyclone Phase Maps From Florida State- Used by the NHC to determine Tropical vs. Extratropical

Cyclone Intensity Forecasts Dvorak Method- Universal measure of cyclone intensity Uses satellite analysis to determine a T-value (Intensity score) Can be used for anything from Tropical Waves to Strong Typhoons Not always reliable estimator- Aircraft data is almost always more important!

Dvorak Example For Typhoon Dujuan:

Famous Hurricanes- Andrew Last Category 5 Hurricane to make landfall in the U.S. Rapidly intensified from a weak system to a Cat. 5 storm within 48 hours Landfall just south of Miami (NHC Headquarters)

Famous Hurricanes- Sandy Famous Hurricane which eventually made landfall in New Jersey Was considered extratropical at the time of landfall Significant damage to NJ/NY, etc. Also produced heavy snowfall in the Appalachains

Hurricane Sandy

Famous Typhoon- Haiyan One of the strongest storms in history 895mb Central Pressure, 195mph Sustained 1m Winds Killed over 6,000 people in the Phillipines and caused over $2 Billion in damage