HURRICANE IRENE October 1999

1
Cyclone Phase Space for Atlantic Warm-Seclusion
Irene Eddy Momentum Flux Convergence During
Frontal Fracture units of (ms-1) day-1
Frontal Fracture
08z
11z
14z
Frontal Fracture
SUMMARY AND FUTURE DIRECTIONS
TYPHOON KOPPU (September 2003) POST-EXTRATROPICAL
TRANSITION WARM SECLUSION

• Since the study only considers precursor
  disturbances that culminate into mature warm
  seclusions, it is important to find the point at
  which the different cyclone evolutions (tropical
  vs. extratropical) converge. On the CPS, this
  point is the maximum asymmetry / deepest cold
  core and is associated with the tropopause
  folding. However, the preconditioning of the
  upper-level PV anomaly responsible for the PV
  intrusion differs considerably between tropical
  and extratropical cyclones. The massive amount
  of warm outflow with a poleward translating TC
  may begin to affect the midlatitude tropopause
  many days before impingement. Conversely, a
  short-scale shallow warm-core wave which slowly
  builds (essentially from the bottom up) must
  increase via convective means until reaching a
  scale commensurate with the Rossby penetration
  depth to interact with the upper-PV anomaly.
• To what effect does latent heating contribute
  to the scale matching necessary for baroclinic
• coupling for warm seclusion cyclones?
• What signatures foretell when a tropical
  remnant vortex will yield a warm seclusion?
• What signatures foretell when an extratropical
  vortex will yield a warm seclusion?
• What are the structural differences between the
  final warm seclusions from the different
  precursor
• disturbances? This is an important concern
  for forecasting sting jets.

Ex-tropical PV tower
NORTH
NORTH
Descent
Warm seclusion (Irene) QuikSCAT Winds (m/s)
Complete Cyclone Lifecycle of Irene (1999)
PV intrusion looking eastward (left) and from the
west (right) at 03z 09/20/03. The 2 PVU surface
is colored with vertical motion (m/s).
Red/orange indicates ascent while blue/green
shows descent.
HURRICANE IRENE (October 1999) POST-EXTRATROPICAL
TRANSITION WARM SECLUSION
Narrow PV Intrusion
PV Streamer
NORTH
ACKNOWLEDGEMENTS
NORTH

• Center for Ocean-Atmospheric Prediction
  Studies. COAPS receives its base funding from
  the
• ONR, Secretary of the Navy Grant awarded to
  James J. OBrien and by the NASA Office of Earth
• Science Grant. The first author owes a debt
  of gratitude to various computers for their hard
  work
• as well as various talk radio stations for
  inspiration during the analysis process.
  References
• available at Ryan N. Maue. COAPS, Florida
  State University, Department of Meteorology, 404
  Love Building,
• Tallahassee, FL 32306-4520.
  rmaue_at_met.fsu.edu

Warm frontogenesis
As for Koppu above, but for post-ET Irene at 08z
10/20/99 centered off Canadian Maritimes.