“PREDICT” The field campaign, dropsondes, and early results William A. Komaromi MPO663 4-19-11 Final Project

“PREDICT”The field campaign,

dropsondes, and early results

William A. KomaromiMPO663

4-19-11Final Project

PREDICT Domain

above figure (and numerous within) courtesy Montgomery et al. 2011 (submitted)

Aug and Sep 2011

• Genesis– Difficult to model and forecast– Numerous field campaigns and

operational (Hurricane Hunters) flights into mature TCs, relatively few in-situ obs of pre-TCs

• Pouch theory– Broad region of cyclonic vorticity,

high moisture, low vertical shear “protects” localized vorticity maxima and convection within it

Co-moving streamlines (white) and regions of positive OW with cyclonic vorticity (light-blue and purple, color bar units of 10−9 s−2 ) at 700 hPa at 12 UTC 22 September derived from the ECMWF analysis. Superposed on these fields are AMSR-E 89 GHz brightness temperatures (units of K, green, yellow and red) from the 1818 UTC overpass. The pouch sweet spot defined by the intersection of the trough axis (black curve) and critical latitude (CL, purple curve) is highlighted by the black circle. AMSR-E brightness temperature is courtesy of NRL-Monterey.

PREDICT Dropsondes

PREDICT Dropsonde MissionsAug 15 Trop. Fntl. Conv.

Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L

Aug 30 pre- TS Fiona

Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L *

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl

Sep 20 pre- TS Matthew



Sep 24 TS Matthew

Sep 27 pre- TS Nicole

Sep 28 TS Nicole

Sep 30 pre- H Otto

* post-Gaston, expected to re-develop but did not

Take a “mean” environmental profile of genesis vs non-genesis cases

Q: Can we do this?A: Since PREDICT dropsondes are co-located with, and distributed (reasonably) evenly about, a center of circulation, comparison of mean environments should have “meaning”

Genesis vs. non-genesis?... Or take it a step further?

Aug 15 Trop. Fntl. Conv.

Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Invest regions that failed to develop: “non-genesis”


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Region of enhanced convection over Bahamas associated with old frontal system, also non-genesis but not a true invest either:“trop. fntl. conv.”


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Flights in which the invest becomes a TC within 24 h of investigation:“pre-gen. 0-24 h”


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Flights in which the invest becomes a TC within 24-48 h of investigation:“pre-gen. 24-48 h”


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Flights in which the invest becomes a TC within 48-72 h of investigation:“pre-gen. 48-72 h”


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Flights in which the invest becomes a TC in 72+ h from investigation:“pre-gen. 72+ h”


Aug 17 PGI27L

Aug 18 PGI27L

Aug 21 PGI30L

Aug 23 PGI30L


Aug 31 TS Fiona

Sep 1 TS Fiona

Sep 2 TS Gaston

Sep 3 PGI38L

Sep 5 PGI38L

Sep 6 PGI38L

Sep 7 PGI38L

Sep 10a pre- H Karl

Sep 10b pre- H Karl

Sep 11 pre- H Karl

Sep 12 pre- H Karl

Sep 13 pre- H Karl

Sep 14 pre- H Karl




Sep 24 TS Matthew


Sep 28 TS Nicole

Sep 30 pre- H Otto

Flights into named tropical cyclones / post-genesis:“TC Stage”

pre-gen.72+ h

example: Hurricane Karl

pre-gen.48-72 h

pre-gen.24-48 hpre-gen.

0-24 hTC Stage

Take the difference between each set of dropsondes and the PREDICT mean sonde:

A bit noisy…

Immediately before/after genesis (blue/green) vs non-genesis pouches and non-genesis convective regions (pink/red)

Time-progression from t = 72+ h before genesis through named TC stage

• Genesis much warmer than non-genesis, especially at upper levels

• Whole environment clearly progresses from cooler to warmer sounding at all levels of troposphere closer to genesis. Convective latent heat release?

• Genesis much more moist than non-genesis at upper-levels, comparable at lower-levels

• Little progress in moisture leading up to genesis, genesis environment simply moist to begin with

• TC winds much stronger than frontal winds, but no obvious separation between genesis and non-genesis

• Winds strengthen most at mid levels leading up to genesis… agrees with theory that steady convective warming (shown earlier) correlates well with steady strengthening of the mid-level vortex

• A rising parcel for the non-genesis cases is much more moist than its environment at mid levels (often associated with downdrafts), while developing cases are not

• Signal not obvious for pre-genesis time series

• Not surprisingly, cooler temperatures aloft in the non-developing cases generates greater instability / buoyancy. It appears that high instability and parcel buoyancy are not a necessary condition for tropical cyclogenesis

• Buoyancy anomaly profile for pre-genesis illustrates that warming at all levels as time progresses produces a fluctuating, but not trending, buoyancy profile

Conclusions

• Warm upper levels have been associated with genesis, while comparatively cooler upper-levels have been associated with non-genesis– Higher instability does not necessarily equate to TC genesis

• Environment progresses from cooler to warmer at all levels as genesis nears– Convective latent heat release?

• PREDICT genesis cases much more moist than non-genesis at upper-levels

• Winds strengthen most at mid levels leading up to genesis… agrees with theory that steady convective warming correlates well with steady strengthening of the mid-level vortex

Conclusions• Data extracted by averaging PREDICT dropsondes over different time

frames under different circumstances agrees well with theories of tropical cyclogenesis

• While promising, we do not have enough cases to assign “threshold” values of moisture / wind / etc. for genesis with statistical significance

• Cases with very high moisture / warm upper levels that do not develop and cases with comparatively lower moisture / cold upper levels that do develop certainly exist– It is likely impossible to define any thresholds for TC genesis that can be

extracted by the thermodynamic environment alone– Understanding the consolidation of vorticity, interaction of the vortex with

shear and many other dynamical processes are certainly needed to capture genesis

Additional (preliminary) results: Overshooting Tops

Additional (preliminary) results: Ensemble Forecasts

…future work

Additional (preliminary) results: Ensemble Forecasts

References• DeMaria, M., J.A. Knaff, and B.H. Connell, 2001: A Tropical Cyclone Genesis Parameter for the

Tropical Atlantic. Wea. Forecasting, 16, 219–233.

• Dunkerton, T. J., Montgomery, M. T., and Wang, Z., 2009: Tropical cyclogenesis in a tropical wave critical layer: easterly waves. Atmos. Chem. & Phys., 9, 5587-5646.

• Hawkins, J., and C. Velden, 2011: Supporting Meteorological Field Experiment Missions and Post-Mission Analysis with Satellite Digital Data and Products. Accepted in BAMS.

• McBride, John L., Raymond Zehr, 1981: Observational Analysis of Tropical Cyclone Formation. Part II: Comparison of Non-Developing versus Developing Systems. J. Atmos. Sci., 38, 1132-1151.

• Montgomery, M. T., C. A. Davis, T. Dunkerton, Z. Wang, C. S. Velden, R. D. Torn, S. J. Majumdar, F. Zhang, R. Smith, L. Bosart, M. Bell, J. Haase and M. Boothe. The Pre-Depression Investigation of Cloud Systems in the Tropics (PREDICT) Experiment: Scientific Basis, New Analysis Tools and Some First Results. Bull. Amer. Meteor. Soc., Submitted.

• Montgomery and Smith, 2010: Tropical-Cyclone Formation: Theory and Idealized modeling. Topic 2.1 of Seventh International Workshop in Tropical Cyclones, 23 pp.; Workshop held in November 2010 in La ReUnion. J. Kepert and J. Chan. Editors.

• Sippel, J. A., and F. Zhang, 2008: Probabilistic evaluation of the dynamics and predictability of tropical cyclogenesis. J. Atmos. Sci,, 65, 3440–3459.

• Torn, R. D., and G. J. Hakim, 2008: Ensemble-based Sensitivity Analysis. Mon. Wea. Rev., 136, 663–677.

Documents

“PREDICT” The field campaign, dropsondes, and early results William A. Komaromi MPO663 4-19-11 Final Project