Variations and trends in extreme climate events have only recently received much attention. Exponentially increasing economic losses, coupled with an increase deaths due to these events, focused attention on the possibility that are frequency. One of major problems examining record for changes extremes is a lack high-quality, long-term data. In some areas world increases apparent, while others there appears be decline. Based this information increased ability monitor detect multidecadal...

Projections of statistical aspects weather and climate extremes can be derived from models representing possible future states. Some the recent have reproduced results previously reported in Intergovernmental Panel on Climate Change (IPCC) Second Assessment Report, such as a greater frequency extreme warm days lower cold associated with warmer mean climate, decrease diurnal temperature range higher nighttime temperatures, increased precipitation intensity, midcontinent summer drying,...

Weather and climatic extremes can have serious damaging effects on human society infrastructure as well ecosystems wildlife. Thus, they are usually the main focus of attention news media in reports climate. There some indications from observations concerning how may changed past. Climate models show could change future either due to natural climate fluctuations or under conditions greenhouse gas-induced warming. These observed modeled changes relate directly understanding socioeconomic...

A significant number of tropical cyclones move into the midlatitudes and transform extratropical cyclones. This process is generally referred to as transition (ET). During ET a cyclone frequently produces intense rainfall strong winds has increased forward motion, so that such systems pose serious threat land maritime activities. Changes in structure system it evolves from an during necessitate changes forecast strategies. In this paper brief climatology given challenges associated with...

A comprehensive climatology of extratropically transitioning tropical cyclones in the Atlantic basin is presented. Storm tracks and intensities over a period from 1899 to 1996 are examined. More detailed statistics presented only for most reliable record, beginning 1950. Since 1950, 46% transitioned extratropical phase. The coastal areas likely be impacted by cyclone northeast United States Canadian Maritimes (1–2 storms per year), western Europe (once every 1–2 yr). Extratropically...

Abstract The extratropical transition (ET) of tropical cyclones often has an important impact on the nature and predictability midlatitude flow. This review synthesizes current understanding dynamical physical processes that govern this highlights relationship downstream development during ET to high-impact weather, with a focus regions. It updates previous from 2003 identifies new emerging challenges future research needs. First, mechanisms through which transitioning cyclone impacts flow...

Abstract Forty-six percent of Atlantic tropical storms undergo a process extratropical transition (ET) in which the storm evolves from cyclone to baroclinic system. In this paper, structural evolution base set 61 cyclones that underwent between 1979 and 1993 is examined. Objective indicators for onset completion are empirically determined using National Hurricane Center (NHC) best-track data, ECMWF 1.125° × reanalyses, operational NCEP Aviation Model (AVN) U.S. Navy Operational Global...

A 50-yr climatology (1957–2007) of subtropical cyclones (STs) in the South Atlantic is developed and analyzed. cyclone a hybrid structure (upper-level cold core lower-level warm core) with associated surface gale-force winds. The tendency for season development North STs has resulted these systems being confused as tropical (TCs). In fact, are regular source incipient vortices leading to TC genesis. 2004, Hurricane Catarina made landfall Brazil. system had been previously unobserved...

Abstract The authors present a global climatology of tropical cyclones (TCs) that undergo extratropical transition (ET). ET is objectively defined based on TC’s trajectory through the cyclone phase space (CPS), which calculated using storm tracks from 1979–2017 best track data and geopotential height fields reanalysis datasets. Two reanalyses are used compared for this purpose, Japanese 55-yr Reanalysis ECMWF interim reanalysis. results to study seasonal geographical distributions storms...

Abstract This study introduces the development of Tracking Algorithm for Mesoscale Convective Systems (TAMS), an algorithm that allows identifying, tracking, classifying, and assigning rainfall to mesoscale convective systems (MCSs). TAMS combines area-overlapping projected-cloud-edge tracking techniques maximize probability detecting progression a system through time, accounting splits mergers. The combination projection on area overlapping is equivalent setting background flow in which...

Increased occurrence of more intense tropical storms intruding further poleward has been foreshadowed as one the potential consequences global warming. This scenario is based almost entirely on general circulation model predictions warmer sea surface temperature (SST) with increasing levels atmospheric C02 and some theories cyclone intensification that support notion systems SST. Whether are able to achieve this theoretically determined state depends whether underlying water dominant factor...

Abstract Streamfunction and velocity potential fields, calculated from monthly averaged station data sets, are composited for ENSO anti‐ENSO extremes in the Australasian region. Four January four February sets used each of composites. Gridded sea‐surface temperature (SST) highly reflective cloud (HRC) a similar manner. These to investigate effect phase on summer monsoon tropical cyclone activity Changes structure found be consistent with cyclogenesis track data. effects extend north west...

Abstract A 34-member ensemble-mean trajectory through the cyclone phase space (CPS) is calculated using Navy Operational Global Atmospheric Prediction System (NOGAPS) analyses for North Atlantic tropical cyclones (TCs) undergoing extratropical transition (ET). Synoptic composites at four ET milestones are examined: 24 h prior to beginning of (TB − 24), (TB), end (TE), and after (TE + 24). While extratropically transitioning TC structure tightly constrained in its phase, it has a variety...

The Gray Yearly Genesis Parameter (YGP) is an empirical diagnostic tool used to infer regions in which necessary (but not sufficient) conditions exist for tropical cyclone development. This parameter here as a measure of the implied frequency and area occurrence climate simulations generated by General Circulation Model (GCM). In simulation current climate, CSIRO9 GCM shows reasonable agreement with original climatology. YGP doubled CO 2 presented.

Subtropical cyclones (ST) have only recently gained attention as damaging weather systems. A set of criteria for identifying and classifying these systems is introduced here employed to identify 18 ST cases forming in the 1999–2004 hurricane seasons. To be classified an ST, must near-surface gale-force winds show hybrid structure more than one diurnal cycle. The are partitioned into four classes based upon their genesis environments. Genesis over waters with SST excess 25°C observed almost...

Abstract A 45-yr climatology of subtropical cyclones (ST) for the North Atlantic is presented and analyzed. The STs pose a warm-season forecasting problem locations such as Bermuda southern United States because potentially rapid onset gale-force winds close to land. Criteria identification ST have been developed based on an accompanying case-study analysis. These criteria are applied here 40-yr European Centre Medium-Range Weather Forecasts Re-Analysis (ERA-40) construct consistent...

Using the historical Atlantic tropical cyclone record, this study examines empirical relationships between climate state variables and counts. The considered as predictors include indices of El Niño/Southern Oscillation Northern Oscillation, both “local” “relative” measures Main Development Region sea surface temperature. Other measuring Meridional Mode West African monsoon. all potential in a forward stepwise Poisson regression, we examine counts variables. As further extension on past...

Gray's seasonal genesis parameter (SGP) is reassessed as a diagnostic quantity for both climatological and single-season tropical cyclogenesis. The SGP applied to global analyses from recent years able locate the regions of activity during 1967–86. based on climatology simulation by CSIR09 atmospheric model using prescribed ocean temperatures 1979–88 has similar skill. means then assessed interannual variation Increased cyclogenesis in central Pacific 1982/83 El Niño coincides with increased...

[1] The characteristics of the extratropical transition (ET) tropical cyclones and its impact on midlatitude flow are examined in THORPEX Interactive Grand Global Ensemble (TIGGE) multimodel ensemble prediction system (EPS). Ten forecasts initialized prior to ET for five 2008 investigated using an empirical orthogonal function analysis fuzzy clustering methodology. Each forecast contains 231 members from eight different global EPS. The EPS contributing TIGGE differ their spread contributions...

Abstract An African easterly wave (AEW) and associated mesoscale convective systems (MCSs) dataset has been created used to evaluate the propagation of MCSs, AEWs, and, especially, MCSs relative AEW with which they are (i.e., wave-relative framework). The thermodynamic characteristics AEW–MCS also analyzed. analysis is done for both that develop into tropical cyclones those do not quantify significant differences. It shown developing AEWs over West Africa a larger number cloud clusters...

Abstract The behavior in the South Asian summer monsoon (SASM) was analyzed Coupled Model Intercomparison Project (CMIP3) multimodel historical (20c3m) simulations and modern observational reanalysis data. CMIP3 capture observed trend of weakening SASM circulation over past half century, but are unable to reproduce magnitude trend. While observations indicate a slight decrease SASM-related precipitation, on average very increase, albeit with large intermodel intramodel variabilities....

Sea surface temperatures (SSTs) contribute to modulation of deep convection over tropical oceans.Using a threshold value outgoing long-wave radiation (OLR) as proxy for convection, regional and temporal relationships between SST its variability are examined.Based on this approach, an 27.5°C across the global tropics is identified; in agreement with critical around 27°C onset identified previous studies.Monthly variations (SST MON-CRIT ) required also identified.SST exhibits interannual...

Abstract Since more research is needed on subtropical cyclones (STCs) formed within the North Atlantic eastern basin, this survey analyzes them from a synoptic point of view, climatological basis, with main aims studying their common features, complementing other studies these storms in Atlantic, and aiding forecasting community. Fifteen cases STCs were identified during period 1979–2011 by applying set criteria two databases. Composite analysis reveals that an extratropical depression acts...

A series of barotropic modeling experiments are used to examine the motion a vortex in vicinity an idealized subtropical ridge. The propagation is highly correlated with absolute vorticity gradient initial imposed environment. signal degraded when radial band averages calculate environmental advection and components. It shown here that this due partially difficulties separating cyclone from its Application results climatological mean fields indicates considerable variations can occur.