Identify and interpret broad scale, synoptic and mesoscale systems
A new conceptual model on Mediterranean hurricanes - "Medicanes".
Medicanes are rare, intense and destructive warm-core cyclones occasionally generated in Mediterranean Basin.
Compared with tropical cyclones, medicanes are weaker and smaller in size, with diameters under 300 km, while the diameter of a hurricane is larger than 1000 km. Hurricanes move in general from east to west due to easterly winds, while medicanes generally (but not always) move from west to east due to the mid-latitude westerlies.
Medicanes mostly occur in the western Mediterranean and in the region extending from the Ionian Sea to the North African coast. There is strong variability from year to year without any significant trends.
Pilar Rípodas talks about the improvements that the MTG will bring in regards to NWC SAF products.
The Nowcasting SAF (NWC SAF) develops and distributes software packages to generate satellite derived products with application in nowcasting. Cloud products, precipitation products, stability product, wind product, convection products, products related to turbulence and extrapolation imagery are current products in the NWC SAF portfolio. A version of the NWC SAF software that supports the new EUMETSAT satellite MTG-I is been developed by the NWC SAF team. The first version (MTG day-1) is expected to be released early 2024. The improvements expected in the NWC SAF products in this version are presented. Some preliminary products with MTG-I data can be presented depending on the availability of data. A full exploitation of the new capabilities of MTG-I to improve the current NWC SAF products and to develop new ones will come in the following versions. The plans in this respect are presented.
Martin Setvak demonstrates comparison between new FCI data with MSG and VIIRS, focusing on convective storms.
This case study describes the evolution and the life cycle of hurricanes in general and the evolution of hurricane Ophelia (2017) in particular.
This module and the adjoined simulator treat the hurricane Ophelia that threatened Europe in 2017 and hit the coast of Ireland in October that year.
In this module, you will learn more about hurricanes in general and about the evolution of Ophelia in particular from the very beginning over the Atlantic until its final stage over Ireland.
In the adjoined simulator, you will forecast the warnings related to hurricane Ophelia and the dangers that arose with this weather situation.
Vesa Nietosvaara showcases how the MTG's FCI instrument will improve the quality of satellite data, especially for users in high latitudes.
The first Meteosat Third Generation (MTG-I) satellite with Flexible Combined Instrument (FCI) was launched at the end of 2022. It will be followed later in 2024 by MTG-S Satellite with Infrared Sounder onboard. MTG will carry novelty instruments – Infrared Sounder, Lightning Imager and Ultraviolet Visible Near-infrared (UVN) Spectrometer - in the GEO orbit. Meteosat Third Generation aims to secure continuity and to increase the capabilities of the Meteosat satellites in response to requirements of the future forecast/nowcast systems. Altogether, the new and enhanced capabilities will allow us to make a huge step in better monitoring of our environment, and allowing development of new applications.
Gunnar Noer explains and showcases the nature of polar lows.
Polar lows are small but fairly intense low pressure systems that form in the Arctic marine regions during the winter season. They form in unstable air masses associated with cold air outbreaks from the Arctic ice cap. Polar Lows give rise to gale or storm force winds which, in combination with heavy snowfall, cause widespread traffic disruptions. In recent years, polar lows have caused several fatal incidents with snow avalanches. This lecture focuses on the key processes and the methodology for forecasting polar lows.
Thomas Krennert (ZAMG) talks about the importance of moisture gradients in analysing the possibility of development of deep moist convection.
The exact predictability of convection in the Alpine region in the absence of fronts in weak-surface-pressure-gradient-situations during the warm season remains challenging for forecasters. The development into single-cell deep moist convection SC-DMC under these conditions depends on the availability of well-known ingredients like low level moisture, steep tropospheric lapse rates and sufficient lift. Satellite studies have shown that favourable locations for the first onset of SC-DMC resulting from widespread shallow convection over mountainous terrain are water vapour gradients in the middle or upper troposphere UTMG (upper tropospheric moisture gradients, Krennert, et al., 2003, https://doi.org/10.1016/S0169-8095(03)00067-X). The contributions of the respective ingredients related to UTMG supporting the initiation of DMC are discussed. A focus is set on moist symmetric instability MSI as a possible mechanism for favouring the transition from shallow to deep moist convection.
Wilfried Jacobs (DWD) explains the power of Airmass RGB in estimating the possibility of cold front transforming into a convective line.
Especially, the airmass RGB is a powerful tool for estimating the cold front’s tendency to transform to a convective line. Convective lines are connected with strong gusts, heavy precipitation sometimes with graupel or even hail. During this presentation the indications of convective lines will be outlined by considering the airmass RGB together with other means, e.g., radiosounding. Examples of two succeeding days will be discussed in detail whereas the first case did not lead to a convective line whereas the second example did. Typical differences of patterns in the corresponding airmass RGB and additional data sources will be related to a convective line’s probability.
Andreas Wirth (ZAMG) presents the benefits of analysing the water vapour imagery to diagnose synoptic structures and weather patterns.
Water vapor (WV) imagery is very useful when it comes to visualize zonal and meridional transport of air masses, but it is also suited to get a rapid overview on vertical transport processes. This characteristic makes WV-imagery extremely helpful when it comes to diagnose fronts and cyclogenesis.
The presentation will focus on the dynamics of cyclogenesis and fronts and how they are reflected in WV-imagery. The concept of relative streams will be introduced in the context of cyclogenesis, ana- and kata fronts.
Meteorological products based on WV absorption bands such as the Total Precipitable Water product will be introduced and their usefulness will be demonstrated on case examples.
Christo Georgiev (NIMH) presents influence of synoptic and mesoscale dynamical process, through water vapour imagery, on the intensification of wildfires.
Studies of large fires in Australia, Tasmania, USA and Southeastern Europe have shown a link between fire activity and dry stratospheric intrusions with downward transport of energy and momentum down to the lower troposphere. In such cases the rapid increase of fire activity was accompanied by a dry band in satellite Water Vapour (WV) imagery, which is indicative of pronounced descent of upper-tropospheric or stratospheric air which is normally much dryer than the lower tropospheric one and has much higher potential vorticity. When these descending air masses, reach the Earth’s surface they affect the wind speed, moisture and ozone concentration, which could generate a spike in fire activity.
Case-study examples of such severe events over areas of Central and Eastern Mediterranean are considered in the presentation. Combination of WV imagery, satellite soundings and satellite estimations of fire radiative energy contribute to better understanding of dry stratospheric intrusion depth and related dynamical processes, which govern the intensification of wildfire occurrence and spread.
Christo Georgiev (NIMH) discusses the effect of vorticity on tropical cyclones and development of severe thunderstorms, through the scope of water vapour imagery.
Water vapour (WV) images provide useful information to anticipate the effects of upper-level dynamic environment on the intensity of a tropical cyclone (TC) as well as on its extratropical transition (ET), a gradual process in which a TC loses tropical characteristics and becomes more extratropical in nature. Analyses of WV imagery shows that during ET stage over subtropical areas, advection of potential vorticty anomaly can influence the ET and control the process.
Large amounts of water vapour, originated by TCs may be involved in transfer of moisture by planetary waves, associated with ET developments and give rise to a narrow regions of strong meridional water vapour flux. The presentation shows WV imagery synoptic-scale analysis, which shows supply with additional large amount of moisture of an existing already favourable convective environment. The
combination lead into an environment with very high CAPE and potential to accelerate upward, acquiring kinetic energy and forming strong vertical motions in a deep tropospheric layer. The process is illustrated by a case of catastrophic hailstorm over Bulgaria, Eastern Mediterranean.
Nataša Strelec-Mahović (EUMETSAT) shows and analyses several cases of water vapour structures in the atmosphere using satellite imagery.
Features occurring in the WV6.2μm images indicate the processes going on in the atmosphere, since these dark (dry) and white (moist) structures result from a combination of vertical motion, moisture advection and horizontal deformation within the mid and upper troposphere. Frequently, water vapour images reveal structures such as dark stripes, mountain wave signatures, or circular or spiral formations known as water vapour eyes, eddies or vortices. We will look at how these features can be used as tracers of three-dimensional atmospheric motions on the meso- and synoptic scale and how they relate to e.g. jet-streams, upper-level lows or turbulence.