A chronological list of updates and features to the NorLatMet site:
Here are two new publications of interest to the NorLatMet community:
Alberta Clipper Case Exercise
This case study focuses on a snow and blowing snow event in the Canadian prairies and US northern high plains on 11-13 November 2003. The key aim of this module is to step through the forecast process during an Alberta Clipper event from the perspective of a forecaster with the Meteorological Service of Canada. This involves consideration of various observations and model guidance, identification of potential areas of snowfall and blowing snow, nowcasting snowfall development and termination, and considering and providing nowcast updates throughout.
Recognition and Impact of Vorticity Maxima and Minima in Satellite Imagery
Vorticity maxima and minima signatures are common features of the atmosphere. They indicate areas of ascending and descending circulation and atmospheric forcing and can be used to diagnose dynamic features such as the axis of maximum winds and deformation zones. This module provides insight on the analysis of these dynamic atmospheric features using Meteosat Second Generation (MSG) satellite imagery. The module is an adaptation of Phil Chadwick's work from the series of modules in "Dynamic Feature Identification: The Satellite Palette".
Satellite Feature Identification:
"Ring of Fire" and "Blocking Patterns"
Satellite Feature Identification: Ring of Fire
Satellite Feature Identification: Ring of Fire introduces forecasters to the potentially damaging convection that can develop in conjunction with blocking high pressure centers and examines how to identify it from a water vapor imagery perspective.
Satellite Feature Identification: Blocking Patterns
Satellite Feature Identification: Blocking Patterns examines how water vapor imagery can be used to help diagnose blocking patterns and their dissipation. Four major blocking patterns are covered in this module: Blocking highs, Cut-off lows, Rex blocks and Omega blocks.
Dynamic Feature Identification:
"Introduction to the Satellite Palette" and
"The 10 Commandments of the Satellite Palette"
Our series on satellite meteorology and dynamic feature identification continues to grow. We’ve recently added two presentations, “Introduction to the Satellite Palette” and “The 10 Commandments of the Satellite Palette”. These two presentations provide an overview to the series, describing the need for improved satellite interpretation and a list of important tenets to keep in mind while working with remote sensing data.
Dynamic Feature Identification: DZ Diagnosis
Following an analysis of the main features of a deformation zone, the diagnosis of temporal and spatial changes in these features can be used to deduce underlying meteorological processes and their progression. In turn, this knowledge can then be used in the forecast process to adjust the forecast accordingly. This module takes 35-45 minutes to complete. It is part of the series: "Dynamic Feature Identification: The Satellite Palette".
Planetary Boundary Layer in Complex Terrain: Part 1 and Part 2
This 2-part Webcast is based on a presentation by Dr. David Whiteman on August 11, 2004 in Boulder, CO. Dr. Whiteman presents conceptual and practical information regarding winds in the planetary boundary layer in complex terrain. Part 1 topics include diurnal wind systems, mountain-plain wind systems, and slope wind systems. Part 2
topics include valley wind systems, cross-valley wind systems, diurnal
mountain wind systems, and plateau/basin wind systems.
Deformation Zone Analysis
is the next topic in Phil Chadwick's Dynamic Feature Identification series. The quick analysis of deformation zones provides an overview of system-relative atmospheric circulations. Since deformation is a primary factor in frontogenesis and frontolysis, understanding of these system-relative circulations is crucial to the diagnosis of atmospheric processes and weather prediction.
This topic builds on the previous two modules in the series, Vorticity Minima and Anticomma Patterns and Vorticity Maxima and Comma Patterns. Later this year we will be adding a module on the diagnosis of deformation zones.
Access http://meted.ucar.edu/norlat/sat_features/ to view french translations and OPMET Workshop materials in the Dynamic Feature Identification series.
Several new papers have been added to the NorLatMet Case Study Library this winter. Click the following links to read the abstracts and to link to the papers.
There are now 40 entries in the Case Library. Access to them is available at http://www.meted.ucar.edu/norlat/cases/
We've published another case exercise in the Mesoscale Aspects of Winter Weather Forecasting series:
Barrier Jet Forecasting: Eastern Foothills and High Plains of Colorado , 17-20 March 2003
This winter event produced historical snow amounts in the foothills of the Front Range of Colorado and very heavy snowfall along the urban corridor. The emphasis is on the role of the barrier jet, a core of low-level northerly winds that developed over and just east of the foothills due mostly to blocking and thermodynamic processes. The module consists of a Profile, Challenge, and Summary. We step through the storm, beginning early in the event, demonstrating the initiation and evolution of the barrier jet and presenting interactive questions as the storm progresses and finally dissipates. The emphasis is on both the dominant atmospheric processes and how the operational models analyzed and predicted the barrier jet and associated precipitation distribution.
The Dynamic Feature Identification series is now available in both English and French. We plan to release all future features in the series in both languages.
The MSC provided input on a Summer Severe Weather Distance Learning Course. This self-paced course discusses the basic principles of warm season convective weather with the aim of improving the prediction of significant and severe convection.
The course organizes relevant modules and Webcasts into two sections: Core Topics and Advanced Topics. By using our Registration & Assessment system, you can track your progress in one or both parts of the course and receive a course completion certificate.
COMET and the MSC team is pleased to announce the release of Dynamic Feature Identification: The Satellite Palette.
This new COMET series addresses the use of satellite imagery and focuses attention on the identification of
dynamic features using high-resolution satellite imagery with NWP verification. The series will eventually include more than 20 feature presentations on topics such as comma clouds, jet streaks, deformation zones, surface features, convection, and blocking. The first two to be published are "Vorticity Minima and Anticomma Patterns" and "Vorticity Maxima and Comma Patterns".
Each feature presentation includes interactive identification exercises, analysis and diagnosis, conceptual models, and forecast implications. It takes approximately 20 minutes to complete each feature in the series.
MSC/COMET Winter Weather Distance Learning Courses
In preparation for the upcoming winter forecasting season, the STT from each MSC and ADS office has compiled a selection of regionally relevant material from COMET's collection of winter weather content. These selections have been bundled together to create an online course for each office. To register and begin your course, visit the course site.
Two new titles have been added to the Mesoscale Aspects of Winter
Weather Forecasting series:
Precipitation Type Forecasting: New Brunswick, 01-03 February 2003
This interactive case exercise covers a 24-hour forecast period that includes the challenge of precipitation type forecasting. The case exercise provides an overview of precipitation type forecasting based on model algorithms, partial thickness analysis, and the top-down method. The module has 27 minutes of audio and will take approximately 90 minutes to complete.
Topics in Precipitation Type Forecasting
This module presents an overview of various aspects of precipitation type forecasting. It includes sections on microphysics and the ice crystal process, application of partial thickness analysis, application of the top-down method, and an overview of model algorithms used for precipitation type analysis. The contents of the module are accessible as a stand-alone piece or as content integrated into the New Brunswick, 01-03 February 2003 case exercise. As a stand-alone piece, this module will take approximately 30 minutes to complete.
Two more cases have been added to the NorLatMet Case Study Library this month:
Also of interest to the NorLatMet community is the recent COMET publication, Wave Life Cycle I: Generation. This is the second in a series of training modules on marine wind and waves. "Generation" examines how wind creates waves and the interrelationships between wind speed, wind duration, and fetch length during this process. Many marine forecast experts were consulted, including three from MSC: Ted McIldoon, Jaymie Gadal, and Ming Szeto.
While much of this instruction is at a basic level, all marine forecasters will find the more intermediate and advanced topics useful. One of these topics is the issue of dynamic or "trapped" fetch that often affects the offshore waters of Canada as tropical systems recurve along the U.S. East Coast. Extensive work with Peter J. Bowyer and Allan W. MacAfee of MSC went into creating this section which includes 3-D animations of dynamic fetch and an interactive version of Allan's dynamic fetch calculator. Additionally, the topic of scatterometry is discussed. Scatterometry is the observation of overwater wind direction and speed by polar-orbiting satellites using an active microwave technique.
User interactions are included throughout the module and within the short case study. The next module in the series will look at propagation and dispersion as the waves leave the generation area.
Fresh out of the bit bucket for those in need of a refresher on jet streak dynamics: Jet Streak Circulations. This Webcast is based on a presentation given by Dr. James T. Moore of Saint Louis University at the 5th Annual MSC/COMET Winter Weather Workshop on 30 November 2004 in Boulder, Colorado. Dr. Moore reviews many aspects of jet streak dynamics including convergence/divergence, vertical motion fields, ageostrophic winds, propagation, and coupled jets. The Webcast is 41 minutes in length and includes a quiz.
With the recent departure of Garry Toth and Peter Lewis from their 3-year assignment with COMET, we welcome their replacements. Phil Chadwick, MRB Toronto, and James Cummine, Prairies SPC Winnipeg, have joined us on a part-time basis for the next three years. They will be dividing their time between their current positions and COMET.
In addition to managing the next MSC/COMET Winter Weather Course (November/December 2005), they will be working on module development. Phil has already begun laying the foundation for a series of satellite feature identification tutorials while James has an Alberta Clipper case identified for use in our Winter Weather Forecasting series. Stay tuned
We've published a collection of material on lake and ocean effect snow: Topics in Lake Effect Snow Forecasting. This short module is a collection of narrated reference material on many aspects of lake effect snow forecasting. It is divided into three main topics: Basic Ingredients of Lake/Ocean Snow, Banding Processes, and Satellite Detection. These materials are also available as the separate Supporting Topics within the case exercise module, Ocean Effect Snow: New England Snow Storm, 14 January 1999.
We added a new case exercise to the Mesoscale Aspects of Winter Weather Forecasting series:
Blowing Snow: Baker Lake, Nunavut, Canada 04-10 February 2003. This case exercise takes an in-depth look at a blowing snow event in the northern mainland of Canada. The case addresses specific low-level wind and snow conditions. Model data, satellite imagery and observations are provided for assessing the potential for blowing snow and blizzard conditions as the event unfolds.
And don't forget the recent additions to the NorLatMet Case Study Library, including:
The Webcast, Dynamics and Microphysics of Cool-Season Orographic Storms, has been published. In this Webcast, Dr. James Steenburgh, working for the Department of Meteorology and the NOAA Cooperative Institute for Regional Prediction at the University of Utah, takes a look at cool-season orographic storms in western North America. He provides a brief microphysics review, an overview of cool-season orographic precipitation processes in several mountain ranges, and a look at forecasting tools and techniques.
The NorLatMet Case Study Library has recently been updated with a contribution by Serge Mainville, from CPI Montréal. An English and French version of his paper describes a forecasting tool for predicting heavy convective rainfall events over Québec.
A new version of the GEM regional NWP model became operational on 18 May 2004. Horizontal and vertical resolution have been increased, and many improvements have been made to the model physics. The Operational Models Matrix on the COMET MetEd Website has been updated to reflect the various changes. This site presents information about various NWP models, including GEM regional, in a single, convenient location. Check it out at: http://www.meted.ucar.edu/nwp/pcu2/launpcu2.htm
The NorLatMet Case Study Library welcomes the submission of case studies and research notes on any aspect of meteorology relating to latitudes poleward of 40ºN or 40ºS. This tool is designed to enhance scientific communication among the NorLatMet forecast community.
Polar Lows Ungava Bay Dec 2000
Polar lows are generally short lived but intense events that occur over cold ocean waters, poleward of a baroclinic zone. The polar low in this case formed over the open waters of Ungava Bay, in northeastern Canada on December 2, 2000. The case is presented as a series of challenging forecast questions followed by a more traditional case study presentation. Included in this exercise is a rich set of data products and access to background materials on polar low forecasting.
Topics in Polar Low Forecasting
This Webcast presents an overview of the climatology, formation, evolution, detection, and forecasting of polar lows. The presentation has five sections: Disturbances in Cold Air Masses; Climatology of Cold Air Vortices and Polar Lows; Monitoring and Nowcasting of Polar Lows; Polar Lows and NWP; Forecasting Process for Polar Lows. It also includes a printable forecasting checklist.
These products were developed through international collaboration with EUMETCAL, a European project aimed at promoting the use of computer-based training for meteorologists. As part of the effort, EUMETCAL developed a case exercise, The Mike Polar Low Case Study, tracking the evolution of a polar low in the Norwegian Sea on 05 Feb, 2001.
Another MSC Winter Weather Course presentation is now available as a Webcast: Inverted Troughs and their Associated Precipitation Regimes.
This Webcast features Phil Schumacher, NWS, Sioux Falls, South Dakota discussing the conditions that dictate the location of precipitation relative to inverted troughs. He presents a composite case study based on collaborative research with Dr. R. Weisman and others as well as two examples of inverted trough events in the central plains.
Accompanying Phil's Webcast is an online version of his lab exercise. The Inverted Trough Case Exercise follows the progression of a winter weather event across the central plains states beginning 1200 UTC on 7 March 1999. Each forecast question is accompanied by Eta model data and includes a forecast discussion.
From mm to cm... Study of snow/liquid water ratios in Quebec
In a detailed 130 page report, Ivan Dubé of the Meteorological Service of Canada reviews the factors that contribute to snow density, and presents a new and improved algorithm based on data from Québec for diagnosing and predicting snow density. A verification of the algorithm is included, along with a few case examples. This document is in English as a .pdf file. A previously published French version is also available.
The 10th and final piece in the series of Ten Common NWP Misconceptions is now online. This final section, entitled "Full Resolution Data are Always Required on Output Grids," investigates the misconception that valuable information is always lost by not seeing the model forecasts at their full native grid resolution.
The webcast, Heavy Banded Snow, based on a presentation by Dr. James T. Moore of Saint Louis University, has been released. In this webcast addresses the location of heavy banded snow in relationship to cold, warm and dry conveyor belts, the TROWAL, and equivalent potential vorticity. This webcast is based on a presentation by Dr. Moore MSC/COMET Winter Weather Workshop on 4 December, 2002 in Boulder, Colorado.
The 9th piece in the series of Ten Common NWP Misconceptions, "MOS Improves with Model Improvements", provides an overview of model output statistics (MOS) schemes. It details when MOS schemes are most likely to produce poor forecasts and lists advantages and disadvantages of MOS-derived output.
COMET is updating a series of Marine Meteorology modules with some Canadian input. The first release, Wave Types and Characteristics, is now available. It is an introduction to waves and their associated characteristics. Canadian tidal data was provided by Charles O’Reilly (Canadian Hydrographic Service / Tidal Analysis and Prediction) and a link to the CHS is included in the module. Both Jaymie Gadal (Thunder Bay Regional Weather Center) and Rob Kuhn (Ontario Storm Prediction Center) provided Great Lakes regional expertise and helped with the review of the seiche content. Ted McIldoon and Colleen Farrell also served as marine resource experts during the development of the module.
De mm à cm... Étude des rapports neige/eau liquide au Québec
In a detailed 130 page report, Ivan Dubé of the Meteorological Service of Canada reviews the factors that contribute to snow density, and presents a new and improved algorithm based on data from Québec for diagnosing and predicting snow density. A verification of the algorithm is included, along with a few case examples. This document is currently available in French as a .pdf file. The English version should be available later this summer.
NWP Models Directly Forecast Near-Surface Variables is the 8th misconception in the series Ten Common NWP Misconceptions. This piece discusses the details on how near-surface variables are calculated as well as potential sources of errors in their calculation.
The NorLatMet team has published the case exercise, Ocean Effect Snow: New England Snow Storm, 14 January 1999. This is the first in our newest series of modules: Mesoscale Aspects of Winter Weather Forecasting. The case is presented as a series of challenging forecast questions followed by a more traditional case study presentation. Included in the exercise is a rich set of data products and a series of background materials on lake/ocean effect snow and winter microphysics processes.
Radiation Effects are Well-Handled in the Absence of Clouds, the 7th in the series on Ten Common NWP Misconceptions, discusses the complexities of representing the balance of radiative absorption, reflection, scattering, and emission in an NWP model.
The Canadian Meteorological Centre's Global Environmental Multiscale (GEM) Regional Model is a short-range (0-48 hr) forecast model used operationally by the Meteorological Service of Canada and some National Weather Service field offices. It has just been added to the COMET Operational Models Matrix: Characteristics of Operational NWP Models. It is the first non-U.S. model to be included in the matrix.
The NorLatMet team releases, Freezing and Melting, Precipitation Type, and Numerical Weather Prediction. This Webcast is based on a COMET classroom presentation by Dr. Gary Lackmann at the 2nd MSC Winter Weather Course held in Boulder, Colorado on 22 February 2002. Dr. Lackmann reviews the basic thermodynamics of freezing and melting and how operational models represent these processes. It touches upon the biases that occur in the models by looking at examples of melting snow aloft, melting snow at the surface, freezing aloft (ice pellets), and freezing rain. Dr. Lackmann is a faculty member in the Department of Marine, Earth, and Atmospheric Sciences at North Carolina State University.
The 6th Misconception, A Good Synoptic Forecast Implies a Good Convective Forecast, in Ten Common NWP Misconceptions, has been published. This misconception reviews some of the details and biases on how NWP models use convective parameterization schemes. Issues of grid-scale, convective scheme tuning, and situations that lead to over- and underactive schemes are presented.
The COMET Program has released Isentropic Analysis, a Webcast, in which Dr. James T. Moore (St. Louis University) offers an introduction to isentropic analysis as a tool to diagnose and visualize vertical motion, depict 3-D advection of moisture, compute moisture stability flux, diagnose isentropic potential vorticity, diagnose dry static stability, diagnose conditional symmetric stability, and help depict 2-D frontogenetical and transverse jet streak circulations.
The 5th misconception, Convective Precipitation is Directly Parameterized, has been added to Ten Common NWP Misconceptions. It is the first of 2 misconceptions on how NWP models handle convection through convective parameterization schemes.
Slantwise Convection Case Exercise is released. This exercise examines a CSI event that took place in the 24-hour time period beginning at 18Z, 31 December 2000 in southern British Columbia, Canada. It accompanies the Webcast, Slantwise Convection: An Operational Approach.
The Canadian Meteorological Centre EPV Charts document is now available in French as well as English.
Le document L'instabilité conditionnelle symétrique (ICS) et les cartes de tourbillon potentiel équivalent (TPE) du Centre météorologique canadien est maintenant disponible en français autant qu'en anglais.
The 4th piece has been added to Ten Common NWP Misconceptions. The focus for this piece is on the handling of surface conditions in NWP models.
The Webcast, Slantwise Convection: An Operational Approach is released. This Webcast is based on a presentation by Kent Johnson during the 2002 COMET/MSC Winter Weather course. It focuses on assessing the release of conditional symmetric instability as slantwise convection. It provides an overview of the characteristics and theory of CSI, assessment of CSI and slantwise induced precipitation in complex terrain, and operational challenges to assessing CSI.
The NorLatMet team releases Diagnosing and Forecasting Extratropical Transition: A Case Exercise on Hurricane Michael. This exercise tracks Hurricane Michael as it moved into the Maritime region of the Canadian east coast in October, 2000. Analyze data and respond to questions focusing on forecasting the progression of the storm. This case exercise accompanies the Webcast, Hurricanes Canadian Style: Extratropical Transition.
The Northern-Latitude Meteorology Web site is launched!
A description of the new Canadian Meteorological Centre EPV Charts is published. The goal of the EPV chart is to aid operational forecasters in predicting CSI and slantwise convection. The description includes links to the online chart, which is updated twice daily by the CMC, as well as a list of synoptic considerations that will support your use of the EPV chart in identifying regions favorable for CSI and slantwise convection.
The Webcast, Hurricanes Canadian Style: Extratropical Transition, is published. This Webcast is based on a presentation by Jim Abraham and Peter Bowyer captured during the 2001 COMET/MSC Winter Weather course. It treats the difficult problem of forecasting tropical storms that transition and reintensify into extratropical cyclones as they move into the northern latitudes.
The first of Ten Common NWP Misconceptions is published. This module will be published over a period of several months. It introduces forecasters to ten commonly encountered misconceptions about NWP models. It will help dispel these misconceptions with information about how NWP is actually performed and how NWP products may be used intelligently. The content of Ten Common NWP Misconceptions is adapted from a COMET teletraining session delivered during 2001.
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