Meteorology Commons^™

Tips From The Board Of Broadcast Meteorology For Gaining The Certified Broadcast Meteorologist (Cbm) Designation, Rob Eicher

Publications

These notes are intended to maximize the likelihood that you will pass the AMS CBM evaluation on your first attempt. Typically half of first-time applicants pass the evaluation.

Precipitation Modulation By The Saint Lawrence River Valley In Association With Transitioning Tropical Cyclones, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

The St. Lawrence River valley (SLRV) is an important orographic feature in eastern Canada that can affect surface wind patterns and contribute to locally higher amounts of precipitation. The impact of the SLRV on precipitation distributions associated with transitioning, or transitioned, tropical cyclones that approached the region is assessed. Such cases can result in heavy precipitation during the warm season, as during the transition of Hurricane Ike (2008). Thirty-eight tropical cyclones tracked within 500 km of the SLRV from 1979 to 2011. Utilizing the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR), 19 of the 38 cases …

Attempting To Turn Night Into Day; Development Of Visible Like Nighttime Satellite Images, Frederick R. Mosher

Applied Aviation Sciences - Daytona Beach

Visible satellite images have long been used in aviation flight planning. The visible satellite images show a variety of phenomena of interest to aviation, including fog, low clouds, thunderstorms, etc. Since one’s eyes detect visible light, the visible satellite image is easier for untrained personnel to interpret than other bands. The biggest problem with the visible images is that they are not available at night. However, other channels on the satellites can be used to develop a derived satellite product which looks very much like a visible satellite image. This derived product can then be inserted into the nighttime portions …

A Thermodynamic Analysis Of An Intense North American Arctic Air Mass, Jessica K. Turner, John Gyakum, Shawn M. Milrad

Publications

Northwestern Canada is a genesis region of arctic air masses often considered to be formed primarily through radiative processes. However, the details of their life cycle are poorly understood. This paper examines the formation, maintenance, and dissipation of an intense and long-lived arctic air mass, using a thermodynamic budget analysis.

The airmass formation is characterized by a deep-layer, multistage process that begins with snow falling into a nascent air mass. Radiative cooling from cloud tops begins the process. After the snow abates and clear skies are observed, the surface temperature drops rapidly, aided by the high emissivity of fresh snow …

Sensitivity Of Limiting Hurricane Intensity To Ocean Warmth, James B. Elsner, Sarah Strazzo, Jill C. Trepanier, Thomas H. Jagger

Publications

No abstract provided.

General Aviation Weather Encounter Case Studies, John M. Lanicci, Massoud Bazargan, Daniel Halperin, Scott Shappell, Jaclyn Baron, Rebecca Iden, Carla Hackworth, Kali Holcomb

School of Graduate Studies - Daytona Beach

This study presents a compilation of 24 cases involving general aviation (GA) pilots’ weather encounters over the continental U.S. The project team interviewed pilots who had experienced a weather encounter, and we examined their backgrounds, flight experience, and weather encounter details. Results from meteorological data analysis for each weather encounter were consistent with findings of larger GA weather accident studies in terms of the types of hazards encountered and flight phase during which the encounters occurred. Investigation of pilot weather products and the sources from which they were obtained revealed a lack of uniformity of pre-flight data sources and underutilization …

Synoptic-Scale Analysis Of Freezing Rain Events In Montreal, Quebec, Canada, Gina M. Ressler, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

Freezing rain is a major environmental hazard that is especially common along the St. Lawrence River valley (SLRV) in southern Quebec, Canada. For large cities such as Montreal, severe events can have a devastating effect on people, property, and commerce. In this study, a composite analysis of 46 long-duration events for the period 1979–2008 is presented to identify key synoptic-scale structures and precursors of Montreal freezing rain events. Based on the observed structures of the 500-hPa heights, these events are manually partitioned into three types—west, central, and east—depending on the location and tilt of the 500-hPa trough axis. West events …

Synoptic-Scale Environments Conducive To Orographic Impacts On Cold-Season Surface Wind Regimes At Montreal, Quebec, Alissa Razy, Shawn M. Milrad, Eyad H, Atallah, John R. Gyakum

Publications

Orographic wind channeling, defined as dynamically and thermally induced processes that force wind to blow along the axis of a valley, is a common occurrence along the St. Lawrence River Valley (SLRV) in Quebec, Canada, and produces substantial observed weather impacts at stations along the valley, including Montreal (CYUL). Cold-season observed north-northeast (n = 55) and south-southeast (n = 16) surface wind events at CYUL are identified from 1979 to 2002. The authors partition the north-northeast wind events into four groups using manual synoptic typing. Types A and D (“inland cyclone” and “northwestern cyclone”) are associated with strong lower-tropospheric geostrophic …

Revisiting 3d Stereo Satellite Image Displays, Frederick R. Mosher

Applied Aviation Sciences - Daytona Beach

Over 30 years ago, there were a number of development efforts to display 3D stereo satellite images and associated weather. Dr. Fritz Hasler showed how the GOES-east and west satellites could be remapped to generate true stereo pairs for obtaining cloud heights and he also showed how artificial stereo images could be generated using derived IR cloud heights to generate parallax shifts for the visible or infrared images. While there was a flurry of interest in the 1980s, the techniques had largely fallen from routine usage until recently. However, technology advances in both satellites and display technology has allowed for …

Disparities In Weather Education Across Professional Flight Baccalaureate Degree Programs, Thomas A. Guinn, Krista M. Rader, Thomas A. Guinn

Publications

The required meteorology coursework for 22 accredited professional flight baccalaureate degree programs was examined and compared. Significant differences were noted in both the number of required meteorology courses as well as the number of required meteorology credit hours. While all programs required at least one three-credit meteorology course, not all programs required an aviation-specific meteorology course. In addition to the required number of meteorology courses and credit hours, topics within the aviation-specific meteorology courses were also examined. The study showed the topics of “flight hazards” and “aviation weather reports and charts” were identified most frequently in course descriptions, followed third …

Global Satellite Images For Aviation Operations, Frederick R. Mosher, James Block

Applied Aviation Sciences - Daytona Beach

Flight planning and flight following dispatch operations require information on potential flight hazards. Hazards such as thunderstorms, turbulence, icing, fog, volcanic ash, etc., are potential problems which are not always forecast adequately by numerical models. Satellite images are used to monitor the weather conditions causing existing flight hazards, as well as being used to identify the development of new hazards.

A Diagnostic Examination Of The Eastern Ontario And Western Quebec Wintertime Convection Event Of 28 January 2010, Shawn M. Milrad, John R. Gyakum, Eyad H. Atallah, Jennifer F. Smith

Publications

The priority of an operational forecast center is to issue watches, warnings, and advisories to notify the public about the inherent risks and dangers of a particular event. Occasionally, events occur that do not meet advisory or warning criteria, but still have a substantial impact on human life and property. Short-lived snow bursts are a prime example of such a phenomenon. While these events are typically characterized by small snow accumulations, they often cause very low visibilities and rapidly deteriorating road conditions, both of which are a major hazard to motorists. On the afternoon of 28 January 2010, two such …

A Diagnostic Examination Of Consecutive Extreme Cool-Season Precipitation Events At St. John's, Newfoundland, In December 2008, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

St. John’s, Newfoundland, Canada (CYYT), is frequently affected by extreme precipitation events, particularly in the cool season (October–April). Previous work classified precipitation events at CYYT into categories by precipitation amount and a manual synoptic typing was performed on the 50 median extreme precipitation events, using two separate methods. Here, consecutive extreme precipitation events in December 2008 are analyzed. These events occurred over a 6-day period and produced over 125 mm of precipitation at CYYT. The first manual typing method, using a backward-trajectory analysis, results in both events being classified as “southwest,” which were previously defined as the majority of the …

Synoptic Typing Of Extreme Cool-Season Precipitation Events At St. John's, Newfoundland, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

Quantitative precipitation forecasting (QPF) continues to be a significant challenge in operational forecasting, particularly in regions susceptible to extreme precipitation events. St. John’s, Newfoundland, Canada (CYYT), is affected frequently by such events, particularly in the cool season (October–April).

The 50 median events in the extreme (>33.78 mm during a 48-h period) precipitation event category are selected for further analysis. A manual synoptic typing is performed on these 50 events, using two separate methodologies to partition events. The first method utilizes a Lagrangian backward air parcel trajectory analysis and the second method utilizes the evolution of dynamically relevant variables, including …

Analysis Of Causes Of Icing Conditions Which Contributed To The Crash Of Continental Flight 3407, Frederick R. Mosher, Debbie Schaum, Chris Herbster, Tom Guinn

Applied Aviation Sciences - Daytona Beach

On February 12, 2009, at 10:20 p.m. EST, Continental Connection Flight 3407 from Newark to Buffalo crashed 5 miles short of the runway at Buffalo, killing all 49 people on board and one person on the ground. The National Transportation Safety Board (NTSB) is still investigating the crash, but preliminary reports show the airplane was experiencing icing conditions before the crash. Preliminary reports indicate that the pilot did not respond properly to the icing conditions, which contributed to the crash. However, the presence of the icing conditions which were significant enough to cause aircraft problems needs further investigation to determine …

The New Aviation Meteorology Specialization In The Graduate Aeronautics Program At Embry-Riddle, John M. Lanicci, Erin A. Roberts

School of Graduate Studies - Daytona Beach

The next 12 months will be an exciting time of growth in graduate aviation studies at Embry-Riddle Aeronautical University's Daytona Beach, FL campus. Beginning in Fall Semester 2009, a new Area of Concentration (AOC) in Aviation Meteorology will be added to the Master of Science in Aeronautics (MSA) program, and the new Doctoral program in Aviation will be starting in January 2010. The Aviation Meteorology AOC adds a crucial specialty to the existing MSA options in Air Traffic Management, Aviation/Aerospace Education Technology, Aviation/Aerospace Management, Aviation/Aerospace Operations, and Aviation/Aerospace Safety Systems.

The Aviation Meteorology AOC is designed to be a cross-disciplinary …

Analysis And Modeling Of Ducted And Evanescent Gravity Waves Observed In The Hawaiian Airglow, D. B. Simkhada, J. B. Snively, M. J. Taylor, S. J. Franke

Publications

Short-period gravity waves of especially-small horizontal scale have been observed in the Maui, Hawaii airglow. Typical small-scale gravity wave events have been investigated, and intrinsic wave propagation characteristics have been calculated from simultaneous meteor radar wind measurements. Here we report specific cases where wave structure is significantly determined by the local wind structure, and where wave characteristics are consistent with ducted or evanescent waves throughout the mesopause region. Two of the documented events, exhibiting similar airglow signatures but dramatically different propagation conditions, are selected for simple numerical modeling case studies. First, a Doppler-ducted wave trapped within relatively weak wind flow …

Synoptic-Scale Characteristics And Precursors Of Cool-Season Precipitation Events At St. John's, Newfoundland, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

The issue of quantitative precipitation forecasting continues to be a significant challenge in operational forecasting, particularly in regions susceptible to frequent and extreme precipitation events. St. John’s, Newfoundland, Canada, is one location affected frequently by such events, particularly in the cool season (October–April). These events can include flooding rains, paralyzing snowfall, and damaging winds.

A precipitation climatology is developed at St. John’s for 1979–2005, based on discrete precipitation events occurring over a time period of up to 48 h. Threshold amounts for three categories of precipitation events (extreme, moderate, and light) are statistically derived and utilized to categorize such events. …

Dynamical And Precipitation Structures Of Poleward-Moving Tropical Cyclones In Eastern Canada, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

Tropical cyclones in the western North Atlantic basin are a persistent threat to human interests along the east coast of North America. Occurring mainly during the late summer and early autumn, these storms often cause strong winds and extreme rainfall and can have a large impact on the weather of eastern Canada. From 1979 to 2005, 40 named (by the National Hurricane Center) tropical cyclones tracked over eastern Canada. Based on the time tendency of the low-level (850–700 hPa) vorticity, the storms are partitioned into two groups: ‘‘intensifying’’ and ‘‘decaying.’’ The 16 intensifying and 12 decaying cases are then analyzed …

Global Composite Of Volcanic Ash “Split Window” Geostationary Satellite Images, Frederick R. Mosher

Applied Aviation Sciences - Daytona Beach

Volcanic ash is exceptionally hazardous for jet aircraft in flight. Flying through ash can quickly damage the jet engines, causing surging, flame out and immediate thrust loss. Pilots can inadvertently penetrate volcanic ash clouds because airborne weather radar will not reflect off the small ash particles, and the visual appearance of an ash cloud may look very similar to an ordinary meteorological cloud. To aid pilots in avoiding ash cloud areas, the International Airways Volcano Watch (IAVW) agreements have developed under the guidance of the International Civil Aviation Organization (ICAO).

Day/Night Visible Satellite Images, Frederick R. Mosher

Applied Aviation Sciences - Daytona Beach

Visible satellite images are very helpful for a wide variety of users. In particular, they are helpful in identifying areas of clouds and fog for general aviation pilots who must fly within sight of ground. However, visible satellite images have several major drawbacks, such as at night the visible pictures are black. Another problem is that it is sometimes difficult to distinguish between high clouds and low clouds. While the infrared channel can be used at night, frequently the low clouds and fog are near the temperature of the ground, so low clouds do not show up well on infrared …

Modification Of Precipitation By Coastal Orography In Storms Crossing Northern California, Curtis N. James, Robert A. Houze Jr.

Applied Aviation Sciences - Prescott

This study compiles and interprets three-dimensional Weather Surveillance Radar-1988 Doppler (WSR-88D) data during a 2.5-yr period and examines the typical orographic effects on precipitation mainly associated with winter storms passing over coastal northern California.The three-dimensional mean reflectivity patterns show echo structure that was generally stratiform from over the ocean to inland over the mountains. The flow above the 1-km level was strong enough to be unblocked by the terrain, and the mean echo pattern over land had certain characteristics normally associated with an unblocked cross-barrier flow, both on the broad scale of the windward slopes of the coastal mountains and …

Extratropical Transition Of Southwest Pacific Tropical Cyclones. Part Ii: Midlatitude Circulation Characteristics, Mark R. Sinclair

Applied Aviation Sciences - Prescott

This second of two papers on extratropical transition (ET) over the southwest Pacific Ocean focuses on the variability of ET. A climatology of ET onset based on a previously described objective technique shows that ET commences 158 of latitude nearer the equator on average than similar cases from the Northern Hemisphere. Characteristic midlatitude circulation patterns accompanying ET near 308S are identified by means of empirical orthogonal function (EOF) analysis of 50 storms. The first eigenvector pattern, explaining nearly half the circulation variability, expresses relaxed and enhanced pressure gradients south of the storm that define composites similar to ‘‘cradled’’ and ‘‘captured’’ …

The Extratropical Transition Of Tropical Cyclones: Forecast Challenges, Current Understanding, And Future Directions, Sarah C. Jones, Patrick A. Harr, Jim Abraham, Lance F. Bosart, Peter J. Bowyer, Jenni L. Evans, Deborah E. Hanley, Barry N. Hanstrum, Robert E. Hart, Francois Lalaurette, Mark R. Sinclair, Roger K. Smith, Chris Thorncroft

Applied Aviation Sciences - Prescott

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

Extratropical Transition Of Southwest Pacific Tropical Cyclones. Part I: Climatology And Mean Structure Changes, Mark R. Sinclair

Applied Aviation Sciences - Prescott

A database of tropical cyclone best track and intensity information for the southwest Pacific Ocean basin is used to construct a 28-year climatology for tropical cyclones that move into middle latitudes. Of the nine or so tropicalcyclones that form each year, an average of about three can be expected to migrate south of 35°S, with the greatest fraction in March. Storms entering the Tasman Sea west of New Zealand (NZ) move almost due south on average and retain greater intensity than those to the east of NZ, where storms decay quickly while moving rapidly away to the southeast. Storms east …

Simulations Of The Effects Of Water Vapor, Cloud Liquid Water, And Ice On Amsu Moisture Channel Brightness Temperatures, Bradley M. Muller, Henry E. Fuelberg, Xuwu Xiang

Publications

Radiative transfer simulations are performed to determine how water vapor and nonprecipitating cloud liquid water and ice particles within typical midlatitude atmospheres affect brightness temperatures T-B's of moisture sounding channels used in the Advanced Microwave Sounding Unit (AMSU) and AMSU-like instruments. The purpose is to promote a general understanding of passive top-of-atmosphere T-B's for window frequencies at 23.8, 89.0, and 157.0 GHz, and water vapor frequencies at 176.31, 180.31, and 182.31 GHz by documenting specific examples. This is accomplished through detailed analyses of T-B's for idealized atmospheres, mostly representing temperate conditions over land. Cloud effects are considered in terms of …

An Alternative Representation Of The Ice Canopy For Calculating Microwave Brightness Temperatures Over A Thunderstorm, Bradley M. Muller, Henry E. Fuelberg, Eric A. Smith

Publications

Passive microwave brightness temperatures (T(B)'s) at 92 and 183 GHz from an aircraft thunderstorm overflight are compared with values calculated from radar-derived hydrometeor profiles and a modified proximity sounding. Two methods for modeling particles in the ice canopy are contrasted. The first is a ''traditional'' approach employing Marshall-Palmer ice spheres. The second, or ''alternative,'' method partitions 20% of the ice water content into a Marshall-Palmer component for graupel and hail, and 80% into a modified gamma spherical particle size distribution function representing ice crystals.

Results from the alternative approach are superior to those from the traditional method in the anvil …

A Simulation And Diagnostic Study Of Water Vapor Image Dry Bands, Bradley M. Muller, Henry E. Fuelberg

Publications

A Limited Area Mesoscale Prediction System (LAMPS) model simulation and special 3-hour radiosonde dataset are used to investigate warm (dry) bands in 6,7 μm water vapor satellite imagery on 6–7 March 1982. The purpose is to reveal processes resulting in the formation and evolution of the dry features that appear as curving dark streaks in the imagery. Model soundings are input to a radiative transfer algorithm to generate synthetic 6.7 μm equivalent blackbody temperatures (TB) which are compared with those from the Visible infrared Spin Scan Radiometer Atmospheric Sounder aboard the Geostationary Operational Environmental Satellite. Simulated and radiosonde-derived vertical velocity …

Earth Observing System, Volume Iia: Data And Information System, Report Of The Eos Data Panel, Raymond Arvidson, Frederick Billingsley, Robert Chase, Pat Chavez Jr., Michael Devirian, Frederick Mosher, Et Al.

Publications

The purpose of this report is to provide NASA with a rationale and recommendations for planning, implementing, and operating an Earth Observing System data and information system that can evolve to meet the Earth Observing System's needs in the 1990s. The Earth Observing System (EOS), defined by the EOS Science and Mission Requirements Working Group, consists of a suite of instruments in low Earth orbit acquiring measurements of the Earth's atmosphere, surface, and interior; an information system to support scientific research; and a vigorous program of scientific research, stressing study of global-scale processes that shape and influence the Earth as …

The Frontal Hydraulic Head: A Micro-Α Scale (~1 Km) Triggering Mechanism For Mesoconvective Weather Systems, M. A. Shapiro, Tamara Hampel, Doris Rotzoll, F. Mosher

Publications

Measurements from the NOAA Boulder Atmospheric Observatory (BAO) 300 m tower, the National Center for Atmospheric Research (NCAR) Sabreliner aircraft, and the NOAA GOES-5 satellite, give evidence for the cross-front scale collapse of nonprecipitating surface cold-frontal zones to horizontal distances of ∼1 km or less. The leading edges of these frosts possess the characteristic structure of density current flows: an elevated hydraulic head followed by a turbulent wake. Vertical motions at the frontal heads exceed 5 m s−1 at 300 m (AGL). The ascent at the frontal head may act as a (∼1 km-scale) triggering mechanism for the release of …