LAPB Publications, 1994
- ALBERS, S.C, J.A. McGINLEY, and D.L. BIRKENHEUER. LAPS Analysis of Clouds and
Precipitation. Preprints, Sixth Conference on Mesoscale Processes, Portland, OR, July 18-22,
1994. American Meteorological Society, Boston, 158-161 (1994).
- BIRKENHEUER, D. The positive impact of GOES-7 data in the LAPS Water Vapor
Analysis. Preprints, Seventh Conference on Satellite Meteorology and Oceanography,
Monterey, CA, June 6-10, 1994. American Meteorological Society, Boston, 400-403 (1994).
- BROWN, J.M., and E.J. SZOKE. Evaluation of model utility in predicting snowstorms in
eastern Colorado. Preprints, Tenth Conference on Numerical Weather Prediction, Portland,
OR, July 18-22, 1994. American Meteorological Society, Boston, 138-140 (1994).
- BROWN, J.M., and J.M. CRAM. Further investigation of upstream conditions leading to
Colorado Front Range windstorms.
Preprints, Sixth Conference on Mesoscale Processes,
Portland, OR, July 18-22, 1994. American Meteorological Society, Boston, 485-488 (1994).
- CRAM, J.M., and S.C. ALBERS. The use of meso-beta-scale analyzed cloud cover to
initialize a numerical model.
Preprints, Sixth Conference on Mesoscale Processes, Portland,
OR, July 18-22, 1994. American Meteorological Society, Boston, 130-133 (1994).
- CRAM, J.M., S.C. ALBERS, and J.S. SNOOK.
Four-dimensional data assimilation
experiments at NOAA/FSL using LAPS and RAMS. Preprints, Second RAMS User's
Workshop, Fort Collins, CO, February 15-17, 1994. Colorado State University Press, 47-50
- CRAM, J.M., J.S. SNOOK, and J. McGinley.
The impact of different scales and frequencies of boundary conditions
on the LAPS mesobeta scale modeling/4DDA system.
Preprints, Thirteenth Conference on Weather Analysis and Forecasing,
Vienna, VA, American Meteorological Society, Boston (1994).
- Grgoire, P.J., N. Chaumerliac, and E.C. NICKERSON. Impact of cloud dynamics on
tropospheric chemistry: advances in modeling the interactions between microphysical and
chemical processes. Journal of Atmospheric Chemistry 18:247-266 (1994).
A chemical module describing the tropospheric photochemistry of ozone precursors in both
gaseous and aqueous phases for a remote continental atmosphere has been developed within
the frame work of a two-dimensional cloud model. Dynamical, microphysical and chemical
processes are fully interacting in order to study the influence of clouds on ozone chemistry
and to quantify the relative importance of the different processes on the budget and evolution
of 12 chemical species. Whereas the concentrations of highly soluble species are strongly
affected by evaporation and sedimentation, less soluble species are affected primarily by
accretion. The model reproduces previously observed chemical phenomena such as the
enrichment of formic acid at the top of the cloud.
- HARTSOUGH, C.S., and J.M. CRAM. Assessment of satellite upgrades using RAMS.
Preprints, Second RAMS User's Workshop, Fort Collins, CO, February 15-17, 1994.
Colorado State University Press, 51-54 (1994).
- HARTSOUGH, C.S., and J.M. CRAM. Assessment of satellite upgrades using a mesoscale
modeling system. Preprints, Seventh Conference on Satellite Meteorology and Oceanography,
Monterey, CA, June 6-10, 1994. American Meteorological Society, Boston, 426-428 (1994).
- KELSCH, M. A prototype system for dissemination of important hydrometeorological
information to local decision-makers. Preprints, Fourth National Heavy Precipitation
Workshop, Scottsdale, AZ, September 12-16, 1994. NWS Western Region (1994).
- KELSCH, M. and P.A. STAMUS. Dissemination of local-scale weather information to
emergency preparedness agencies. Preprints, 17th Conference on Severe Local Storms, St.
Louis, MO, October 4-8, 1993. American Meteorological Society, Boston, 385-389 (1993).
- NICKERSON, E.C., and P. MCCASLIN. Airflow over the valley of Mexico: aircraft
observations during Project AGUILA. In Sixth National Meteorological Congress and the
Second Iberoamerican Congress on Atmospheric Environment, Mexico City, Mexico,
October 27-29, 1993. CIAMMA/93 Mexico City, 8 pp. (1993).
Measurements of meteorological quantities and pollutant concentrations in the air above
Mexico City were obtained during project AGUILA from an instrumented Beechcraft King
Air operated by the National Center for Atmospheric Research. The in situ winds obtained
for the level flight tracks of 500 m and 1100 m above the city reveal important details of the
terrain-induced modifications to the synoptic scale airflow patterns in the valley of Mexico.
Observations for the days of February 13 and February 19, 1991, are especially interesting
because on those days there was both a morning and an afternoon flight, thereby providing
information on the temporal evolution as well as the spatial distribution of the airflow above
the city. The data clearly show the effects of anabatic and catabatic flows associated with the
heating and cooling of the mountain slopes that surround the city on three sides, and which
play an important role in the resultant distribution of pollution over the valley.
- Renard, M., N. Chaumerliac, S. Cautenet, and E.C. NICKERSON. Tracer redistribution by
clouds in West Africa: numerical modeling for dry and wet seasons. Journal of Geophysical
Research 99:D6:12,873-12,883 (1994).
The vertical transport by clouds of an inert tracer and its redistribution by complex West
African circulations are examined using a two-dimensional mesoscale meteorological model
with explicit microphysics. The model reproduces the tropical distribution of clouds and
precipitation along a meridional cross section over West Africa, corresponding to the position
of the Intertropical Convergence Zone (ITCZ) during the dry and rainy seasons. The resulting
redistribution of the inert tracer is therefore closely related to the northward migration of the
ITCZ between January and July. The occurrence of biomass burning during the dry season is
shown to be an important source of tracer enrichment at upper levels in the atmosphere.
- SCHMIDT, J.M. The impact of the environmental wind shear profile on the simulated
structure of a severe bow echo squall line. Preprints, 17th Conference on Severe Local
Storms, St. Louis, MO, October 4-8, 1993. American Meteorological Society, Boston, 567-
- SCHMIDT, J.M., J.S. SNOOK, P.T. McCASLIN, and J.A. McGINLEY. Toward a nested,
local-scale operational forecast system using the CSU-RAMS. Preprints, Second RAMS
User's Workshop, Fort Collins, CO, February 15-17, 1994. Colorado State University Press,
- SNOOK, J.S. A nonhydrostatic mesoscale numerical modeling system structured for
operational use. Proceedings, The Life Cycles of Extratropical Cyclones, Vol. III, Bergen,
Norway, June 27-July 1, 1994. S. Gronas and M.A. Shapiro (eds.), Geophysical Institute,
University of Bergen, 364-369 (1994).
- SNOOK, J.S. An investigation of Colorado Front Range winter storms using a nonhydrostatic
mesoscale numerical model designed for operational use. NOAA TM ERL FSL-10, (573-
013/00037) 373 pp. (1994).
State-of-the-art data sources such as Doppler radar, automated surface observations, wind
profiler, digital satellite, and aircraft reports are for the first time providing the capability to
generate real-time, operational three-dimensional gridded datasets with sufficient spatial and
temporal resolutions to diagnose the structure and evolution of mesoscale systems. A
prototype data assimilation system of this type, called the Local Analysis and Prediction
System, is being developed at the National Oceanic and Atmospheric Administration's
Forecast Systems Laboratory. The investigation utilizes the three-dimensional LAPS analyses
for initialization of the full physics, nonhydrostatic Regional Atmospheric Modeling System
(RAMS) model developed at the Colorado State University to create a system capable of
generating operational mesoscale predictions. The LAPS/RAMS system structured for
operational use can add significant value to existing operational model output and can provide
an improved scientific understanding of mesoscale weather events. The results are presented
through two case study analyses, the 7 January 1992 Colorado Front Range blizzard and the
8-9 March 1992 eastern Colorado snow storm. Both cases are ideal for this investigation due
to the significant mesoscale variation observed in the precipitation and flow structure. The
case study results demonstrate the ability to successfully detect and predict mesoscale features
using a mesoscale numerical model initialized with high resolution (10 km horizontal grid
interval), nonhomogeneous data. Conceptual models of the two snow storms are developed
by utilizing the RAMS model output in combination with observations and other larger
domain model simulations. The strong influence of the Colorado topography on the resultant
flow is suggested by the generation of a lee vortex that frequently develops east of the Front
Range and south of the Cheyenne Ridge in stable, northwest synoptic flow. The lee vortex,
often called the "Longmont anticyclone," exhibits surface flow characteristics that are similar
to results from low Froude number flow around an isolated obstacle. A series of numerical
experiments using RAMS with idealized topography and horizontally homogeneous initial
conditions are presented to investigate typical low Froude number flow characteristics in the
vicinity of barriers representative of the Colorado topography. The results are compared to
the findings of previous investigations and to the case study observations and numerical
predictions. The findings suggest that the Colorado orography significantly altered the low-
level flow in both case studies resulting in mesoscale variation of observed precipitation.
Improved representation of the topography by the model led to the majority of the forecast
- SNOOK, J.S., and J.M. CRAM. Some results from the NOAA/FSL/LAPS real-time RAMS
runs. Preprints, Second RAMS User's Workshop, Fort Collins, CO, February 15-17, 1994.
Colorado State University Press, 59-62 (1994).
- SNOOK, and J.M. CRAM. The "p" in LAPS: a local-scale operational forecast system.
Preprints, Tenth Conference on Numerical Weather Prediction, Portland, OR, July 18-22,
1994. American Meteorological Society, Boston, 454-456 (1994).
- STAMUS, P.A., and M. KELSCH. Local-scale weather information for the fire weather
problem. In Proceedings of the 12th Fire and Forest Meteorology Conference, Jekyll Island,
GA, October 26-28, 1993. Society of American Foresters, 391-398 (1994).
Accurate and timely meteorological information is vitally important to the fire weather
forecasters and emergency managers who may have little meteorological expereince. National
Weather Service modernization is providing an increased amount of local weather data, and to
effectively present this information to forecasters the Local Analysis and Prediction System
(LAPS) has been developed. LAPS is designed to integrate all available weather data and
produce high-resolution analyses and forecasts in real time. These analyses are combined
with local information to create other forecasting aids, such as fire threat products. To
provide this information to users, a prototype PC-based system has been developed that
presents weather information in a format that is easily understandable to the nonmeteorologist.
The system allows the user to display radar images and other data, in addition to LAPS
analyses and fire products, with local geographic information such as road maps.
- SZOKE, E.J., and J.M. BROWN. Use of a mesoscale model for real-time forecasting in
STORM-FEST. Preprints, Sixth Conference on Mesoscale Processes, Portland, OR, July 18-
22, 1994. American Meteorological Society, Boston, 439-442 (1994).
- SZOKE, E.J., R. Glancy, and R. Wolf. Colorado supercell tornadoes: A set of null cases for
the Denver Cyclone. Preprints, 17th Conference on Severe Local Storms, St. Louis, MO,
October 4-8, 1993. American Meteorological Society, Boston, 252-256 (1993).
- Weaver, J.F., J.F.W. Purdom, and E.J. SZOKE. Some mesoscale aspects of the 6 June 1990
Limon, Colorado, tornado case. Weather and Forecasting 9:45-61 (1994).
During the late afternoon and early evening of 6 June 1990, a series of severe thunderstorms
produced nine tornadoes and numerous incidents of large hail on the High Plains of eastern
Colorado. While the morning synoptic data clearly indicated a severe threat over the entire
eastern half of the state, the severe activity that did occur was much more localized.
Significant events were confined to a relatively small geographical region east and southeast
of Denver, Colorado, including the small town of Limon, some 70 miles to its southeast.
Satellite, radar, surface, and upper-air data are combined to study some of the mesoscale
aspects of the severe storm environment. Results show that thunderstorm outflow from a
large mesoscale convective system in Kansas and Nebraska played a crucial role in focusing
the severe activity in eastern Colorado. Also, the evolution of convective development during
the early part of the day suggested presence of a sharp moisture gradient along the Front
Range of the Rocky Mountains, which further helped to localize the outbreak. Finally,
interactions between individual storms appear to have been critical to
severe storm evolution.
Copies of these papers may be obtained from the following sources:
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