Aviation Weather Center (AWC) - Ceiling and = Visibility Articles

From: Subject: Aviation Weather Center (AWC) - Ceiling and Visibility Articles Date: Thu, 4 Jan 2007 08:55:12 -0800 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_000D_01C72FDE.0B4D9EF0" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C72FDE.0B4D9EF0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Location: http://aviationweather.gov/static/info/cigvis.html Aviation Weather Center (AWC) - Ceiling and = Visibility Articles 26 February 2002=20

Compendium of = Ceiling and=20 Visibility Articles for Operational Meteorology =
Last update: 26 February 2002

AVIATION WEATHER CENTER LIBRARY

Articles in the compendia listed on this web site have = been=20 pulled from numerous periodicals and textbooks resident at = the=20 Aviation Weather Center library. These articles represent = background=20 knowledge and continuing education for the forecasters to = gain a=20 better understanding of the weather hazards encountered by = aviators.=20 The articles are listed by the periodical, conference = preprints, or=20 texts, by year and title, and contain a short synopsis of = the=20 contents. By listing the articles in this manner they should = be easy=20 to find at your local library or university. If you are = visiting=20 Kansas City and would like to use the library, please set up an = appointment.

MAIN MENU - Compendium of Ceiling and Visibility = Articles

0. Backgrou= nd=20 Information
1. Periodicals=
2.=20 Conference = Preprints
3. Miscellaneo= us=20 Articles

Return to AWC = homepage=20

Aviation Weather Center, Kansas City, = Missouri

=20

0. Background Information

Ceiling and visibility are a major concern for air = traffic=20 decision makers. The forecasting of these elements directly = affects=20 the safety and efficiency of the National Air Space. A = measured=20 ceiling or visibility below certain values at St. Louis = Lambert=20 Field may have significant impact on arrival rates, while = the same=20 values at Dallas-Fort Worth or Boston's Logan Airport may = have no=20 impact at all. However, on a daily basis in the United = States,=20 adverse weather that causes prolonged, major delays at one = major hub=20 airport sooner or later will affect them all.=20

With this in mind, these ceiling and visibility articles = are=20 designed to give practicing meteorologists or those with an = interest=20 in aviation weather a practical background in these = phenomenon. The=20 articles date from 1950 to the present and contain a variety = of=20 rules of thumb, definitions, and examples.=20

The ceiling and visibility compendium is a follow-on to = the=20 turbulence and icing compendium released earlier this year = and=20 represent only what is on file at the AWC Library.=20

=20

1. Periodicals

Bulletin = of the American Meteorological Society
Weatherwis= e
Monthly=20 Weather Review
Journal=20 of Applied Meteorology
Weather=20 and Forecasting

Bulletin of = the American=20 Meteorological Society=20

	Objective Forecasting Studies, May 1952 A=20 'how-to' from Eastern Air Lines on undertaking = research=20 studies for operational forecasts. This is still valid = today=20 and gives the reader valuable insight in undertaking = local=20 studies. The paper begins with an example of ceiling = forecasts=20 in Atlanta.
	An Objective Aid to Local Forecasting, May=20 1952 Makes a case for the use of objective forecast = aids.=20 Suggests dividing the work on objectivity into four = classes=20 and follows the progress of a study from beginning to=20 completion.
	Forecasting the Lake Breeze and Its Effects on=20 Visibility at Chicago Midway Airport, March = 1954 A=20 study of air pollution in the Chicago area and the = problems=20 with forecasting visibility with its interaction with = the lake=20 breeze front. A suggested forecast procedure is = offered which=20 includes variables such as clear sky, light winds and = high=20 pressure.
	An Objective Method of Forecasting the Occurrence = of=20 Low Clouds in the McChord-Seattle Area During the = Summer=20 Months, March 1955 A local Air Force study of = cloud and=20 fog advection in the Pacific Northwest primarily using = pressure difference as an indicator.
	A Study of the Relationship Between Visibility = and=20 Temperature-Dewpoint Spread, January 1958 A = short paper=20 on this subject which equates the difference between=20 temperature and dewpoint and the occurrence of low = visibility=20 and fog. Several nomograms are presented.
	Mist - The Transition from Haze to Fog, June=20 1969 A study on the optical properties of haze and = fog and=20 how to determine which is obscuring visibility.
	Forecasting Local Weather by means of Model = Output=20 Statistics, October 1974 Explanation of how to = use MOS=20 as a predictor of several atmospheric variables = including=20 ceiling and visibility. The paper has several exhibits = explaining MOS results and skill.
	FOG-82: A Cooperative Field Study of Radiation = Fog,=20 July 1982 Scientists from 10 universities and = research=20 laboratories combined to describe parameters conducive = to=20 radiation fog formation. Research objectives include = studies=20 of fog mesoscale meteorology, radiation studies, = low-level=20 water budget, vertical fog structure, fog = supersaturation,=20 condensation nuclei, fog-water chemistry, and = radiation fog=20 life cycles.
	Synoptic Frontal Analysis: Time for a=20 Reassessment?, March 1991 Describes = deficiencies in the=20 Norwegian Model of frontal analysis and provides a = resolution=20 to bridge the gap between the old and new methods of = synoptic=20 analysis.
	Satellite Cloud Composite Climatologies: A New=20 High-Resolution Tool in Atmospheric Research and=20 Forecasting, March 1992 GOES digital imagery = has been=20 collected and processed using new techniques over = portions of=20 the United States since March 1988. High spatial and = temporal=20 resolution satellite cloud composite climatologies = (SCCC's)=20 have been produced that represent cloud frequency maps = for=20 each season. For each month studied, the cloud = composite=20 products represent the cloud occurrence frequency for = each=20 GOES pixel location and depict the overall spatial=20 distribution of cloud cover over large portions of the = United=20 States
	A Comparison of Ground and Satellite Observations = of=20 Cloud Cover, October 1993 An intercomparison of = several=20 systems including manual observations with = satellite-derived=20 products. An attempt is made to distinguish thin from = opaque=20 clouds. Errors in observational data are described = with=20 attempts to lessen them
	Fog on the U.S West Coast: A Review, February = 1994 Divides fog occurrences into four distinct = phases and=20 shows that periods of dense fog at west coast NWS = stations=20 fall within a 5 to 15 day sequence of synoptic=20 events

Weatherwise=20

	Boston's East Wind, June 1954 An = examination of=20 the sea-breeze front and its associated weather at = Logan=20 Airport. Includes some intrinsic characteristics of = the front=20 and its causes.
	A Steam Fog at Galveston, Texas, October = 1962 A=20 short study on the causes and characteristics of dense = fog=20 formation on the Texas Gulf due to cold air = overrunning.=20

Monthly = Weather=20 Review=20

	Forecasting Radiation Fog at Elkins, WV, May=20 1950 A study of the radiation fog at Elkins which = includes=20 the variables of gradient wind, surface temperature, = and=20 dewpoint depression. The period of the study is from = 1943 to=20 1949 and it empirically finds that clear nights with = easterly=20 winds favor radiation fog at this location.
	The Gulf Stream Front: A Cause of Stratus on the = Lower=20 Atlantic Coast, June 1950 This study attempts = to help=20 define the cause of stratus as a function of the Gulf = Stream=20 Front. Evidence from sequences of weather charts and=20 observations are presented as support to the = hypothesis of=20 frontal interaction with this phenomenon.
	On Forecasting Ceiling Lowering During Continuous = Rain, July 1951 The author contends that = ceiling=20 heights may be predicted with sufficient accuracy by = using a=20 set of empirically determined rules. He finds that = during=20 steady rain, the ceiling lowers in a discontinuous = fashion=20 depending on several ambient factors such as frontal = position,=20 near-ground turbulence, mixed intermittent heavy or = light=20 precipitation, and advection of cold or warm air. =
	Monthly Percentage Frequency of Ceilings 2000 = Feet or=20 Higher over the United States, September = 1959 One of=20 the first studies that links air traffic concerns = involving=20 delays or cancellations due to ceiling. This study is = a=20 climatology that intends to help forecasters by = providing some=20 advance guidance on the 2000 foot level. Maps of the=20 percentage frequency of occurrence of ceilings of 2000 = feet or=20 higher over the United States, excluding Alaska and = Hawaii. A=20 second set of maps shows for each month the change in=20 percentage from the preceding month.
	Forecasting Middle Cloudiness and Precipitation = Areas=20 by Numerical Methods, October 1959 A numerical=20 prediction model suitable for computation using = large-scale=20 digital computers to forecast amounts of middle = cloudiness,=20 areas of precipitation, and precipitation amounts is=20 presented. Along with the model is a nomogram for = determining=20 cloud categories such as partly cloudy and clear using = the 700=20 mb vertical velocity and dew point depression.
	Heavy Fog Regions in the Conterminous United=20 States, February 1969 Provides a geographic=20 distribution of fog within the CONUS and shows that = heavy fog=20 (visibility less than 1/4 mile) occurs more than 20 = days a=20 year at certain stations, of which 229 are air = terminals. The=20 distribution of fog is shown by conventional isopleth = analysis=20 and by fog climate regions with characteristic = frequency=20 distributions.
	Use of Model Output Statistics for Predicting = Ceiling=20 Height, December 1972 An examination of MOS and = how to=20 apply these statistics to ceiling forecasts. Several = case=20 studies are presented from data obtained over three = winter=20 seasons at 95 eastern U.S. stations. Prediction = equations are=20 developed for several levels and time periods.
	Monthly Fog Frequency in the Continental United=20 States, October 1973 Heavy fog (visibility = <1/4=20 mile) statistics for 244 first order stations were = used to=20 generate experimental objective analyses of the annual = and=20 monthly geographic distribution of heavy fog. The = resulting=20 computer-generated map of annual distribution was = compared=20 with existing analyses.
	The Summertime Stratus over the Offshore Waters = of=20 California, October 1977 A study over one = summer period=20 using satellite imagery to explain the formation, = movement,=20 and causative factors of summer stratus off the = California=20 coastline. The study discusses upwelling and upper = level=20 synoptic air patterns and their interactions.
	The Role of Inward Mixing in the Dissipation of = Fog and=20 Stratus, November 1978 A short article using = satellite=20 pictures offering a brief explanation for fog and = stratus area=20 dissipation. The article mentions that fog and stratus = will=20 erode from the outer edges inward.
	A Study of Visibility in Eighteen Cities in the = Western=20 and Southwestern United States, November = 1981 Airport=20 visibility data for the period 1958 to 1979 are = examined. The=20 data are statistically correlated to determine a = threshold=20 value below which the visibility is deemed poor. = Several=20 conclusions are drawn from the results including an = increase=20 in the visibility as a result of the 1971 Clear Air = Act.
	The Onshore Surge of Marine Air into the Pacific=20 Northwest: A Coastal Region of Complex Terrain, = December=20 1986 A detailed case study of a typical Pacific = Northwest=20 event as well as a composite of several events = regarding=20 marine surges and the strong winds, large temperature = drops,=20 and low ceilings that often accompany them. The study = shows=20 that all major surges are initiated by synoptic scale = changes=20 and that the mesoscale topography of the region = amplifies the=20 synoptic signal.
	The Diurnal Variation of a Marine Stratocumulus = Layer:=20 A Model Sensitivity Study, August 1989 A study=20 detailing the influence of shortwave radiative heating = during=20 different seasons on the decoupling of the cloud layer = from=20 the subcloud layer. Results for a typical winter and = summer=20 are presented. The paper shows that decoupling can = strongly=20 affect the surface energy balance
	The Relationship of Marine Stratus Clouds to Wind = and=20 Temperature Advection, November 1989 Compares = observed=20 cloud cover and satellite observations to model data = during=20 the FIRE exercise. The study shows that there is a = good=20 correlation between wind direction and temperature = advection=20 to marine stratocumulus coverage
	An Expert System Approach for Prediction of = Maritime=20 Visibility Obscuration, December 1989 Describes = the=20 AESOP system, an artificial intelligence approach to=20 forecasting maritime visibility obscurations. The = paper=20 describes the skill scores against random chance and=20 determines that this system can forecast fog events = correctly=20 75 percent of the time
	Diurnal Variation of Marine Stratocumulus over = San=20 Nicholas Island during July 1987, June = 1991 Explains=20 how marine stratocumulus behaves over a water surface=20 throughout the day which shows that cloud thickness = and liquid=20 water content decrease during the day and increase at = night=20 and provides statistical explanations for why this is. = San=20 Nicholas Island is 60 miles southwest of Los Angeles, = CA.
	Marine Stratocumulus Cloud Clearing Episodes = Observed=20 during FIRE, April 1992 An examination = including case=20 studies of marine boundary layer and reverse flow off = the=20 California coast which clears large areas of clouds. = The study=20 includes satellite pictures and several exhibits to = explain=20 these clearing events
	A Study of the Influence of Terrain on Fog=20 Development, September 1993 A general purpose = mesoscale=20 numerical weather prediction model is used to simulate = the=20 development of fog at Perth, Western Australia which = shows=20 that the uneven local terrain and the development of = local=20 nocturnal winds may frequently determine the location = and=20 timing of fog formation
	Cloud Cover and Its Relationship to Relative = Humidity=20 during a Springtime Midlatitude Cyclone, June = 1994 An=20 interesting study relating relative humidity as a = single=20 predictor of cloud cover and how this predictor = relates=20 vertically. Some conclusions show that when the air is = close=20 to saturation, current algorithms probably = underestimate cloud=20 coverage and that even small changes in relative = humidity can=20 result in large changes in cloud cover
	Numerical Forecasting of Radiation Fog. Part I:=20 Numerical Model and Sensitivity Tests, June=20 1994 Details a method to improve the forecasts of = radiation=20 fog events by using a one-dimensional model of the = nocturnal=20 boundary layer forced by the mesoscale fields provided = by a 3D=20 limited-area operational model
	Numerical Forecasting of Radiation Fog. Part II: = A=20 Comparison of Model Simulation with Several Observed = Fog=20 Events, June 1994 As in the first part of the = study,=20 only this part shows a correlation of observed vs. = model=20 forecast radiation fog events. It shows that the model = correctly reproduced the time of fog formation and its = vertical development when forcing terms derived from=20 observations were used

Journal of = Applied=20 Meteorology=20

	On the Forecasting of Winter Fog: A Geographic=20 Approach, June 1963 Examines an empirical = approach to=20 fog forecasting using streamline analysis and suggests = that=20 cool drier evening air represents more of a fog hazard = than=20 more saturated air. The study suggests that streamline = analysis produces higher skill scores than other = methods of=20 fog forecasting.
	Climatic Visibilities of the United States, = June=20 1966 Climatological visibility data for fifty-three = sites=20 is used to evolve seasonal visibility maps of the = United=20 States. The analysis is presented in the form of = cumulative=20 visibility frequency distribution maps. A brief = discussion of=20 their use and limitations to describe atmospheric = opacity is=20 included.
	Ozone and Visibility Reduction in the Midwest: = Evidence=20 for Large-Scale Transport, October 1977 Links = ozone=20 transportation over long distances to the incidences = of=20 photochemical smog over the Midwest during a five day = period=20 in the Summer of 1975. This study correlates ozone to = haze=20 with reduced visibility over a large region.
	The Formation of Marine Fog and the Development = of=20 Fog-Stratus Systems along the California Coast, = October=20 1979 This study summarizes the results of seven = field=20 expeditions aboard the Naval Postgraduate School's R/V = Acania,=20 designed to study the formation of marine fog along = the=20 California coast. The research yields four different = types of=20 fog and stratus and gives triggering mechanisms for = each.
	High Inversion Fog Episodes in Central = California,=20 August 1981 The meteorological conditions during a = fog=20 episode in central California during the winter are = described.=20 Results show that these types of inversions are = characterized=20 by uniform weather conditions with little variance. = Several=20 tables are shown.

Weather and=20 Forecasting=20

Fog Forecasting for the Southern Region: A = Conceptual=20 Model Approach, September 1997
A preliminary = attempt at=20 constructing a conceptual model is presented using = input from=20 several parameters including cloud condensation = nuclei,=20 moisture availability (saturation), and dynamic = forcing. An=20 illustration, and potential application, of how the = model=20 could be used is detailed

=20

2. Conference Preprints

1983=20 June
1992=20 March
1993=20 August
1994=20 January
1995=20 January
1996=20 August
1997=20 February
1999=20 January
2000=20 January, May, September, October
2002=20 February

19839^th = Conference on=20 Aerospace and Aeronautical Meteorology, June=20

	Forecasting Upslope Stratus and Fog in the = Central=20 Plains Outlines the synoptic patterns and = situations=20 associated with upslope fog and stratus and contains = two case=20 studies from which a routine is developed.
	Climatic Probabilities of the Vertical = Distribution of=20 Cloud Decks A study from the Air Force = Geophysical=20 Laboratory detailing the use of models to construct a = ceiling=20 climatology for Bedford, MA
	An Application of Statistics to the Determination = of=20 Visibility and Restrictions to Vision A paper=20 discussing a method of determining the weather or = obstruction=20 to vision and of deriving the sensor equivalent = visibility=20 (SEV). Visibility sensors using the measurement = principles of=20 forward scatter and backscatter are compares with each = other=20 and with a transmissometer

1992 Postprint Volume National = Weather=20 Service Aviation Workshop, March=20

	The Effects of Weather on Delays in the National=20 Airspace System Outlines the causes of weather = delays=20 in the national airspace. The article outlines the = operations=20 of the FAA ATCSCC, Center Weather Service Units, and = others,=20 in the decision making process whose chief functions = are to=20 minimize air traffic delays and to maintain = safety.
	The Impact of Terminal Forecasts on Fuel Load=20 Planning This article discusses Delta Airlines' = meteorology department and their requirements for = ceiling and=20 visibility forecasts for fuel load planning.
	Sea Fog and Stratus: A Major Aviation and Marine = Hazard=20 in the Northern Gulf of Mexico An examination = of fog=20 and stratus in this region. The purpose of this study = is to=20 develop techniques to help the forecaster identify = those=20 synoptic patterns which are conducive to the = development of=20 sea fog and stratus in the northern Gulf of Mexico. = Several=20 graphical aids are offered.
	The Effects of Summer Time Stratus at San = Francisco=20 International Airport on the Nationwide Flow of = Commercial=20 Airline Traffic A detailed examination of the = role of=20 low ceilings and visibilities at SFO and the effect on = nationwide air traffic decision making. Several = graphics are=20 offered. The roles of several entities involved in the = forecast process at SFO are detailed.
	An Objective Forecasting Aid for Summertime Low = Clouds=20 During San Francisco International Airport's Evening=20 Rush A detailed subset of the previous article = during=20 one time of the day at SFO. Several satellite pictures = are=20 included as well as tables and graphs which will = assist the=20 forecaster to better capture the low cloud heights = during the=20 evening in the summer.

1993 13^th Conference = on Weather=20 Analysis and Forecasting, August=20

Using the National Weather Service's NGM-Based=20 Statistical Guidance for Short-Range = Forecasting
A=20 study of the benefits and shortcomings of the NGM = statistical=20 model guidance. Establishes many constructive = guidelines for=20 its use.

5^th = Conference on=20 Aviation Weather Systems, August=20

	MEMFOG - The Memphis Fog Algorithm A = document=20 from Federal Express Meteorology studying an algorithm = for the=20 onset of fog at the Memphis International Airport. = Documents=20 fog frequency by length of time and time of night = including=20 the thresholds and limits of the study
	Analysis of Rapidly Developing Fog at the Kennedy = Space=20 Center An investigation of rapidly developing = fog=20 events that developed near the =91go-no go=92 decision = times for=20 the shuttle landing. Describes efforts to forecast = these=20 short-fuse events

199410^th = International=20 Conference on Interactive Information and Processing Systems = for=20 Meteorology, Oceanography amd Hydrology, January=20

"Meteo-Fuzzy" - An Expert System for Fog=20 Forecasting
A Romanian study describing the=20 construction of an expert system to aid in forecasting = fog=20 events using a mesonet = dataset

19956^th = Conference on=20 Aviation Weather Systems, January=20

	Use of NGM Regional Profile Forecasts for Fog=20 Forecasting for Space Shuttle Landing Operations at=20 KSC At study by the Spaceflight Meteorology = Group at=20 Johnson Space Center which details the use of the NGM = to=20 predict fog occurrence at Kennedy Space Center in = Florida in=20 order to provide the space shuttle the opportunity for = a=20 =91go-around=92 should fog be impacting the landing = site at KSC=20 (CCP 1993-4 C/V)
	The Accuracy of Ceiling and Visibility Forecasts=20 Produced by the National Weather = Service Verification=20 results of local ceiling and visibility forecasts are=20 presented for 90 stations within the contiguous United = States.=20 Verification scores are computed and the results=20 analyzed
	Characterizing the Causes of Low Ceiling and = Visibility=20 at U.S. Airports This study examines the = exposure of=20 U.S. airports that experience considerable delay (and = are=20 responsible for significant up- and downstream delay = at other=20 airports) to low ceiling and visibility conditions.=20 Frequencies of occurrence of these events are = tabulated and=20 correlated with IFR and IFR/VFR transitions as = relevant=20 measures of delay. The paper includes a decision logic = table=20 for characterizing IFR events.
	Short-Term High-Resolution Forecasting of Cloud = Ceiling=20 Heights and Visibilities Discusses short-term = forecasts=20 for less than two hours when compared to model and = persistence=20 forecasts. The paper shows that there is a need for = more=20 detailed and frequent weather information from both=20 observations and short-term numerical = guidance.
	A Hybrid Model for Predicting Fog and Stratus=20 Clouds A study by the U.S. Air Force and Saint = Louis=20 University describing a hybrid, analytical/numerical,=20 one-dimensional fog and stratus prediction model. It = shows=20 examples of model outputs, and describes an analysis = of model=20 forecasts of the onset of airmass fog. The paper goes = on to=20 describe future research in this = area

1996 15^th Conference = on Weather=20 Analysis and Forecasting, August=20

	Prediction of Ceilings and Visibility Using a = Regional=20 Scale Forecasting Model A study by Colorado = State=20 University outlining the use of the Regional = Atmospheric=20 Modeling System (RAMS) and how it=92s used to forecast = 36-hour=20 parameters such as cloud base height, fractional = cloudiness,=20 and visibility primarily for use by aviation = forecasters
	An Examination of the Mobile Bayway Fog=20 Disaster A post mortem examination of a = significant fog=20 event and a multi-vehicle chain reaction accident on = the=20 Mobile Bay. Several exhibits dissect the causes of the = fog and=20 provides hindsight observations of the NWS operations = during=20 the event.
	Screened GOES-8 Multispectral (10.7 micron - 3.9=20 micron) Satellite Imagery to Detect Stratus and Fog at = Night A study of the fog/stratus algorithm and = its=20 limitations and uses.
	Towards The improved Prediction of Regional Fog=20 Events Analyzes a different approach to = bracketing the=20 hazard that fog poses. Two approaches are offered: = traditional=20 and conceptual.
	Toward More Accurate Terminal Forecasts of = Stratus Burn=20 Off Times for the San Francisco International = Airport A=20 study of the impact of low stratus in the Bay Area and = efforts=20 to more accurately forecast stratus burn off to more = closely=20 match the peak demand times at the airport.
	Short-Term High-Resolution Forecasting of Cloud = Ceiling=20 Heights and Visibilities A paper showing = preliminary=20 results of a study to improve short-term forecasting = of cloud=20 ceiling heights and visibilities using the Penn = State/NCAR=20 mesoscale model MM5. The paper expresses the need for = more=20 detailed and frequent weather = information

19977^th = Conference on=20 Aviation, Range, and Aerospace Meteorology, February=20

	Cloud Layer Forecasting within the Local AWIPS = MOS=20 Program (LAMP) Describes the LAMP program in = detail and=20 how it can be used to forecast ceiling = heights
	Development of Algorithms to Objectively Forecast = Present Weather and Surface Visibility Using a = Regional=20 Numerical Model - An Update A study to = determine=20 statistical relationships between raw model output and = observed weather parameters in order to devise an = algorithm to=20 be used for the U.S. Air Force in its Theater Battle=20 Management Program
	Towards the Improved Prediction of Regional Fog=20 Events An investigative and operational = methodology is=20 described to improve the prediction of regional fog = formation,=20 distribution, intensity and duration
	User Sensitivity to Ceiling and Visibility and = its=20 Influence on Terminal Forecast = Verification This paper=20 describes the sensitivity for transport aviation users = of the=20 cost of inaccurate terminal forecasts and discusses = the=20 difficulties in verifying TAFs. A brief discussion is = given=20 showing that assumptions have to be made as to = forecast=20 interpretation before any verification scheme can be = derived.=20 Two algorithms are shown and conclusions are=20 offered.

19998^th = Conference on=20 Aviation, Range, and Aerospace Meteorology, January=20

Is the Meteogram a Forecaster's Tool for Fog and = Wind=20 at Vandenberg AFB, CA?
A report on the = viability of the=20 MM5 model to capture local wind and fog events. The = summary=20 includes two rules of thumb for MM5 = usage.

2000 2^nd Symposium on = Environmental Applications, January=20

Contributions to a Baseline Understanding of the = Impact=20 of Weather on Airline Carrier Operations
An = approach to=20 assessing the impact of various weather on airline = carriers by=20 treating the problem on a national scale. This study = compares=20 monthly data on carrier delays with a set of monthly = average=20 weather parameters (T/I)

16^th International Conference on = Interactive=20 Information and Processing Systems (IIPS) for Meteorology,=20 Oceanography and Hydrology, January=20

Forecasts of Strong Wind and In-Cloud Icing for = the=20 Danish Great Belt Bridge
A small-scale study on = the=20 effects of ice and wind on the Great Belt bridge using = simplified icing and wind models. This study has = applications=20 for low-level aviation as well

Ceilometer Comparison March 1998-April=20 1999
Compares the Vaisala CT12K Ceilometer and = human=20 observers over a one year period to determine the = accuracy of=20 the automated observation

NWS Western Region Aviation Workshop, May=20

Slide Presentations:

	Aviation Weather Hazards Awareness = Training
	Aviation Weather Center=20 Operations

9^th Conference on Aviation, Range, and = Aerospace=20 Meteorology, September=20

Forecast Aids to Lessen the Impact of Marine = Stratus on=20 San Francisco International Airport
A four year = study=20 into fog and stratus at SFO which has yielded several = forecast=20 algorithms that will aid the operational forecasting = of these=20 events toward the goal of mitigating delays they cause =

Steps to Improve Ceiling and Visibility Forecasts = for=20 Aviation
A white paper discussing the steps = necessary=20 to improve the NWS ceiling and visibility forecasts. = The goal=20 is to help the FAA reduce delays caused by over = pessimistic=20 forecasts

National Weather Association 25^th Annual=20 Meeting, October=20

Satellite Images Provide Valuable Information=20 Supplement to the Aviation Meteorologist
An = overview of=20 satellite imagery and its relationship to aviation = weather=20 forecasting in terms of turbulence and icing and = ceiling and=20 visibility. Excerpt From an ICAO Journal article=20 (T/I)

2002 18^th = International=20 Conference on Interactive Information and Processing Systems = (IIPS)=20 for Meteorology, Oceanography and Hydrology, February=20

The Use of Artificial Intelligence Methods in = Improved=20 Visibility Forecasts for Surface = Transportation
A study=20 undertaken by the National Highway Traffic Safety=20 Administration defining the use of artificial = intelligence to=20 forecast fog events to prevent surface accidents. Two = methods=20 are used - case-based reasoning, and rule-based = reasoning.=20 This has applications for the terminal aviation = environment.=20

Visibility Variability at the Chicago O=92Hare = Airport:=20 Insights into the Impacts of Runway Visual Range (RVR) = Measurements on Aviation Operations
Insights = into how=20 RVR factors into air traffic decision-making and how = the data=20 should prove valuable for traffic planning leading to = more=20 effective operations.

=20

3. Miscellaneous Articles

	ITWS Ceiling and Visibility Products, = 1994 A=20 study sponsored by the FAA outlining the products and=20 technical developments of the Integrated Terminal = Weather=20 System (ITWS) - a Doppler radar-based system for the=20 short-term forecasting in and around the airport = environment.=20 The ITWS system can be used to forecast short-term = ceiling and=20 visibility events as shown in this study
	Mesoscale Numerical Prediction of Ceilings, = Visibility,=20 and Turbulence, 1996 A contractor=92s report on = the=20 feasibility of producing a visibility, ceiling, and = turbulence=20 model prediction system. The study includes rationale = and=20 approaches to the problems inherent in numerical = weather=20 prediction in processing for these events
	Development of a Surface Visibility Algorithm for = Worldwide Use with Mesoscale Model Output,=20 1996 Categorized surface visibility equations with=20 empirical corrections have been developed for use in = limited=20 data environments with raw or mesoscale model out.=20 Verification results using a set of independently = collected=20 observations are presented

Return=20 to Information page
Return to AWC = Homepage=20

Aviation Weather Center, Kansas City,=20 = Missouri

------=_NextPart_000_000D_01C72FDE.0B4D9EF0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://aviationweather.gov/static/images/nceplogo.gif R0lGODlhywCCAOYAAB8aFysOcgNKlwBQnABTngBYowBapQBgqgBmrwBosQBttwBxvAB0vwB5xQB+ yACAygCFzQCK0QCN0gCU2AWZ3Qec3w6h4xmn5xus6yCt6yOu6yiv6yyv6zGw7Dax7Dmy7D6z7UC0 7US17Ue17Uq27k237lG47lO571e671u771688GK98GS+8Gi/8Wu/8W7B8XHC8XTD8njE8nrF8n7H 84DI84TJ84bK9IzM9JDN9JLO9ZbQ9ZnR9ZzS9qDU9qLV9qbX96nY963a96/b+LPd+Lfe+bng+b3h +cLCwcDi+sTk+sbl+svn+87p+9Pr+9bs/Nvv/ODx/OPy/ef0/ev2/e/4/vL5/v///wAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5 BAkAAFcALAAAAADLAIIAQAj+AK8IHEiwoMGDCBMqXMiwocOHECNKnEixYkUAGK8AGJhRI8aNHEGG tEhSpEaBGTd+TGnSI0eSMGMeBLnyJMqWB2PICMCT540bOHAEsEK0qNGiPXkaMdJTiVOeS6JGTRrg 6ZEjS3sSGSIk6Q+qPK0MPUo0qUKaNVHKXFtQZEecI6iiSKEiAIsWLVxQnUEjgA0bQJPy6NGDJ5Ag XZMuPZIkKZMATp5AgRKlsuXLUSY/cdLkMViwiQXvCJBjbNmkYsmqRhpg5kycMT+2NZmB5waeHjwE ABFCRNwAJUycQIEiKV4XL2D05Fvjr+nVq6mK5QmFp5QAVFBPD3A98+YAj6H+I/3hg3BPpM57xogB 40VPFitUpAgr/nRYngTfqoS9cGVagQFMQEEFPGGQgQYabMBBBwF48EEAvfFEQnDDzaXCCnfx5N56 MvBFX30gHhVAE04EINlkKD43HRMsLqFEY0sVUQQRYJVX2A465BDUDTzZUAMNM8iwnnIB4MWTfMTx VAIJI8RlVE8bIMjTBRZ82Fp+bnXk2ksANuDAAwFEIEEAA1pwgYE8Jbhgbh/wFkCTE/JEHF12HTeU f3h+hMSeSJCVJwB7+vnnSmTx+WdPhg6q6KEjiBACCB/kxmCUUoZ4xZVcGoTnQAEgwNMCDHj5AAQB SDABmRWYGcCBanbAppv/b44woXBJ3plnorfyedSfgVrxpxVI5BkAED/s+acOfAb755AvvKBXC/DJ lwJxJ5gQAJONhvBopFAimAEGKoIYQAFY/vcfTwcc4KkCoAbwZZimCpjqmbVpwNOaDvIWQqwTLuqv nroW9e9H0+2wg7L+IezfX8kq7F9S8anQMBJLNunotrp1wMEGlH7bEwUTnBqiWAOUq6VsBvFUgAHq JqBAAKCKCoGYAQ7Yk4EI3obvB7w2/KFRgyYbQIf+1mD00Uc7nOd67LUXgAvJ+hv1oh2DSyWBPEkQ AakONMDAAgsokICnBhRAQAAlz6ZlROMa0KmnMIfq7qgR0NyTmQayyvGC/gw62Ka2vv3Wkwm0EjdX CnRdiKF2SLnguONPPy755EbiZTkLmK8QMeLzGV6tCSWU8Nm2kXrQgca3efvt1RWAHGZPXXu9QABj I3BAT2mz1VAALfcUqsykjonqvPQGgGCCCp6em4O7gfDZmyRED1xwhJ9gvfWGG37eyNyLS5XqGFxw QQAVtD6BBFpDQCpPsoudAO8q6y4/p3E30BPdYpqalJln5n18ABxTEN9ctTzdPOh5nxFI9xbIwO08 4AEOCIDXkpKA+VlQfgjsSfksUCXx9S+DxwuhvUQownAt8GMUAIv6enLBFk4kJW1BCEvUcpIsocyF MkkLDG3CQ5doyoZr/sOhEGuyn0x5hD8OAWKWaGgTtNDEiDLMj9poiEQhWvGKI5HNW6TIpS3qRz9M 7CEWx0jGh6zNJE7ESUtU0kSUpdGIaFFLEMtIRzOucTYSSeBAGshAPTKEiDcBohjr+MIbzlEg86FK cjjkIcaRZViIEcIQiCAjpoCFRUxoAomcwMlOclKTmGSCi5KQBKxkEIHT6R5+XiPDQ17QlQbRzW4C ELieVCgAF2JBT9zDkw6ZEDoBCM1iesIisEhhCtipQgCqoEwqUAGZfQwCscrDExzpKCk/msHPTlMX 7q2yi24sCRcLQqDx6Q03uuGNb5RUOJ6soEh5WaROeNIcG/ySjyLq/8kUkLm9smxnlEfo53TIY54A 5EgofvFRAILELBe0ACypfGTGAGi8Kd2HlYNsJWx6IiZ5qUpvC2rQ33giq+DIiS4YOg4vY7CogAkK T4EaCk9CqSjoKO0jNuKBNXFw03+hoFoVa9RuPiAiDazul5fC401+uLZPyW1UpRJQAPCWgXM2KF+9 gZPoKmShsQwMYL0CWq7E+i/64OphU8uTkGIQgIml1T+OCkDpUOetbdYHU/4ZpJZ4hwCXBYAB7vrS zPSHNZzljANX/VvgShqAEwQgaA3rmUt9dSvK4qkoN+2BsYQV2TzBoD0OxQt8AjAtaoGOBD0RwVAl tTEpra5KJzSZE/59CKCV8cRlYAOsYKNKAZvR63jJy01SRPDVryarOY/9V1CWG5Se4glIQepsnuKD OLduVlhpMmr4LNA6120NTH+9j+3GxRMBvOQ/uyOAbWmnAHbJjSeDlde8wAVSyPIpdMLh6ofsKxYY KIpp6wGLcwHAk9Bazi6bm1Zx/YPYnryWQCBLHwQgaD+eiM12bjtb7i6Irr7iVoI8wd+Yeks8nCWF b8v7wN8i1CRZTYh6+dXe4RCnghqfUqZP4iNVWiyCizmvdKZDHaWScrXenq9uAaBw+3iC4QKYjZAF SUpuKwzf/AmoTB0EV1L2FtICqrhN+orQYlsMJ+ndE59oFg98J/4cwQn2xFMHgLLuPjNY4WmQg+LD gJ5X9TwFBYADA1ReAYU76OWdGc33QSAEzSLnMgKStgwBSwpP6UEPBqDSlT7zjVkoETdWsdGxiWMb P81DNsrxiOd94hrR2MUeuiVTRWziWbZI2xuCmoxaXOpSn3hqLa76iyGhdRsDGUhR3/rYryw2rGOI JSo6u9TBJjWyp90QX+sVjFQ09hF3eLJXD7vU+8kTqrdNbTl7O695jQmNNp2UIQwBJtzWVA3DWG6K eBvSj04IjyCqY/uc8DPA5PQfx2nremNU17C8Ql5u7D2eTJLdmARPKFvkIqoYoQjs5nfAMRXFjB7b XLEuiGNJm/9LqjCSBjXwi3R4Yp4fAOF5RmCMEoipycicCEU4f8JmQNmiF5kyg4TR6TYPHZ2h9IfX hNwhQZxH0lndkid3iScMAkxPgD9yOwEY5kw9YyKq7PPr+5RCZQQanSF4xQdUKc3zsA51opdl1lCU H7YHchsCHjBwTu9JLu3EE7baVc1jUQpjqFIiyvBkCtmhShWeKXbpAD7wAeiBTnPUk79kkyqh1eXf i55UZrtE2tUmN0HGl6bgypKWWrVWAOYSgMVpaOo6YY493X5XyATA8D1JvCN7whnwLEHTXwk6jgIQ lB4FAEhC0pBDE0121jxvfFZotucjonSBnGpefG6VcHmCd9H+rd5CKX3aSjuE8s2nuSxRSEr6A7B+ KwXg96WMUT97Uhie6IAnOLiB5ZHPE9AaKSk/pXpWIinZdTdj0XlhBHrBFmWlwhPYdyD3YnfcV2YU UispJXV+FzTiMShIUUw15wQ1tR3TwRSDYiOSNxo6kn9/MTClBVSo9SY/YxveEj4mxHHhlBBLJBC6 BSYdlUJ4Yzz2EgB2p05NwhOFA36ahxzKITWTRRQaqBr+ohrX9TDCd1YLthIVwxPbAhZGZX7RZ4Pj dHCXEjPv0oOpEgCG9WcEtBtZ5WIUonHGlSy7wisvtSj2MYWE0lZWuBLW9Vb+kS2QwlpDxj0IuCVI 9Cl/JTP/EVAz8wWBpscTRHgtFXg4XnUr9tUnZAVTmRiFRIGHH3EwfvgRa4Uo1kVgp2UxWyiIPOEx qjRwB8FX7xMzSRZfk0YvILWGRCg4wrF6KSBZnghWmOiEY2VZhCKMeOIDv0hg0uUfDRVarSctppWF QoVOqGM8VeWF0XF0tMUTLNNXLyNBgoVkHnUmQKgzQ9gb6zQrlxgol7iJAJMnrMErf8Ijy+gfjiNa miMfSXGKjeIoziOIHXNp3IWNrJE7aKRGnLJeCYBboRJBtFgmaKg3fsYTbQIhgXOFiiI0tvIvOdCR HpkDX5UUofgR0JKP01KK/kGAHBOE29U6ATImalY2aJNE/8bGjeoSAOySiOGoP+RDVcCFWCkGAhjJ hHxyfP/yF0iZlP8SJGsVA/W4EinQhwM2ZA8GMucTYl3zNWHzPrdjNgFgXtGmgJdyNt2Ik2ADjlBl hvyDJraxJr7IJ083h7nSK3YIIMsxA3i5KJ/VHs6yfHixhxhJKdrFE9wVYXXDZn8FNi8zXmYzABwn E23TEwzpJUmWNSEDkb+lAUEzgRRYPd93OCrAgdsxKAHwWUmxl3vpXJYDLfDxTtBILZ8zYCvxZ4K5 OkX2kt8FXoBFO2NzAG5TXi5kk944OzzxJXQTLz3pYBKJWASUL+q0WJJIPSP3GTWmOdvDE6sJT6v5 UD3xf/+Qx26gsyTY0o/NA2SnszFRsiq2WSU9MSYTRmFaSTtwk2FlBD/sNTsNCV6WOSAldo3IA2hU AWYWOWbREzrS2VjZkz2cwzmklUjnNzI9cXoyaFQewzoRlj5J1jU9ITa845sBQACgxmR+1RMyAy+m YjMWZViHhWKJBWaA02MtBj3R82IGSjjN96A4+kgBoD5g0gDtw6HcaHD0kxQ+6pBJcZnlM1X9U1Uh dBtgkWIqBgLOoy3o2GNj9hs5mqVlIWH6qZXf+JhCuhBUsVuWKVUbRBX+CVwCNEBXVWhf9qZypWI3 qqUBtzUTlhS7qQBhOj8IFDJXhjVJoWdVxSohZDwBtDf/GTenfeR8zxNB37SnLQR6z0NiCLRngjqo mKqemDqoBMl2VHEqfjRrCQepPwR3uRZro7o7ibqqFkFEXqRrpepx9XZH1YdRrDZuNYR0YhkbuxZO N3hGsGpIpPpHSDdvxuqKsjYSPvRo95ZvySp9cDdumwJpw8oW1XdvtbarkXqDyxZu1UpttIaq1nar tfZs6TZqRVSr37quR1dwOqRqccQSBceu9CqqM7SsUPSupsZruopw2lavBodeuepqvTp931auz8pq vvqvAHtFuSZ6ylqw9KY7acSvbOSt36atDYuD3catdySkMMRt+kqtGxt6xaarxeoQp9RHp0R9sPp5 o1ay/69Rq68GejmgA/fXGnQKoaeRTwLXHy97kBtrbQnIEOVndcDkqQg0czGYqOJBEIxGrM9GsgEb rieTEMmBGkirGlRBSZbUFMTEdeyWFWARBDxBTQEwGqRhfpfyqJ4nbHuKbaSmeVRBfvXkhasqcZq0 t3zLcz3nc58hBEIgTQR1gqSBUH4RIj+bRTj4cQTHH8XRehkST2CRcoBBfIy6qizygTrXuZ77SZ3R c6UUUKuKaG77snKksdYqhgPhfZHbnRg4T0kBFDhws88TSZOEcVSxBI9RcyeCGZehGZwRui4CuJ8x TVurqIDHsTpER1drEKo1OBUyH++0S7DnS1RRuyvXE/+SRElUwbQ8USI8YRlSUL7mK3aVoRlNCxpU UVD4d51W53any1SqC28twTz7knpJsXcL1xPY603dq7sBkARK8HtUMXYBwE9r503BJE30xwNJoYKz N3+O5z2slLIU+2kNhr894XS1gp39W8GKqxhaOyLqdx261xOLx0//lhSS1xM7kh5Dw1b24UggUohw lKr2VnAR2BO5+ILfh0srwJ2lSXU27E2NARbVcXhUUAWpkUorzH7eIb6KSx49obZJ4SNAkhTOghfU RXur9KizJatmJHomwZZqKFywUlK00hMXqBcBcHJ3q2MI1H44JiJiAQVPkBS/B3g5RRX6p1Dq4TQy xRP/pXVPLausOlxth8Set0iRP8wT01sX8KSEJ2d8D8pvSeFMifckPNEEvse00WHFATB5Kbhvx8dQ 7NGdo1UWJ1B0Wusx7AmtAiu1qOuD5hSE+MKGTfeGJLc4GMgTskd7dHwd5WvDPQF/V2FJIlK4Qod/ gfwjfcceXZwUifR3V5UUXXid0ErGokoQI3aG2RVcPdGGRjjJF9h/ctypLcx+6gcW4tsUM4cVFxcA ZvcZPGDKQhHNyBdgXVySSeGCRVjIQpgUtUEl9FGIISdtrsRbSroqOYNOFckvk4hSIIwcffe/WQoe CLTHOrppgztNQWdQp+wcQIJd0dKC1sIk4UKbMzhV/yoCprhKk1DLE+OYfXvjKnLlPN3XxigVdZbM ExkZjHXIh2XxGJurSSH4xCPYUzm1U0FxhdGILRAydC+djeA0ryfLgDx4ooAKUokViXGCzkAdAIvU UnIol5qYSj3BiUeRjAAgfMgC1wPDj9G7vjQITAsQhnMErF1ShoRFVW15jix2znNyIZXsHv+S1mrN h0QtMHZYKD1VGDoFmBjJ0j7GLXTVqQr9aeeqk1DFWw9oL6Z3d6k3nUKsecaI1mEF2TD12MS41GIB 15Jn2cA4kh/xJv44V4glJWBcQa2kbAxIhjsq2pdmWE6qG1jV099n0a692E0Y2wDT2Bwokj2lh5Yd JP/Y7VaDstvLs9nELBYzS2pONTcz04BlkplqCMltGBcV3U3SjRHOxdir7djuuNRw/ZQYocrK0Yd4 gor/aDqtZS9a5k0c63GdEov5ed6oItiHJYG0BD34FZeS9Zb3Ld/3Hd8AMB3JCIpw3ROgpYcpbVrA gS3eLYQNVlfhLdPMdkO3VT8O4JAdlZzIjWL4G72z0sbJNZc9Rd8aTpfw2FPFkoz6jRENZSQjHoCg Eyu7zROnA0BXHVvCLaYt8zJP9ZBKWuM6vdxa1RPE8Zbt+NwJo+FintvJyFO4Tc3/jDm4pNL8CInm uTHWmNdSHrFTfinq4o3ss5MN7sgRbXeKBSfAIRz/b9knYV7f7wiPndgzh1LkoJV5EfN9qI2KcSqI dYXQ4S3eRbttJtFhfgVYJerVeKNlAIQvXH4t/VLo+e1SC4YUPHBTPaV/RQ4AmScXjXVaJo4xDUJX 2kXqrgOhBhmGmUJeN+leVEaL8wXRCYJO+YJ6TTKUPB6MxWVQOIssxeUjs46PNRaV3I0RGCNcA14b AkkmoLpxPLFhqMvpCek2w/lUPKGWaKjl2/ec0O6LzhGSAjYwPwIkRd6aSOLff9Jgq6Jnt6k1Inwf GtbN2RZlBRAALHOfaLlCPJHemSlAfSOg9e6LfVEDA/MTHu/xA4OXMiAkuA0A0AjwedJaAy8+hXmV /+uTlWHTKR567holWzXNMjfJE/l5nGRCmBVfdym2jrCN6MC4UEeZlEkpmwDQlKtc8vLd7X+ykgRO JS0PXxnaPmPDjV4JljP9EDZZ7Hv+QOctX6qSJqWuPEJ/o5co1IrSEzTw9nD/9v4yJHz5LE5fXLVJ 6uSePmAC80Dq8Ft/4F7f8PDDkMXZ1X866kDY1oUeY5F74YAiNIsCFm078gN2Sitg2wMj9T2B0EbG 9zGemEyWLuNyNlwPmSvD7pNJmSbqUR8FXL6oVdJZHK+7469dFi9AmkyjHgDGUqSpnaz5jEhiOEqP J9mlXVRPIOcD+hW2lRj2m19pQcS+LlM2i+tDJv6+Jaia2So6jQQjlRQFaqNcNRcmrzhC/dgbriHN 8gJIYNbr//7vHyx6cY/bmTmb85k/9Tni+SZ/EmRQDhAaNGTAgOGChQoUKASQEAEChAABGjBYEEBB AgQHDBSIOODKR5AhRY4kSTIAxwMIEiiIyCCAAwcPIESQIGHCwogXMGTIIHDDBg4dAnjw8OEDiBAh RIgY0ZRERKgRUUxNUVWFigArVrBgYcWr1wAtxIoNO9bsWbIRubLQuuJq1RRTA6A4ETVi0xEBRCQF YZRohw4cfgYYSPAgQgoToEJ4AHPiApYYD5wMQKDkZcyZrwQwkFKlggUuX8qcaTMAhQoWLlyIqv5h Q4CgHYgWBYF0aV6nJEqUMGHixImpwe3atTLcOFioX5UvL27XxG4SJPCOWBoiQN/ZgAVvEBiAYFSF ExoGYOxgIkWWETVy9KjZ/fuPUD+zZNDAQcTSAW5WSL16Z/fXoJrNqNqsYwqv6HbrzTfg5goOBbhS uCoArCpUgTkMM9RQueH6GuqvwOzKIIDVEEpIvPEaM48i+TQyoDL4YoQvgJQioq++mGSCar/+dOKJ MNc4CGq24ZY6MLfdSgigt9+Ae/BJFBwMYEMqq8wwosAEE6gwgwIwMbGaHHrgpZYgSyCAjF60TEY2 36Pxs5YasE9HmiSISjWdvNvyJyFlIyoAAv+RUupA4wqNqMmIrFR00SsNjcjOqORE7yIaOWvzUhnR PHOB0CKKibw6b0LNAru2dA2oIT806ihBjcRtuugSTHJKRmu1tUryGJPoMciiwvTXNqMKzb77IgpV If5I1Ok/DYYDbDaiAkUqgEFvmw4vWm/V9lZjH2pMWEppBHbcSyPiNKoHZIoggqiSxbOgnvYMAFXA HC0wqaSMNDLRbfulMoB17eJVPnILBhYqOe0K9Sa7luWpu1PpffbPAVdltTaMr4voCn87Rs7bb+1K wGCSDbaLNHbB48+Cd4fbk88+A5gYWpo9+BBafj1W1FiHIoVKgZKDFnqziMY0tib9cIqo5Z3+HjbV UZkBkzpqqavOWefiFppAscUgsmtosMOOz1CFUEtNNePihfjln9p+zW24A+wYvK0hxc/oAMTWe++Q CuX6TjyXhde7H6EuVNtCkf6ab8ZJBuBxAGKE+myWDXcUg2wxTC4A/iqAGr7HQYq8cdIvC/30jyAv 17jOK7f86q+g8lxpqC6NXPUrIA8ds91Lt733zFC/PfXdRw87783ALj510ZcXXaThc/e9Td2NZ156 koy/Hffrc68e++lDwt1671Vfnvvnzx8d+PDfI1/47cmHfv31wd+++/ql15144s1nfv/vdU+A2ENd SYZnvfqxr32/05/30oc+8T3Qgfd7oPOC+hfB68VPg+KjIAQNCMDnDXCBQyseCO0XIwTST4D7w9// 6Jc/FB4wgfwb4fS0l0HtwbCG7isg+FYovx3uEIEh/J8LKWgwAPZOiSfkYAmD+EQeprCEFiwiEQmY PxjKL3rNEyEUvViwAuqQhRdcYvmIeLoOXvCLa/RdCq04RhWyEWwBAQA= ------=_NextPart_000_000D_01C72FDE.0B4D9EF0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://aviationweather.gov/static/images/bar.gif R0lGODdhcAAHAPcAAP//////zP//mf//Zv//M///AP/M///MzP/Mmf/MZv/MM//MAP+Z//+ZzP+Z mf+ZZv+ZM/+ZAP9m//9mzP9mmf9mZv9mM/9mAP8z//8zzP8zmf8zZv8zM/8zAP8A//8AzP8Amf8A Zv8AM/8AAMz//8z/zMz/mcz/Zsz/M8z/AMzM/8zMzMzMmczMZszMM8zMAMyZ/8yZzMyZmcyZZsyZ M8yZAMxm/8xmzMxmmcxmZsxmM8xmAMwz/8wzzMwzmcwzZswzM8wzAMwA/8wAzMwAmcwAZswAM8wA AJn//5n/zJn/mZn/Zpn/M5n/AJnM/5nMzJnMmZnMZpnMM5nMAJmZ/5mZzJmZmZmZZpmZM5mZAJlm /5lmzJlmmZlmZplmM5lmAJkz/5kzzJkzmZkzZpkzM5kzAJkA/5kAzJkAmZkAZpkAM5kAAGb//2b/ zGb/mWb/Zmb/M2b/AGbM/2bMzGbMmWbMZmbMM2bMAGaZ/2aZzGaZmWaZZmaZM2aZAGZm/2ZmzGZm mWZmZmZmM2ZmAGYz/2YzzGYzmWYzZmYzM2YzAGYA/2YAzGYAmWYAZmYAM2YAADP//zP/zDP/mTP/ ZjP/MzP/ADPM/zPMzDPMmTPMZjPMMzPMADOZ/zOZzDOZmTOZZjOZMzOZADNm/zNmzDNmmTNmZjNm MzNmADMz/zMzzDMzmTMzZjMzMzMzADMA/zMAzDMAmTMAZjMAMzMAAAD//wD/zAD/mQD/ZgD/MwD/ AADM/wDMzADMmQDMZgDMMwDMAACZ/wCZzACZmQCZZgCZMwCZAABm/wBmzABmmQBmZgBmMwBmAAAz /wAzzAAzmQAzZgAzMwAzAAAA/wAAzAAAmQAAZgAAM+4AAN0AALsAAKoAAIgAAHcAAFUAAEQAACIA ABEAAADuAADdAAC7AACqAACIAAB3AABVAABEAAAiAAARAAAA7gAA3QAAuwAAqgAAiAAAdwAAVQAA RAAAIgAAEe7u7t3d3bu7u6qqqoiIiHd3d1VVVURERCIiIhEREQAAACwAAAAAcAAHAAAI/wAB2KsH oGDBgQYPEkyIkOFCgw0hPlSYUOBEixUjUnSY8aJGjAZXHKgokuTIhCVRngy5smBKliZjqpQJc6bN mgZlLGTRpYvOgjx97uz5E0DQokeHCgVKVCnSpkyXGoU6VWrSqE+t9uySsIsXrga9gi0otutXs2MB lA17lm3atWTbxn0rV21duHbfkvFZsN5evgD8Eu37VwbhwYELHwYsmLHixIgbG4bsOPJjyYsn1/u6 wks+GV5ZdP4cejRoL6I9n05NGrXp0qpht2a9+rXr2Ldn26Ytu3ZsMisA3Ouy917B4cWPE+9iXPjy 5siZK0/unHp06M+nS6++/bp27NazcwMPHhAAOw== ------=_NextPart_000_000D_01C72FDE.0B4D9EF0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://aviationweather.gov/static/images/u-arrow.gif R0lGODdhDAAUAPcAAP///8yZZmYzAAAAAP////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////ywAAAAADAAUAAAIOAADCBxI UCCAgwgTKlzIsKHDhxAjSpzYUEAAhxYNLsw4UCFHggg/FgQgsuDFgyI3jvS4MmHKgwEBADs= ------=_NextPart_000_000D_01C72FDE.0B4D9EF0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://aviationweather.gov/static/images/arrow.gif R0lGODlhDAAUAPf/AP///8yZZmYzAAAAAP////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////ywAAAAADAAUAEAIPgADCBxI UCCAgwgTKhRQUGEAhRABMCQYsWJCihUZQpxY0CBCjh4BPLSIsGNIkg5RquS40eRBkC5fNlw4E0BA ADs= ------=_NextPart_000_000D_01C72FDE.0B4D9EF0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://aviationweather.gov/static/images/d-arrow.gif R0lGODdhDAAUAPcAAP///8yZZmYzAAAAAP////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////ywAAAAADAAUAAAIOQABCAxA kKAAgQgBFDSYcODCgw0XBoCoUKLEgxYLUsxI0aHGhh47RhQJsqTJkyhTqlzJsiXCjBIDAgA7 ------=_NextPart_000_000D_01C72FDE.0B4D9EF0--