Accessing Weather Information

The computers in the Atmospheric Sciences Department allow the user to access a wide range of weather information. Access can be achieved by using any workstation in the Department of Atmospheric Sciences which can be logged in as "maproom" or with the user's own login name.

An alternate method of accessing a variety of real-time weather products generated in this Department or at other locations is to gain Internet access by means of a World-Wide Web browser. This requires no special login permission, but it should be noted that the commands described in this manual will not be accessible by this method. See Section 7 of this document for more information on using a Web browser. This manual is organized as follows:

In the following text, commands will be shown in bold lettering and arguments will be in italics. The commands should be entered exactly as shown in lowercase letters. When specified, a command may require the following arguments:

Usually an argument of the form "yymmddhh" can be specified in abbreviated form. For example, if today is the 28th of January 2000 and you want to look at local observations at 18 GMT on the 25th of January, you need only enter "nw 2518" where the year and month default to their current values. The following arguments are all examples of valid specifications of the yymmddhh argument:

00012518 012518 2518 18

The omitted elements on the left side of each argument default to their current values.

If an argument is enclosed in brackets [ ] it is optional and omitting it will cause the command to use a default value which for the time is almost always the current or latest time.

Many commands require you to know a station ID. If you do not know the station ID use the command

stnid name

where name can be any keyword of the location you want. You will also find all the station and buoy IDs in a yellow binder located in the maproom.

When noted, a command may have a `man' (manual) page associated with it. A man page provides additional information about the command. It can be accessed by typing

man command

Also, by appending "-h" or "-help" to a command a "help screen" will often appear.

1.0 Surface Observations, Summaries, and Tables

1.1 North American Surface Observations

t stn undecoded time series for any aviation hourly station in North America. The command prompts you to input the start time, end time, and time interval (in hours). If nothing is entered at each prompt a default value is used. The defaults are: start is 18 hrs prior to the current time, end is the current time, interval is 1 hr.

td stn same as above but in decoded format for easier reading. Also this command will give the time series for CMAN stations and buoys, schoolnet and ecology stations.

tdd stn shortcut command for obtaining a decoded time series for the past 18 hours.

pacific [yymmddhh] this command gives an infrared image of the eastern Pacific Ocean and a surface map centered on the eastern Pacific

1.2 Pacific Northwest Surface Observations

To determine the names and IDs of Coast Guard observation stations, CMAN (Coastal Marine) stations, or buoys, refer to the yellow notebook in the maproom. Some of the coastal station IDs are four characters long and should be entered as four characters, not three. The command td stn (mentioned above) can be used if a decoded report at a coastal station or buoy is desired.

wacst most recent coastal observations from the Puget Sound area.

nw [yymmddhh] lists decoded station observations grouped by geographic sub-regions in WA, OR, and southwest BC. Only the minimum amount of date/time information need be given. (For example, if you want 21 UTC observations, type "21" in the time field and the most recent 21 UTC observations are displayed.)

spotters [stn] [yymmdd]

gives the NWS spotters reports submitted to the NWS Forecast Office stn on the day given. You may also do this with the lsr command (see section 2.1). The command spotters nw will give a summary of the latest spotters reports around the Pacific Northwest.

aws [yymmddhh] lists data from Automated Weather Source schoolnet sites in Washington and Oregon.

1.2.1 Cascades and Olympics

aval [yymmddhh] hourly reports for the 24 hours preceding the specified time from automated stations in the Cascade and Olympic Mountains. (Seasonal information, late November through April, mostly for locations in ski areas.)

hiway the most recent Cascade Mountains pass reports.

th [stn] time series of hydrometeorological reports from any station in the Cascades and Olympics. If the argument is omitted then a listing of all stations is produced. A listing of hydromet. station names is also in the maproom notebook.

hydro [dd] daily hydrometeorological reports from in the Cascades and Olympics (reports are SHEF encoded). A listing of station names is in the maproom notebook.

snotel stn gives the daily reports from automatic stations in the mountains. These observations include water equivalent of the snowpack (PILLOW) and the total amount of precipitation that has fallen since the start of the water year (Oct. 1).

wasnotel [yymmdd] gives the daily reports of all the snotel stations in Washington for the selected day.

orsnotel [yymmdd] same as above but for stations in Oregon.

1.2.2 UW Rooftop Observations

td uw will give in decoded format the hourly observations from the roof of the Atmospheric Sciences building. An hourly observation represents a ten-minute average for the period immediately preceding the top of the hour.

tuw gives a time series of observations from the roof with the option of selecting starting and ending time and time interval in minutes.

uwmin [dd] one-minute time series from sensors on the Atmospheric Sciences rooftop. To search for a specific time, at the `more' prompt, type "/hhmm" with a <return> to move to the data beginning at that time (GMT).

uwtail [#min] gives the last #min minutes of rooftop observations in one-minute increments. The default is 45 minutes.

uwpcp [yymmdd] gives the precipitation rate from the tipping bucket rain gauge atop the Atmospheric Sciences building.

uwdiurnal gives the warm season, sunny day composite of the diurnal cycle of temperature and winds from the top of the Atmospheric Sciences building. Days composited are listed by the command.

uwhr [dd] hourly time series and 24 hour summaries. The summaries are given at 00 and 12 UTC. The format of the output is as follows:

Hr, # of 1-minute Samples, Pmin, Pmax, Pmean, Tmin, Tmax, Tmean, Wdir, Wsp, Wgst, Precip, Solrad

uwplot gives a graphical presentation of the last 3 days of rooftop data.

solrad [yymm] daily solar radiation totals

uwst [hhmm] gives the rooftop observations at time hhmm for approximately the past 3 weeks.

1.2.3 Pressure Gradients

pd [dd] display the pressure differences between various sites in Washington and Oregon for the specified day.

pdgorge [dd] display the pressure differences between various sites located along the Columbia river gorge for the specified day.

1.3 Summaries and Tables

The following commands don't accept any arguments and give only the latest available report. Note that when current data is missing or not available, you will get the old information.

wasum summary of weather conditions across Washington.

watab latest max/min/precip table for Washington stations.

aktab latest max/min/precip table for Alaska stations.

ortab latest max/min/precip table for Oregon stations.

rnotab latest max/min/precip table for Nevada stations.

sfotab latest max/min/precip table for No. California stations.

laxtab latest max/min/precip table for So. California stations.

phxtab latest max/min/precip table for Arizona stations.

These commands do accept arguments as indicated:

table [xxx] [yymmdd] gives the max/min/precip table for stations in the vicinity of forecast office xxx for the day yymmdd.

records [yymmdd] gives a summary of record-breaking temperature and precitation events around the U.S. for the day in question

2.0 Forecasts

2.1 NWS Forecasts

The following commands give the most recent forecast issued by the Seattle NWS forecast office:

wazone most recent zone forecasts for the state of Washington.

wast most recent "state" forecasts for the state of Washington.

waxtnd most recent extended range forecasts for the state of Washington.

wadisc most recent technical discussion giving the reasoning behind the forecasts issued by the Seattle WSFO.

wamar most recent marine forecasts for Washington.

rainier most recent Mt. Rainier forecast.

xdisc gives a discussion of model performance along with national and regional extended forecasts.

The following five commands give forecasts from any forecast office in the United States and Canada.

zone zone forecasts for subregions within a state as well as extended forecasts.

disc forecaster discussions.

marine marine forecasts.

warn warnings for severe weather, avalanche and floods

lsr local weather spotter reports

For syntax information type any of the previous 5 commands followed by "-h".

wfo gives a list of NWS Forecast Offices around the U.S. with their 3-letter identifiers.

2.2 NMC Model Forecasts

ngmf stn [yymmddhh] gives 0-48 hour forecasts for city stn from the NGM model initialized on the day and hour specified by yymmddhh. If the time argument is omitted the most recent date and time are used.

etaf stn [yymmddhh] same as ngmf but for the ETA model.

ngmv stn [yymmddhh] gives the 12, 24, 36, and 48 hour NGM forecasts which are valid at the time specified by yymmddhh. The last line (TT=0) is the verification for the given day and time. This command is useful for comparing how the NGM model forecasts have evolved over the 48 hour period leading up to the verification time (yymmddhh).

etav stn [yymmddhh] same as ngmv but for ETA model.

The above commands produce output using the following abbreviations:

Notes:

- A negative temperature or LI is indicated by values greater than 50. To get the actual value, subtract 100 from the coded value. (Ex: A coded value of 97 would mean a true value of -3 (97-100 = -3).

- The yellow binder in the maproom defines more specifically what sigma levels "low, middle, and upper" refer to.

2.3 Statistical Guidance

nmos [stn] [ddhh] gives NGM Model Output Statistics (MOS) guidance for a given location (stn). When ddhh is omitted, the command gives the most recent forecast. See the maproom notebook for an explanation of terms.

mmos [stn] [dd] MRF MOS city forecast guidance out to eight days.

amos [stn] [ddhh] Aviation MOS guidance for the given city.

If stn is not specified for the above three MOS commands, Seattle (SEA) is selected by default. Also, the following command is specific to SEA:

seafcst [dd] Gives a daily summary of the MOS and NWS forecasts.

2.4 MM5 Numerical Forecasts for the Pacific Northwest

The NCAR/Penn State MM5 model has been adapted by the University of Washington for use as a mesoscale forecast model for the Pacific Northwest. Three different grid domains are used: 36 km, 12 km and 4 km. There are several commands to view graphical output from the modeling system. Typing the command with the "-help" option will display the syntax details for each command.

idtmm1 Views the graphical output on the 36 km domain using the NCAR graphics viewer idt.

idtmm2 Views the graphical output on the 12 km domain using the NCAR graphics viewer idt.

idtmm3 Views the graphical output on the 4 km domain using the NCAR graphics viewer idt.

lmm1 Animate time series of graphical output on the 36 km domain.

lmm2 Animate time series of graphical output on the 12 km domain.

lmm3 Animate time series of graphical output on the 4 km domain.

Information about idt can be obtained by entering "man idt". To display single frames of output the following commands may be used:

mm1 Views graphical output on the 36 km domain.

mm2 Views graphical output on the 12 km domain.

mm3 Views graphical output on the 4 km domain.

A time series of forecast surface data may be obtained with the following commands. stn is any of the regular surface station locations falling within the domain under consideration. [yymmddhh] is the initialization time of the desired model run.

tmm1 stn [yymmddhh] Displays hourly output form the 36 km domain.

tmm2 stn [yymmddhh] Displays hourly output form the 12 km domain.

tmm3 stn [yymmddhh] Displays hourly output form the 4 km domain.

The MM5 forecasts may also be accessed from the Atmospheric Sciences home page on the World Wide Web. Considerable additional information concerning the MM5 regional forecasting program can also be found on this Website.

3.0 Plots and Graphics

A large number of commands produce graphical output and require that the user be in an X-Window operating environment. For most plots pressing <return> with the mouse pointing in the window will remove the plot and return you to the prompt. Certain commands of a general nature may prove useful in dealing with the online real-time weather data:

wxloop will create a loop of gif images. Type wxloop -h for more information

path_request gives current location of the various types of real-time data

pattern_request gives the filename pattern information for real-time data

3.1 Surface Observations

map [location][parameter][yymmddhh]

A command to plot surface observations on a map which allows the user to choose the observation parameters, locations of the map, and the time of the plot. For example, to plot a surface map centered on Wenatchee at 18Z today type "map EAT 18". The word "print" appended to the command will generate hardcopy. Type "map -h" for more detailed information.

lmapw loop of the maps of surface obs. over western Washington for the past few days. (See section 8.2 for further information on loop control.)

lmape loop of the maps of surface obs. over eastern Washington for the past few days.

lmapps loop of the maps of surface obs. over the Puget Sound region for the past few days.

wxplot [-r] plots a map of station surface data over a specified region and time. The -r "research mode" option allows the user to customize the plot and make hardcopies.

mpps [yymmddhh] shows plotted surface map of Puget Sound region.

mpwa [yymmddhh] shows plotted surface map of state of Washington.

mppnw [yymmddhh] shows plotted surface map of Pacific Northwest region.

3.2 Upper Air Observations

Only certain stations send up radiosondes to collect upper air data. A listing of these stations is in the yellow maproom notebook.

sond stn [YYYYmmddhh] displays a sounding on a pseudo-adiabatic chart.

skewt stn [YYYYmmddhh] displays a sounding on a skew-T chart.

pirep stn [ddhh] pilot reports from airport stn for a six hour period beginning with the requested day and hour.

ua [stn] [yymmddhh] looks at a decoded sounding for requested station and time. Defaults are Quillayute at the latest time.

tua [level] [stn] views a time series of upper air data at the requested level and station. Defaults are 850 mb over Quillayute. The user is prompted for the beginning and ending time.

The following two commands plot two soundings on the same chart. One can either plot soundings of the same station at different times or different stations at the same time or different times. The first station is plotted in black, the second in red. All arguments must be provided.

msond stn1 YYYYmmddhh1 stn2 YYYYmmddhh2

mskewt stn1 YYYYmmddhh1 stn2 YYYYmmddhh2

By appending a "_prt" to the sond, skewt, msond and mskewt commands, output is also sent to your laser printer. E.g., "msond_prt UIL 2000011000 UIL 2000011012" will overlay the 00 and 12 GMT soundings at Quillayute on 10 January 2000 and send the output to the printer.

A list of sounding stations with their 3-letter identifiers can be displayed by typing the command "sondlocs".

3.3 Vertical Cross-Sections

These four commands require that your account be configured to operate GEMPAK commands. See Harry Edmon or David Warren for more information.

ngmsx [cxstns][gfunc][time][yaxis]

The default command (no arguments) creates a spatial cross-section based on the NGM gridded data at the most recent model initial time from a point over the Pacific Ocean (48,-155) to Wenatchee. Geostrophic wind vectors, relative humidity, and temperatures are plotted.

ngmtx [cxstns][gfunc][time][yaxis]

The default command produces a time cross-section analysis for SEA from the most recent NGM 0 to 48 hour forecast. Geostrophic wind vectors, relative humidity, and temperatures are plotted.

etasx [cxstns][gfunc][time][yaxis]

Eta version of ngmsx.

etatx [cxstns][gfunc][time][yaxis]

Eta version of ngmtx.

3.4 Lightning Data

These commands use data from the National Lightning Detection Network (NLDN) to display the lightning strikes. You will be prompted for desired day and hour. As mentioned in section 3.3, you must also be configured to operate GEMPAK to display the lightning data with these commands.

lt produces a map of lightning strikes over the United States.

ltnw produces a map of lightning strikes over the Pacific Northwest.

3.5 Seattle Profiler

The profiler is at the NOAA facility at Sand Point. The profiler makes use of Doppler radar to measure winds up to about 4 km, and sound wave propagation to measure virtual temperature up to about 1 km.

plotspt [yymmddhh] [time_interval] This command plots the soundings from the profiler, where yymmddhh is the ending time and time_interval is the number of hours between each sounding. Defaults are the latest hour for yymmddhh and 1 hour for time_interval. To remove the plot press return in the plot window.

Note: The following two commands require that the user be configured to use the GEMPAK software.

sp2c [yymmddhh] [NHRS] gives you a graphical display for the lowest 2 kilometers of time-height cross section of data from the profiler, NHRS is the number of hours contained in the cross section. This number must be larger than 3 in order for the command to work. The default setting is 24 hours of data ending at the current time. To quit type gpend in another window.

sp4c [yymmddhh] [NHRS] same as previous command, but the time-height cross-section of the lowest 4 kilometers.

spwt [yymmddhh] gives both the winds and temperatures at various heights for a 12 hour period ending at the time specified. The default ending time is the most recent hour.

spw [yymmddhh] gives only the winds at the same heights as the previous command for 12 hours ending at the specified time.

spt [yymmddhh] same as previous command but for virtual temperature.

tsp -l gives a listing of heights above sea level to choose from when using the command tsp.

tsp ht gives a time series of winds or virtual temperature at the height specified by ht. User will be prompted for beginning and ending times of time series.

tspt gives a time series of virtual temperatures for all heights. User will be prompted for beginning and ending times of time series.

4.0 Nexrad Weather Radar

These commands are for the WSR88D Nexrad Weather Radar installations at Camano Island, WA and Portland, OR. The most recent 5 days of radar images are maintained on disk. The raw data is routinely archived. For all commands the time argument is specified in UTC and defaults to the current time if not specified on the command line. The image closest to the selected time is displayed. Images of each type are normally available at 6-10 minute intervals. Images are stored as GIF files* in the directory /usr/local/ldm/images/nexrad and can be transferred to off-site computers supporting display of GIF files. Nexrad data less than 48 hours old may be accessed by University of Washington users only.

*GIF or Graphic Interchange Format is an industry accepted method of storing images in computer-usable form.

4.1 Radar Commands

Note: In the following commands ":mm" designates minutes after hour, hh. If the Portland radar is desired type "RTX" immediately after the command name and before other arguments. The option "-h" will give additional syntax information.

bref [yymmddhh:mm] [elevation_index]

Displays the base reflectivity at one of four elevation angles: 0.5, 1.5, 2.5, and 3.5 degrees (these correspond to elevation_index argument values of 1 to 4).

vel [yymmddhh:mm] [elevation_index]

Displays the field of radial velocity. Elevation angles are specified the same way as for the command bref.

lref [yymmddhh:mm] [elevation_index]

Displays layer maximum reflectivity at one of three vertical layers: 0-24, 24-33, and 33-60 kft (these correspond to elevation_index argument values of 1 to 3)

cref [yymmddhh:mm] Displays composite reflectivity averaged in the vertical.

tops [yymmddhh:mm] Displays echo top heights.

vil [yymmddhh:mm] Displays vertically integrated liquid water.

pre1 [yymmddhh:mm] Displays one hour precipitation ending at selected time.

pre3 [yymmddhh:mm] Displays three hour precipitation ending at selected time.

pret [yymmddhh:mm] Displays storm total precipitation accumulated up to the selected time.

The next set of commands allow the user to loop through a time series of radar images. These commands are analogous to the display commands above except they begin with the letter "l" which indicates they loop through a sequence of images determined by the time_specification argument. The time specification takes the form:

[yymmddhh:mm/time_length/time_step]

where yymmddhh:mm is the ending time for the loop which defaults to the current time if not specified. Time_length is the duration of the loop in hours while time_step is the interval of time in hours between images comprising the loop. If not specified time_length defaults to 2 hours while time_step defaults to 0.1 hr, which assures that all available images will be included in the loop.

lbref [time_specification] [elevation_index]

lvel [time_specification] [elevation_index]

llref [time_specification] [elevation_index]

lcref [time_specification]

lpre1 [time_specification]

lpre3 [time_specification]

lpret [time_specification]

ltops [time_specification]

lvil [time_specification]

Two additional TV station-operated radars are available:

kgw [yymmddhh] (near Portland)

king5 [yymmddhh] (near Sea-Tac Airport)

4.2 XAnim Documentation

The radar loop commands use the XAnim display program to loop through the radar GIF images. The following gives instructions on how to operate XAnim.

4.2.1 XAnim -Keyboard Commands

Once the animation is running there are various commands that can be entered into that animation window from the keyboard

q, Q quit

<space> Toggle. starts/stops animation.

, Single step back one frame.

. Single step forward one frame.

4.2.2 XAnim Mouse Button Commands

Once the animation is running the mouse buttons have the following functions.

<Left_Button> Single step back one frame.

<Middle_Button> Toggle. starts/stops animation.

<Right_Button> Single step forward one frame.

5.0 Graphical Weather Display Programs

A number of special programs for display of meteorological data is available on our system. The following can be launched by choosing "Additional Weather Data Display Tools" from the "Weather Data" item using the menu which appears when pressing the right mouse button.

ntrans Ntrans is a software package that displays the eta, meso-eta (for the Pacific Northwest only), ngm, aviation, and MRF model runs using graphics generated by gempak. With ntrans one can have two or more models displayed at one time. This makes comparing two models easier. Ntrans has more fields for the models than what is in the maproom. To get the ntrans selection screens, press the right mouse button once you are in ntrans.

garp garp is a display package designed by the COMET staff based on GEMPAK software and data formats.

mcidas McIDAS is a program which allows the user to display and loop satellite imagery, as well as surface, upperair and gridded data.

ive IVE is a software package designed to interactively display and analyze gridded data.

ntl launches a graphical menu with clickable icons for several display packages including ntrans and garp which are mentioned above.

6.0 Satellite Imagery

The following commands will bring up various types of satellite imagery and should be followed by a date/time group of the form [yymmddhh]. To dismiss the image type "q" with the mouse pointer in the window.

The sat commands are for the GOES East and GOES West satellites, where w is GOES West, e is GOES East, i for infrared, and v for visible. In the four single-frame displays below, you can pan the image by holding down the left mouse button and then moving the mouse.

satwi [yymmddhh] GOES West infrared image. If time is not specified, the most recent image is shown.

satwv [yymmddhh] same as above but for visible images.

satwiv [yymmddhh] loops (overlays) the infrared and visible GOES West images.

satei [yymmddhh] GOES East infrared image. If time is not specified, the most recent image is shown.

satev [yymmddhh] same as above but for visible images.

sateiv [yymmddhh] loops (overlays) the infrared and visible GOES East images.

Looping satellite images can be done with a set of commands structured as follows:

$loop$resolution$type$location$enhancement [options]

where:

variable choices meaning

$loop { "l", "" } loop, single-image

$resolution { "1km", "4km", "8km", "16km" } self-evident

$type { "ir", "vis", "wv", "fog" } self-evident

$location { "", "e" } GOES West, GOES East

$enhancement { "", "_nws", "_en" } Std, NWS, dept

Options are:

a time specification of the form:

[yymmddhh/duration/step]

where yymmddhh is the ending time for the loop which defaults to the current time if not specified. "duration" is the duration of the loop in hours while step is the interval of time in hours between images comprising the loop. If not specified, dration defaults to 6 hours while step defaults to 1 hr which assures that all available images will be included in the loop.

Also, -n $number will specify that $number images will be looped.

Here are some examples:

l8kmwve_nws -n 12

loop the 12 most recent GOES EAST NWS-enhanced 8km water vapor images.

l1kmvis -n 3

loop the 3 most recent GOES WEST 1km visible images

8kmire_en

display the most recent GOES EAST Dept-enhanced 8km IR image

Looping the 2 floater sectors can be done with the following commands:

lsatf1 [yymmddhh/duration/step]

lsatf2 [yymmddhh/duration/step]

The weather pull-down menus mentioned in Section 8 provide an alternative (and probably easier) method of looping satellite images. It should be noted that the pull-down menus generally permit display of only the most recent information.

7.0 Departmental Home Page

The Department of Atmospheric Sciences maintains a World Wide Web homepage accessible through the Internet with the URL (Uniform Resource Locater):

http://www.atmos.washington.edu/

To access real-time weather data use the link to "Weather Data and Forecasts". There are also numerous links to other types of information as well as to real-time weather sites at other institutions.

8.0 The Workstation Environment

8.1 Weather Information Using Pull-down Menus

Using the maproom terminals found in Room 627, you can use the mouse to obtain certain information using pull-down menus. Also, most student accounts are configured to use the pull-down menus. If you lack this option you can arrange with Harry Edmon or David Warren to have it implemented on your account. The following information is available using this technique:

- Local surface station plots

- Local soundings

- Loops

- Jetstream

- Forecast map

- Surface analysis/radar summary

- Recent visible and IR satellite images

Point the cursor in empty space, hold the right mouse button, and drag to your selection. If there is a menu icon at the right of the selection bar, drag the mouse to the right for more choices. Note that for many programs it takes several seconds or longer for any display or effect to occur.

8.2 Loop Control

With the mouse cursor pointing in the window, you can control certain loops with the mouse buttons:

middle Toggles loop mode on/off. When holding the <shift> key down and pressing this button, the loop is killed and you are returned to the prompt.

right When loop mode is off, pressing this button advances one frame in the loop sequence.

When loop mode is on, this button increases the loop speed. Holding the <shift> key down and pressing the right button will decrease the pause at the end of the loop.

left When loop mode is off, pressing this button moves back one frame.

When loop mode is on, this button decreases the loop speed. Holding the <shift> key down and pressing the left button will increase the pause at the end of the loop.