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NATIONAL WEATHER SERVICE
TELETYPE ACCESS
The Rowan County Emergency Services has interfaced a telephone modem to the
National Weather Service's main Weather Teletype Line so that anyone with a PC
and a modem can access the System for real-time weather information direct from
the NWS State Headquarters in Raleigh or direct from any other National Weather
Service office, such as the National Hurricane Center in Miami, the National
Severe Storm Headquarters in Kansas City or the Tornado Forecast and Research
Center in Oklahoma City.
The NWS maintains a teletype circuit that goes to to their regional offices,
radio and television stations, local and state government emergency operation
centers and military bases throughout the state and Country. Through an Z-80
device manufactured by HAL Communications, Rowan County now has the
capability to allow anybody with a modem and a PC to monitor this circuit and
to pull weather information out of the HAL's memory. Once a person is into the
system, they can monitor the weather line in real-time or recall weather
information that may have come down the line previous to the access. There is
a 30K common buffer for previous forecasts, good for storing about 18 hours of
information, and a 4K priority buffer for emergency information, bulletins and
severe weather warnings and watches. The priority buffer ususally retains
information for about 48 hours. Both buffers are first-in, first-out.
The system is accessed by dialing 704-633-8024 at 1200 baud, 8 bits, even
parity and no stop bits. The system is completely menu driven, requires no
special knowledge, registration or password and is open to anyone.
The system is auto-answer on first ring and you will get a brief welcome
message and what is called the "Short Directory" when you first get into the
system. This short directory is a brief listing of the weather forecast
"products" that are resident in memory at that time.
The NWS is sending different information down the line almost all the time and
they refer to each different piece of information as a "product" The product
is uniquely identified in each message and the product code, when understood,
describes what the information, or broadcast, contains. The short directory
that greets a caller on sign-in tells what is in the two buffers. After the
short directory, the system prompts you with the time and date and a ">"
prompt. There is a help function and typing " H " (no quote marks" at the
prompt will give you a brief summary of commands. It is a very passive system
in that you can only retrieve information, not input or engage in an exchange
like you can this bulletin board.
To monitor the line and see what is being broadcast from the NWS, type an " M "
at the prompt. You will then go into the monitor mode and if the system is
active, will see some information. Keep in mind that the NWS now broadcasts in
the Baudot language at 75 baud so the monitor function will seem slow to you.
Also remember that the line is idle a good part of the time so you may see no
activity in the monitor mode. The exit the monitor mode, you can strike any
key and the ">" prompt will come back at you.
The funny-looking product names need some explanation. The short directory
will list about 25 or 30 files with names like RDULFPCLT 0114 or CLTCLICLT
2314, etc. The first three letters of the product name indicate where the
product came from, i.e., RDU indicates the broadcast originated at the
Raleigh/Durham Office of the NWS, CLT indicates the product came from
Charlotte, etc. There are too many origination codes to list here but you will
soon be able to recognize them when you see them. The second three letters in
the file name indicate what the product contains and again, there are hundreds
of different ones but the LFP indicates a "Local Forecast Product" and the CLI
means the "Climatological Report". Of particular interest is the LFP, the EFP
(Extended Forecast Product), the REC (Recreational Report) and especially the
SVS (Severe Storm), SVR (Severe Weather), TOR (Tornado) and TWO or TWI
(Tropical Weather Outlook or Information). The last two or three letters of
the product name indicate where the product is intended to go or the areas of
most interest for that product. NC means (of course) North Carolina and shows
that the product ending in NC is of interest or applicable state-wide. CLT,
GSO, AVL and RDU are self-explanitory. The four digits after the product name
is the time the product was recieved.
In summary, then, the product names you see in the short directory on sign-on
tell you where the product came from, what is in it and where it is intended to
be of the most interest, and the time it was sent from the Weather Service.
To recall a product (read a file) send an " R " at the ">" prompt (without
quotes) in either upper or lower case and, because it is an in-key routine, no
<ENTER> is needed. Another prompt will come back at you. You can then give
the product name in one of several ways. You can enter the whole product name
(RDUEFPNC), or the type of product (EFP) which will give you the most recent
product with that coding, or just the time (2135). A carriage return is
necessary here <ENTER> because product names can be either 8 or 9 characters.
When the product has been sent, you will get a date/time prompt ( 03-07-87
21:34 EST > ) and you are ready to read another product, to monitor the line or
to sign-off.
One exception to the above is the Zone Forecast ( RDUZFPNC ). It is broadcast
6 times per day and is broken down into 18 zones state-wide and is quite
lengthy, usually about 1800 bytes or about 1.5 minutes at 1200 baud. (Once you
start a product, there is no way to escape or abort). To see only the part of
the state you are interested in, you can specify, on the prompt line, which
area you want to see by giving the product name, a slant sign and the zone you
want, i. e. RDUZFPNC/NC07, which will return only the zone 7 forecast out of
the entire state forecast. The northern foothills of North Carolina is zone
NC07 and I can't begin to tell you where the other zones are or what they
cover. The NWS has a map I can try to get for people who are interested.
The NWS sends over 400 products per 24 hour period down the line. We are
saving only 27 of those and putting them into memory but they are the ones of
most interest to the Rowan County area and of importance to emergency
responders and planners. In the monitor mode, everything can be seen but only
27 of the products will go into memory for later recall. At present, we are
saving:
RDUEFPNC Extended Forecast, North Carolina
RDULFPCL Local Forecast, Charlotte Area
RDUZFPNC Zone Forecast, North Carolina
RDUSFPNC State Forecast, North Carolina
RDUSTPNC State Temperature and Precipitation