METR 361
Spring, 2019
BUFKIT
A radiosonde sounding can be a very
valuable tool in many situations. As sounding
analyses can be time-consuming and difficult, especially under the deadline of
putting out forecasts and warnings, a computerized sounding analysis package
would be helpful. Fortunately,
forecasters at the Buffalo Weather Service Office have designed such a program,
mainly for analysis of lake effect situations.
BUFKIT, as the program is called, is also very useful during synoptic
snowstorms and severe weather situations.
It has been adopted by the NWS and is available free at the Warning
Decision Training Branch (http://wdtb.noaa.gov/tools/BUFKIT/ ).
Lab assignment:
1. Your professor will have BUFKIT running
on the computers in 308 when you arrive for lab. If you wish, you may install BUFKIT on your
personal laptop. Unfortunately, BUFKIT
won’t run on a Mac.
2. Familiarize yourself with the BUFKIT
screens in lab before continuing. The
main window is a sounding which is generated by a computer forecast, perhaps
NAM or GFS. BUFKIT supports many model types, like RAP, SREF, NAMm and, of course NAM and GFS (listed as nam and GFS3). For
practice today, we have a NAM profile on the screen. What you see is the
model’s forecast of the vertical properties of the atmosphere at one location.
You can choose that location, given that you have the BUFKIT profile for that
place. So, for example, in the top left
box, you could click on the green namm link and two
different cities show up next to the model box (KJFK and KPHX). If you click the RAP model, you get a message
that there are no RAP profiles since none have been downloaded for you. Click the nam link
again and switch to the EON nam profile. EON is Oneonta. An alumnus who is now the
Science and Operations Officer (SOO) at NWS-OKX has set up Oneonta BUFKIT
profiles for us. He lists them as EON.
Other BUFKIT profiles can be found at http://www.meteo.psu.edu/bufkit/CONUS_NAM_00.html and others on the web.
3. Once you have BUFKIT running and have
selected a model and station, you will see the initial time sounding. Click the
slider bar above the sounding to move from time to time manually. The time and
date are located at the bottom. You may
need to move the entire program window up to see it. Once you have clicked in
the slider bar, you can also advance the times using the keyboard left and right
arrow keys. NOTE: for some reason, time
advances to the left, unlike most other applications.
4.
Click the “Map” button to change the left-hand display. Notice there are several other choices (Data,
Indices, Precip type, Lapse rates, etc). Try them to
see what you get. Each display shows a
different aspect of the forecast sounding.
5. The sounding is drawn on a skew T – log
P diagram. You can add or subtract
features after clicking the Overlays button.
Try Dry Adiabats or click Clouds.
The sounding display will change. Click again to remove.
6. Add a display of vertical motion, i.e.,
Omega, also from Overlays. It’s a thin white curved line. Negative values show upward vertical motion
(do you know why?).
7. Click some of the other boxes and
notice what happens to the sounding. In
general, all buttons and boxes are toggles which allow you to design a sounding
which makes you comfortable with the information displayed.
Questions 8, 9, and 10 are the graded part
of this lab. Type your answers to a text
file. Put your name at the top and send
it to Jerome.Blechman@oneonta.edu
8. Based on the NAM BUFKIT
forecast for New York (KJFK), initialized at 00Z Sunday, February 1, 2015,
answer the following (Note, first check the box for Bourgouin
Precip Type):
a.
During what hour (UTC) and on what date is precipitation forecast to begin?
b.
What is the type of precipitation at the beginning, and to which types does it
change at which times to the end of the forecast period? Be sure to note from what precipitation type
to what other precipitation type. Do NOT
note intensity changes, so if 4 dot rain becomes 3 dot rain, don’t report
that. But if the rain becomes snow, you
must report the time when BUFKIT shows it.
c.
From the class website, download a text
file of observed conditions at KJFK. Time increases
from bottom to top in this list.
Contrast the predicted precipitation type to the observed values. As in
part b, do not report intensity but you must pay attention to timing. What can
you say about the BUFKIT precipitation type predictions?
d.
Turn on Omega at 12 UTC on Feb 2 if it is not already on. What does that display tell you about what’s
going on in the atmosphere at that time? Be quantitative in your answer. Include units. BUFKIT shows the numbers at the top, in
microbars/sec.
e.
A key meteorological event that you could see on a MSLP map of temperature,
fronts, etc. (if you had one) happens between 13 UTC and 15 UTC on Feb 2. What
is that event and what happens on the profile sounding to tell you what it
is? Cite two sounding features that are
useful in identifying that synoptic event.
f.
Just from the BUFKIT profiles, how much snow will fall and what is the total
liquid equivalent of the entire event?
Hint: you may have noticed this number in a previous screen. For snow, use an appropriate snow:liquid ratio to estimate how many inches and be sure
to report the value of the ratio you used.
9. Based on the NAM BUFKIT forecast for Philadelphia,
PA (KPHL), initialized at 12Z Saturday, January 12, 2019, answer the following
questions:
a.
This is a situation that is, in some respects similar to the KJFK events of
February 2015, shown in the KJFK BUFKIT profile from question 8. What probably happened in terms of Highs,
Lows, and fronts, based solely on the BUFKIT profile?
b.
What very important changes didn’t happen to the profile at KPHL in 2019
that did happen at KJFK in 2015?
c.
Based on the KPHL BUFKIT file, make a rough forecast of the most important
weather to occur in the following 48 hours (up to 12Z January 14).
10. One of the great advantages to BUFKIT
is that data may be generated for any point in the model, not just upper air
stations like KBUF, KOKX, and KALB. At http://www.meteo.psu.edu/bufkit/CONUS_NAM_00.html, with the NAM model
selected, pick Oneonta, which is EON. It’s from today’s 12Z NAM.
Analyze
the situation for the next 84 hours (12Z today through 00Z Sunday) for
Oneonta. You may also use the 12Z NAM
forecasts at the usual NCEP site using a browser (http://mag.ncep.noaa.gov/). Do NOT use any guidance other than
the 12Z NAM and BUFKIT profile. Analyze the corresponding BUFKIT forecast
from the perspective of the vertical atmospheric temperature, dew point, and
wind structure. You must report why and
how much (liquid equivalent) precipitation is forecast to fall at Oneonta
during the 84 hour period. Also, use the
BUFKIT forecast soundings to discuss the coming Arctic air incursion in central
New York.