Dan Dietz

Monday’s storms ended up being quite the severe weather outbreak. There were nearly 1400 reports of severe weather across the southeast quarter of the country. This is one of the most, if not the most, reports in a single day. This included 43 reports of tornadoes. For a graphic, go here.

Thursday is looking like another wonderful day. We’re looking at partly sunny skies most of the day. Highs in the mid to upper 60s for most, 70s down south. Clouds will move in ahead of a disturbance towards evening. Storms are expected to develop late in the evening along a stationary front parked across the state. These storms will move in overnight, bringing heavy rain to the area. Best place to find these storms tomorrow night will be north of I-70. Rainfall amounts of up to an inch are expected with some areas seeing more that get the heaviest concentration of storms. Given the lack of diurnal heating, I don’t imagine we’ll have much severe weather but we can’t rule a strong storm or two.

The stationary front is expected to drift south on Friday. Areas north of I-70 may be rather chilly on Friday with highs struggling to break 60. South of that front, well, you’ll be seeing temps near 80. Clouds will lingering during the morning hours, but I think they’ll start to pull out by evening. There may be several storms that pop early evening along that front – down in far southern Indiana. Much like Thursday night, I’m not expecting widespread severe, but I don’t think one can rule out a severe storm or two Friday night.

The front will start to drift north again on Saturday. A weak impulse may spark off some thunderstorms Saturday morning across central Indiana. Not expecting severe weather here. Clouds should clear by afternoon, bringing an awesome start to the weekend across the area. Expecting mid to upper 70s across much of the state with areas further south climbing into the 80s.

To finish off the weekend, I’m expecting an even warmer day on Sunday. Partly sunny across the board, with most areas seeing at least 80. Down south, mid 80s will be likely. Winds will also ramp up during Sunday afternoon. Details are still unclear, but a strong storm system will approach the area. This may end up being similar to Monday’s storm. Another severe weather outbreak is possible across the Midwest on Sunday. All the factors are there – instability, lift, and wind shear. Details are still to be worked out over the next several days, so I’ll attempt to keep you updated so stay tuned.

It looks like we’ll end the work week on a bit of a cloudy and drizzly state. A clipper system is moving south of Canada and into the region. It looks like pretty much everyone will get a chance of a few showers Friday afternoon and early evening. We’re looking at highs around 50.

To kick off the weekend we’ll have the state split on weather. The upper atmosphere will be disturbed over the northeast half of Indiana keeping clouds and sprinkles around. Highs there should be in the upper 40s. Areas west of I-65 and/or south of I-74 should get more sun than clouds and I expect highs in the low to mid 50s.

A warm front will lift north across the area in advance of a strong storm system developing over the Rockies on Sunday. This will bring another chance for showers during the day on Sunday. Temperatures will rise over 50 (over 60 further south) by evening and will continue to rise overnight.

Expect to start out your workweek in the 60s. We’ll have southerly flow at the surface with temps exceeding 70 by afternoon and dewpoints in the mid to upper 60s. This will set us up for the potential for severe weather Monday afternoon and evening. Strong to severe storms are expected to develop over Illinois during the afternoon and race across the state during the evening.

Now, this is several days out, so its not set in stone and details will change, but current model parameters suggest a substantial severe weather threat will develop on Monday. Models have had some consistency in showing this general threat over the past few days. I hesitate to get into too many details at this point, so I will keep an eye on this threat this weekend and keep you updated and fine tune things, so stay tuned!

Have a computer without a CD drive that you want install Ubuntu (or your favorite distro) on? Or, you’re like me and can’t keep track of CD’s to save your life. Then you might want to consider installing over your network using PXE installing. To do this you’ll need one other linux box on the network.

If you already have a linux box running a DHCP server you may want to use that machine. Otherwise, you’ll want to set up DHCP on the linux box you choose. On Ubuntu, you can install the package “dhcp3-server.” Be sure to disable the DHCP server on your router or things may get strange. Also, you will need to statically set the IP on this machine. I made this mistake by forgetting it was set to get it’s IP via DHCP… then rebooted the machine. Oops!

This will just be a quick guide to setting up DHCP, there are plenty of resources out there with more details.

The configuration file is in /etc/dhcp3/dhcpd.conf so open that in your favorite editor. Here is what I have mine:

default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.10.255;
option routers 192.168.10.1;
option domain-name-servers 8.8.8.8, 4.2.2.2;

subnet 192.168.10.0 netmask 255.255.255.0 {
range 192.168.10.100 192.168.10.200;
filename "pxelinux.0";
next-server 192.168.10.2;

}



Of course, tweak these bits to match your network. The only thing that is different from any old DHCP server setup here is the last two lines. “filename” tells the PXE booter what file to download off the tftp server (which we’ll set up shortly). next-server is somewhat optional if the pxe server will be on the DHCP server machine. Otherwise, point this to the PXE server.


Restart the DHCP server with

/etc/init.d/dhcp3-server restart

Next, you’ll want to install the package tftpd-hpa.


Make sure the tftp daemon is running by doing `service tftpd-hpa start`. By default, tftpd will serve the files in /var/lib/tftpboot but if you feel the need to change this the settings are in /etc/default/tftpd-hpa


Now, you’ll want to mount the ISO (or the CD) from the Ubuntu (or whatever) installer. The necessary netboot files will need to be copied.

cp -r /media/iso/install/netboot/* /var/lib/tftpboot/

These files will allow the PXE boot to load the Ubuntu loader. From here, it will need to access its repositories over http. So, we need to install the apache2 package.


Now, create some kind of directory structure on the web directory, such as

mkdir /var/www/ubuntu-10.04
cp -r /media/iso/* /var/www/ubuntu-10.04

We can now configure this install to be completely automatic and customized as you want. This can be done with a kickstart file. For now, we’ll leave this at the bare minimum and it will install like it would off a CD. Perhaps in a later blog post I can go into more details, but for now this’ll be good.


Create a file, ubuntu-10.04.ks in /var/www with these lines:

install
url --url http://192.168.10.2/ubuntu-10.04/

Of course, change that url to match your setup.


Now, we need to tell the PXE boot bits where to find this kickstart file. In the file

/var/lib/tftpboot/ubuntu-installer/amd64/boot-screens/text.cfg

The line in question is the append line. Should have something like,

label install
        menu label ^Install (from my http server)
        menu default
        kernel ubuntu-installer/i386/linux
        append ks=http://192.168.10.2/ubuntu-10.04.ks vga=normal initrd=ubuntu-installer/amd64/initrd.gz -- quiet

Now you should be able to boot off the network and get the Ubuntu installer as if you were booting off a CD.

We’re looking at another chilly night tonight – lows are expected to drop into the low 20s. Tomorrow should be much like today. A weak disturbance will keep clouds around and temps down. Weather will remain quiet until Saturday night when a slightly stronger disturbance moves in and will spawn precipitation across the area. Right now it looks like it will be cool enough for the precip to fall as snow or ice across some areas. Latest model runs bring the heaviest accumulations to areas south of I-70. Normally I wouldn’t get too gung-ho on snow accumulations with weak storms this late in the season, but it will be coming at night which will cut down on melting. I don’t really expect a lot from this system, probably no more than a couple inches. Things should improve towards the middle of week as temperatures rebound.

Before I get the recap we do have one ongoing cluster of strong storms to the west of Muncie. These are expected to remain sub-severe, however don’t rule out some hail and gusty winds with these storms.

Storms started rapidly developing across south-central Indiana early this afternoon just after 1pm exactly as I predicted this morning. These storms quickly went severe and warnings began to pop. There were also several tornado warnings, although as of this post no tornadoes were reported. There were several hail reports across southern and southeast Indiana. Largest I heard of was 1.25″ in Shelby county. Also a wind damage report or two. The storms continued to develop further as they moved into Kentucky and Ohio with numerous reports of hail and wind damage in southwest Ohio. All in all, we escaped the worst of the storms here in Indiana and it panned out mostly as expected. Decent start to the severe weather season.

Stay tuned for potential weekend snow and when the next severe threat will be!