Well this is going to be dissapointing after all the "good" weather we have been having. (By good weather, I mean thunderstorms). Anyhow, it looks like the pattern has settled down for a while(....sigh).
We are currently under a ridge (500 mb) on both locations, which should lead to relatively sunny weather for some time. The current run of the GFS model, which can forecast out about 10 days, shows little action at 500 mb or the surface. There is really no action until we are about 6 days out on the model (in a realm known as "crystal ball realm." The models generally have trouble with accuracy that far out.). The precipitation that does pop up on the model appear to be a linear thunderstorm. However, models, such as the GFS, generally have trouble with thunderstorm (and you probably don't want the technical reasons).
So, overall, it looks like nice weather in both Alton and DeKalb. I guess we have to deliver the message of nice weather too.
Alton:
Tuesday: Sunny. Hi 77, Low 54.
Wednesday: Sunny. Hi 80, Low 58.
DeKalb:
Tuesday: Sunny. Hi 74, Low 53
Wednesday: Sunny. Hi 78, Low 55
Monday, May 18, 2009
Saturday, May 9, 2009
An Unintended Chase
May 7, 2009. What a great day! I was moving out of college and going home for the summer. During the drive south, we had to go through a SPC slight risk. We ended up leaving at a great time, and we saw some AMAZING weather! I was driving, so my dad took the following pictures.
This wall cloud was between Lincoln and Springfield, Illinois. We were driving 55 south looking west. This picture also has a very nice rain foot to the side of the wall cloud. A wall cloud is indicative of a strong updraft in the storm. If it is rotating, it is a prime place for tornado development. It doesn't garuntee a tornado. The rain foot shows the precipitation falling and spreading the rain cooled air on impact. It resembles a foot.
As we got south of Springfield, we noticed another wall cloud. We pulled off the side of the road to watch this one for a little while. This one actually was rotating. It was really cool to watch the clouds form right off the tip of the rain foot. Neither of these wall clouds produced a tornado, but they were cool to watch!
This is another view of the Springfield wall cloud. You can see the rain foot wrapping around the backside of the wall cloud in this picture.
Here is a video of the rotating wall cloud. It is a bit difficult to see on the video, but it was rotating very nicely. (We also had a lot more time to watch it, so it was easier to see it rotate.)
Here are some pictures of this impressive storm we were under. These were taken outside of Litchfield, IL looking north:
Later that night, a storm rolled through Alton, IL. There was actually a wind damage report, as one of the older buildings had a roof blown off. (SPC Reports). I was able to see some hail from my house and catch some lightning shots.
I like how you can see the hail falling in this picture. I wasn't even trying to get this picture of hail falling, but I caught it and am quite happy with it.
Just an idea of how much hail fell. Mostly pea-sized, but we had a few that were around 3/8 inch.
I tried to get some lightning, but it is hard to photograph. I did end up with some interesting lightning shots:
Well, that's all for this time. Hope you enjoyed it as much as I did!
Wednesday, April 22, 2009
April Snow Update
After all the panic, no snow fell in DeKalb. Tuesday saw a rather nasty day of mist to light rain conditions. According to the National Weather Service out of Romeoville, Illinois (the Chicago office), there was some pea-sized hail in the region.
Throughout the day Tuesday, I mostly walked in light rain. On my way back from my morning class, I did see some snow-like precipitation, but very little. I saw a few small flakes (probably about 5-10 in total), and a little frozen precip, but for the most part it was rain.
Conditions are currently sunny and warming. Currently it is 59 degrees, and temperatures in the low 80's could be seen Friday and Saturday. I am getting this straight from the National Weather Service today, as I am a little time crunched. However, we will be entering a 500 mb ridge, which should keep our weather nice. I'd better wrap this up, because I still have a lot to do before the end of the week. I'll get another post up as soon as I can.
Throughout the day Tuesday, I mostly walked in light rain. On my way back from my morning class, I did see some snow-like precipitation, but very little. I saw a few small flakes (probably about 5-10 in total), and a little frozen precip, but for the most part it was rain.
Conditions are currently sunny and warming. Currently it is 59 degrees, and temperatures in the low 80's could be seen Friday and Saturday. I am getting this straight from the National Weather Service today, as I am a little time crunched. However, we will be entering a 500 mb ridge, which should keep our weather nice. I'd better wrap this up, because I still have a lot to do before the end of the week. I'll get another post up as soon as I can.
Monday, April 20, 2009
S-S-S-Snow!!!! In Late April?!
This seems to be a fairly popular topic in DeKalb lately. There is a fair chance of seeing some late April snow. This has left some people panicking, however, it seems to really be nothing.
As always, let's get ready to do some map analysis! Current 500 mb maps show an upper level low parked on top of DeKalb. This is sitting in a pretty nice trough. A look at the surface map shows a low pressure located in northern Michigan. Now it is time to look at more features. At 850 mb, We can see a freezing line in central Illinois. This level is around 1250-1500 meters above the surface. If we were to look at another upper air tool, called a sounding, we can look at temperatures in a vertical profile. I am going to use the Davenport, Iowa sounding from 0000Z, which is the evening sounding.
I have added a thick blue horizontal line to indicate the freezing line. The vertical red line indicates temperature with height, and the vertical green line indicates dew point with height. Where they are close, the atmosphere is moist. This is a pretty moist profile, extending up to about 600 mb. So, most of the moisture is above the freezing line in this profile, indicating that if precipitation falls, it will fall frozen. Below the freezing line, it will more than likely melt.
So, what is going to cause the snow? It appears that the low in Michigan will be the problem. Motion around a low is counterclockwise. So, the precipitation forming around a mid-latitude cyclone will follow this motion. Areas north of the warm front are cooler, in this case cool enough for snow. The snow will follow the motion around the low, driving the snow and cool temperatures towards DeKalb.
As for accumulation, I don't think we will see any. Forecast soundings indicate that surface temperatures will not reach freezing. Both the GFS and NAM models are in fair agreeement that the nighttime lows will be around 36 degrees into Tuesday morning. Tuesday highs should be around 46, with Tuesday night/Wednesday morning lows being around 36 again. There is about a 70-80% chance of precipitation. We will also be having northerly , turning into westerly, surface winds around 15-20 miles per hour Tuesday, which will keep the air feeling cooler. With highs expected in the 40's, I would expect to see some rain as well.
To sum it all up, yes we may see snow in DeKalb. However, it will proabably have rain mixing in as the day progresses, and we probably won't have an accumulation. If we do end up with accumulation, it will be minimal, and probably won't last long.
As always, let's get ready to do some map analysis! Current 500 mb maps show an upper level low parked on top of DeKalb. This is sitting in a pretty nice trough. A look at the surface map shows a low pressure located in northern Michigan. Now it is time to look at more features. At 850 mb, We can see a freezing line in central Illinois. This level is around 1250-1500 meters above the surface. If we were to look at another upper air tool, called a sounding, we can look at temperatures in a vertical profile. I am going to use the Davenport, Iowa sounding from 0000Z, which is the evening sounding.
I have added a thick blue horizontal line to indicate the freezing line. The vertical red line indicates temperature with height, and the vertical green line indicates dew point with height. Where they are close, the atmosphere is moist. This is a pretty moist profile, extending up to about 600 mb. So, most of the moisture is above the freezing line in this profile, indicating that if precipitation falls, it will fall frozen. Below the freezing line, it will more than likely melt.So, what is going to cause the snow? It appears that the low in Michigan will be the problem. Motion around a low is counterclockwise. So, the precipitation forming around a mid-latitude cyclone will follow this motion. Areas north of the warm front are cooler, in this case cool enough for snow. The snow will follow the motion around the low, driving the snow and cool temperatures towards DeKalb.
As for accumulation, I don't think we will see any. Forecast soundings indicate that surface temperatures will not reach freezing. Both the GFS and NAM models are in fair agreeement that the nighttime lows will be around 36 degrees into Tuesday morning. Tuesday highs should be around 46, with Tuesday night/Wednesday morning lows being around 36 again. There is about a 70-80% chance of precipitation. We will also be having northerly , turning into westerly, surface winds around 15-20 miles per hour Tuesday, which will keep the air feeling cooler. With highs expected in the 40's, I would expect to see some rain as well.
To sum it all up, yes we may see snow in DeKalb. However, it will proabably have rain mixing in as the day progresses, and we probably won't have an accumulation. If we do end up with accumulation, it will be minimal, and probably won't last long.
Sunday, April 19, 2009
Update
I know I have not posted in a while (almost a month). School has really kept me busy these past couple of weeks, and the next two to three weeks look pretty full, especially with the semester ending. It may be a little while more before I can post a forecast. I really want to do another forecast discussion, but time is not on my side right now. With any luck, a time slot may open for a forecast discussion. Thanks for the patience.
Sunday, March 29, 2009
Storm Video/Pictures
Wow. It has been a while since my last post. Since then, there has been some pretty crazy weather. Here is some video and pictures to enjoy.
The first is from March 9. This was the day before the "Man vs. Machine" contest. I was on spring break, and what a way to start it with some severe weather. There was a tornadic storm roughly twenty miles northwest of Alton, IL. Here are the SPC Storm Reports from that day. From my house, I was standing in the inflow. It was relatively calm, and then strong sustained winds blew in the direction of the storm. I have a short video clip of the inflow.
Next, I have some pictures from DeKalb, IL. This is from the rather wicked snowstorm on March 28. These pictures were taken March 29 at around 2:15 pm. Unfortunately, the snow had started to melt, so I could not capture the full effect of the storm on camera. Earlier in the morning, the snow was much higher than what I caught on camera later in the day. I regret not getting some pictures of the higher snow, but I have some pictures nonetheless.
Well, that is all for this post. Just posting these few things for now. Hopefully another forecast will be coming up soon, but school has to take priority.
The first is from March 9. This was the day before the "Man vs. Machine" contest. I was on spring break, and what a way to start it with some severe weather. There was a tornadic storm roughly twenty miles northwest of Alton, IL. Here are the SPC Storm Reports from that day. From my house, I was standing in the inflow. It was relatively calm, and then strong sustained winds blew in the direction of the storm. I have a short video clip of the inflow.
Next, I have some pictures from DeKalb, IL. This is from the rather wicked snowstorm on March 28. These pictures were taken March 29 at around 2:15 pm. Unfortunately, the snow had started to melt, so I could not capture the full effect of the storm on camera. Earlier in the morning, the snow was much higher than what I caught on camera later in the day. I regret not getting some pictures of the higher snow, but I have some pictures nonetheless.
Well, that is all for this post. Just posting these few things for now. Hopefully another forecast will be coming up soon, but school has to take priority.
Thursday, March 12, 2009
Forecast Verification
Just as important as the forecast is the verification. In the man vs. machine contest, the only way to guage the results is to look at what actually happened.
Alton:
Tuesday Night:
Actual Low: 29
Forecast:
Man: 29
GFS: N/A
NAM: 28
Wednesday:
Actual High: 36
Forecast:
Man: 40
GFS: 46
NAM: 41
Actual Precip Total (for the forecast period): 0.16"
Forecast:
Man: less than 0.25"
GFS: less than 0.1"
NAM: 1.0" or greater
All three (man, GFS, and NAM) were correct on sky cover, as Wednesday was clear.
So, the results lay in the eye of the beholder. It really depends on what each individual believes. I believe I beat the computers. My low was spot on, I was off on my high, and a little high on precip totals. However, I believe my results were closer to the actual readings than the models.
My mistakes are explainable. For my high, I chose a target too far south, but at the time, it was the only area behind the front in sunlight. As for rain, I believed that there would have been heavier rain associated with the band of showers.
Well, that raps up this contest of man vs. machine. Hope you enjoyed it as much as I did!
Alton:
Tuesday Night:
Actual Low: 29
Forecast:
Man: 29
GFS: N/A
NAM: 28
Wednesday:
Actual High: 36
Forecast:
Man: 40
GFS: 46
NAM: 41
Actual Precip Total (for the forecast period): 0.16"
Forecast:
Man: less than 0.25"
GFS: less than 0.1"
NAM: 1.0" or greater
All three (man, GFS, and NAM) were correct on sky cover, as Wednesday was clear.
So, the results lay in the eye of the beholder. It really depends on what each individual believes. I believe I beat the computers. My low was spot on, I was off on my high, and a little high on precip totals. However, I believe my results were closer to the actual readings than the models.
My mistakes are explainable. For my high, I chose a target too far south, but at the time, it was the only area behind the front in sunlight. As for rain, I believed that there would have been heavier rain associated with the band of showers.
Well, that raps up this contest of man vs. machine. Hope you enjoyed it as much as I did!
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