Last Post of 2010

Hey all,

This being New Year's Eve, this will be the last post of 2010. I originally planned on writing a forecast for tomorrow, but my plans were changed this morning. I got online to look at weather, seeing that most of the St. Louis area was under a tornado watch. Within minutes, there were tornado warnings posted. I jumped into "Severe Weather Mode" which kept me glued to radar and the skies. After the reports are completed, I'll put them up here for you to see. The severe weather mostly stayed south of Alton, so no cool pictures from me this time.

On a slightly different topic, with the new year coming, I am wondering if there are anythings you would like to see on the blog in 2011. I've been leaving forecast verifications in the comments section starting this year. If there are anythings you would like to see (that are reasonable), I'll see what I can do on putting them on this blog. Also, if you are just an occasional reader, but would read more often if there was some improvements, please let me know. Anything that helps spread the word on the weather. So please, if you would like to see changes, write a comment in the comments section, and I'll see what I can do.

Well, I'm going to keep this short and sweet. Have a safe and happy new year! I'll write to you all in 2011!

Snowfall Update

Hey all,

Here's the latest update on snowfall totals. I really cut it close on the Alton forecast. While areas in St. Louis were recording 4 inches or greater, I measured 3 inches in Alton. Just clipped my upper limit on that forecast! Other reports from around St. Louis.

I was just a bit too low on DeKalb, as the official report was 5.1 inches. Looks like the snow to liquid ratio was a bit higher than I expected, but that is weather for you. Here are the reports from around Chicago.

I hope everyone enjoyed their day! Merry Christmas!

I'm Dreaming....

'Tis the season of giving, so today I am giving a double forecast. With Christmas being just 2 days away (really seems like the year went fast), there is always the conversation of whether or not there will be a white Christmas. There is a nice set-up out in the West, and it is heading for the Midwest. It's time to see if Alton and/or DeKalb will have a white Christmas!

Let's start by looking at the system. The jetstream has a very nice trough out west, with the trough axis in central Utah as of 1200Z (6 am CST). This trough will continue its eastward journey, and by midday tomorrow (Christmas Eve) the trough axis should be around the Oklahoma Panhandle. Current forecast models show that the trough will then track across Illinois, and moving out of Illinois Christmas morning. As this trough approaches Illinois, the lower level winds (at 850 mb), will begin to flow from the south, bringing in some moisture from the Gulf of Mexico. This will contribute in forcing precipitation from this system. After this trough passes, Illinois will be sitting under a fairly large ridge.

Normally, I would be getting ready to blame some surface feature for the possibility of precipitation. This time, it appears there will be another forcing mechanism for the snow. The low in Colorado is looking like it will take a southern turn, and come evening Christmas Eve, the low should be crossing Texas. With a ridge following in the jet stream, Illinois will mostly be seeing high pressure at the surface after this event.

Currently, the cause of possible snow, seems to be isentropic forcing. This will take a bit of explanation, and I will do the best I can to explain it. Please remember, I am trying to explain a complex process as simply as I can.

In meteorology, we have a variable known as potential temperature. This is the temperature that an unsaturated parcel of air would have if you brought the parcel adiabatically to 1000 mb pressure. Here's the big deal about it for purpose of this discussion: Parcels like to "ride along" on this temperature. The parcels basically treat this as a sort of "ski lift." I'll bring in a chart soon which should help you visualize this.

Here is the cross section of the atmosphere between Slidell, LA (left) and Green Bay, WI (right) (conveniently right through the forecast area!) The red lines are lines of potential temperature (in meteorology, commonly called "theta", since that is the variable used in calculations.) Notice, as the potential temperature lines approach Green Bay, they go up in height. Remember, parcels are riding along this line of potential temperature. As the parcels rise, their actual air temperature decreases, and brings it closer to the dew point. When the air temperature and the dewpoint temperature reach the same temperature, you have saturation. As the atmosphere reaches saturation, you begin to form clouds and can form precipitation.

Basically, isentropic forcing is when you get this type of situation, where parcels are "riding" lines of potential temperature and forcing out precipitation. There is a whole lot involved in this process, but I am really trying to give a very simple explanation for something that is not very simple. However, this appears that it will be the culprit for any snow caused on Christmas Eve and into Christmas day.

Now for the fun part, which is snowfall accumulation. So I'll start with Alton, and then I'll finish with DeKalb.

For Alton, IL, models seem to put the best time for snow to be in the afternoon into the evening on Christmas Eve, with snow falling overnight, and flurries on Christmas. MOS guidance shows probabilities of precipitation to be well over 70%, so it looks like Alton, IL will be having a white Christmas! As for amounts, based on what I am seeing, I feel confident that there will be about 1-3 inches of snow across the area, with local amounts reaching 4 inches.

For DeKalb, IL, everything seems to be pointing to similar conditions. It looks like the snow may begin around the middle of the afternoon on Christmas Eve, but these will more than likely be flurries. The snow should pick up into the evening hours, and it looks like there may be a few flurries on Christmas. MOS guidance isn't as high as Alton, but still shows around a 70% chance of precipitation on Christmas Eve. All in all, I believe DeKalb, IL will also be having a white Christmas! Based on the data, I am going with 2-4 inches of snow for DeKalb, with local amounts being up to 5 inches.

Well, that concludes this discussion. It looks like both areas will be having a white Christmas. If anyone is wondering what I'm wishing for, it would be a job (even part-time) or funding so I can go to graduate school in the fall, but that's another story, for another day. Have a safe and enjoyable holiday. Merry Christmas everyone!

All Sorts of November Craziness!

A few posts ago, I was talking about how weird this particular November has been. Well, just about a week after that post, November decided to keep up the craziness. When I think of the month of November, I'm thinking overcast skies, drizzle, and colder temperatures. This past week in the state of Illinois, that normal expectation has been thrown out the door. Illinois has had thunderstorms, tornadoes, flooding, and freezing rain all in a short time span.

If you are anything like me, the first word on that list that jumped out was "tornadoes." This was especially true for those of you in northern Illinois. I was stunned when I heard about a November tornado, but the National Weather Service in Romeoville, IL has a great article on the event, as well as a nice picture of the tornado. They also provide a nice recap of the event, so I'll pass those on for you to read. The following hyperlinks will take you to those stories:

The first article (with the picture of the tornado)

Updated version (no tornado picture, sadly)

Confirmation story (with damage photos and storm reports)

Late season tornado climatology (interesting read)

SPC Storm Reports


Now for the rest of the November mayhem. While all of that fun was occurring up north, the weather had other plans for the greater St. Louis area. There were some tornado warnings issued with a long line of thunderstorms, but no tornadoes were reported in southern Illinois (there were a few in central Missouri.) The Wednesday before Thanksgiving was a wet day, as rain fell almost all day. This rain continued into Thanksgiving day, where it later switched into a nice wintry mix of snow and sleet. Here is a link to the rain totals as collected by the St. Louis, MO National Weather Service.

In short, it has been a highly eventful November. I hope you all enjoyed these stories, and I hope you all had a Happy Thanksgiving.

Football Forecast

Here we go with a "floater forecast." This is one of the forecasts not for Alton or DeKalb, but rather somewhere else in the nation. This forecast is for Muncie, IN, where the Northern Illinois University Huskies will take on the Ball State Cardinals in football on Saturday!

First off, how about those Huskies?! NIU is 8-2 overall this season, with a perfect 6-0 record in conference (MAC) play. Only 5 other teams in the nation are undefeated in their respective conferences. NIU is also ranked 29th in the nation in both the Coaches and AP polls! They will be facing the Ball State Cardinals (4-7, 3-4 in conference (MAC)) in Muncie, IN at 11:00 AM (CST). The Huskies only need to win 1 of their last 2 games to become MAC West Champions. Since the sports stats are done, let's look at what the weather may be for this game.

Across the Midwest, the jet stream is in a ridge pattern. This should bring warmer than average temperatures as well as nice weather. Just north of this ridge, in eastern Manitoba/western Ontario, there is a small shortwave in the jet stream. This shortwave is just behind a surface low.

Speaking of the surface, the surface map is a bit active. There is a low in Ontario, with a cold front extending through Wisconsin, Iowa, northwestern Missouri, and Kansas. West of the Rocky Mountains, there are many different surface lows, in the states Idaho, Oregon, Nevada, California, and Wyoming.

The primary concern is the low in Ontario. The cold front associated with this system will move towards the southeast. At this time, it is looking like the cold front will be near Muncie, IN around 1:00 PM (EST). Since the game starts at Noon EST, this front should hit during the game. It is associated with a occluding (weakening) system, and since this system does not have a strong pressure gradient, it should not affect wind speeds too much. Additionally, the lack of moisture in the area will eliminate the possibility for rain.

Examination of both surface data and Model Output Statistics (MOS) guidance, shows that temperatures should be a bit chilly, but good football weather, with the high expected to be around 53 degrees. Temperatures should be in the upper 40s/lower 50s around kickoff, and warm up throughout the game.

10/20/10 Muncie, IN Forecast:
Overnight Low: 36
Daytime High: 53
Kickoff Temperature: 49
Winds: 5-10 MPH out of the South
Conditions: Partly Cloudy

And it wouldn't be a football forecast without a score prediction. I admit to being bias towards NIU, since I spent a great 4 years of my life there, but I will try to keep bias out of the prediction. So, here's my prediction:

NIU 42
BSU 17

Let's see how both the forecast and prediction turn out. I'll leave you with this: GO HUSKIES!

Alton, IL 10/18/2010 Forecast

Simply put, this has been a weird November. There is a quote for Midwest weather patterns which has been true for this month. "If you don't like the weather, wait 15 minutes, and it will be different." Okay, maybe not 15 minutes, but the weather changes over one week has been incredible. Last week, we were experiencing temperatures in the upper 60s and into the 70s in Alton. The weather was nice enough, that one could have worn shorts if they so desired. This week, the weather has people grabbing jackets before heading out the door. That being said, let's take a look at this weather!

Let's start by taking a look at the surface map. Remember, this link will provide the current surface map, so it may be different than the map at time of this discussion. There are 3 low pressure systems spread across the country right now. The first low is in Canada, just north of New York state and Vermont. The next low is the one impacting Illinois. This low is in northeastern Oklahoma/southwestern Missouri. This low will be discussed in greater depth for this discussion. The last low is sitting out in the Pacific Ocean, northwest of Oregon, and it may cause forecast issues this weekend into early next week.

The main forecast concern for Alton is the low in northeastern Oklahoma/southwestern Missouri. This low is occluding, which means the system is weakening. This low has a warm front extending into portions of southern Illinois. Being north of the warm front puts us in prime position to see some precipitation. The radar from the National Weather Service in St. Louis, MO shows a "precipitation shield" heading towards the greater St. Louis area. This is mostly light rain, and should impact the area during the early morning hours of the 18th. This is mostly light rain, although lowering temperatures overnight may cause the occasional snowflake, but no accumulation is expected.

Upper air analysis shows the area is under a trough, but forecast models project that the area will be out of the trough midday tomorrow. Then a ridge will dominate the weather pattern for the next few days, bringing warmer temperatures along with dry conditions.

Overall, not too many major weather shifts should be expected over the next few days. Basically there should be some rain overnight on the 17th into the early hours of the 18th, and then rain is out of the forecast until the weekend. In that time span, temperatures should warm up a bit, but nothing as warm as last week. It looks like fall is going to try to stick around the area for a little bit.

10/18/2010 Alton, IL Forecast:
High: 47
Overnight Low: 36
Rain Amount: Less than .10"
Conditions: Mostly cloudy, with clouds decreasing during the day

10/19/2010 Alton, IL Forecast:
High: 57
Overnight Low: 33
Rain Amount: 0"
Conditions: Clear skies

I would like to add a quick note. I have been encountering some technical issues recently, or else I would have posted sooner.

Big Storm Wrap-Up

To say the very least, it has been windy the past few days. The recent storm was one we will not see for a while. This storm was historical to say the least. I'd like to make a quick correction before diving into this post. In the last post, I said the Edmund Fitzgerald storm reached a pressure as low as 976 mb. The lowest recorded pressure was 980 mb. The 976 mb pressure I discussed was actually from a simulation of the storm.

As for the 980 mb pressure in the Fitzgerald storm, it was blown away by the pressure in this last storm. This recent storm's lowest pressure reached 954 mb! Remember that 1013 mb is standard atmospheric pressure. The low in this storm was almost 60 mb below standard atmospheric pressure, which is extremely rare in mid-latitude cyclones. Here is a surface map from the Hydrometeorological Prediction Center of this storm at its peak intensity:

This surface map only shows the pressure at 956 mb, but just a few hours afterwards, this system hit 954 mb.

Not only did this system hit an astounding low pressure, but it also produced numerous storm reports. At one point, there were tornado warnings extending from Michigan to Alabama, while there was a blizzard in North Dakota, and it was all from the same system. Here are the Storm Prediction Center damage reports over a 3-day period where this system was producing violent weather. Blue marks are damaging wind, green is hail, and red is tornadoes.

October 25, 2010

October 26, 2010

October 27, 2010

The wind damage produced in Illinois on October 25 was mostly overnight into morning. From there, the storm continued producing damaging winds, and it even went on to producing tornadoes.

This storm has mostly moved out of the United States, with just a few remnants of the system remaining. Its pressure has risen back to around 996 mb (not nearly as intense as it was). It is always fascinating how powerful these big historic systems can become. I know I will remember the excitement and awe of watching this storm for a long time.

Dropping a Meteorological Bomb!

Hey all!

First, I apologize for my lack of any posting in months. I thought I'd have time after getting back to school to put up the post, but I then realized I couldn't find the camera cord (so no pictures then). Then classes, homework, and organizations kept my week booked, often leaving me working into the wee hours of the morning. Then bad habits started of not posting, but there's no excuse for my lack of posting now, so I will start posting more often. Again, I apologize.

The reason I had a big urge to post tonight, is because out in the plains right now sits a large low pressure. While this low was sitting out in western Nebraska, storm warnings were being issued by the National Weather Service over Lake Michigan and Lake Superior. The NWS is calling for winds over Lake Michigan to reach up to 60 knots (about 69 mph winds)! They are also predicting wave heights to be as high as 20 feet, with the occasional wave reaching 30 feet high! As of 11:15 pm (Central time), the low pressure with this system was 980 millibar (mb for short). For those not used to pressure in millibar, 1013.25 mb is a standard atmosphere. Basically, this storm is roughly 30 millibar below standard atmospheric pressure, and still intensifying! What makes this storm a bomb is the pressure drop. A meteorological "bomb" is a storm that drops 24 mb of pressure in 24 hours. That is a rapid intensification for any storm, and generally these bombs produce big weather events.

The low pressure is associated with a strong pressure gradient, and this will be the primary reason for the intense winds. Here is the last surface map from the Hydrometeorological Prediction Center. The map will update with time, so it may be different while you examine it.

For some historical reference, the storm that sunk the Edmund Fitzgerald back in 1975, was producing winds around 40-50 knots (46-58 mph)! A reading was from the then nearby ship Arthur M Anderson measured wind gusts at 75 knots (86 mph)! Wave heights with this storm were around 18-25 feet tall waves. Pressure with this storm got as low as 976 mb!

To make this system even more fun, there is a nice cold front associated with this system. This will allow thunderstorms to fire up along the front. The Storm Prediction Center has already been issuing outlooks for severe weather potential over land. A moderate threat for severe weather has been issued by the SPC for Tuesday, October 26, 2010. The primary threat with this system will be damaging winds across most of Illinois. Basically, with the SPC issuing a 45% chance of damaging winds, there is a very good chance of seeing them (scroll over the "wind" portion of the banner to see the percentages). If you noticed the hatch marks on the map, that may require an explanation. Since this is primarily a wind threat, I'll explain with wind. If you are in an unhatched area (and have a probability above your location), you have that percent chance (say 25%, for example) of seeing 50 knot wind damage 25 miles from any point in that location. If it is hatched, then expect that percent (in this case 45%) chance of seeing 65 knot wind damage 25 miles from any point in the hatched area. Since most of the state of Illinois is under a hatched region, there will more than likely be a lot of wind damage reports across the state.

So basically, try not to get blown away (literally), but be ready to be "blown away" (figuratively) by the awesome spectacle we are about to witness. We probably won't see a storm this strong for a while.

Big Post Soon

Hey all!

I am currently in Atlanta, Georgia at the National American Meteorological Society Meeting. I got selected as a student volunteer, so it is almost like getting paid a bit to go to the conference! Anyhow, I have some pictures (but no camera cable) and some stories to tell, but I am goint to post them after the meeting (and upload the pictures).

-Chuck