Severe Threat Diminishing

The threat for severe thunderstorms this afternoon is diminishing, as clouds have kept the temperature from warming enough. However, showers and storms are still expected to develop along a cold front this afternoon, and there is still a possibility that a few storms could be severe, especially if a few breaks develop in the clouds to allow for a little more heating. The better chances for severe thunderstorms are across eastern Wisconsin, where skies have been partly sunny this morning. The moderate risk area has been shifted well south into Illinois, Indiana and adjacent states, where a major outbreak is possible.

Heavy rain overnight has caused the river to rise (again). A flood warning is in effect at Gays Mills (again), where the river is expected to go above flood stage (again). Only minor flooding is forecast, with a crest of less than a foot above flood stage.

Rain & Storms

First post in a long time, but it's worth it.

An unusually strong October storm system is expected to bring widespread rain and thunderstorms to the area starting later today. Rainfall totals may exceed an inch in some places through tomorrow morning. Thursday could be a very active day. The dry slot is expected to rotate northward into Wisconsin tomorrow morning, shutting off the rain. This may allow for some partial clearing and temperatures warming into the 60s. If this happens, thunderstorms will re-develop along the cold front by late morning or early afternoon. While instability isn't expected to be too high, wind shear in the atmosphere will be very strong, so any storms that develop could certainly become severe, and there is a slight risk of severe thunderstorms over southwestern Wisconsin tomorrow. The greater threat of severe weather is to our south and east. About the southeast one-quarter of Wisconsin is under a moderate risk for severe thunderstorms tomorrow, including Madison and Milwaukee. The moderate risk also covers parts of lower Michigan and Illinois, and all of Indiana. Large hail, damaging winds, and tornadoes are all possible. Ultimately, the speed of the system, amount of drying that occurs in the morning, and the position of the cold front will all determine where the best chances of severe weather will be. The Storm Prediction Center said in its morning outlook that a widespread, possibly significant severe weather event appears increasingly likely somewhere in the region tomorrow.

More Storms, More Flooding

Severe thunderstorms moved across Vernon County early this morning, causing some widespread wind damage and more flooding. Rainfall amounts were less this time, generally one to three inches, but rainfall rates were higher, and in some places water levels were higher than they were Saturday night. The Kickapoo River at La Farge rose quickly from a level of about 6 feet to 11.4 feet overnight, and has since fallen to about 10.8 feet. There were more washouts on area roads due to the rapid runoff. The ground is fully saturated, and cannot possibly handle any more moisture. More storms and heavy rain are in the forecast for tonight through Thursday night. Storms have already developed over western Iowa, and I'm watching these closely to see if they approach southwestern Wisconsin this afternoon. A flash flood watch is in effect through tomorrow morning.

Early Fireworks

7:57 p.m.: It has already been an eventful evening, with severe thunderstorms and heavy rain moving across Vernon County. The tornado watch has been extended until midnight, and a tornado warning was in effect for a time for the northeastern portion of the county. No tornadoes were observed, but rotation was seen in Valley and trees were down in that area. There was plenty of lightning, and torrential rains. Already 2.19 inches as of 7:45 p.m. and still falling, lightly. Currently a severe thunderstorm warning is in effect for southwestern Vernon County, and more storms are moving southeast out of Minnesota. While severe weather is still possible, this may be transitioning into more of a heavy rain/minor flooding event. An urban and small stream flood advisory is in effect until 10:00 p.m.

12:45 p.m.: The fireworks may start a day early this week, in the form of thunderstorms. A tornado watch is in effect until 8:00 p.m. for most of the region. Storms are currently developing over central Minnesota and are expected to move/expand east and southeast as the day progresses. While isolated tornadoes are possible, large hail and damaging winds are the main threats. Conditions are a little more favorable for severe weather over Minnesota, but the threat still exists everywhere. In the meantime, enough breaks have developed in the clouds to produce temperatures in the middle 80s. Dewpoints are increasing rapidly as well, already in the middle to upper 60s, so it feels quite humid. The threat of storms will linger through tonight, but it now appears that tomorrow, the 4th of July, should be rain-free, with seasonable temperatures. Might have to get through some rough stuff first.

And then the heat builds for the weekend.......

High Risk

5:08 p.m.: The severe weather threat appears to be over, and the tornado watch will likely be cancelled in the next hour or so. Severe thunderstorms moved through southeast Minnesota and western Wisconsin, resulting in some wind damage, very large hail, and possibly producing a tornado near Bangor. The storms have moved into northeastern Wisconsin, where several tornadoes have been reported. A tornado was reported just south of downtown Wisconsin Rapids, along with softball-sized hail. A tornado watch is in effect for eastern Wisconsin as well, but storms have not developed there yet. Overall the severe weather was not quite as widespread as expected over western Wisconsin, perhaps due to this morning's cloud cover. Another factor may have been the fact that the boundary that the storms formed along moved into the region a little quicker than expected. Still, this was a significant outbreak in areas mainly north of the Kickapoo Valley, but not as bad as feared.

12:40 p.m.: A Tornado Watch is in effect until 10:00 p.m. This is a PDS watch (Particularly Dangerous Situation), which means the threat for severe weather is very high. Destructive tornadoes, hail up to 2.5 inches in diameter, and wind gusts up to 80 miles per hour are possible. We remain under a high risk for severe weather, and the threat for tornadoes is slightly higher this afternoon than it was this morning. Thunderstorms are rapidly developing across northern Iowa and southern Minnesota, and several warnings have already been issued there. These storms will move north and east toward Wisconsin during the afternoon. The temperature has warmed into the lower 80s and dewpoints are well into the 60s, so the atmosphere is quite unstable. This is a very volatile situation and can change rapidly, so monitor the situation closely as the afternoon progresses and be prepared to seek shelter if these storms approach.

10:08 a.m.: Instead of eroding, the cloudcover has actually increased this morning. This could work to suppress the severe thunderstorm risk this afternoon. However, wind shear remains very high, and dewpoint temperatures have climbed into the middle 60s. Skies are also more clear across parts of Iowa and Minnesota where convective initiation is expected in the next few hours, so the threat for severe weather is still very real.

8:37 a.m.: There is a rare high risk of severe thunderstorms today across all of Wisconsin and adjacent parts of Minnesota and Iowa. All of the parameters for a significant severe weather outbreak still appear to be coming together. It is becoming increasingly warm and humid this morning, with some scattered clouds. Most of Iowa and southern Minnesota is cloud-free at this time, and this clear area is expected to move into Wisconsin as the morning progresses. This will allow the atmosphere to become more unstable. Wind shear values are already high, so thunderstorms are expected to rapidly develop by early afternoon and then move east. Tornadoes, damaging winds and hail are all possible. There is also a threat for some strong tornadoes and widespread damaging winds, with gusts up to hurricane force possible. There is still some chance that this forecast may be a bust, but it looks more and more like it will be a stormy afternoon across the area.

Dangerous Thursday

It appears that all the ingredients are coming together to possibly create a widespread, significant severe weather outbreak across the region on Thursday. An unseasonably strong storm system is developing across the northern plains today, and this is expected to drive a strong cold front through the Upper Midwest tomorrow. Wind shear values are terrifyingly high, which leads to a high probability of severe thunderstorms. The entire region is currently under a moderate risk for severe storms. The most likely scenario would see thunderstorms rapidly developing across eastern Minnesota and Iowa early tomorrow afternoon. Tornadoes, some of which could be strong, will be possible with early supercells that develop. These discrete storms are then expected to form into a rapidly-moving squall line which is then forecast to move across Wisconsin late Thursday afternoon and evening. Widespread damaging winds are possible with this line, an event known as a 'derecho'.

There are two factors that could limit thunderstorm development. The first is the convection that is expected to affect the Dakotas and Minnesota tonight. A widespread severe weather event is anticipated there, but it is forecast to remain well to our north. However, if any of this precipitation makes it to southern Wisconsin, or debris clouds linger across the region tomorrow morning, the severe threat will be reduced. At this time, this is not expected to happen. The second inhibiting factor is the wind shear. While strong wind shear favors severe thunderstorms, in this case it is possible that the shear will actually be too strong, and the storms will be ripped apart before they can fully develop. Basically, this will probably be one of those "all or nothing" scenarios. If storms get going, they will likely be some really bad ones. If one of these two factors mentioned above comes into play, we may not get much of anything. Despite this, severe weather looks likely tomorrow afternoon, and if everything comes together right, it could be a bad day.

Ongoing Severe Threat part 2

No severe weather developed in the valley yesterday, but a brief tornado in Lafayette County was rated EF0 and a much stronger tornado in Muscatine County, Iowa was rated EF3. There is still a severe weather threat this afternoon, as partly sunny skies will allow for some destabilization of the atmosphere. The most likely scenario is for thunderstorms to develop over central Iowa and Minnesota during the afternoon hours and then track eastward into Wisconsin. This morning's rain and cloudcover has stabilized the atmosphere for now, so the severe weather threat is not as great as it could be, but it still bears watching.

Overnight storms?

A severe thunderstorm watch is in effect just to our south. Thunderstorms have rapidly developed over Iowa in the past hour, and several severe thunderstorm warnings are already in effect. These storms could move north into Wisconsin overnight. Heavy rain and large hail would be the main threats.

Side note: You know it is April when a severe thunderstorm watch is in effect for southern Wisconsin, while a winter storm warning is in place across the north.

Nothing confirmed

The National Weather Service has not confirmed any tornado touchdowns from yesterday, and I doubt they will. If any tornadoes actually formed, they likely only lasted a few seconds or minutes and caused little, if any, damage. Yesterday's weather pattern didn't favor the development of damaging, long-lived tornadoes. Even if nothing is confirmed, the tornado warnings were still justified in such a quickly-evolving weather situation.

Cool and damp today. Most of tomorrow should be rather nice, with some sunshine and mild temperatures. The next storm system will approach by tomorrow night, bringing more rain and storm chances. There is a slight risk of severe thunderstorms tomorrow night, and the main threat will be large hail. After that, cold.

Watching for storms

7:17 p.m.: A line of storms has quickly moved through the area, prompting several tornado warnings for Vernon, Richland, and Grant counties. No confirmed tornadoes or damage yet. This was a very complex situation and any tornadoes or funnel clouds that may have formed would likely have been weak and short-lived, and may have even gone unnoticed. The severe weather threat should now be over, but rain could continue for a few more hours.

5:58 p.m.: Tornado Watch in effect this evening. A line of storms is moving north-northeast out of Iowa. Large hail, damaging winds and heavy rain will be the biggest threats, but there is still a chance for an isolated tornado or two.

Link to tornado watch: http://www.spc.noaa.gov/products/watch/ww0102.html

12:21 p.m.: Am keeping an eye on the weather picture this afternoon for the potential for some strong/severe storms. Isolated storms are developing across the area right now. A more concentrated area of storms is expected to develop over Iowa as the afternoon progresses, and this is where the greatest threat for severe weather will be. However, a warm front is expected to be located across the region by later this afternoon, and it is not out of the question that severe storms could develop along it as well. Overall, there will be a very narrow window for severe weather development, generally between 3 and 10 p.m. If all the conditions come together, severe storms could be more widespread than currently predicted. I will eagerly await the 3:00 p.m. severe weather outlook.

Storms tomorrow

After rain this morning, the rest of the day has been just cool and cloudy. More rain is coming though, especially tomorrow. There could be periods of heavy rain, mainly later tomorrow, and possibly a few severe storms. The severe weather threat is highly conditional. The location of the dry slot with this system will be the key. (A "dry slot" is a large area of dry air being wrapped into a storm system; these meteorologists can be quite clever when they name these features). Skies could become partly to mostly sunny under the dry slot, which would increase the instability and therefore enhance the severe weather threat. If skies remain cloudy, the chance of severe weather will be greatly diminished, and any severe storms would be more isolated. There will also be a warm front in the area, and those can be quite unpredictable. It will be an interesting day.

More rain will be likely early next week as another strong storm moves through. Some much colder air will move in behind this particular system, bringing a chance of snow as well. Temperatures are expected to be below normal for at least the first half of April, unfortunately.

Where Did Spring Go?

After two days of record highs in the 80s, spring has seemingly disappeared already. The past two days have been much cooler, and cloudy skies and occasional rain showers have really made it feel dreary (and have made me extremely tired). This is actually what early spring is supposed to be like, we were just spoiled (as usual) by a brief period of late-spring-like weather.

Major severe weather outbreak in the Plains last night. Several reports of tornadoes in Texas, Kansas, Nebraska, and Colorado. At least four fatalities so far. The only good thing is that most of these storms affected rural areas, so damage and casualties will be considerably less than if more populated areas had been hit. Meanwhile a blizzard has been raging in Wyoming. All of this is due to a strong spring storm system (say that 10 times fast...) that is slowly headed our way.

Rain and thunderstorms will become increasingly likely beginning tonight, with the best chances likely occurring Friday night and Saturday. Depending on how this whole thing plays out, there is at least a small chance for severe thunderstorms on Saturday. The Storm Prediction Center doesn't have the area in any kind of an outlook yet, but this morning's forecast discussion from the National Weather Service in the Quad Cities contained this little tidbit: "UPPER LEVEL SYNOPTIC SCALE SIGNALS (just fancy words for things going on up high in the atmosphere)ALL THERE THOUGH FOR A SIGNIFICANT SEVERE WEATHER EVENT SOMEWHERE ACROSS IA/SOUTHERN MN/WI AND
NORTHERN IL BY SAT EVENING." Surface conditions, however, may not be nearly as favorable, depending on how this whole situation evolves. More on that later.

Severe Day

8:19 p.m.: Tornado watch cancelled. Forecast was a major bust, again.

6:54 p.m.: This year's severe weather season appears to be picking up where last season left off: wrong. Today's "outbreak" hasn't been nearly as widespread as expected, with only a few reports of severe weather mostly across west central Wisconsin. Some storms may be trying to get going just to the west of the Mississippi River but unless they do so in a hurry it looks like our severe weather threat is rapidly diminishing. But, the watch continues to be in effect, as there is still a potential for storms to turn severe quite rapidly before they completely clear the area.

3:45 p.m.: Tornado Watch is in effect until 10:00 p.m. tonight. Thunderstorms are beginning to develop over southern and eastern Minnesota and are expected to intensify and move into Wisconsin in the next several hours. It may take a couple more hours before things really get going. Otherwise, it has been a nearly perfect weather day, with record high temperatures in the upper 70s and lower 80s, with mostly sunny skies (that are now becoming partly cloudy) and some rather gusty winds.

Link to Tornado Watch: http://www.spc.noaa.gov/products/watch/ww0075.html

10:15 a.m.: There is a moderate risk of severe thunderstorms this afternoon and evening. Tornadoes, hail and damaging winds are all possible. The greatest threat time will be between 3:00 and 10:00 p.m. More to follow, if necessary.

Springtime

The blizzard of '07 began one month ago today, but all traces of it are now gone. Spring is definitely here. There has already been some flooding (11.38 feet on the Kickapoo River at La Farge last week, not quite flood stage but close enough), unseasonably mild temperatures (66 degrees today), and some isolated severe weather. Storms on Wednesday night brought pea-sized hail locally with some isolated reports of penny- and nickel-sized hail in parts of the region.

The weather pattern remains very unsettled. Showers and thunderstorms are likely tomorrow night as another warm front moves northward, and there is a slight risk of severe thunderstorms on Sunday. A stronger storm system is currently forecast to impact the region around the middle of next week, and could bring another chance of severe storms. Severe weather is not altogether uncommon in late March, but it is rare to have more than one outbreak.

Heavy rain will also be a big concern during this period. About six-tenths of an inch fell during Wednesday's storms, which caused the river to rise nearly three feet here. This is because the ground is saturated from the recent snowmelt, and is still frozen at greater depths. Flooding conditions could redevelop if heavy rain does occur. Something to watch...