Holiday Weekend Weather

There is the potential for some storminess over the 4th of July holiday weekend. A series of low pressure systems and fronts will move through the region, and each will bring a chance for storms. The first round of storms could move through Saturday morning. Storms have already developed over the Dakotas and western Minnesota, and they could form a broken line that might move through tomorrow. A front will move through the region during the day tomorrow, bringing another chance for storms later in the day. The front will be near the area Sunday as well, and could be the focus for more storms then. Storm chances will linger into Monday, before finally moving out just in time for Independence Day. There is at least a slight weather with any of these storms, but at this time it does not appear that there will be any widespread outlooks. Furthermore, the overall coverage of the storms is not expected to be widespread either, so it will not rain the entire weekend. Instead, there will be periodic chances for rain, with not all areas getting wet.

Weekend Update

Update--4:39 p.m.: Severe Thunderstorm Watch until 9:00 p.m. A few isolated storms developing across southeast Minnesota and west central Wisconsin. Hail and gusty winds remain the greatest threats, along with heavy rain.

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 554
NWS STORM PREDICTION CENTER NORMAN OK
340 PM CDT SAT JUN 24 2006

THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

SOUTHEASTERN MINNESOTA
WEST CENTRAL WISCONSIN

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 340 PM UNTIL 900 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.


Previous entry: Showers and thunderstorms will be likely today, with a slight risk for some isolated severe thunderstorms. Conditions are not right for a widespread severe weather outlook, but there could be a few reports of large hail or gusty winds. According to the National Weather Service, the most favorable time for storms will be between 2 and 8 p.m. today. Storms may linger into tomorrow morning, but are expected to clear the area by afternoon. Otherwise, temperatures will likely be below normal, with highs in the 70s.

Worrisome Wednesday

Update--8:37 p.m.: After two days of watching and waiting, the threat for severe weather has finally passed. After the noontime storms moved through, no new storms were able to develop ahead of a cold front advancing toward the area. The front has now moved through, so thunderstorms are no longer expected. Hopefully the next severe weather forecast will be more accurate than the ones of yesterday and today.

Update--11:20 a.m.: Severe Thunderstorm Watch just issued, in effect until 6:00 p.m. Storms moving in from northeast Iowa. Biggest threats are hail and wind.

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 527
NWS STORM PREDICTION CENTER NORMAN OK
1100 AM CDT WED JUN 21 2006

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EASTERN IOWA
NORTHERN ILLINOIS
NORTHWEST INDIANA
SMALL PART OF SOUTHEAST MINNESOTA
SOUTHERN WISCONSIN
LAKE MICHIGAN

EFFECTIVE THIS WEDNESDAY MORNING AND EVENING FROM 1100 AM UNTIL 600 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.


Previous entry: Thunderstorms finally developed along the warm front last night, and continue to affect southern Wisconsin this morning. There have been several reports of wind damage, including numerous trees down in the Janesville and Beloit areas. These storms should remain south of the Kickapoo Valley, but there is a chance for more storms to develop further north, possibly bringing us a large hail threat. Additionally, a cold front will approach the region from the west early this afternoon, and if enough instability can build ahead of this front, a squall line could form along it and present a threat for some gusty winds. There is a slight risk of severe weather across the entire region today, but it does not appear that there will be widespread severe storms here. Yesterday's severe weather forecast was well off the mark, and I fear today's forecast will be the same.

Troublesome Tuesday

Final Update--10:00 p.m.: Atmosphere is very convoluted tonight, with numerous boundaries that could be the focus for convective development overnight. The most likely scenario is still for storms to develop north of the warm front in Iowa, and then move east into southern Wisconsin and northern Illinois. Hail remains the biggest threat with any storms that may develop. Overall, not a very good forecast today.

Update--4:26 p.m.: Morning/early afternoon convection and clouds really stabilized the atmosphere across much of the region. Severe thunderstorm chances for this evening into the overnight still exist, however, as a warm front remains to our south in Iowa. This front will help thunderstorms develop during the next few hours, most likely across western Iowa. These storms are then expected to move east toward southern Wisconsin. If any storms make it into the area, large hail would be the biggest threat, but some damaging winds or an isolated tornado cannot be ruled out. Still a lot of wrinkles to be ironed out though, so storms are far from certain at this point. Another complex of storms developing over western Nebraska at this time may move through the region during the day tomorrow, and could pose a threat for some strong storms then.

Previous entry: A complex of showers and thunderstorms is moving eastward into Wisconsin this morning, and should arrive before noon. This complex may weaken somewhat before it arrives, but currently it looks like rain is likely this afternoon. However, this complex is not the big threat for today's weather. A warm front over Iowa is forecast to slowly lift northward today, and thunderstorms are expected to rapidly develop near the front later in the afternoon. These storms could quickly become severe, with a threat of large hail, damaging winds, and isolated tornadoes. These storms could then move into Wisconsin during the evening hours, possibly continuing overnight. Currently, the Storm Prediction Center has southwest Wisconsin, southeast Minnesota and northeast Iowa in the most favorable area for severe storms, but this is going to be highly dependent on what this morning's ongoing thunderstorm complex does. If this complex clears and northern Iowa/southern Minnesota area by noon, which it is forecast to do, then that area will become quite unstable, creating a more favorable environment for storms to develop. Even if we remain cloudy most of the day, these storms could remain severe if they move into the area later on. Overall this is a very messy forecast, but if everything comes together, it could become quite volatile later on. We are in a slight risk of severe weather at this point, but the Storm Prediction Center may need to upgrade parts of the region to a moderate risk as the situation becomes clearer throughout the day.

Uncertainty

Still a lot of uncertainty in the forecast for the weekend. There is a chance for thunderstorms tonight, but it is looking more and more like most of this activity will remain to our north and west, and I wouldn't be surprised if we stay completely dry here. Thunderstorms are likely later tomorrow afternoon and evening, and there is a slight risk of severe storms, but this will be highly dependent on how much sun we get tomorrow. Debris cloudiness from tonight's storms may linger across the area, and this will limit the instability. If we can get even an hour or two of sun, however, the severe weather risk will be greater. If storms do develop, they will likely produce heavy rainfall as well. In fact, there are numerous flash flood warnings in effect for counties in central and southern Minnesota in association with tonight's storms. Temperatures will also be highly contingent on the clouds. If there is enough sunshine, the mercury will likely approach (and possibly exceed) 90 degrees tomorrow. Overall, the forecast remains highly uncertain, with a high 'bust' potential. Oh, the joys of summer weather forecasting...

Stormy Weekend?

The weather pattern is about to become a bit more snarky the next several days. A frontal boundary is expected to be located across the area starting late tomorrow. Several pieces of energy are forecast to move along this boundary, and each will bring a chance for showers and thunderstorms. This is where it gets interesting.

The exact timing of these thunderstorm complexes is uncertain, and this will determine how warm it gets each day. During this type of pattern, the best storm chances are in the late afternoon, continuing into the overnight hours. Depending on how quickly these storms move out the following morning, it could get quite hot over the weekend. If skies remain mostly clear during the day, temperatures in the 90s will be likely. If there are more debris clouds hanging around, highs in the lower 80s will be more common. According to the National Weather Service, there will also be chances for severe thunderstorms and heavy rainfall, especially Friday night and Saturday night.

This is a very summerlike weather pattern but the details are highly uncertain at this point, hence the "snarky" comment at the beginning. Hopefully these details can be ironed out in the next few days. Nonetheless, it could be a rather stormy weekend.

Impressive Rains

A large complex of showers and thunderstorms moved across the region early Saturday morning, producing some rather impressive rainfall totals in the process. Had about an inch in my rain gauge, but there were higher totals to the south and west: 2.25 inches in Lancaster, 2.12 inches in Caledonia, 1.78 inches in Genoa, 1.61 inches in Gays Mills, and 1.42 inches in Richland Center. Fortunately there were few flooding problems, as the ground was dry enough that it could handle some excessive rainfall. Some unusually cool and dry air has been flowing into the region this weekend, making it feel much more like early May than mid-June. A warming trend is expected to begin this week, with temperatures rebounding into the 80s by midweek (and possibly going higher by next weekend). Hopefully this expected summerlike weather will stick around for awhile.

Also have to welcome Tropical Storm Alberto to the weather scene. Alberto is the first named storm of the 2006 Atlantic season, and is expected to visit Florida this week, albeit as a very weak system. I will probably mention tropical weather frequently during the summer. Tropical systems rarely affect us in Wisconsin, but sometimes the moisture from a system can spread cloudiness and rain this far north. Nonetheless, tropical weather has always been a point of interest for me, so don't be surprised to see some tropical talk here from time to time.

June 6, 2006 Tornadoes

Thunderstorms that developed over western Wisconsin on Tuesday afternoon became severe as they headed eastward, spawning three tornadoes in the process. An F1 tornado moved southeast along a 16-mile path in Columbia County, and two F0 tornadoes briefly touched down in Iowa County, one south of Spring Green and another just west of Barneveld (no doubt bringing back some bad memories to residents there, especially just two days before the anniversary of the F5 tornado that destroyed that town). All three tornadoes affected rural areas, and the most significant damage was to mobile homes. More information from the National Weather Service at this link: http://www.crh.noaa.gov/mkx/?n=060606_tor.

That brings the 2006 Wisconsin tornado count to 4, which is a little quiet for this time of the season. Most of the severe weather this season has been fairly isolated. The only widespread event was the April 13th hailstorm in the southern part of the state. No severe weather is expected for the next several days.

Changes Ahead

The weather lately has been very tranquil (and somewhat boring), with warm days, cool nights, and no rain. That should be changing soon. Scattered thunderstorms over Minnesota are moving east and southeast toward Wisconsin, and if they hold together they should arrive sometime overnight. The biggest threat should be heavy rain, but there is a remote possibility of an isolated large hail report or two. Better chances of severe weather tomorrow, but it will be highly dependent on how much cloudiness there is tomorrow morning. Fewer clouds = better severe chances.

After this system moves out, it should quiet down again for a few days, but storm chances will return by the weekend. A very summer-like weather pattern could set up, with thunderstorm complexes developing over the Dakotas and Minnesota during the evening, then propagating west and southwest across Wisconsin at night. Still far from certain though. But is the weather ever certain?