Morning Severe

The SPC has issued a new severe thunderstorm watch for northern Iowa as a line of thunderstorms with a history of large hail and damaging winds is moving across northwest Iowa currently and is expected to remain severe through the morning hours. This watch will be in effect until 11:00 AM and cover the areas shown below:

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Morning Bow Echo

Thunderstorms cleared the state during the overnight hours, but not before providing several reports of hail and damaging winds as well as a tornado report in northeastern Iowa during yesterday evening.

Early this morning there is a bow echo that is entering northwest Iowa with the potential for damaging winds in excess of 60 mph. This storm has had a history of damaging wind gusts as well as marginally severe hail. The bow echo is a line of storms extending from near Beresford, SD southwards to near Pender, NE; and is moving east/northeast at 35 mph. A Severe Thunderstorm Watch has been issued for portions of northwest Iowa until 9 am for this line of thunderstorms.

This line of storms does appear to travel towards my location, thus will plan for its' arrival between 8:30 and 9:00 AM with the likelihood of a photogenic shelf cloud.

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Severe Weather Update #2 - June 17

The weak boundary is responsible for several ongoing tornadic storms over north-central and northeast Iowa as well as southern Minnesota. Currently Chickasaw county has a tornado warned storm that has produced a tornado before within the past hour, and this storm may continue to produce tornadoes as it moves to the southeast. Another, perhaps more dangerous storm, is moving into Mitchell and Howard counties in Iowa. This storm has produced a large and dangerous tornado that is responsible for injuries across Austin, MN and nearby areas. These storms are likely to continue to be tornadic in nature for at least the next hour or two. After which the instability may begin to weaken in those areas and we may see the storms weaken... Persons in those areas should be very aware of the conditions and take shelter if any storms approach.

Additional thunderstorms have fired across northeast Nebraska and into southeast South Dakota. Given environmental conditions ahead of these thunderstorms, they are likely to maintain a severe weather threat into the overnight hours. Areas of west-central and northwest Iowa are likely to see these storms as they have the potential to produce significant severe weather. Additional updates are likely as storms continue to threaten areas of the state.

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Severe Weather Update #1 - June 17

Severe and now tornadic thunderstorms are ongoing with the stronger warm front located along the Kansas/Nebraska border. Additional storms are likely as we continue through the afternoon and eventually congeal into more of a cluster or MCS of storms moving into west-central and southwest Iowa.

The other area of concern for severe weather, including tornadoes, will be over northwest/north-central Iowa where a convergent low level boundary associated with a weak low pressure system over South Dakota may trigger thunderstorms this afternoon/evening. Latest analysis indicates this wind shift is becoming very defined with strong instability along and east of the boundary. Effective wind shear values above 40 kts will support supercells when initiation occurs, and likely support tornadic storms through the evening hours.

I plan on chasing any development along this wind shift and weak boundary in northwest Iowa, thus stay tuned for additional updates!

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Severe Weather Potential - June 17

The potential is there for significant severe weather across the western half of Iowa this afternoon and into the overnight hours. All modes of severe weather appear possible, including damaging winds, very large hail, and tornadoes. There are two areas of concern for severe weather today, both of which cover western Iowa...

The first and most likely concern will be over much of western Iowa, and likely be during the late evening or overnight hours. This severe weather threat will likely be for damaging winds and large hail, although a risk of tornadoes will exist, a more linear nature of thunderstorms may be expected. These thunderstorms will evolve from central Nebraska this afternoon as they initiate due to a shortwave and frontal system interaction. As the thunderstorms continue to evolve eastward they are likely to congeal into a more linear MCS capable of large hail and damaging winds as they enter into western Iowa.

Another threat for severe weather will exist during the afternoon/evening hours over mainly northwest Iowa, as well as southwest Minnesota. Similar to yesterday afternoon over South Dakota, a weak low pressure system in conjunction with a trough of low pressure and low level convergence may lead to thunderstorm development along a weak wind shift line. With even higher temperatures and dew points this afternoon yielding even higher instability amounts this will come as no surprise to see even stronger supercells off of this setup. These storms will be capable of all modes of severe weather through the evening hours, but similar to yesterday they should begin to weaken after sunset.

Additional updates are likely this afternoon as the severe weather threat evolves, I am watching the potential across northwest Iowa for the tornadic supercells similar to yesterday...

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Severe Weather Update #1 - June 16

Although severe weather is not immediately affecting any portion of the state, ongoing and developing thunderstorms appear to be moving towards northwest Iowa and may enter the state in the coming hours. The most immediate danger would appear to effect Plymouth and Sioux counties in Iowa over the next two hours. The NWS in Sioux Falls has extended the tornado watch that was in effect for eastern South Dakota to include those counties that are in the direct path of a strong tornadic supercell that has had a history of producing tornadoes, some of which have appeared to be strong, over southeast South Dakota. Currently this tornadic storm is east of Yankton, SD and is moving southeast at 30 mph. This path would likely effect Vermillion, SD and eventually towards Sioux City, IA by approximately 10:30 PM. While the tornadic threat may not continue through this time, it would appear that at least damaging winds and large hail would be an issue for areas of Plymouth and Sioux counties.

Additional updates are possible if this continues on its' track towards northwest Iowa.

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Severe Weather Threat - June 16

While some thunderstorms move across parts of central/eastern Iowa this morning, and some lingering showers/cloud cover continue across western Iowa, we are likely to see clearing skies and an increased chance of thunderstorms once again this afternoon/evening and potentially into the overnight hours. Temperatures not only today, but through the remainder of the week are likely to rebound nicely after morning convection and/or cloud cover. Highs into the 80s and 90s over the state are likely through Thursday...

A weak surface low is positioned across central South Dakota this morning, and is likely to only move slightly as we continue into the afternoon hours. Two troughs of low pressure are likely to extend from this low pressure system and create a moderately unstable warm sector for this afternoon across eastern Nebraska, eastern South Dakota, western Iowa and other adjacent areas. Moderately instability combined with a weakly capped environment should create ample development by the afternoon hours along both troughs in SD/NE and perhaps across Minnesota and extreme northern Iowa. While moderate bulk shear is present across the entire warm sector, directional shear appears to be limited over SD/NE/MN/IA where development is likely. Thus it would appear as if the main threats of severe weather will be for large hail and damaging winds with the strongest and more organized storm clusters this afternoon. Additional update are possible if the severe weather threat warrants...

The severe weather threat will likely continue for the northern plains on Wednesday, and continue through Friday. Both Wednesday and Thursday have warm fronts that will likely be positioned across Iowa or just south of the state warranting the risk for severe weather. Thursday will also have a cold front finally pushing eastward over the plains states with an increased risk of severe weather; a similar threat exists on Friday. Additional updates on these risks as the week continues.

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Overnight Thunderstorms

Severe and tornadic thunderstorms continue to move across much of the northern and central plains states. Some of these storms may enter the western portions of Iowa within the next few hours, mainly over southwest Iowa where a Severe Thunderstorm Watch is in effect. Currently, a line of thunderstorms is moving into southeast Nebraska and will continue to move northeastward into southwest Iowa likely by 10:30 PM capable of large hail and damaging winds. Other storms over central Nebraska and South Dakota will likely congeal into more of an MCS as the low level jet continues to increase and organize storms and produces additional development. These storms are not as likely to be severe, rather with a continued heavy rain threat over parts of the state which saw heavy rains over the past few days.

Thunderstorms will likely linger across the state tomorrow, with additional development of severe/tornadic thunderstorms possible to move into the state during the evening hours. Additional updates on tomorrow's severe weather threat over the southwestern half of the state is likely tomorrow morning.

The forecast will continue to warm up as well as moisten to allow more chances of thunderstorms later in the week, with another round of severe weather being likely on Thursday across much of the state.

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Warming Weekend

After below normal temperatures and an end of the week that was both cool and wet we will begin a weekend that will start us on a warming trend! Rainfall totals across the state appeared heaviest across western Iowa where just over an inch fell in areas such as Sioux City and LeMars. Other areas of the state, especially the southeast, did not see nearly as much with only a few hundredths to a few tenths in the heaviest areas. Expect a few lingering showers over central and eastern Iowa tonight, and mainly cloudy skies over those same areas while parts of western Iowa begins to see some clearing skies.

Lows overnight tonight from near 50 in the northwest to near 60 in the southeast. Partly cloudy skies will prevail for Saturday, and with the sunshine we'll see highs in the mid 70s throughout the entire state. Saturday night will remain partly cloudy across the state, with increasing clouds over the west as we near sunrise on Sunday. Low temperatures will range from the lower to mid 50s from northeast to southwest. A weak frontal system will approach the state from the southwest on Sunday, bringing in more chances of showers and an isolated thunderstorm over the southwest half of the state on Sunday and Sunday evening. Highs on Sunday should be fairly consistent across the state near the mid 70s; with overnight lows in the mid to upper 50s from northeast to south. Our frontal system stalls out and begins to become diffuse which will decrease our chances of showers overnight on Sunday.

In the long range, it would appear that mainly zonal flow with embedded shortwaves will prevail over the plains states through the week. This will bring us off and on showers/thunderstorms throughout the week. Some slight ridging is expected to begin towards next weekend, with this expect an increase in temperatures as we near the upper 80s and finally the 90s across parts of Iowa. More details on this true southern warmth in next weeks' forecast updates.

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TWISTEX & Other Chasers

Today was forecasted to be another potentially significant day of severe weather with an increased tornado potential across the plains states. Unfortunately for all of the groups out there that are doing research, from my TWISTEX buddies, to VORTEX2, and to all of the other chasers out there, today once again turned to be a big disappointment from a tornadoes standpoint.

The tornado reports today came across eastern Kansas during the early afternoon storms that were likely triggered and aided by the morning MCS. Other reports came across the high plains of Colorado where little risk was expected, and even a stray report in Nebraska that was a very brief and likely a landspout. Sunday was expected to be a strong day for thunderstorms and tornado potential, while the thunderstorm aspect wasn't a disappointment with hail larger than 5 inches in diameter, the tornado reports that may have verified were all brief and weak. This year is the lowest since 2005 as far as tornado reports, and is nearly 200 tornadoes below the last 4-year average. While there are plenty of chasers who have still had a good year, most are still very disappointed in the year thus far.

Thus, I am not too disappointed that I have had to miss this years' activities due to the birth of my first little boy. Here's to a hope that we can continue the mediocre year well into June and into this fall over the northern plains.

While I'm on the context of other chasers including TWISTEX, I would like to give my little shout-out to the group that is chasing as a part of the Discovery Channel Storm Chasers crew. TWISTEX is being displayed as a professional and pure scientific research group, as that is what they are! Tim Samaras, Dr. Bruce Lee, Dr. Cathy Finley, and Tony Laubach among others have had some luck this year; they were able to have a successful mission out in Wyoming last week as well as many others. Be sure to follow their updates as I post them on their website: http://www.twistex.org

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