Severe Plains

Today’s Severe Threat & Flood Update

// June 9th, 2011 // No Comments » // General Forecast, General Information, Severe Weather, Severe Weather Forecast, Storm Updates

A warm front currently positioned across parts of eastern Kansas and over northern Missouri will become the focus for additional thunderstorm development this afternoon as it retreats northward slowly. Ample instability will be present along and north of the boundary with 2000-3000 J/kg of mixed-layer CAPE to support the potential for large hail and damaging winds with any thunderstorms that do develop over areas of far southeast Nebraska, northeast Kansas and adjacent areas of northern Missouri and southern Iowa. An area of increased low level shear appears to exist over the ‘four corners’ of these states where a weak low pressure center may exist to allow backed low level flow and sufficient turning to support a tornado threat with any isolated storms this evening. Storms will likely develop into one or more clusters as they move east across Iowa/Missouri and transition into a damaging wind and marginal hail threat…

Additional thunderstorms may develop southward along dryline in eastern Kansas and perhaps into Oklahoma and Texas as well. With meager flow aloft these will likely only support damaging winds and perhaps some large hail at times with better severe threat the closer to the corners of NE/IA/KS/MO.

Flooding Update: Precipitation over the next few days over the Missouri River Basin will likely increase potential for flooding along the river and pose a definite risk of flash flooding with areas potentially receiving several inches of rainfall. The Gavins Point Dam is expected to reach its’ peak outflow of 150,000 cfs on June 14 based on current forecasts from the USACE, this peak flow then looks to continue through the month of July and likely longer. Flooding is already occurring with roads now beginning to close and several cities sandbagging efforts likely to be tested by this weekend and then especially next week as levels continue to rise.

2011 Missouri River Flooding

// June 5th, 2011 // No Comments » // General Forecast, General Information, Severe Weather, Storm Updates

Thanks to an extensive above average snowpack over the Missouri River basin and record rainfall over areas of eastern Montana and the Dakotas as of late, not to mention other areas of heavy rainfall further south along the Missouri River, the US Army Corp of Engineers is releasing water from every reservoir along the river for the first time in history. This release is also the largest release for several of the dams since they have been built, in fact, Gavins Point Dam in South Dakota will nearly double their previous record release from 2007. These releases will yield well above flood stage river levels from mid-June through July and likely into August over the Dakotas, Nebraska, Iowa, Kansas and Missouri. Despite levees that protect some areas of farmland and even towns along/near the river the water levels are expected to be so high that levees will be rendered ineffective against such high stages. Multiple towns near the river are already in the process of evacuating with the likelihood of not returning for at least 2 months! Other towns are beginning their battle against the water by piling up sandbags to reinforce levees or protect other areas from the rising waters. Other major cities such as Omaha will be watching the water and their levees closely, as any breach in those levees could result in catastrophic flooding for the city.

With such high water levels expected based upon normal precipitation and the record releases from reservoirs, any above average precipitation that occurs over the next couple of months in these areas will also need to be closely monitored. I will be updating information about the river whenever possible over the next few months, with the hope of even going and visiting a few areas nearby that could see or are having flooding. For now, here is a few helpful links:

Omaha US Army Corp of Enginners – Inundation Maps
Kansas City US Army Corp of Enginners – Inundation Maps

I will also be providing more frequent, but short, updates and links on Twitter @SeverePlains

March 22 Severe Weather Update #1

// March 22nd, 2011 // No Comments » // Severe Weather, Severe Weather Forecast, Storm Updates

The Storm Prediction Center has issued a discussion indicating that a tornado watch will likely be issued by 3pm for parts of southeast Nebraska, southwest Iowa, northeast Kansas and northwest Missouri. Recent satellite observations indicate a weakening layer of inhibition across north-central Kansas along and ahead of a dryline. This weakening inhibition combined with quickly rising temperatures has allowed for nearly 1500 J/kg of surface based instability to become present. Bulk shear values greater than 40 knots indicate that wind shear is favorable for suprecells, likely within a broken line of convection that will initiate shortly after 3pm. Low level shear values are increasing ahead of the dryline, indicating the potential for tornadoes may exist as storms mature and move eastward late this afternoon…

People in this area should pay close attention weather conditions this afternoon and evening with strong to severe thunderstorms and perhaps a few tornadoes being possible.

Jan. 31 – Feb. 2 Winter Storm

// February 2nd, 2011 // No Comments » // Severe Winter Weather, Storm Updates, Weather Recap, Winter Weather

The winter storm across the Central Plains is winding down with generally light snow still ongoing over parts of Missouri and Iowa. The winds however are maintaining intensities above 20 mph sustained with gusts to near 40 mph still late tonight and that will likely continue into the afternoon today. This will keep the blowing and drifting snow ongoing and likely continue the hazardous travel conditions across a large portion of the Plains. This storm will continue to cause problems for areas of the Midwest, but the biggest impacts with blizzard conditions appear to be subsiding as this storm wraps up and occludes.

Snowfall began just after sunrise on Monday across Kansas City and continued to increase throughout the morning. Some of the heaviest snow came during the mid-afternoon as snowfall fell at a rate of 2-3 inches per hour. Total snowfall amounts at the moment appear to be 9-14″ across the Kansas City Metro, with the lightest amounts north and heaviest south and especially southeast. As indicated, a swath of 20″ of snow did fall with this storm system from far southwest Missouri through areas of west-central, central and into northeast Missouri with drifts several feet high. Despite the numerous warning and attempts to warn public of the dangers there were still a large number of accidents across Missouri, with I-70 being closed across the entire state Monday evening.

I’ll provide links to all of the snowfall maps and summaries from local weather services offices once they become available. I also have a time lapse of the winter storm as seen from Lenexa, KS that I will post sometime today or perhaps tomorrow!

1/9-11 Winter Storm Update

// January 10th, 2011 // No Comments » // Severe Winter Weather, Storm Updates, Winter Weather

Snow has spread eastward overnight into central Iowa and northwest Missouri where several inches of snow has already accumulated over these areas. Many more hours of snow is still expected for these areas, with significant snowfall accumulations still appearing likely. Here in Kansas City a widespread 2-3″ of snow has fell by dawn, with around 12 more hours of steady snow expected. Total accumulations should range from 6-10″ by the time the steady snow tapers to flurries this evening…

The snow should continue to spread eastward today, through Iowa and Missouri by this evening and into Illinois. While snow accumulations are not expected to be as high over eastern portions of the states, accumulations will still be high enough to cause widespread travel problems and likely cause many cancellations of evening activities and at least delay Tuesday’s start to the day for many. With a bit of an increase in winds on Tuesday this fresh snow will also blow and drift during the day, leading to continued travel problems.

With roads already snow covered, and only becoming worse with time it is best to avoid travel if possible. Multiple wrecks have already occurred yesterday and this morning over the snow covered roads…

Current Road Conditions:

Nebraska – http://www.511.nebraska.gov/atis/html/index.html
Iowa – http://hb.511ia.org/main.jsf
Missouri – http://www.modot.org/tim/
Kansas – http://511.ksdot.org/KanRoadPublic_VE/Default.aspx

January 9-11 Winter Storm

// January 9th, 2011 // No Comments » // Severe Winter Weather, Storm Updates, Winter Weather

A quick afternoon update for the upcoming Winter Storm(s) that will affect much of the Central Plains and Southeastern United States over the next couple of days. Snowfall is already occurring across parts of eastern Oklahoma and Texas, as well as Arkansas and Louisiana where the southern storm system will continue to push east across the Southeast U.S. leaving several inches of snow and some freezing rain along the Gulf Coast. Even a couple inches of snow over these areas will be enough to put a standstill to normal life in these areas, thus expect dangerous travel conditions across these areas.

As for the Plains states, the northern disturbance has already saturated the air across Nebraska, western Iowa and points northward with snow ongoing. As we head into the overnight snow will continue to spread east and south across areas of Kansas and into western Missouri by dawn. The snow will continue through the day Monday, progressing eastward across Missouri and Iowa into areas of Illinois by Monday night. While a few brief periods of heavy snow may be possible with waves of frontogenesis and upper level support, most snowfall will come at a light to moderate intensity over a long period of time. With the lack of heavy snow rates, most National Weather Service offices have opted for Winter Weather Advisories instead of Winter Storm Warnings. For the Kansas City area, snowfall will begin during the late overnight hours and continue through the day on Monday with snowfall accumulating slowly but surely through Monday afternoon and evening. Snowfall should then begin to decrease Monday night, with lingering flurries and then some blowing and drifting snow during the day on Tuesday. Total snowfall accumulations for the Kansas City Metro are likely to be 5-8″ from east to west, with isolated amounts of 10″ possible over the northwest parts of the metro.

The heaviest snowfall accumulations are likely to be over central and eastern Nebraska, western Iowa, northern Kansas and northwest Missouri; where snow totals of 8″ or greater will be possible. Some locations may even see snowfall totals greater than a foot with snow persisting for more than 24 hours! I’ve thrown a few snowfall accumulation graphics straight from the NAM and GFS below, this mornings’ 12z runs on the left with the 18z Noon model runs on the right; the NAM is first, then the GFS.

An Impressive End to 2010…

// January 1st, 2011 // No Comments » // General Forecast, General Information, Severe Weather, Storm Updates, Weather Recap, Winter Weather

And an interesting beginning of 2011 for that matter…

A deepening surface low and strengthening storm system over the Northern Plains on Friday morning led to widespread snowfall across areas of Nebraska, Minnesota and the Dakotas. Meanwhile, the strong push of warm air that led to record temperatures on Thursday created just enough instability to combine with the strong wind fields to create severe weather across areas of Missouri, Illinois, Arkansas and now over areas of the Southeast and Tennessee Valleys’ this morning.

While the snow was once again impressive across areas of the Dakotas and Minnesota, the larger story with this system ended up being the severe weather with multiple tornado reports across the Central Plains. Thunderstorms that developed during the late overnight and early morning hours continued, with additional development also occurring during the morning hours over south-central Missouri. While overall instability was marginal, the amount of shear in the lowest 1 kilometer was very impressive in both directional and speed. This ended up being favorable for squall-line storms that were also capable of producing tornadoes, many of which were very fast moving and short-lived. Multiple reports came in from the a line of storms that passed through Fort Leonard Wood, then Rolla and then to the St. Louis metro along the I-44 corridor during the late morning and early afternoon on Friday. Unfortunately, extensive damage was reported in each of these areas with homes and businesses among property being damaged. There were also multiple injuries and deaths with the storms as they rolled mobile homes, toppled trees, power lines and did extensive damage to houses.

The Springfield, MO NWS has confirmed at least 4 tornadoes across their county warning area. One of which is unrated at the moment, two of which have been rated EF-1 and the fourth which occurred across Fort Leonard Wood an EF-3. The damage surveys are still being completed, and more information will be made available from these tornadoes and will be located on their page: SGF Dec. 31 Tornadoes

The St. Louis, MO NWS office has begun their surveys as well, with as many as six potential tornadoes having occurred. The most extensive of which occurring in Sunset Hills, MO just west-southwest of St. Louis City just before Noon and has preliminarily been rated at least EF-3, but may perhaps been an EF-4 upon completion of the survey. Their final analysis will be available by Saturday afternoon at their page: LSX Dec. 31 Tornadoes

Severe weather continued across parts of Illinois before settling down as it outran any instability and moved away from the near-stationary storm system across the Dakota/Minnesota borders. Other severe thunderstorms developed across Louisiana and Mississippi though, with multiple tornado warnings and a tornado watch continuing into the early morning hours of the new year across Alabama. Meanwhile, the cold air continues to push in behind the strong cold front with temperatures plummeting across Missouri. St. Louis was in the 60s when tornadoes occurred near Noon on Friday, but are now dropping below freezing. Temperatures are in the single-digits and even below zero across the Northern Plains as the low pressure continues to occlude. Winds are still very gusty, creating blizzard conditions to the north and west of the surface low pressure where snow is still falling and new snow over the past 48 hours is blowing around.

Once we get passed this first day of the new year, it would appear that the weather quiets down for at least the first half of next week. A few weak disturbance may lead to some light snow, however nothing significant looks to be on the plate for any areas of the Plains perhaps through the entire first week of January 2011.

Lowest Pressure from Extratropical Cyclone!

// October 26th, 2010 // No Comments » // General Information, Severe Weather, Storm Updates, Weather Recap

That is correct, the low pressure system that has ‘bombed’ out over northern Minnesota today has now reached a minimum pressure that is the lowest in known US History. The unofficial mark is currently at 956mb, 28.23 inches, over northeastern Minnesota and is now finally beginning to steady-off in its’ strengthening. Wind gusts associated with the surface low have been sustained of 35-45 mph with gusts well into the 50s and even in the 60s of mph this afternoon. Other wind gusts of 70+ mph have been reported in association with ongoing thunderstorms as a results of this strong storm system, as well as short-lived tornadoes on the leading edges of bow echoes.

Here are just two of the impressive surface maps from this afternoon:

Significant Iowa Flooding

// August 11th, 2010 // No Comments » // General Information, Severe Weather, Storm Updates, Weather Recap

Thought I would provide a brief update regarding some of flooding that is ongoing over areas of Iowa. You can look back at a previous post regarding a recap of July and its’ flooding woes due to copious amounts of rain that fell over much of the Central and Northern Plains. While we saw a brief break with the hot weather, several thunderstorm complexes have trekked across the state in the past few days and have once again wreaked havoc on local streams and rivers. Flooding occurring in parts of central Iowa, including Ames and Iowa State University as well as parts of the Des Moines metro saw rapidly rising waters last night and through today. Several locations in Ames are approaching or have already exceeded the record levels, many of which occurred during the devestating floods in 1993. Numerous roads, including I-35 and Highway 30 near Ames have been closed and there is potential that I-80 could also be closed later due to rising flood waters; along with dozens of local highways and rural roads. You can view several images and videos of the flooding by going to any local media outlet in the Des Moines area, and see the latest regarding Iowa State University and its’ flooding at their website (www.iastate.edu). The Cyclones football team held its’ practices today by lifting sandbags to try and hold off the water from entering a few campus athletic facilities. You can see a few of there pictures and others, including the flooding of Hilton Coliseum at the athletics website (www.cyclones.com).

Thankfully it currently appears that the water rises will be short-lived, with waters beginning to recede already this afternoon. However, a cold front is expected to push into the area Thursday evening which may once again bring widespread thunderstorms to the state on Thursday night, Friday and Friday night before ending once again. I’ll post an entire recap on the flooding including rainfall amounts, river levels and some links to photo albums, etc. sometime this weekend as the flooding begins to subside (hopefully).

More Thunderstorms… At least for some

// June 26th, 2010 // No Comments » // General Forecast, Storm Updates

The boundary responsible for the multiple tornado warned storms over southern Minnesota and northwest Iowa, and the severe squall line that moved into Central Iowa will once again be the focus for thunderstorm development Saturday afternoon over areas of the Northern Plains. The area of interest will likely be near the intersections of Nebraska, South Dakota, Minnesota and Iowa as a low pressure center over south-central South Dakota is able to back winds to the southeast. Once again very strong instability will be present with temperatures nearing 90 degrees and dew points in the mid 70s and while deep layer shear is expected to be slightly weaker, 30-45 kts, the low level turning will maintain the threat for tornadoes along with very large hail and damaging winds. The virtual chase target for Saturday’s storms will be Alexandria, SD…

The front will then slide southeast through the overnight hours on Saturday, with a line of strong to potentially severe thunderstorms continuing into parts of Nebraska and Iowa. Thunderstorms are expected to arrive into parts of northeastern Kansas and northern Missouri during the late overnight hours, and near dawn to the Kansas City area. As the front continues to the southeast, any upper level winds that would support strong thunderstorms will stay to the north of the area. Combined with a fairly lackluster surface wind field and convergence, the frontal passage may be quite similar to the previous one across Missouri where only scattered convection may initiate during the afternoon/evening with a generally limited severe weather potential. Expecting the front to be pushed south of the Kansas City area by later Sunday night, leaving the area in a fairly seasonably warm and dry air mass for much of the week next week. Long range models continue to indicate a significant western ridge to build along the Rockies, promoting weak flow aloft through mid-week next week. The ridge may slowly drift eastward to the Plains by this time, and should weaken and return to at least zonal flow by the July 4th weekend. Of course the return to zonal flow will likely promote an increased chance of thunderstorms somewhere along the Plains, but until then expect to see a very nice warm and dry air mass over much of the Plains states.