Severe Plains

Severe Weather Potential

// June 19th, 2011 // No Comments » // Severe Weather Forecast

A quick update this morning on the next two days of severe weather potential across areas of the Central Plains, where two potentially significant severe weather outbreaks are possible. Today’s severe weather threat will be maximized across southern Nebraska, northern Kansas and into northwest Missouri and southeast Iowa where a warm front will be draped across. A strong upper level trough will begin to dig across the High Plains this evening, promoting thunderstorm develop over western Nebraska/Kansas. Additional thunderstorms will be possible along the warm front as well where convergence and strong instability will help erode any inhibition. Thunderstorms will likely produce large hail and damaging winds well into the overnight as they continue eastward towards the Missouri River. Tornadoes will also be a definite possibility along and just north of the warm front where strong instability combines with backed low level winds…

Tomorrow (Monday June 20) is also shaping up to be a potentially significant severe weather day across eastern Nebraska and western Iowa where potentially strong tornadoes are not out of the question. A surface low will likely be located over far eastern Nebraska by Monday evening, with a warm front draped eastward across Iowa; while a dryline and cold front will be across eastern Nebraska/Kansas. Strong to extreme instability will likely be present across the warm sector where temperatures will be in the 90s along with dew points well into the 70s in some locations. A closed upper level low will continue to deepen through the afternoon with a unseasonably strong mid-level jet streak of 60-70 knots moving across the region. Strong wind fields will promote bulk shear values of 40-55 knots along with strong low level turning to promote tornadic supercells with any storms that do develop. Along with tornadoes, strong wind fields will likely promote damaging winds and strong instability will support large hail. Further south along the dryline/cold front into Kansas, thunderstorms will also be likely during the evening and overnight as strong height falls and cold air advection erode away a strong capping inversion. Significant mixing throughout the afternoon will likely yield very high LCL’s, thus most storms will likely be elevated in nature with the main threat being large hail.

I’ll provide an update later tonight on the potential for Monday’s severe weather…

Severe Weather & Other Headlines

// June 17th, 2011 // No Comments » // General Forecast, General Information, Severe Weather, Severe Weather Forecast

An active period of severe weather will likely continue through the weekend and into early next week as a frontal boundary continues to wander back and forth over the Central & Northern Plains the next couple of days. It appears that a fairly robust trough will come into the Central US early next week, prompting the potential for perhaps significant severe weather on Monday and Tuesday over areas of Nebraska, Iowa, Kansas and other adjacent states. Each day will bring its’ challenges in pinpointing the exact location of the severe weather risk as overnight convection and remnant boundaries give way to localized areas of both increased and decreased probabilities for additional afternoon and evening thunderstorms. Today’s risk is over a large areas of the Plains where sufficient instability and marginal shear will give way to several clusters of thunderstorms by this evening across areas of Nebraska, Iowa, Kansas, Missouri and even further east into Illinois. The main threat with these storms will be large hail and especially damaging winds as storms develop cold pools and begin to gust out as they move south/east.

Tomorrow’s severe weather threat will be centered over the heart of the Plains, over Kansas, Missouri and even Oklahoma where very strong instability and moderate shear will be present. Although strong inhibition is likely with 700hPa temperatures rising well above 12C, the strong instability should give way to at least a few storms along the dryline in southern Kansas and Oklahoma. These storms will likely expand as they move north and east; with continued strong instability and increased shear likely to increase the potential for both large hail and especially damaging winds.

Sunday’s severe weather risk will likely be further northwest as a low pressure system begins to develop off the lee of the Rockies and associated surface fronts are pulled north and west. Shear will likely begin to increase with the upper level trough beginning to push across the Rockies, thus a high plains severe weather threat seems highly likely at this point.

Both Monday and Tuesday appear to be very favorable for severe weather given the upper level trough and closed low that will likely move across South Dakota. A warm front will likely be draped over South Dakota and perhaps further east into Minnesota or Iowa; a strong dryline will also be present from the low over southern South Dakota southward into Oklahoma and Texas. With strong deep layers shear and instability, tornadic supercells seem like a good probability over portions of the Northern and Central Plains. I’ll continue to provide some updates over the weekend as more details get hashed out…

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A couple of other headlines of interest:

I hope to get a few images of our vacation to Branson, MO up this weekend, including a few of Joplin as we passed through on Business 71 and some of a cave we visited while we were there.

The Missouri River continues to flood with rainfall continue to add to localized problems as runoff literally has no where to go along the river. The flooding has closed down several spots along I-29 in both Iowa and northwest Missouri to go along with numerous local roads. While the flows coming out of each dam continue to be at record levels, any above normal precipitation will exacerbate the rising river. Levees are now the key thing to watch, as areas which are holding off the river are being protected only by those levees. Any drastic increase in flow due to extreme rainfall over not only the next week, but the next month and longer could pose additional risks to those along the river.

An interesting story from the Joplin Globe showing how at least 57 people died during the Joplin tornado while in their homes and perhaps even taking cover from the storm like they are supposed too.

June 9, 2011 Severe Weather Update

// June 9th, 2011 // No Comments » // Severe Weather, Severe Weather Forecast

A tornado watch has now been issued to include much of northeast Kansas and northwest Missouri as well as adjacent portions of southeast Nebraska and southwest Iowa until 10pm. An warm front and outflow boundary is currently situated across northeast Kansas into northwest Missouri; from near Salina, KS to just north of St. Joseph, MO to just north of Columbia, MO. Very strong pressure falls on the order of 3mb over the past 2 hours near Kansas City have resulted in strong backed winds at the surface, south-southeast 15-25 mph with even higher gusts. These wind have resulted in bulk shear values of 35-50 knots, although 0-1km shear values are relatively low at the moment increased flow just above the surface this evening should strengthen these numbers to sufficient levels. Instability values currently 2000-3000 J/kg of both surface based and mixed-layer also show the potential for large hail and some damaging winds.

This combination of these backed low level winds and moderate instability also continue to promote a good possibility of supercells capable of producing tornadoes. Storm initiation seems likely between 4-5pm with strong convergence noted along the warm front and especially over northeast Kansas near the triple point. Storms will likely become severe quickly with the potential for tornadoes continuing into the evening before thunderstorms evolve into a more cluster or linear segments with increased potential for large hail and wind gusts.

The initial thought this morning of a target along the Highway 36 corridor in northeast Kansas continues to look favorable as this area will be along the warm front where strongest shear values coincide with moderate instability.

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.

Summer Arrives!

// May 31st, 2011 // No Comments » // General Forecast, Severe Weather Forecast, Weather Recap

A briefly impressive cold front moved across portions of the Central Plains last night, initiating a line of severe thunderstorms across central Nebraska and Kansas as well as areas to the north. This front is now moving across the Great Lakes region today with the potential for additional severe weather, meanwhile it’s beginning to fade away across areas of Missouri. This front will glide back to the north tomorrow as a pseudo-warm front and perhaps bring a few showers/thunderstorms to the Kansas City and surrounding areas. The best severe weather threat tomorrow will be over the adjacent corners of South Dakota, Nebraska, Iowa and Minnesota where the potential will exist for some severe thunderstorms capable of very large hail and damaging winds.

The bigger story for the best of the week will be the building upper level ridge over the Central United States and the retrograding high pressure system that will push back into the Central Plains for the latter half of the week. These two features along with continued southerly flow will allow summer to make its’ first extended appearance with warm and humid conditions expected for the rest of this week and well into next week as well. A few weak disturbances look to begin to break down the mid-level ridge by this weekend and may promote scattered thunderstorm activity. Temperatures look to range from the upper 80s to mid 90s over much of the Central Plains, with even higher temperatures expected over areas of western Kansas where the century mark will definitely be possible.

Organized severe weather across the Central Plains looks to be rather non-existent for at least a week, with the best upper level flow promoting better thunderstorm potential across the far Northern Plains and southern Canada. Also, stronger flow aloft and the southerly flow at the surface will likely yield several days of thunderstorm potential in the High Plains areas too.

Welcome to June and mother nature says welcome to summer!

Severe Weather Outbreak Possible; Are YOU Prepared?!

// May 23rd, 2011 // No Comments » // Severe Weather, Severe Weather Forecast, Storm Chasing, Weather Recap

A tragic scene unfolded yesterday in Joplin, MO as a strong tornado destroyed numerous buildings and lives. Other tornadoes also caused devastation across areas of Oklahoma, Kansas, Missouri, Minnesota, Iowa and Wisconsin! There are numerous areas to see the latest information about these tornadoes and damage, so I won’t re-hash that here.

Rather, I’ll inform you that conditions are becoming prime once again for severe and tornadic thunderstorms this afternoon and evening across areas of Oklahoma and adjacent portions of southern Kansas, southwest Missouri and western Arkansas into the overnight. Please stay tuned to your local weather information source this evening…

Of even greater concern is the potential for tomorrow (Tuesday, May 24) as another upper level disturbance moves onto the Central Plains and promotes the strengthening of a surface low over central Kansas. Abundant low level moisture and very warm temperatures will yield strong to extreme instability across this region with mixed layer CAPE values of 3000-4000 J/kg. A strengthening wind field near the surface low and an early and strong low level jet will also yield very strong low level wind shear across not only areas of central Kansas/Oklahoma along the dryline, but even further east over the rest of Kansas/Oklahoma and even into Missouri/Arkansas. Such combinations appear to leave the area primed for a potentially significant severe weather outbreak with not only significant large hail, damaging winds; but the potential for strong and damaging tornadoes will be prevalent.

Those in this area need to watch conditions closely, especially with thunderstorms beginning early in the afternoon, perhaps 1-3pm and progressing eastward through the remainder of the afternoon/evening. It appears to be an afternoon, evening and even overnight filled with severe weather and all eyes need to be on the skies. With such prolific wording already about tomorrow, now is the time to become prepared and know what you are going to do tomorrow if severe thunderstorms are to strike.

I will try to provide brief updates on the blog as much as possible, otherwise please follow me on Twitter (@SeverePlains) for additional updates/information.

Another Week… Another Update… Another Failed Setup

// May 21st, 2011 // No Comments » // General Forecast, Severe Weather, Severe Weather Forecast, Storm Chasing

I figured it was about time for another update; I know, I’m getting bad at keeping things active here on the blog. The past few days were being looked upon as the first good setup for the true chase terrain in May, that is those areas along and west of I-35 in Kansas, Oklahoma and even the Texas panhandle. A large trough was expected to close off just west of the Plains with sufficient moisture return leading to a very unstable environment over these areas. Shear was sufficient, especially on Thursday, which was more than adequate to support the potential for tornadoes over these areas as well. However, once again in 2011 mother nature has failed us with very few tornado reports and very un-photogenic ones at that. The closed low remained too far to the west, allowing for more southerly flow throughout the mid-levels and essentially producing a setup that while was supportive of thunderstorms was not supportive for multiple tornadic thunderstorms.

Thunderstorms that developed along the dryline moved nearly due north, essentially ruining the atmosphere along the dryline with more stable air. While this may not have been an issue given storm development from north to south, with such weak inhibition in place storms actually developed south to north along the dryline on Thursday. Regardless, what was once looked upon as a potential tornado producing setup has appeared to go by the wayside at the moment. Thunderstorms on Friday were nearly non-existent over the prime chase territories of Kansas with only a few cells able to go severe warned with marginally severe hail. The only tornadic storms of the day occurred over far eastern Oklahoma, northeast Texas and Arkansas which is far from favorable areas to chase.

This closed upper level low is going to slowly trek eastward over the weekend and early next week, with several mid-level waves ejecting out from it and allowing for several rounds of thunderstorms over the Central Plains. Severe weather is definitely not out of the question over the weekend, with scattered strong to severe thunderstorms expected each evening and into the overnight. While the tornado threat may be a bit lower, the more scattered nature of these thunderstorms may prove to be better than the storms earlier this week.

As for the Kansas City area, a few rounds of thunderstorms this week have produced quite a bit of rain over the area. However, we have lacked any organized convection. That may change over the weekend as additional development nearby or just west may lead to more organized strong to severe convection as they cross the Kansas and Missouri border. The current outlook for Saturday does indicate the potential for some large hail given the abundant instability present within the hail growth region, as well as a damaging wind threat given a layer of dry air both near-surface and aloft. The tornado threat appears rather meager for most areas however given the lack of significant 0-1km shear, however subtle boundaries from earlier convection could lead to a localized higher threat.

I may provide brief updates on Twitter (@SeverePlains) if necessary later today for the potential for severe weather in/near the Kansas City Metro…

April 3 Severe Weather Recap

// April 5th, 2011 // No Comments » // General Forecast, Severe Weather, Severe Weather Forecast, Weather Recap

Thunderstorms developed explosively shortly before 6pm Sunday evening, both along the cold front in Iowa and northern Missouri and behind the cold front in eastern Kansas. Instability was not a problem with thunderstorms, as they quickly organized and developed into severe-warned storms with the capabilities of large hail and damaging winds. Thunderstorms across Iowa did display some low level rotation at times, however the nature of the storms being forced along the cold front did not support sustained rotation and thus no tornado warnings or reports were issued/received. There were however multiple reports of hail, up to golf ball sized in some locations of eastern Iowa and even a 3″ report near Dubuque, along with some wind damage.

Stronger thunderstorms were present across eastern Kansas and western Missouri where thunderstorms initially developed behind the surface cold front and behind the dryline near Manhattan, KS. Additional thunderstorms formed along the front in northern Missouri, and finally along the front across the remainder of eastern Kansas shortly thereafter. However, thunderstorms persisted through the evening with reports of large hail, some as large as tennis balls, and some significant wind gusts near 80 mph with a few of the initial storms near Topeka, KS. Storms continued to be relatively high-based due to near 30 degree dew point depressions, thus despite some indications of rotation storms were hard-pressed to become tornadic. One storm in western Missouri did eventually show signs of tornadic activity with persistent, but weak low level rotation. This storm was the initial storm that formed near Manhattan, trekked east into slightly better low level shear and was able to garner a couple funnel cloud reports along with damaging winds.

The biggest report of the day likely came from near Williamstown, KS (just northwest of Lawrence) where a large, persistent gustnado formed in association with the storms’ RFD and the frontal boundary. There are several videos of this feature which show the broad rotation along the ground which picked up dust/dirt to make it visible. You can also tell in the video that cloud bases are rather high and according to reports there was never any discernible rotation within the clouds above. A NWS employee from Topeka had this statement on the feature:

well formed gustnado developed along the frontal boundary and rear flank boundary intersection…near williamstown on hwy24. winds inside the feature were sustained around 80 mph. the strong circulation persisted for nearly 5 minutes…with a max width of 0.25 mile. damage was limited to broken tree limbs.

I was able to witness some small hail a storm came rolling through Shawnee, KS during the late evening, however the bulk of the storm went just to the south and dropped quarter to golf ball sized hail across areas of Olathe, KS and Overland Park, KS. As this storm continued eastward into Jackson County, Missouri it continued to drop large hail to the size of tennis balls near Lees Summit, MO.

You can view all of these reports on the IEM LSR App.

Not a bad start to the beginning of the 2011 severe weather season, one that appears to be ramping up fairly quickly…

A large trough will dig into the Southwestern US late this week and kick out into the Central Plains on Sunday, creating the potential for a multi-day severe weather event across parts of the Central and Southern Plains. Both the GFS and ECMWF have a persistent dryline located across eastern Kansas and into central Oklahoma/Texas beginning on Thursday and continuing through Saturday, with slight disagreement on its’ location for Sunday. Strong moisture return should lead to dew points into the 60s within the warm sector and with temperatures likely in the 80s we should see ample instability once again. Obviously the details are sketchy at this point, but the pattern does indicate and support the potential for at least one significant severe weather day (likely Sunday) along with at least one or two additional marginal severe weather days for late this week and weekend.

Severe Weather Potential – April 3

// April 3rd, 2011 // No Comments » // Severe Weather, Severe Weather Forecast

A potent looking setup is taking shape for this evening and early overnight across the Central Plains with a moderate risk of severe weather currently issued by the SPC. A strong elevated mixed layer has moved over much of the risk area this morning, essentially capping any potential for showers or thunderstorms over the risk area. A strong southwesterly low level jet overnight has continued to push in very warm and moist air over the region with high temperatures likely well into the 70s and 80s across the risk area which extends from eastern Kansas across Missouri and into southeast Iowa and western Illinois. The potential for a few tornadoes, very large hail and damaging wind gusts will be present across this risk area during the evening and early overnight hours.

As a strong southwesterly low level jet continues through the afternoon it will continue to push stronger moisture into the area, with dew points likely near 60 to the mid 60s across the risk area. The ever-increasing deeper moisture is likely to yield mixed layer CAPE values of at least 1000 J/kg over the entire risk area, with even higher amounts near 2000 J/kg over far western Missouri and eastern Kansas just east of a dryline and south of the approaching cold front. As this cold front continues to push southeast this evening, strong cold air advection will eventually weaken the capping inversion across the risk area and lead to rapid and strong convection.

While wind profiles over much of the area will be fairly unidirectional, large speed shear will given way to at least 40-50 knots of deep layer sheer which will be supportive of supercells as initial storm mode. Closer to a surface low that will be focused near Illinois will be more southerly surface flow, leading to higher directional shear and likely supportive of at least a few tornadoes over mainly northeast Missouri, western Illinois and perhaps far southeast Iowa. Otherwise, abundant instability over eastern Kansas and far western Missouri just ahead of the cold front will likely give way to the potential for very large hail, this threat is nearly centered across Kansas City with initiation expected to occur over/near the Metro this evening. As storms continue into the evening they should begin to evolve into line segments and perhaps some bow echoes capable of damaging winds and some large hail…

The first significant severe weather day for the Central Plains is upon us…

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.