u/Curious_Passion5167

...SUNDAY/Day 3

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...

Severe storms will be likely Sunday from portions of the central and southern High Plains into the Upper Midwest. Supercells capable of all hazards will be possible before upscale growth and an emerging damaging wind risk continues into the evening.

...Synopsis...

An upper-level trough will begin to eject across the Intermountain West on D3/Sunday with a more subtle shortwave trough moving across the central Plains. As a result, deepening low pressure will develop across eastern Colorado/western Kansas with strengthening southerly flow and warm moist advection south of a warm front lifting northward into the northern Plains and upper Midwest. Early in the period, elevated storms will likely be ongoing across portions of Iowa into southern Minnesota. Scattered severe storms capable of all hazards will be expected to develop near the warm front/low across eastern Colorado into Nebraska and across southern South Dakota continuing into portions of the upper-Midwest along the cold front through the evening. A more isolated and conditional threat for severe storms will extend southward along the dryline from western Kansas into western Oklahoma.

...Central Plains into the Upper Midwest...

Early day elevated convection is expected to move across portions of Iowa into the upper-Midwest. This will pose some risk for severe hail through the morning. Across the central Plains, strong daytime heating is expected to yield moderate to strong instability across much of the central Plains. This in combination with strong deep layer shear suggests a rather volatile environment, particularly across central Nebraska into southern South Dakota/northwestern Iowa. Guidance suggests that thunderstorms will develop across eastern Colorado into Nebraska by the afternoon. Initial thunderstorm development will likely be supercellular and capable of all hazards including large to very large hail, damaging wind, and tornadoes. As the front sags southward through the evening, eventual upscale growth into a squall line is expected by the evening. A strong 50 kt low-level jet will ramp up into the evening, which may support a continuing potential for tornadoes, some of which may be strong.

...Western Kansas into western Oklahoma...

A more conditional threat may extend southward along the dryline into western Kansas and western Oklahoma. Guidance suggests some signal for isolated supercells to develop along and east of the dryline Sunday afternoon. The environment here will conditionally favor large to very large hail, damaging wind, and perhaps a tornado or two with the strengthening low-level jet in the evening.

...MONDAY/Day 4...

A severe weather outbreak will be possible from Monday afternoon into the evening and overnight period. On Monday, the western trough will take on a negative tilt before ejecting across the central Plains, with strong southwesterly flow aloft overspreading the region. This will result in strong lee cyclone development across western Kansas. A surface cold front will extend northward to a secondary surface low across the upper Midwest. A dryline will extend southward across portions of western Kansas into western Oklahoma. Numerous thunderstorms are expected to develop along and ahead of the cold front and further south along the dryline Monday afternoon and evening from Nebraska into central Kansas. Given the volatile air mass ahead of these features, with moderate to strong instability and strengthening deep layer shear, initial development will likely be supercellular. Initial supercells will pose risk of all hazards including large to very large hail, damaging wind, and tornadoes. As the southwesterly low-level jet increases into the evening, large clockwise enhancement of low-level hodographs across portions of central Kansas into northern Oklahoma may lead to an increasing risk for strong to intense tornadoes. Additional thunderstorm development will spread in tandem with the cold front from the central Plains to the upper Midwest through the evening, with potential for more widespread damaging wind and a few tornadoes (some of which may be strong).

...TUESDAY/Day 5...

Severe potential is expected to continue D5/Tuesday as the cold front extends from the upper Midwest to southern Plains. Strong to moderate instability ahead of the front will continue to support severe storms from the northern part of the southern Plains northeastward into the mid Mississippi Valley. Trends are for the front to shift eastward faster than originally expected, and as such probabilities were shifted eastward with this update. Strong to severe storms may extend further north into the northeast and Great Lakes Region.

Day 4-8 Convective Outlook

NWS Storm Prediction Center Norman OK

0401 AM CDT Thu May 14 2026

Valid 171200Z - 221200Z

...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/SUN...D5/MON...

...DISCUSSION...

...Sunday/Day 4 and Monday/Day 5...

An upper-level trough is forecast to move eastward across the Intermountain West on Sunday, as a subtle shortwave trough moves northeastward across the Great Plains. Ahead of the trough a moist and unstable airmass is forecast across much of the Great Plains eastward into the Mississippi Valley. Scattered elevated strong thunderstorms will be possible early in the day from the northern Plains eastward into the upper Mississippi Valley. Southward into the central Plains and mid Missouri Valley, strong surface heating is forecast. Some models suggest MLCAPE could peak in the 3000 to 4000 J/kg range. In addition, a broad 40 to 50 knot low-level jet is forecast to strengthen late Sunday afternoon. This, combined with moderate to strong deep-layer shear over much of the moist sector will be favorable for severe storms potentially over a large area. A severe weather outbreak will be possible from the afternoon and evening into the early overnight period. The setup appears favorable for supercells with tornadoes, large to very large hail and wind damage.

On Monday, model forecasts eject a negatively-tilted upper-level trough into the central Plains. Ahead of the trough, a moist and unstable airmass is forecast to be located from the southern and central Plains northeastward into the Upper Midwest. A mid-level jet is forecast to also eject northeastward across the central Plains as a broad low-level jet strengthens during the late afternoon. Thunderstorm development is expected along the western edge of the airmass near a dryline over west-central Kansas and southeast Nebraska. Thunderstorms that move into the strong low-level flow in the late afternoon and early evening will have potential to be supercells with large to very large hail, and tornadoes. Severe wind gusts will also be possible. A severe weather outbreak will be possible from Monday afternoon into evening and overnight period.

...Tuesday/Day 6 to Thursday/Day 8...

On Tuesday, mid-level southwesterly flow is forecast over the central U.S., with a cold front moving southeastward through the central Plains and Upper Midwest. Ahead of this front, surface dewpoints from the mid 60s to the lower 70s F are expected to contribute to moderate to strong instability. Thunderstorm development with a severe threat will be possible along and ahead of the front during the afternoon and evening from the northern part of the southern Plains northeastward into the mid Mississippi Valley.

On Wednesday and Thursday, the cold front is forecast to move slowly southeastward across the southern Plains and mid Mississippi Valley, extending east-northeastward into the Mid-Atlantic. A severe threat could develop along and ahead of the front each afternoon and evening. However, uncertainty concerning the exact location of the front is substantial at this extended range.

..Broyles.. 05/14/2026

Day 4-8 Convective Outlook

NWS Storm Prediction Center Norman OK

0357 AM CDT Wed May 13 2026

Valid 161200Z - 211200Z

...DISCUSSION...

...Saturday/Day 4 to Monday/Day 6...

At mid-levels, a shortware trough will move eastward across the western U.S. on Saturday, as flow becomes west-southwesterly over much of the central U.S. In response, moisture advection is forecast to increase over the central U.S. as a pocket of 65 to 70 F dewpoints moves northward into the lower and mid Missouri Valley. A dryline is forecast on the western edge of the moist airmass. Isolated to scattered storms appear likely to initiate to the east of the dryline in the afternoon. Additional storms may form eastward across the lower to mid Missouri Valley. Moderate deep-layer shear is forecast over the instability axis, which should support a potential for supercells with large hail and severe wind gusts.

On Sunday, an upper-level trough is forecast to develop over the western U.S. Mid-level flow is expected to become southwesterly over the Great Plains, where model forecasts show a surge of low-level moisture. In response, surface dewpoints are forecast to increase into the mid to upper 60s F over much of the north-central U.S. A series of subtle shortwave troughs moving through the Great Plains will likely support scattered to numerous thunderstorms in the afternoon and evening. The greatest severe threat may develop over eastern Nebraska and western Iowa, along the northern edge of a low-level jet. A potential for supercells with large hail, wind damage and a tornado threat is expected.

On Monday, the upper-level trough is forecast to move across the Intermountain West, as multiple shortwave impulses move northeastward across the Great Plains. A cold front is forecast to move southeastward across the central U.S. Ahead of the front, surface dewpoints in the lower to mid 70s F are forecast to be in place by afternoon. In response, strong instability is expected to develop in parts of the moist airmass. In addition, a mid-level jet is forecast to eject northeastward across the central U.S. Moderate to strong deep-layer shear associated with the jet will support a potential for severe storms across a broad area from the southern Plains northeastward into the Upper Midwest. Supercells and bowing line segments with large hail, severe wind gusts and tornadoes will be possible.

...Tuesday/Day 7 and Wednesday/Day 8...

On Tuesday and Wednesday, a cold front is forecast to move from the Upper Midwest southeastward into the Appalachians. A moist and unstable airmass will likely be in place ahead of the front, with scattered to numerous thunderstorms likely developing each afternoon and evening. The greatest severe threat could materialize over the mid Mississippi and lower Ohio Valley on Tuesday, and in the Northeast on Wednesday, adjacent to a mid-level jet passing through. However, uncertainty is substantial at this time concerning the timing of the upper-level trough and cold front.

..Broyles.. 05/13/2026

Day 4-8 Convective Outlook

NWS Storm Prediction Center Norman OK

0357 AM CDT Tue May 12 2026

Valid 151200Z - 201200Z

...DISCUSSION...

...Friday/Day 4 to Sunday/Day 6...

Over the weekend, mid-level flow is forecast to gradually become southwesterly across the central U.S. In response, low-level moisture advection will occur in the Great Plains. By Friday afternoon, a moist and unstable airmass is forecast to be in place from north Texas into Oklahoma, eastern Kansas and central to northern Missouri. Isolated severe storms will be possible within this airmass Friday afternoon and evening.

On Saturday, a dryline is forecast to develop from the far eastern Texas Panhandle northward into west-central Kansas. To the east of the dryline, surface dewpoints in the 60s F will contribute to moderate instability by afternoon. As a mid-level shortwave trough approaches in the afternoon, scattered thunderstorms are expected to form to the east of the dryline from western Oklahoma into central and eastern Kansas. Supercells with large hail, severe wind gusts, and a tornado threat could develop.

A surge of deeper low-level moisture is expected across the southern and central Plains on Sunday, as an upper-level trough moves through the western U.S. In response, a north-to-south corridor of strong instability is forecast by afternoon from western Oklahoma north and northeastward into central and eastern Kansas. Scattered thunderstorms are expected within this unstable airmass during the afternoon and evening. MCS development may occur in the evening as a complex moves northeastward from the central Plains into the mid Missouri Valley. Supercells with large hail, severe wind gusts and a tornado threat will be possible.

...Monday/Day 7 and Tuesday/Day 8...

An upper-level trough is forecast to move across the north-central U.S. on Monday, as a cold front advances southeastward into the mid Mississippi Valley, Ozarks and southern Plains. Scattered to numerous thunderstorms are forecast to form ahead of the front in the afternoon. At this time, model forecasts suggest that instability and deep-layer shear will be strong enough for severe storms across a broad area. However, uncertainty exists concerning the location of the front Monday afternoon. A severe threat area may be needed in later Outlooks, once confidence increases concerning the timing of the front.

On Tuesday, the cold front is forecast to move southward into north Texas and the southern Ozarks. An isolated severe threat could develop ahead of the front in the afternoon and evening. However, uncertainty is substantial at this extended range.

..Broyles.. 05/12/2026

Nobody's posted it yet?

...Saturday/Day 6...

By Saturday, a wide corridor of moderate instability is forecast to be in place over the Great Plains. A shortwave trough is forecast to move into the central U.S. during the afternoon. Ahead of the shortwave, scattered thunderstorms will be possible from north Texas northward into Nebraska. Along the western edge of the instability corridor, steep mid-level lapse rates and moderate deep-layer shear are forecast. The environment could support large hail, damaging wind gusts, and an isolated tornado threat in the southern and central Plains, where instability, shear, and lift are forecast to become maximized.

...Sunday/Day 7 and Monday/Day 8...

On Sunday, mid-level flow is forecast to be southwesterly over the central U.S., as a shortwave trough moves into the Great Lakes. Another shortwave trough is forecast to move into the northern High Plains. Further south in the southern and central Plains, moderate to strong instability is forecast to be in place by midday. Thunderstorm development is expected over parts of this unstable airmass in the afternoon and evening.

Although uncertainty exists concerning the location of the greatest severe threat, some solutions suggest potential for a large complex of storms from eastern Kansas into Missouri. At this time, too much uncertainty exists for the addition of a severe threat area.

On Monday, a front is forecast to advance southeastward across the central U.S. Ahead of this front, isolated severe storms will be possible near an axis of instability in the afternoon and evening. However, model spread is relatively large concerning the timing of features at this extended range.

- SPC (Broyles)