Two Brutal Large Storms Are Coming...

Añadido: 2026-05-28

[00:00:00]17 days. That is how long the southern United States has been under continuous heavy rain and flash flooding threats.

[00:00:06]17 days of a stalled frontal boundary parked across the lower Mississippi Valley and southern Mid-Atlantic. 17 days of upper level disturbances riding that boundary and triggering storm after storm after storm over the same geography. 17 days of soil that cannot absorb another drop being asked to absorb more. And as of 2:57 a.m. Eastern this morning, the WPC's short-range forecast discussion opened with this.

[00:00:30]Heavy rain and thunderstorms continue across much of the southern US through midweek, raising flash flooding and severe weather concerns. Turning more active across the west as a large Pacific low brings increasing rain and thunderstorm chances. Two separate storm systems, one already grinding through the south. One loading up in the Pacific and about to make its move east. Both of them are coming for the same country inside the same week. It is Wednesday, May 27th, 2026, day 147 of the year.

[00:00:56]Let's get into exactly what these two storms are, what they are each capable of, and what the combination of them means for tens of millions of people.

[00:01:04]Let me start with what is already happening because it is serious and it is active right now as you watch this.

[00:01:10]The WPC's short-range forecast discussion issued at 2:57 a.m. Eastern this morning describes the driving mechanism with clinical precision. A series of upper level disturbances interacting with a stalled frontal boundary stretching from the lower Mississippi Valley to the southern mid-Atlantic will lead to widespread showers and thunderstorms across much of the southern US. The next few days along and south of the boundary, a very warm, humid, and unstable air mass is and will remain in place, setting the stage for heavy rain and possible flash flooding through midweek. A stalled frontal boundary. That phrase is the key to understanding why the system has been so persistently damaging. A stalled front does not move through. It sits. And every upper level disturbance that rides along it. The WPC is explicitly flagging multiple pieces of energy within a southern stream shortwave passing through the south central US acts like a trigger that fires new convection over the same geography that just got hit by the last round. The technical term for what happens to rainfall totals in this scenario is training convection. Storms develop, fire track northeast along the boundary, and then the next batch develops in the same location and does the same thing. It is the meteorological equivalent of repeatedly pouring water into the same bucket, except the bucket has been overflowing for 2 weeks. The watchers documented as recently as May 25th that flood watches remained in effect across parts of the southern United States with clusters of storms capable of producing torrential rainfall leading to scattered flash flooding, particularly in urban areas and locations with poor drainage. They quoted the WPC directly. The series of upper level disturbances interacting with the stalled frontal boundary will continue supporting widespread showers and thunderstorms over much of the region during the next several days with a very warm, humid, and unstable air mass expected to maintain favorable conditions for heavy rainfall through at least midweek. At least midweek. Today is Wednesday. We are at midweek. And the WPC's extended forecast discussion from early Tuesday morning, valid from Thursday through Monday, June 1st, confirmed that heavy rain and thunderstorms are expected to continue across much of the southern US into the early days of June. That is an uninterrupted heavy rain and flash flooding threat stretching from midmay into the first days of June. Nearly 3 weeks of continuous soaking for the same communities. Now, let me tell you where the threat is most concentrated today and tomorrow. The WPC's excessive rainfall discussion from Monday evening flagged a long-ived convectively induced vorticity maximum of vort max sitting over the central part of Texas. A vort max is a spinning pocket of enhanced cyclonic vorticity embedded in the mid-level flow. When one of these sits over location for an extended period, it acts like an atmospheric anchor, organizing convection repeatedly over the same spot, enhancing lift locally beyond what the broad pattern alone would produce and driving rainfall rates that can reach 2 to 4 in per hour in the cores of the most intense cells of T-Max sitting over central Texas on top of an already saturated landscape with Pwatt anomalies that the WPC documented at plus one to plus two, five standard deviations above normal is a recipe for locally catastrophic flash flood.

[00:04:09]And the SPC's day one outlook this morning is not quiet either.

[00:04:12]Thunderstorms with large hail, severe wind gusts, and a couple of tornadoes are expected this afternoon and evening across parts of West and Southwest Texas. Isolated severe gusts and a marginal tornado threat will be possible in parts of Kentucky. Isolated severe gusts and hail may also occur in parts of the upper Midwest and Northern Rockies. West and Southwest Texas for severe storms today. Kentucky for isolated severe gusts and marginal tornado potential. The upper Midwest and Northern Rockies for isolated hail and wind. This is not a single corridor event. It is multi-reional, multi-hazard, active right now and running on top of a landscape that has been absorbing punishment for 17 consecutive days. Here is what I need everyone in the Texas Hill Country to hear clearly because this region deserves to be named specifically and unambiguously every single time heavy rain is in the forecast anywhere near it. the Vortmax sitting over central Texas today, the pew watt anomalies exceeding plus two standard deviations above normal, and the saturated soil conditions across the Edwards Plateau and surrounding wersheds are a combination that the July 25 Kerr County disaster demonstrated can produce 20 foot river surges in a matter of hours.

[00:05:21]You do not need a widespread organized storm system to flood the Guadalupe, the Yano or the Panales. You need one intense cell sitting in the wrong location for the wrong duration over terrain that funnels every drop of water downhill at speed. That is today's setup in central Texas. Watch the river gauges. Watch the radar. Know your roads. Before I get to storm two, I need to flag something the WPC specifically called out in both its Monday and Tuesday morning short range discussions that is getting almost no attention and deserves some. The WPC's short-range forecast discussion, issued 2:57 a.m.

[00:05:53]Tuesday, flagged this directly.

[00:05:55]Unseasonably hot weather continues across the northern plains and upper Midwest the next few days as temperatures soar 20 to 30 degrees above normal. 20 to 30 degrees above normal in the northern plains and upper Midwest while the South drowns and storm 2 loads up in the Pacific. The atmospheric split that has been running all spring, the same split flow pattern that has been fueling this entire season is currently producing its most extreme simultaneous contrast of the year. Communities in North Dakota, South Dakota, Minnesota, and Wisconsin are hitting highs in the 90s. Some locations may approach records for late May. The same jetream configuration that is stalling the frontal boundary across the south is pumping a ridge of warmth northward into the northern tier at the same time. Why does this matter for a storm discussion?

[00:06:40]Because that 20 to 30° anomaly north of the frontal boundary means that when storm 2 arrives and the front finally moves, it is not going to collide with a neutral air mass. It is going to collide with an air mass that has been preheated for days. The temperature gradient across the frontal boundary, the difference between the hot air to the north and the storm systems cold air to the west, is the energy source for frontal precipitation. The larger the gradient, the more violent the frontal response. A front colliding with air that is 20 to 30° above normal produces more intense storms along its leading edge than a front hitting air that is 5 degrees above normal. And the northern plains air mass right now is 20 to 30 degrees above normal. That is the fuel source that storm 2 is going to tap when it arrives. Here is where the second act of this two storm sequence begins. And unlike storm one, which is a stalled, diffuse, moisture persistence event, storm 2 is a discrete, organized mobile system with specific and dangerous characteristics that I want to walk through carefully. The WPC's short-range forecast discussion from 2:57 a.m.

[00:07:41]Tuesday described it in its headline, bullet, turning more active across the West as a large Pacific low brings increasing rain and thunderstorm chances along with some high elevation snow. A large Pacific low, that is how the WPC is describing it. Not a short wave, not a subtle disturbance, a large Pacific low. These systems develop over the open Pacific, spend days winding up over the ocean, where there is no friction to slow them down, and arrive at the West Coast already organized and energetic.

[00:08:07]The WPC's extended forecast discussion valid [clears throat] from Friday, May 29th through Monday, June 1st, confirmed that a closed upper low will be located over the central Great Basin when the extended period begins Friday and should lift northeastward and weaken by the weekend as another short wave slides through the Pacific Northwest later in the period. a closed upper low over the great basin by Friday. Let me translate that. When an upper trough wraps up and closes off, when the geopotential height contours form a complete closed circle around the low, it is a sign of a deep, cold, wellorganized system. Closed lows are more persistent than open troughs because they do not move with a mean flow as efficiently. They can stall, dig, and maintain their organization for longer than open wave systems. And when they eject eastward, when the atmospheric dynamics finally push them off the Great Basin and into the Rockies and Plains, they can produce explosive cyclloenesis at the surface, dramatic wind shear enhancement, and rapid severe weather development. The SPC's day 4 through 8. Convective outlook issued 3:38 a.m. CDD, Tuesday, May 26th, documented the trajectory of the system in detail. An upper low is forecast to be located over the Great Basin on Friday, moving into the northern Rockies and high plains through Saturday and weakening all the while. Models indicate 500 mibs by Saturday, will only be in the 20 to 25 knot range with this feature. Therefore, despite low 60s due points, the severe risk is expected to be somewhat disorganized. Somewhat disorganized does not mean non-threatening. It means the forcing is not sharp enough to produce a classic well-defined severe weather corridor with confident model agreement. What it produces instead, and this is actually in some ways more dangerous from a forecasting standpoint, is a sprawling disorganized severe weather potential spread across a large geographic area where individual cells can fire with limited warning in locations that are not under the most prominent risk areas.

[00:10:00]But here is the piece that the SPC's day 4 through 8 discussion also flagged and that matters enormously for the overall threat picture. A low latitude shortwave trough is forecast to move across the southern plains and into the lower Mississippi Valley from Saturday into Sunday given the expected very moist air mass in place with 70°ree due points and lack of capping. Scattered areas of thunderstorms are likely throughout the period. Much of the activity will occur over Texas and Oklahoma where moderate instability is forecast. 70°ree due points, no capping, scattered thunderstorms likely throughout the period. Over Texas and Oklahoma, 70deree due points are not a marginal number.

[00:10:35]They are tropical. They are the kind of surface moisture that produces cape values in the thousands with minimal forcing. When you have 70°ree due points, no convective inhibition, a moderate instability already in place, and a short wave moving through, you do not need a high-risisk environment to produce damaging locally violent storms.

[00:10:53]You need one cell to find the right wind shear profile and you have a significant tornado producing supercell. The Climate Prediction C Center's probabilistic hazards outlook valid through Sunday, May 31st and into early June confirmed that the GEFS and EENS models are in good agreement that a 500 HPA trough amplifies along the east coast later next week, leading to a cold front shifting into the southeast by the end of May. That front is forecast to become stationary, the same mechanism that has been driving Storm 1. And with the truffle loft, the pattern is favorable for enhanced precipitation across the southeast to start June. A slight risk of heavy precipitation has been posted for parts of the southeast from June 1st through June 4th. So storm 2 does not just arrive and depart cleanly. It sets up the next stall. It becomes the next version of storm 1. The front becomes stationary. The moisture stays anomalous. The upper level energy keeps riding the boundary. and the region that has been absorbing 17 consecutive days of heavy rain and flash flooding threats gets handed off into another chapter of the same story with a new storm engine driving it. I want to explain something about compound flooding that I think most weather coverage does not adequately convey because it is the specific reason why the phrase two brutal large storms in this title is not hyperbole. When a single major storm system produces 3 in of rain over a watershed in a week, the wershed absorbs it imperfectly, has some flooding in the low-lying areas, the rivers run high, and then they gradually recede over the following days as the ground slowly releases moisture back into the drainage network. That is a manageable event, damaging in places, dangerous in spots, but recoverable. When a second storm system produces another 3 in of rain over the same watershed before the first event has drained, before the rivers have receded, before the soil has released its moisture, before the drainage infrastructure has recovered its capacity, the hydraological response is not additive. The drainage network is already at or near capacity, the soil has zero absorption remaining. The rivers are already running elevated.

[00:12:49]Every drop of the second event's rainfall goes directly into surface runoff with no buffering. Rivers that were at minor flood stage from the first event surge into moderate or major flood stage from the second. Culverts that were managing the first events runoff fail under the second events load. Urban drainage that had partially recovered overflows again, but this time faster and deeper. The WPC's extended forecast discussion from Tuesday morning flagged this specifically. Heavy rain is possible. And given how wet a lot of this region has been lately and will be in the short range as well, flooding could be a concern in some places. could be a concern is the WPC's understated way of saying this is a serious problem.

[00:13:28]They are not issuing that language casually. They're issuing it because the model guidance is showing continued heavy rain over a region that their own data shows has been wet for weeks and they know what that means for flash flooding outcomes. For the Texas Hill Country, specifically the Guadalupe River Basin, the Panalis wershed, the Yano River corridor, this compound flooding mechanism is not hypothetical.

[00:13:49]It is documented. The July 2025 disaster in Kirk County happened when a moisture-laden system moved over terrain that was already wet from prior events.

[00:13:58]The river response in that event was measured in minutes, not hours. People who were monitoring the situation were caught off guard, not by the rain, but by the speed of the surge. The rain gauge at their location showed 2 in. The river rose 20 ft because it was draining a watershed that had absorbed 6 in of rain 30 m upstream. The compound flooding mechanism kills people in the Texas Hill Country because the water that arrives at your location did not fall at your location. It fell miles away and gravity collected it all and sent it downstream in one concentrated pulse. That mechanism is active right now. Storm one has preloaded the wershed. Storm 2 is coming to pull the trigger. Let me be specific about who is looking at which threat and in what window because the two storm structure means different regions peak at different times. Central and South Texas, including the Hill Country, today through Friday. This is your most dangerous window. The Vortmax sitting over central Texas today, the long live convective activity, the P watt anomalies exceeding plus two standard deviations, and the zero remaining soil absorption capacity in the Hill Country wersheds are all converging right now.

[00:15:01]The SPC has severe storm potential across West and Southwest Texas today with large hail and a couple of tornadoes possible. The flash flooding threat is the co-equal or greater concern. Watch the USGS stream gauges.

[00:15:13]Watch the radar. Know your roads and know which ones flood first, the lower Mississippi Valley and southern Appalachians today through the weekend.

[00:15:20]The stalled frontal boundary with its continuous series of upper level disturbances is going to keep targeting this corridor through at least midweek for the WPC's short-range discussion and into the weekend and early June for the extended discussion. Flash flooding in urban areas, along small streams, and in lowlying areas is the primary threat.

[00:15:39]Flood watches have been active across parts of this region for days and are going to remain active. The southeast specifically Georgia, the Carolas, Tennessee, Alabama comes into increasing focus as the trough amplifies along the east coast by the end of next week.

[00:15:53]Oklahoma, Kansas, and the southern plains Saturday through Sunday. The low latitude short wave that the SPC's day 4 through 8 discussion flagged will move across the southern plains on Saturday and into the lower Mississippi Valley on Sunday. With 70°ree due points and no capping across Texas and Oklahoma, scattered thunderstorm development is likely throughout this period. Moderate instability means individual storms can produce hail and wind without reaching the headline severe weather parameters.

[00:16:20]But in a 70°ree dupoint environment with no cap, initiation is easy and upscale growth into organized storm clusters is possible. Watch the SPC's day two and day one outlooks Friday and Saturday morning for any upgrade in the risk level for Oklahoma and southern Kansas.

[00:16:34]The Pacific Coast and Rockies Thursday through the weekend. The large Pacific low is bringing increasing rain and thunderstorm chances to the west as it approaches with some high elevation snow in the Cascades and Northern Rockies. By Friday, the closed upper low is forecast to be positioned over the Great Basin.

[00:16:50]By Saturday, it is moving into the northern Rockies and high plains. For the northern plains communities that have been experiencing 20 to 30 degree above normal temperatures, that warmth ends as the system arrives. The temperature crash on the backside of the system is going to be significant. And for agricultural regions in the northern plains that have been in the warm pocket, watch the overnight lows through the weekend as the upper low brings the first real cold air intrusion in nearly a week. the northern plains and upper Midwest this weekend into next week. As the upper low moves through the northern Rockies and weakens over the high plains, its cold air spreads east. The WPC's extended discussion notes that after the anomalous warmth of this week, temperatures trend toward more normal levels as the system arrives. For communities in Minnesota, Wisconsin, and Michigan that have taken repeated frost and freeze events this spring, the temperature trajectory through the weekend back toward more seasonal normals warrants watching, particularly for overnight lows following what is going to be a dramatically warm late May week. Here is what you need to do by region starting today. Texas Hill Country, Kurville, Fredericksburg, Junction, Yano, Marble Falls, and surrounding communities. Pull up the USGS National Water Information System for the Guadalupe River at Comfort and at New Bronfells, the Yano River at Junction, and the Pternal River at Johnson City. Bookmark those pages.

[00:18:05]Check the morning and evening through Saturday. Know what the stage was before storm one arrived. Know what normal bank looks like for your specific river. And if you see the gauge moving up more than 2 feet in a 30inut window, that is a rapid rise event, and it means the upstream rainfall pulse is on its way.

[00:18:20]Get out of any low-lying areas immediately and do not wait to see how high it gets. Southern Plains and Gulf Coast, Texas, Oklahoma, Louisiana, Mississippi, Alabama. You're in the active zone for both storm systems this week. Keep your weather alerts on your phone confirmed and active. If you receive a flash flood warning for your county, not a watch, a warning. That means flooding is imminent or already occurring, leave any low-lying area immediately. Do not drive through water on any road. Do not estimate depth by looking. Do not assume it is passable because other vehicles went through. 6 in of fastmoving water can knock a person down. Two feet of moving water can sweep a vehicle off the road. Every year people die in this situation because they judged it with their eyes instead of turning around. The southeast, Georgia, the Carolinas, Tennessee, Kentucky. The flash flooding threat here is lower than the Gulf Coast, but it is persistent and it is going to intensify as the trough amplifies along the east coast by the end of next week. The CPC's probabilistic hazards outlook has already posted a slight risk of heavy precipitation for the southeast from June 1st through 4. Urban areas and locations near small streams are the most vulnerable. Know your local NWS office and check their forecast discussion every morning this week. The northern Rockies and high plains, Montana, Idaho, Wyoming, Eastern Colorado. High elevation snow is possible in the Cascades and Northern Rockies through the weekend as the Pacific low moves through. For anyone traveling mountain passes this weekend, check road conditions before you leave.

[00:19:47]The elevation where snow transitions to rain can shift rapidly with a closed upper low moving through and past conditions can deteriorate faster than forecast. Everyone, the WPC's headline for the next 48 hours is heavy rain and thunderstorms continuing across much of the southern US through midweek, raising flash flooding and severe weather concerns and turning more active across the West as a large Pacific low arrives.

[00:20:10]That is not a regional advisory that covers the eastern twothirds of the country for the first storm and the western third for the second. There is essentially no quiet corner of the continental United States this week.

[00:20:22]Stay weather aare. Check your local forecast every morning. Two storms, both confirmed and documented in official forecast discussions issued in the last 24 hours. Storm one, a stalled frontal boundary from the lower Mississippi Valley to the southern mid-Atlantic that has been producing heavy rain and flash flooding threats for 17 consecutive days driven by a series of upper level disturbances and a very warm, humid, and unstable air mass that the WPC says will remain in place through at least midweek. And the extended discussion says continues into early June. Storm two, a large Pacific closed upper low moving over the Great Basin Friday into the northern Rockies and high plains Saturday, followed by a low latitude shortwave crossing the southern plains on Saturday and Sunday with 70° due points, no capping, and moderate instability producing scattered thunderstorms across Texas and Oklahoma throughout the period. The compound flooding mechanism means storm 2 lands on a landscape that storm one has been saturating for nearly three weeks. The soil has no capacity. The rivers are running high. The drainage infrastructure is stressed. Every inch of rainfall from storm 2 produces flooding outcomes that are disproportionate to what the storm alone would cause in a fresh environment. And the northern plains air mass running 20 to 30° above normal right now is the fuel source that will make the frontal collision when storm 2 arrives more energetic and more volatile than the atmospheric parameters of the storm alone would suggest. This week is brutal. Both storms are real. Both are documented in official WPC and SPC language from the last 24 hours. And the combination of them targeting the same geography in sequence is the specific mechanism that turns a difficult weather week into something significantly more dangerous. Stay with Planet Brief.