131 FOUS30 KWBC 150811 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 411 AM EDT Wed Jul 15 2026 Day 1 Valid 12Z Wed Jul 15 2026 - 12Z Thu Jul 16 2026 ...THERE IS A HIGH RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE EDWARDS PLATEAU, CENTRAL RIO GRANDE VALLEY, AND HILL COUNTRY... ...Texas... Current satellite and radar composite depict a defined low to mid- level circulation situated over the Edwards Plateau into the neighboring Hill Country along and north of US90 to the west of San Antonio. Heavy rainfall continues within the confines of the disturbance with rainfall rates generally between 2-3"/hr in the stronger cores nestled within the meandering complex. Recent CAMs have been struggling with the handling of this feature with the latest 00z suite running too quiet in terms of the current convective coverage and what was being forecast. This effect left some of the current probability fields on the conservative side compared to the past runs, but even still, the results are formidable. 850mb UA analysis indicates a ~25kt LLJ centered over the southern Hill Country with the nose of the jet protruding into the Edwards Plateau. Expectation for the maturation of the LLJ will be generally similar to last night where an expected redevelopment of convection will ensue over the Rio Grande Valley and points west, overlapping many of the areas that were recently impacted by considerable rainfall in the past 12-24 hrs. This stems from the LLJ influence and the overall convergence scheme being exacerbated by both the MCV and the positioning of a surface trough analyzed in the area. Despite the lower confidence in the full CAMs output, the QPF totals being disseminated in the hi-res are still incredibly concerning and the story is validated through the HREF neighborhood and EAS prob fields all the same. HREF blended mean QPF depicts widespread 3-6" of rainfall with locally up to 8" across the Edwards Plateau, RGV, and Hill Country to the southeast of I-10. This is also just the mean QPF depiction as a few deterministic members are amplifying further with 10+ inch forecasts showing up over portion of the Edwards Plateau and lower Concho Valley. One of the biggest trends has been the uptick in the signal across Crockett County and points southeast into Hill Country where model consensus shows the highest threat for significant rainfall totals >5". Neighborhood probabilities for the >5" threshold are running between 40-70% in this general area for the period with the >8" threshold solidly between 30-50% for the same region. Historical precedence for these types of probabilistic outputs points to a significant event with life- threatening characteristics increasingly favorable across the areas hardest hit. Couple the expected additional rainfall with widespread 6+ inch totals that already occurred in the region and you have a recipe for high level impacts and major hydrologic concerns through a broad area. The previous forecast High Risk remains valid and the risk inherited was maintained with some small adjustments around the northern periphery of the risk area, expanding more into the Lower Concho Valley across Crockett County. The eastern extent is still situated west of I-35 with the Hill Country to RGV the most prominent focus for significant, life-threatening flash flood prospects. MDT risk extends a bit further north towards San Angelo, but still remains south of the population center. This is a close setup for the area, so will be monitoring closely to see if the more appreciable rainfall can make it that far north to provide more locally significant impacts to the Central Concho Valley. Heavy rain threat will also exist out towards the Big Bend into the Lower Trans Pecos, especially the following evening, but that area is more fluid as the behavior of the MCV will be integral to the western extent of the heaviest rainfall. The High Risk location is where confidence is high on the three major characteristics for the setup: high intensity rates between 2-4"/hr, overlapping heavy rainfall over areas previously impacted, and consensus within the CAMs on where redevelopment is likely, validated by the HREF probability fields. This setup will need to be monitored very closely and for everyone to heed all watches and warnings due to the gravity of the setup. ...Central Arizona into the Interior West... So far models remain consistent on the broad upper ridge centered over the Northern U.S. continuing to provide significant moisture advection into the interior west leading to scattered convective signals from the Canadian border down into the Desert Southwest with flash flood concerns in those more susceptible areas out west. The signal for heaviest rainfall continues to be situated within the proximity of the terrain across Central AZ where CAMs depict a broad convective initiation after 19z centered within a defined theta_E ridge positioned from southeastern AZ up through the Mogollon Rim. 00z HREF neighborhood probabilities are generally robust for at least 1" of rainfall across the terrain between Phoenix to Flagstaff with probabilities between 60-80% showing up over the higher terrain located within the Mogollon Rim. Neighborhood 2" probs are relatively modest between 30-50% for the same area, a signal sufficient enough to maintain the previously inherited SLGT risk with only some minor adjustments on the southeast flank of the risk. Prevailing upper level flow is still likely to lead to precip moving southwest off the terrain and towards the adjacent valley in south-central AZ, so the prospects for flash flooding near Phoenix are higher than in recent periods, but still generally favored for a MRGL risk. Outside AZ, scattered thunderstorms are likely to materialize within the Great Basin up into the ranges of northwest WY into southern MT due to a continued elevated deep layer moisture advection regime bisecting the area for another few periods. The main concern will be flash flood threats in any urban settings and those more susceptible slot canyons across UT and northern AZ north of I-40. A broad MRGL risk extends north through the above areas with isolated to widely scattered flash flood prospects expected for these domains. ...Lower Mississippi Valley into Southeast... Our meandering upper level disturbance continues to churn over the Southeastern U.S. with the center of circulation analyzed over northern MS according to UA analysis and a defined cyclonic character via the latest WV satellite imagery. Expectations are for this slow-moving disturbance to drift to the west-northwest with sights on the Lower Mississippi Valley by later this afternoon as the HREF 700-500mb analysis pins the circulation crossing into southwestern AR later this morning, drifting towards the center of the state by the middle of the afternoon. Elevated moisture and general diurnal destabilization across the Lower Mississippi and Southeastern U.S. will lead to another round of slow-moving thunderstorms capable of producing locally heavy rainfall with rates of 2-3"/hr likely in those stronger cell cores. The setup is not as prolific within the QPF means compared to the previous few periods, and the area FFG's across AR are much higher compared to points further east where multiple days of rainfall compromised the top soil layer enough to warrant greater impacts with any convective episodes. Given the aforementioned variables, the threat remains within the MRGL risk threshold with little change from the inherited forecast. We will continue to monitor closely on any potential targeted upgrades over the region. Kleebauer Day 2 Valid 12Z Thu Jul 16 2026 - 12Z Fri Jul 17 2026 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE EDWARDS PLATEAU, CENTRAL RIO GRANDE VALLEY, AND HILL COUNTRY... ...Texas... Convection will continue across the Edwards Plateau and surrounds for at least one more period as the regional pattern maintains a persistence in its evolution with yet another round of convection lingering through the morning from the previous period, and one last round of nocturnal convection anticipated the evening of Thursday into early Friday morning. The past few iterations of the CAMs and global deterministic are coming into better alignment on how they have the event across TX playing out with a strengthening signal for heavy rainfall in-of the Central RGV up through the Concho Valley and slipping into the southeastern Permian Basin. Ensemble means have exhibited a crescendo in the depicted areal average QPF leading to generally robust totals bordering between 2-4", locally higher in the hardest hit locations. Considering the nature of anticipated compromised soils and ongoing flooding across portions of the RGV and Edwards Plateau, very little additional rainfall would cause a myriad of problems, including an exacerbation of any remnant flood waters, especially if impacted by additional heavy rainfall >1"/hr as noted via the very low FFG's already in place across the region. The previous MDT risk was maintained and even expanded a bit eastward through more of the Hill Country over into the Edwards Plateau with emphasis on Val Verde county extending up to the neighboring counties to the north, including the I-10 stretch in central Crockett county. This is the area of greatest concern for the setup in D2 leading to a high-end MDT risk forecast centered over this corridor. Rainfall totals in a narrow tongue could breach 6" locally as asserted by a few of the deterministic outputs which makes sense considering the incredibly moist environment in place. This period will be monitored very closely and its susceptible to larger scale changes as the setup evolves as the handling of the MCV and the placement of the quasi- stationary front and any surface trough axis' in the area will be foci for heavy convection. Heavy rain will enhance life- threatening flash flooding to portions of the region for yet another period before the setup finally looks to break heading into D3. ...Southwest U.S into the Great Basin... Another round of afternoon and evening convection will transpire across the Southwest CONUS into the Great Basin on Thursday with the threat carrying into the early morning periods of Friday in some locations. Models are keen on a more robust moisture advection pulse and general instability axis across the Desert Southwest on Thursday with a broad axis of heavy rain prospects from the southern border all the way north into southern UT. Hi-res ensemble and several global deterministic outputs remain very bullish on the threat in and around the slot canyons of southern UT, along the Mogollon Rim, and down towards the terrain embedded within Cochise, Santa Cruz, and Pima counties. Areal average of 1-2" is forecast for the region along the southern border with 1-1.5" forecast across the Mogollon Rim and southern UT. Considering the environment maturing closer to 1000-2000 J/kg MUCAPE over much of AZ into southern UT/NV, instability and anomalous moisture within the 90-99th percentile of climatology across the region will produce more widespread heavy rain prospects leading to scattered flash flood occurrences in those more susceptible locations in the terrain. There is even some opportunity for thunderstorm genesis off several outflows that could impact some of the larger urban corridors within AZ, including the Phoenix metro as the environment favors this type of potential. A broad SLGT risk was maintained for much of AZ into southern UT with the eastern extent out towards the NM/AZ border into the immediate Four Corners, outlining the mean QPF closer to 0.5" from recent forecast. ...Mid-Mississippi Valley... Remnant mid-level disturbance will slowly pivot across AR into MO by Thursday maintaining a consistent posture of targeted mid-level ascent and favoring greater convective coverage under the weak circulation. The pattern is less favorable for more widespread heavy rain prospects, especially those that would warrant more considerable attention and a higher risk like in previous days. Nonetheless, the signal is still there for isolated flash flood potential within portions of the Ozarks up through the mid- Mississippi region near St. Louis. HREF mean QPF shows a general max near the IL/MO border near and north of St. Louis. Expecting this signal to settle somewhere near this area given the favorable 2+ inch PWATs centered over the area. The previous MRGL was expanded north to match the trends in guidance. Kleebauer Day 3 Valid 12Z Fri Jul 17 2026 - 12Z Sat Jul 18 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS MUCH OF WEST TEXAS, SOUTHERN NEW MEXICO, ARIZONA, AND THE SOUTHERN GREAT BASIN... ...Texas into New Mexico... We'll finally see a decay in the heavy rain setup across RGV and Edwards Plateau as the upper pattern evolves to where the mid-level trough over west TX finally caves and begins to dissolve through daytime Friday. Despite that forecast, lingering elevated moisture under the lower heights will allow for at least a scattered threat of heavy convection further northwest into the Permian Basin and Pecos River Valley out in west TX and southeastern NM. Precip totals are considerably lower for the general forecast in the region, however some areas that will have been hit prior will be subject to more rainfall, so the prospects for flash flooding remain elevated for many. Scattered thunderstorms will also continue into the terrain over southwest TX with the greatest focus over the Davis Mtns. Local totals over 2" are projected within the latest ensemble bias corrected output, enough to warrant a continued SLGT risk across the region. Further west into the area of El Paso and southern NM, elevated moisture and lowering heights under the westward progression of the trough to the east will allow for a period of scattered convective activity that could prompt heavy rain for areas that are more susceptible to heavy rain threats. Areas like the Sacramento Mtns. over into the Bootheel are likely to see thunderstorm genesis by Friday afternoon, lingering into the evening before diminishing with the loss of diurnal heating. Already have areas in the Sacramento's still dealing with remnant burn scars from past wild fires, so those area have the greatest threat in this setup to see flash flooding. In coordination with the local El Paso WFO, have expanded the SLGT to include the rest of far west TX into southern NM. ...Western U.S... Despite a weakening presence of the ridge that's been dictating the overall weather pattern for the Western U.S., another active day of widespread convection and locally heavy rainfall will plague the region from southern AZ up through the Great Basin with a northern extension even into parts of western MT. PWAT anomalies out west will remain between the 90-99th percentile according to the latest NAEFS and ECENS climatology with PWATs even encroaching on 2" down by the Mexican border in Pima county. Textbook pattern for monsoonal convection and likely a scattered signal for flash flood potential with the terrain and slot canyons across the interior west being the main focus. Heaviest QPF signature remains over southern UT, the Mogollon Rim and southern AZ with the threat. This is a general repeat from the previous period with the SLGT risk coverage relatively similar as the forecasted convective pattern maintains a similar outlook. ...Ohio Valley through the Great Lakes... Broad theta_E ridge centered over the Ohio and Tennessee Valley's will act as focus for diurnally driven convection during the afternoon Friday, lingering into the evening before finally dissipating with the loss of daytime heating. Further north into the Northern Great Lakes, our next trough will be sweeping across Manitoba into western Ontario with the nose of a prominent jet max associated with the disturbance nudging into the MN Arrowhead and neighboring U.P. Friday night. Expectation is for a blossoming of nocturnally driven thunderstorms to materialize within Arrowhead and neighboring Canada and press southeast as the disturbance migrates southeastward, north of the Great Lakes. Flow will remain generally pretty fast, so the residence time of any convection will be short-lived. However, PWAT anomalies will be pushing upwards of +2 standard deviations according to both the NAEFS and ECENS outputs meaning heavy rain potential is likely with rates between 1-2"/hr likely in the stronger cell cores. MRGL risk remains over both the Great Lakes and Ohio River Valley given the two threats. Kleebauer Day 4 and Day 5 Valid 12Z Sat Jul 18 2026 - 12Z Mon Jul 20 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE WEST ON SATURDAY AND SUNDAY, AND OVER THE OHIO VALLEY INTO SOUTHERN NEW ENGLAND ON SATURDAY... ...Western U.S... A broad active monsoonal pattern will continue across much of the western U.S. Saturday into Sunday. An anomalous PW axis stretching from AZ northward into MT is forecast to remain above the climatological 90th percentile, and locally higher in some spots. This airmass will sustain a localized flash flood threat across an expansive corridor spanning from portions of west TX, AZ, and NM northward to MT. On Sunday troughing over ID/MT should suppress the ridge enough to lower PWs there, and shift the moisture axis southeastward into more of WY and central/western CO. We are carrying Slight risk areas on day 2 and 3 over portions of this region, and some chance embedded Slight risks will eventually be needed on day 4 and/or 5 as well. There should be plenty of moisture and CAPE across the risk area to support heavy rainfall rates and a localized flash flood risk. However, the mesoscale details which may end up determining the eventual flash flood coverage can not really be pinned down at this lead time, and ensemble QPF is a bit lower compared to day 2 and 3. Thus will hold at Marginal and continue to monitor. ...Ohio Valley into Southern New England... On Saturday the core of the high PW airmass shifts eastward, with 2"+ PWs forecast from portions of the Mid-Atlantic into Southern New England. Troughing building into the Northeast, accompanied by embedded shortwave energy and favorable right entrance jet dynamics, should support a organized convective threat from OH into the northern Mid-Atlantic and possibly portions of the Northeast. The Marginal risk was expanded northward into more of NY and Southern New England with this update. Spatial uncertainties exist regarding how far north the surface front and axis of better instability will get, which will ultimately dictate the northern bound of any flash flood risk. Overall this should be a progressive system, although the eventual evolution could support a couple rounds of convection. Given the high PWs combined with strong 850mb moisture transport and synoptic forcing...at least a localized rainfall rate driven flash flood threat exists. We may eventually need a targeted Slight risk as the event nears and confidence on convective evolution and rainfall axis increases. Further south and west across the OH Valley into the southern Mid- Atlantic large scale forcing may be weaker, but plentiful moisture and instability may still drive localized areas of heavy rainfall. ...Florida... Watching the potential for heavy rainfall across the west coast coast of FL this weekend with multiple models showing a mid-level weakness developing over the eastern Gulf in between two strong ridges. This setup would support a heavy rainfall threat, and possible low pressure development. However, run to run model consistency has not been great, and any flash flood threat over FL will depend on if and exactly where this low to mid level circulation sets up (heavier rain could stay primarily offshore). Thus we will hold off on introducing any Marginal risk area at this time and continue to monitor trends. Chenard Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt $$