FOUS30 KWBC 090755 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 255 AM EST Mon Nov 9 2026 Day 1 Valid 12Z Mon Nov 09 2026 - 12Z Tue Nov 10 2026 ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF FAR SOUTHEASTERN TEXAS... The setup that brought significant rainfall to portions of South Texas will continue through the mornings hours today with a gradual decay in the heavy rain potential by late-afternoon and beyond. Upper level pattern across the Southern Plains continues to favor focused large scale forcing within the underside of a broad, positively tilted trough centered over Chihuahua and adjacent southwest TX. At the surface, a well-defined surface trough bisects South TX with a enhanced convergence signature focused almost perfectly between the RGV to the west and the Western Gulf to the east. This has allowed for repeated convection to navigate out of Mexico and funnel up into the area to provided an incessant nature of moderate to heavy rainfall capable of producing local flash flood impacts through this evening. By the morning, the overall synoptic pattern will slowly evolve with the surface trough pivoting to the southeast with the surface boundary becoming more confined to the South TX coastal plain. There's a reasonable agreement within the CAMs suite of a narrow axis of heavy rainfall centered between areas just south and southwest of Corpus Christi down towards Brownsville with its orientation and convective premise narrowed down into the surface trough positioning. Model forecast soundings within the zone of expected impact have a textbook signature for enhanced low-level convergence and relatively solid directional shear with magnitudes between 30-40kts in effective boundary layer shear. This would coincide with local mesocyclone development and maintenance with generally slower storm motions as referenced via the bunkers right outputs hovering between 4-10kts at peak speeds during the morning and early afternoon time frame. This would set the stage for slow-moving cells that could dump appreciable rainfall over the course of several hours before finally vacating, and/or decaying with the evolving pattern shifting the ascent pattern further downstream, putting an end to the threat. Some areas have already seen 4-9" of rainfall over the past 24 hrs, so area FFG's are fairly compromised, especially within the zone encompassed between the southwestern side of Corpus Christi to about 50 miles east of Laredo. The area to the southwest of Corpus Christi near Kingsville was the epicenter of the heavy rain episode this past afternoon with local totals ranging from 5-10" noted within obs and MRMS gauge corrected data. This area in particular is a highlight within the expected forecast evolution as models note this area being part of the convective scheme for the first half of the new D1. Solid FFG exceedance probabilities for both 1 and 3-hr intervals within the latest 00z REFS indicate a heightened threat for the above area with modest upticks even down into Brownsville proper as rainfall totals between 2-4" this past period also provided reasonable saturation to the top layer of soils to accompany the already more sensitive urban fixture over the lower RGV. Neighborhood probs for >3" are running a modest 25-45% in that zone between southwest Corpus Christi down to Brownsville, highlighting the most probable areas for where anchored/training convection could transpire. Given the above outputs and current sensitivities from the previous period of rainfall, and in coordination with the Corpus Christi and Brownsville WFO's in the region, went with a targeted SLGT risk upgrade into that aforementioned area for the new D1 time frame. The MRGL was also expanded a bit further north to cover for the secondary max positioned over south-central TX into Hill Country to the west of I-35. Guidance has a small area of potentially up to 2-3" additional rainfall outside the primary setup further southeast, and that would fall on top of the widespread 2-5" that occurred the past 24 hrs, as well. Expectation is for a degraded setup by late-afternoon today and finally and end to the heavy precipitation potential prior to 00z allowing the threat to wane. Kleebauer Day 2 Valid 12Z Tue Nov 10 2026 - 12Z Wed Nov 11 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Kleebauer Day 3 Valid 12Z Wed Nov 11 2026 - 12Z Thu Nov 12 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Kleebauer Day 4 and Day 5 Valid 12Z Thu Nov 12 2026 - 12Z Sat Nov 14 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley 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 $$