Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Feb 08 2025 20:15:45 FOUS30 KWBC 082015 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 315 PM EST Sat Feb 8 2025 Day 1 Valid 16Z Sat Feb 08 2025 - 12Z Sun Feb 09 2025 ....16Z Update... ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR MUCH OF WEST VIRGINIA... No changes were made to the ongoing Marginal Risk area across West Virginia. Recent rainfall has made the soils there saturated. However, rainfall rates have all been at a half inch per hour or less across the area. Thus, any flooding has been from areal river rises as rates have not been high enough to cause flash flooding. A slow-moving warm front in the area has been the cause for the rainfall. The rain will lift north this afternoon as the state gets into the warm sector. This evening, the cold front will move through that could cause heavier rain, albeit with fast moving convection. The greatest threat for isolated flash flooding will occur with any training heavier showers, and a thunderstorm or two can't be ruled out. The front will sweep through by around midnight, ending the flooding threat due to rainfall, though rises from draining streams and creeks will continue through the night and into the day on Sunday. Wegman ....Previous Discussion... ....West Virginia... Strong N-S quasi-zonal mid and upper level flow will be perturbed a bit during Day 1 (12Z Sat-12Z Sun) as a 150+ kt upper level jet streak traverses the Upper Midwest and Ohio Valley, while a flat 500 mb vort lobe pushes across the Lower Great Lakes. Broad-scale exit region forcing associated with the upper jet axis will surge southwesterly low-level inflow ahead of the surface frontal wave, with 850 mb moisture flux anomalies peaking between 4-5 standard deviations above normal later this afternoon into Sat night, while TPW values peak around 1". Robust synoptic-scale support and low- level moisture transport will be offset somewhat by the weak elevated instability, with MUCAPEs generally less than 500 J/Kg. Nevertheless, even though not advertised on the latest (00Z Sat) HREF, the aforementioned dynamic and thermodynamic ingredients will be sufficient for spotty hourly rain rates of 0.5"+ and 3-hourly rates of 1.0"+, with localized event totals between 1.5-2.0"+. Current 3-hr flash flood guidance values remain quite low (1" or less) across the outlook area, which includes much of WV. Despite the lack of instability, the low FFG values could be exceeded over isolated areas with 2 consecutive hours of 0.5"+/hr rainfall rates. Since the soils in these areas are saturated, and the terrain is rugged, we have maintained the Marginal Risk area for much of WV (outside of its northern or eastern Panhandles). Hurley/Roth Day 2 Valid 12Z Sun Feb 09 2025 - 12Z Mon Feb 10 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Pereira Day 3 Valid 12Z Mon Feb 10 2025 - 12Z Tue Feb 11 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Pereira Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-pDEXQQSpZOHzi4YeF6tjVSu9n_I-DQW6DG-c1Qi_X8_= f14OTTRQvycB7v5knsjZJyIaM2deIuv9h600YDEW3dsoPvg$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-pDEXQQSpZOHzi4YeF6tjVSu9n_I-DQW6DG-c1Qi_X8_= f14OTTRQvycB7v5knsjZJyIaM2deIuv9h600YDEWgfLQHEo$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-pDEXQQSpZOHzi4YeF6tjVSu9n_I-DQW6DG-c1Qi_X8_= f14OTTRQvycB7v5knsjZJyIaM2deIuv9h600YDEWKkmyRGs$=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .