Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 22 2025 07:32:06 AWUS01 KWNH 220732 FFGMPD ARZ000-OKZ000-221300- Mesoscale Precipitation Discussion 1115 NWS Weather Prediction Center College Park MD 331 AM EDT Mon Sep 22 2025 Areas affected...Eastern Oklahoma...Western to Central Arkansas... Concerning...Heavy rainfall...Flash flooding possible Valid 220730Z - 221300Z SUMMARY...Area of concern will remain in favorable region for upstream redevelopment and repeat track clusters of storms. Rates to 1.5"/hr and spots of 2-3.5" suggest an incident or two of localized flash flooding is possible through daybreak. DISCUSSION...GOES-E WV suite denotes compact shortwave at base of broader scale long wave trough is exiting south-central MO, with trailing confluence trough through the low to mid-levels lingering across west-central AR into far eastern OK. A few stronger clusters with rates of up to 1.5"/hr and similar localized totals have been noted along this axis for much of the overnight period, helping to saturate the upper soil profiles and locally reduce FFG. However, recent 3.9um/10.3um IR loops show increasing mid-level cloudiness and agitated shallow convective environment across the upstream edge of the ongoing clusters. RAP analysis denotes a weakening cap with CINH reducing below 15 J/kg across western AR into far Northeast TX, generally coincident with instability and low to mid-level confluence axis. While, lapse rates are limited, low level theta-E remains and supports 1000-1250 J/kg of MLCAPE trough this area and points west. CIRA LPW and RAP analysis also note the deeper layer moisture axis further west within the broader southwesterly 25-30kt LLJ across central to eastern OK, though overall deep layer confluence also depicts a pool of moisture to 1.7" along the best convergence over western AR. Aloft, the speed max of the subtropical jet is reaching the apex of the ridge further upstream over CO, but the exit of the jet is digging southward across central OK/NE TX, resulting is broadening left exit divergence to support upstream redevelopment and slow veering of the LLJ further increasing low-level convergence. As such, expectation for further upstream development is expected for the next 3-6hrs. Deep layer steering mean flow is toward the northeast as the shortwave exits, however, the strength of the approaching jet has sharpened the 500-1000 thickness ridge to the west and propagation vectors are starting to turn upstream to the low-level inflow, bending the storm track vectors more west to east. This should allow for upstream thunderstorm clusters that do develop to once again track through areas recently saturated.=20 Rates of 1.5"/hr and potential for additional 2-3" totals suggest scattered incidents of localized flash flooding are becoming increasingly possible through the remainder of the overnight period. There remains some uncertainty to the latitude of the redevelopment, but any activity further north will also intersect areas saturated over the last two nights as well into NW, north-central AR.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8BblS9xxEqPsw_KBtK_DrEPLT3ltN387XEmCj8W7t-snZuSyK92wcWmOEthTaSIkNEDq= WcUO_g9tzGv6ePFuxOJ77HY$ for graphic product... ATTN...WFO...LZK...TSA... ATTN...RFC...ORN...TUA...NWC... LAT...LON 36169515 36049332 35769228 35319175 34679197=20 34509246 34509322 34699424 35039523 35669561=20 =20=20=20=20=20=20=20=20=20=20=20=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .