Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Apr 19 2023 20:16:51 FOUS30 KWBC 192016 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 416 PM EDT Wed Apr 19 2023 Day 1 Valid 16Z Wed Apr 19 2023 - 12Z Thu Apr 20 2023 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR AN EASTERN PORTION OF THE CENTRAL PLAINS... Round 1 of activity continues over WI this afternoon ahead of an impulse over MN/IA with locally heavy rain generally moving out of the areas with snowpack. A stronger impulse currently over CO shifts over the central Plains this evening, riding a cold front currently pushing south over western KS that will stall this afternoon. Round 2 of activity is ahead this cold front over the eastern portions of the Central Plains (southeast Neb/northeast KS) this evening with initiation after 00Z. One or two rounds of activity occurs over this area spreading into southwest IA/northwest MO before expanding southwest to northeast through the night from eastern Kansas through Wisconsin. PW of 1.25" is 2 sigma above normal. A Slight Risk area has been raised for far southeast Neb/northeast KS/southwest IA and far northwest MO. The new 12Z HREF still depicts a risk for rainfall rates over 1"/hr. While KS/Neb/IA/MO will have the most instability this evening, antecedent conditions are also favorable for flash flooding in Wisconsin due to added snowmelt from the recent winter storm over the western half of the state. Thus if FFG is able to be exceeded, we could realize some lower end flood impacts, especially over any more susceptible areas. The Marginal Risk area was expanded west a bit for activity over southeast Neb and trimmed on the eastern end per 12Z CAM trends. Jackson Day 2 Valid 12Z Thu Apr 20 2023 - 12Z Fri Apr 21 2023 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF NORTHEAST TEXAS TO THE MID-SOUTH... Deep-layer Gulf moisture streams up across Texas until a cold frontal passage early Friday. PW values of 1.75 inches (1.5 to 2 sigma) will spread over central/eastern Texas through Arkansas and the Mid-South by Thursday afternoon ahead of the frontal boundary as it approaches. Continued southwesterly deep layer flow will be nearly parallel to the front, bringing the risk for repeating and backbuilding storms. 12Z consensus for areal averages of 1 to 3.5 inches from the Heart of Texas (The I-35 corridor between Austin and Dallas) to southeast Missouri with amounts generally an inch or less for the Upper Mississippi Valley and Great Lakes, though FFG will remain lower there due to recent rains (and snowmelt in WI), thus keeping an elevated threat for flooding concerns. The Slight Risk area was expanded a bit more, further southwest into central Texas and northeast into southern Illinois. The southern bounds of the Marginal Risk ares was also expanded south and eastward to include the Houston metro and farther into western Louisiana to account for convergent activity with otherwise progressive prefrontal thunderstorm lines. Jackson Day 3 The Day 3 outlook will be updated by 2030Z. Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5dbVwtHNqlA-UZ4qJNDpTgnfOkfDU8kvYB_aL0D8JQEN= 0BNcUzu1s2hAOAL-cWfvDY93XBIxzTvDY3rod5hLHNUzw4A$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5dbVwtHNqlA-UZ4qJNDpTgnfOkfDU8kvYB_aL0D8JQEN= 0BNcUzu1s2hAOAL-cWfvDY93XBIxzTvDY3rod5hLnGG4GKg$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5dbVwtHNqlA-UZ4qJNDpTgnfOkfDU8kvYB_aL0D8JQEN= 0BNcUzu1s2hAOAL-cWfvDY93XBIxzTvDY3rod5hL97RlgGo$=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .