Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jul 31 2023 08:19:35 FOUS30 KWBC 310819 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 418 AM EDT Mon Jul 31 2023 Day 1 Valid 01Z Mon Jul 31 2023 - 12Z Mon Jul 31 2023 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS THE SOUTHWEST TO CENTRAL HIGH PLAINS, THE MID MISSOURI TO MID MISSISSIPPI VALLEYS, AND OVER PORTIONS OF THE FLORIDA PENINSULA... ....Southwest to the central High Plains... Above normal moisture will continue to be present across portions of the Southwest, particularly portions of Arizona today but also extending northward toward portions of the Central High Plains/Central Rockies. First, moisture anomalies peak near 2-3 standard deviations above normal today across portions of Arizona which combined with expected daytime heating/instability should produce higher coverage of storms and intensity compared to recent days. This is supported by the various CAMs and the 00Z HREF which shows peak 0.5" hourly total probabilities this afternoon at 60-80 percent from northern AZ into far southern UT. This raises the concern for isolated flash flooding for both urbanized areas and complex terrain. Across portions of Colorado and Wyoming, shower/thunderstorm activity is expected to be enhanced with approaching shortwave energy timing during the peak of the afternoon. Localized hourly totals up to 1-1.5" will be possible, especially by early evening as storms move east off the terrain into the foothills and Plains. ....Mid Missouri to the Mid Mississippi valley... Current convection across portions of the Plains early this morning will continue to move southeast in the northwest flow regime, rounding the periphery of the strong upper ridge axis centered over Texas. This activity will move along/northeast of a stalled frontal boundary in the region and act on the southwesterly low-level jet with upwards of 30-35 kts of inflow at 850 mb. As the main complex of storms moves southeast, additional convection is likely to develop ahead of it across portions of far eastern KS and much of Missouri. Hourly totals exceeding 1" will be possible with the strongest cores this morning, resulting in a localized flash flood threat. Additional convection is expected to develop late this evening into tonight (early Tuesday morning) across portions of the region, as the low-level jet increases, and some of this rainfall may overlap, particularly across portions of northern MO as supported by the 24-hr HREF probabilities of 3"+ which reach 30-40 percent. The environment will be certainly conducive for training, highly efficient rain producing thunderstorms that could produce localized but higher totals. If the trends toward a higher end heavy rainfall threat continue to grow for tonight across central Missouri, an upgrade to Slight Risk could be needed. ....Eastern Florida Peninsula... Continued deep moisture present across Florida, characterized by precipitable water values exceeding 2" (near 1.5-2 standard deviations above normal) will interact with a stalled frontal boundary to the north to enhance the daily afternoon/evening thunderstorm coverage and intensity today. Hourly totals between 1-2" will be possible during the peak heating this afternoon/evening, supported by the 00Z HREF neighborhood probabilities for 2" in 1-hr peaking at 40-70 percent across the eastern Florida Peninsula. This supports the potential for localized flash flooding for mainly the urban locations. Taylor Day 2 The Day 2 outlook will be updated by 0830Z. Day 3 The Day 3 outlook will be updated by 0830Z. Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9zbya68jKwTolnn8Utm9gQig-Yp2VWyeSNNkMJp9zyUu= GkKwkFbDXCirhYmLuHbH7tDnGvZtSGdQjy-lDw_nOuUq9ls$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9zbya68jKwTolnn8Utm9gQig-Yp2VWyeSNNkMJp9zyUu= GkKwkFbDXCirhYmLuHbH7tDnGvZtSGdQjy-lDw_nnruFXXE$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9zbya68jKwTolnn8Utm9gQig-Yp2VWyeSNNkMJp9zyUu= GkKwkFbDXCirhYmLuHbH7tDnGvZtSGdQjy-lDw_nCXX7Mg4$=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) .