Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jun 24 2023 08:07:10 FOUS30 KWBC 240807 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 406 AM EDT Sat Jun 24 2023 Day 1 Valid 12Z Sat Jun 24 2023 - 12Z Sun Jun 25 2023 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS MUCH OF MINNESOTA AND THE EASTERN DAKOTAS... ....Northern Plains into Northern Minnesota...' Early this morning an anomalously deep mid/upper level low is positioned over Montana and is expected to reach the Upper Midwest by late tonight and early Sunday morning. Meanwhile a surface low is expected to lift northward into the eastern Dakotas later this evening. With higher moisture characterized by dewpoints in the 60s and PWs above 1.25-1.5" wrapping into the system, a narrow corridor of heavy rainfall expected near the surface low where the best overlap of moisture, some instability, and deep forcing is present. The latest 00Z HREF shows a strong signal for 2-3"+ across portions of the Dakotas and hourly totals between 1-1.5" will be possible. For portions of Minnesota southward into Midwest, early morning convection should push through portions of Iowa and then additional convection is expected to develop in the afternoon/evening across Minnesota but also perhaps extending southward into Missouri, though there is more uncertainty in how convection develops that far south. Overall, not a lot of change from the previous issuance with the best signal for isolated to scattered flash flooding across portions of Minnesota and the eastern Dakotas. ....Northeast... The slow moving, stubborn upper level trough will inch forward during the day, beginning this morning in the Ohio Valley and reaching New England by early Sunday morning. The combination of anomalous moisture (PWs up to 1.5"+), warm cloud depths, and skinny CAPE profiles, efficient rainfall producing showers and thunderstorms will be capable of producing localized heavy rainfall, especially this afternoon/evening with the peak daytime heating. With the mean flow remaining somewhat parallel to the overall storm motions, some repeating rounds will be possible, supporting isolated/localized instances of flash flooding. ....Southeast Florida... A deep axis of higher than normal moisture will position itself across South Florida and with weak flow and modest shear, higher coverage of afternoon/evening thunderstorms are expected to develop. The environment will support intense rain rates given the tall/skinny CAPE profiles and warm cloud depths. The latest guidance suggests the greatest convection may end up developing just inland away from the highly urbanized corridor, but there's enough ingredients and support in the various models to maintain the Marginal Risk in the ERO. ....Central Washington... Isolated thunderstorms this afternoon will have the potential to produced localized rain rates up to 0.5-1.0"/hr per the latest model guidance and 00Z HREF neighborhood probabilities. Given some of the burn scars in the area, particularly western Okanogan County burn scars - Cedar Creek, Cub Creek, and Muckamuck - and the potential for heavy rainfall, a Marginal Risk was introduced in coordination with WFO OTX. Taylor/Bann 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!48aljmqe7sMU3YVq-lpthRYu4fulf3p_WmCRFLgquKgN= sk8WXPIYGGiWDH9VIqjL4hEnaeHcDRpt17wINVj2J8Kqg5I$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!48aljmqe7sMU3YVq-lpthRYu4fulf3p_WmCRFLgquKgN= sk8WXPIYGGiWDH9VIqjL4hEnaeHcDRpt17wINVj2EEMFTh4$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!48aljmqe7sMU3YVq-lpthRYu4fulf3p_WmCRFLgquKgN= sk8WXPIYGGiWDH9VIqjL4hEnaeHcDRpt17wINVj2whWIHDw$=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) .