Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 11 2023 08:10:26 FOUS30 KWBC 110810 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 409 AM EDT Wed Oct 11 2023 Day 1 Valid 12Z Wed Oct 11 2023 - 12Z Thu Oct 12 2023 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG PORTIONS OF FLORIDA AND THE MIDWEST... ....Southeast... A surface wave developing over the western the Gulf of Mexico this morning is forecast to track quickly east-northeast across the northern Gulf to the Southeast Coast this period. Deep southwesterly flow ahead of the wave will feed tropical moisture into a boundary lifting north through the northern Gulf. Guidance shows the northern edge of 2+ inch PWs lifting across Florida and the central Gulf Coast into southern Georgia. While there remains some model disagreement regarding the timing and amplitude of the system, most guidance agrees that the heaviest amounts will remain offshore along with the greater instability. An axis of relatively heavier amounts is expected near the track of the low, which is forecast to move inland near Apalachee Bay and then track east-north across North Florida early Thursday. Convection developing along a trailing front may contribute to some additional heavy amounts late in the period. The Marginal Risk highlights the area where the HREF shows higher probabilities for accumulations of 3 inches or more. For areas near Tampa Bay and east, the HREF does show some low probabilities for meeting or exceeding 3 hour FFGs, but these appear to be largely influenced by the FV3 which seems to be both a heavier and more southerly outlier in comparison to the other HREF members. Therefore, opted to go with only a Marginal Risk at this point.=20 Farther to the north, and well north of the wave, most models show a stripe of strongly-forced stratiform rain developing from the central Gulf Coast northeastward into central Georgia and southern South Carolina. Expect the lack of instability and high FFGs to limit any impacts across that region. ....Eastern Nebraska to northern Indiana... The threat for heavy rainfall is expected to increase across this area as a strengthening low level jet ahead of a developing closed low in the West begins to support pooling moisture along a slow-moving boundary. As PWs climb to around 1.25 inches, persistent, strong inflow into an area of sustained lift may support redeveloping storms along boundary. The Marginal Risk highlights an area where the HREF shows high probabilities for accumulations of 2 inches or more, with the highest probabilities centered over west-central Iowa and east-central Iowa through northern Illinois.=20 Pereira 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!8s1tEx_NFxhqeTjF9kyPdH8VKvtnj3EXG-ja2UfzJMo9= ERB4DIslh8UEmdNyDaqxuNZ8GK5SLPhp4VIlQkmD84UuOuo$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8s1tEx_NFxhqeTjF9kyPdH8VKvtnj3EXG-ja2UfzJMo9= ERB4DIslh8UEmdNyDaqxuNZ8GK5SLPhp4VIlQkmDyw2XxOk$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8s1tEx_NFxhqeTjF9kyPdH8VKvtnj3EXG-ja2UfzJMo9= ERB4DIslh8UEmdNyDaqxuNZ8GK5SLPhp4VIlQkmDH-QyR7w$=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) .