Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Feb 02 2024 08:05:33 FOUS30 KWBC 020805 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 304 AM EST Fri Feb 02 2024 Day 1 Valid 12Z Fri Feb 02 2024 - 12Z Sat Feb 03 2024 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS EASTERN PORTIONS OF THE SOUTHERN PLAINS TO THE MIDDLE AND UPPER TEXAS COAST... The latest model guidance remains consistent with the increasing shower/thunderstorm activity across the Southern Plains Friday afternoon/evening as strong height falls push through the Southwest and into the Southern High Plains. PW values expected to continue to increase day 1 ahead of these height falls as low level southerly flow strengthens off the western Gulf and spreads northward into the Southern Plains. The well defined upper difluence ahead of these height falls and the axis of increasing PW values will support potential for areas of heavy rains. There continues to be a lot of spread with where the heaviest totals will occur. This is illustrated well with the HREF neighborhood probabilities showing a large area of high probabilities for 1"+ totals across central to eastern Texas, northward into portions of southeast to western Oklahoma and south central Kansas. However, the EAS probabilities for 1"+ amounts day 1 are much lower indicating poor overlap in the latest hi res models. The previous marginal risk area still fits the geographical spread in the latest guidance, leading to no changes at the moment in the marginal risk area. No changes also to the risk level given the current spread in qpf details and consensus that any precip will be generally to the northwest of where the heaviest amounts have occurred over the past few weeks. Oravec Day 2 Valid 12Z Sat Feb 03 2024 - 12Z Sun Feb 04 2024 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM EAST TEXAS INTO PORTIONS OF THE LOWER MISSISSIPPI VALLEY/CENTRAL GULF COAST... ....Central Gulf Coast into the Lower Mississippi Valley... The expanding convection across eastern Texas at the end of day 1, will continue to push eastward day 2 across the Central Gulf coast and toward the Lower Mississippi Valley. Overall favorable conditions continue for heavy rains day 2 with well defined upper difluence spreading east in an axis of strong southerly onshore flow off the Gulf and PW values of 1 to 1.5". There is better model agreement, however, that the heaviest qpf axis will be closer to the Gulf coast, where instability will be better.=20 Subsequently, we have trimmed the northern end of the previous slight risk area by about 150-175 miles. In the area where the slight risk was removed, rainfall has been less over the past week compared to previous weeks. This is evident in many of the USGS sites that show river gauge heights lowering over the past week.=20=20 Closer to the Gulf coast where the heaviest qpf is expected, the convection will still be fairly progressive. There still is the potential for the convection to be offshore of the central Gulf coast, but with still enough models showing heavy precip across southern LA into far southern Mississippi, did not want to remove the slight risk entirely. The marginal risk area extending northwestward into Arkansas, eastern Oklahoma, eastern Kansas and far southwest Missouri, was narrowed from the previous issuance to better match the narrow axis of moderate to locally heavy precip totals. ....Central California Coast... The previous marginal risk area was expanded to the north by approximately 80 miles to cover the spread of qpf that falls by the end of day 2 associated with the next atmospheric river event. All models are in agreement that the heaviest rainfall amounts will be during the day 3 period. However, with recent heavy rains across this area and potential for additional heavy rains to start by the end of the day 2 period, a marginal risk of runoff issues is warranted. Oravec 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!9VD76LzqArDTn5MYLmM5qPGRWon1kNNwe4YP4GJpSi5a= bM7jgb83x0f2WIGfTCquliydX66zlm_q0dpNseIxjZATjws$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9VD76LzqArDTn5MYLmM5qPGRWon1kNNwe4YP4GJpSi5a= bM7jgb83x0f2WIGfTCquliydX66zlm_q0dpNseIxq5JYUes$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9VD76LzqArDTn5MYLmM5qPGRWon1kNNwe4YP4GJpSi5a= bM7jgb83x0f2WIGfTCquliydX66zlm_q0dpNseIx95ZwCPI$=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) .