Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Feb 03 2024 07:53:52 FOUS30 KWBC 030753 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 253 AM EST Sat Feb 03 2024 Day 1 Valid 12Z Sat Feb 03 2024 - 12Z Sun Feb 04 2024 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE CENTRAL CALIFORNIA COAST RANGES AND FROM THE UPPER COAST OF TEXAS, EASTWARD ACROSS SOUTHERN LOUISIANA AND FAR SOUTHERN MISSISSIPPI... ....Central Gulf Coast into the Lower Mississippi Valley... The latest hi res guidance is showing similar evolution to the current organized areas of convection over the Southern Plains in the post 1200 UTC Sat period. There has already been weakening to the earlier well defined north to south squall line that was moving across south central OK into north central TX, with this area of convection expected to continue to weaken towards the beginning of the upcoming day 1 period as it pushes out of eastern OK/northeast TX and into western AR/northwest LA. At the same time the enhancing convection over South Texas is expected to become the primary convective area, pushing off the mid to upper TX coast and into southern LA at the beginning of the day 1 period. Overall, both areas of convection should remain fairly progressive, continuing to be a detriment to very heavy totals.=20 This continues to be illustrated in the latest HREF hourly probabilities for .50" and 1"/hr amounts. The .50"/hr probabilities remain high across southern LA through much of the day 1 period as the convection moves east, but the 1"+ probabilities are much lower along the immediate coast, indicative of the expected progressive nature. Similar to the past few model cycles, concerns are that the heaviest rains with the coastal convection will stay out over the open Gulf of Mexico well to the south of southern LA. This is shown in the HREF 1"/hour probabilities that have the highest probabilities well south of southern LA. Given the above, we continue to believe the slight risk is a low end slight for southern LA, outside of any urban issues that may develop in New Orleans. No significant changes made to the previous outlook area for the upcoming day 1 period ....Central California Coast... The beginning of the next atmospheric river event for central to southern California will arrive late day 1 with IVT values of 500 - 600 kg/m/s impacting coastal central California in the 0600-1200 UTC period. HREF neighborhood probabilities for 1 and 2"+ amounts ending at 1200 UTC Sun are high in the max onshore flow/IVT area.=20 This fits well with where the previous slight risk was depicted.=20 For the entire next AR event, the risk is much greater than slight across this region, but the timing is such that for the period ending 1200 UTC Sunday only a slight risk is warranted, with much heavier precip and excessive rainfall risks after the upcoming day 1 period. Oravec 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!6QQdzMgXv5i69FPWhwDegUg3KykeZeVsmqQtClK9qPSp= PiQOoiGbHvRLP72tI37RdbqM_aX7R52R_dMmjQ_Kl0coFsw$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6QQdzMgXv5i69FPWhwDegUg3KykeZeVsmqQtClK9qPSp= PiQOoiGbHvRLP72tI37RdbqM_aX7R52R_dMmjQ_KkuAKNXI$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6QQdzMgXv5i69FPWhwDegUg3KykeZeVsmqQtClK9qPSp= PiQOoiGbHvRLP72tI37RdbqM_aX7R52R_dMmjQ_KCkJLZJE$=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) .