Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jan 05 2023 08:31:30 FOUS30 KWBC 050831 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 330 AM EST Thu Jan 05 2023 Day 1 Valid 12Z Thu Jan 05 2023 - 12Z Fri Jan 06 2023 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF CALIFORNIA... A strong cold front and atmospheric river continues to bring periods of heavy rain to a good chunk of California this morning. That rain will continue through much of the day today as various waves of rainfall move inland and sweep northwest to southeast across the state. The most consistent and heaviest rain is with this initial round of rain moving across the Central Valley and approaching southern CA. CAMs guidance shows a renewed round of occasionally heavy rain moving into the northern CA coast later this morning, followed by off and on shower activity through much of the day. A short break from the rain is expected overnight tonight statewide. This second round of rain is expected to impact the Central Valley north and not make it significantly into SoCal. The threat in SoCal is the nearly orthogonal flow of the rainfall into the Transverse Ranges especially, but with some impact into the Peninsular Ranges as well. Wegman Day 2 Valid 12Z Fri Jan 06 2023 - 12Z Sat Jan 07 2023 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF CALIFORNIA... ....20:30z update... Minor changes were made to the marginal or slight risk areas from the overnight issuance. Slight risk along the southern Sierra foothills was expanded southward to account for additional burn scars. ....Previous discussion... ....California... Axis of deeper onshore flow and moisture advection will continue to translate, south bringing the threat for heavy precipitation through the remainder of the Transverse Ranges and into the Peninsular Ranges of Southern California, with some additional heavy amounts expected along the Sierra foothills as well. A Slight Risk was maintained for both areas.=20 A Slight Risk was also placed along parts of the Northern California coast, where some of the heaviest amounts in the Day 1 period are expected. While widespread additional heavy amounts are not expected, some enhanced forcing and moisture advection just ahead of the low as it lifts north along the Oregon coast may support some localized heavier amounts, especially in the terrain on Thursday. And given the anticipation of very heavy amounts across this region, there are concerns that even additional light to moderate amounts may accentuate any ongoing runoff concerns across the region. Kebede/Pereira 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!5QspcepvfoQ8vARRg6f4kifqOQ2MKKQf1uod9r9G5Dvr= lt5Tjch9jGLHKbLCy-gt8WQatHNzo2fF5T5nT3Qs9RUgZU8$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5QspcepvfoQ8vARRg6f4kifqOQ2MKKQf1uod9r9G5Dvr= lt5Tjch9jGLHKbLCy-gt8WQatHNzo2fF5T5nT3QsC29Rxas$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5QspcepvfoQ8vARRg6f4kifqOQ2MKKQf1uod9r9G5Dvr= lt5Tjch9jGLHKbLCy-gt8WQatHNzo2fF5T5nT3QsvZH88GQ$=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) .