Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jan 16 2023 08:15:24 FOUS30 KWBC 160814 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 313 AM EST Mon Jan 16 2023 Day 1 Valid 12Z Mon Jan 16 2023 - 12Z Tue Jan 17 2023 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF CENTRAL AND SOUTHERN CALIFORNIA AND CENTRAL ARIZONA... ....Southern and Central California... Additional height falls will be pushing inland day 1 into central to southern California continuing localized heavy rainfall potential through at least the first half of the upcoming forecast period. No changes made to the previous two marginal risk areas over California, one from the Peninsular Range west to the coast, including the eastern portions of the Transverse range and the second across central California in the upslope of the central to southern Sierra. For the southern marginal risk area, the threat appears to be for the first few hours of the day 1 period when ..25"+ hourly rates are possible. This may add up to an axis of 1"+ rains from the eastern portions of the Transverse Range, south through the Peninsular Range, with HREF neighborhood probabilities for 1"+ amounts high, 60-90% across these areas. By late morning, the anomalous pw axis will have shifted farther south into northwest Mexico with any additional showers likely to have hourly rates maxing out around .10". Given elevated stream flows from recent heavy rains, additional runoff issues are possible early day 1. For the northern precip area in the upslope of the Central to Southern Sierra, precip may be more prolonged, supporting .25-.50" hourly precip amounts into late morning, followed by a second period of showers Monday afternoon as a second area of height falls push off the Pacific into Central California. Hourly rates not expected to be as great with the second period of rains,=20 mostly .10"+. Similar to the areas across Southern California, additional runoff issues possible across areas where stream flows are high and soils saturated from recent heavy rains. ....Central Arizona... An axis of above average PW values, 2 to 3+ standard deviations above the mean, will persist across central to southern Arizona day 1. Favorable upslope flow of the anomalous PW values into the Mogollon Rim will support persistent showers for most of the upcoming day period. While hourly rates are expected be generally below .25", the prolonged showers conditions will support a concentrated axis of 1"+ totals day 1 across south central Arizona in the upslope of the Mogollon Rim. With stream flows mostly near normal across this area, the threat level was maintained at marginal. 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!5WQq4Bvvhi9lbJ6TaRjmkJV2p4U8UNIzAv2XsYxWJZdY= b8As1e8J7bsSf2JI3yzwHpE6vPQp_d96TQB08WLL6Vz3P3s$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5WQq4Bvvhi9lbJ6TaRjmkJV2p4U8UNIzAv2XsYxWJZdY= b8As1e8J7bsSf2JI3yzwHpE6vPQp_d96TQB08WLL_RtQ98w$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5WQq4Bvvhi9lbJ6TaRjmkJV2p4U8UNIzAv2XsYxWJZdY= b8As1e8J7bsSf2JI3yzwHpE6vPQp_d96TQB08WLLO17WEUU$=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) .