Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Oct 20 2025 19:38:01 FOUS30 KWBC 201937 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 337 PM EDT Mon Oct 20 2025 Day 1 Valid 16Z Mon Oct 20 2025 - 12Z Tue Oct 21 2025 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS INTERIOR NEW ENGLAND... 16Z update... The latest guidance depicts an uptick in QPF across northwest portions of Vermont; which resides just outside of the current Marginal Risk area over northern New England. A minor westward nudge of the western boundary was made across northwest Vermont to reflect this trend. Elsewhere looks to be in good order. Campbell Anomalous PW (1.5-2.5 standard deviations above the mean) and 850-700 mb moisture flux(3-5 standard deviations above the mean) values will accompany the strong cold/occluded frontal boundary that will sweep northeastward through New England Monday. Hi res models all show an uptick in hourly rainfall amounts along and ahead of this front beginning shortly after 1200 UTC. Both the HREF and RRFS neighborhood probabilities are high for hourly totals in the .50-1" range as the front sweeps northeastward on Monday. Concerns continue for isolated runoff issues where the anomalous 850-700 mb moisture flux will produce strong upslope flow across much of VT, NH and into western ME. Across these areas both the HREF and RRFS neighborhood probabilities are high for 2"+ total amounts during day 1. Overall, only some minor changes made to the previous marginal risk area. Oravec Day 2 Valid 12Z Tue Oct 21 2025 - 12Z Wed Oct 22 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Campbell Day 3 Valid 12Z Wed Oct 22 2025 - 12Z Thu Oct 23 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. ....Lake Erie vicinity... A strong low positioned north of the Great Lakes region will sustain an occluded surface front that will support stronger lower level flow across the Lakes leading to locally enhanced=20 precipitation. Lake enhanced bands of heavy rainfall is expected=20 throughout the period and may lead to isolated areas of flash=20 flooding downwind along the immediate coastline.=20 Campbell Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9hiHntMzoHx2pcHTjokrwRwTGmYF5PGppvknBGH_3ZeA= CoB5n-iB_MCcZWavqXOWmODri67xxAXSltuNxj8CHxanbkQ$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9hiHntMzoHx2pcHTjokrwRwTGmYF5PGppvknBGH_3ZeA= CoB5n-iB_MCcZWavqXOWmODri67xxAXSltuNxj8Cr4HI6k4$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9hiHntMzoHx2pcHTjokrwRwTGmYF5PGppvknBGH_3ZeA= CoB5n-iB_MCcZWavqXOWmODri67xxAXSltuNxj8CDqRRzM0$=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .