BBS: TELESC.NET.BR Assunto: HVYRAIN: Excessive Rainfall Discussion De: COD Weather Processor Data: Sun, 31 May 2026 08:25:11 +0000 ----------------------------------------------------------- FOUS30 KWBC 310825 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 425 AM EDT Sun May 31 2026 Day 1 Valid 12Z Sun May 31 2026 - 12Z Mon Jun 01 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE NORTHERN ROCKIES AND THE SOUTHEAST UNITED STATES... Northern Rockies... With rainfall on-going from Saturday due to a slow moving mid- and upper-level system over the northern Rockies...opted to keep=20 portions of Montana and nearby Wyoming and the far western Dakotas=20 in a Slight Risk area during the new Day 1 period. The expectation=20 is that rainfall intensities will not be as high as they were on=20 Saturday but the cumulative effect of an additional 1+ inch amounts on top of what has already fallen has the potential to produce=20 flooding concerns today. The Slight risk area was extended into far western South Dakota where MRMS showed 3+ inches having fallen on=20 Saturday evening and was susceptible to flooding from even modest=20 rainfall amounts. Southeast US... Also introduced a Slight Risk area over portions of the Southeast US where some model agreement has developed...although the agreement was far from unanimous. Neither the HREF or RRFS showed=20 a strong signal for exceedance of flash flood guidance but showed=20 about 20 percent neighborhood probabilities of rainfall exceeding 2 inches. At the same time...a spaghetti plot of SREF QPF showed=20 decent amount of ARW members with QPF at 2 inch and 3 inch amounts. That was largely supported by the GEFS. Given the 2 to 2.25 inch=20 precipitable water values and the amount of instability in the area that could support intense rainfall rates...opted to include a=20 Slight Risk at this point. Elsewhere...maintained the broad and largely unfocused Marginal Risk area in between given the lack of clear forcing mechanism, the light flow aloft and the broad pool of instability along and south of a quasi-stationary boundary.=20=20 Bann Day 2 Valid 12Z Mon Jun 01 2026 - 12Z Tue Jun 02 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE NORTHERN ROCKIES AND PARTS OF THE PLAINS... Northern Rockies...=20 Introduced a Marginal Risk area in the northern Rockies where=20 moisture/precipitation lingers as a slow moving mid- and upper-=20 level system pulls away. The concern is not so much for rainfall=20 intensity at this point but for the cumulative effect of the=20 additional rain on top of what has fallen in the previous few days. The concern is also fairly limited in terms of duration as=20 rainfall does come to an end during the middle- to latter-part of=20 the period. Western High Plains... Also introduced a Marginal Risk area mainly in the western portion of Kansas/Nebraska as an axis of low level moisture begins to=20 return northward during the day. Placement of the QPF and any=20 associated risk of excessive rainfall remains somewhat tenuous.=20 Concern is that the instability should be enough that the QPF=20 amounts approaching or exceeding 2 inches from the UKMET/NAM and=20 GFS would be delivered quickly. A Southeast US... Portions of the Mid-South/Southeast may also be at-risk for=20 Excessive Rainfall, but guidance remains murky on where storms will initiate. Given these reasons, the Day 2 ERO remains free of risk=20 areas for the time being. Mullinax/Bann Day 3 Valid 12Z Tue Jun 02 2026 - 12Z Wed Jun 03 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF NEW MEXICO AND A SMALL PORTION OF WEST TEXAS... A plume of Gulf-sourced moisture will be drawn northward into the=20 southern Rockies/drifting east over the southern High Plains/west=20 Texas to maintain a Slight Risk area for excessive rainfall on Tuesday into Tuesday night from portions of New Mexico into west=20 Texas. Farther north...warm moist air will advect along a low=20 level convergence zone with early June heating that has the=20 potential for locally heavy rainfall over portions of the western High Plains into the Dakotas. Bann Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-5hgMhGXcmwogx9qw1GvsYWjfqEWvzjzCRYMvm-gVaMM= iTn_Ilt-NiNA-GKncC5W-DljKUwIbhYxciMyP_xn4g6g-qU$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-5hgMhGXcmwogx9qw1GvsYWjfqEWvzjzCRYMvm-gVaMM= iTn_Ilt-NiNA-GKncC5W-DljKUwIbhYxciMyP_xntiwh_xg$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-5hgMhGXcmwogx9qw1GvsYWjfqEWvzjzCRYMvm-gVaMM= iTn_Ilt-NiNA-GKncC5W-DljKUwIbhYxciMyP_xnjcuZ0AY$=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: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]