Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 05 2025 08:06:08 FOUS30 KWBC 050805 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 405 AM EDT Thu Jun 5 2025 Day 1 Valid 12Z Thu Jun 05 2025 - 12Z Fri Jun 06 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTH-CENTRAL PLAINS... ....Central to Southern Plains... Shortwave energy embedded in the west southwesterly mid to upper=20 level flow across the Central to Southern Plains will support=20 additional organized convection late Thursday afternoon into=20 Thursday night/early Friday morning across portions of the Central to Southern Plains. The low level southerly flow expected to=20 strengthen Thursday afternoon into the northward moving warm front=20 across the Southern Plains, igniting convection across southeast=20 Colorado, with this activity then enhancing as it treks east=20 southward across southern KS and northern OK. The previous broad=20 slight risk area was narrowed to better align with the higher HREF=20 neighborhood probabilities for 2 and 3"+ amounts and where the HREF EAS probabilities for 1"+ amounts were highest, indicating where=20 hi res guidance was in better agreement. South of this west to east slight risk area, there was less agreement on convective placement across western TX. The previous slight risk area was reduced to=20 marginal given this and higher FFG values.=20 Upstream across the Southern Great Basin into the Southern to Central Rockies...no changes made to the previous slight risk=20 area. PW values expected to remain well above average from southern NV into northern AZ, Southern UT and western CO, supporting=20 another day of widespread scattered convection, locally heavy rains and isolated runoff issues.=20 ...Lower Lakes, OH Valley into the Mid to Lower MS Valley... PW values also expected to remain above average in the vicinity of the nearly stationary frontal boundary stretching from the lower Lakes, southwest into the OH Valley and Mid to Lower MS Valley. A broad marginal risk area was maintained from previous issuances for localized heavy rainfall and isolated runoff issues. The previous marginal risk area was narrowed to better reflect latest model=20 consensus on the moderate to locally heavy qpf axis. ....Coastal SC into eastern NC... A weak surface low, accompanied by an axis of above average PW values will push northeast along the SC/NC coasts day 1. The=20 latest model consensus is for the axis of the heaviest=20 precipitation to remain offshore, indicated by fairly high HREF EAS probabilities for 1, 2 and 3"+ totals off the NC coast. Given=20 this, the previous slight risk area over the central NC coast was=20 removed. There is consensus for an inland max day 1 qpf across=20 southeast NC. The HREF neighborhood probabilities are fairly high=20 for 2 and 3"+ amounts, although there is not good overlap in=20 placement as EAS probabilities are much lower for these values.=20 Considered a slight risk here, but with FFG values high and low EAS probabilities for the 2 and 3"+ amounts, the risk was kept at=20 marginal. Oravec Day 2 Valid 12Z Fri Jun 06 2025 - 12Z Sat Jun 07 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF OKLAHOMA INTO THE KANSAS, OKLAHOMA, MISSOURI, ARKANSAS BORDER=20 REGION... ....Oklahoma into the OK/KS/MO/Ar border area...=20 Another round of shortwave energy forecast to drop east=20 southeastward from the Central Rockies into the Central to Southern Plains Friday into Friday night/early Saturday. This will support=20 potential for another round of organized convection in the vicinity of the west to east oriented frontal zone. PW values along this=20 front will remain above average...2+ standard deviations above the=20 mean, supporting heavy precip potential. There is fairly good=20 model consensus for an axis of heavy rains along this front across=20 much of OK into the OK/KS/MO/AR border region. Only some slight=20 changes to the previous slight risk area to reflect this qpf axis=20 consensus. ....Southern Great Basin into the Central to Southern Rockies...=20 Not a lot of changes expected to the large scale flow from day 1=20 across the southern Great Basin into the Central Rockies. PW values forecast to remain above average with additional shortwave energy=20 moving across the region in the west south west flow aloft. This=20 should support another day of widespread scattered convection and=20 localized heavy rain and isolated runoff issues. The marginal risk=20 was extended back across these areas to be more similar to the day=20 1 period given the similar overall conditions day 2. ....Mid MS Valley, OH Valley into New England... Similar to the day 1 period, an axis of above average PW values=20 will stretch along the slow moving front stretching from the Mid MS Valley, OH Valley into New England. There is good model consensus=20 on a broad region of moderate to locally heavy precip amounts along this front. Only some minor changes to reflect the latest model=20 qpf axis consensus made to the previous broad marginal risk area=20 across these regions. Oravec Day 3 Valid 12Z Sat Jun 07 2025 - 12Z Sun Jun 08 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS THE LOWER ARKANSAS VALLEY, LOWER MISSISSIPPI VALLEY INTO THE LOWER TENNESSEE VALLEY... The second round of height falls moving into the Central to=20 Southern Plains day 2 will continue to push east southeast toward=20 the Mid to Lower MS Valley, OH and TN Valleys. Upper difluence is=20 forecast to be well defined Saturday into Saturday night/early=20 Sunday in an axis of above average PW values that will remain along the west to east oriented frontal boundary across these areas.=20 This should support potential for another round of organized=20 convection along this front. There is some spread with the qpf=20 axes, but consensus that heavy amounts are possible along this=20 front. The previous slight risk area was expanded eastward=20 considerably from eastern OK, across much of AR, western TN and=20 northern MS.=20 ....Northern New England... A sharpening northern stream trof will push surface low pressure across northern New England on Sunday. There is fairly good model=20 consensus for moderate to locally heavy precip totals across=20 northern New England. Only some slight changes to the previous=20 marginal risk area, extending it into all of northern Maine to=20 cover the model qpf spread. Oravec Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!89dzLwMlhVOWUMxxjGcPo0W_ePUINbUdrOnfn7_-L70L= OecVrf0gWVudtgwYAkqiK3Uh7IxROZzMVowHrzFns_f3dz0$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!89dzLwMlhVOWUMxxjGcPo0W_ePUINbUdrOnfn7_-L70L= OecVrf0gWVudtgwYAkqiK3Uh7IxROZzMVowHrzFnwXidjcg$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!89dzLwMlhVOWUMxxjGcPo0W_ePUINbUdrOnfn7_-L70L= OecVrf0gWVudtgwYAkqiK3Uh7IxROZzMVowHrzFnfU-Wi8s$=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .