Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jun 03 2025 18:54:41 FOUS30 KWBC 031854 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 254 PM EDT Tue Jun 3 2025 Day 1 Valid 1846Z Tue Jun 03 2025 - 12Z Wed Jun 04 2025 ....THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF SOUTHEAST KANSAS... ....19Z Special Update... A Moderate Risk upgrade was introduced with this update for portions of southeastern Kansas. A training line of heavy thunderstorms has set up along and south of I-35 in and east of Wichita is producing areas of considerable flash flooding. Rates in the convection currently are over 2 inches per hour, and showing no signs of weakening. The line of storms is nearly stationary, with=20 additional convection forming southwest of the area which are=20 likely to train over these same areas over the next several hours.=20 Localized totals of 7 inches have already fallen in the hardest hit areas. It's likely some areas will exceed 10 inches of rain before the line eventually moves off to the east. Additional significant flash flooding, including Flash Flood Emergencies, are likely over the next several hours. Please see MPD 351 at wpc.ncep.noaa.gov/metwatch/metwatch_mpd_multi.php?md=3D0351&yr=3D2025 for additional details. Wegman Day 2 Valid 12Z Wed Jun 04 2025 - 12Z Thu Jun 05 2025 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE UPPER MIDWEST, MIDDLE MISSISSIPPI VALLEY, SOUTHERN PLAINS, THE FOUR CORNERS, AND THE SOUTHEAST COAST... ....Four Corners into Central/Southern High Plains... Another active day of showers and thunderstorms expected as the upper low over northern Baja fills and ejects northeast atop the Four Corners. The accompanying ascent will move into continued anomalous PWs which will exceed the 99th percentile (per NAEFS). This will fuel widespread convection capable of localized rainfall rates of 0.5"/hr (or at times higher). Storms will likely move slowly beneath the upper trough, leading to a longer duration of heavy rain. Although total rainfall will be modest in most areas (as reflected by relatively low 24-hr probability from ECENS/GEFS for 1" exceedance), where the heavy rain impacts sensitive terrain features or urban areas instances of flash flooding could result. Probabilities have also increased a bit (particularly from the new 00z ECENS suite) further east into the Central/Southern High Plains and the MRGL risk has been expanded accordingly. Should models come into better agreement, additional expansion may be needed further south into West TX (and with additional CAM guidance and agreement, an upgrade to SLGT may also be needed). ....Southern Plains and Mid-Mississippi Valley to Great Lakes... The cold front from D1 will continue its trek eastward on Wednesday, but will start to slow and become aligned more west to east as its tail gets pulled northward by an approaching shortwave over the Four Corners region. Shortwaves embedded within the flow will continue to race northeast, especially from Missouri to Michigan, which is where the greatest concentration of thunderstorms is expected on D2 (though some models are also indicated potential for isolated convective development farther southwest into portions of the Southern Plains). Storm motions along the front are likely to be progressive, lifting off to the northeast on 0-6km mean winds of 20-30 kts, but weaker Corfidi vectors aligned both to this mean wind and the front suggests a potential for training. As rainfall rates peak above 1"/hr within favorable thermodynamics, this could result in stripes of heavy rainfall with ensembles indicating 10-40% chance of exceeding 1" and up to 10% probabilities for exceeding 2" (with the new ECENS being the most aggressive). The inherited MRGL risk was maintained (and expanded a bit southwest) with this update. ....Southeast Coast... Guidance continues to be somewhat aggressive with a wave of low pressure potentially developing along an inverted trough shifting northeast along the FL/GA/SC coasts. While NHC continues to indicate a 10% probability of tropical or sub-tropical development with this feature, regardless of whether a circulation forms or not, there continues to be increasing confidence that heavy rain will spread across the FL Peninsula and then rotate onshore the GA/SC coasts on Wednesday. There also has been a clear model trend of potential increased convective development farther inland to the FL Panhandle and into southeast AL and southwest GA (likely due to a stronger closed low and the associated dynamics), so the MRGL was expanded to reflect this. With PWs progged to exceed 2", above the 90th percentile, supported by warm cloud depths that may exceed 15,000 ft, efficient rainfall rates of 1-2"/hr will be likely in any showers/thunderstorms. It certainly remains possible that the heaviest rainfall in association with the potential surface low will remain just offshore, but impressive moisture convergence from Jacksonville, FL to Charleston, SC should support waves of heavy rainfall regardless of development of this system. Additionally, plentiful tropical moisture across the rest of the FL Peninsula and a shortwave continuing to pivot across the Gulf could enhance rainfall over much of Florida Wednesday, and the MRGL was maintained accordingly (with the exception of the FL Keys, which were removed due to model consensus that convection will be pulling away northward by 12z Weds). Churchill/Weiss Day 3 Valid 12Z Thu Jun 05 2025 - 12Z Fri Jun 06 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF SOUTHERN KANSAS AND NORTHERN OKLAHOMA... ....Central/Southern Plains into the Midwest... Modest return flow from the Gulf overnight on D2 looks to result in elevated PWs once again into the Southern Plains by D3, as DPVA in association with the aforementioned upper-low (now shortwave) may help to spur more significant convective organization and growth. While models are still in rather substantial disagreement on the scale of organization and ultimate placement of higher QPF amounts, there's enough agreement to reintroduce a SLGT to portions of KS/OK (where ECENS best overlaps the stronger GEFS signal). Downscaled GFS and ECMWF solutions suggest the potential for localized 2-3" totals (as do the respective ensemble exceedance probs). ....Southeast/Southern Mid-Atlantic Coast... Guidance continues to indicate the potential for further development of the aforementioned wave of low pressure. Regardless of any tropical or sub-tropical development of this feature, heavy rainfall is likely to remain in close proximity to the coast into D3. The MRGL was expanded a bit to cover the range of solutions from the models at this juncture. Churchill Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_UAe9dx8cR-946MorpedZBOkRc6KTO7CN5dkeZJRtcp_= oimsOJC4ePVEekmjeH00qamdbQLTc5IEAkur5BuI_7uMbuQ$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_UAe9dx8cR-946MorpedZBOkRc6KTO7CN5dkeZJRtcp_= oimsOJC4ePVEekmjeH00qamdbQLTc5IEAkur5BuI1716aKg$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_UAe9dx8cR-946MorpedZBOkRc6KTO7CN5dkeZJRtcp_= oimsOJC4ePVEekmjeH00qamdbQLTc5IEAkur5BuI_ij-Fa0$=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) .