FOUS30 KWBC 120808 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 408 AM EDT Fri Jun 12 2026 Day 1 Valid 12Z Fri Jun 12 2026 - 12Z Sat Jun 13 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE SOUTHERN ROCKIES THROUGH THE MID-SOUTH, MID-ATLANTIC, AND NORTHEAST AS WELL AS FOR CENTRAL AND SOUTHWEST FLORIDA... ...South-Central States through Northeast... An upper trough over Michigan early this morning will shift east across the Northeast through tonight. Prefrontal activity ahead of the associated cold front persists over Lake Erie and the lower Ohio Valley with stronger activity over the Oklahoma/Arkansas border early this morning. Deep moist convection develops diurnally today ahead of the cold front east of the Mid-South and a warm front lifting over the southern Plains. An extensive Marginal Risk remains from the southern Rockies/Sacramento and Davis Mtns across Texas/Oklahoma, the Mid-South/Tennessee Valley and over New England. Some activity is still progged over the Central Appalachians, so the Marginal Risk was maintained there, though it is a notably low risk compared to northern New England and the Tennessee Valley where PW anomalies are over 2 sigma (more like a peak of 1.5 sigma in the Mid-Atlantic). Most of this activity will be fairly progressive hence no Slight Risks at this time. Some trimming of the north side to the Marginal Risk was made, though timing tonight with surging Gulf moisture limits that reduction, particularly based on the 06Z HRRR with central Missouri activity late tonight. ...Central and Southwest Florida... Anomalous moisture will reside over southwest and central portions of the Florida Peninsula today, though it should be a little less in terms of PW compared to Thursday. Convection along the sea breezes should produce very heavy rainfall that could lead to flooding concerns for urban areas in Central and Southwest Florida. A Marginal Risk remains in effect with Tampa Bay removed due to CAM consensus to the east/south of there. Jackson Day 2 Valid 12Z Sat Jun 13 2026 - 12Z Sun Jun 14 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE CENTRAL PLAINS THROUGH THE MIDDLE MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY... An upper trough swings down the northern Plains Saturday, pushing a cold front across the central Plains and Midwest through Saturday night. Meanwhile, a warm front tracks from Oklahoma through Illinois ahead of the cold front, creating focus for strong convergence in a very warm, moist, and unstable air mass. Resultant heavy thunderstorms look to organize and repeat from the central Kansas/Oklahoma border through central/southern Illinois and western Kentucky where the Slight Risk was expanded a bit. Particular focus for heavy rain remains near the Kansas/Missouri border where a higher than normal Slight Risk is noted. Scattered instances of flash flooding can be expected and a targeted Moderate Risk is possible. More isolated heavy thunderstorms are also expected over the eastern New Mexico and west Texas terrain and nearby plains where the Marginal Risk remains. The Marginal Risk was removed from most of Michigan based on the 00Z high-res solutions available with little PW anomaly noted. Jackson Day 3 Valid 12Z Sun Jun 14 2026 - 12Z Mon Jun 15 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF TEXAS AND THE LOWER MISSISSIPPI VALLEY... ...Southern Rockies, Texas to Southeast... A cold front pushes down the Southern Plains into Texas on Sunday. This shunts the heavy rain focus south of Saturday and provides a strong focus for convective development in a rich Gulf-sourced moisture environment. PW anomalies are 2 to 3 sigma above normal across Texas (south of the Panhandle) by that afternoon with 2 sigma anomalies expanding east to Alabama by late Sunday night. Expansion of the Slight Risk to both North Texas and the Houston metro areas are warranted given the environment as well as the 00Z consensus of the UKMET and EC-AIFS for the Houston area, and the RRFS and RDPS for North Texas. Furthermore, a decent signal for lasting thunderstorm development is over West Texas in the Permian Basin into the Concho Valley, so a Slight Risk was raised there as well. Additional terrain driven diurnal activity is expected over the Southern Rockies/Sacramento and Davis Mtns. This activity should spread southeast through the evening, so the Marginal Risk was expanded over the southern High Plains. A surge of moisture up the southern Appalachians Sunday morning brings enough of a heavy rain threat for a Marginal Risk expansion up to the westernmost section of Virgina. ...Hampton Roads and Delmarva... Southwesterly low level flow from the Carolinas bring 2" PW to the Mid- Atlantic coast Sunday afternoon ahead of a cold frontal passage that night. Evening thunderstorms should be heavy and slow enough to warrant a Marginal Risk. Jackson Day 4 and Day 5 Valid 12Z Mon Jun 15 2026 - 12Z Wed Jun 17 2026 ...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AND THE SOUTHEAST... Overall, not much change from the previous forecast, with the overnight guidance continuing to present a good signal for highly- efficient training storms along a slow-moving front settling into the region. Models continue to show a cold front settling slowly south though the southern Plains, lower Mississippi Valley, and the Southeast as shortwave energy gradually amplifies a broad upper trough centered along the Mississippi Valley on Monday. A deepening pool of moisture along the front, fed by southerly low level inflow from the western Gulf, will fuel the potential for highly-efficient showers and storms. Guidance continues to show PWs increasing to 2.25 inches (2.5 to 3 std dev above normal) along and ahead the front from south South Texas to southern Alabama on Monday. Interacting with this moisture is expected to be an area of enhanced ascent provided by right-entrance region upper jet forcing positioned along the base of the amplifying trough. In addition to the deep moisture and large-scale ascent, repeating storms are expected to raise the potential for heavy amounts and flash flooding concerns. A Slight Risk was maintained from southeastern Texas to central and southern Alabama on Day 4. By Tuesday, the upper trough axis begins to shift to the east, pushing the front, deeper moisture, and the better chance for heavy rain farther south and east along the Gulf Coast. For Day 5, a Slight Risk was drawn from southeatern Lousiana to southwestern Georgia. While Slight Risks were drawn for both periods, given the potential for several inches of rain in some locations, an upgrade to a Moderate Risk may be required in future updates if the signal persists as the event draws nearer. Pereira Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt $$