Quantitative Precipitation Forecast
Issued by NWS
Issued by NWS
568 FOUS30 KWBC 252047 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 447 PM EDT Tue Jun 25 2024 Day 1 Valid 12Z Tue Jun 25 2024 - 12Z Wed Jun 26 2024 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF MIDWEST... 16Z update... Due to ongoing severe comms issues graphics and other data are largely unable to update. For the Southwest, with the peak heating of the day showers and thunderstorms are expected to fire up across the region this afternoon and continue through the evening hours. These slow moving storms will increase the risk for localized flash flooding concerns, especially over favored sensitive terrain. For the Midwest, a west-east line of storms span from southern Iowa to northern Ohio this morning have brought moderate to heavy rain over some of the same areas from yesterday. Redevelopment is anticipated roughly between 3 and 7pm across north-central portions of the Iowa that will have the potential to produce high rainfall rates over near/over-saturated soils, thus aggravating any flooding over the area. Campbell ...Southwest... PW values will remain highly anomalous (above the 95th climatological percentile and +5 standard deviations) from southern California into the Southwest with a continuation of weak forcing under the upper ridge axis stretching from the Southern/Central Plains into the Southwest. An influx of deeper moisture throughout the mid-levels associated with a tropical disturbance over Mexico. This added moisture when combined with sufficient instability should create greater coverage in convection through the afternoon and evening hours. The sensitive urban locations in and around Tucson prompts a greater risk for scattered flash floods and runoff issues. The trend of slow- moving convection occurring across sensitive terrain is expected to persist which may lead to isolated heavy rainfall and flooding concerns across the broad region of the Southwest and Four Corners. ...Upper Mississippi Valley/Upper Great Lakes... The surface frontal boundary oriented northwest to southeast from the Northern Plains into the Mid Missouri Valley begin to push back to the northeast toward the Upper Mississippi Valley/Upper Lakes region. Strengthening south-southwesterly low level flow into this front will raise PW values to 1.5-2" along and to the northeast of the front. Shortwave energy pushing eastward across the Northern Plains toward the Upper Mississippi Valley will help strengthen isentropic lift over this front and support for overrunning convection. There is not a lot of agreement on placement of any heavy precip totals, but overall some potential given the favorable MCS set up. There is potential for heavy rains to overlap where recent heavy rains fell across southern MN/northern IA and into northern IL. Snell/Oravec Day 2 Valid 12Z Wed Jun 26 2024 - 12Z Thu Jun 27 2024 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE NEW MEXICO... ...Southwest... 21Z update... Due to ongoing severe comms issues graphics and other data are largely unable to update. The latest guidance continues to focus some of the highest QPF across central New Mexico, with amounts of 0.50 to 1 inch possible. This part of the state has a Slight risk in effect (albeit an old graphic) and that still matches the level of risk for localized flooding potential. Isolated to scattered thunderstorms are expected across the Four Corners, Southern/Central Rockies and into the Central High Plains. Guidance is suggesting areal averages of 1 to 2 inches for portions of western Nebraska and Kansas. FFG over this part of the country is a still higher than over the Southwest however these storms may have the potential for higher rainfall rates that could reach or exceed FFG in isolated locations. A Marginal Risk covers much of the Four Corners to the Central High Plains area. Campbell No significant large scale changes expected during this period over the Southwest besides the gradual northward lifting of anomalous PWs into parts of UT. PW values 3-4+ standard deviations above the mean will persist from southern California, into the Southwest and southern Great Basin in a region of continued weak forcing under the building closed high over the Southwest. Widespread scattered diurnal convection again possible across these areas, with continued low confidence in any qpf details. There is some elevated concern that convection could be widespread enough to create scattered flash flooding throughout the slot canyon region of south-central Utah. This area will likely be monitored for a targeted upgrade over the next few days should sufficient instability show up in CAMs and greater qpf coverage. ...Lower Mississippi Valley to the Northeast... 21Z update... Due to ongoing severe comms issues graphics and other data are largely unable to update. During this period showers and thunderstorms are expected to develop along and ahead of the front moving through the Great Lakes, Midwest and Mississippi Valley. With the west-east orientation of the front along with anomalous PW pooled over the region, training of thunderstorms with potential for moderate to heavy downpours can be expected across portions of the Midwest, Lower Great Lakes and into parts of the Northeast. This is where some of the highest QPF amounts are expected to focus. A Marginal Risk is in effect (albeit an old graphic) from the Lower Mississippi Valley/Central Gulf Coast to the Northeast. The continues to reflect the level of threat for excessive rainfall and flooding concerns at this time. Campbell In the wake of the warm front pressing northeastward across the Upper Mississippi Valley/Upper Lakes region, the associated cold front will be dropping southeast from the Northern Plains into the Upper Mississippi Valley/Upper Lakes during this period. Additional convection likely to develop in the axis of high PWs pooling along the front that becomes more west to east oriented. Convection may train in a west to east direction parallel to this front as the low level flow will also be westerly along and ahead of the boundary. There still is spread in model qpf details, but the multi model ensemble qpf mean and latest NBM do show potential for heavy amounts across areas of far southern WI/eastern IA and northern IL that have received heavy rainfall recently. A broad marginal risk spans from the central Gulf Coast, portions of the Tennessee/Ohio Valleys and most of the Northeast. Snell/Oravec Day 3 Valid 12Z Thu Jun 27 2024 - 12Z Fri Jun 28 2024 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS AND FOR PORTIONS OF NEW MEXICO, COLORADO AND FAR SOUTHERN WYOMING... 21Z update... Due to ongoing severe comms issues graphics and other data are largely unable to update. Moderate to heavy showers are expected in the vicinity of the Central Rockies and south to north-central New Mexico. A Slight Risk is in effect for this part of the region. Over the Plains, another area of concentration of heavy rain will be over eastern Kansas/Nebraska and much of Iowa. This part of the country has had recent rains to bring soils to near saturation. An additional 1 to 3 inches over this region may lead to areas of isolated to scattered flash flooding therefore a Slight Risk is in place. Moderate to heavy showers will also be tracking near the International border where recent rains have kept soils moisture above average. Additional rain from far northeast Montana to northwest Minnesota may lead to scattered areas of flooding, a Slight Risk remains in effect. Campbell A low pressure system and associated fronts tracking into the Northern Plains Thursday will bring a threat for heavy rainfall across the north-central Plains into the Upper Midwest. Some conflicting signals remain regarding locations that may see significant rainfall, but latest guidance is suggesting two areas of relatively greater focus during the period. One is within the existing Slight Risk area over parts of the Midwest with a modest southwestward adjustment per latest guidance, and another farther north across northern North Dakota and far northwestern Minnesota where a Slight Risk area has been introduced. Slight Risk areas within the broader Marginal Risk are subject to change based on updated forecasts of convective evolution and location relative to areas with greatest sensitivity due to prior heavy rainfall. Santorelli 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