Forecast Discussion
— ExtendedOverview
An upper-level ridge centered over the Southeast will retrograde into the Southern Plains and eventually the West next week. This ridge will be responsible for hazardous heat for the South-central U.S.. Rounds of shortwave energy propagating through the North-central U.S. will fuel severe weather and excessive rainfall concerns across portions of the Upper Midwest/Great Lakes early next week.
Guidance/Predictability Assessment
Models are in good agreement on the evolution of the Southern ridge, while more uncertainty exists regarding the evolution of a Northwestern trough. Ai models diverge from consensus with respect to the troughs propagating through the Northwest as the Ai models attempt to split flow, while the rest of the models keep a more phased solution.
A general model blend consisting of the available deterministic and Ai guidance is used on days 3-5. The Ai models are removed from the blend on days 6 and 7 and replaced with a more ensemble mean favored blend due to uncertainties on the timing and amplitude of the West Coast trough.
Weather/Hazards Highlights
A system moving through the Central U.S. will stall one of its attendant fronts over the Great Plains, Upper Midwest and Great Lakes next week. This will lead to a multi-day heavy rain threat with the potential for excessive rainfall leading to flash flooding to develop. This threat is expected to begin over the Upper Midwest/Great Lakes on Monday along with some severe weather potential extending from the Central Plains to the Middle Mississippi Valley. The excessive rainfall threat redevelops over the Central Plains into the Middle/Upper Mississippi Valley on Tuesday and continues through Wednesday.
A ridge over the South will generate above average temperatures across the Central/Southern Plains and into the Lower Mississippi Valley next week. Heat indices between 100-110 degrees may support excessive heat risk over portions of the aforementioned areas between Monday and Wednesday.
The return of the Central U.S. ridge should reinvigorate monsoonal storms across the Southwest beginning early next week. Moist southerly flow into the Southwest could produce isolated instances of flash flooding across portions of eastern Arizona through much of New Mexico. Burn scars, dry washes and slot canyons are especially sensitive to any heavy rainfall that occurs.
Kebede
Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at:
000 FXUS02 KWBC 110813 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 413 AM EDT Fri Sep 11 2026 Valid 12Z Mon Sep 14 2026 - 12Z Fri Sep 18 2026 ...Hazardous heat over the Southern Plains as heavy rain and severe weather threats emerge across the Upper Midwest/Great Lakes early next week... ...Overview... An upper-level ridge centered over the Southeast will retrograde into the Southern Plains and eventually the West next week. This ridge will be responsible for hazardous heat for the South-central U.S.. Rounds of shortwave energy propagating through the North-central U.S. will fuel severe weather and excessive rainfall concerns across portions of the Upper Midwest/Great Lakes early next week. ...Guidance/Predictability Assessment... Models are in good agreement on the evolution of the Southern ridge, while more uncertainty exists regarding the evolution of a Northwestern trough. Ai models diverge from consensus with respect to the troughs propagating through the Northwest as the Ai models attempt to split flow, while the rest of the models keep a more phased solution. A general model blend consisting of the available deterministic and Ai guidance is used on days 3-5. The Ai models are removed from the blend on days 6 and 7 and replaced with a more ensemble mean favored blend due to uncertainties on the timing and amplitude of the West Coast trough. ...Weather/Hazards Highlights... A system moving through the Central U.S. will stall one of its attendant fronts over the Great Plains, Upper Midwest and Great Lakes next week. This will lead to a multi-day heavy rain threat with the potential for excessive rainfall leading to flash flooding to develop. This threat is expected to begin over the Upper Midwest/Great Lakes on Monday along with some severe weather potential extending from the Central Plains to the Middle Mississippi Valley. The excessive rainfall threat redevelops over the Central Plains into the Middle/Upper Mississippi Valley on Tuesday and continues through Wednesday. A ridge over the South will generate above average temperatures across the Central/Southern Plains and into the Lower Mississippi Valley next week. Heat indices between 100-110 degrees may support excessive heat risk over portions of the aforementioned areas between Monday and Wednesday. The return of the Central U.S. ridge should reinvigorate monsoonal storms across the Southwest beginning early next week. Moist southerly flow into the Southwest could produce isolated instances of flash flooding across portions of eastern Arizona through much of New Mexico. Burn scars, dry washes and slot canyons are especially sensitive to any heavy rainfall that occurs. Kebede Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$