128 FXUS01 KWBC 162006 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Wed Sep 16 2026 Valid 00Z Thu Sep 17 2026 - 00Z Sat Sep 19 2026 ...A moderate risk of flash flooding through tonight across portions of Arizona and New Mexico... ...Showers and thunderstorms could lead to flash flooding over sections of the north-central U.S. during the next few days... ...Record-challenging high temperatures continue across the south-central U.S.... A moderate risk of flash flooding is anticipated through tonight across portions of Arizona and New Mexico. This is in response to a low to mid-level sub-tropical circulation being drawn northward across northwestern Mexico toward Arizona ahead of a large scale upper-level trough moving into the West Coast of the U.S. This circulation will lift monsoonal moisture already in place across the Four Corners region to enhance rainfall amounts especially near the moderate risk areas in central Arizona and New Mexico where upwards of 2-3" of rain with locally higher amounts are possible through tonight. By Thursday, the circulation is forecast to move northward through Arizona and the Four Corners as it weakens. The coverage and intensity of rainfall is forecast to lessen as the day progresses. However, more heavy rain may be triggered if this circulation remains stronger than expected. By Friday, the disturbance should become much diffused but widely scattered flash flooding is still a concern across the Four Corners states with additional showers and thunderstorms. Meanwhile, a meandering front will remain the focus for thunderstorms and locally heavy rainfall across the Midwest to the Ohio Valley through tonight. Meanwhile, the upper-level energy ejecting from the Four Corners heavy rain will trigger the formation of a new low-pressure system over the central High Plains by Thursday night. Expect a round of strong thunderstorms and local heavy rainfall across the Northern Plains Thursday night moving into the upper Midwest on Friday where WPC is highlighting a slight risk of flash flooding. As we get into mid-September, cooler air from Canada is beginning to dip into the northern tier states, bringing cooler than normal temperatures. Meanwhile, an upper-level high associated with the persistent heat dome remains strong across the South, resulting in a pronounced north-south temperature contrast. High temperatures in the low 70s and upper 60s can be expected north of the meandering front in the Central Plains and Midwest, compared to upper 90s and triple-digit highs south of the front across the Southern Plains and Mid/Lower Mississippi Valley. Unfortunately, the western end of the front lifting northward means that the hazardous heat is here to stay this week across the South. In fact, high temperatures reaching into the upper 90s to lower 100s will challenge daily records from the Southern Plains to the lower Mississippi Valley where Heat Advisories remain in effect. Meanwhile, instability associated with a stationary front on the southern edge of the heat dome will continue to bring scattered thunderstorms with heavy downpours across much of the Sunshine State, although excessive rainfall is not expected from this activity. Kong/Asherman Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$