Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Sat Aug 24 2024 Valid 12Z Sat Aug 24 2024 - 12Z Mon Aug 26 2024 ...Monsoonal thunderstorms across the Four Corners this weekend will edge east toward southern Rockies by early next week producing locally excessive rainfall... ...Record heat relents over the Southern Plains as record cool temperatures envelop California to the Great Basin... ...Critical Fire Risk and Red Flag Warnings in effect across much of the Great Basin... An anomalously amplified weather pattern across North America will continue to bring sharply contrasting weather conditions across the U.S. for the next couple of days. This weather pattern will feature a warm upper high over the southern Plains sandwiched in between two deep and cold upper lows/troughs on either side of the West and East Coasts. An unstable channel of moist southwesterly flow between the ridge and the upper low near the Pacific Northwest will continue to support monsoonal showers and embedded thunderstorms across the Four Corners region today, shifting only slightly east toward the southern Rockies by Monday when the flash flooding threat dwindles further as the upper high begins to give way to the upper low moving inland across the western U.S. Farther north across the northern High Plains, a couple of new low pressure systems are forecast to form one after another and move toward southern Canada through the next couple of days, bringing gusty winds but only modest amounts of rainfall. Some of the thunderstorms could become severe near the Canadian border of Montana early this morning ahead of the first low pressure system. Meanwhile, critical fire weather danger is forecast for the Great Basin under blustery and dry conditions behind a cold front. The large upper low dipping into the Pacific Northwest will continue to provide very cool and damp conditions into the West Coast today. In fact, record cool high temperatures can be found once again today across California and into the Great Basin. The anomalous cool conditions will penetrate farther inland and overspread much of the western U.S. by Sunday. In contrast, the heatwave across the southern Plains is showing signs of relenting as the cool air from the western U.S. begins to erode the upper ridge. Nevertheless, another afternoon with triple digit high temperatures are forecast for today over a large portions of Texas into the central Plains behind a warm front and associated low pressure center. With relatively little moisture to work with, the low pressure system will produce generally light amounts of rain. However, some heavy rainfall can be expected to associate with localized clusters of strong thunderstorms across the Midwest this weekend. Meanwhile, cool mornings, increasingly warm afternoons and abundant sunshine will prevail across much of the eastern U.S. under a cool upper trough together with a cool high pressure system at the surface. A gradual warming trend will continue across the eastern half of the country through the next couple of days as the high pressure system begins to slide off the East Coast. Afternoon high temperatures will recover to the lower 90s by Sunday afternoon for some urban locations along the East Coast. Meanwhile, high temperatures well into the 90s will be common across the northern and central Plains ahead of a warm front lifting across the mid-section of the country and ahead of a cold front in advance of the cool air over the western U.S. Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php