Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Mon May 23 2016 Valid 00Z Tue May 24 2016 - 00Z Thu May 26 2016 ...Threat of severe weather and flash flooding will continue across the Plains and the Mississippi Valley... ...Unsettled weather continues throughout the western U.S... A large, slow moving upper level low over the western U.S. will continue to influence the weather throughout the western and central portions of the country over the next few days. Looking toward the western half of the country, the axis of the upper level low will slowly shift to the south and east over the Great Basin and West Coast through today and Tuesday. This will bring unsettled weather conditions especially in the Great Basin where showers and isolated thunderstorms will develop across this region. Heavier rainfall amounts can be expected on the higher terrain. Precipitation will ramp up on Wednesday throughout the Great Basin as the base of the low moves across southern California and toward the Four Corners. The aforementioned upper level low will also be the driving force over the convection across the Plains and the Mississippi Valley through the short term period. As the upper level low slowly progresses eastward, strong southerly flow will carry copious amounts of moisture from the Gulf of Mexico over the Plains. In addition, there is also plenty of instability on tap. These two ingredients, along with a very slow progressing surface front, will continue to set off thunderstorms especially on Monday and into Tuesday. To the north, the cold front will stall out by late Monday and Tuesday along the north and central Plains. This will act as the focal point for igniting convection and will bring threats of both severe weather and flash flooding on Tuesday, especially along the central Plains and middle Mississippi Valley. Farther south, most of the convection will be influenced by the forcing from the dryline in addition to diurnal heating. That particular round of activity will also have potential for severe weather. However, isolated pockets of heavy rain leading to flash flooding is also not out of the question. By Wednesday, the bulk of the precipitation shifts to the north across the upper Mississippi Valley and the Great Lakes region. Scattered thunderstorms across West Texas can also be expected once again along the dryline. Farther east in the Mid-Atlantic and Northeast, a surface low tracking north along the Northeast coast on Monday will continue to bring precipitation across these regions. On Monday night and into Tuesday morning, showers and thunderstorms will move across the Mid-Atlantic and Northeast. As the surface low moves toward New England, the precipitation activity shifts north across the Northeast and New England, with most showers tapering off in the Mid-Atlantic. By Wednesday, dry conditions settle across these regions along with above average temperatures. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php