Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 AM EDT Tue Aug 07 2018 Valid 12Z Tue Aug 07 2018 - 12Z Thu Aug 09 2018 ...Unsettled weather expected to shift across the south-central and eastern U.S. through the work-week... ...Excessive heat and air quality concerns will persist across portions of the West, Southwest, and Northeast... ...Red Flag Warnings continue across southern California... ...Hurricane John will track northwest near the Baja California Peninsula... A cold front will pass through the Great Lakes region and into the Northeast over the next few days while acting as a focus for scattered to widespread shower and thunderstorm develop. The trailing end of the front will slow considerably across the central U.S. Slow storm motion along this portion of the front will increase the likelihood of heavy rainfall and flash flooding risk. WPC has highlighted this region as having a marginal-to-slight risk for excessive rainfall. Additionally, the Storm Prediction Center has issued a slight risk for severe storms for portions of the Southern/Central Rockies. A ridge over the Southwest, extending northward over much of the West, will keep hot and mostly dry conditions in place for the next the few days. This is resulting in rising temperatures and excessive heat across much of this region. Excessive heat warnings are in effect for much of the Southwest and southern California. Excessive heat watches are also in effect for the Northern Great Basin. Several locations could observe daily maximum temperature reading exceeding 100 degrees. These hot and dry conditions will maintain an elevated threat for the spread of wildfires. Red Flag Warnings along with Air Quality Alerts are still in place across southern California, Nevada and Arizona. Air Quality Alerts are also in effect for parts of Washington and Oregon. An steady increase in moisture is expected for Mexico and the Desert Southwest as Hurricane John tracks north and west in the Pacific Ocean. Showers and thunderstorms may be possible for the Southwest by the end of the week. On the east coast, strong southerly flow will pump hot and humid air inland. This will result in above normal temperatures and even higher heat index values, especially across the Northeast. Heat Advisories and Air Quality alerts for excessive ozone concentrations are in effect across much of the Northeast and the northern extent of the Mid-Atlantic region through Tuesday. A cold front will pass through after this point and help to cool things down. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php