Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 432 AM EDT Wed Jul 29 2015 Valid 12Z Wed Jul 29 2015 - 12Z Fri Jul 31 2015 ...Hot and humid weather to continue over areas of the southern U.S. ...Flash flooding possible over areas of New Mexico and the Texas/Oklahoma panhandles through Thursday morning... ...Above normal temperatures to prevail across the western U.S... The upper pattern across the country will feature a broad ridge extending from the Southern Plains toward the Deep South. To the north, a high amplitude and progressive jet structure will help carve a trough over eastern Canada toward the end of the week. Meanwhile, ridging will begin to extend over a vast majority of the western states supporting above normal temperatures. Underneath the aforementioned ridge across the southern sector of the U.S., hot and humid conditions will continue. Local forecast offices have placed an expansive region from eastern Oklahoma across the Lower Mississippi valley and into the Mid/Deep South in heat advisories and excessive heat warnings. Expect heat indices to locally exceed 105 degrees in some of the previously mentioned areas. To the west of this ridge, a series of mid-level disturbances will track through the Desert Southwest and Four Corners region. These features combined with sufficient moisture and diurnal heating will support a broad area of convection. In particular, a more focused area of thunderstorms moving through northeastern New Mexico this evening may cause rainfall heavy enough to produce flash flooding. This threat will gradually shift eastward toward the Texas/Oklahoma panhandles into the overnight hours. The other region of active weather will be along and ahead of a rather pronounced cold front currently sweeping through the Upper Great Lakes. While the boundary should weaken in time as the better upper support lifts into Canada, expect showers and thunderstorms to accompany frontal passage. It appears this will occur by around Thursday evening along the I-95 corridor. Overall, the heaviest rainfall looks to be along the eastern Gulf Coast where a mid-level impulse is expected to sink southward from the Lower Tennessee valley toward the Gulf Coast. WPC is currently highlighting a broad area of 1 to 2 inches of precipitation over this area through Friday morning. Elsewhere, a building ridge along the West Coast will maintain hot conditions through at least Friday. Temperature anomalies of 10 to 15 degrees above normal will support highs reaching the century mark. In fact, temperatures should hit the 105 to 110 degree range over the interior valley locales of California and Oregon on Thursday. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php