US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 352 PM EDT Fri Jul 05 2019 Valid Monday July 08 2019 - Friday July 12 2019 Hazards: - Heavy rain across portions of the Central Plains, the Northern Plains, the Middle Mississippi Valley, the Mid-Atlantic, the Upper Mississippi Valley, and the Southeast, Mon-Tue, Jul 8-Jul 9. - Heavy rain across portions of the Southeast and the Lower Mississippi Valley, Tue-Fri, Jul 9-Jul 12. - Heavy rain across portions of the Mid-Atlantic, the Northeast, and the Great Lakes, Thu, Jul 11. - Severe weather across portions of the Northern Plains, Mon, Jul 8. - Flooding possible across portions of the Central Plains and the Northern Plains. - Flooding occurring or imminent across portions of the Central Plains, the Middle Mississippi Valley, the Lower Mississippi Valley, and the Ohio Valley. - Flooding likely across portions of the Central Plains, the Middle Mississippi Valley, the Upper Mississippi Valley, and the Northern Plains. - Excessive heat across portions of the Southeast, the Lower Mississippi Valley, the Southern Plains, and the Tennessee Valley, Mon-Thu, Jul 8-Jul 11. - Excessive heat across portions of the Central Plains, the Middle Mississippi Valley, the Lower Mississippi Valley, and the Southern Plains, Tue-Wed, Jul 9-Jul 10. - Enhanced wildfire risk across portions of the mainland Alaska, Mon-Fri, Jul 8-Jul 12. - Much above normal temperatures across portions of mainland Alaska, Mon-Fri, Jul 8-Jul 12. Detailed Summary: Progressive flow will prevail across the northern states, while a sprawling upper ridge generally encompasses much of the central and southern two thirds of the CONUS through much of next week. A short wave trough and associated surface cold front will move steadily eastward from the northern high Plains Monday through the Great Lakes region Wednesday, then into the Northeast by the end of the week. Strong convergence along the front, along with favorable upper dynamics will support widespread and potentially severe convection across the northern Plains and northern Mississippi Valley Monday-Tuesday, with rainfall amounts ranging from about 1-2 inches each day. Rainfall along this cold front will tend to be lighter and more scattered as it moves through the Great Lakes states Wednesday, but with the upper trough amplifying in the Northeast and tapping some deep Atlantic moisture, expect widespread heavier rains through the northern Mid-Atlantic states into New England during Thursday. There is some uncertainty among the guidance with the speed of this front, so confidence in the timing of the rainfall in the Northeast is lower than average. Farther south, diffluent flow along the southern edge of the westerlies will combine with Gulf moisture overrunning a warm frontal boundary to support a series of organized convective systems crossing the central Plains and middle Mississippi Valley during Monday and Tuesday. Rainfall amounts will generally range from 1-3 inches over the two days, but with model guidance showing a fair amount of disagreement with the timing and placement of the heaviest precipitation, overall confidence with this hazard area is low. Over the southeastern U.S. and eastern Gulf Coast region, a stalled-out surface front will be the focus for daily periods of showers and thunderstorms through a good part of next week. Across the eastern Carolinas and eastern Georgia, convergence along the boundary looks to be the strongest Monday-Tuesday, then there may be somewhat reduced activity as a short wave ridge builds in Wednesday. By Thursday-Friday, rainfall looks to become a bit more widespread as the cold front associated with the short wave moving into the Northeast reinforces the moisture convergence along the existing stalled boundary. Across the eastern Gulf Coast, a mesoscale convective vortex currently over Missouri is expected to drop southeastward and perhaps spin up a low near the Florida Panhandle in the vicinity of the abovementioned stalled front. This low then may drift slowly westward toward the central Gulf Coast during the latter part of next week. With plenty of deep moisture and instability present, expect daily rounds of slow-moving, heavy convection which could result in localized flash flooding. Over the southern Plains and lower-mid Mississippi Valleys, the combination of high temperature in the 90s and dew points in the middle 70s will result in heat indices approaching 105-110 next week. The most prolonged period of high heat indices (Monday through Thursday) will extend from eastern Oklahoma and northeastern Texas across Arkansas and northern Louisiana into northern and central Mississippi. During Tuesday and Wednesday, the excessive heat will expand across much of Oklahoma, southeastern Kansas, and southwestern Missouri. However, by the end of the week, the heat wave should break as a cool front pushes through this entire region. Persistent ridging in Alaska will remain through the middle of next week, after which it looks like it will finally begin to weaken. Much above average temperatures as well as an enhanced risk of wildfires are expected to continue across much of the central and southern portions of mainland Alaska through the period, with the warmest weather and continued record-setting temperatures likely Monday and Tuesday. Temperatures will begin to moderate later in the week, especially over southwestern and eastern sections of the mainland. Current Hurricane Barbara is expected to weaken over the next few days and become post-tropical as it moves westward toward Hawaii. Hawaii may see some effects of the system Monday and Tuesday before Barbara dissipates, with high surf, locally heavy rain, and gusty winds. Klein