US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 436 PM EDT Mon Jul 29 2019 Valid Thursday August 01 2019 - Monday August 05 2019 Hazards: - Heavy rain across portions of the Southeast, the Southern Appalachians, the Mid-Atlantic, and the Central Appalachians, Thu-Fri, Aug 1-Aug 2. - Heavy rain across southern Florida, Thu-Sun, Aug 1-Aug 4. - Heavy rain across portions of the central Plains into the Middle Mississippi Valley, Sat, Aug 3. - Heavy rain across portions of the central and southern Rockies as well as the central and southern Plains, Sun-Mon, Aug 4-Aug 5. - Heavy rain across portions of the central High Plains, as well as over the interior Southeast, the Mid-Atlantic, and the Southern Appalachians, Mon, Aug 5. - Flooding occurring or imminent across portions of the Lower Mississippi Valley and the Northern Plains. - Flooding likely across portions of the Northern Plains. - High significant wave heights for portions of the Arctic Coast of Alaska, Thu-Fri, Aug 1-Aug 2. - High winds across portions of the Arctic Coast of Alaska, Fri, Aug 2. - High winds across portions of western Alaska, Sat, Aug 3. - Heavy rain across portions of northwestern Alaska, Sat-Sun, Aug 3-Aug 4. Detailed Summary: A number of areas in the contiguous U.S. could be impacted by heavy rain during the medium range period (Thursday, August 1 through Monday, August 5). A cold front is forecast to become stationary across the Mid-Atlantic during the weekend and into early next week. Precipitation associated with the front could be heavy over the Mid-Atlantic Thursday into Friday. Showers and thunderstorms should become more scattered during the weekend before the next batch of moisture arrives from the west by next Monday. This batch of moisture appears to be re-invigorated from the remnants of mesoscale convective system(s) (MCSs) moving across the central Plains during the weekend, which could result in areas of heavy rain across North Carolina by next Monday. The aforementioned MCS(s) forecast for the weekend over the central Plains is associated with the western extension of the stationary front across the Mid-Atlantic. A good chance of heavy rain is indicated for portions of the central Plains into the Mid-Mississippi Valley on Saturday. Farther west, monsoonal moisture interacting with a lee trough or low pressure center could lead to areas of heavy rain from the eastern slopes of the Rockies to the Front Range and into the central High Plains on Sunday and into Monday. Over southern Florida, moisture associated with a tropical wave is forecast to merge with a dissipating stationary front to result in heavy rainfall. The rain may become more widespread during the weekend as the tropical wave approaches from the Bahamas. While the daily rainfall does not appear to be particularly heavy for Florida standards, the rain is expected to last through the medium-range period. For Alaska, a frontal system ahead of an occluded cyclone is expected to spread strong winds across much of the west coast of mainland Alaska on Saturday. The rain associated with the cold front is expected to bring heavy rain especially for the south-facing mountains in northwestern Alaska. Prior to the arrival of this occluded cyclone, the Arctic Coast of Alaska will likely see strong winds and significant waves on the back-side of another occluded cyclone this Thursday into Friday. Over in Hawaii, a pair of tropical storms, Erick and Flossie, are looming across the eastern Pacific. The latest forecast from the National Hurricane Center indicates that Erick will pass at some distance south of Hawaii as a weakening tropical storm from Friday into Saturday. Possible effects for Hawaii could be some increase in northeasterly winds along with more frequent showers and increasing swells, particularly for the Big Island. On the other hand, models indicate that Flossie could move much closer toward Hawaii by early next week. Thus, the future intensity and track of Flossie need to be monitored closely. Kong