US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 517 PM EDT Fri Jul 02 2021 Valid Monday July 05 2021 - Friday July 09 2021 Hazards: - Heavy rain across portions of central and southern Texas and southwestern Louisiana, Mon-Thu, Jul 5-Jul 8. - Heavy rain across portions of the Mid-Missouri Valley and the Upper Mississippi Valley, Tue, Jul 6. - Heavy rain across portions of the Southeast and the Carolinas, Tue-Wed, Jul 6-Jul 7. - Flooding possible across portions of the Central Plains and the Middle Mississippi Valley. - Flooding occurring or imminent across portions of the Central and Southern Plains, the Great Lakes, and the Middle Mississippi Valley. - Flooding likely across portions of the Central and Southern Plains and the Middle Mississippi Valley. - High winds across portions of the Southeast, Tue-Wed, Jul 6-Jul 7. - Much above normal temperatures across portions of the Interior Northwest, the northern Great Basin, and the Northern Rockies, Mon-Fri, Jul 5-Jul 9. - Much above normal temperatures across portions of the Northern High Plains, Wed-Thu, Jul 7-Jul 8. - Much below normal temperatures across portions of mainland Alaska, Mon-Thu, Jul 5-Jul 8. Detailed Summary: There are several hazards outlook areas forecast for the medium-range period (Monday, July 5 - Friday, July 9), highlighted by the potential impacts associated with Hurricane Elsa. There is still a great deal of uncertainty in both the deterministic and ensemble model guidance on both the track and intensity of Elsa, so a broad area of heavy rain and high winds was included for Tuesday, July 6th and Wednesday, July 7th. The National Hurricane Center official forecast track brings Elsa northward up towards the west coast of Florida on Tuesday morning before turning north-northeastward and making landfall as a tropical storm. High winds associated with the storm are expected from the Florida Keys northward up the west coast of Florida and then inland across central/northern Florida and southeastern Georgia, following the official forecast track. A broader area of heavy rain is expected for the Florida Peninsula and eastern Panhandle, southern/eastern Georgia, South Carolina, and central/eastern North Carolina. Several inches of rain may be possible locally depending on the track of the storm, but up to an inch or more can be expected across the broader outlook area. Above normal temperatures are expected to continue for the Interior Northwest, northern Great Basin, Northern Rockies, and Northern High Plains as an upper-level ridge remains in place over the western U.S. Widespread highs in the upper 90s to low 100s are expected daily throughout the forecast period from the Northern Great Basin northward into the Interior Northwest. The daily highs at different locations may be somewhat cooler depending on the day of the week, and while the high temperatures will not be as hot as the recent historic records seen during this heatwave, the prolonged nature of above normal temperatures in general continues to remain oppressive and hazardous. Further east, high temperatures in the mid 90s to over 100 are expected for portions of eastern Montana on Wednesday, July 7th and spreading southeastward into the western Dakotas and northeastern Wyoming on Thursday, July 8th. A cold front is forecast to move southeastward across the Midwest and Northeast during the early half of the period (Monday, July 5th through Wednesday, July 7th) before becoming stationary roughly from southern New England west through the central Appalachians and back into the Midwest. Aided by northwest flow aloft, convection is expected to form along this front in the eastern Dakotas on Tuesday, July 6th, potentially organizing into a mesoscale convective system, and moving southeastward across the Mid-Missouri Valley and western portions of the Upper Mississippi Valley, bringing heavy rain. As the cold front continues eastward and stalls there may be additional chances for heavy rain, particularly in the Northeast and Mid-Atlantic as Elsa tracks northward as well. However, there is uncertainty in the position of the stationary front and the track of Elsa as well as the contribution to any shower and thunderstorm activity between the stationary front and Elsa. Therefore, no additional outlook areas were included at this time. An upper-level low as well as moist, onshore flow from the Gulf of Mexico will lead to daily showers and storms over central/southern Texas and southwestern Louisiana from Monday, July 5th through at least Thursday, July 8th. The rich Gulf moisture will lead to heavy rainfall rates and several inches of rain are possible. The heavy rain may continue on Friday, July 9th but is expected to remain more isolated to locations along the Mexican border as the upper-level low shifts to the south. For Alaska, as an initial low pressure system in the Gulf of Alaska exits to the southeast, a second low pressure system will track across the Bering Sea, the southwestern mainland, and into the Gulf of Alaska between Monday, July 5th and Thursday, July 8th. Heavy rainfall is possible across the southwest as the low approaches and begins to track across the region. Heavy rain is also possible across the Brooks Range on Tuesday, July 6th and Wednesday, July 7th as moisture increases across the area ahead of the low pressure system. Uncertainty over how significant the total amount of rainfall will be precludes an outlook area at this time. However, cooler temperatures behind the system as well as associated widespread showers will lead to below normal temperatures for the southern half of the mainland through a majority of the forecast period. Putnam