US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 346 PM EDT Fri Jun 19 2020 Valid Monday June 22 2020 - Friday June 26 2020 Hazards: - Heavy rain across portions of the Central/Southern Plains, the Middle/Lower Mississippi Valley, the Tennessee Valley, the Southeast, and the Ohio Valley, Mon-Wed, Jun 22-Jun 24. - Heavy rain across portions of the Southern Plains, Wed-Fri, Jun 24-Jun 26. - Flooding possible across portions of the Upper/Middle Mississippi Valley and the Great Lakes. - Flooding occurring or imminent across portions of the Upper/Middle Mississippi Valley, the Mid-Atlantic, the Northern Plains, and the Northern Rockies. - Flooding likely across portions of the Mid-Atlantic. - Much above normal temperatures across portions of California, the Great Basin, the Pacific Northwest, and the Southwest, Mon-Fri, Jun 22-Jun 26. - Much above normal temperatures across portions of the Great Basin and the Pacific Northwest, Tue-Wed, Jun 23-Jun 24. - Much above normal temperatures across portions of the Northeast, Mon-Wed, Jun 22-Jun 24. Detailed Summary: During the medium range period (Monday 6/22 to Friday 6/26), an upper-level low is expected to move slowly eastward across south-central and southeastern Canada. Ahead of this low, warmer than average temperatures will persist across the Northeast through the first half of next week, with temperatures nearing or exceeding 90 degrees. A cold front is forecast to push through the region around midweek, which should bring temperatures closer to normal. Moisture from the Gulf of Mexico is forecast to flow into the vicinity of a couple of fronts in south-central parts of the U.S., causing the potential for rain and thunderstorms. Heavy rain is currently expected to focus over the Middle Mississippi Valley Monday, while some modest to locally heavy rainfall totals are possible farther north into the Midwest and Ohio Valley along northern portions of the front. As the front slowly presses southeastward, so will the precipitation chances, and the Southern Plains, Lower Mississippi Valley, and parts of the Tennessee Valley could see heavy rainfall Tuesday into Wednesday. Then, the best chance of heavy rainfall totals should focus along coastal southern Texas. While there is some potential for heavy rain farther inland to the west or north, model guidance varies regarding amounts and extent. Late in the week, there is also the possibility of another rain event for the Central Plains to Midwest, but once again there is not a good model consensus, so will need to continue monitoring that potential. In the West, upper-level ridging should take hold through Wednesday, causing above normal temperatures across much of the West Coast states and into the Great Basin. By Thursday and Friday, troughing is forecast to move into the Northwest, but warmth should still continue to the south over California and western Nevada. Localized areas of excessive heat are possible, especially for the Sacramento Valley and the Mojave Desert. The Southwest can also expect very hot temperatures, but just a few degrees above normal for this time of year. Over Alaska, a wet pattern is expected for much of the state--the Panhandle should see rain for the first half of the workweek, a surface low pressure system moving across could create precipitation over the Aleutians to the Alaska Peninsula around midweek, and portions of the mainland could see scattered convection through the period. However, there is not currently any consistent model signal for widespread or heavy precipitation amounts, so no hazard area was delineated. Additionally, cooler than normal temperatures are forecast for northwestern portions of the state, but should not create hazardous conditions for this time of year. The same is true for southern portions of the mainland and Panhandle. Higher elevations of the southeastern mainland could experience low temperatures below freezing, however. Tate