US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 339 PM EDT Fri Mar 29 2019 Valid Monday April 01 2019 - Friday April 05 2019 Hazards: - Heavy precipitation across portions of the Pacific Northwest, Mon-Tue, Apr 1-Apr 2. - Heavy rain across portions of the Southeast, the Mid-Atlantic, the Pacific Northwest, northern California, and the northern Great Basin, Mon-Tue, Apr 1-Apr 2. - Heavy rain across portions of northern California, southwestern Oregon, and the Olympic Mountains, Fri, Apr 5. - Heavy snow across portions of the Central Rockies, the central Great Basin, the northern Rockies, the northern Great Basin, and the northern Plains, Tue-Wed, Apr 2-Apr 3. - Heavy snow across portions of the northern Rockies and the northern Great Basin, Tue, Apr 2. - Flooding possible across portions of the upper Mississippi Valley, the middle Mississippi Valley, the northern Plains, and the northern Great Basin. - Flooding occurring or imminent across portions of the central Plains, the lower Mississippi Valley, the northern Plains, the Tennessee Valley, the middle Mississippi Valley, the upper Mississippi Valley, the Great Lakes, and the Ohio Valley. - Flooding likely across portions of the middle Mississippi Valley. - High winds across portions of the Northeast, Wed, Apr 3. - High winds across portions of the Mid-Atlantic, Tue-Wed, Apr 2-Apr 3. Detailed Summary: Model guidance continues to signal the likelihood of a coastal storm forming along a stationary front over northern Florida later on Monday, which could then intensify rapidly and impact the Southeast U.S. and the Mid-Atlantic coast Tuesday into early on Wednesday. There had been a notable model trend earlier today toward a stronger and more progressive storm passing closer to the North Carolina coast by late on Tuesday. The latest 12Z model runs (both the GFS and ECMWF) have taken the storm faster and further out to sea. With the model solutions continue to show considerable fluctuations, uncertainty remains high regarding the exact track and intensity of this storm. Nevertheless, based on a consensus of the morning model guidance, a heavy rain area is indicated from the Florida panhandle to the Southeast and further into the Mid-Atlantic coast from Monday (Apr 1) to Tuesday (Apr 2), along with the possibility of high winds near the North Carolina coast, and could brush southeastern New England on Wednesday (Apr 3). There is even a possibility of wintry precipitation spreading from south to northern along the Appalachians into New England during this period but the confidence and the accumulation amounts are not high enough to warrant a heavy precipitation hazard area at this time. Farther west, moisture associated with the next Pacific cyclone should reach the Oregon coast on Monday. The bulk of the moisture should penetrate further into Oregon Monday night, and then into Idaho on Tuesday. It appears that western Oregon southward into northern California will have the best chance of seeing heavy rain Monday night into Tuesday (Apr 2) while the higher elevations of the Oregon Cascades may see wet snow mixing in. A better chance of seeing heavy wet snow will be across the Bitter Roots of Idaho on Tuesday, followed by the higher elevations of northwestern Wyoming Tuesday into early Wednesday. As we head toward the end of next week, models show good agreement that heavy rain associated with large Pacific cyclone will reach northern California, southwestern Oregon, and the Olympic Mountains later on Friday, where heavy rain hazard areas are indicated. Moderate to major flooding across the Mississippi and Missouri River Basins is expected to continue through the forecast period. The aforementioned trough which is forecast to impact the western states early next week is expected to move out into the Plains during the middle of next week. Precipitation over the Plains and Mississippi Valleys will break out as this trough lifts northward and interacts with increasing moisture from the Gulf of Mexico. However, it appears the rain will not be heavy and widespread enough to warrant a heavy rain hazard area at this time. Alaska will again remain fairly quiet during the medium range period as upper ridging continues to dominate. The pressure gradient between high pressure over the state and Gulf of Alaska together with a series of cyclones tracking south of the Aleutians may bring moderate winds and waves to parts of the Aleutian chain during the early-mid part of next week. At this time, neither appear strong enough to support hazard areas. Kong