US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
319 PM EDT Thu May 09 2019
 
Valid Sunday May 12 2019 - Thursday May 16 2019
 
Hazards:
- Heavy rain across portions of the Southern High Plains, Sun-Mon, May 12-May 13.
- Heavy rain across portions of the Lower Mississippi Valley and the Southern Plains, Tue-Wed, May 
14-May 15.
- Heavy rain across portions of the Southern and Central Appalachians, the Southeast, the 
Mid-Atlantic, and the Northeast, Sun, May 12.
- Flooding possible across portions the Southern Plains, the Lower Mississippi Valley, and the 
Midwest.
- Flooding occurring or imminent across portions of the Mississippi River Valley, and the Southern, 
Central, and Northern Plains.
- Flooding likely across portions of the Southern Plains, and the Mississippi and Missouri River 
Basins.
- Much above normal temperatures across portions of the interior Pacific Northwest, Sun-Mon, May 
12-May 13.
 
Detailed Summary:

The Southern U.S. will continue to be fairly active through the medium range period as an upper 
level shortwave ejecting into the Southern Plains early next week interacts with pooling moisture 
along a nearly stationary frontal boundary along/just off the Gulf Coast. Widespread, potentially 
heavy, rainfall is likely initially across parts of the Southern High Plains Sunday into Monday 
(May 12-13), and spreading into central/southeast Texas and the lower Mississippi Valley by 
Tuesday-Wednesday (May 14-15). Given heavy rainfall forecast during the short range period, and the 
already over saturated and highly susceptible soils to additional rainfall, flooding and/or flash 
flooding may be a concern. The rainfall will shift eastward later in the week with the core of the 
heaviest rainfall looking to stay offshore, but may bring a round of heavy rainfall to parts of 
southern Florida by next Thursday. Given continued model uncertainties on the intensity and impact 
of this rainfall, a heavy rain area was not included across Florida for today, but may need to be 
reconsidered in the coming days. 

To the East, the northern part of the stalled Gulf of Mexico boundary will push eastward through 
the Eastern U.S. on Sunday as a surface low along the boundary lifts through the Mid-Atlantic and 
off the Northeast coast. This will bring a period of potentially heavy rainfall along and ahead of 
the boundary from the Southeast/Southern Appalachians northward into the Mid-Atlantic and parts of 
New England on Sunday and into early Monday. 

Temperature anomalies across the majority of the country during the medium range period look to be 
below criteria and thus not expected to be a hazard. The exception to this is across parts of the 
Northwest where daytime highs could be 10 to 20 degrees above average. This would result in 
afternoon temperatures in the 80s to mid-90s, especially across parts of Washington and northern 
Oregon (east of the Cascades). For this reason, a much above normal temperatures area was added to 
the chart today for this region spanning Sunday, May 12 - Monday, May 13. Temperatures should 
moderate and shift eastward through the rest of the week and should be below hazards criteria.

Santorelli