US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
441 PM EDT Wed May 01 2019
 
Valid Saturday May 04 2019 - Wednesday May 08 2019
 
Hazards:
- Heavy precipitation across portions of the Northern Plains and the Northern Rockies, Mon-Tue, May 
6-May 7.
- Heavy rain across portions of the Central Plains, the Lower Mississippi Valley, the Great Lakes, 
the Middle Mississippi Valley, the Upper Mississippi Valley, the Southern Plains, and the Ohio 
Valley, Mon-Tue, May 6-May 7.
- Heavy rain across portions of the Central Plains, the Lower Mississippi Valley, the Tennessee 
Valley, the Central Rockies, the Middle Mississippi Valley, the Southeast, the Southern Plains, and 
the Ohio Valley, Wed, May 8.
- Heavy rain across portions of the Mid-Atlantic, the Northeast, and the Central Appalachians, 
Sat-Sun, May 4-May 5.
- Flooding possible across portions of the Central Plains, the Middle Mississippi Valley, the Great 
Lakes, the Ohio Valley, and the Upper Mississippi Valley.
- Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Northern 
Plains, the Great Lakes, the Northern Great Basin, the Middle Mississippi Valley, the Upper 
Mississippi Valley, the Southern Plains, and the Ohio Valley.
- Flooding likely across portions of the Central Plains, the Middle Mississippi Valley, the Lower 
Mississippi Valley, and the Southern Plains.
 
Detailed Summary:

The southern and central portions of the U.S. will be in an active, wet pattern. A deep layer of 
moisture from the Gulf of Mexico will interact with a slow moving frontal boundary aligned in a 
generally east to west to generate widespread convection. Rain is expected to become heavy at times 
and will generally fall over areas that have had recent excessive rainfall and/or areas that are 
experiencing ongoing river flooding. One round of organized showers and thundershowers are expected 
Friday into early Saturday as a short wave trough of Pacific origin moves across the Southern 
Plains and Lower Mississippi Valley. Eastern Texas will most likely receive the highest rainfall 
amount. Areal average amounts of 1-2 inches are forecast, however isolated higher amounts of 4 or 
more inches are possible in areas with repeat storm activity.

The front will sink southward once this shortwave passes, allowing drier air to filter in from the 
north and reduce the rain chances during Saturday through the end of the weekend. Short wave energy 
within the subtropical stream will track from northern Mexico through the Southern Plains and Lower 
Mississippi Valley; bringing another round of widespread showers and thunderstorms to the southern 
tier of the U.S. There continues to be quite a bit of uncertainty with the timing of this system, 
but it is likely to tap into some very deep Gulf of Mexico moisture as it moves into the U.S. 
Current guidance suggests that the heaviest rainfall, roughly 3 to 5 inches, will align across 
eastern Texas and the Lower/Middle Mississippi Valley Monday into Tuesday. Farther north, a surface 
low forming along a stationary front stretching across the Central Plains and Northern Rockies will 
help strengthen the southerly flow at low levels and tap into some of the aforementioned Gulf 
moisture. Increased convergence associated with this surface low along the front may support 
development of another area of organized convection across the north-central Plains late Tuesday. 
But again, confidence is low as there's a lot of uncertainty among the model solutions.

No hazards are forecast over Alaska at this point in time.

Campbell/Klein