US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
317 PM EDT Tue Apr 30 2019
 
Valid Friday May 03 2019 - Tuesday May 07 2019
 
Hazards:
- Heavy rain across portions of the Lower Mississippi Valley and the Southern Plains, Fri, May 3.
- Heavy rain across portions of the Middle Mississippi Valley, the Lower Mississippi Valley, the 
Southern Plains, and the Tennessee Valley, Mon-Tue, May 6-May 7.
- Heavy rain across portions of the Central Plains and the Middle Mississippi Valley, Tue, May 7.
- Flooding possible across portions of the Central Plains, the Lower Mississippi Valley, the 
Northern Plains, the Great Lakes, the Middle Mississippi Valley, the Upper Mississippi Valley, the 
Southern Plains, and the Ohio 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 Southern Plains and the Central Great Basin.
 
Detailed Summary:

The main concern for this forecast period will be the potential for a continuation of the wet 
pattern across the south-central U.S. A meandering frontal boundary aligned in a generally east to 
west manner will provide the focusing mechanism for deep Gulf of Mexico moisture through the 
period. 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. At this time, the best chance for heavy rainfall is expected over eastern Texas; areal 
average amounts will range from 1-2 inches, however upwards of 4+ inches are locally possible in 
areas with repeat storm activity.

With the passage of this short wave, the front will sink a little southward, allowing drier air to 
filter in from the north and reduce the rain chances during Saturday through the end of the 
weekend. However, at the beginning of next week, there are indications that a short wave embedded 
in the subtropical stream will push out of northern Mexico across the southern Plains and lower 
Mississippi Valley. There is a lot of uncertainty regarding 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. Right now, our 
thinking is that the heaviest rainfall (locally upwards of 3-5 inches) will be across eastern Texas 
and the lower-mid Mississippi Valley Monday into Tuesday, but given the currently large model 
differences, confidence in this scenario is relatively low. 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 abovementioned 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.

Klein