Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK
0315 AM CDT Sat Aug 01 2020 Valid 041200Z - 091200Z ...DISCUSSION...
The primary severe threats in the extended range will continue to be
associated with the eastern trough and T.C. Isaias on D4/Tuesday,
and with persistent northwesterly flow across portions of the Plains
for much of the week. Predictability remains much too low to
delineate any 15% areas associated with either of these regimes. ...D4/Tuesday: Carolinas into New England...
If the track of Isaias is far enough west, then some tornado threat
may evolve on Tuesday from the Mid Atlantic coast into southern New
England, associated directly with the tropical cyclone. Otherwise,
some organized convection will be possible in advance of Isaias, as
tropical moisture streams northward into a region of moderate
low/mid-level southwesterly flow. Depending on the magnitude of
instability that can develop, locally damaging wind or a brief
tornado or two would be possible within this regime, though
uncertainty remains quite high at this time. ...Plains...
Any severe threat on D4/Tuesday in this region would probably again
be confined to the High Plains and adjacent higher terrain, though
midlevel flow will likely become more westerly (resulting in weaker
deep-layer shear) as the upper ridge moves slowly eastward. Later in
the week, the northwesterly flow regime may shift eastward into a
larger portion of the Great Plains, where low-level moisture and
instability will be gradually increasing with time, but uncertainty
regarding any specific threats remains quite high through the week.