11AM Day 2 Convective Outlook for Tuesday, February 17. NO SEVERE THUNDERSTORM AREAS FORECAST
SUMMARY
Thunderstorms are possible across Pacific coastal areas and the Central Valley of California Tuesday into Tuesday night, as well as across parts of the mid Missouri Valley into Upper Midwest Tuesday night. However, the risk for severe storms currently appears low.
California
In the wake of a mid/upper-level shortwave trough ejecting across the Great Basin/Four Corners region, another strong trough will dig southeastward along the Pacific Coast on Tuesday, as a powerful mid/upper-level jet begins to impinge upon the California coast. Ascent attendant to the trough/jet and cold temperatures aloft will support low-topped convection along much of the California coast, and also within parts of the interior valleys. The strongest low/midlevel flow will move over the central/northern CA coast and valleys during the day and evening, and over the southern CA coastal region later Tuesday night. Gusty winds and small hail will be possible with low-topped convection across these regions. At this time, it appears that convection will be quite shallow, which is expected to limit the organized severe threat. However, trends will continue to be monitored regarding potential for a low-probability wind and brief-tornado threat associated with this strong system.
Missouri Valley/Midwest
The mid/upper-level shortwave trough initially near the eastern Great Basin and Four Corners region will eject rapidly northeastward and take on a negative tilt on Tuesday, reaching the central/northern Plains by late afternoon into the evening, and the Upper Midwest/Great Lakes by early Wednesday morning. In response to this shortwave trough, a deep surface low will consolidate across the northern High Plains, and then move across the Dakotas. A trailing cold front will move across parts of the Great Plains.
Low-level moisture return along/ahead of the front is expected to remain quite limited, but strong ascent and modest moistening above the surface could support elevated convection from very late afternoon into Tuesday night across parts of the MO Valley and Upper Midwest. The signal for robust convection is currently muted, with the general thunderstorm area reflecting a broad region of low but nonzero potential. With strong low/midlevel flow and robust diurnal heating/mixing expected across the warm sector, the environment will be conditionally favorable for strong to locally severe gusts, if deep convection can be sustained.