SPC AC 090719
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0219 AM CDT Tue Apr 09 2019
Valid 111200Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
ILLINOIS AND INDIANA...
Scattered thunderstorms capable of damaging wind gusts are possible
in Illinois/Indiana and western Kentucky Thursday afternoon.
A vigorous mid-level disturbance - initially centered over Nebraska
at the start of the period - will maintain its intensity while
lifting northward toward the western Great Lakes region Thursday.
On the southern and eastern periphery of this disturbance, a belt of
very strong (80-100 kt) mid-level flow will shift eastward,
overspreading portions of the Mississippi and Ohio River Valleys.
Meanwhile at the surface, a deeply occluded low will migrate from
eastern Nebraska into southern Minnesota. A low-level moist axis -
characterized by 50s F dewpoints - will shift eastward just ahead of
a cold front that should reach western Illinois, southeastern
Missouri, and eastern Arkansas by the early evening.
...Portions of the Midwest southward to western Kentucky...
The combination of strong forcing/ascent associated with the
mid-level disturbance and cold front will likely result in evolution
of a linear convective complex that should progress
eastward/northeastward across the Marginal and Slight Risk areas
Thursday afternoon. Surface-based instability should be marginal
owing to poor mid-level lapse rates, although very strong wind
fields aloft (exceeding 90-100 kts above 650 mb across the region)
will enhance convective downdraft potential and result in a risk of
damaging wind gusts. This threat should mainly be diurnally driven,
with weakening buoyancy limiting the severe threat with eastward
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z